Changeset 174606 in webkit for trunk/Source/JavaScriptCore/parser

Timestamp:

Oct 10, 2014, 12:03:20 PM (11 years ago)

Author:

[email protected]

Message:

Various arguments optimisations in codegen fail to account for arguments being in lexical record
​https://bugs.webkit.org/show_bug.cgi?id=137617

Reviewed by Michael Saboff.

Rework the way we track |arguments| references so that we don't try
to use the |arguments| reference on the stack if it's not safe.

To do this without nuking performance it was necessary to update
the parser to track modification of the |arguments| reference
itself.

• bytecode/CodeBlock.cpp:
• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::BytecodeGenerator):
(JSC::BytecodeGenerator::willResolveToArguments):
(JSC::BytecodeGenerator::uncheckedLocalArgumentsRegister):
(JSC::BytecodeGenerator::emitCall):
(JSC::BytecodeGenerator::emitConstruct):
(JSC::BytecodeGenerator::emitEnumeration):
(JSC::BytecodeGenerator::uncheckedRegisterForArguments): Deleted.

• bytecompiler/BytecodeGenerator.h:

(JSC::BytecodeGenerator::hasSafeLocalArgumentsRegister):

• bytecompiler/NodesCodegen.cpp:

(JSC::BracketAccessorNode::emitBytecode):
(JSC::DotAccessorNode::emitBytecode):
(JSC::getArgumentByVal):
(JSC::CallFunctionCallDotNode::emitBytecode):
(JSC::ApplyFunctionCallDotNode::emitBytecode):
(JSC::ArrayPatternNode::emitDirectBinding):

• interpreter/StackVisitor.cpp:

(JSC::StackVisitor::Frame::existingArguments):

• parser/Nodes.h:

(JSC::ScopeNode::modifiesArguments):

• parser/Parser.cpp:

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

• parser/Parser.h:

(JSC::Scope::getCapturedVariables):

• parser/ParserModes.h:

Location:

trunk/Source/JavaScriptCore/parser

Files:

• Nodes.h (modified) (1 diff)
• Parser.cpp (modified) (3 diffs)
• Parser.h (modified) (2 diffs)
• ParserModes.h (modified) (1 diff)

trunk/Source/JavaScriptCore/parser/Nodes.h

@@ -1441 +1441 @@
         bool usesArguments() const { return (m_features & ArgumentsFeature) && !(m_features & ShadowsArgumentsFeature); }
         bool modifiesParameter() const { return m_features & ModifiedParameterFeature; }
+        bool modifiesArguments() const { return m_features & (EvalFeature | ModifiedArgumentsFeature); }
         bool isStrictMode() const { return m_features & StrictModeFeature; }
         void setUsesArguments() { m_features |= ArgumentsFeature; }

trunk/Source/JavaScriptCore/parser/Parser.cpp

@@ -272 +272 @@
     IdentifierSet capturedVariables;
     bool modifiedParameter = false;
-    scope->getCapturedVariables(capturedVariables, modifiedParameter);
+    bool modifiedArguments = false;
+    scope->getCapturedVariables(capturedVariables, modifiedParameter, modifiedArguments);
     
     CodeFeatures features = context.features();
@@ -281 +282 @@
     if (modifiedParameter)
         features |= ModifiedParameterFeature;
-    
+    if (modifiedArguments)
+        features |= ModifiedArgumentsFeature;
     Vector<RefPtr<StringImpl>> closedVariables;
     if (m_parsingBuiltin) {
@@ -293 +295 @@
             if (scope->hasDeclaredParameter(Identifier(m_vm, variable.get())))
                 continue;
+
+            if (variable == m_vm->propertyNames->arguments.impl())
+                continue;
+
             closedVariables.append(variable);
         }

trunk/Source/JavaScriptCore/parser/Parser.h

@@ -280 +280 @@
     }
 
-    void getCapturedVariables(IdentifierSet& capturedVariables, bool& modifiedParameter)
+    void getCapturedVariables(IdentifierSet& capturedVariables, bool& modifiedParameter, bool& modifiedArguments)
     {
         if (m_needsFullActivation || m_usesEval) {
@@ -293 +293 @@
         }
         modifiedParameter = false;
+        if (shadowsArguments())
+            modifiedArguments = true;
         if (m_declaredParameters.size()) {
             IdentifierSet::iterator end = m_writtenVariables.end();
             for (IdentifierSet::iterator ptr = m_writtenVariables.begin(); ptr != end; ++ptr) {
+                if (*ptr == m_vm->propertyNames->arguments.impl())
+                    modifiedArguments = true;
                 if (!m_declaredParameters.contains(*ptr))
                     continue;

trunk/Source/JavaScriptCore/parser/ParserModes.h

@@ -76 +76 @@
 const CodeFeatures ShadowsArgumentsFeature = 1 << 6;
 const CodeFeatures ModifiedParameterFeature = 1 << 7;
+const CodeFeatures ModifiedArgumentsFeature = 1 << 8;
 
 const CodeFeatures AllFeatures = EvalFeature | ArgumentsFeature | WithFeature | CatchFeature | ThisFeature | StrictModeFeature | ShadowsArgumentsFeature | ModifiedParameterFeature;