Changeset 191110 in webkit for trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

Timestamp:

Oct 15, 2015, 7:35:12 AM (10 years ago)

Author:

Yusuke Suzuki

Message:

[ES6] Class expression should have lexical environment that has itself as an imutable binding
​https://bugs.webkit.org/show_bug.cgi?id=150089

Reviewed by Geoffrey Garen.

According to ES6 spec, class expression has its own lexical environment that holds itself
as an immutable binding[1] (section 14.5.14 step 2, 3, 4, 23)

As a result, even if the binding declared in the outer scope is overridden, methods inside
class expression can refer its class by the class name.

[1]: ​http://ecma-international.org/ecma-262/6.0/#sec-runtime-semantics-classdefinitionevaluation

• bytecompiler/NodesCodegen.cpp:

(JSC::ClassExprNode::emitBytecode):

• parser/ASTBuilder.h:

(JSC::ASTBuilder::createClassExpr):

• parser/NodeConstructors.h:

(JSC::ClassExprNode::ClassExprNode):

• parser/Nodes.h:
• parser/Parser.cpp:

(JSC::Parser<LexerType>::parseClass):

• parser/SyntaxChecker.h:

(JSC::SyntaxChecker::createClassExpr):

• tests/es6.yaml:
• tests/stress/class-expression-generates-environment.js: Added.

(shouldBe):
(shouldThrow):
(prototype.method):
(staticMethod):
(A.prototype.method):
(A.staticMethod):
(A):

• tests/stress/class-expression-should-be-tdz-in-heritage.js: Added.

(shouldThrow):
(shouldThrow.A):

File:

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

trunk/Source/JavaScriptCore/bytecompiler/NodesCodegen.cpp

@@ -3011 +3011 @@
 RegisterID* ClassExprNode::emitBytecode(BytecodeGenerator& generator, RegisterID* dst)
 {
+    if (!m_name.isNull())
+        generator.pushLexicalScope(this, true);
+
     RefPtr<RegisterID> superclass;
     if (m_classHeritage) {
@@ -3074 +3077 @@
     if (m_instanceMethods)
         generator.emitNode(prototype.get(), m_instanceMethods);
+
+    if (!m_name.isNull()) {
+        Variable classNameVar = generator.variable(m_name);
+        RELEASE_ASSERT(classNameVar.isResolved());
+        RefPtr<RegisterID> scope = generator.emitResolveScope(nullptr, classNameVar);
+        generator.emitPutToScope(scope.get(), classNameVar, constructor.get(), ThrowIfNotFound, Initialization);
+        generator.popLexicalScope(this);
+    }
 
     return generator.moveToDestinationIfNeeded(dst, constructor.get());