Changeset 197410 in webkit for trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

Timestamp:

Mar 1, 2016, 1:28:45 PM (9 years ago)

Author:

[email protected]

Message:

[ES6] Arrow function. Some not used byte code is emited
​https://bugs.webkit.org/show_bug.cgi?id=154639

Reviewed by Saam Barati.

Currently bytecode that is generated for arrow function is not optimal.
Current fix removed following unnecessary bytecode:
1.create_lexical_environment not emited always for arrow function, only if some of
features(this/super/arguments/eval) is used inside of the arrow function.
2.load 'this' from arrow function scope in constructor is done only if super
contains in arrow function

• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::BytecodeGenerator):
(JSC::BytecodeGenerator::isSuperCallUsedInInnerArrowFunction):

• bytecompiler/BytecodeGenerator.h:
• bytecompiler/NodesCodegen.cpp:

(JSC::ThisNode::emitBytecode):
(JSC::FunctionNode::emitBytecode):

• parser/Nodes.h:

(JSC::ScopeNode::doAnyInnerArrowFunctionsUseAnyFeature):

• tests/stress/arrowfunction-lexical-bind-supercall-4.js:

File:

• trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

@@ -147 +147 @@
 RegisterID* ThisNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
-    if (generator.constructorKind() == ConstructorKind::Derived && generator.needsToUpdateArrowFunctionContext() && generator.isThisUsedInInnerArrowFunction())
+    if (generator.constructorKind() == ConstructorKind::Derived && generator.needsToUpdateArrowFunctionContext() && generator.isSuperCallUsedInInnerArrowFunction())
         generator.emitLoadThisFromArrowFunctionLexicalEnvironment();
 
@@ -3139 +3139 @@
         // If there is no return we must automatically insert one.
         if (!returnNode) {
-            if (generator.constructorKind() == ConstructorKind::Derived && generator.needsToUpdateArrowFunctionContext() && generator.isThisUsedInInnerArrowFunction())
+            if (generator.constructorKind() == ConstructorKind::Derived && generator.needsToUpdateArrowFunctionContext() && generator.isSuperCallUsedInInnerArrowFunction())
                 generator.emitLoadThisFromArrowFunctionLexicalEnvironment(); // Arrow function can invoke 'super' in constructor and before leave constructor we need load 'this' from lexical arrow function environment