gin/gin_features.cc

   1 // Copyright 2017 The Chromium Authors
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "gin/gin_features.h"
   6 #include "base/metrics/field_trial_params.h"
   7
   8 namespace features {
   9
  10 // Enable code space compaction when finalizing a full GC with stack.
  11 BASE_FEATURE(kV8CompactCodeSpaceWithStack,
  12              "V8CompactCodeSpaceWithStack",
  13              base::FEATURE_ENABLED_BY_DEFAULT);
  14
  15 // Enable compaction when finalizing a full GC with stack.
  16 BASE_FEATURE(kV8CompactWithStack,
  17              "V8CompactWithStack",
  18              base::FEATURE_ENABLED_BY_DEFAULT);
  19
  20 // Enables optimization of JavaScript in V8.
  21 BASE_FEATURE(kV8OptimizeJavascript,
  22              "V8OptimizeJavascript",
  23              base::FEATURE_ENABLED_BY_DEFAULT);
  24
  25 // Enables flushing of JS bytecode in V8.
  26 BASE_FEATURE(kV8FlushBytecode,
  27              "V8FlushBytecode",
  28              base::FEATURE_ENABLED_BY_DEFAULT);
  29 const base::FeatureParam<int> kV8FlushBytecodeOldAge{
  30     &kV8FlushBytecode, "V8FlushBytecodeOldAge", 5};
  31
  32 // Enables flushing of baseline code in V8.
  33 BASE_FEATURE(kV8FlushBaselineCode,
  34              "V8FlushBaselineCode",
  35              base::FEATURE_DISABLED_BY_DEFAULT);
  36
  37 // Enables code flushing based on tab visibility.
  38 BASE_FEATURE(kV8FlushCodeBasedOnTabVisibility,
  39              "V8FlushCodeBasedOnTabVisibility",
  40              base::FEATURE_DISABLED_BY_DEFAULT);
  41
  42 // Enables code flushing based on time.
  43 BASE_FEATURE(kV8FlushCodeBasedOnTime,
  44              "V8FlushCodeBasedOnTime",
  45              base::FEATURE_DISABLED_BY_DEFAULT);
  46 const base::FeatureParam<int> kV8FlushCodeOldTime{&kV8FlushCodeBasedOnTime,
  47                                                   "V8FlushCodeOldTime", 30};
  48
  49 // Enables finalizing streaming JS compilations on a background thread.
  50 BASE_FEATURE(kV8OffThreadFinalization,
  51              "V8OffThreadFinalization",
  52              base::FEATURE_ENABLED_BY_DEFAULT);
  53
  54 // Enables lazy feedback allocation in V8.
  55 BASE_FEATURE(kV8LazyFeedbackAllocation,
  56              "V8LazyFeedbackAllocation",
  57              base::FEATURE_ENABLED_BY_DEFAULT);
  58
  59 // Enables per-context marking worklists in V8 GC.
  60 BASE_FEATURE(kV8PerContextMarkingWorklist,
  61              "V8PerContextMarkingWorklist",
  62              base::FEATURE_DISABLED_BY_DEFAULT);
  63
  64 // Enables flushing of the instruction cache for the embedded blob.
  65 BASE_FEATURE(kV8FlushEmbeddedBlobICache,
  66              "V8FlushEmbeddedBlobICache",
  67              base::FEATURE_DISABLED_BY_DEFAULT);
  68
  69 // Enables reduced number of concurrent marking tasks.
  70 BASE_FEATURE(kV8ReduceConcurrentMarkingTasks,
  71              "V8ReduceConcurrentMarkingTasks",
  72              base::FEATURE_DISABLED_BY_DEFAULT);
  73
  74 // Disables reclaiming of unmodified wrappers objects.
  75 BASE_FEATURE(kV8NoReclaimUnmodifiedWrappers,
  76              "V8NoReclaimUnmodifiedWrappers",
  77              base::FEATURE_DISABLED_BY_DEFAULT);
  78
  79 // Enables W^X code memory protection in V8.
  80 // This is enabled in V8 by default. To test the performance impact, we are
  81 // going to disable this feature in a finch experiment.
  82 BASE_FEATURE(kV8CodeMemoryWriteProtection,
  83              "V8CodeMemoryWriteProtection",
  84              base::FEATURE_ENABLED_BY_DEFAULT);
  85
  86 // Enables fallback to a breadth-first regexp engine on excessive backtracking.
  87 BASE_FEATURE(kV8ExperimentalRegexpEngine,
  88              "V8ExperimentalRegexpEngine",
  89              base::FEATURE_ENABLED_BY_DEFAULT);
  90
  91 // Enables the Turbofan compiler.
  92 BASE_FEATURE(kV8Turbofan, "V8Turbofan", base::FEATURE_ENABLED_BY_DEFAULT);
  93
  94 // Enables Turbofan's new compiler IR Turboshaft.
  95 BASE_FEATURE(kV8Turboshaft, "V8Turboshaft", base::FEATURE_ENABLED_BY_DEFAULT);
  96
  97 // Enable running instruction selection on Turboshaft IR directly.
  98 BASE_FEATURE(kV8TurboshaftInstructionSelection,
  99              "V8TurboshaftInstructionSelection",
 100              base::FEATURE_DISABLED_BY_DEFAULT);
 101
 102 // Enables Maglev compiler. Note that this only sets the V8 flag when
 103 // manually overridden; otherwise it defers to whatever the V8 default is.
 104 BASE_FEATURE(kV8Maglev, "V8Maglev", base::FEATURE_ENABLED_BY_DEFAULT);
 105
 106 BASE_FEATURE(kV8MemoryReducer,
 107              "V8MemoryReducer",
 108              base::FEATURE_DISABLED_BY_DEFAULT);
 109
 110 const base::FeatureParam<int> kV8MemoryReducerGCCount{
 111     &kV8MemoryReducer, "V8MemoryReducerGCCount", 3};
 112
 113 // Enables MinorMC young generation garbage collector.
 114 BASE_FEATURE(kV8MinorMS, "V8MinorMS", base::FEATURE_DISABLED_BY_DEFAULT);
 115
 116 // Enables Sparkplug compiler. Note that this only sets the V8 flag when
 117 // manually overridden; otherwise it defers to whatever the V8 default is.
 118 BASE_FEATURE(kV8Sparkplug, "V8Sparkplug", base::FEATURE_ENABLED_BY_DEFAULT);
 119
 120 // Enables the concurrent Sparkplug compiler.
 121 BASE_FEATURE(kV8ConcurrentSparkplug,
 122              "V8ConcurrentSparkplug",
 123              base::FEATURE_DISABLED_BY_DEFAULT);
 124 const base::FeatureParam<int> kV8ConcurrentSparkplugMaxThreads{
 125     &kV8ConcurrentSparkplug, "V8ConcurrentSparkplugMaxThreads", 0};
 126 BASE_FEATURE(kV8ConcurrentSparkplugHighPriorityThreads,
 127              "V8ConcurrentSparkplugHighPriorityThreads",
 128              base::FEATURE_DISABLED_BY_DEFAULT);
 129 // Makes sure the experimental Sparkplug compiler is only enabled if short
 130 // builtin calls are enabled too.
 131 BASE_FEATURE(kV8SparkplugNeedsShortBuiltinCalls,
 132              "V8SparkplugNeedsShortBuiltinCalls",
 133              base::FEATURE_DISABLED_BY_DEFAULT);
 134
 135 // Enables short builtin calls feature.
 136 BASE_FEATURE(kV8ShortBuiltinCalls,
 137              "V8ShortBuiltinCalls",
 138              base::FEATURE_ENABLED_BY_DEFAULT);
 139
 140 // Enables fast API calls in TurboFan.
 141 BASE_FEATURE(kV8TurboFastApiCalls,
 142              "V8TurboFastApiCalls",
 143              base::FEATURE_ENABLED_BY_DEFAULT);
 144
 145 // Enables faster DOM methods for megamorphic ICs
 146 BASE_FEATURE(kV8MegaDomIC, "V8MegaDomIC", base::FEATURE_DISABLED_BY_DEFAULT);
 147
 148 // Avoids background threads for GC if isolate is in background.
 149 BASE_FEATURE(kV8SingleThreadedGCInBackground,
 150              "V8SingleThreadedGCInBackground",
 151              base::FEATURE_DISABLED_BY_DEFAULT);
 152
 153 // Enables slow histograms that provide detailed information at increased
 154 // runtime overheads.
 155 BASE_FEATURE(kV8SlowHistograms,
 156              "V8SlowHistograms",
 157              base::FEATURE_DISABLED_BY_DEFAULT);
 158 // Multiple finch experiments might use slow-histograms. We introduce
 159 // separate feature flags to circumvent finch limitations.
 160 BASE_FEATURE(kV8SlowHistogramsCodeMemoryWriteProtection,
 161              "V8SlowHistogramsCodeMemoryWriteProtection",
 162              base::FEATURE_DISABLED_BY_DEFAULT);
 163 BASE_FEATURE(kV8SlowHistogramsSparkplug,
 164              "V8SlowHistogramsSparkplug",
 165              base::FEATURE_DISABLED_BY_DEFAULT);
 166 BASE_FEATURE(kV8SlowHistogramsSparkplugAndroid,
 167              "V8SlowHistogramsSparkplugAndroid",
 168              base::FEATURE_DISABLED_BY_DEFAULT);
 169 BASE_FEATURE(kV8SlowHistogramsNoTurbofan,
 170              "V8SlowHistogramsNoTurbofan",
 171              base::FEATURE_DISABLED_BY_DEFAULT);
 172
 173 BASE_FEATURE(kV8DelayMemoryReducer,
 174              "V8DelayMemoryReducer",
 175              base::FEATURE_ENABLED_BY_DEFAULT);
 176 const base::FeatureParam<base::TimeDelta> kV8MemoryReducerStartDelay{
 177     &kV8DelayMemoryReducer, "delay", base::Seconds(30)};
 178
 179 BASE_FEATURE(kV8ConcurrentMarkingHighPriorityThreads,
 180              "V8ConcurrentMarkingHighPriorityThreads",
 181              base::FEATURE_DISABLED_BY_DEFAULT);
 182
 183 BASE_FEATURE(kV8UseLibmTrigFunctions,
 184              "V8UseLibmTrigFunctions",
 185              base::FEATURE_ENABLED_BY_DEFAULT);
 186
 187 // Elide redundant TDZ hole checks in bytecode. This only sets the V8 flag when
 188 // manually overridden.
 189 BASE_FEATURE(kV8IgnitionElideRedundantTdzChecks,
 190              "V8IgnitionElideRedundantTdzChecks",
 191              base::FEATURE_ENABLED_BY_DEFAULT);
 192
 193 // The currently enabled fallback to the mid-tier register allocator for huge
 194 // Wasm functions. We want to remove this fallback in the future.
 195 BASE_FEATURE(kV8MidtierRegallocFallback,
 196              "V8MidtierRegallocFallback",
 197              base::FEATURE_DISABLED_BY_DEFAULT);
 198
 199 // JavaScript language features.
 200
 201 // Enables the Symbols-as-WeakMap-keys proposal.
 202 BASE_FEATURE(kJavaScriptSymbolAsWeakMapKey,
 203              "JavaScriptSymbolAsWeakMapKey",
 204              base::FEATURE_ENABLED_BY_DEFAULT);
 205
 206 // Enables the change-Array-by-copy proposal.
 207 BASE_FEATURE(kJavaScriptChangeArrayByCopy,
 208              "JavaScriptChangeArrayByCopy",
 209              base::FEATURE_ENABLED_BY_DEFAULT);
 210
 211 // Enables the Resizable ArrayBuffer proposal.
 212 BASE_FEATURE(kJavaScriptRabGsab,
 213              "JavaScriptRabGsab",
 214              base::FEATURE_ENABLED_BY_DEFAULT);
 215
 216 // Enables the JavaScript RegExp Unicode set notation proposal.
 217 BASE_FEATURE(kJavaScriptRegExpUnicodeSets,
 218              "JavaScriptRegExpUnicodeSets",
 219              base::FEATURE_ENABLED_BY_DEFAULT);
 220
 221 // Enables the JSON.parse with source proposal.
 222 BASE_FEATURE(kJavaScriptJsonParseWithSource,
 223              "JavaScriptJsonParseWithSource",
 224              base::FEATURE_ENABLED_BY_DEFAULT);
 225
 226 // Enables the ArrayBuffer transfer proposal.
 227 BASE_FEATURE(kJavaScriptArrayBufferTransfer,
 228              "JavaScriptArrayBufferTransfer",
 229              base::FEATURE_ENABLED_BY_DEFAULT);
 230
 231 // Enables the experiment with compile hints as magic comments.
 232 BASE_FEATURE(kJavaScriptCompileHintsMagic,
 233              "JavaScriptCompileHintsMagic",
 234              base::FEATURE_DISABLED_BY_DEFAULT);
 235
 236 // Enables the iterator helpers proposal.
 237 BASE_FEATURE(kJavaScriptIteratorHelpers,
 238              "kJavaScriptIteratorHelpers",
 239              base::FEATURE_ENABLED_BY_DEFAULT);
 240
 241 // Enables the Promise.withResolvers proposal.
 242 BASE_FEATURE(kJavaScriptPromiseWithResolvers,
 243              "JavaScriptPromiseWithResolvers",
 244              base::FEATURE_ENABLED_BY_DEFAULT);
 245
 246 // WebAssembly features.
 247
 248 // Enable support for the WebAssembly tail-call proposal:
 249 // https://github.com/WebAssembly/tail-call.
 250 BASE_FEATURE(kWebAssemblyTailCall,
 251              "WebAssemblyTailCall",
 252              base::FEATURE_ENABLED_BY_DEFAULT);
 253
 254 // Enable WebAssembly inlining (not user visible).
 255 BASE_FEATURE(kWebAssemblyInlining,
 256              "WebAssemblyInlining",
 257              base::FEATURE_DISABLED_BY_DEFAULT);
 258
 259 // Enable the generic wasm-to-js wrapper.
 260 BASE_FEATURE(kWebAssemblyGenericWrapper,
 261              "WebAssemblyGenericWrapper",
 262              base::FEATURE_DISABLED_BY_DEFAULT);
 263
 264 // Enable support for multiple memories according to the multi-memory proposal:
 265 // https://github.com/WebAssembly/multi-memory. See
 266 // https://chromestatus.com/feature/5106389887746048.
 267 BASE_FEATURE(kWebAssemblyMultipleMemories,
 268              "WebAssemblyMultipleMemories",
 269              base::FEATURE_ENABLED_BY_DEFAULT);
 270
 271 BASE_FEATURE(kWebAssemblyTurboshaft,
 272              "WebAssemblyTurboshaft",
 273              base::FEATURE_DISABLED_BY_DEFAULT);
 274
 275 }  // namespace features