Changeset 28973 in webkit for trunk/JavaScriptCore/kjs/nodes2string.cpp

Timestamp:

Dec 24, 2007, 2:13:00 AM (17 years ago)

Author:

[email protected]

Message:

Reviewed by Eric.

• Optimize variable declarations ​http://bugs.webkit.org/show_bug.cgi?id=16585

3.5% speedup on SunSpider.

var statements now result in either assignments or empty statements.

This allows a couple of optimization opportunities:

• No need to branch at runtime to check if there is an initializer
• EmptyStatementNodes can be removed entirely (also done in this patch)
• Assignment expressions get properly optimized for local variables

This patch also includes some code cleanup:

• Most of the old VarStatement/VarDecl logic is now only used for const declarations, thus it is renamed appropriately
• AssignExprNode is gone

• JavaScriptCore.exp:
• kjs/NodeInfo.h:
• kjs/grammar.y:
• kjs/nodes.cpp: (KJS::SourceElements::append): (KJS::ConstDeclNode::ConstDeclNode): (KJS::ConstDeclNode::optimizeVariableAccess): (KJS::ConstDeclNode::handleSlowCase): (KJS::ConstDeclNode::evaluateSingle): (KJS::ConstDeclNode::evaluate): (KJS::ConstStatementNode::optimizeVariableAccess): (KJS::ConstStatementNode::execute): (KJS::VarStatementNode::optimizeVariableAccess): (KJS::VarStatementNode::execute): (KJS::ForInNode::ForInNode): (KJS::ForInNode::optimizeVariableAccess): (KJS::ForInNode::execute): (KJS::FunctionBodyNode::initializeSymbolTable): (KJS::ProgramNode::initializeSymbolTable): (KJS::FunctionBodyNode::processDeclarations): (KJS::ProgramNode::processDeclarations): (KJS::EvalNode::processDeclarations):
• kjs/nodes.h: (KJS::DeclarationStacks::): (KJS::StatementNode::): (KJS::ConstDeclNode::): (KJS::ConstStatementNode::): (KJS::EmptyStatementNode::): (KJS::VarStatementNode::): (KJS::ForNode::):
• kjs/nodes2string.cpp: (KJS::ConstDeclNode::streamTo): (KJS::ConstStatementNode::streamTo): (KJS::ScopeNode::streamTo): (KJS::VarStatementNode::streamTo): (KJS::ForNode::streamTo): (KJS::ForInNode::streamTo):

File:

• trunk/JavaScriptCore/kjs/nodes2string.cpp (modified) (5 diffs)

trunk/JavaScriptCore/kjs/nodes2string.cpp

@@ -708 +708 @@
 }
 
-void AssignExprNode::streamTo(SourceStream& s) const
-{
-    s << " = " << PrecAssignment << expr;
-}
-
-void VarDeclNode::streamTo(SourceStream& s) const
-{
-    s << "var " << ident << init;
-    for (VarDeclNode* n = next.get(); n; n = n->next.get())
-        s << ", " << ident << init;
-}
-
-void VarStatementNode::streamTo(SourceStream& s) const
-{
-    s << Endl << next << ';';
+void ConstDeclNode::streamTo(SourceStream& s) const
+{
+    s << ident;
+    if (init)
+        s << " = " << init;
+    for (ConstDeclNode* n = next.get(); n; n = n->next.get()) {
+        s << ", " << ident;
+        if (init)
+            s << " = " << init;
+    }
+}
+
+void ConstStatementNode::streamTo(SourceStream& s) const
+{
+    s << Endl << "const " << next << ';';
 }
 
@@ -738 +738 @@
 }
 
+void ScopeNode::streamTo(SourceStream& s) const
+{
+    s << Endl << "{" << Indent;
+
+    bool printedVar = false;
+    for (size_t i = 0; i < m_varStack.size(); ++i) {
+        if (m_varStack[i].second == 0) {
+            if (!printedVar) {
+                s << Endl << "var ";
+                printedVar = true;
+            } else
+                s << ", ";
+            s << m_varStack[i].first;
+        }
+    }
+    if (printedVar)
+        s << ';';
+
+    statementListStreamTo(m_children, s); 
+    s << Unindent << Endl << "}";
+}
+
 void EmptyStatementNode::streamTo(SourceStream& s) const
 {
@@ -746 +768 @@
 {
     s << Endl << expr << ';';
+}
+
+void VarStatementNode::streamTo(SourceStream& s) const
+{
+    s << Endl << "var " << expr << ';';
 }
 
@@ -773 +800 @@
 {
     s << Endl << "for ("
+        << (expr1WasVarDecl ? "var " : "")
         << expr1
         << "; " << expr2
@@ -782 +810 @@
 {
     s << Endl << "for (";
-    if (varDecl)
-        s << varDecl;
-    else
+    if (identIsVarDecl) {
+        s << "var ";
+        if (init)
+            s << init;
+        else
+            s << PrecLeftHandSide << lexpr;
+    } else
         s << PrecLeftHandSide << lexpr;