Changeset 187351 in webkit for trunk/Source/JavaScriptCore/parser/Parser.h

Timestamp:

Jul 24, 2015, 11:40:58 AM (10 years ago)

Author:

[email protected]

Message:

[ES6] Add support for default parameters
​https://bugs.webkit.org/show_bug.cgi?id=38409

Reviewed by Filip Pizlo.

Source/JavaScriptCore:

This patch implements ES6 default parameters according to the ES6
specification. This patch builds off the components introduced with
"let" scoping and parsing function parameters in the same parser
arena as the function itself. "let" scoping allows functions with default
parameter values to place their parameters under the TDZ. Parsing function
parameters in the same parser arena allows the FunctionParameters AST node
refer to ExpressionNodes.

The most subtle part of this patch is how we allocate lexical environments
when functions have default parameter values. If a function has default
parameter values then there must be a separate lexical environment for
its parameters. Then, the function's "var" lexical environment must have
the parameter lexical environment as its parent. The BytecodeGenerator
takes great care to not allocate the "var" lexical environment before its
really needed.

The "arguments" object for a function with default parameters will never be
a mapped arugments object. It will always be a cloned arugments object.

• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::generate):
(JSC::BytecodeGenerator::BytecodeGenerator):
(JSC::BytecodeGenerator::~BytecodeGenerator):
(JSC::BytecodeGenerator::initializeDefaultParameterValuesAndSetupFunctionScopeStack):
(JSC::BytecodeGenerator::initializeNextParameter):
(JSC::BytecodeGenerator::initializeVarLexicalEnvironment):
(JSC::BytecodeGenerator::visibleNameForParameter):
(JSC::BytecodeGenerator::emitLoadGlobalObject):
(JSC::BytecodeGenerator::pushLexicalScopeInternal):
(JSC::BytecodeGenerator::pushLexicalScope):
(JSC::BytecodeGenerator::popLexicalScope):

• bytecompiler/BytecodeGenerator.h:

(JSC::BytecodeGenerator::lastOpcodeID):

• bytecompiler/NodesCodegen.cpp:

(JSC::FunctionNode::emitBytecode):

• jit/JITOperations.cpp:
• parser/ASTBuilder.h:

(JSC::ASTBuilder::createElementList):
(JSC::ASTBuilder::createFormalParameterList):
(JSC::ASTBuilder::appendParameter):
(JSC::ASTBuilder::createClause):
(JSC::ASTBuilder::createClauseList):

• parser/Nodes.h:

(JSC::FunctionParameters::size):
(JSC::FunctionParameters::at):
(JSC::FunctionParameters::hasDefaultParameterValues):
(JSC::FunctionParameters::append):

• parser/Parser.cpp:

(JSC::Parser<LexerType>::parseVariableDeclarationList):
(JSC::Parser<LexerType>::createBindingPattern):
(JSC::Parser<LexerType>::tryParseDestructuringPatternExpression):
(JSC::Parser<LexerType>::parseDestructuringPattern):
(JSC::Parser<LexerType>::parseFormalParameters):
(JSC::Parser<LexerType>::parseFunctionParameters):

• parser/Parser.h:

(JSC::Scope::declareParameter):

• parser/SyntaxChecker.h:

(JSC::SyntaxChecker::createElementList):
(JSC::SyntaxChecker::createFormalParameterList):
(JSC::SyntaxChecker::appendParameter):
(JSC::SyntaxChecker::createClause):
(JSC::SyntaxChecker::createClauseList):

• tests/stress/es6-default-parameters.js: Added.

(assert):
(shouldThrow):
(shouldThrowSyntaxError):
(shouldThrowTDZ):
(basic):
(basicFunctionCaptureInDefault.basicFunctionCaptureInDefault.basicCaptured):
(basicCaptured.basicCaptured.tricky):
(strict):
(playground):
(scoping):
(augmentsArguments1):
(augmentsArguments2):
(augmentsArguments3):
(augmentsArguments4):
(augmentsArguments5):

LayoutTests:

• js/destructuring-assignment-default-values-expected.txt:
• js/parser-syntax-check-expected.txt:
• js/script-tests/destructuring-assignment-default-values.js:

(shouldThrow): Deleted.

• js/script-tests/parser-syntax-check.js:

File:

• trunk/Source/JavaScriptCore/parser/Parser.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/parser/Parser.h

@@ -353 +353 @@
         if (isArgumentsIdent)
             m_shadowsArguments = true;
+        if (!addResult.isNewEntry)
+            result |= DeclarationResult::InvalidDuplicateDeclaration;
 
         return result;
@@ -1049 +1051 @@
     template <class TreeBuilder> TreeSourceElements parseArrowFunctionSingleExpressionBodySourceElements(TreeBuilder&);
     template <class TreeBuilder> TreeExpression parseArrowFunctionExpression(TreeBuilder&);
-    template <class TreeBuilder> NEVER_INLINE TreeDestructuringPattern createBindingPattern(TreeBuilder&, DestructuringKind, const Identifier&, int depth, JSToken, AssignmentContext);
-    template <class TreeBuilder> NEVER_INLINE TreeDestructuringPattern parseDestructuringPattern(TreeBuilder&, DestructuringKind, AssignmentContext = AssignmentContext::DeclarationStatement, int depth = 0);
+    template <class TreeBuilder> NEVER_INLINE TreeDestructuringPattern createBindingPattern(TreeBuilder&, DestructuringKind, const Identifier&, int depth, JSToken, AssignmentContext, const Identifier** duplicateIdentifier);
+    template <class TreeBuilder> NEVER_INLINE TreeDestructuringPattern parseDestructuringPattern(TreeBuilder&, DestructuringKind, const Identifier** duplicateIdentifier = nullptr, bool* hasDestructuringPattern = nullptr, AssignmentContext = AssignmentContext::DeclarationStatement, int depth = 0);
     template <class TreeBuilder> NEVER_INLINE TreeDestructuringPattern tryParseDestructuringPatternExpression(TreeBuilder&, AssignmentContext);
     template <class TreeBuilder> NEVER_INLINE TreeExpression parseDefaultValueForDestructuringPattern(TreeBuilder&);