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chromium / v8 / v8 / 386675c40e28dcfaacaeef342d3ac3bd9ce4129f / . / src / flags / flag-definitions.h
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// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This file defines all of the flags. It is separated into different section,
// for Debug, Release, Logging and Profiling, etc. To add a new flag, find the
// correct section, and use one of the DEFINE_ macros, without a trailing ';'.
//
// This include does not have a guard, because it is a template-style include,
// which can be included multiple times in different modes. It expects to have
// a mode defined before it's included. The modes are FLAG_MODE_... below:
//
// PRESUBMIT_INTENTIONALLY_MISSING_INCLUDE_GUARD
#define DEFINE_IMPLICATION(whenflag, thenflag) \
DEFINE_VALUE_IMPLICATION(whenflag, thenflag, true)
// A weak implication will be overwritten by a normal implication or by an
// explicit flag.
#define DEFINE_WEAK_IMPLICATION(whenflag, thenflag) \
DEFINE_WEAK_VALUE_IMPLICATION(whenflag, thenflag, true)
#define DEFINE_WEAK_NEG_IMPLICATION(whenflag, thenflag) \
DEFINE_WEAK_VALUE_IMPLICATION(whenflag, thenflag, false)
#define DEFINE_NEG_IMPLICATION(whenflag, thenflag) \
DEFINE_VALUE_IMPLICATION(whenflag, thenflag, false)
#define DEFINE_NEG_NEG_IMPLICATION(whenflag, thenflag) \
DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, false)
// With FLAG_MODE_DECLARE we declare the fields in the {FlagValues} struct.
// Read-only flags are static constants instead of fields.
#if defined(FLAG_MODE_DECLARE)
#define FLAG_FULL(ftype, ctype, nam, def, cmt) FlagValue<ctype> nam{def};
#define FLAG_READONLY(ftype, ctype, nam, def, cmt) \
static constexpr FlagValue<ctype> nam{def};
// We need to define all of our default values so that the Flag structure can
// access them by pointer. These are just used internally inside of one .cc,
// for MODE_META, so there is no impact on the flags interface.
#elif defined(FLAG_MODE_DEFINE_DEFAULTS)
#define FLAG_FULL(ftype, ctype, nam, def, cmt) \
static constexpr ctype FLAGDEFAULT_##nam{def};
#define FLAG_READONLY(ftype, ctype, nam, def, cmt) \
static constexpr ctype FLAGDEFAULT_##nam{def};
// We want to write entries into our meta data table, for internal parsing and
// printing / etc in the flag parser code.
#elif defined(FLAG_MODE_META)
#define FLAG_FULL(ftype, ctype, nam, def, cmt) \
{Flag::TYPE_##ftype, #nam, &v8_flags.nam, &FLAGDEFAULT_##nam, cmt, false},
// Readonly flags don't pass the value pointer since the struct expects a
// mutable value. That's okay since the value always equals the default.
#define FLAG_READONLY(ftype, ctype, nam, def, cmt) \
{Flag::TYPE_##ftype, #nam, nullptr, &FLAGDEFAULT_##nam, cmt, false},
#define FLAG_ALIAS(ftype, ctype, alias, nam) \
{Flag::TYPE_##ftype, #alias, &v8_flags.nam, &FLAGDEFAULT_##nam, \
"alias for --" #nam, false}, // NOLINT(whitespace/indent)
// We produce the code to set flags when it is implied by another flag.
#elif defined(FLAG_MODE_DEFINE_IMPLICATIONS)
#define DEFINE_VALUE_IMPLICATION(whenflag, thenflag, value) \
changed |= TriggerImplication(v8_flags.whenflag, #whenflag, \
&v8_flags.thenflag, #thenflag, value, false);
// A weak implication will be overwritten by a normal implication or by an
// explicit flag.
#define DEFINE_WEAK_VALUE_IMPLICATION(whenflag, thenflag, value) \
changed |= TriggerImplication(v8_flags.whenflag, #whenflag, \
&v8_flags.thenflag, #thenflag, value, true);
#define DEFINE_GENERIC_IMPLICATION(whenflag, statement) \
if (v8_flags.whenflag) statement;
#define DEFINE_REQUIREMENT(statement) CHECK(statement);
#define DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, value) \
changed |= TriggerImplication(!v8_flags.whenflag, "!" #whenflag, \
&v8_flags.thenflag, #thenflag, value, false);
#define DEFINE_NEG_VALUE_VALUE_IMPLICATION(whenflag, whenvalue, thenflag, \
thenvalue) \
changed |= \
TriggerImplication(v8_flags.whenflag != whenvalue, #whenflag, \
&v8_flags.thenflag, #thenflag, thenvalue, false);
#define DEFINE_MIN_VALUE_IMPLICATION(flag, min_value) \
changed |= TriggerImplication(v8_flags.flag < min_value, #flag, \
&v8_flags.flag, #flag, min_value, false);
#define DEFINE_DISABLE_FLAG_IMPLICATION(whenflag, thenflag) \
if (v8_flags.whenflag && v8_flags.thenflag) { \
PrintF(stderr, "Warning: disabling flag --" #thenflag \
" due to conflicting flags\n"); \
} \
DEFINE_VALUE_IMPLICATION(whenflag, thenflag, false)
// We apply a generic macro to the flags.
#elif defined(FLAG_MODE_APPLY)
#define FLAG_FULL FLAG_MODE_APPLY
#else
#error No mode supplied when including flags.defs
#endif
// Dummy defines for modes where it is not relevant.
#ifndef FLAG_FULL
#define FLAG_FULL(ftype, ctype, nam, def, cmt)
#endif
#ifndef FLAG_READONLY
#define FLAG_READONLY(ftype, ctype, nam, def, cmt)
#endif
#ifndef FLAG_ALIAS
#define FLAG_ALIAS(ftype, ctype, alias, nam)
#endif
#ifndef DEFINE_VALUE_IMPLICATION
#define DEFINE_VALUE_IMPLICATION(whenflag, thenflag, value)
#endif
#ifndef DEFINE_WEAK_VALUE_IMPLICATION
#define DEFINE_WEAK_VALUE_IMPLICATION(whenflag, thenflag, value)
#endif
#ifndef DEFINE_GENERIC_IMPLICATION
#define DEFINE_GENERIC_IMPLICATION(whenflag, statement)
#endif
#ifndef DEFINE_NEG_VALUE_IMPLICATION
#define DEFINE_NEG_VALUE_IMPLICATION(whenflag, thenflag, value)
#endif
#ifndef DEFINE_NEG_VALUE_VALUE_IMPLICATION
#define DEFINE_NEG_VALUE_VALUE_IMPLICATION(whenflag, whenvalue, thenflag, \
thenvalue)
#endif
#ifndef DEFINE_MIN_VALUE_IMPLICATION
#define DEFINE_MIN_VALUE_IMPLICATION(flag, min_value)
#endif
#ifndef DEFINE_DISABLE_FLAG_IMPLICATION
#define DEFINE_DISABLE_FLAG_IMPLICATION(whenflag, thenflag)
#endif
#ifndef DEFINE_REQUIREMENT
#define DEFINE_REQUIREMENT(statement)
#endif
#ifndef DEBUG_BOOL
#error DEBUG_BOOL must be defined at this point.
#endif // DEBUG_BOOL
#if V8_ENABLE_SPARKPLUG
#define ENABLE_SPARKPLUG_BY_DEFAULT true
#else
#define ENABLE_SPARKPLUG_BY_DEFAULT false
#endif
// Supported ARM configurations are:
// "armv6": ARMv6 + VFPv2
// "armv7": ARMv7 + VFPv3-D32 + NEON
// "armv7+sudiv": ARMv7 + VFPv4-D32 + NEON + SUDIV
// "armv8": ARMv8 (including all of the above)
#if !defined(ARM_TEST_NO_FEATURE_PROBE) || \
(defined(CAN_USE_ARMV8_INSTRUCTIONS) && \
defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_SUDIV) && \
defined(CAN_USE_NEON) && defined(CAN_USE_VFP3_INSTRUCTIONS))
#define ARM_ARCH_DEFAULT "armv8"
#elif defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_SUDIV) && \
defined(CAN_USE_NEON) && defined(CAN_USE_VFP3_INSTRUCTIONS)
#define ARM_ARCH_DEFAULT "armv7+sudiv"
#elif defined(CAN_USE_ARMV7_INSTRUCTIONS) && defined(CAN_USE_NEON) && \
defined(CAN_USE_VFP3_INSTRUCTIONS)
#define ARM_ARCH_DEFAULT "armv7"
#else
#define ARM_ARCH_DEFAULT "armv6"
#endif
#ifdef V8_OS_WIN
#define ENABLE_LOG_COLOUR false
#else
#define ENABLE_LOG_COLOUR true
#endif
#define DEFINE_BOOL(nam, def, cmt) FLAG(BOOL, bool, nam, def, cmt)
#define DEFINE_BOOL_READONLY(nam, def, cmt) \
FLAG_READONLY(BOOL, bool, nam, def, cmt)
#define DEFINE_MAYBE_BOOL(nam, cmt) \
FLAG(MAYBE_BOOL, std::optional<bool>, nam, std::nullopt, cmt)
#define DEFINE_INT(nam, def, cmt) FLAG(INT, int, nam, def, cmt)
#define DEFINE_UINT(nam, def, cmt) FLAG(UINT, unsigned int, nam, def, cmt)
#define DEFINE_UINT_READONLY(nam, def, cmt) \
FLAG_READONLY(UINT, unsigned int, nam, def, cmt)
#define DEFINE_UINT64(nam, def, cmt) FLAG(UINT64, uint64_t, nam, def, cmt)
#define DEFINE_FLOAT(nam, def, cmt) FLAG(FLOAT, double, nam, def, cmt)
#define DEFINE_SIZE_T(nam, def, cmt) FLAG(SIZE_T, size_t, nam, def, cmt)
#define DEFINE_STRING(nam, def, cmt) FLAG(STRING, const char*, nam, def, cmt)
#define DEFINE_ALIAS_BOOL(alias, nam) FLAG_ALIAS(BOOL, bool, alias, nam)
#define DEFINE_ALIAS_INT(alias, nam) FLAG_ALIAS(INT, int, alias, nam)
#define DEFINE_ALIAS_FLOAT(alias, nam) FLAG_ALIAS(FLOAT, double, alias, nam)
#define DEFINE_ALIAS_SIZE_T(alias, nam) FLAG_ALIAS(SIZE_T, size_t, alias, nam)
#define DEFINE_ALIAS_STRING(alias, nam) \
FLAG_ALIAS(STRING, const char*, alias, nam)
#ifdef DEBUG
#define DEFINE_DEBUG_BOOL DEFINE_BOOL
#else
#define DEFINE_DEBUG_BOOL DEFINE_BOOL_READONLY
#endif
//
// Flags in all modes.
//
#define FLAG FLAG_FULL
// Experimental features.
// Features that are still considered experimental and which are not ready for
// fuzz testing should be defined using this macro. The feature will then imply
// --experimental, which will indicate to the user that they are running an
// experimental configuration of V8. Experimental features are always disabled
// by default. When these features mature, the flag should first turn into a
// regular feature flag (still disabled by default) and then ideally be staged
// behind (for example) --future before being enabled by default.
DEFINE_BOOL(experimental, false,
"Indicates that V8 is running with experimental features enabled. "
"This flag is typically not set explicitly but instead enabled as "
"an implication of other flags which enable experimental features.")
#define DEFINE_EXPERIMENTAL_FEATURE(nam, cmt) \
FLAG(BOOL, bool, nam, false, cmt " (experimental)") \
DEFINE_IMPLICATION(nam, experimental)
// ATTENTION: This is set to true by default in d8. But for API compatibility,
// it generally defaults to false.
DEFINE_BOOL(abort_on_contradictory_flags, false,
"Disallow flags or implications overriding each other.")
// This implication is also hard-coded into the flags processing to make sure it
// becomes active before we even process subsequent flags.
DEFINE_NEG_IMPLICATION(fuzzing, abort_on_contradictory_flags)
// As abort_on_contradictory_flags, but it will simply exit with return code 0.
DEFINE_BOOL(exit_on_contradictory_flags, false,
"Exit with return code 0 on contradictory flags.")
// We rely on abort_on_contradictory_flags to turn on the analysis.
DEFINE_WEAK_IMPLICATION(exit_on_contradictory_flags,
abort_on_contradictory_flags)
// This is not really a flag, it affects the interpretation of the next flag but
// doesn't become permanently true when specified. This only works for flags
// defined in this file, but not for d8 flags defined in src/d8/d8.cc.
DEFINE_BOOL(allow_overwriting_for_next_flag, false,
"temporary disable flag contradiction to allow overwriting just "
"the next flag")
// Flags for language modes and experimental language features.
DEFINE_BOOL(use_strict, false, "enforce strict mode")
DEFINE_BOOL(trace_temporal, false, "trace temporal code")
DEFINE_BOOL(harmony, false, "enable all completed harmony features")
DEFINE_BOOL(harmony_shipping, true, "enable all shipped harmony features")
DEFINE_BOOL(js_staging, false, "enable all completed JavaScript features")
DEFINE_BOOL(js_shipping, true, "enable all shipped JavaScript features")
// Update bootstrapper.cc whenever adding a new feature flag.
// Features that are still work in progress (behind individual flags).
//
// The "harmony" naming is now outdated and will no longer be used for new JS
// features. Use the JAVASCRIPT macros instead.
//
// TODO(v8:14214): Remove --harmony flags once transition is complete.
#define HARMONY_INPROGRESS_BASE(V) \
V(harmony_temporal, "Temporal") \
V(harmony_shadow_realm, "harmony ShadowRealm") \
V(harmony_struct, "harmony structs, shared structs, and shared arrays")
#define JAVASCRIPT_INPROGRESS_FEATURES_BASE(V) \
V(js_decorators, "decorators") \
V(js_source_phase_imports, "source phase imports")
#ifdef V8_INTL_SUPPORT
#define HARMONY_INPROGRESS(V) \
HARMONY_INPROGRESS_BASE(V) \
V(harmony_intl_best_fit_matcher, "Intl BestFitMatcher")
#define JAVASCRIPT_INPROGRESS_FEATURES(V) JAVASCRIPT_INPROGRESS_FEATURES_BASE(V)
#else
#define HARMONY_INPROGRESS(V) HARMONY_INPROGRESS_BASE(V)
#define JAVASCRIPT_INPROGRESS_FEATURES(V) JAVASCRIPT_INPROGRESS_FEATURES_BASE(V)
#endif
// Features that are complete (but still behind the --harmony flag).
#define HARMONY_STAGED_BASE(V)
#define JAVASCRIPT_STAGED_FEATURES_BASE(V) \
V(js_explicit_resource_management, "explicit resource management") \
V(js_float16array, \
"Float16Array, Math.f16round, DataView.getFloat16, DataView.setFloat16")
#ifdef V8_INTL_SUPPORT
#define HARMONY_STAGED(V) \
HARMONY_STAGED_BASE(V) \
V(harmony_remove_intl_locale_info_getters, \
"Remove Obsoleted Intl Locale Info getters")
#define JAVASCRIPT_STAGED_FEATURES(V) JAVASCRIPT_STAGED_FEATURES_BASE(V)
#else
#define HARMONY_STAGED(V) HARMONY_STAGED_BASE(V)
#define JAVASCRIPT_STAGED_FEATURES(V) JAVASCRIPT_STAGED_FEATURES_BASE(V)
#endif
// Features that are shipping (turned on by default, but internal flag remains).
#define HARMONY_SHIPPING_BASE(V) \
V(harmony_iterator_helpers, "JavaScript iterator helpers") \
V(harmony_set_methods, "harmony Set Methods") \
V(harmony_import_attributes, "harmony import attributes")
#define JAVASCRIPT_SHIPPING_FEATURES_BASE(V) \
V(js_regexp_duplicate_named_groups, "RegExp duplicate named groups") \
V(js_regexp_modifiers, "RegExp modifiers") \
V(js_promise_try, "Promise.try") \
V(js_atomics_pause, "Atomics.pause") \
V(js_error_iserror, "Error.isError")
#ifdef V8_INTL_SUPPORT
#define HARMONY_SHIPPING(V) HARMONY_SHIPPING_BASE(V)
#define JAVASCRIPT_SHIPPING_FEATURES(V) JAVASCRIPT_SHIPPING_FEATURES_BASE(V)
#else
#define HARMONY_SHIPPING(V) HARMONY_SHIPPING_BASE(V)
#define JAVASCRIPT_SHIPPING_FEATURES(V) JAVASCRIPT_SHIPPING_FEATURES_BASE(V)
#endif
// Once a shipping feature has proved stable in the wild, it will be dropped
// from HARMONY_SHIPPING, all occurrences of the FLAG_ variable are removed,
// and associated tests are moved from the harmony directory to the appropriate
// esN directory.
//
// In-progress features are not code complete and are considered experimental,
// i.e. not ready for fuzz testing.
#define FLAG_INPROGRESS_FEATURES(id, description) \
DEFINE_BOOL(id, false, \
"enable " #description " (in progress / experimental)") \
DEFINE_IMPLICATION(id, experimental)
HARMONY_INPROGRESS(FLAG_INPROGRESS_FEATURES)
JAVASCRIPT_INPROGRESS_FEATURES(FLAG_INPROGRESS_FEATURES)
#undef FLAG_INPROGRESS_FEATURES
#define FLAG_STAGED_FEATURES(id, description) \
DEFINE_BOOL(id, false, "enable " #description) \
DEFINE_IMPLICATION(harmony, id) \
DEFINE_IMPLICATION(js_staging, id)
HARMONY_STAGED(FLAG_STAGED_FEATURES)
JAVASCRIPT_STAGED_FEATURES(FLAG_STAGED_FEATURES)
DEFINE_IMPLICATION(harmony, js_staging)
#undef FLAG_STAGED_FEATURES
#define FLAG_SHIPPING_FEATURES(id, description) \
DEFINE_BOOL(id, true, "enable " #description) \
DEFINE_NEG_NEG_IMPLICATION(harmony_shipping, id) \
DEFINE_NEG_NEG_IMPLICATION(js_shipping, id)
HARMONY_SHIPPING(FLAG_SHIPPING_FEATURES)
JAVASCRIPT_SHIPPING_FEATURES(FLAG_SHIPPING_FEATURES)
DEFINE_NEG_NEG_IMPLICATION(harmony_shipping, js_shipping)
#undef FLAG_SHIPPING_FEATURES
DEFINE_BOOL(builtin_subclassing, true,
"subclassing support in built-in methods")
// If the following flag is set to `true`, the SharedArrayBuffer constructor is
// enabled per context depending on the callback set via
// `SetSharedArrayBufferConstructorEnabledCallback`. If no callback is set, the
// SharedArrayBuffer constructor is disabled.
DEFINE_BOOL(enable_sharedarraybuffer_per_context, false,
"enable the SharedArrayBuffer constructor per context")
#ifdef V8_INTL_SUPPORT
DEFINE_BOOL(icu_timezone_data, true, "get information about timezones from ICU")
#endif
#ifdef V8_ENABLE_DOUBLE_CONST_STORE_CHECK
#define V8_ENABLE_DOUBLE_CONST_STORE_CHECK_BOOL true
#else
#define V8_ENABLE_DOUBLE_CONST_STORE_CHECK_BOOL false
#endif
#ifdef V8_ENABLE_LAZY_SOURCE_POSITIONS
#define V8_LAZY_SOURCE_POSITIONS_BOOL true
#else
#define V8_LAZY_SOURCE_POSITIONS_BOOL false
#endif
DEFINE_BOOL(stress_snapshot, false,
"disables sharing of the read-only heap for testing")
// Incremental marking is incompatible with the stress_snapshot mode;
// specifically, serialization may clear bytecode arrays from shared function
// infos which the MarkCompactCollector (running concurrently) may still need.
// See also https://crbug.com/v8/10882.
//
// Note: This is not an issue in production because we don't clear SFI's
// there (that only happens in mksnapshot and in --stress-snapshot mode).
DEFINE_NEG_IMPLICATION(stress_snapshot, incremental_marking)
#ifdef V8_LITE_MODE
#define V8_LITE_MODE_BOOL true
#else
#define V8_LITE_MODE_BOOL false
#endif
DEFINE_BOOL(lite_mode, V8_LITE_MODE_BOOL,
"enables trade-off of performance for memory savings")
// Lite mode implies other flags to trade-off performance for memory.
DEFINE_IMPLICATION(lite_mode, jitless)
DEFINE_IMPLICATION(lite_mode, optimize_for_size)
#ifdef V8_ALLOCATION_FOLDING
#define V8_ALLOCATION_FOLDING_BOOL true
#else
#define V8_ALLOCATION_FOLDING_BOOL false
#endif
DEFINE_BOOL_READONLY(enable_allocation_folding, V8_ALLOCATION_FOLDING_BOOL,
"Use allocation folding globally")
DEFINE_NEG_NEG_IMPLICATION(enable_allocation_folding, turbo_allocation_folding)
#ifdef V8_DISABLE_WRITE_BARRIERS
#define V8_DISABLE_WRITE_BARRIERS_BOOL true
#else
#define V8_DISABLE_WRITE_BARRIERS_BOOL false
#endif
DEFINE_BOOL_READONLY(disable_write_barriers, V8_DISABLE_WRITE_BARRIERS_BOOL,
"disable write barriers when GC is non-incremental "
"and heap contains single generation.")
// Disable incremental marking barriers
DEFINE_NEG_IMPLICATION(disable_write_barriers, incremental_marking)
DEFINE_NEG_IMPLICATION(disable_write_barriers, concurrent_marking)
DEFINE_NEG_IMPLICATION(disable_write_barriers, cppheap_incremental_marking)
DEFINE_NEG_IMPLICATION(disable_write_barriers, cppheap_concurrent_marking)
#ifdef V8_ENABLE_UNCONDITIONAL_WRITE_BARRIERS
#define V8_ENABLE_UNCONDITIONAL_WRITE_BARRIERS_BOOL true
#else
#define V8_ENABLE_UNCONDITIONAL_WRITE_BARRIERS_BOOL false
#endif
DEFINE_BOOL_READONLY(enable_unconditional_write_barriers,
V8_ENABLE_UNCONDITIONAL_WRITE_BARRIERS_BOOL,
"always use full write barriers")
#ifdef V8_ENABLE_SINGLE_GENERATION
#define V8_SINGLE_GENERATION_BOOL true
#else
#define V8_SINGLE_GENERATION_BOOL false
#endif
DEFINE_BOOL_READONLY(
single_generation, V8_SINGLE_GENERATION_BOOL,
"allocate all objects from young generation to old generation")
#ifdef V8_ENABLE_CONSERVATIVE_STACK_SCANNING
#define V8_ENABLE_CONSERVATIVE_STACK_SCANNING_BOOL true
#else
#define V8_ENABLE_CONSERVATIVE_STACK_SCANNING_BOOL false
#endif
DEFINE_BOOL_READONLY(conservative_stack_scanning,
V8_ENABLE_CONSERVATIVE_STACK_SCANNING_BOOL,
"use conservative stack scanning")
DEFINE_IMPLICATION(conservative_stack_scanning, minor_ms)
DEFINE_NEG_IMPLICATION(conservative_stack_scanning, compact_with_stack)
#ifdef V8_ENABLE_DIRECT_HANDLE
#define V8_ENABLE_DIRECT_HANDLE_BOOL true
#else
#define V8_ENABLE_DIRECT_HANDLE_BOOL false
#endif
DEFINE_BOOL_READONLY(direct_handle, V8_ENABLE_DIRECT_HANDLE_BOOL,
"use direct handles with conservative stack scanning")
// Do not use direct handles without conservative stack scanning, as this would
// break the correctness of the GC.
DEFINE_NEG_NEG_IMPLICATION(conservative_stack_scanning, direct_handle)
DEFINE_EXPERIMENTAL_FEATURE(scavenger_pinning_objects,
"Objects reachable from the native stack during "
"scavenge will be pinned and "
"won't move.")
DEFINE_IMPLICATION(scavenger_pinning_objects, separate_gc_phases)
DEFINE_BOOL(stress_scavenger_pinning_objects, false,
"Treat some precise refernces as conservative references to stress "
"test object pinning in Scavenger")
DEFINE_IMPLICATION(stress_scavenger_pinning_objects, scavenger_pinning_objects)
DEFINE_BOOL(stress_scavenger_pinning_objects_random, false,
"Enables random stressing of object pinning in Scavenger, such "
"that each GC would randomly pick a subset of the precise "
"references to treat conservatively")
DEFINE_IMPLICATION(stress_scavenger_pinning_objects_random,
stress_scavenger_pinning_objects)
#ifdef V8_ENABLE_LOCAL_OFF_STACK_CHECK
#define V8_ENABLE_LOCAL_OFF_STACK_CHECK_BOOL true
#else
#define V8_ENABLE_LOCAL_OFF_STACK_CHECK_BOOL false
#endif
DEFINE_BOOL_READONLY(local_off_stack_check,
V8_ENABLE_LOCAL_OFF_STACK_CHECK_BOOL,
"check for off-stack allocation of v8::Local")
#ifdef V8_ENABLE_FUTURE
#define FUTURE_BOOL true
#else
#define FUTURE_BOOL false
#endif
DEFINE_BOOL(future, FUTURE_BOOL,
"Implies all staged features that we want to ship in the "
"not-too-far future")
DEFINE_BOOL(force_emit_interrupt_budget_checks, false,
"force emit tier-up logic from all non-turbofan code, even if it "
"is the top enabled tier")
#ifdef V8_ENABLE_MAGLEV
DEFINE_BOOL(maglev, true, "enable the maglev optimizing compiler")
#if !ENABLE_MAGLEV
// Enable Maglev on Future for platforms in which it's not enabled by default
// (eg, Android).
DEFINE_WEAK_IMPLICATION(future, maglev)
#endif
DEFINE_EXPERIMENTAL_FEATURE(
maglev_future,
"enable maglev features that we want to ship in the not-too-far future")
DEFINE_IMPLICATION(maglev_future, maglev)
DEFINE_BOOL(
optimize_on_next_call_optimizes_to_maglev, false,
"make OptimizeFunctionOnNextCall optimize to maglev instead of turbofan")
// We stress maglev by setting a very low interrupt budget for maglev. This
// way, we still gather *some* feedback before compiling optimized code.
DEFINE_BOOL(stress_maglev, false, "trigger maglev compilation earlier")
DEFINE_IMPLICATION(stress_maglev, maglev)
DEFINE_WEAK_VALUE_IMPLICATION(stress_maglev, invocation_count_for_maglev, 4)
#else
DEFINE_BOOL_READONLY(maglev, false, "enable the maglev optimizing compiler")
DEFINE_BOOL_READONLY(
maglev_future, false,
"enable maglev features that we want to ship in the not-too-far future")
DEFINE_BOOL_READONLY(stress_maglev, false, "trigger maglev compilation earlier")
DEFINE_BOOL_READONLY(
optimize_on_next_call_optimizes_to_maglev, false,
"make OptimizeFunctionOnNextCall optimize to maglev instead of turbofan")
#endif // V8_ENABLE_MAGLEV
DEFINE_BOOL(maglev_inlining, true,
"enable inlining in the maglev optimizing compiler")
DEFINE_BOOL(maglev_loop_peeling, true,
"enable loop peeling in the maglev optimizing compiler")
DEFINE_BOOL(maglev_optimistic_peeled_loops, true,
"enable aggressive optimizations for loops (loop SPeeling) in the "
"maglev optimizing compiler")
DEFINE_INT(maglev_loop_peeling_max_size, 400,
"max loop size for loop peeling in the maglev optimizing compiler")
DEFINE_INT(
maglev_loop_peeling_max_size_cumulative, 900,
"max cumulative size for loop peeling in the maglev optimizing compiler")
DEFINE_BOOL(maglev_deopt_data_on_background, true,
"Generate deopt data on background thread")
DEFINE_BOOL(maglev_build_code_on_background, true,
"Generate code on background thread")
DEFINE_WEAK_IMPLICATION(maglev_build_code_on_background,
maglev_deopt_data_on_background)
DEFINE_BOOL(maglev_destroy_on_background, true,
"Destroy compilation jobs on background thread")
DEFINE_BOOL(maglev_inline_api_calls, false,
"Inline CallApiCallback builtin into generated code")
DEFINE_EXPERIMENTAL_FEATURE(maglev_licm, "loop invariant code motion")
DEFINE_WEAK_IMPLICATION(maglev_future, maglev_speculative_hoist_phi_untagging)
DEFINE_WEAK_IMPLICATION(maglev_future, maglev_inline_api_calls)
DEFINE_WEAK_IMPLICATION(maglev_future, maglev_escape_analysis)
DEFINE_WEAK_IMPLICATION(maglev_future, maglev_licm)
// This might be too big of a hammer but we must prohibit moving the C++
// trampolines while we are executing a C++ code.
DEFINE_NEG_IMPLICATION(maglev_inline_api_calls, compact_code_space_with_stack)
DEFINE_UINT(
concurrent_maglev_max_threads, 2,
"max number of threads that concurrent Maglev can use (0 for unbounded)")
DEFINE_BOOL(concurrent_maglev_high_priority_threads, false,
"use high priority compiler threads for concurrent Maglev")
DEFINE_INT(
max_maglev_inline_depth, 1,
"max depth of functions that Maglev will inline excl. small functions")
DEFINE_INT(
max_maglev_hard_inline_depth, 10,
"max depth of functions that Maglev will inline incl. small functions")
DEFINE_INT(max_maglev_inlined_bytecode_size, 460,
"maximum size of bytecode for a single inlining")
DEFINE_INT(max_maglev_inlined_bytecode_size_cumulative, 920,
"maximum cumulative size of bytecode considered for inlining excl. "
"small functions")
DEFINE_INT(max_maglev_inlined_bytecode_size_small, 27,
"maximum size of bytecode considered for small function inlining")
DEFINE_FLOAT(min_maglev_inlining_frequency, 0.10,
"minimum frequency for inlining")
DEFINE_WEAK_VALUE_IMPLICATION(turbofan, max_maglev_inline_depth, 1)
DEFINE_WEAK_VALUE_IMPLICATION(turbofan, max_maglev_inlined_bytecode_size, 100)
DEFINE_WEAK_VALUE_IMPLICATION(turbofan,
max_maglev_inlined_bytecode_size_cumulative, 920)
DEFINE_WEAK_VALUE_IMPLICATION(turbofan, min_maglev_inlining_frequency, 0.95)
DEFINE_BOOL(maglev_reuse_stack_slots, true,
"reuse stack slots in the maglev optimizing compiler")
DEFINE_BOOL(maglev_untagged_phis, true,
"enable phi untagging in the maglev optimizing compiler")
DEFINE_BOOL(maglev_hoist_osr_value_phi_untagging, true,
"enable phi untagging to hoist untagging of osr values")
DEFINE_EXPERIMENTAL_FEATURE(
maglev_speculative_hoist_phi_untagging,
"enable phi untagging to hoist untagging of loop phi inputs (could "
"still cause deopt loops)")
DEFINE_BOOL(maglev_cse, true, "common subexpression elimination")
DEFINE_STRING(maglev_filter, "*", "optimization filter for the maglev compiler")
DEFINE_STRING(maglev_print_filter, "*",
"filter for maglev's tracing/printing options")
DEFINE_BOOL(maglev_assert, false, "insert extra assertion in maglev code")
DEFINE_DEBUG_BOOL(maglev_assert_stack_size, true,
"insert stack size checks before every IR node")
DEFINE_BOOL(maglev_break_on_entry, false, "insert an int3 on maglev entries")
DEFINE_BOOL(maglev_print_feedback, true,
"print feedback vector for maglev compiled code")
DEFINE_BOOL(maglev_print_inlined, true,
"print bytecode / feedback vectors also for inlined code")
DEFINE_BOOL(print_maglev_code, false, "print maglev code")
DEFINE_BOOL(trace_maglev_graph_building, false, "trace maglev graph building")
DEFINE_BOOL(trace_maglev_loop_speeling, false, "trace maglev loop SPeeling")
DEFINE_WEAK_IMPLICATION(trace_maglev_graph_building, trace_maglev_loop_speeling)
DEFINE_BOOL(trace_maglev_inlining, false, "trace maglev inlining")
DEFINE_BOOL(trace_maglev_inlining_verbose, false,
"trace maglev inlining (verbose)")
DEFINE_IMPLICATION(trace_maglev_inlining_verbose, trace_maglev_inlining)
#ifdef V8_ENABLE_MAGLEV_GRAPH_PRINTER
DEFINE_BOOL(print_maglev_deopt_verbose, false, "print verbose deopt info")
DEFINE_WEAK_IMPLICATION(trace_deopt_verbose, print_maglev_deopt_verbose)
DEFINE_BOOL(print_maglev_graph, false, "print the final maglev graph")
DEFINE_BOOL(print_maglev_graphs, false, "print maglev graph across all phases")
DEFINE_BOOL(trace_maglev_phi_untagging, false, "trace maglev phi untagging")
DEFINE_BOOL(trace_maglev_regalloc, false, "trace maglev register allocation")
#else
DEFINE_BOOL_READONLY(print_maglev_deopt_verbose, false,
"print verbose deopt info")
DEFINE_BOOL_READONLY(print_maglev_graph, false, "print the final maglev graph")
DEFINE_BOOL_READONLY(print_maglev_graphs, false,
"print maglev graph across all phases")
DEFINE_BOOL_READONLY(trace_maglev_phi_untagging, false,
"trace maglev phi untagging")
DEFINE_BOOL_READONLY(trace_maglev_regalloc, false,
"trace maglev register allocation")
#endif // V8_ENABLE_MAGLEV_GRAPH_PRINTER
DEFINE_BOOL(maglev_stats, false, "print Maglev statistics")
DEFINE_BOOL(maglev_stats_nvp, false,
"print Maglev statistics in machine-readable format")
// TODO(v8:7700): Remove once stable.
DEFINE_BOOL(maglev_function_context_specialization, true,
"enable function context specialization in maglev")
DEFINE_BOOL(maglev_skip_migration_check_for_polymorphic_access, false,
"skip generating a migration check when some maps of polymorpic "
"property access are migration targets")
#ifdef V8_ENABLE_SPARKPLUG
DEFINE_WEAK_IMPLICATION(future, flush_baseline_code)
#endif
DEFINE_BOOL(
enable_enumerated_keyed_access_bytecode, true,
"enable generating GetEnumeratedKeyedProperty bytecode for keyed access")
DEFINE_BOOL_READONLY(dict_property_const_tracking,
V8_DICT_PROPERTY_CONST_TRACKING_BOOL,
"Use const tracking on dictionary properties")
DEFINE_BOOL(const_tracking_let, true,
"Use const tracking on top-level `let` variables")
DEFINE_BOOL(script_context_mutable_heap_number, true,
"Use mutable heap numbers in script contexts")
#if defined(V8_31BIT_SMIS_ON_64BIT_ARCH) || defined(V8_TARGET_ARCH_32_BIT)
#define SUPPORT_SCRIPT_CONTEXT_MUTABLE_HEAP_INT32
DEFINE_BOOL(script_context_mutable_heap_int32, true,
"Use mutable heap int32 number in script contexts")
DEFINE_WEAK_IMPLICATION(script_context_mutable_heap_int32,
script_context_mutable_heap_number)
#else
DEFINE_BOOL_READONLY(script_context_mutable_heap_int32, false,
"Use mutable heap int32 number in script contexts")
#endif
DEFINE_BOOL(empty_context_extension_dep, true,
"Use compilation dependency to avoid dynamic checks for "
"non-empty context extensions")
DEFINE_BOOL(json_stringify_fast_path, false, "Enable JSON.stringify fast-path")
DEFINE_WEAK_IMPLICATION(future, json_stringify_fast_path)
#ifdef V8_ENABLE_EXTENSIBLE_RO_SNAPSHOT
DEFINE_BOOL(extensible_ro_snapshot, true,
"Whether custom embedder snapshots may extend ReadOnlySpace")
#else
DEFINE_BOOL_READONLY(
extensible_ro_snapshot, false,
"Whether custom embedder snapshots may extend ReadOnlySpace")
#endif // V8_ENABLE_EXTENSIBLE_RO_SNAPSHOT
DEFINE_UINT(max_opt, 999,
"Set the maximal optimisation tier: "
"> 3 == any, 0 == ignition/interpreter, 1 == sparkplug/baseline, "
"2 == maglev, 3 == turbofan")
#ifdef V8_ENABLE_TURBOFAN
DEFINE_WEAK_VALUE_IMPLICATION(max_opt < 3, turbofan, false)
#endif // V8_ENABLE_TURBOFAN
#ifdef V8_ENABLE_MAGLEV
DEFINE_WEAK_VALUE_IMPLICATION(max_opt < 2, maglev, false)
#endif // V8_ENABLE_MAGLEV
#ifdef V8_ENABLE_SPARKPLUG
DEFINE_WEAK_VALUE_IMPLICATION(max_opt < 1, sparkplug, false)
#endif // V8_ENABLE_SPARKPLUG
// Flags to override efficiency and battery saver mode settings for debugging
// and testing.
DEFINE_MAYBE_BOOL(efficiency_mode,
"Forces efficiency mode on or off, disregarding any dynamic "
"signals. Efficiency mode is optimized for situations with "
"no latency requirements and uses fewer threads.")
DEFINE_MAYBE_BOOL(
battery_saver_mode,
"Forces battery saver mode on or off, disregarding any dynamic signals. "
"Battery saver tries to conserve overal cpu cycles spent.")
DEFINE_MAYBE_BOOL(
memory_saver_mode,
"Forces memory saver mode on or off, disregarding any dynamic signals. "
"Memory saver tries to keep memory footprint low at the expense of extra "
"cpu cycles.")
// Flags to experiment with the new efficiency mode
DEFINE_BOOL(efficiency_mode_for_tiering_heuristics, true,
"Use efficiency mode in tiering heuristics.")
DEFINE_BOOL(efficiency_mode_disable_turbofan, false,
"Defer tier-up to turbofan while in efficiency mode.")
DEFINE_INT(efficiency_mode_delay_turbofan, 15000,
"Delay tier-up to turbofan to a certain invocation count while in "
"efficiency mode.")
// Flag to select wasm trace mark type
DEFINE_STRING(
wasm_trace_native, nullptr,
"Select which native code sequence to use for wasm trace instruction: "
"default or cpuid")
#ifdef V8_JITLESS
#define V8_JITLESS_BOOL true
DEFINE_BOOL_READONLY(jitless, true,
"Disable runtime allocation of executable memory.")
#else
#define V8_JITLESS_BOOL false
DEFINE_BOOL(jitless, V8_LITE_MODE_BOOL,
"Disable runtime allocation of executable memory.")
#endif // V8_JITLESS
// Jitless V8 has a few implications:
// Field type tracking is only used by TurboFan.
DEFINE_NEG_IMPLICATION(jitless, track_field_types)
DEFINE_NEG_IMPLICATION(jitless, script_context_mutable_heap_number)
// No code generation at runtime.
DEFINE_IMPLICATION(jitless, regexp_interpret_all)
DEFINE_NEG_IMPLICATION(jitless, turbofan)
#ifdef V8_ENABLE_SPARKPLUG
DEFINE_NEG_IMPLICATION(jitless, sparkplug)
DEFINE_NEG_IMPLICATION(jitless, always_sparkplug)
#endif // V8_ENABLE_SPARKPLUG
#ifdef V8_ENABLE_MAGLEV
DEFINE_NEG_IMPLICATION(jitless, maglev)
#endif // V8_ENABLE_MAGLEV
// Doesn't work without an executable code space.
DEFINE_NEG_IMPLICATION(jitless, interpreted_frames_native_stack)
DEFINE_BOOL(
disable_optimizing_compilers, false,
"Disable all optimizing compilers while leaving baseline compilers enabled")
// Disable all optimizing JavaScript compilers.
// JavaScript code can execute either in Ignition or Sparkplug.
DEFINE_NEG_IMPLICATION(disable_optimizing_compilers, turbofan)
DEFINE_NEG_IMPLICATION(disable_optimizing_compilers, turboshaft)
DEFINE_NEG_IMPLICATION(disable_optimizing_compilers, maglev)
#if V8_ENABLE_WEBASSEMBLY
// Disable optimizing Wasm compilers. Wasm code must execute with Liftoff.
DEFINE_IMPLICATION(disable_optimizing_compilers, liftoff)
DEFINE_NEG_IMPLICATION(disable_optimizing_compilers, wasm_tier_up)
DEFINE_NEG_IMPLICATION(disable_optimizing_compilers, wasm_dynamic_tiering)
// Disable translation of asm.js to Wasm
DEFINE_NEG_IMPLICATION(disable_optimizing_compilers, validate_asm)
#endif // V8_ENABLE_WEBASSEMBLY
// Field type tracking is only used by TurboFan, so can be disabled.
DEFINE_NEG_IMPLICATION(disable_optimizing_compilers, track_field_types)
DEFINE_NEG_IMPLICATION(disable_optimizing_compilers,
script_context_mutable_heap_number)
DEFINE_BOOL(memory_protection_keys, true,
"protect code memory with PKU if available")
DEFINE_BOOL(assert_types, false,
"generate runtime type assertions to test the typer")
// TODO(tebbi): Support allocating types from background thread.
DEFINE_NEG_IMPLICATION(assert_types, concurrent_recompilation)
DEFINE_NEG_IMPLICATION(assert_types, concurrent_builtin_generation)
DEFINE_EXPERIMENTAL_FEATURE(
turboshaft_assert_types,
"generate runtime type assertions to test the turboshaft type system")
DEFINE_NEG_IMPLICATION(turboshaft_assert_types, concurrent_recompilation)
DEFINE_NEG_IMPLICATION(turboshaft_assert_types, concurrent_builtin_generation)
// Enable verification of SimplifiedLowering in debug builds.
DEFINE_BOOL(verify_simplified_lowering, DEBUG_BOOL,
"verify graph generated by simplified lowering")
DEFINE_BOOL(trace_compilation_dependencies, false, "trace code dependencies")
// Depend on --trace-deopt-verbose for reporting dependency invalidations.
DEFINE_IMPLICATION(trace_compilation_dependencies, trace_deopt_verbose)
#ifdef V8_ALLOCATION_SITE_TRACKING
#define V8_ALLOCATION_SITE_TRACKING_BOOL true
#else
#define V8_ALLOCATION_SITE_TRACKING_BOOL false
#endif
DEFINE_BOOL_READONLY(allocation_site_tracking, V8_ALLOCATION_SITE_TRACKING_BOOL,
"Enable allocation site tracking")
DEFINE_NEG_NEG_IMPLICATION(allocation_site_tracking,
allocation_site_pretenuring)
// Flags for experimental implementation features.
DEFINE_BOOL(allocation_site_pretenuring, true,
"pretenure with allocation sites")
DEFINE_BOOL(page_promotion, true, "promote pages based on utilization")
DEFINE_INT(page_promotion_threshold, 70,
"min percentage of live bytes on a page to enable fast evacuation "
"in full GCs")
DEFINE_INT(minor_ms_page_promotion_threshold, 50,
"min percentage of live bytes on a page to enable fast evacuation "
"in MinorMS")
DEFINE_INT(minor_ms_page_promotion_max_lab_threshold, 30,
"max percentage of labs out of a page to still be considered for "
"page promotion")
DEFINE_UINT(minor_ms_max_page_age, 4,
"max age for a page after which it is force promoted to old space")
DEFINE_UINT(minor_ms_max_new_space_capacity_mb, 72,
"max new space capacity in MBs when using MinorMS. When pointer "
"compression is disabled, twice the capacity is used.")
DEFINE_REQUIREMENT(v8_flags.minor_ms_max_new_space_capacity_mb > 0)
#if defined(ANDROID)
#define DEFAULT_SCAVENGER_MAX_NEW_SPACE_CAPACITY_MB 8
#else
#define DEFAULT_SCAVENGER_MAX_NEW_SPACE_CAPACITY_MB 32
#endif
DEFINE_UINT(scavenger_max_new_space_capacity_mb,
DEFAULT_SCAVENGER_MAX_NEW_SPACE_CAPACITY_MB,
"max new space capacity in MBs when using Scavenger. When pointer "
"compression is disabled, twice the capacity is used.")
DEFINE_REQUIREMENT(v8_flags.scavenger_max_new_space_capacity_mb > 0)
#undef DEFAULT_SCAVENGER_MAX_NEW_SPACE_CAPACITY_MB
DEFINE_BOOL(trace_page_promotions, false, "trace page promotion decisions")
DEFINE_BOOL(trace_pretenuring, false,
"trace pretenuring decisions of HAllocate instructions")
DEFINE_BOOL(trace_pretenuring_statistics, false,
"trace allocation site pretenuring statistics")
DEFINE_BOOL(track_field_types, true, "track field types")
DEFINE_BOOL(trace_block_coverage, false,
"trace collected block coverage information")
DEFINE_BOOL(trace_protector_invalidation, false,
"trace protector cell invalidations")
DEFINE_BOOL(decommit_pooled_pages, true,
"decommit, rather than discard pooled pages")
DEFINE_BOOL(
zero_unused_memory, false,
"Zero unused memory (except for memory which was discarded) on memory "
"reducing GCs.")
#ifdef V8_MINORMS_STRING_SHORTCUTTING
DEFINE_BOOL(minor_ms_shortcut_strings, false,
"short cut strings during marking")
// String shortcutting currently doesn't work with concurrent marking.
DEFINE_NEG_IMPLICATION(minor_ms_shortcut_strings, concurrent_minor_ms_marking)
#else
DEFINE_BOOL_READONLY(minor_ms_shortcut_strings, false,
"short cut strings during marking")
#endif
DEFINE_EXPERIMENTAL_FEATURE(feedback_normalization,
"feed back normalization to constructors")
// TODO(jkummerow): This currently adds too much load on the stub cache.
DEFINE_BOOL_READONLY(internalize_on_the_fly, true,
"internalize string keys for generic keyed ICs on the fly")
// Flag for sealed, frozen elements kind instead of dictionary elements kind
DEFINE_BOOL_READONLY(enable_sealed_frozen_elements_kind, true,
"Enable sealed, frozen elements kind")
// Flags for data representation optimizations
DEFINE_BOOL(unbox_double_arrays, true, "automatically unbox arrays of doubles")
DEFINE_BOOL_READONLY(string_slices, true, "use string slices")
// Tiering: Sparkplug / feedback vector allocation.
DEFINE_INT(invocation_count_for_feedback_allocation, 8,
"invocation count required for allocating feedback vectors")
// Tiering: Maglev.
#if defined(ANDROID)
DEFINE_INT(invocation_count_for_maglev, 1000,
"invocation count required for optimizing with Maglev")
#else
DEFINE_INT(invocation_count_for_maglev, 400,
"invocation count required for optimizing with Maglev")
#endif // ANDROID
DEFINE_INT(invocation_count_for_maglev_osr, 100,
"invocation count required for maglev OSR")
DEFINE_BOOL(osr_from_maglev, false,
"whether we try to OSR to Turbofan from OSR'd Maglev")
DEFINE_FLOAT(
osr_from_maglev_interrupt_scale_factor, 0.8,
"Scale interrupt budget reduction for OSR from Maglev vs. OSR to Maglev")
DEFINE_BOOL(always_osr_from_maglev, false,
"whether we try to OSR to Turbofan from any Maglev")
DEFINE_VALUE_IMPLICATION(always_osr_from_maglev, osr_from_maglev, true)
// Tiering: Turbofan.
DEFINE_INT(invocation_count_for_turbofan, 3000,
"invocation count required for optimizing with TurboFan")
DEFINE_INT(invocation_count_for_osr, 500, "invocation count required for OSR")
DEFINE_INT(osr_to_tierup, 1,
"number to decrease the invocation budget by when we follow OSR")
DEFINE_INT(minimum_invocations_after_ic_update, 500,
"How long to minimally wait after IC update before tier up")
DEFINE_INT(minimum_invocations_before_optimization, 2,
"Minimum number of invocations we need before non-OSR optimization")
// Tiering: JIT fuzzing.
//
// When --jit-fuzzing is enabled, various tiering related thresholds are
// lowered so that the different JIT tiers are reached roughly within a few
// dozen executions of the code instead of a few hundred or thousand. As a rule
// of thumb, aiming for things to happen 5x to 10x sooner in this mode than
// they otherwise would is probably not unreasonable.
DEFINE_BOOL(jit_fuzzing, false,
"Set JIT tiering thresholds suitable for JIT fuzzing")
// Tier up to Sparkplug should happen after a handful o executions in ignition.
DEFINE_NEG_IMPLICATION(jit_fuzzing, lazy_feedback_allocation)
DEFINE_NEG_IMPLICATION(jit_fuzzing, baseline_batch_compilation)
// Tier up to Maglev should happen soon afterwards.
DEFINE_VALUE_IMPLICATION(jit_fuzzing, invocation_count_for_maglev, 10)
// And tier up to Turbofan should happen after a couple dozen or so executions.
DEFINE_VALUE_IMPLICATION(jit_fuzzing, invocation_count_for_turbofan, 20)
// Additionally, some other JIT-related thresholds should also be lowered.
DEFINE_VALUE_IMPLICATION(jit_fuzzing, invocation_count_for_osr, 5)
DEFINE_VALUE_IMPLICATION(jit_fuzzing, invocation_count_for_maglev_osr, 1)
DEFINE_VALUE_IMPLICATION(jit_fuzzing, minimum_invocations_after_ic_update, 5)
#if V8_ENABLE_WEBASSEMBLY
// Wasm tiering thresholds.
DEFINE_VALUE_IMPLICATION(jit_fuzzing, wasm_wrapper_tiering_budget, 1)
DEFINE_VALUE_IMPLICATION(jit_fuzzing, wasm_tiering_budget, 1)
DEFINE_IMPLICATION(jit_fuzzing, wasm_inlining_ignore_call_counts)
#endif // V8_ENABLE_WEBASSEMBLY
DEFINE_BOOL(use_std_math_pow, true,
"use std::pow instead of our custom implementation")
// Flags for inline caching and feedback vectors.
DEFINE_BOOL(use_ic, true, "use inline caching")
DEFINE_BOOL(lazy_feedback_allocation, true, "Allocate feedback vectors lazily")
DEFINE_BOOL(stress_ic, false, "exercise interesting paths in ICs more often")
// Flags for Ignition.
DEFINE_BOOL(ignition_elide_noneffectful_bytecodes, true,
"elide bytecodes which won't have any external effect")
DEFINE_BOOL(ignition_reo, true, "use ignition register equivalence optimizer")
DEFINE_BOOL(ignition_filter_expression_positions, true,
"filter expression positions before the bytecode pipeline")
DEFINE_BOOL(ignition_share_named_property_feedback, true,
"share feedback slots when loading the same named property from "
"the same object")
DEFINE_BOOL(ignition_elide_redundant_tdz_checks, true,
"elide TDZ checks dominated by other TDZ checks")
DEFINE_BOOL(print_bytecode, false,
"print bytecode generated by ignition interpreter")
DEFINE_BOOL(enable_lazy_source_positions, V8_LAZY_SOURCE_POSITIONS_BOOL,
"skip generating source positions during initial compile but "
"regenerate when actually required")
DEFINE_BOOL(stress_lazy_source_positions, false,
"collect lazy source positions immediately after lazy compile")
DEFINE_STRING(print_bytecode_filter, "*",
"filter for selecting which functions to print bytecode")
DEFINE_BOOL(omit_default_ctors, true, "omit calling default ctors in bytecode")
#ifdef V8_TRACE_UNOPTIMIZED
DEFINE_BOOL(trace_unoptimized, false,
"trace the bytecodes executed by all unoptimized execution")
DEFINE_BOOL(trace_ignition, false,
"trace the bytecodes executed by the ignition interpreter")
DEFINE_BOOL(trace_baseline_exec, false,
"trace the bytecodes executed by the baseline code")
DEFINE_WEAK_IMPLICATION(trace_unoptimized, trace_ignition)
DEFINE_WEAK_IMPLICATION(trace_unoptimized, trace_baseline_exec)
#endif
#ifdef V8_TRACE_FEEDBACK_UPDATES
DEFINE_BOOL(
trace_feedback_updates, false,
"trace updates to feedback vectors during ignition interpreter execution.")
#endif
DEFINE_BOOL(trace_ignition_codegen, false,
"trace the codegen of ignition interpreter bytecode handlers")
DEFINE_STRING(
trace_ignition_dispatches_output_file, nullptr,
"write the bytecode handler dispatch table to the specified file (d8 only) "
"(requires building with v8_enable_ignition_dispatch_counting)")
DEFINE_BOOL(trace_track_allocation_sites, false,
"trace the tracking of allocation sites")
DEFINE_BOOL(trace_migration, false, "trace object migration")
DEFINE_BOOL(trace_generalization, false, "trace map generalization")
// Flags for Sparkplug
#undef FLAG
#if V8_ENABLE_SPARKPLUG
#define FLAG FLAG_FULL
#else
#define FLAG FLAG_READONLY
#endif
DEFINE_BOOL(sparkplug, ENABLE_SPARKPLUG_BY_DEFAULT,
"enable Sparkplug baseline compiler")
DEFINE_BOOL(always_sparkplug, false, "directly tier up to Sparkplug code")
#if V8_ENABLE_SPARKPLUG
DEFINE_IMPLICATION(always_sparkplug, sparkplug)
DEFINE_BOOL(baseline_batch_compilation, true, "batch compile Sparkplug code")
#if defined(V8_OS_DARWIN) && defined(V8_HOST_ARCH_ARM64) && \
!V8_HEAP_USE_PTHREAD_JIT_WRITE_PROTECT && \
!V8_HEAP_USE_BECORE_JIT_WRITE_PROTECT
// M1 requires W^X.
DEFINE_BOOL_READONLY(concurrent_sparkplug, false,
"compile Sparkplug code in a background thread")
#else
DEFINE_BOOL(concurrent_sparkplug, ENABLE_SPARKPLUG_BY_DEFAULT,
"compile Sparkplug code in a background thread")
DEFINE_WEAK_IMPLICATION(future, concurrent_sparkplug)
DEFINE_NEG_IMPLICATION(predictable, concurrent_sparkplug)
DEFINE_NEG_IMPLICATION(single_threaded, concurrent_sparkplug)
DEFINE_NEG_IMPLICATION(jitless, concurrent_sparkplug)
#endif
DEFINE_UINT(
concurrent_sparkplug_max_threads, 1,
"max number of threads that concurrent Sparkplug can use (0 for unbounded)")
DEFINE_BOOL(concurrent_sparkplug_high_priority_threads, false,
"use high priority compiler threads for concurrent Sparkplug")
#else
DEFINE_BOOL(baseline_batch_compilation, false, "batch compile Sparkplug code")
DEFINE_BOOL_READONLY(concurrent_sparkplug, false,
"compile Sparkplug code in a background thread")
#endif
DEFINE_STRING(sparkplug_filter, "*", "filter for Sparkplug baseline compiler")
DEFINE_BOOL(sparkplug_needs_short_builtins, false,
"only enable Sparkplug baseline compiler when "
"--short-builtin-calls are also enabled")
DEFINE_INT(baseline_batch_compilation_threshold, 4 * KB,
"the estimated instruction size of a batch to trigger compilation")
DEFINE_BOOL(trace_baseline, false, "trace baseline compilation")
DEFINE_BOOL(trace_baseline_batch_compilation, false,
"trace baseline batch compilation")
DEFINE_WEAK_IMPLICATION(trace_baseline, trace_baseline_batch_compilation)
#undef FLAG
#define FLAG FLAG_FULL
// Internalize into a shared string table in the shared isolate
DEFINE_BOOL(shared_string_table, false, "internalize strings into shared table")
DEFINE_IMPLICATION(harmony_struct, shared_string_table)
DEFINE_IMPLICATION(shared_string_table, shared_heap)
DEFINE_BOOL_READONLY(always_use_string_forwarding_table, false,
"use string forwarding table instead of thin strings for "
"all strings (experimental)")
DEFINE_IMPLICATION(always_use_string_forwarding_table, experimental)
// With --always-use-string-forwarding-table, we can have young generation
// string entries in the forwarding table, requiring table updates when these
// strings get promoted to old space. Parallel GCs in client isolates
// (enabled by --shared-string-table) are not supported using a single shared
// forwarding table.
DEFINE_NEG_IMPLICATION(shared_string_table, always_use_string_forwarding_table)
DEFINE_BOOL(transition_strings_during_gc_with_stack, false,
"Transition strings during a full GC with stack")
DEFINE_SIZE_T(initial_shared_heap_size, 0,
"initial size of the shared heap (in Mbytes); "
"other heap size flags (e.g. initial_heap_size) take precedence")
DEFINE_SIZE_T(
max_shared_heap_size, 0,
"max size of the shared heap (in Mbytes); "
"other heap size flags (e.g. max_shared_heap_size) take precedence")
DEFINE_BOOL(concurrent_builtin_generation, false,
"generate builtins concurrently on separate threads in mksnapshot")
// Flags for concurrent recompilation.
DEFINE_BOOL(concurrent_recompilation, true,
"optimizing hot functions asynchronously on a separate thread")
DEFINE_BOOL(trace_concurrent_recompilation, false,
"track concurrent recompilation")
DEFINE_INT(concurrent_recompilation_queue_length, 8,
"the length of the concurrent compilation queue")
DEFINE_INT(concurrent_recompilation_delay, 0,
"artificial compilation delay in ms")
DEFINE_BOOL(concurrent_recompilation_front_running, true,
"move compile jobs to the front if recompilation is requested "
"multiple times")
DEFINE_UINT(
concurrent_turbofan_max_threads, 4,
"max number of threads that concurrent Turbofan can use (0 for unbounded)")
DEFINE_BOOL(
stress_concurrent_inlining, false,
"create additional concurrent optimization jobs but throw away result")
DEFINE_IMPLICATION(stress_concurrent_inlining, concurrent_recompilation)
DEFINE_IMPLICATION(stress_concurrent_inlining, turbofan)
DEFINE_NEG_IMPLICATION(stress_concurrent_inlining, lazy_feedback_allocation)
DEFINE_WEAK_VALUE_IMPLICATION(stress_concurrent_inlining,
invocation_count_for_turbofan, 150)
DEFINE_BOOL(maglev_overwrite_budget, false,
"whether maglev resets the interrupt budget")
DEFINE_WEAK_IMPLICATION(maglev, maglev_overwrite_budget)
DEFINE_NEG_IMPLICATION(stress_concurrent_inlining, maglev_overwrite_budget)
DEFINE_WEAK_VALUE_IMPLICATION(maglev_overwrite_budget,
invocation_count_for_turbofan, 6000)
DEFINE_BOOL(maglev_overwrite_osr_budget, false,
"whether maglev resets the OSR interrupt budget")
DEFINE_WEAK_IMPLICATION(maglev_osr, maglev_overwrite_osr_budget)
DEFINE_NEG_IMPLICATION(stress_concurrent_inlining, maglev_overwrite_osr_budget)
DEFINE_WEAK_VALUE_IMPLICATION(maglev_overwrite_osr_budget,
invocation_count_for_osr, 800)
DEFINE_BOOL(stress_concurrent_inlining_attach_code, false,
"create additional concurrent optimization jobs")
DEFINE_IMPLICATION(stress_concurrent_inlining_attach_code,
stress_concurrent_inlining)
DEFINE_INT(max_serializer_nesting, 25,
"maximum levels for nesting child serializers")
DEFINE_BOOL(trace_heap_broker_verbose, false,
"trace the heap broker verbosely (all reports)")
DEFINE_BOOL(trace_heap_broker, false,
"trace the heap broker (reports on missing data only)")
DEFINE_IMPLICATION(trace_heap_broker_verbose, trace_heap_broker)
DEFINE_IMPLICATION(trace_heap_broker, trace_pending_allocations)
// Flags for stress-testing the compiler.
DEFINE_INT(stress_runs, 0, "number of stress runs")
DEFINE_INT(deopt_every_n_times, 0,
"deoptimize every n times a deopt point is passed")
DEFINE_BOOL(print_deopt_stress, false, "print number of possible deopt points")
// Flags for TurboFan.
#ifdef V8_ENABLE_TURBOFAN
#define V8_ENABLE_TURBOFAN_BOOL true
DEFINE_BOOL(turbofan, true, "use the Turbofan optimizing compiler")
// TODO(leszeks): Temporary alias until we make sure all our infra is passing
// --turbofan instead of --opt.
DEFINE_ALIAS_BOOL(opt, turbofan)
#else
#define V8_ENABLE_TURBOFAN_BOOL false
DEFINE_BOOL_READONLY(turbofan, false, "use the Turbofan optimizing compiler")
DEFINE_BOOL_READONLY(opt, false, "use the Turbofan optimizing compiler")
#endif // V8_ENABLE_TURBOFAN
DEFINE_BOOL(
stress_turbo_late_spilling, false,
"optimize placement of all spill instructions, not just loop-top phis")
DEFINE_BOOL(turbo_wasm_address_reassociation, true,
"refactor address components for immediate indexing")
DEFINE_STRING(turbo_filter, "*", "optimization filter for TurboFan compiler")
DEFINE_BOOL(trace_turbo, false, "trace generated TurboFan IR")
DEFINE_NEG_IMPLICATION(trace_turbo, concurrent_builtin_generation)
DEFINE_STRING(trace_turbo_path, nullptr,
"directory to dump generated TurboFan IR to")
DEFINE_STRING(trace_turbo_filter, "*",
"filter for tracing turbofan compilation")
DEFINE_BOOL(trace_turbo_graph, false, "trace generated TurboFan graphs")
DEFINE_NEG_IMPLICATION(trace_turbo_graph, concurrent_builtin_generation)
DEFINE_BOOL(trace_turbo_scheduled, false, "trace TurboFan IR with schedule")
DEFINE_IMPLICATION(trace_turbo_scheduled, trace_turbo_graph)
DEFINE_STRING(trace_turbo_file_prefix, "turbo",
"trace turbo graph to a file with given prefix")
DEFINE_STRING(trace_turbo_cfg_file, nullptr,
"trace turbo cfg graph (for C1 visualizer) to a given file name")
DEFINE_BOOL(trace_turbo_types, true, "trace TurboFan's types")
DEFINE_BOOL(trace_turbo_scheduler, false, "trace TurboFan's scheduler")
DEFINE_BOOL(trace_turbo_reduction, false, "trace TurboFan's various reducers")
#ifdef V8_ENABLE_SLOW_TRACING
#define DEFINE_SLOW_TRACING_BOOL DEFINE_BOOL
#else
#define DEFINE_SLOW_TRACING_BOOL DEFINE_BOOL_READONLY
#endif // V8_ENABLE_SLOW_TRACING
DEFINE_SLOW_TRACING_BOOL(trace_turbo_trimming, false,
"trace TurboFan's graph trimmer")
DEFINE_SLOW_TRACING_BOOL(trace_turbo_jt, false,
"trace TurboFan's jump threading")
DEFINE_SLOW_TRACING_BOOL(trace_turbo_ceq, false,
"trace TurboFan's control equivalence")
DEFINE_SLOW_TRACING_BOOL(trace_turbo_loop, false,
"trace TurboFan's loop optimizations")
DEFINE_SLOW_TRACING_BOOL(trace_turbo_alloc, false,
"trace TurboFan's register allocator")
DEFINE_SLOW_TRACING_BOOL(trace_all_uses, false, "trace all use positions")
DEFINE_SLOW_TRACING_BOOL(trace_representation, false,
"trace representation types")
DEFINE_BOOL(
trace_turbo_stack_accesses, false,
"trace stack load/store counters for optimized code in run-time (x64 only)")
// When fuzzing and concurrent compilation is enabled, disable Turbofan
// tracing flags since reading/printing heap state is not thread-safe and
// leads to false positives on TSAN bots.
// TODO(chromium:1205289): Teach relevant fuzzers to not pass TF tracing
// flags instead, and remove this section.
DEFINE_BOOL(fuzzing_and_concurrent_recompilation, true,
"fuzzing && concurrent_recompilation")
DEFINE_NEG_NEG_IMPLICATION(fuzzing, fuzzing_and_concurrent_recompilation)
DEFINE_NEG_NEG_IMPLICATION(concurrent_recompilation,
fuzzing_and_concurrent_recompilation)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo_graph)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo_scheduled)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo_reduction)
#ifdef V8_ENABLE_SLOW_TRACING
// If expensive tracing is disabled via a build flag, the following flags
// cannot be disabled (because they are already).
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo_trimming)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo_jt)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo_ceq)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo_loop)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo_alloc)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_all_uses)
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_representation)
#endif
DEFINE_DISABLE_FLAG_IMPLICATION(fuzzing_and_concurrent_recompilation,
trace_turbo_stack_accesses)
DEFINE_BOOL(turbo_verify, DEBUG_BOOL, "verify TurboFan graphs at each phase")
DEFINE_STRING(turbo_verify_machine_graph, nullptr,
"verify TurboFan machine graph before instruction selection")
#ifdef ENABLE_VERIFY_CSA
DEFINE_BOOL(verify_csa, DEBUG_BOOL,
"verify TurboFan machine graph of code stubs")
#else
// Define the flag as read-only-false so that code still compiles even in the
// non-ENABLE_VERIFY_CSA configuration.
DEFINE_BOOL_READONLY(verify_csa, false,
"verify TurboFan machine graph of code stubs")
#endif // ENABLE_VERIFY_CSA
DEFINE_BOOL(trace_verify_csa, false, "trace code stubs verification")
DEFINE_STRING(csa_trap_on_node, nullptr,
"trigger break point when a node with given id is created in "
"given stub. The format is: StubName,NodeId")
DEFINE_BOOL_READONLY(fixed_array_bounds_checks, true,
"enable FixedArray bounds checks")
DEFINE_BOOL(turbo_stats, false, "print TurboFan statistics")
DEFINE_BOOL(turbo_stats_nvp, false,
"print TurboFan statistics in machine-readable format")
DEFINE_BOOL(turbo_stats_wasm, false,
"print TurboFan statistics of wasm compilations")
DEFINE_BOOL(turbo_splitting, true, "split nodes during scheduling in TurboFan")
DEFINE_BOOL(turbo_inlining, true, "enable inlining in TurboFan")
DEFINE_INT(max_inlined_bytecode_size, 460,
"maximum size of bytecode for a single inlining")
DEFINE_INT(max_inlined_bytecode_size_cumulative, 920,
"maximum cumulative size of bytecode considered for inlining")
DEFINE_INT(max_inlined_bytecode_size_absolute, 4600,
"maximum absolute size of bytecode considered for inlining")
DEFINE_FLOAT(
reserve_inline_budget_scale_factor, 1.2,
"scale factor of bytecode size used to calculate the inlining budget")
DEFINE_INT(max_inlined_bytecode_size_small, 27,
"maximum size of bytecode considered for small function inlining")
DEFINE_INT(max_optimized_bytecode_size, 60 * KB,
"maximum bytecode size to "
"be considered for turbofan optimization; too high values may cause "
"the compiler to hit (release) assertions")
DEFINE_FLOAT(min_inlining_frequency, 0.15, "minimum frequency for inlining")
DEFINE_BOOL(polymorphic_inlining, true, "polymorphic inlining")
DEFINE_BOOL(stress_inline, false,
"set high thresholds for inlining to inline as much as possible")
DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size, 999999)
DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_cumulative,
999999)
DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_absolute,
999999)
DEFINE_VALUE_IMPLICATION(stress_inline, min_inlining_frequency, 0.)
DEFINE_IMPLICATION(stress_inline, polymorphic_inlining)
DEFINE_BOOL(trace_turbo_inlining, false, "trace TurboFan inlining")
DEFINE_BOOL(turbo_inline_array_builtins, true,
"inline array builtins in TurboFan code")
DEFINE_BOOL(use_osr, true, "use on-stack replacement")
DEFINE_BOOL(maglev_osr, true, "use maglev as on-stack replacement target")
// When using maglev as OSR target allow us to tier up further
DEFINE_WEAK_VALUE_IMPLICATION(maglev_osr, osr_from_maglev, true)
DEFINE_NEG_VALUE_IMPLICATION(use_osr, maglev_osr, false)
DEFINE_NEG_VALUE_IMPLICATION(turbofan, osr_from_maglev, false)
DEFINE_BOOL(concurrent_osr, true, "enable concurrent OSR")
DEFINE_BOOL(maglev_escape_analysis, true,
"avoid inlined allocation of objects that cannot escape")
DEFINE_BOOL(trace_maglev_escape_analysis, false, "trace maglev escape analysis")
DEFINE_EXPERIMENTAL_FEATURE(maglev_object_tracking,
"track object changes to avoid escaping them")
DEFINE_WEAK_IMPLICATION(maglev_future, maglev_object_tracking)
DEFINE_BOOL(trace_maglev_object_tracking, false,
"trace load/stores from maglev virtual objects")
DEFINE_WEAK_IMPLICATION(trace_maglev_graph_building,
trace_maglev_object_tracking)
// TODO(dmercadier): fix and re-enable string builder.
DEFINE_BOOL_READONLY(turbo_string_builder, false,
"use TurboFan fast string builder")
DEFINE_BOOL(trace_osr, false, "trace on-stack replacement")
DEFINE_BOOL(log_or_trace_osr, false,
"internal helper flag, please use --trace-osr instead.")
DEFINE_IMPLICATION(trace_osr, log_or_trace_osr)
DEFINE_IMPLICATION(log_function_events, log_or_trace_osr)
DEFINE_BOOL(analyze_environment_liveness, true,
"analyze liveness of environment slots and zap dead values")
DEFINE_BOOL(trace_environment_liveness, false,
"trace liveness of local variable slots")
DEFINE_BOOL(turbo_load_elimination, true, "enable load elimination in TurboFan")
DEFINE_BOOL(trace_turbo_load_elimination, false,
"trace TurboFan load elimination")
DEFINE_BOOL(turbo_profiling, false, "enable basic block profiling in TurboFan")
DEFINE_NEG_IMPLICATION(turbo_profiling, concurrent_builtin_generation)
DEFINE_BOOL(turbo_profiling_verbose, false,
"enable basic block profiling in TurboFan, and include each "
"function's schedule and disassembly in the output")
DEFINE_IMPLICATION(turbo_profiling_verbose, turbo_profiling)
DEFINE_STRING(
turbo_profiling_output, nullptr,
"emit data about basic block usage in builtins to this file "
"(requires that V8 was built with v8_enable_builtins_profiling=true)")
DEFINE_BOOL(reorder_builtins, false,
"enable builtin reordering when run mksnapshot.")
DEFINE_NEG_IMPLICATION(reorder_builtins, concurrent_builtin_generation)
DEFINE_BOOL(abort_on_bad_builtin_profile_data, false,
"flag for mksnapshot, abort if builtins profile can't be applied")
DEFINE_BOOL(
warn_about_builtin_profile_data, false,
"flag for mksnapshot, emit warnings when applying builtin profile data")
DEFINE_STRING(
dump_builtins_hashes_to_file, nullptr,
"flag for mksnapshot, dump CSA builtins graph hashes to this file")
DEFINE_BOOL(turbo_verify_allocation, DEBUG_BOOL,
"verify register allocation in TurboFan")
DEFINE_BOOL(turbo_move_optimization, true, "optimize gap moves in TurboFan")
DEFINE_BOOL(turbo_jt, true, "enable jump threading in TurboFan")
DEFINE_BOOL(turbo_loop_peeling, true, "TurboFan loop peeling")
DEFINE_BOOL(turbo_loop_variable, true, "TurboFan loop variable optimization")
DEFINE_BOOL(turbo_loop_rotation, true, "TurboFan loop rotation")
DEFINE_BOOL(turbo_cf_optimization, true, "optimize control flow in TurboFan")
DEFINE_BOOL(turbo_escape, true, "enable escape analysis")
DEFINE_BOOL(turbo_allocation_folding, true, "TurboFan allocation folding")
DEFINE_BOOL(turbo_instruction_scheduling, false,
"enable instruction scheduling in TurboFan")
DEFINE_BOOL(turbo_stress_instruction_scheduling, false,
"randomly schedule instructions to stress dependency tracking")
DEFINE_IMPLICATION(turbo_stress_instruction_scheduling,
turbo_instruction_scheduling)
DEFINE_BOOL(turbo_store_elimination, true,
"enable store-store elimination in TurboFan")
DEFINE_BOOL(trace_store_elimination, false, "trace store elimination")
DEFINE_BOOL_READONLY(turbo_typer_hardening, true,
"extra bounds checks to protect against some known typer "
"mismatch exploit techniques (best effort)")
#if defined(V8_TARGET_ARCH_X64) || defined(V8_TARGET_ARCH_IA32)
DEFINE_BOOL(turbo_rewrite_far_jumps, true,
"rewrite far to near jumps (ia32,x64)")
#else
DEFINE_BOOL_READONLY(turbo_rewrite_far_jumps, false,
"rewrite far to near jumps (ia32,x64)")
#endif
DEFINE_BOOL(
stress_gc_during_compilation, false,
"simulate GC/compiler thread race related to https://crbug.com/v8/8520")
DEFINE_BOOL(turbo_fast_api_calls, true, "enable fast API calls from TurboFan")
DEFINE_BOOL(fast_api_allow_float_in_sim, false,
"allow float parameters to be passed in simulator mode")
// Float parameters in fast API calls don't work in the simulator in general,
// only for some specially prepared test functions. With this flag implication
// we want to make sure that the fuzzer does not enable float parameters also
// for other tests, which would just lead to errors or crashes.
DEFINE_NEG_IMPLICATION(fuzzing, fast_api_allow_float_in_sim)
#ifdef V8_USE_ZLIB
DEFINE_BOOL(turbo_compress_frame_translations, false,
"compress deoptimization frame translations (experimental)")
#else
DEFINE_BOOL_READONLY(
turbo_compress_frame_translations, false,
"compress deoptimization frame translations (experimental)")
#endif // V8_USE_ZLIB
DEFINE_BOOL(
turbo_inline_js_wasm_calls, true,
"inline JS->Wasm calls (specifically: inline JS-to-Wasm wrappers and then "
"the body of the Wasm function, if applicable)")
DEFINE_BOOL(turbo_optimize_inlined_js_wasm_wrappers, false,
"Run additional optimizations (especially load-elimination) on "
"inlined JS-to-Wasm wrappers")
DEFINE_NEG_NEG_IMPLICATION(turbo_inline_js_wasm_calls,
turbo_optimize_inlined_js_wasm_wrappers)
DEFINE_WEAK_IMPLICATION(future, turbo_optimize_inlined_js_wasm_wrappers)
DEFINE_BOOL(turbo_optimize_apply, true, "optimize Function.prototype.apply")
DEFINE_BOOL(turbo_optimize_math_minmax, true,
"optimize call math.min/max with double array")
DEFINE_BOOL(turbo_collect_feedback_in_generic_lowering, false,
"enable experimental feedback collection in generic lowering.")
DEFINE_BOOL(turboshaft, true, "enable TurboFan's Turboshaft phases for JS")
// Can't use Turbofan without Turboshaft.
DEFINE_NEG_NEG_IMPLICATION(turboshaft, turbofan)
#ifdef V8_ENABLE_EXPERIMENTAL_TSA_BUILTINS
DEFINE_BOOL(turboshaft_enable_debug_features, DEBUG_BOOL,
"enables Turboshaft's DebugPrint, StaticAssert and "
"CheckTurboshaftTypeOf operations")
#else
DEFINE_BOOL(turboshaft_enable_debug_features, false,
"enables Turboshaft's DebugPrint, StaticAssert and "
"CheckTurboshaftTypeOf operations")
#endif
DEFINE_BOOL(turboshaft_wasm_load_elimination, true,
"enable Turboshaft's WasmLoadElimination")
DEFINE_EXPERIMENTAL_FEATURE(
turboshaft_wasm_in_js_inlining,
"inline Wasm code into JS functions via Turboshaft (instead of via "
"TurboFan). Only the Wasm code is inlined in Turboshaft, the JS-to-Wasm "
"wrappers are still inlined in TurboFan. For controlling whether to inline "
"at all, see --turbo-inline-js-wasm-calls.")
// Can't use Turboshaft Wasm-in-JS inlining without the Turboshaft JavaScript
// pipeline. Note however, that this feature is independent of the Turboshaft
// Wasm pipeline (since the inlinee gets compiled with the JS pipeline).
DEFINE_IMPLICATION(turboshaft_wasm_in_js_inlining, turboshaft)
DEFINE_IMPLICATION(turboshaft_wasm_in_js_inlining, turbo_inline_js_wasm_calls)
DEFINE_BOOL(turboshaft_instruction_selection, true,
"run instruction selection on Turboshaft IR directly")
DEFINE_BOOL(turboshaft_load_elimination, true,
"enable Turboshaft's low-level load elimination for JS")
DEFINE_BOOL(turboshaft_loop_peeling, false, "enable Turboshaft's loop peeling")
DEFINE_BOOL(turboshaft_loop_unrolling, true,
"enable Turboshaft's loop unrolling")
DEFINE_BOOL(turboshaft_string_concat_escape_analysis, false,
"enable Turboshaft's escape analysis for string concatenation")
DEFINE_WEAK_IMPLICATION(future, turboshaft_string_concat_escape_analysis)
DEFINE_EXPERIMENTAL_FEATURE(turboshaft_typed_optimizations,
"enable an additional Turboshaft phase that "
"performs optimizations based on type information")
DEFINE_BOOL(turboshaft_wasm_instruction_selection_staged, true,
"run instruction selection on Turboshaft IR directly for wasm, on "
"architectures where we are staging the feature")
DEFINE_EXPERIMENTAL_FEATURE(turbolev, "use Maglev as a frontend for Turboshaft")
// inline_api_calls are not supported by the Turboshaft->Maglev translation.
DEFINE_NEG_IMPLICATION(turbolev, maglev_inline_api_calls)
DEFINE_BOOL(turboshaft_csa, true, "run the CSA pipeline with turboshaft")
DEFINE_IMPLICATION(turboshaft_csa, turboshaft_load_elimination)
#if V8_ENABLE_WEBASSEMBLY
DEFINE_NEG_IMPLICATION(experimental_wasm_shared, liftoff)
#endif
#ifdef DEBUG
DEFINE_UINT64(turboshaft_opt_bisect_limit, std::numeric_limits<uint64_t>::max(),
"stop applying optional optimizations after a specified number "
"of steps, useful for bisecting optimization bugs")
DEFINE_UINT64(turboshaft_opt_bisect_break, std::numeric_limits<uint64_t>::max(),
"abort after a specified number of steps, useful for bisecting "
"optimization bugs")
DEFINE_BOOL(turboshaft_verify_reductions, false,
"check that turboshaft reductions are correct with respect to "
"inferred types")
DEFINE_BOOL(turboshaft_trace_typing, false,
"print typing steps of turboshaft type inference")
DEFINE_BOOL(turboshaft_trace_reduction, false,
"trace individual Turboshaft reduction steps")
DEFINE_BOOL(turboshaft_trace_intermediate_reductions, false,
"trace intermediate Turboshaft reduction steps")
DEFINE_BOOL(turboshaft_trace_emitted, false,
"trace emitted Turboshaft instructions")
DEFINE_WEAK_IMPLICATION(turboshaft_trace_intermediate_reductions,
turboshaft_trace_reduction)
DEFINE_BOOL(turboshaft_trace_unrolling, false,
"trace Turboshaft's loop unrolling reducer")
DEFINE_BOOL(turboshaft_trace_peeling, false,
"trace Turboshaft's loop peeling reducer")
DEFINE_BOOL(turboshaft_trace_load_elimination, false,
"trace Turboshaft's late load elimination")
#else
DEFINE_BOOL_READONLY(turboshaft_trace_reduction, false,
"trace individual Turboshaft reduction steps")
DEFINE_BOOL_READONLY(turboshaft_trace_emitted, false,
"trace emitted Turboshaft instructions")
DEFINE_BOOL_READONLY(turboshaft_trace_intermediate_reductions, false,
"trace intermediate Turboshaft reduction steps")
#endif // DEBUG
DEFINE_BOOL(profile_guided_optimization, true, "profile guided optimization")
DEFINE_BOOL(profile_guided_optimization_for_empty_feedback_vector, true,
"profile guided optimization for empty feedback vector")
DEFINE_INT(invocation_count_for_early_optimization, 30,
"invocation count threshold for early optimization")
DEFINE_INT(invocation_count_for_maglev_with_delay, 600,
"invocation count for maglev for functions which according to "
"profile_guided_optimization are likely to deoptimize before "
"reaching this invocation count")
// Favor memory over execution speed.
DEFINE_BOOL(optimize_for_size, false,
"Enables optimizations which favor memory size over execution "
"speed")
DEFINE_VALUE_IMPLICATION(optimize_for_size, max_semi_space_size, size_t{1})
DEFINE_BOOL(reopt_after_lazy_deopts, true,
"Immediately re-optimize code after some lazy deopts")
// Flags for WebAssembly.
#if V8_ENABLE_WEBASSEMBLY
DEFINE_BOOL(wasm_generic_wrapper, true,
"allow use of the generic js-to-wasm wrapper instead of "
"per-signature wrappers")
DEFINE_INT(wasm_num_compilation_tasks, 128,
"maximum number of parallel compilation tasks for wasm")
DEFINE_VALUE_IMPLICATION(single_threaded, wasm_num_compilation_tasks, 0)
DEFINE_DEBUG_BOOL(trace_wasm_native_heap, false,
"trace wasm native heap events")
DEFINE_BOOL(trace_wasm_offheap_memory, false,
"print details of wasm off-heap memory when the memory measurement "
"API is used")
DEFINE_BOOL(
print_wasm_offheap_memory_size, false,
"print off-heap memory consumption per module and engine when they die")
DEFINE_DEBUG_BOOL(trace_wasm_serialization, false,
"trace serialization/deserialization")
DEFINE_BOOL(wasm_async_compilation, true,
"enable actual asynchronous compilation for WebAssembly.compile")
DEFINE_NEG_IMPLICATION(single_threaded, wasm_async_compilation)
DEFINE_BOOL(wasm_test_streaming, false,
"use streaming compilation instead of async compilation for tests")
DEFINE_BOOL(wasm_native_module_cache, true, "enable the native module cache")
// The actual value used at runtime is clamped to kV8MaxWasmMemory{32,64}Pages.
DEFINE_UINT(wasm_max_mem_pages, kMaxUInt32,
"maximum number of 64KiB memory pages per wasm memory")
DEFINE_UINT(wasm_max_table_size, wasm::kV8MaxWasmTableSize,
"maximum table size of a wasm instance")
DEFINE_UINT(wasm_max_committed_code_mb, kMaxCommittedWasmCodeMB,
"maximum committed code space for wasm (in MB)")
DEFINE_UINT(wasm_max_code_space_size_mb, kDefaultMaxWasmCodeSpaceSizeMb,
"maximum size of a single wasm code space")
DEFINE_BOOL(wasm_tier_up, true,
"enable tier up to the optimizing compiler (requires --liftoff to "
"have an effect)")
DEFINE_BOOL(wasm_dynamic_tiering, true,
"enable dynamic tier up to the optimizing compiler")
DEFINE_NEG_NEG_IMPLICATION(liftoff, wasm_dynamic_tiering)
DEFINE_BOOL(wasm_sync_tier_up, false,
"run tier up jobs synchronously for testing")
DEFINE_INT(wasm_tiering_budget, 13'000'000,
"budget for dynamic tiering (rough approximation of bytes executed")
DEFINE_INT(wasm_wrapper_tiering_budget, wasm::kGenericWrapperBudget,
"budget for wrapper tierup (number of calls until tier-up)")
DEFINE_INT(max_wasm_functions, wasm::kV8MaxWasmDefinedFunctions,
"maximum number of wasm functions defined in a module")
DEFINE_INT(
wasm_caching_threshold, 1'000,
"the amount of wasm top tier code that triggers the next caching event")
// Note: wasm_caching_hard_threshold should always be larger than
// wasm_caching_threshold. If wasm_caching_timeout_ms is 0, the hard threshold
// will be ignored.
DEFINE_INT(wasm_caching_hard_threshold, 1'000'000,
"the amount of wasm top tier code that triggers caching "
"immediately, ignoring the --wasm-caching-timeout-ms")
DEFINE_INT(
wasm_caching_timeout_ms, 2000,
"only trigger caching if no new code was compiled within this timeout (0 "
"to disable this logic and only use --wasm-caching-threshold)")
DEFINE_BOOL(trace_wasm_compilation_times, false,
"print how long it took to compile each wasm function")
DEFINE_INT(wasm_tier_up_filter, -1, "only tier-up function with this index")
DEFINE_INT(wasm_eager_tier_up_function, -1,
"eagerly tier-up function with this index")
DEFINE_DEBUG_BOOL(trace_wasm_decoder, false, "trace decoding of wasm code")
DEFINE_DEBUG_BOOL(trace_wasm_compiler, false, "trace compiling of wasm code")
DEFINE_DEBUG_BOOL(trace_wasm_streaming, false,
"trace streaming compilation of wasm code")
DEFINE_DEBUG_BOOL(trace_wasm_stack_switching, false,
"trace wasm stack switching")
DEFINE_BOOL(stress_wasm_stack_switching, false,
"Always run wasm on a secondary stack, even when it is called "
"with a regular (non-JSPI) export")
DEFINE_INT(wasm_stack_switching_stack_size, V8_DEFAULT_STACK_SIZE_KB,
"default size of stacks for wasm stack-switching (in kB)")
DEFINE_BOOL(liftoff, true,
"enable Liftoff, the baseline compiler for WebAssembly")
DEFINE_BOOL(liftoff_only, false,
"disallow TurboFan compilation for WebAssembly (for testing)")
DEFINE_IMPLICATION(liftoff_only, liftoff)
DEFINE_NEG_IMPLICATION(liftoff_only, wasm_tier_up)
DEFINE_NEG_IMPLICATION(liftoff_only, wasm_dynamic_tiering)
DEFINE_NEG_IMPLICATION(fuzzing, liftoff_only)
DEFINE_DEBUG_BOOL(
enable_testing_opcode_in_wasm, false,
"enables a testing opcode in wasm that is only implemented in TurboFan")
// We can't tier up (from Liftoff to TurboFan) in single-threaded mode, hence
// disable tier up in that configuration for now.
DEFINE_NEG_IMPLICATION(single_threaded, wasm_tier_up)
DEFINE_DEBUG_BOOL(trace_liftoff, false,
"trace Liftoff, the baseline compiler for WebAssembly")
DEFINE_BOOL(trace_wasm_memory, false,
"print all memory updates performed in wasm code")
// Fuzzers use {wasm_tier_mask_for_testing} and {wasm_debug_mask_for_testing}
// together with {liftoff} and {no_wasm_tier_up} to force some functions to be
// compiled with TurboFan or for debug.
DEFINE_INT(wasm_tier_mask_for_testing, 0,
"bitmask of declared(!) function indices to compile with TurboFan "
"instead of Liftoff")
DEFINE_INT(wasm_debug_mask_for_testing, 0,
"bitmask of declared(!) function indices to compile for debugging, "
"only applies if the tier is Liftoff")
// TODO(clemensb): Introduce experimental_wasm_pgo to read from a custom section
// instead of from a local file.
DEFINE_BOOL(
experimental_wasm_pgo_to_file, false,
"experimental: dump Wasm PGO information to a local file (for testing)")
DEFINE_NEG_IMPLICATION(experimental_wasm_pgo_to_file, single_threaded)
DEFINE_BOOL(
experimental_wasm_pgo_from_file, false,
"experimental: read and use Wasm PGO data from a local file (for testing)")
DEFINE_BOOL(validate_asm, true,
"validate asm.js modules and translate them to Wasm")
// Directly interpret asm.js code as regular JavaScript code.
// asm.js validation is disabled since it triggers wasm code generation.
DEFINE_NEG_IMPLICATION(jitless, validate_asm)
#if V8_ENABLE_DRUMBRAKE
// Wasm is put into interpreter-only mode. We repeat flag implications down
// here to ensure they're applied correctly by setting the --jitless flag.
DEFINE_NEG_IMPLICATION(jitless, asm_wasm_lazy_compilation)
DEFINE_NEG_IMPLICATION(jitless, wasm_lazy_compilation)
#endif // V8_ENABLE_DRUMBRAKE
DEFINE_BOOL(suppress_asm_messages, false,
"don't emit asm.js related messages (for golden file testing)")
DEFINE_BOOL(trace_asm_time, false, "print asm.js timing info to the console")
DEFINE_BOOL(trace_asm_scanner, false,
"print tokens encountered by asm.js scanner")
DEFINE_BOOL(trace_asm_parser, false, "verbose logging of asm.js parse failures")
DEFINE_BOOL(stress_validate_asm, false, "try to validate everything as asm.js")
DEFINE_DEBUG_BOOL(dump_wasm_module, false, "dump wasm module bytes")
DEFINE_STRING(dump_wasm_module_path, nullptr,
"directory to dump wasm modules to")
DEFINE_EXPERIMENTAL_FEATURE(
wasm_fast_api,
"Enable direct calls from wasm to fast API functions with bound "
"call function to pass the the receiver as first parameter")
DEFINE_BOOL(wasm_deopt, false, "enable deopts in optimized wasm functions")
DEFINE_WEAK_IMPLICATION(future, wasm_deopt)
// Deopt only works in combination with feedback.
DEFINE_NEG_NEG_IMPLICATION(liftoff, wasm_deopt)
// Declare command-line flags for Wasm features. Warning: avoid using these
// flags directly in the implementation. Instead accept
// wasm::WasmEnabledFeatures for configurability.
#include "src/wasm/wasm-feature-flags.h"
#define DECL_WASM_FLAG(feat, desc, val) \
DEFINE_BOOL(experimental_wasm_##feat, val, "enable " desc " for Wasm")
#define DECL_EXPERIMENTAL_WASM_FLAG(feat, desc, val) \
DEFINE_EXPERIMENTAL_FEATURE(experimental_wasm_##feat, \
"enable " desc " for Wasm")
// Experimental wasm features imply --experimental and get the " (experimental)"
// suffix.
FOREACH_WASM_EXPERIMENTAL_FEATURE_FLAG(DECL_EXPERIMENTAL_WASM_FLAG)
// Staging and shipped features do not imply --experimental.
FOREACH_WASM_STAGING_FEATURE_FLAG(DECL_WASM_FLAG)
FOREACH_WASM_SHIPPED_FEATURE_FLAG(DECL_WASM_FLAG)
#undef DECL_WASM_FLAG
#undef DECL_EXPERIMENTAL_WASM_FLAG
DEFINE_IMPLICATION(experimental_wasm_stack_switching, experimental_wasm_jspi)
DEFINE_IMPLICATION(experimental_wasm_growable_stacks, experimental_wasm_jspi)
DEFINE_IMPLICATION(experimental_wasm_imported_strings_utf8,
experimental_wasm_imported_strings)
DEFINE_BOOL(wasm_staging, false, "enable staged wasm features")
#define WASM_STAGING_IMPLICATION(feat, desc, val) \
DEFINE_IMPLICATION(wasm_staging, experimental_wasm_##feat)
FOREACH_WASM_STAGING_FEATURE_FLAG(WASM_STAGING_IMPLICATION)
#undef WASM_STAGING_IMPLICATION
DEFINE_BOOL(wasm_opt, true, "enable wasm optimization")
DEFINE_BOOL(wasm_bounds_checks, true,
"enable bounds checks (disable for performance testing only)")
DEFINE_BOOL(wasm_stack_checks, true,
"enable stack checks (disable for performance testing only)")
DEFINE_BOOL(
wasm_enforce_bounds_checks, false,
"enforce explicit bounds check even if the trap handler is available")
// "no bounds checks" implies "no enforced bounds checks".
DEFINE_NEG_NEG_IMPLICATION(wasm_bounds_checks, wasm_enforce_bounds_checks)
DEFINE_BOOL(wasm_math_intrinsics, true,
"intrinsify some Math imports into wasm")
DEFINE_BOOL(wasm_inlining_call_indirect, false,
"enable speculative inlining of Wasm indirect calls")
DEFINE_WEAK_IMPLICATION(future, wasm_inlining_call_indirect)
// This doesn't make sense without and requires the basic inlining machinery,
// e.g., for allocating feedback vectors, so we automatically enable it.
DEFINE_IMPLICATION(wasm_inlining_call_indirect, wasm_inlining)
DEFINE_BOOL(wasm_inlining, true,
"enable inlining of Wasm functions into Wasm functions")
DEFINE_SIZE_T(wasm_inlining_budget, 5000,
"maximum graph size (in TF nodes) that allows inlining more")
DEFINE_SIZE_T(wasm_inlining_max_size, 500,
"maximum function size (in wire bytes) that may be inlined")
DEFINE_SIZE_T(
wasm_inlining_factor, 3,
"maximum multiple graph size (in TF nodes) in comparison to initial size")
DEFINE_SIZE_T(wasm_inlining_min_budget, 50,
"minimum graph size budget (in TF nodes) for which the "
"wasm_inlinining_factor does not apply")
DEFINE_BOOL(wasm_inlining_ignore_call_counts, false,
"Ignore call counts when considering inlining candidates. The flag "
"is supposed to be used for fuzzing")
DEFINE_BOOL(trace_wasm_inlining, false, "trace wasm inlining")
DEFINE_BOOL(trace_wasm_typer, false, "trace wasm typer")
DEFINE_BOOL(wasm_loop_unrolling, true,
"enable loop unrolling for wasm functions")
DEFINE_BOOL(wasm_loop_peeling, true, "enable loop peeling for wasm functions")
DEFINE_SIZE_T(wasm_loop_peeling_max_size, 1000, "maximum size for peeling")
DEFINE_BOOL(trace_wasm_loop_peeling, false, "trace wasm loop peeling")
DEFINE_BOOL(wasm_fuzzer_gen_test, false,
"generate a test case when running a wasm fuzzer")
DEFINE_IMPLICATION(wasm_fuzzer_gen_test, single_threaded)
DEFINE_BOOL(print_wasm_code, false, "print WebAssembly code")
DEFINE_INT(print_wasm_code_function_index, -1,
"print WebAssembly code for function at index")
DEFINE_BOOL(print_wasm_stub_code, false, "print WebAssembly stub code")
DEFINE_BOOL(asm_wasm_lazy_compilation, true,
"enable lazy compilation for asm.js translated to wasm (see "
"--validate-asm)")
DEFINE_BOOL(wasm_lazy_compilation, true,
"enable lazy compilation for all wasm modules")
DEFINE_DEBUG_BOOL(trace_wasm_lazy_compilation, false,
"trace lazy compilation of wasm functions")
DEFINE_EXPERIMENTAL_FEATURE(
wasm_lazy_validation,
"enable lazy validation for lazily compiled wasm functions")
DEFINE_WEAK_IMPLICATION(wasm_lazy_validation, wasm_lazy_compilation)
DEFINE_BOOL(wasm_simd_ssse3_codegen, false, "allow wasm SIMD SSSE3 codegen")
DEFINE_BOOL(wasm_code_gc, true, "enable garbage collection of wasm code")
DEFINE_BOOL(trace_wasm_code_gc, false, "trace garbage collection of wasm code")
DEFINE_BOOL(stress_wasm_code_gc, false,
"stress test garbage collection of wasm code")
DEFINE_INT(wasm_max_initial_code_space_reservation, 0,
"maximum size of the initial wasm code space reservation (in MB)")
DEFINE_BOOL(stress_wasm_memory_moving, false,
"always move non-shared bounds-checked Wasm memory on grow")
DEFINE_SIZE_T(wasm_max_module_size, wasm::kV8MaxWasmModuleSize,
"maximum allowed size of wasm modules")
DEFINE_SIZE_T(wasm_disassembly_max_mb, 1000,
"maximum size of produced disassembly (in MB, approximate)")
DEFINE_INT(wasm_capi_thread_pool_size, 0,
"size of the thread pool used by the wasm C API, with 0 meaning the "
"maximum number of threads")
DEFINE_BOOL(trace_wasm, false, "trace wasm function calls")
// Inlining breaks --trace-wasm, hence disable that if --trace-wasm is enabled.
// TODO(40898108,mliedtke,manoskouk): We should fix this; now that inlining is
// enabled by default, one cannot trace the production configuration anymore.
DEFINE_NEG_IMPLICATION(trace_wasm, wasm_inlining)
// Flags for Wasm GDB remote debugging.
#ifdef V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING
#define DEFAULT_WASM_GDB_REMOTE_PORT 8765
DEFINE_BOOL(wasm_gdb_remote, false,
"enable GDB-remote for WebAssembly debugging")
DEFINE_NEG_IMPLICATION(wasm_gdb_remote, wasm_tier_up)
DEFINE_INT(wasm_gdb_remote_port, DEFAULT_WASM_GDB_REMOTE_PORT,
"default port for WebAssembly debugging with LLDB.")
DEFINE_BOOL(wasm_pause_waiting_for_debugger, false,
"pause at the first Webassembly instruction waiting for a debugger "
"to attach")
DEFINE_BOOL(trace_wasm_gdb_remote, false, "trace Webassembly GDB-remote server")
#endif // V8_ENABLE_WASM_GDB_REMOTE_DEBUGGING
// wasm instance management
DEFINE_DEBUG_BOOL(trace_wasm_instances, false,
"trace creation and collection of wasm instances")
// Flags for WASM SIMD256 revectorize
#ifdef V8_ENABLE_WASM_SIMD256_REVEC
DEFINE_EXPERIMENTAL_FEATURE(
experimental_wasm_revectorize,
"enable 128 to 256 bit revectorization for Webassembly SIMD")
DEFINE_BOOL(trace_wasm_revectorize, false, "trace wasm revectorize")
#endif // V8_ENABLE_WASM_SIMD256_REVEC
#if V8_TARGET_ARCH_ARM64 || V8_TARGET_ARCH_X64
// TODO(388290793): Fix trap handling for memory64, or remove it altogether.
DEFINE_BOOL(wasm_memory64_trap_handling, false,
"Use trap handling for Wasm memory64 bounds checks")
#else
DEFINE_BOOL_READONLY(wasm_memory64_trap_handling, false,
"Use trap handling for Wasm memory64 bounds checks (not "
"supported for this architecture)")
#endif // V8_TARGET_ARCH_ARM64 || V8_TARGET_ARCH_X64
#ifdef V8_ENABLE_DRUMBRAKE
// DrumBrake flags.
DEFINE_EXPERIMENTAL_FEATURE(wasm_jitless,
"Execute all wasm code in the Wasm interpreter")
DEFINE_BOOL(wasm_jitless_if_available_for_testing, false,
"Enables the Wasm interpreter, for testing, but only if "
"the 'v8_enable_drumbrake' flag is set.")
DEFINE_IMPLICATION(wasm_jitless_if_available_for_testing, wasm_jitless)
DEFINE_BOOL(drumbrake_compact_bytecode, false,
"Compress the Wasm interpreter bytecode")
DEFINE_BOOL(trace_drumbrake_compact_bytecode, false,
"Traces the Wasm interpreter compact bytecode")
DEFINE_BOOL(drumbrake_fuzzer_timeout, false,
"enable timeout for wasm fuzzer (for testing)")
DEFINE_SIZE_T(drumbrake_fuzzer_timeout_limit_ms, 10000,
"timeout for wasm fuzzer (in ms)")
#ifdef V8_ENABLE_DRUMBRAKE_TRACING
DEFINE_BOOL(trace_drumbrake_bytecode_generator, false,
"trace drumbrake generation of interpreter bytecode")
DEFINE_BOOL(trace_drumbrake_execution, false,
"trace drumbrake execution of wasm code")
DEFINE_BOOL(trace_drumbrake_execution_verbose, false,
"print more information for the drumbrake execution of wasm code")
DEFINE_IMPLICATION(trace_drumbrake_execution_verbose, trace_drumbrake_execution)
DEFINE_BOOL(redirect_drumbrake_traces, false,
"write drumbrake traces into file <pid>-<isolate id>.dbt")
DEFINE_STRING(
trace_drumbrake_filter, "*",
"filter for selecting which wasm functions to trace in the interpreter")
#endif // V8_ENABLE_DRUMBRAKE_TRACING
DEFINE_BOOL(drumbrake_super_instructions, true,
"enable drumbrake merged wasm instructions optimization")
DEFINE_BOOL(drumbrake_register_optimization, true,
"enable passing the top stack value in a register in drumbrake")
// Directly interpret asm.js code as regular JavaScript code, instead of
// translating it to Wasm bytecode first and then interpreting that with
// DrumBrake. (validate_asm=false turns off asm.js to Wasm compilation.)
DEFINE_NEG_IMPLICATION(wasm_jitless, validate_asm)
// --wasm-jitless resets {asm-,}wasm-lazy-compilation.
DEFINE_NEG_IMPLICATION(wasm_jitless, asm_wasm_lazy_compilation)
DEFINE_NEG_IMPLICATION(wasm_jitless, wasm_lazy_compilation)
DEFINE_NEG_IMPLICATION(wasm_jitless, wasm_lazy_validation)
DEFINE_NEG_IMPLICATION(wasm_jitless, wasm_tier_up)
// --wasm-enable-exec-time-histograms works both in jitted and jitless mode
// and enables histogram V8.Jit[less]WasmExecutionPercentage, which measures
// the percentage of time spent running Wasm code. Note that generating samples
// for this metric causes a small performance degradation, and requires setting
// the additional flag --slow-histograms.
DEFINE_BOOL(wasm_enable_exec_time_histograms, false,
"enables histograms that track the time spent executing Wasm code")
DEFINE_INT(wasm_exec_time_histogram_sample_duration, 1000,
"sample duration for V8.Jit[less]WasmExecutionPercentage, in msec")
DEFINE_INT(wasm_exec_time_histogram_sample_period, 4000,
"sample period for V8.Jit[less]WasmExecutionPercentage, in msec")
DEFINE_INT(wasm_exec_time_histogram_slow_threshold, 10000,
"V8.Jit[less]WasmExecutionPercentage threshold used to detect "
"Wasm-intensive workloads (0-100000)")
DEFINE_INT(wasm_exec_time_slow_threshold_samples_count, 1,
"number of V8.Jit[less]WasmExecutionPercentage samples used to "
"calculate the threshold for the V8.Jit[less]WasmExecutionTooSlow "
"histogram")
DEFINE_IMPLICATION(wasm_enable_exec_time_histograms, slow_histograms)
DEFINE_NEG_IMPLICATION(wasm_enable_exec_time_histograms,
turbo_inline_js_wasm_calls)
DEFINE_NEG_IMPLICATION(wasm_enable_exec_time_histograms, wasm_generic_wrapper)
#else // V8_ENABLE_DRUMBRAKE
DEFINE_BOOL_READONLY(wasm_jitless, false,
"execute all Wasm code in the Wasm interpreter")
DEFINE_BOOL(wasm_jitless_if_available_for_testing, false, "")
#endif // V8_ENABLE_DRUMBRAKE
#endif // V8_ENABLE_WEBASSEMBLY
DEFINE_INT(stress_sampling_allocation_profiler, 0,
"Enables sampling allocation profiler with X as a sample interval")
// Garbage collections flags.
DEFINE_BOOL(lazy_new_space_shrinking, false,
"Enables the lazy new space shrinking strategy")
DEFINE_SIZE_T(min_semi_space_size, 0,
"min size of a semi-space (in MBytes), the new space consists of "
"two semi-spaces")
DEFINE_SIZE_T(max_semi_space_size, 0,
"max size of a semi-space (in MBytes), the new space consists of "
"two semi-spaces")
DEFINE_INT(semi_space_growth_factor, 2, "factor by which to grow the new space")
// Set minimum semi space growth factor
DEFINE_MIN_VALUE_IMPLICATION(semi_space_growth_factor, 2)
DEFINE_SIZE_T(max_old_space_size, 0, "max size of the old space (in Mbytes)")
DEFINE_SIZE_T(
max_heap_size, 0,
"max size of the heap (in Mbytes) "
"both max_semi_space_size and max_old_space_size take precedence. "
"All three flags cannot be specified at the same time.")
DEFINE_SIZE_T(initial_heap_size, 0, "initial size of the heap (in Mbytes)")
DEFINE_SIZE_T(initial_old_space_size, 0, "initial old space size (in Mbytes)")
DEFINE_BOOL(separate_gc_phases, false,
"young and full garbage collection phases are not overlapping")
DEFINE_BOOL(gc_global, false, "always perform global GCs")
// TODO(12950): The next three flags only have an effect if
// V8_ENABLE_ALLOCATION_TIMEOUT is set, so we should only define them in that
// config. That currently breaks Node's parallel/test-domain-error-types test
// though.
DEFINE_INT(random_gc_interval, 0,
"Collect garbage after random(0, X) V8 allocations. It overrides "
"gc_interval.")
DEFINE_INT(gc_interval, -1, "garbage collect after <n> allocations")
DEFINE_INT(cppgc_random_gc_interval, 0,
"Collect garbage after random(0, X) cppgc allocations.")
DEFINE_INT(retain_maps_for_n_gc, 2,
"keeps maps alive for <n> old space garbage collections")
DEFINE_BOOL(trace_gc, false,
"print one trace line following each garbage collection")
DEFINE_BOOL(trace_gc_nvp, false,
"print one detailed trace line in name=value format "
"after each garbage collection")
DEFINE_BOOL(trace_gc_ignore_scavenger, false,
"do not print trace line after scavenger collection")
DEFINE_BOOL(trace_memory_reducer, false, "print memory reducer behavior")
DEFINE_BOOL(trace_gc_verbose, false,
"print more details following each garbage collection")
DEFINE_IMPLICATION(trace_gc_verbose, trace_gc)
DEFINE_BOOL(trace_gc_freelists, false,
"prints details of each freelist before and after "
"each major garbage collection")
DEFINE_BOOL(trace_gc_freelists_verbose, false,
"prints details of freelists of each page before and after "
"each major garbage collection")
DEFINE_IMPLICATION(trace_gc_freelists_verbose, trace_gc_freelists)
DEFINE_BOOL(trace_gc_heap_layout, false,
"print layout of pages in heap before and after gc")
DEFINE_BOOL(trace_gc_heap_layout_ignore_minor_gc, true,
"do not print trace line before and after minor-gc")
DEFINE_BOOL(trace_evacuation_candidates, false,
"Show statistics about the pages evacuation by the compaction")
DEFINE_BOOL(trace_pending_allocations, false,
"trace calls to Heap::IsAllocationPending that return true")
DEFINE_INT(trace_allocation_stack_interval, -1,
"print stack trace after <n> free-list allocations")
DEFINE_INT(trace_duplicate_threshold_kb, 0,
"print duplicate objects in the heap if their size is more than "
"given threshold")
DEFINE_BOOL(trace_fragmentation, false, "report fragmentation for old space")
DEFINE_BOOL(trace_fragmentation_verbose, false,
"report fragmentation for old space (detailed)")
DEFINE_BOOL(minor_ms_trace_fragmentation, false,
"trace fragmentation after marking")
DEFINE_BOOL(trace_evacuation, false, "report evacuation statistics")
DEFINE_BOOL(trace_mutator_utilization, false,
"print mutator utilization, allocation speed, gc speed")
DEFINE_BOOL(incremental_marking, true, "use incremental marking")
DEFINE_BOOL(incremental_marking_bailout_when_ahead_of_schedule, true,
"bails out of incremental marking when ahead of schedule")
DEFINE_BOOL(incremental_marking_task, true, "use tasks for incremental marking")
DEFINE_BOOL(incremental_marking_start_user_visible, false,
"Starts incremental marking with kUserVisible priority.")
DEFINE_INT(incremental_marking_soft_trigger, 0,
"threshold for starting incremental marking via a task in percent "
"of available space: limit - size")
DEFINE_INT(incremental_marking_hard_trigger, 0,
"threshold for starting incremental marking immediately in percent "
"of available space: limit - size")
DEFINE_BOOL(trace_unmapper, false, "Trace the unmapping")
DEFINE_BOOL(parallel_scavenge, true, "parallel scavenge")
DEFINE_BOOL(minor_gc_task, true, "schedule minor GC tasks")
DEFINE_UINT(minor_gc_task_trigger, 80,
"minor GC task trigger in percent of the current heap limit")
DEFINE_BOOL(minor_gc_task_with_lower_priority, false,
"schedules the minor GC task with kUserVisible priority.")
DEFINE_BOOL(trace_parallel_scavenge, false, "trace parallel scavenge")
DEFINE_EXPERIMENTAL_FEATURE(
cppgc_young_generation,
"run young generation garbage collections in Oilpan")
// CppGC young generation (enables unified young heap) is based on Minor MS.
DEFINE_IMPLICATION(cppgc_young_generation, minor_ms)
// Unified young generation disables the unmodified wrapper reclamation
// optimization.
DEFINE_NEG_IMPLICATION(cppgc_young_generation, reclaim_unmodified_wrappers)
DEFINE_BOOL(optimize_gc_for_battery, false, "optimize GC for battery")
#if defined(V8_ATOMIC_OBJECT_FIELD_WRITES)
DEFINE_BOOL(concurrent_marking, true, "use concurrent marking")
#else
// Concurrent marking cannot be used without atomic object field loads and
// stores.
DEFINE_BOOL(concurrent_marking, false, "use concurrent marking")
#endif
DEFINE_INT(
concurrent_marking_max_worker_num, 7,
"max worker number of concurrent marking, 0 for NumberOfWorkerThreads")
DEFINE_BOOL(concurrent_array_buffer_sweeping, true,
"concurrently sweep array buffers")
DEFINE_BOOL(stress_concurrent_allocation, false,
"start background threads that allocate memory")
DEFINE_BOOL(parallel_marking, true, "use parallel marking in atomic pause")
DEFINE_INT(ephemeron_fixpoint_iterations, 10,
"number of fixpoint iterations it takes to switch to linear "
"ephemeron algorithm")
DEFINE_BOOL(trace_concurrent_marking, false, "trace concurrent marking")
DEFINE_BOOL(concurrent_sweeping, true, "use concurrent sweeping")
DEFINE_NEG_NEG_IMPLICATION(concurrent_sweeping,
concurrent_array_buffer_sweeping)
DEFINE_BOOL(parallel_compaction, true, "use parallel compaction")
DEFINE_BOOL(parallel_pointer_update, true,
"use parallel pointer update during compaction")
DEFINE_BOOL(parallel_weak_ref_clearing, true,
"use parallel threads to clear weak refs in the atomic pause.")
DEFINE_BOOL(detect_ineffective_gcs_near_heap_limit, true,
"trigger out-of-memory failure to avoid GC storm near heap limit")
DEFINE_BOOL(trace_incremental_marking, false,
"trace progress of the incremental marking")
DEFINE_BOOL(trace_stress_marking, false, "trace stress marking progress")
DEFINE_BOOL(trace_stress_scavenge, false, "trace stress scavenge progress")
DEFINE_BOOL(track_gc_object_stats, false,
"track object counts and memory usage")
DEFINE_BOOL(trace_gc_object_stats, false,
"trace object counts and memory usage")
DEFINE_BOOL(trace_zone_stats, false, "trace zone memory usage")
DEFINE_GENERIC_IMPLICATION(
trace_zone_stats,
TracingFlags::zone_stats.store(
v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE))
DEFINE_SIZE_T(
zone_stats_tolerance, 1 * MB,
"report a tick only when allocated zone memory changes by this amount")
DEFINE_BOOL(trace_zone_type_stats, false, "trace per-type zone memory usage")
DEFINE_GENERIC_IMPLICATION(
trace_zone_type_stats,
TracingFlags::zone_stats.store(
v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE))
DEFINE_DEBUG_BOOL(trace_backing_store, false, "trace backing store events")
DEFINE_INT(gc_stats, 0, "Used by tracing internally to enable gc statistics")
DEFINE_IMPLICATION(trace_gc_object_stats, track_gc_object_stats)
DEFINE_GENERIC_IMPLICATION(
track_gc_object_stats,
TracingFlags::gc_stats.store(
v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE))
DEFINE_GENERIC_IMPLICATION(
trace_gc_object_stats,
TracingFlags::gc_stats.store(
v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE))
DEFINE_NEG_IMPLICATION(trace_gc_object_stats, incremental_marking)
DEFINE_NEG_NEG_IMPLICATION(incremental_marking, concurrent_marking)
DEFINE_NEG_NEG_IMPLICATION(parallel_marking, concurrent_marking)
DEFINE_IMPLICATION(concurrent_marking, incremental_marking)
DEFINE_BOOL(track_detached_contexts, true,
"track native contexts that are expected to be garbage collected")
DEFINE_BOOL(trace_detached_contexts, false,
"trace native contexts that are expected to be garbage collected")
DEFINE_IMPLICATION(trace_detached_contexts, track_detached_contexts)
#ifdef VERIFY_HEAP
DEFINE_BOOL(verify_heap, false, "verify heap pointers before and after GC")
DEFINE_BOOL(verify_heap_skip_remembered_set, false,
"disable remembered set verification")
#else
DEFINE_BOOL_READONLY(verify_heap, false,
"verify heap pointers before and after GC")
#endif
#if V8_OS_DARWIN
DEFINE_BOOL(safepoint_bump_qos_class, false,
"Bump QOS class for running threads to reach safepoint")
#endif
DEFINE_BOOL(move_object_start, true, "enable moving of object starts")
DEFINE_BOOL(memory_reducer, true, "use memory reducer")
DEFINE_BOOL(memory_reducer_favors_memory, true,
"memory reducer runs GC with ReduceMemoryFootprint flag")
DEFINE_BOOL(memory_reducer_for_small_heaps, true,
"use memory reducer for small heaps")
DEFINE_INT(memory_reducer_gc_count, 2,
"Maximum number of memory reducer GCs scheduled")
DEFINE_BOOL(
external_memory_accounted_in_global_limit, false,
"External memory limits are computed as part of global limits in v8 Heap.")
DEFINE_BOOL(gc_speed_uses_counters, false,
"Old gen GC speed is computed directly from gc tracer counters.")
DEFINE_INT(heap_growing_percent, 0,
"specifies heap growing factor as (1 + heap_growing_percent/100)")
DEFINE_INT(v8_os_page_size, 0, "override OS page size (in KBytes)")
DEFINE_BOOL(allocation_buffer_parking, true, "allocation buffer parking")
DEFINE_BOOL(compact, true,
"Perform compaction on full GCs based on V8's default heuristics")
DEFINE_BOOL(compact_code_space, true,
"Perform code space compaction on full collections.")
DEFINE_BOOL(compact_on_every_full_gc, false,
"Perform compaction on every full GC")
DEFINE_BOOL(compact_with_stack, true,
"Perform compaction when finalizing a full GC with stack")
DEFINE_BOOL(
compact_code_space_with_stack, true,
"Perform code space compaction when finalizing a full GC with stack")
// Disabling compaction with stack implies also disabling code space compaction
// with stack.
DEFINE_NEG_NEG_IMPLICATION(compact_with_stack, compact_code_space_with_stack)
DEFINE_BOOL(shortcut_strings_with_stack, true,
"Shortcut Strings during GC with stack")
DEFINE_BOOL(stress_compaction, false,
"Stress GC compaction to flush out bugs (implies "
"--force_marking_deque_overflows)")
DEFINE_BOOL(stress_compaction_random, false,
"Stress GC compaction by selecting random percent of pages as "
"evacuation candidates. Overrides stress_compaction.")
DEFINE_IMPLICATION(stress_compaction, force_marking_deque_overflows)
DEFINE_IMPLICATION(stress_compaction, gc_global)
DEFINE_VALUE_IMPLICATION(stress_compaction, max_semi_space_size, (size_t)1)
DEFINE_BOOL(flush_baseline_code, false,
"flush of baseline code when it has not been executed recently")
DEFINE_BOOL(flush_bytecode, true,
"flush of bytecode when it has not been executed recently")
DEFINE_INT(bytecode_old_age, 6, "number of gcs before we flush code")
DEFINE_BOOL(flush_code_based_on_time, false,
"Use time-base code flushing instead of age.")
DEFINE_BOOL(flush_code_based_on_tab_visibility, false,
"Flush code when tab goes into the background.")
DEFINE_INT(bytecode_old_time, 30, "number of seconds before we flush code")
DEFINE_BOOL(stress_flush_code, false, "stress code flushing")
DEFINE_BOOL(trace_flush_code, false, "trace bytecode flushing")
DEFINE_BOOL(use_marking_progress_bar, true,
"Use a progress bar to scan large objects in increments when "
"incremental marking is active.")
DEFINE_BOOL(stress_per_context_marking_worklist, false,
"Use per-context worklist for marking")
DEFINE_BOOL(force_marking_deque_overflows, false,
"force overflows of marking deque by reducing it's size "
"to 64 words")
DEFINE_BOOL(stress_incremental_marking, false,
"force incremental marking for small heaps and run it more often")
DEFINE_BOOL(fuzzer_gc_analysis, false,
"prints number of allocations and enables analysis mode for gc "
"fuzz testing, e.g. --stress-marking, --stress-scavenge")
DEFINE_INT(stress_marking, 0,
"force marking at random points between 0 and X (inclusive) percent "
"of the regular marking start limit")
DEFINE_INT(stress_scavenge, 0,
"force scavenge at random points between 0 and X (inclusive) "
"percent of the new space capacity")
DEFINE_VALUE_IMPLICATION(fuzzer_gc_analysis, stress_marking, 99)
DEFINE_VALUE_IMPLICATION(fuzzer_gc_analysis, stress_scavenge, 99)
DEFINE_BOOL(
reclaim_unmodified_wrappers, true,
"reclaim otherwise unreachable unmodified wrapper objects when possible")
// These flags will be removed after experiments. Do not rely on them.
DEFINE_BOOL(gc_experiment_less_compaction, false,
"less compaction in non-memory reducing mode")
DEFINE_INT(gc_memory_reducer_start_delay_ms, 8000,
"Delay before memory reducer start")
DEFINE_BOOL(concurrent_marking_high_priority_threads, false,
"use high priority threads for concurrent Marking")
DEFINE_BOOL(disable_abortjs, false, "disables AbortJS runtime function")
DEFINE_BOOL(randomize_all_allocations, false,
"randomize virtual memory reservations by ignoring any hints "
"passed when allocating pages")
DEFINE_BOOL(manual_evacuation_candidates_selection, false,
"Test mode only flag. It allows an unit test to select evacuation "
"candidates pages (requires --stress_compaction).")
DEFINE_BOOL(clear_free_memory, false, "initialize free memory with 0")
DEFINE_BOOL(idle_gc_on_context_disposal, true, "idle gc on context disposal")
DEFINE_BOOL(trace_context_disposal, false, "trace context disposal")
// v8::CppHeap flags that allow fine-grained control of how C++ memory is
// reclaimed in the garbage collector.
DEFINE_BOOL(cppheap_incremental_marking, false,
"use incremental marking for CppHeap")
DEFINE_NEG_NEG_IMPLICATION(incremental_marking, cppheap_incremental_marking)
DEFINE_NEG_NEG_IMPLICATION(incremental_marking, memory_reducer)
DEFINE_WEAK_IMPLICATION(incremental_marking, cppheap_incremental_marking)
DEFINE_BOOL(cppheap_concurrent_marking, false,
"use concurrent marking for CppHeap")
DEFINE_NEG_NEG_IMPLICATION(cppheap_incremental_marking,
cppheap_concurrent_marking)
DEFINE_NEG_NEG_IMPLICATION(concurrent_marking, cppheap_concurrent_marking)
DEFINE_WEAK_IMPLICATION(concurrent_marking, cppheap_concurrent_marking)
DEFINE_BOOL(memory_balancer, false,
"use membalancer, "
"a new heap limit balancing algorithm")
DEFINE_FLOAT(memory_balancer_c_value, 3e-10,
"c value for membalancer. "
"A special constant to balance between memory and space tradeoff. "
"The smaller the more memory it uses.")
DEFINE_NEG_IMPLICATION(memory_balancer, memory_reducer)
DEFINE_BOOL(trace_memory_balancer, false, "print memory balancer behavior.")
// assembler-ia32.cc / assembler-arm.cc / assembler-arm64.cc / assembler-x64.cc
#ifdef V8_ENABLE_DEBUG_CODE
DEFINE_BOOL(debug_code, DEBUG_BOOL,
"generate extra code (assertions) for debugging")
#if defined(V8_ENABLE_SLOW_DEBUG_CODE_BY_DEFAULT) || \
defined(ENABLE_SLOW_DCHECKS)
#define V8_ENABLE_SLOW_DEBUG_CODE_BY_DEFAULT_BOOL true
#else
#define V8_ENABLE_SLOW_DEBUG_CODE_BY_DEFAULT_BOOL false
#endif
// slow_debug_code is enabled by default for builds with is_debug or
// v8_enable_slow_dchecks.
DEFINE_BOOL(slow_debug_code, V8_ENABLE_SLOW_DEBUG_CODE_BY_DEFAULT_BOOL,
"generate slow extra code (assertions) for debugging")
DEFINE_NEG_NEG_IMPLICATION(debug_code, slow_debug_code)
#else
DEFINE_BOOL_READONLY(debug_code, false, "")
DEFINE_BOOL_READONLY(slow_debug_code, false, "")
#endif
#ifdef V8_CODE_COMMENTS
DEFINE_BOOL(code_comments, false,
"emit comments in code disassembly; for more readable source "
"positions you should add --no-concurrent_recompilation")
#else
DEFINE_BOOL_READONLY(code_comments, false, "")
#endif
DEFINE_BOOL(enable_sse3, true, "enable use of SSE3 instructions if available")
DEFINE_BOOL(enable_ssse3, true, "enable use of SSSE3 instructions if available")
DEFINE_BOOL(enable_sse4_1, true,
"enable use of SSE4.1 instructions if available")
DEFINE_BOOL(enable_sse4_2, true,
"enable use of SSE4.2 instructions if available")
DEFINE_BOOL(enable_sahf, true,
"enable use of SAHF instruction if available (X64 only)")
DEFINE_BOOL(enable_avx, true, "enable use of AVX instructions if available")
DEFINE_BOOL(enable_avx2, true, "enable use of AVX2 instructions if available")
DEFINE_BOOL(enable_avx_vnni, true,
"enable use of AVX-VNNI instructions if available")
DEFINE_BOOL(enable_avx_vnni_int8, true,
"enable use of AVX-VNNI-INT8 instructions if available")
DEFINE_BOOL(enable_fma3, true, "enable use of FMA3 instructions if available")
DEFINE_BOOL(enable_f16c, true, "enable use of F16C instructions if available")
DEFINE_BOOL(enable_bmi1, true, "enable use of BMI1 instructions if available")
DEFINE_BOOL(enable_bmi2, true, "enable use of BMI2 instructions if available")
DEFINE_BOOL(enable_lzcnt, true, "enable use of LZCNT instruction if available")
DEFINE_BOOL(enable_popcnt, true,
"enable use of POPCNT instruction if available")
DEFINE_STRING(arm_arch, ARM_ARCH_DEFAULT,
"generate instructions for the selected ARM architecture if "
"available: armv6, armv7, armv7+sudiv or armv8")
DEFINE_BOOL(force_long_branches, false,
"force all emitted branches to be in long mode (MIPS/PPC only)")
DEFINE_STRING(mcpu, "auto", "enable optimization for specific cpu")
DEFINE_BOOL(partial_constant_pool, true,
"enable use of partial constant pools (x64 only)")
DEFINE_STRING(sim_arm64_optional_features, "none",
"enable optional features on the simulator for testing: none or "
"all")
DEFINE_BOOL(intel_jcc_erratum_mitigation, true,
"enable mitigation for Intel JCC erratum on affected CPUs")
#if defined(V8_TARGET_ARCH_RISCV32) || defined(V8_TARGET_ARCH_RISCV64)
DEFINE_BOOL(riscv_trap_to_simulator_debugger, false,
"enable simulator trap to debugger")
DEFINE_BOOL(riscv_debug, false, "enable debug prints")
DEFINE_BOOL(riscv_constant_pool, true, "enable constant pool (RISCV only)")
DEFINE_BOOL(riscv_c_extension, false,
"enable compressed extension isa variant (RISCV only)")
DEFINE_BOOL(riscv_b_extension, false,
"enable B extension isa variant (RISCV only)")
#endif
// Controlling source positions for Torque/CSA code.
DEFINE_BOOL(enable_source_at_csa_bind, false,
"Include source information in the binary at CSA bind locations.")
// Deprecated ARM flags (replaced by arm_arch).
DEFINE_MAYBE_BOOL(enable_armv7, "deprecated (use --arm_arch instead)")
DEFINE_MAYBE_BOOL(enable_vfp3, "deprecated (use --arm_arch instead)")
DEFINE_MAYBE_BOOL(enable_32dregs, "deprecated (use --arm_arch instead)")
DEFINE_MAYBE_BOOL(enable_neon, "deprecated (use --arm_arch instead)")
DEFINE_MAYBE_BOOL(enable_sudiv, "deprecated (use --arm_arch instead)")
DEFINE_MAYBE_BOOL(enable_armv8, "deprecated (use --arm_arch instead)")
// regexp-macro-assembler-*.cc
DEFINE_BOOL(enable_regexp_unaligned_accesses, true,
"enable unaligned accesses for the regexp engine")
// api.cc
DEFINE_BOOL(script_streaming, true, "enable parsing on background")
DEFINE_BOOL(stress_background_compile, false,
"stress test parsing on background")
DEFINE_BOOL(concurrent_cache_deserialization, true,
"enable deserializing code caches on background")
DEFINE_BOOL(
merge_background_deserialized_script_with_compilation_cache, true,
"After deserializing code cache data on a background thread, merge it into "
"an existing Script if one is found in the Isolate compilation cache")
DEFINE_BOOL(verify_code_merge, false, "Verify scope infos after merge")
// Fix https://issues.chromium.org/u/1/issues/366783806 before enabling.
DEFINE_BOOL(
experimental_embedder_instance_types, false,
"enable type checks based on instance types provided by the embedder")
DEFINE_IMPLICATION(experimental_embedder_instance_types, experimental)
// bootstrapper.cc
DEFINE_BOOL(expose_gc, false, "expose gc extension")
DEFINE_STRING(expose_gc_as, nullptr,
"expose gc extension under the specified name")
DEFINE_IMPLICATION(expose_gc_as, expose_gc)
DEFINE_BOOL(expose_externalize_string, false,
"expose externalize string extension")
DEFINE_BOOL(expose_statistics, false, "expose statistics extension")
DEFINE_BOOL(expose_trigger_failure, false, "expose trigger-failure extension")
DEFINE_BOOL(expose_ignition_statistics, false,
"expose ignition-statistics extension (requires building with "
"v8_enable_ignition_dispatch_counting)")
DEFINE_INT(stack_trace_limit, 10, "number of stack frames to capture")
DEFINE_BOOL(builtins_in_stack_traces, false,
"show built-in functions in stack traces")
DEFINE_BOOL(experimental_stack_trace_frames, false,
"enable experimental frames (API/Builtins) and stack trace layout")
DEFINE_BOOL(disallow_code_generation_from_strings, false,
"disallow eval and friends")
DEFINE_BOOL(expose_async_hooks, false, "expose async_hooks object")
DEFINE_STRING(expose_cputracemark_as, nullptr,
"expose cputracemark extension under the specified name")
#ifdef ENABLE_VTUNE_TRACEMARK
DEFINE_BOOL(enable_vtune_domain_support, true, "enable vtune domain support")
#endif // ENABLE_VTUNE_TRACEMARK
#ifdef ENABLE_VTUNE_JIT_INTERFACE
DEFINE_BOOL(enable_vtunejit, true, "enable vtune jit interface")
DEFINE_NEG_IMPLICATION(enable_vtunejit, compact_code_space)
#endif // ENABLE_VTUNE_JIT_INTERFACE
DEFINE_BOOL(experimental_report_exceptions_from_callbacks, true,
"Notify Api callback about exceptions thrown in Api callbacks")
// builtins.cc
DEFINE_BOOL(allow_unsafe_function_constructor, false,
"allow invoking the function constructor without security checks")
DEFINE_BOOL(force_slow_path, false, "always take the slow path for builtins")
DEFINE_BOOL(test_small_max_function_context_stub_size, false,
"enable testing the function context size overflow path "
"by making the maximum size smaller")
DEFINE_BOOL(inline_new, true, "use fast inline allocation")
DEFINE_NEG_NEG_IMPLICATION(inline_new, turbo_allocation_folding)
// bytecode-generator.cc
DEFINE_INT(switch_table_spread_threshold, 3,
"allow the jump table used for switch statements to span a range "
"of integers roughly equal to this number times the number of "
"clauses in the switch")
DEFINE_INT(switch_table_min_cases, 6,
"the number of Smi integer cases present in the switch statement "
"before using the jump table optimization")
// Note that enabling this stress mode might result in a failure to compile
// even a top-level code.
DEFINE_INT(stress_lazy_compilation, 0,
"stress lazy compilation by simulating stack overflow during "
"unoptimized bytecode generation with 1/n-th probability, "
"do nothing on 0")
// Correctness fuzzing treats stack overflows as crashes.
DEFINE_VALUE_IMPLICATION(correctness_fuzzer_suppressions,
stress_lazy_compilation, 0)
// codegen-ia32.cc / codegen-arm.cc
DEFINE_BOOL(trace, false, "trace javascript function calls")
// codegen.cc
DEFINE_BOOL(lazy, true, "use lazy compilation")
DEFINE_BOOL(lazy_eval, true, "use lazy compilation during eval")
DEFINE_BOOL(lazy_streaming, true,
"use lazy compilation during streaming compilation")
DEFINE_BOOL(max_lazy, false, "ignore eager compilation hints")
DEFINE_IMPLICATION(max_lazy, lazy)
DEFINE_BOOL(trace_opt, false, "trace optimized compilation")
DEFINE_BOOL(trace_opt_verbose, false,
"extra verbose optimized compilation tracing")
DEFINE_IMPLICATION(trace_opt_verbose, trace_opt)
DEFINE_BOOL(trace_opt_stats, false, "trace optimized compilation statistics")
DEFINE_BOOL(trace_deopt, false, "trace deoptimization")
DEFINE_BOOL(log_deopt, false, "log deoptimization")
DEFINE_BOOL(trace_deopt_verbose, false, "extra verbose deoptimization tracing")
DEFINE_IMPLICATION(trace_deopt_verbose, trace_deopt)
DEFINE_BOOL(trace_file_names, false,
"include file names in trace-opt/trace-deopt output")
DEFINE_BOOL(always_turbofan, false, "always try to optimize functions")
DEFINE_IMPLICATION(always_turbofan, turbofan)
DEFINE_BOOL(always_osr, false, "always try to OSR functions")
DEFINE_BOOL(prepare_always_turbofan, false, "prepare for turning on always opt")
DEFINE_BOOL(trace_serializer, false, "print code serializer trace")
#ifdef DEBUG
DEFINE_BOOL(external_reference_stats, false,
"print statistics on external references used during serialization")
#endif // DEBUG
// compilation-cache.cc
DEFINE_BOOL(compilation_cache, true, "enable compilation cache")
DEFINE_BOOL(cache_prototype_transitions, true, "cache prototype transitions")
// lazy-compile-dispatcher.cc
DEFINE_EXPERIMENTAL_FEATURE(lazy_compile_dispatcher,
"enable compiler dispatcher")
DEFINE_UINT(lazy_compile_dispatcher_max_threads, 0,
"max threads for compiler dispatcher (0 for unbounded)")
DEFINE_BOOL(trace_compiler_dispatcher, false,
"trace compiler dispatcher activity")
DEFINE_EXPERIMENTAL_FEATURE(
parallel_compile_tasks_for_eager_toplevel,
"spawn parallel compile tasks for eagerly compiled, top-level functions")
DEFINE_IMPLICATION(parallel_compile_tasks_for_eager_toplevel,
lazy_compile_dispatcher)
DEFINE_EXPERIMENTAL_FEATURE(
parallel_compile_tasks_for_lazy,
"spawn parallel compile tasks for all lazily compiled functions")
DEFINE_IMPLICATION(parallel_compile_tasks_for_lazy, lazy_compile_dispatcher)
// cpu-profiler.cc
DEFINE_INT(cpu_profiler_sampling_interval, 1000,
"CPU profiler sampling interval in microseconds")
// debugger
DEFINE_BOOL(
trace_side_effect_free_debug_evaluate, false,
"print debug messages for side-effect-free debug-evaluate for testing")
DEFINE_BOOL(hard_abort, true, "abort by crashing")
DEFINE_NEG_IMPLICATION(fuzzing, hard_abort)
DEFINE_NEG_IMPLICATION(hole_fuzzing, hard_abort)
DEFINE_NEG_IMPLICATION(sandbox_fuzzing, hard_abort)
// disassembler
DEFINE_BOOL(log_colour, ENABLE_LOG_COLOUR,
"When logging, try to use coloured output.")
// inspector
DEFINE_BOOL(expose_inspector_scripts, false,
"expose injected-script-source.js for debugging")
// execution.cc
DEFINE_INT(stack_size, V8_DEFAULT_STACK_SIZE_KB,
"default size of stack region v8 is allowed to use (in kBytes)")
// frames.cc
DEFINE_INT(max_stack_trace_source_length, 300,
"maximum length of function source code printed in a stack trace.")
// execution.cc, messages.cc
DEFINE_BOOL(clear_exceptions_on_js_entry, false,
"clear exceptions when entering JavaScript")
DEFINE_BOOL(use_original_message_for_stack_trace, true,
"use the message with which the Error constructor was called "
"rather than the value of the \"message\" property for Error.stack")
// counters.cc
DEFINE_INT(histogram_interval, 600000,
"time interval in ms for aggregating memory histograms")
// heap-snapshot-generator.cc
DEFINE_BOOL(heap_profiler_trace_objects, false,
"Dump heap object allocations/movements/size_updates")
DEFINE_BOOL(heap_profiler_use_embedder_graph, true,
"Use the new EmbedderGraph API to get embedder nodes")
DEFINE_BOOL(heap_snapshot_on_oom, false,
"Write a heap snapshot to disk on last-resort GCs")
DEFINE_INT(heap_snapshot_on_gc, -1,
"Write a heap snapshot to disk on a certain GC invocation")
DEFINE_UINT(heap_snapshot_string_limit, 1024,
"truncate strings to this length in the heap snapshot")
DEFINE_BOOL(heap_profiler_show_hidden_objects, false,
"use 'native' rather than 'hidden' node type in snapshot")
DEFINE_BOOL(profile_heap_snapshot, false, "dump time spent on heap snapshot")
#ifdef V8_ENABLE_HEAP_SNAPSHOT_VERIFY
DEFINE_BOOL(heap_snapshot_verify, false,
"verify that heap snapshot matches marking visitor behavior")
DEFINE_IMPLICATION(enable_slow_asserts, heap_snapshot_verify)
#endif
// sampling-heap-profiler.cc
DEFINE_BOOL(sampling_heap_profiler_suppress_randomness, false,
"Use constant sample intervals to eliminate test flakiness")
// ic.cc
DEFINE_BOOL(log_ic, false,
"Log inline cache state transitions for tools/ic-processor")
DEFINE_IMPLICATION(log_ic, log_code)
DEFINE_GENERIC_IMPLICATION(
log_ic, TracingFlags::ic_stats.store(
v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE))
DEFINE_BOOL_READONLY(fast_map_update, false,
"enable fast map update by caching the migration target")
#define DEFAULT_MAX_POLYMORPHIC_MAP_COUNT 4
DEFINE_INT(max_valid_polymorphic_map_count, DEFAULT_MAX_POLYMORPHIC_MAP_COUNT,
"maximum number of valid maps to track in POLYMORPHIC state")
DEFINE_BOOL(
clone_object_sidestep_transitions, true,
"support sidestep transitions for dependency tracking object clone maps")
DEFINE_WEAK_IMPLICATION(future, clone_object_sidestep_transitions)
// map-inl.h
DEFINE_INT(fast_properties_soft_limit, 12,
"limits the number of properties that can be added to an object "
"using keyed store before transitioning to dictionary mode")
DEFINE_INT(max_fast_properties, 128,
"limits the number of mutable properties that can be added to an "
"object before transitioning to dictionary mode")
DEFINE_BOOL(native_code_counters, DEBUG_BOOL,
"generate extra code for manipulating stats counters")
DEFINE_BOOL(super_ic, true, "use an IC for super property loads")
DEFINE_BOOL(mega_dom_ic, false, "use MegaDOM IC state for API objects")
// objects.cc
DEFINE_BOOL(trace_prototype_users, false,
"Trace updates to prototype user tracking")
DEFINE_BOOL(trace_for_in_enumerate, false, "Trace for-in enumerate slow-paths")
DEFINE_BOOL(log_maps, false, "Log map creation")
DEFINE_BOOL(log_maps_details, true, "Also log map details")
DEFINE_IMPLICATION(log_maps, log_code)
DEFINE_BOOL_READONLY(
move_prototype_transitions_first, true,
"Always move prototype transitions to the front of the tree")
// parser.cc
DEFINE_BOOL(allow_natives_syntax, false, "allow natives syntax")
DEFINE_BOOL(allow_natives_for_differential_fuzzing, false,
"allow only natives explicitly allowlisted for differential "
"fuzzers")
DEFINE_IMPLICATION(allow_natives_for_differential_fuzzing, allow_natives_syntax)
DEFINE_IMPLICATION(allow_natives_for_differential_fuzzing, fuzzing)
DEFINE_BOOL(parse_only, false, "only parse the sources")
// simulator-arm.cc and simulator-arm64.cc.
#ifdef USE_SIMULATOR
DEFINE_BOOL(trace_sim, false, "Trace simulator execution")
DEFINE_BOOL(debug_sim, false, "Enable debugging the simulator")
DEFINE_BOOL(check_icache, false,
"Check icache flushes in ARM and MIPS simulator")
DEFINE_INT(stop_sim_at, 0, "Simulator stop after x number of instructions")
#if defined(V8_TARGET_ARCH_ARM64) || defined(V8_TARGET_ARCH_MIPS64) || \
defined(V8_TARGET_ARCH_PPC64) || defined(V8_TARGET_ARCH_RISCV64) || \
defined(V8_TARGET_ARCH_LOONG64)
DEFINE_INT(sim_stack_alignment, 16,
"Stack alignment in bytes in simulator. This must be a power of two "
"and it must be at least 16. 16 is default.")
#else
DEFINE_INT(sim_stack_alignment, 8,
"Stack alingment in bytes in simulator (4 or 8, 8 is default)")
#endif
DEFINE_INT(sim_stack_size, 2 * MB / KB,
"Stack size of the ARM64, MIPS64 and PPC64 simulator "
"in kBytes (default is 2 MB)")
DEFINE_BOOL(trace_sim_messages, false,
"Trace simulator debug messages. Implied by --trace-sim.")
#endif // USE_SIMULATOR
#if defined V8_TARGET_ARCH_ARM64
// pointer-auth-arm64.cc
DEFINE_BOOL(sim_abort_on_bad_auth, true,
"Stop execution when a pointer authentication fails in the "
"ARM64 simulator.")
#endif
// isolate.cc
DEFINE_BOOL(async_stack_traces, true,
"include async stack traces in Error.stack")
DEFINE_BOOL(stack_trace_on_illegal, false,
"print stack trace when an illegal exception is thrown")
DEFINE_BOOL(abort_on_uncaught_exception, false,
"abort program (dump core) when an uncaught exception is thrown")
DEFINE_BOOL(correctness_fuzzer_suppressions, false,
"Suppress certain unspecified behaviors to ease correctness "
"fuzzing: Abort program when the stack overflows or a string "
"exceeds maximum length (as opposed to throwing RangeError). "
"Use a fixed suppression string for error messages.")
DEFINE_BOOL(rehash_snapshot, false,
"rehash strings from the snapshot to override the baked-in seed")
DEFINE_UINT64(hash_seed, 0,
"Fixed seed to use to hash property keys (0 means random)"
"(with snapshots this option cannot override the baked-in seed)")
DEFINE_INT(random_seed, 0,
"Default seed for initializing random generator "
"(0, the default, means to use system random).")
DEFINE_INT(fuzzer_random_seed, 0,
"Default seed for initializing fuzzer random generator "
"(0, the default, means to use v8's random number generator seed).")
DEFINE_BOOL(trace_rail, false, "trace RAIL mode")
DEFINE_BOOL(print_all_exceptions, false,
"print exception object and stack trace on each thrown exception")
DEFINE_BOOL(
detailed_error_stack_trace, false,
"includes arguments for each function call in the error stack frames array")
DEFINE_BOOL(adjust_os_scheduling_parameters, true,
"adjust OS specific scheduling params for the isolate")
DEFINE_BOOL(experimental_flush_embedded_blob_icache, true,
"Used in an experiment to evaluate icache flushing on certain CPUs")
DEFINE_BOOL(allow_allocation_in_fast_api_call, true,
"Allow allocations in fast API calls.")
// Flags for short builtin calls feature
#if V8_SHORT_BUILTIN_CALLS
#define V8_SHORT_BUILTIN_CALLS_BOOL true
#else
#define V8_SHORT_BUILTIN_CALLS_BOOL false
#endif
DEFINE_BOOL(short_builtin_calls, V8_SHORT_BUILTIN_CALLS_BOOL,
"Put embedded builtins code into the code range for shorter "
"builtin calls/jumps if system has >=4GB memory")
DEFINE_BOOL(trace_code_range_allocation, false,
"Trace code range allocation process.")
#ifdef V8_TARGET_OS_CHROMEOS
#define V8_TARGET_OS_CHROMEOS_BOOL true
#else
#define V8_TARGET_OS_CHROMEOS_BOOL false
#endif // V8_TARGET_OS_CHROMEOS
// TODO(1417652): Enable on ChromeOS once the issue is fixed.
DEFINE_BOOL(
better_code_range_allocation,
V8_EXTERNAL_CODE_SPACE_BOOL&& COMPRESS_POINTERS_IN_SHARED_CAGE_BOOL &&
!V8_TARGET_OS_CHROMEOS_BOOL,
"This mode tries harder to allocate code range near .text section. "
"Works only for configurations with external code space and "
"shared pointer compression cage.")
DEFINE_BOOL(abort_on_far_code_range, false,
"Abort if code range is allocated further away than 4GB from the"
".text section")
// runtime.cc
DEFINE_BOOL(runtime_call_stats, false, "report runtime call counts and times")
DEFINE_GENERIC_IMPLICATION(
runtime_call_stats,
TracingFlags::runtime_stats.store(
v8::tracing::TracingCategoryObserver::ENABLED_BY_NATIVE))
DEFINE_BOOL(rcs, false, "report runtime call counts and times")
DEFINE_IMPLICATION(rcs, runtime_call_stats)
DEFINE_BOOL(rcs_cpu_time, false,
"report runtime times in cpu time (the default is wall time)")
DEFINE_IMPLICATION(rcs_cpu_time, rcs)
// snapshot-common.cc
DEFINE_BOOL(verify_snapshot_checksum, DEBUG_BOOL,
"Verify snapshot checksums when deserializing snapshots. Enable "
"checksum creation and verification for code caches. Enabled by "
"default in debug builds and once per process for Android.")
DEFINE_BOOL(profile_deserialization, false,
"Print the time it takes to deserialize the snapshot.")
DEFINE_BOOL(trace_deserialization, false, "Trace the snapshot deserialization.")
DEFINE_BOOL(serialization_statistics, false,
"Collect statistics on serialized objects.")
// Regexp
DEFINE_BOOL(regexp_optimization, true, "generate optimized regexp code")
DEFINE_BOOL(regexp_interpret_all, false, "interpret all regexp code")
#ifdef V8_TARGET_BIG_ENDIAN
#define REGEXP_PEEPHOLE_OPTIMIZATION_BOOL false
#else
#define REGEXP_PEEPHOLE_OPTIMIZATION_BOOL true
#endif
DEFINE_BOOL(regexp_tier_up, true,
"enable regexp interpreter and tier up to the compiler after the "
"number of executions set by the tier up ticks flag")
DEFINE_NEG_IMPLICATION(regexp_interpret_all, regexp_tier_up)
DEFINE_INT(regexp_tier_up_ticks, 1,
"set the number of executions for the regexp interpreter before "
"tiering-up to the compiler")
DEFINE_BOOL(regexp_peephole_optimization, REGEXP_PEEPHOLE_OPTIMIZATION_BOOL,
"enable peephole optimization for regexp bytecode")
DEFINE_BOOL(regexp_results_cache, true, "enable the regexp results cache")
DEFINE_BOOL(trace_regexp_peephole_optimization, false,
"trace regexp bytecode peephole optimization")
DEFINE_BOOL(trace_regexp_bytecodes, false, "trace regexp bytecode execution")
DEFINE_BOOL(trace_regexp_assembler, false,
"trace regexp macro assembler calls.")
DEFINE_BOOL(trace_regexp_parser, false, "trace regexp parsing")
DEFINE_BOOL(trace_regexp_tier_up, false, "trace regexp tiering up execution")
DEFINE_BOOL(trace_regexp_graph, false, "trace the regexp graph")
DEFINE_BOOL(enable_experimental_regexp_engine, false,
"recognize regexps with 'l' flag, run them on experimental engine")
DEFINE_BOOL(default_to_experimental_regexp_engine, false,
"run regexps with the experimental engine where possible")
DEFINE_IMPLICATION(default_to_experimental_regexp_engine,
enable_experimental_regexp_engine)
DEFINE_BOOL(experimental_regexp_engine_capture_group_opt, false,
"enable time optimizations for the experimental regexp engine")
DEFINE_IMPLICATION(experimental_regexp_engine_capture_group_opt,
enable_experimental_regexp_engine)
DEFINE_UINT64(experimental_regexp_engine_capture_group_opt_max_memory_usage,
1024,
"maximum memory usage in MB allowed for experimental engine")
DEFINE_BOOL(trace_experimental_regexp_engine, false,
"trace execution of experimental regexp engine")
DEFINE_BOOL(enable_experimental_regexp_engine_on_excessive_backtracks, false,
"fall back to a breadth-first regexp engine on excessive "
"backtracking")
DEFINE_UINT(regexp_backtracks_before_fallback, 50000,
"number of backtracks during regexp execution before fall back "
"to experimental engine if "
"enable_experimental_regexp_engine_on_excessive_backtracks is set")
#if V8_TARGET_ARCH_X64 || V8_TARGET_ARCH_ARM64
DEFINE_BOOL(regexp_simd, true, "enable SIMD for regexp jit code")
#else
DEFINE_BOOL_READONLY(
regexp_simd, false,
"enable SIMD for regexp jit code (not supported for this architecture)")
#endif // V8_TARGET_ARCH_X64 || V8_TARGET_ARCH_ARM64
DEFINE_BOOL(trace_read_only_promotion, false,
"trace the read-only promotion pass")
DEFINE_BOOL(trace_read_only_promotion_verbose, false,
"trace the read-only promotion pass")
DEFINE_WEAK_IMPLICATION(trace_read_only_promotion_verbose,
trace_read_only_promotion)
// Testing flags test/cctest/test-{flags,api,serialization}.cc
DEFINE_BOOL(testing_bool_flag, true, "testing_bool_flag")
DEFINE_MAYBE_BOOL(testing_maybe_bool_flag, "testing_maybe_bool_flag")
DEFINE_INT(testing_int_flag, 13, "testing_int_flag")
DEFINE_FLOAT(testing_float_flag, 2.5, "float-flag")
DEFINE_STRING(testing_string_flag, "Hello, world!", "string-flag")
DEFINE_INT(testing_prng_seed, 42, "Seed used for threading test randomness")
// Test flag for a check in %OptimizeFunctionOnNextCall
DEFINE_BOOL(
testing_d8_test_runner, false,
"test runner turns on this flag to enable a check that the function was "
"prepared for optimization before marking it for optimization")
DEFINE_EXPERIMENTAL_FEATURE(
strict_termination_checks,
"Enable strict terminating DCHECKs to prevent accidentally "
"keeping on executing JS after terminating V8.")
DEFINE_BOOL(
fuzzing, false,
"Fuzzers use this flag to signal that they are ... fuzzing. This causes "
"intrinsics to fail silently (e.g. return undefined) on invalid usage.")
// When fuzzing, always compile functions twice and ensure that the generated
// bytecode is the same. This can help find bugs such as crbug.com/1394403 as it
// avoids the need for bytecode aging to kick in to trigger the recomplication.
DEFINE_WEAK_NEG_IMPLICATION(fuzzing, lazy)
DEFINE_WEAK_IMPLICATION(fuzzing, stress_lazy_source_positions)
DEFINE_BOOL(
hole_fuzzing, false,
"Fuzzers use this flag to turn DCHECKs into NOPs and CHECK failures into "
"silent exits. This is useful if we want to find memory corruption "
"primitives with a leaked hole, where the engine is already in a weird "
"state")
//
// Sandbox-related flags.
//
#ifdef V8_ENABLE_SANDBOX
DEFINE_BOOL(sandbox_testing, false,
"Enable sandbox testing mode. This exposes the memory corruption "
"API (if available) and enables the sandbox crash filter to "
"terminate the process (with status zero) if a crash that does not "
"represent a sandbox violation is detected.")
#else
DEFINE_BOOL_READONLY(
sandbox_testing, false,
"Enable sandbox testing mode. This exposes the memory corruption API (if "
"available) and enables the sandbox crash filter to terminate the process "
"(with status zero) if a crash that does not represent a sandbox violation "
"is detected.")
#endif
#ifdef V8_ENABLE_MEMORY_CORRUPTION_API
// Sandbox fuzzing mode requires the memory corruption API.
DEFINE_BOOL(sandbox_fuzzing, false,
"Enable sandbox fuzzing mode. This exposes the memory corruption "
"API and enables the sandbox crash filter to terminate the process "
"(with non-zero status) if a crash that does not represent a "
"sandbox violation is detected.")
#else
DEFINE_BOOL_READONLY(sandbox_fuzzing, false,
"Enable sandbox fuzzing mode. This exposes the memory "
"corruption API and enables the sandbox crash filter to "
"terminate the process (with non-zero status) if a crash "
"that does not represent a sandbox violation is detected.")
#endif
// Only one of these can be enabled.
DEFINE_NEG_IMPLICATION(sandbox_fuzzing, sandbox_testing)
DEFINE_NEG_IMPLICATION(sandbox_testing, sandbox_fuzzing)
#ifdef V8_ENABLE_MEMORY_CORRUPTION_API
DEFINE_BOOL(expose_memory_corruption_api, false,
"Exposes the memory corruption API. Set automatically by "
"--sandbox-testing and --sandbox-fuzzing.")
DEFINE_IMPLICATION(sandbox_fuzzing, expose_memory_corruption_api)
DEFINE_IMPLICATION(sandbox_testing, expose_memory_corruption_api)
#else
DEFINE_BOOL_READONLY(expose_memory_corruption_api, false,
"Exposes the memory corruption API. Set automatically by "
"--sandbox-testing and --sandbox-fuzzing.")
#endif
#if defined(V8_OS_AIX) && defined(COMPONENT_BUILD)
// FreezeFlags relies on mprotect() method, which does not work by default on
// shared mem: https://www.ibm.com/docs/en/aix/7.2?topic=m-mprotect-subroutine
DEFINE_BOOL(freeze_flags_after_init, false,
"Disallow changes to flag values after initializing V8")
#else
DEFINE_BOOL(freeze_flags_after_init, true,
"Disallow changes to flag values after initializing V8")
#endif // defined(V8_OS_AIX) && defined(COMPONENT_BUILD)
#if V8_ENABLE_CET_SHADOW_STACK
#define V8_CET_SHADOW_STACK_BOOL true
#else
#define V8_CET_SHADOW_STACK_BOOL false
#endif
DEFINE_BOOL(cet_compatible, V8_CET_SHADOW_STACK_BOOL,
"Generate Intel CET compatible code")
DEFINE_NEG_IMPLICATION(cet_compatible, compact_code_space_with_stack)
// mksnapshot.cc
DEFINE_STRING(embedded_src, nullptr,
"Path for the generated embedded data file. (mksnapshot only)")
DEFINE_STRING(
embedded_variant, nullptr,
"Label to disambiguate symbols in embedded data file. (mksnapshot only)")
#if V8_STATIC_ROOTS_GENERATION_BOOL
DEFINE_STRING(static_roots_src, nullptr,
"Path for writing a fresh static-roots.h. (mksnapshot only, "
"build without static roots only)")
#endif
DEFINE_STRING(startup_src, nullptr,
"Write V8 startup as C++ src. (mksnapshot only)")
DEFINE_STRING(startup_blob, nullptr,
"Write V8 startup blob file. (mksnapshot only)")
DEFINE_STRING(target_arch, nullptr,
"The mksnapshot target arch. (mksnapshot only)")
DEFINE_STRING(target_os, nullptr, "The mksnapshot target os. (mksnapshot only)")
DEFINE_BOOL(target_is_simulator, false,
"Instruct mksnapshot that the target is meant to run in the "
"simulator and it can generate simulator-specific instructions. "
"(mksnapshot only)")
DEFINE_STRING(turbo_profiling_input, nullptr,
"Path of the input file containing basic information for "
"builtins. (mksnapshot only)")
DEFINE_STRING(turbo_log_builtins_count_input, nullptr,
"Path of the input file containing basic block counters for "
"builtins for logging in turbolizer. (mksnapshot only)")
// On some platforms, the .text section only has execute permissions.
DEFINE_BOOL(text_is_readable, true,
"Whether the .text section of binary can be read")
DEFINE_NEG_NEG_IMPLICATION(text_is_readable, partial_constant_pool)
//
// Minor mark sweep collector flags.
//
DEFINE_BOOL(trace_minor_ms_parallel_marking, false,
"trace parallel marking for the young generation")
DEFINE_BOOL(minor_ms, false, "perform young generation mark sweep GCs")
DEFINE_IMPLICATION(minor_ms, separate_gc_phases)
DEFINE_IMPLICATION(minor_ms, page_promotion)
DEFINE_BOOL(concurrent_minor_ms_marking, true,
"perform young generation marking concurrently")
DEFINE_NEG_NEG_IMPLICATION(concurrent_marking, concurrent_minor_ms_marking)
#ifdef V8_ENABLE_BLACK_ALLOCATED_PAGES
#define V8_ENABLE_BLACK_ALLOCATED_PAGES_BOOL true
#else
#define V8_ENABLE_BLACK_ALLOCATED_PAGES_BOOL false
#endif
DEFINE_BOOL_READONLY(
black_allocated_pages, V8_ENABLE_BLACK_ALLOCATED_PAGES_BOOL,
"allocate non-young objects during incremental marking on separate pages")
#ifdef V8_ENABLE_STICKY_MARK_BITS
#define V8_ENABLE_STICKY_MARK_BITS_BOOL true
#if V8_ENABLE_BLACK_ALLOCATED_PAGES_BOOL
#error "Black allocated pages are not supported with sticky mark bits"
#endif // V8_ENABLE_BLACK_ALLOCATED_PAGES_BOOL
#else
#define V8_ENABLE_STICKY_MARK_BITS_BOOL false
#endif
DEFINE_BOOL_READONLY(sticky_mark_bits, V8_ENABLE_STICKY_MARK_BITS_BOOL,
"use sticky mark bits for separation of generations")
DEFINE_IMPLICATION(sticky_mark_bits, minor_ms)
// TODO(333906585): Copy mark bits and live bytes on compaction.
DEFINE_NEG_IMPLICATION(sticky_mark_bits, compact)
#ifndef DEBUG
#define V8_MINOR_MS_CONCURRENT_MARKING_MIN_CAPACITY_DEFAULT 8
#else
#define V8_MINOR_MS_CONCURRENT_MARKING_MIN_CAPACITY_DEFAULT 0
#endif
DEFINE_UINT(minor_ms_min_new_space_capacity_for_concurrent_marking_mb,
V8_MINOR_MS_CONCURRENT_MARKING_MIN_CAPACITY_DEFAULT,
"min new space capacity in MBs for using young generation "
"concurrent marking.")
DEFINE_UINT(minor_ms_concurrent_marking_trigger, 90,
"minor ms concurrent marking trigger in percent of the current new "
"space capacity")
DEFINE_SIZE_T(minor_ms_min_lab_size_kb, 0,
"override for the minimum lab size in KB to be used for new "
"space allocations with minor ms. ")
//
// Dev shell flags
//
DEFINE_BOOL(help, false, "Print usage message, including flags, on console")
DEFINE_BOOL(print_flag_values, false, "Print all flag values of V8")
// Slow histograms are also enabled via --dump-counters in d8.
DEFINE_BOOL(slow_histograms, false,
"Enable slow histograms with more overhead.")
DEFINE_BOOL(use_external_strings, false, "Use external strings for source code")
DEFINE_STRING(map_counters, "", "Map counters to a file")
DEFINE_BOOL(mock_arraybuffer_allocator, false,
"Use a mock ArrayBuffer allocator for testing.")
DEFINE_SIZE_T(mock_arraybuffer_allocator_limit, 0,
"Memory limit for mock ArrayBuffer allocator used to simulate "
"OOM for testing.")
#ifdef V8_OS_LINUX
DEFINE_BOOL(multi_mapped_mock_allocator, false,
"Use a multi-mapped mock ArrayBuffer allocator for testing.")
#endif
//
// GDB JIT integration flags.
//
#undef FLAG
#ifdef ENABLE_GDB_JIT_INTERFACE
#define FLAG FLAG_FULL
#else
#define FLAG FLAG_READONLY
#endif
DEFINE_BOOL(gdbjit, false, "enable GDBJIT interface")
DEFINE_BOOL(gdbjit_full, false, "enable GDBJIT interface for all code objects")
DEFINE_BOOL(gdbjit_dump, false, "dump elf objects with debug info to disk")
DEFINE_STRING(gdbjit_dump_filter, "",
"dump only objects containing this substring")
#ifdef ENABLE_GDB_JIT_INTERFACE
DEFINE_IMPLICATION(gdbjit_full, gdbjit)
DEFINE_IMPLICATION(gdbjit_dump, gdbjit)
#endif
DEFINE_NEG_IMPLICATION(gdbjit, compact_code_space)
//
// Debug only flags
//
#undef FLAG
#ifdef DEBUG
#define FLAG FLAG_FULL
#else
#define FLAG FLAG_READONLY
#endif
#ifdef ENABLE_SLOW_DCHECKS
DEFINE_BOOL(enable_slow_asserts, true,
"enable asserts that are slow to execute")
#else
DEFINE_BOOL_READONLY(enable_slow_asserts, false,
"enable asserts that are slow to execute")
#endif
// codegen-ia32.cc / codegen-arm.cc / macro-assembler-*.cc
DEFINE_BOOL(print_ast, false, "print source AST")
DEFINE_BOOL(trap_on_abort, false, "replace aborts by breakpoints")
// compiler.cc
DEFINE_BOOL(print_scopes, false, "print scopes")
// contexts.cc
DEFINE_BOOL(trace_contexts, false, "trace contexts operations")
// heap.cc
DEFINE_BOOL(gc_verbose, false, "print stuff during garbage collection")
DEFINE_BOOL(code_stats, false, "report code statistics after GC")
DEFINE_BOOL(print_handles, false, "report handles after GC")
DEFINE_BOOL(check_handle_count, false,
"Check that there are not too many handles at GC")
DEFINE_BOOL(print_global_handles, false, "report global handles after GC")
// TurboFan debug-only flags.
DEFINE_BOOL(trace_turbo_escape, false, "enable tracing in escape analysis")
// objects.cc
DEFINE_BOOL(trace_module_status, false,
"Trace status transitions of ECMAScript modules")
DEFINE_BOOL(trace_normalization, false,
"prints when objects are turned into dictionaries.")
// runtime.cc
DEFINE_BOOL(trace_lazy, false, "trace lazy compilation")
// spaces.cc
DEFINE_BOOL(trace_isolates, false, "trace isolate state changes")
// Regexp
DEFINE_BOOL(regexp_possessive_quantifier, false,
"enable possessive quantifier syntax for testing")
// Debugger
DEFINE_BOOL(print_break_location, false, "print source location on debug break")
//
// Logging and profiling flags
//
// Logging flag dependencies are also set separately in
// V8::InitializeOncePerProcessImpl. Please add your flag to the log_all_flags
// list in v8.cc to properly set v8_flags.log and automatically enable it with
// --log-all.
#undef FLAG
#define FLAG FLAG_FULL
// log.cc
DEFINE_STRING(logfile, "v8.log",
"Specify the name of the log file, use '-' for console, '+' for "
"a temporary file.")
DEFINE_BOOL(logfile_per_isolate, true, "Separate log files for each isolate.")
DEFINE_BOOL(log, false,
"Minimal logging (no API, code, GC, suspect, or handles samples).")
DEFINE_BOOL(log_all, false, "Log all events to the log file.")
DEFINE_BOOL(log_internal_timer_events, false, "See --log-timer-events")
DEFINE_BOOL(log_timer_events, false,
"Log timer events (incl. console.time* and Date.now).")
DEFINE_BOOL(log_source_code, false, "Log source code.")
DEFINE_BOOL(log_source_position, false, "Log detailed source information.")
DEFINE_BOOL(log_code, false,
"Log code events to the log file without profiling.")
DEFINE_WEAK_IMPLICATION(log_code, log_source_code)
DEFINE_WEAK_IMPLICATION(log_code, log_source_position)
DEFINE_BOOL(log_feedback_vector, false, "Log FeedbackVectors on first creation")
DEFINE_BOOL(log_code_disassemble, false,
"Log all disassembled code to the log file.")
DEFINE_IMPLICATION(log_code_disassemble, log_code)
DEFINE_BOOL(log_function_events, false,
"Log function events "
"(parse, compile, execute) separately.")
DEFINE_BOOL(detailed_line_info, false,
"Always generate detailed line information for CPU profiling.")
DEFINE_BOOL(perfetto_code_logger, false,
"Enable the Perfetto code data source.")
#if defined(ANDROID)
// Phones and tablets have processors that are much slower than desktop
// and laptop computers for which current heuristics are tuned.
#define DEFAULT_PROF_SAMPLING_INTERVAL 5000
#else
#define DEFAULT_PROF_SAMPLING_INTERVAL 1000
#endif
DEFINE_INT(prof_sampling_interval, DEFAULT_PROF_SAMPLING_INTERVAL,
"Interval for --prof samples (in microseconds).")
#undef DEFAULT_PROF_SAMPLING_INTERVAL
DEFINE_BOOL(prof_cpp, false, "Like --prof, but ignore generated code.")
DEFINE_BOOL(prof_browser_mode, true,
"Used with --prof, turns on browser-compatible mode for profiling.")
DEFINE_BOOL(prof, false,
"Log statistical profiling information (implies --log-code).")
DEFINE_IMPLICATION(prof, prof_cpp)
DEFINE_IMPLICATION(prof, log_code)
DEFINE_BOOL(ll_prof, false, "Enable low-level linux profiler.")
#if V8_OS_LINUX
#define DEFINE_PERF_PROF_BOOL(nam, cmt) DEFINE_BOOL(nam, false, cmt)
#define DEFINE_PERF_PROF_IMPLICATION DEFINE_IMPLICATION
#else
#define DEFINE_PERF_PROF_BOOL(nam, cmt) DEFINE_BOOL_READONLY(nam, false, cmt)
#define DEFINE_PERF_PROF_IMPLICATION(...)
#endif
#if defined(ANDROID)
#define DEFAULT_PERF_BASIC_PROF_PATH "/data/local/tmp"
#define DEFAULT_PERF_PROF_PATH DEFAULT_PERF_BASIC_PROF_PATH
#else
#define DEFAULT_PERF_BASIC_PROF_PATH "/tmp"
#define DEFAULT_PERF_PROF_PATH "."
#endif
DEFINE_PERF_PROF_BOOL(perf_basic_prof,
"Enable perf linux profiler (basic support).")
DEFINE_NEG_IMPLICATION(perf_basic_prof, compact_code_space)
DEFINE_STRING(perf_basic_prof_path, DEFAULT_PERF_BASIC_PROF_PATH,
"directory to write perf-<pid>.map symbol file to")
DEFINE_PERF_PROF_BOOL(
perf_basic_prof_only_functions,
"Only report function code ranges to perf (i.e. no stubs).")
DEFINE_PERF_PROF_IMPLICATION(perf_basic_prof_only_functions, perf_basic_prof)
DEFINE_PERF_PROF_BOOL(
perf_prof, "Enable perf linux profiler (experimental annotate support).")
DEFINE_STRING(perf_prof_path, DEFAULT_PERF_PROF_PATH,
"directory to write jit-<pid>.dump symbol file to")
DEFINE_PERF_PROF_BOOL(
perf_prof_annotate_wasm,
"Used with --perf-prof, load wasm source map and provide annotate "
"support (experimental).")
DEFINE_PERF_PROF_BOOL(
perf_prof_delete_file,
"Remove the perf file right after creating it (for testing only).")
DEFINE_NEG_IMPLICATION(perf_prof, compact_code_space)
// --perf-prof-unwinding-info is available only on selected architectures.
#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_ARM64 || V8_TARGET_ARCH_X64 || \
V8_TARGET_ARCH_S390X || V8_TARGET_ARCH_PPC64
DEFINE_PERF_PROF_BOOL(
perf_prof_unwinding_info,
"Enable unwinding info for perf linux profiler (experimental).")
DEFINE_PERF_PROF_IMPLICATION(perf_prof, perf_prof_unwinding_info)
#else
DEFINE_BOOL_READONLY(
perf_prof_unwinding_info, false,
"Enable unwinding info for perf linux profiler (experimental).")
#endif
#undef DEFINE_PERF_PROF_BOOL
#undef DEFINE_PERF_PROF_IMPLICATION
DEFINE_STRING(gc_fake_mmap, "/tmp/__v8_gc__",
"Specify the name of the file for fake gc mmap used in ll_prof")
DEFINE_BOOL(redirect_code_traces, false,
"output deopt information and disassembly into file "
"code-<pid>-<isolate id>.asm")
DEFINE_STRING(redirect_code_traces_to, nullptr,
"output deopt information and disassembly into the given file")
DEFINE_BOOL(print_opt_source, false,
"print source code of optimized and inlined functions")
DEFINE_BOOL(vtune_prof_annotate_wasm, false,
"Used when v8_enable_vtunejit is enabled, load wasm source map and "
"provide annotate support (experimental).")
DEFINE_BOOL(win64_unwinding_info, true, "Enable unwinding info for Windows/x64")
DEFINE_BOOL(interpreted_frames_native_stack, false,
"Show interpreted frames on the native stack (useful for external "
"profilers).")
#if defined(V8_ENABLE_ETW_STACK_WALKING)
DEFINE_BOOL(enable_etw_stack_walking, false,
"Enable etw stack walking for windows")
DEFINE_WEAK_IMPLICATION(future, enable_etw_stack_walking)
DEFINE_BOOL(etw_trace_debug, false,
"Enable etw debug logging (only on debug builds)")
DEFINE_BOOL(enable_etw_by_custom_filter_only, true,
"Enable etw stack walking for windows, but only if explicitly "
"specified in a WPR profile")
#else // V8_ENABLE_ETW_STACK_WALKING
DEFINE_BOOL_READONLY(enable_etw_stack_walking, false,
"Enable etw stack walking for windows")
DEFINE_BOOL_READONLY(etw_trace_debug, false,
"Enable etw debug logging (only on debug builds)")
DEFINE_BOOL_READONLY(
enable_etw_by_custom_filter_only, false,
"Enable etw stack walking for windows, but only if explicitly "
"specified in a WPR profile")
#endif // V8_ENABLE_ETW_STACK_WALKING
DEFINE_BOOL(print_builtin_size, false, "print code size for builtins")
//
// Disassembler only flags
//
#undef FLAG
#ifdef ENABLE_DISASSEMBLER
#define FLAG FLAG_FULL
#else
#define FLAG FLAG_READONLY
#endif
// elements.cc
DEFINE_BOOL(trace_elements_transitions, false, "trace elements transitions")
DEFINE_BOOL(trace_creation_allocation_sites, false,
"trace the creation of allocation sites")
DEFINE_BOOL(print_code, false, "print generated code")
DEFINE_BOOL(print_opt_code, false, "print optimized code")
DEFINE_STRING(print_opt_code_filter, "*", "filter for printing optimized code")
DEFINE_BOOL(print_code_verbose, false, "print more information for code")
DEFINE_BOOL(print_builtin_code, false, "print generated code for builtins")
DEFINE_STRING(print_builtin_code_filter, "*",
"filter for printing builtin code")
DEFINE_BOOL(print_regexp_code, false, "print generated regexp code")
DEFINE_BOOL(print_regexp_bytecode, false, "print generated regexp bytecode")
#ifdef ENABLE_DISASSEMBLER
DEFINE_BOOL(print_all_code, false, "enable all flags related to printing code")
DEFINE_IMPLICATION(print_all_code, print_code)
DEFINE_IMPLICATION(print_all_code, print_opt_code)
DEFINE_IMPLICATION(print_all_code, print_code_verbose)
DEFINE_IMPLICATION(print_all_code, print_builtin_code)
DEFINE_IMPLICATION(print_all_code, print_regexp_code)
#endif
#undef FLAG
#define FLAG FLAG_FULL
//
// Predictable mode related flags.
//
DEFINE_BOOL(predictable, false, "enable predictable mode")
DEFINE_NEG_IMPLICATION(predictable, memory_reducer)
// TODO(v8:11848): These flags were recursively implied via --single-threaded
// before. Audit them, and remove any unneeded implications.
DEFINE_IMPLICATION(predictable, single_threaded_gc)
DEFINE_NEG_IMPLICATION(predictable, concurrent_recompilation)
DEFINE_NEG_IMPLICATION(predictable, stress_concurrent_inlining)
DEFINE_NEG_IMPLICATION(predictable, lazy_compile_dispatcher)
DEFINE_NEG_IMPLICATION(predictable, parallel_compile_tasks_for_eager_toplevel)
DEFINE_NEG_IMPLICATION(predictable, parallel_compile_tasks_for_lazy)
#ifdef V8_ENABLE_MAGLEV
DEFINE_NEG_IMPLICATION(predictable, maglev_deopt_data_on_background)
DEFINE_NEG_IMPLICATION(predictable, maglev_build_code_on_background)
#endif // V8_ENABLE_MAGLEV
// Avoid random seeds in predictable mode.
DEFINE_BOOL(predictable_and_random_seed_is_0, true,
"predictable && (random_seed == 0)")
DEFINE_NEG_NEG_IMPLICATION(predictable, predictable_and_random_seed_is_0)
DEFINE_NEG_VALUE_VALUE_IMPLICATION(random_seed, 0,
predictable_and_random_seed_is_0, false)
DEFINE_VALUE_IMPLICATION(predictable_and_random_seed_is_0, random_seed, 12347)
DEFINE_BOOL(predictable_gc_schedule, false,
"Predictable garbage collection schedule. Fixes heap growing, "
"idle, and memory reducing behavior.")
DEFINE_VALUE_IMPLICATION(predictable_gc_schedule, min_semi_space_size,
size_t{4})
DEFINE_VALUE_IMPLICATION(predictable_gc_schedule, max_semi_space_size,
size_t{4})
DEFINE_VALUE_IMPLICATION(predictable_gc_schedule, heap_growing_percent, 30)
DEFINE_NEG_IMPLICATION(predictable_gc_schedule, memory_reducer)
//
// Threading related flags.
//
DEFINE_BOOL(single_threaded, false, "disable the use of background tasks")
DEFINE_IMPLICATION(single_threaded, single_threaded_gc)
DEFINE_NEG_IMPLICATION(single_threaded, concurrent_recompilation)
DEFINE_NEG_IMPLICATION(single_threaded, concurrent_builtin_generation)
DEFINE_NEG_IMPLICATION(single_threaded, stress_concurrent_inlining)
DEFINE_NEG_IMPLICATION(single_threaded, lazy_compile_dispatcher)
DEFINE_NEG_IMPLICATION(single_threaded,
parallel_compile_tasks_for_eager_toplevel)
DEFINE_NEG_IMPLICATION(single_threaded, parallel_compile_tasks_for_lazy)
#ifdef V8_ENABLE_MAGLEV
DEFINE_NEG_IMPLICATION(single_threaded, maglev_deopt_data_on_background)
DEFINE_NEG_IMPLICATION(single_threaded, maglev_build_code_on_background)
#endif // V8_ENABLE_MAGLEV
//
// Parallel and concurrent GC (Orinoco) related flags.
//
DEFINE_BOOL(single_threaded_gc, false, "disable the use of background gc tasks")
DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_marking)
DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_sweeping)
DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_compaction)
DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_marking)
DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_pointer_update)
DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_weak_ref_clearing)
DEFINE_NEG_IMPLICATION(single_threaded_gc, parallel_scavenge)
DEFINE_NEG_IMPLICATION(single_threaded_gc, concurrent_array_buffer_sweeping)
DEFINE_NEG_IMPLICATION(single_threaded_gc, stress_concurrent_allocation)
DEFINE_NEG_IMPLICATION(single_threaded_gc, cppheap_concurrent_marking)
DEFINE_BOOL(single_threaded_gc_in_background, true,
"disable the use of background gc tasks when in background")
DEFINE_BOOL(parallel_pause_for_gc_in_background, true,
"Use parallel threads in the atomic pause for background GCs")
DEFINE_BOOL(incremental_marking_for_gc_in_background, true,
"Use parallel threads in the atomic pause for background GCs")
DEFINE_BOOL(update_allocation_limits_after_loading, false,
"force recomputation of allocation limites when leaving the "
"loading RAIL mode (either on a RAIL mode change or incremental "
"marking start).")
DEFINE_EXPERIMENTAL_FEATURE(shared_heap,
"Enables a shared heap between isolates.")
#if defined(V8_USE_LIBM_TRIG_FUNCTIONS)
DEFINE_BOOL(use_libm_trig_functions, true, "use libm trig functions")
#endif
#undef FLAG
#ifdef VERIFY_PREDICTABLE
#define FLAG FLAG_FULL
#else
#define FLAG FLAG_READONLY
#endif
DEFINE_BOOL(verify_predictable, false,
"this mode is used for checking that V8 behaves predictably")
DEFINE_IMPLICATION(verify_predictable, predictable)
DEFINE_INT(dump_allocations_digest_at_alloc, -1,
"dump allocations digest each n-th allocation")
#define LOG_FLAGS(V) \
V(log_code) \
V(log_code_disassemble) \
V(log_deopt) \
V(log_feedback_vector) \
V(log_function_events) \
V(log_ic) \
V(log_maps) \
V(log_source_code) \
V(log_source_position) \
V(log_timer_events) \
V(prof) \
V(prof_cpp)
#define SET_IMPLICATIONS(V) \
DEFINE_IMPLICATION(log_all, V) \
DEFINE_IMPLICATION(V, log)
LOG_FLAGS(SET_IMPLICATIONS)
#undef SET_IMPLICATIONS
#undef LOG_FLAGS
DEFINE_IMPLICATION(log_all, log)
DEFINE_IMPLICATION(perf_prof, log)
DEFINE_IMPLICATION(perf_basic_prof, log)
DEFINE_IMPLICATION(ll_prof, log)
DEFINE_IMPLICATION(gdbjit, log)
// Cleanup...
#undef FLAG_FULL
#undef FLAG_READONLY
#undef FLAG
#undef FLAG_ALIAS
#undef DEFINE_BOOL
#undef DEFINE_MAYBE_BOOL
#undef DEFINE_DEBUG_BOOL
#undef DEFINE_INT
#undef DEFINE_STRING
#undef DEFINE_FLOAT
#undef DEFINE_IMPLICATION
#undef DEFINE_WEAK_IMPLICATION
#undef DEFINE_NEG_IMPLICATION
#undef DEFINE_NEG_IMPLICATION_WITH_WARNING
#undef DEFINE_WEAK_NEG_IMPLICATION
#undef DEFINE_NEG_NEG_IMPLICATION
#undef DEFINE_NEG_VALUE_IMPLICATION
#undef DEFINE_NEG_VALUE_VALUE_IMPLICATION
#undef DEFINE_VALUE_IMPLICATION
#undef DEFINE_MIN_VALUE_IMPLICATION
#undef DEFINE_DISABLE_FLAG_IMPLICATION
#undef DEFINE_WEAK_VALUE_IMPLICATION
#undef DEFINE_GENERIC_IMPLICATION
#undef DEFINE_REQUIREMENT
#undef DEFINE_ALIAS_BOOL
#undef DEFINE_ALIAS_INT
#undef DEFINE_ALIAS_STRING
#undef DEFINE_ALIAS_FLOAT
#undef FLAG_MODE_DECLARE
#undef FLAG_MODE_DEFINE_DEFAULTS
#undef FLAG_MODE_META
#undef FLAG_MODE_DEFINE_IMPLICATIONS
#undef FLAG_MODE_APPLY