Changeset 153763 in webkit for trunk/Source/JavaScriptCore/parser/ParserModes.h

Timestamp:

Aug 6, 2013, 2:20:10 PM (12 years ago)

Author:

[email protected]

Message:

Delay Arguments creation in strict mode
​https://bugs.webkit.org/show_bug.cgi?id=119505

Reviewed by Geoffrey Garen.

Source/JavaScriptCore:

Make use of the write tracking performed by the parser to
allow us to know if we're modifying the parameters to a function.
Then use that information to make strict mode function opt out
of eager arguments creation.

• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::BytecodeGenerator):
(JSC::BytecodeGenerator::createArgumentsIfNecessary):
(JSC::BytecodeGenerator::emitReturn):

• bytecompiler/BytecodeGenerator.h:

(JSC::BytecodeGenerator::shouldTearOffArgumentsEagerly):

• parser/Nodes.h:

(JSC::ScopeNode::modifiesParameter):

• parser/Parser.cpp:

(JSC::::parseInner):

• parser/Parser.h:

(JSC::Scope::declareParameter):
(JSC::Scope::getCapturedVariables):
(JSC::Parser::declareWrite):

• parser/ParserModes.h:

LayoutTests:

Add performance testcase for lazy creation of arguments in strict mode

• fast/js/regress/delay-tear-off-arguments-strictmode-expected.txt: Added.
• fast/js/regress/delay-tear-off-arguments-strictmode.html: Added.
• fast/js/regress/script-tests/delay-tear-off-arguments-strictmode.js: Added.

(bar):

File:

• trunk/Source/JavaScriptCore/parser/ParserModes.h (modified) (1 diff)

trunk/Source/JavaScriptCore/parser/ParserModes.h

@@ -48 +48 @@
 const CodeFeatures StrictModeFeature = 1 << 5;
 const CodeFeatures ShadowsArgumentsFeature = 1 << 6;
+const CodeFeatures ModifiedParameterFeature = 1 << 7;
 
-const CodeFeatures AllFeatures = EvalFeature | ArgumentsFeature | WithFeature | CatchFeature | ThisFeature | StrictModeFeature | ShadowsArgumentsFeature;
+const CodeFeatures AllFeatures = EvalFeature | ArgumentsFeature | WithFeature | CatchFeature | ThisFeature | StrictModeFeature | ShadowsArgumentsFeature | ModifiedParameterFeature;
 
 } // namespace JSC