Changeset 197915 in webkit for trunk/Source/JavaScriptCore/parser/Nodes.cpp

Timestamp:

Mar 9, 2016, 6:04:20 PM (9 years ago)

Author:

[email protected]

Message:

ES6: Implement lexical scoping for function definitions in strict mode
​https://bugs.webkit.org/show_bug.cgi?id=152844

Reviewed by Geoffrey Garen.

Source/JavaScriptCore:

This patch implements block scoping for function definitions
in strict mode. The implementation works as follows:

• If we're in sloppy mode, function declarations work exactly as they did before this patch. I.e, function declarations are hoisted and declared like "var" variables.

• If you're in strict mode and at the top of a function scope or program scope, function declarations still work like they used to. They are defined like "var" variables. This is necessary for backwards compatibility because ES5 strict mode allowed duplicate function declarations at the top-most scope of a program/function.

• If you're in strict mode and inside a block statement or a switch statement, function declarations are now block scoped. All function declarations within a block are hoisted to the beginning of the block. They are not hoisted out of the block like they are in sloppy mode. This allows for the following types of programs: ` function foo() {

function bar() { return 20; }
{

function bar() { return 30; }
bar(); 30

}
bar(); 20

}
`

• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::BytecodeGenerator):
(JSC::BytecodeGenerator::instantiateLexicalVariables):
(JSC::BytecodeGenerator::emitPrefillStackTDZVariables):
(JSC::BytecodeGenerator::pushLexicalScope):
(JSC::BytecodeGenerator::pushLexicalScopeInternal):
(JSC::BytecodeGenerator::initializeBlockScopedFunctions):
(JSC::BytecodeGenerator::popLexicalScope):
(JSC::BytecodeGenerator::liftTDZCheckIfPossible):
(JSC::BytecodeGenerator::pushTDZVariables):
(JSC::BytecodeGenerator::getVariablesUnderTDZ):
(JSC::BytecodeGenerator::emitNewRegExp):
(JSC::BytecodeGenerator::emitNewFunctionExpressionCommon):
(JSC::BytecodeGenerator::emitNewFunctionExpression):
(JSC::BytecodeGenerator::emitNewArrowFunctionExpression):

• bytecompiler/BytecodeGenerator.h:
• parser/ASTBuilder.h:

(JSC::ASTBuilder::createSourceElements):
(JSC::ASTBuilder::features):
(JSC::ASTBuilder::numConstants):
(JSC::ASTBuilder::createFuncDeclStatement):
(JSC::ASTBuilder::createClassDeclStatement):
(JSC::ASTBuilder::createBlockStatement):
(JSC::ASTBuilder::createTryStatement):
(JSC::ASTBuilder::createSwitchStatement):
(JSC::ASTBuilder::Scope::Scope):
(JSC::ASTBuilder::funcDeclarations): Deleted.

• parser/NodeConstructors.h:

(JSC::CaseBlockNode::CaseBlockNode):
(JSC::SwitchNode::SwitchNode):
(JSC::BlockNode::BlockNode):

• parser/Nodes.cpp:

(JSC::ScopeNode::ScopeNode):
(JSC::ScopeNode::singleStatement):
(JSC::ProgramNode::ProgramNode):
(JSC::ModuleProgramNode::ModuleProgramNode):
(JSC::EvalNode::EvalNode):
(JSC::FunctionNode::FunctionNode):
(JSC::VariableEnvironmentNode::VariableEnvironmentNode):

• parser/Nodes.h:

(JSC::VariableEnvironmentNode::VariableEnvironmentNode):
(JSC::VariableEnvironmentNode::lexicalVariables):
(JSC::VariableEnvironmentNode::functionStack):
(JSC::ScopeNode::captures):
(JSC::ScopeNode::varDeclarations):
(JSC::ScopeNode::neededConstants):
(JSC::ProgramNode::startColumn):
(JSC::ProgramNode::endColumn):
(JSC::EvalNode::startColumn):
(JSC::EvalNode::endColumn):
(JSC::ModuleProgramNode::startColumn):
(JSC::ModuleProgramNode::endColumn):
(JSC::ScopeNode::functionStack): Deleted.

• parser/Parser.cpp:

(JSC::Parser<LexerType>::parseInner):
(JSC::Parser<LexerType>::didFinishParsing):
(JSC::Parser<LexerType>::parseStatementListItem):
(JSC::Parser<LexerType>::parseSwitchStatement):
(JSC::Parser<LexerType>::parseBlockStatement):
(JSC::Parser<LexerType>::parseStatement):
(JSC::Parser<LexerType>::parseFunctionInfo):
(JSC::getMetadata):
(JSC::Parser<LexerType>::parseFunctionDeclaration):
(JSC::Parser<LexerType>::parseExportDeclaration):

• parser/Parser.h:

(JSC::Scope::declareVariable):
(JSC::Scope::declareFunction):
(JSC::Scope::appendFunction):
(JSC::Scope::takeFunctionDeclarations):
(JSC::Scope::declareLexicalVariable):
(JSC::Parser::currentVariableScope):
(JSC::Parser::currentLexicalDeclarationScope):
(JSC::Parser::currentFunctionScope):
(JSC::Parser::pushScope):
(JSC::Parser::popScopeInternal):
(JSC::Parser::declareVariable):
(JSC::Parser::declareFunction):
(JSC::Parser::hasDeclaredVariable):
(JSC::Parser::isFunctionMetadataNode):
(JSC::Parser<LexerType>::parse):

• parser/SyntaxChecker.h:

(JSC::SyntaxChecker::createFuncDeclStatement):
(JSC::SyntaxChecker::createClassDeclStatement):
(JSC::SyntaxChecker::createBlockStatement):
(JSC::SyntaxChecker::createExprStatement):
(JSC::SyntaxChecker::createIfStatement):
(JSC::SyntaxChecker::createContinueStatement):
(JSC::SyntaxChecker::createTryStatement):
(JSC::SyntaxChecker::createSwitchStatement):
(JSC::SyntaxChecker::createWhileStatement):
(JSC::SyntaxChecker::createWithStatement):
(JSC::SyntaxChecker::createDoWhileStatement):

• parser/VariableEnvironment.h:

(JSC::VariableEnvironmentEntry::isExported):
(JSC::VariableEnvironmentEntry::isImported):
(JSC::VariableEnvironmentEntry::isImportedNamespace):
(JSC::VariableEnvironmentEntry::isFunction):
(JSC::VariableEnvironmentEntry::setIsCaptured):
(JSC::VariableEnvironmentEntry::setIsConst):
(JSC::VariableEnvironmentEntry::setIsExported):
(JSC::VariableEnvironmentEntry::setIsImported):
(JSC::VariableEnvironmentEntry::setIsImportedNamespace):
(JSC::VariableEnvironmentEntry::setIsFunction):
(JSC::VariableEnvironmentEntry::clearIsVar):
(JSC::VariableEnvironment::VariableEnvironment):
(JSC::VariableEnvironment::begin):
(JSC::VariableEnvironment::end):

• tests/es6.yaml:
• tests/stress/block-scoped-function-declarations.js: Added.

(assert):
(test):
(f.foo.bar):
(f.foo.):
(f.foo):
(f):
(assert.foo.):
(assert.foo):
(assert.foo.foo):
(assert.foo.bar):
(assert.foo.switch.case.1):
(assert.foo.switch.case.2):
(assert.foo.switch.foo):
(assert.foo.switch.bar):

LayoutTests:

• js/let-syntax-expected.txt:
• js/parser-syntax-check-expected.txt:
• js/script-tests/parser-syntax-check.js:

(testFailed):
(runTest):

File:

• trunk/Source/JavaScriptCore/parser/Nodes.cpp (modified) (7 diffs)

trunk/Source/JavaScriptCore/parser/Nodes.cpp

@@ -95 +95 @@
 }
 
-ScopeNode::ScopeNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, const SourceCode& source, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack& funcStack, VariableEnvironment& lexicalVariables, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
+ScopeNode::ScopeNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, const SourceCode& source, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack&& funcStack, VariableEnvironment& lexicalVariables, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
     : StatementNode(endLocation)
     , ParserArenaRoot(parserArena)
-    , VariableEnvironmentNode(lexicalVariables)
+    , VariableEnvironmentNode(lexicalVariables, WTFMove(funcStack))
     , m_startLineNumber(startLocation.line)
     , m_startStartOffset(startLocation.startOffset)
@@ -109 +109 @@
 {
     m_varDeclarations.swap(varEnvironment);
-    m_functionStack.swap(funcStack);
 }
 
@@ -119 +118 @@
 // ------------------------------ ProgramNode -----------------------------
 
-ProgramNode::ProgramNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, unsigned startColumn, unsigned endColumn, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack& funcStack, VariableEnvironment& lexicalVariables, FunctionParameters*, const SourceCode& source, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
-    : ScopeNode(parserArena, startLocation, endLocation, source, children, varEnvironment, funcStack, lexicalVariables, features, innerArrowFunctionCodeFeatures, numConstants)
+ProgramNode::ProgramNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, unsigned startColumn, unsigned endColumn, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack&& funcStack, VariableEnvironment& lexicalVariables, FunctionParameters*, const SourceCode& source, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
+    : ScopeNode(parserArena, startLocation, endLocation, source, children, varEnvironment, WTFMove(funcStack), lexicalVariables, features, innerArrowFunctionCodeFeatures, numConstants)
     , m_startColumn(startColumn)
     , m_endColumn(endColumn)
@@ -128 +127 @@
 // ------------------------------ ModuleProgramNode -----------------------------
 
-ModuleProgramNode::ModuleProgramNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, unsigned startColumn, unsigned endColumn, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack& funcStack, VariableEnvironment& lexicalVariables, FunctionParameters*, const SourceCode& source, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
-    : ScopeNode(parserArena, startLocation, endLocation, source, children, varEnvironment, funcStack, lexicalVariables, features, innerArrowFunctionCodeFeatures, numConstants)
+ModuleProgramNode::ModuleProgramNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, unsigned startColumn, unsigned endColumn, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack&& funcStack, VariableEnvironment& lexicalVariables, FunctionParameters*, const SourceCode& source, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
+    : ScopeNode(parserArena, startLocation, endLocation, source, children, varEnvironment, WTFMove(funcStack), lexicalVariables, features, innerArrowFunctionCodeFeatures, numConstants)
     , m_startColumn(startColumn)
     , m_endColumn(endColumn)
@@ -137 +136 @@
 // ------------------------------ EvalNode -----------------------------
 
-EvalNode::EvalNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, unsigned, unsigned endColumn, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack& funcStack, VariableEnvironment& lexicalVariables, FunctionParameters*, const SourceCode& source, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
-    : ScopeNode(parserArena, startLocation, endLocation, source, children, varEnvironment, funcStack, lexicalVariables, features, innerArrowFunctionCodeFeatures, numConstants)
+EvalNode::EvalNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, unsigned, unsigned endColumn, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack&& funcStack, VariableEnvironment& lexicalVariables, FunctionParameters*, const SourceCode& source, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
+    : ScopeNode(parserArena, startLocation, endLocation, source, children, varEnvironment, WTFMove(funcStack), lexicalVariables, features, innerArrowFunctionCodeFeatures, numConstants)
     , m_endColumn(endColumn)
 {
@@ -183 +182 @@
 // ------------------------------ FunctionNode -----------------------------
 
-FunctionNode::FunctionNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, unsigned startColumn, unsigned endColumn, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack& funcStack, VariableEnvironment& lexicalVariables, FunctionParameters* parameters, const SourceCode& sourceCode, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
-    : ScopeNode(parserArena, startLocation, endLocation, sourceCode, children, varEnvironment, funcStack, lexicalVariables, features, innerArrowFunctionCodeFeatures, numConstants)
+FunctionNode::FunctionNode(ParserArena& parserArena, const JSTokenLocation& startLocation, const JSTokenLocation& endLocation, unsigned startColumn, unsigned endColumn, SourceElements* children, VariableEnvironment& varEnvironment, FunctionStack&& funcStack, VariableEnvironment& lexicalVariables, FunctionParameters* parameters, const SourceCode& sourceCode, CodeFeatures features, InnerArrowFunctionCodeFeatures innerArrowFunctionCodeFeatures, int numConstants)
+    : ScopeNode(parserArena, startLocation, endLocation, sourceCode, children, varEnvironment, WTFMove(funcStack), lexicalVariables, features, innerArrowFunctionCodeFeatures, numConstants)
     , m_parameters(parameters)
     , m_startColumn(startColumn)
@@ -203 +202 @@
 }
 
+VariableEnvironmentNode::VariableEnvironmentNode(VariableEnvironment& lexicalVariables, FunctionStack&& functionStack)
+{
+    m_lexicalVariables.swap(lexicalVariables);
+    m_functionStack = WTFMove(functionStack);
+}
+
 } // namespace JSC