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// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "gin/gin_features.h"
#include "base/metrics/field_trial_params.h"
namespace features {
// Enable code space compaction when finalizing a full GC with stack.
BASE_FEATURE(kV8CompactCodeSpaceWithStack,
("V8CompactCodeSpaceWithStack"),
kFeatureDefaultStateControlledByV8);
// Enable compaction when finalizing a full GC with stack.
BASE_FEATURE(kV8CompactWithStack,
("V8CompactWithStack"),
kFeatureDefaultStateControlledByV8);
// Decommit (rather than discard) pooled pages.
BASE_FEATURE(kV8DecommitPooledPages,
("DecommitPooledPages"),
kFeatureDefaultStateControlledByV8);
// Enables optimization of JavaScript in V8.
BASE_FEATURE(kV8OptimizeJavascript,
("V8OptimizeJavascript"),
kFeatureDefaultStateControlledByV8);
// Enables flushing of JS bytecode in V8.
BASE_FEATURE(kV8FlushBytecode,
("V8FlushBytecode"),
kFeatureDefaultStateControlledByV8);
const base::FeatureParam<int> kV8FlushBytecodeOldAge{
&kV8FlushBytecode, "V8FlushBytecodeOldAge", 5};
// Enables flushing of baseline code in V8.
BASE_FEATURE(kV8FlushBaselineCode,
("V8FlushBaselineCode"),
kFeatureDefaultStateControlledByV8);
// Enables code flushing based on tab visibility.
BASE_FEATURE(kV8FlushCodeBasedOnTabVisibility,
("V8FlushCodeBasedOnTabVisibility"),
kFeatureDefaultStateControlledByV8);
// Enables code flushing based on time.
BASE_FEATURE(kV8FlushCodeBasedOnTime,
("V8FlushCodeBasedOnTime"),
kFeatureDefaultStateControlledByV8);
const base::FeatureParam<int> kV8FlushCodeOldTime{&kV8FlushCodeBasedOnTime,
"V8FlushCodeOldTime", 30};
// Enables finalizing streaming JS compilations on a background thread.
BASE_FEATURE(kV8OffThreadFinalization,
("V8OffThreadFinalization"),
kFeatureDefaultStateControlledByV8);
// Enables lazy feedback allocation in V8.
BASE_FEATURE(kV8LazyFeedbackAllocation,
("V8LazyFeedbackAllocation"),
kFeatureDefaultStateControlledByV8);
// Enables per-context marking worklists in V8 GC.
BASE_FEATURE(kV8PerContextMarkingWorklist,
("V8PerContextMarkingWorklist"),
kFeatureDefaultStateControlledByV8);
// Enables flushing of the instruction cache for the embedded blob.
BASE_FEATURE(kV8FlushEmbeddedBlobICache,
("V8FlushEmbeddedBlobICache"),
kFeatureDefaultStateControlledByV8);
// Enables reduced number of concurrent marking tasks.
BASE_FEATURE(kV8ReduceConcurrentMarkingTasks,
("V8ReduceConcurrentMarkingTasks"),
kFeatureDefaultStateControlledByV8);
// Disables reclaiming of unmodified wrappers objects.
BASE_FEATURE(kV8NoReclaimUnmodifiedWrappers,
("V8NoReclaimUnmodifiedWrappers"),
kFeatureDefaultStateControlledByV8);
// Enables W^X code memory protection in V8.
// This is enabled in V8 by default. To test the performance impact, we are
// going to disable this feature in a finch experiment.
BASE_FEATURE(kV8CodeMemoryWriteProtection,
("V8CodeMemoryWriteProtection"),
kFeatureDefaultStateControlledByV8);
// Enables fallback to a breadth-first regexp engine on excessive backtracking.
BASE_FEATURE(kV8ExperimentalRegexpEngine,
"V8ExperimentalRegexpEngine",
kFeatureDefaultStateControlledByV8);
// Enable accounting for external memory limits as part of global limits in v8
// Heap.
BASE_FEATURE(kV8ExternalMemoryAccountedInGlobalLimit,
"V8ExternalMemoryAccountedInGlobalLimit",
kFeatureDefaultStateControlledByV8);
// Enables the Turbofan compiler.
BASE_FEATURE(kV8Turbofan, ("V8Turbofan"), kFeatureDefaultStateControlledByV8);
// Enables Turbofan's new compiler IR Turboshaft.
BASE_FEATURE(kV8Turboshaft,
("V8Turboshaft"),
kFeatureDefaultStateControlledByV8);
// Enable running instruction selection on Turboshaft IR directly.
BASE_FEATURE(kV8TurboshaftInstructionSelection,
("V8TurboshaftInstructionSelection"),
kFeatureDefaultStateControlledByV8);
// Enables Maglev compiler. Note that this only sets the V8 flag when
// manually overridden; otherwise it defers to whatever the V8 default is.
BASE_FEATURE(kV8Maglev, ("V8Maglev"), kFeatureDefaultStateControlledByV8);
BASE_FEATURE(kV8ConcurrentMaglevHighPriorityThreads,
("V8ConcurrentMaglevHighPriorityThreads"),
kFeatureDefaultStateControlledByV8);
BASE_FEATURE(kV8MemoryReducer,
"V8MemoryReducer",
base::FEATURE_DISABLED_BY_DEFAULT);
const base::FeatureParam<int> kV8MemoryReducerGCCount{
&kV8MemoryReducer, "V8MemoryReducerGCCount", 3};
BASE_FEATURE(kV8PreconfigureOldGen,
"V8PreconfigureOldGen",
kFeatureDefaultStateControlledByV8);
const base::FeatureParam<int> kV8PreconfigureOldGenSize{
&kV8PreconfigureOldGen, "V8PreconfigureOldGenSize", 32};
// Enables MinorMC young generation garbage collector.
BASE_FEATURE(kV8MinorMS, ("V8MinorMS"), kFeatureDefaultStateControlledByV8);
BASE_FEATURE(kV8ScavengerHigherCapacity,
"V8ScavengerHigherCapacity",
base::FEATURE_DISABLED_BY_DEFAULT);
const base::FeatureParam<int> kV8ScavengerMaxCapacity{
&kV8ScavengerHigherCapacity, "V8ScavengerMaxCapacity", 16};
// Enables Sparkplug compiler. Note that this only sets the V8 flag when
// manually overridden; otherwise it defers to whatever the V8 default is.
BASE_FEATURE(kV8Sparkplug, ("V8Sparkplug"), kFeatureDefaultStateControlledByV8);
// Enables the concurrent Sparkplug compiler.
BASE_FEATURE(kV8ConcurrentSparkplug,
("V8ConcurrentSparkplug"),
kFeatureDefaultStateControlledByV8);
const base::FeatureParam<int> kV8ConcurrentSparkplugMaxThreads{
&kV8ConcurrentSparkplug, "V8ConcurrentSparkplugMaxThreads", 0};
BASE_FEATURE(kV8ConcurrentSparkplugHighPriorityThreads,
("V8ConcurrentSparkplugHighPriorityThreads"),
kFeatureDefaultStateControlledByV8);
// Makes sure the experimental Sparkplug compiler is only enabled if short
// builtin calls are enabled too.
BASE_FEATURE(kV8SparkplugNeedsShortBuiltinCalls,
("V8SparkplugNeedsShortBuiltinCalls"),
kFeatureDefaultStateControlledByV8);
// Enables batch compilation for Sparkplug (baseline) compilation.
BASE_FEATURE(kV8BaselineBatchCompilation,
("V8BaselineBatchCompilation"),
kFeatureDefaultStateControlledByV8);
// Enables short builtin calls feature.
BASE_FEATURE(kV8ShortBuiltinCalls,
("V8ShortBuiltinCalls"),
kFeatureDefaultStateControlledByV8);
// Enables fast API calls in TurboFan.
BASE_FEATURE(kV8TurboFastApiCalls,
("V8TurboFastApiCalls"),
kFeatureDefaultStateControlledByV8);
// Enables faster DOM methods for megamorphic ICs
BASE_FEATURE(kV8MegaDomIC, ("V8MegaDomIC"), kFeatureDefaultStateControlledByV8);
// Faster object cloning
BASE_FEATURE(kV8SideStepTransitions,
("V8SideStepTransitions"),
kFeatureDefaultStateControlledByV8);
// Avoids background threads for GC if isolate is in background.
BASE_FEATURE(kV8SingleThreadedGCInBackground,
("V8SingleThreadedGCInBackground"),
kFeatureDefaultStateControlledByV8);
BASE_FEATURE(kV8SingleThreadedGCInBackgroundParallelPause,
("V8SingleThreadedGCInBackgroundParallelPause"),
kFeatureDefaultStateControlledByV8);
BASE_FEATURE(kV8SingleThreadedGCInBackgroundNoIncrementalMarking,
"V8SingleThreadedGCInBackgroundNoIncrementalMarking",
kFeatureDefaultStateControlledByV8);
// Use V8 efficiency mode for tiering decisions.
BASE_FEATURE(kV8EfficiencyModeTiering,
"V8EfficiencyModeTiering",
base::FEATURE_ENABLED_BY_DEFAULT);
const base::FeatureParam<int> kV8EfficiencyModeTieringDelayTurbofan{
&kV8EfficiencyModeTiering, "V8EfficiencyModeTieringDelayTurbofan", 15000};
// Enables slow histograms that provide detailed information at increased
// runtime overheads.
BASE_FEATURE(kV8SlowHistograms,
("V8SlowHistograms"),
kFeatureDefaultStateControlledByV8);
// Multiple finch experiments might use slow-histograms. We introduce
// separate feature flags to circumvent finch limitations.
BASE_FEATURE(kV8SlowHistogramsCodeMemoryWriteProtection,
"V8SlowHistogramsCodeMemoryWriteProtection",
base::FEATURE_DISABLED_BY_DEFAULT);
BASE_FEATURE(kV8SlowHistogramsIntelJCCErratumMitigation,
"V8SlowHistogramsIntelJCCErratumMitigation",
base::FEATURE_DISABLED_BY_DEFAULT);
BASE_FEATURE(kV8SlowHistogramsSparkplug,
"V8SlowHistogramsSparkplug",
base::FEATURE_DISABLED_BY_DEFAULT);
BASE_FEATURE(kV8SlowHistogramsSparkplugAndroid,
"V8SlowHistogramsSparkplugAndroid",
base::FEATURE_DISABLED_BY_DEFAULT);
BASE_FEATURE(kV8SlowHistogramsNoTurbofan,
"V8SlowHistogramsNoTurbofan",
base::FEATURE_DISABLED_BY_DEFAULT);
BASE_FEATURE(kV8DelayMemoryReducer,
"V8DelayMemoryReducer",
base::FEATURE_ENABLED_BY_DEFAULT);
const base::FeatureParam<base::TimeDelta> kV8MemoryReducerStartDelay{
&kV8DelayMemoryReducer, "delay", base::Seconds(30)};
BASE_FEATURE(kV8ConcurrentMarkingHighPriorityThreads,
("V8ConcurrentMarkingHighPriorityThreads"),
kFeatureDefaultStateControlledByV8);
BASE_FEATURE(kV8UseLibmTrigFunctions,
("V8UseLibmTrigFunctions"),
kFeatureDefaultStateControlledByV8);
BASE_FEATURE(kV8UseOriginalMessageForStackTrace,
("V8UseOriginalMessageForStackTrace"),
kFeatureDefaultStateControlledByV8);
BASE_FEATURE(kV8IncrementalMarkingStartUserVisible,
("V8IncrementalMarkingStartUserVisible"),
kFeatureDefaultStateControlledByV8);
BASE_FEATURE(kV8IdleGcOnContextDisposal,
("V8IdleGcOnContextDisposal"),
kFeatureDefaultStateControlledByV8);
// Elide redundant TDZ hole checks in bytecode. This only sets the V8 flag when
// manually overridden.
BASE_FEATURE(kV8IgnitionElideRedundantTdzChecks,
("V8IgnitionElideRedundantTdzChecks"),
kFeatureDefaultStateControlledByV8);
// Add additional alignment for some jumps in generated x64 code, to mitigate
// the performance impact of the Intel JCC erratum (https://crbug.com/v8/14225).
// Currently disabled by default in V8, but adding here temporarily to test
// real-world performance impact via a Finch experiment.
BASE_FEATURE(kV8IntelJCCErratumMitigation,
("V8IntelJCCErratumMitigation"),
kFeatureDefaultStateControlledByV8);
// JavaScript language features.
// Enables the RegExp modifiers proposal.
BASE_FEATURE(kJavaScriptRegExpModifiers,
("JavaScriptRegExpModifiers"),
kFeatureDefaultStateControlledByV8);
// Enables the `with` syntax for the Import Attributes proposal.
BASE_FEATURE(kJavaScriptImportAttributes,
("JavaScriptImportAttributes"),
kFeatureDefaultStateControlledByV8);
// Enables the RegExp duplicate named capture groups proposal.
BASE_FEATURE(kJavaScriptRegExpDuplicateNamedGroups,
("JavaScriptRegExpDuplicateNamedGroups"),
kFeatureDefaultStateControlledByV8);
// Enables the Promise.try proposal.
BASE_FEATURE(kJavaScriptPromiseTry,
("JavaScriptPromiseTry"),
kFeatureDefaultStateControlledByV8);
// WebAssembly features.
// Enable WebAssembly deoptimization support (not user visible), see
// https://crbug.com/42204618.
BASE_FEATURE(kWebAssemblyDeopt,
"WebAssemblyDeopt",
kFeatureDefaultStateControlledByV8);
// Feature for WebAssembly speculative inlining of indirect calls (see
// https://crbug.com/335082212; and https://crbug.com/40898108 for direct call
// and call_ref inlining, which has already launched above). Not user visible.
BASE_FEATURE(kWebAssemblyInliningCallIndirect,
"WebAssemblyInliningCallIndirect",
kFeatureDefaultStateControlledByV8);
} // namespace features
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