Changeset 27799 in webkit for trunk/JavaScriptCore/kjs/nodes.cpp

Timestamp:

Nov 14, 2007, 2:59:29 PM (18 years ago)

Author:

[email protected]

Message:

Reviewed by Eric Seidel.

Cleaned up the JavaScript grammar a bit.

1. Changed BlockNode to always hold a child vector (which may be empty), eliminating a few NULL-check branches in the common execution case.

2. Changed the Block production to correctly report its starting and ending line numbers to the debugger. (It used to report its ending line as its starting line.) Also, removed duplicate line-reporting code inside the BlockNode constructor.

3. Moved curly braces up from FunctionBody production into parent productions. (I had to move the line number reporting code, too, since it depends on the location of the curly braces.) This matches the ECMA spec more closely, and makes some future changes I plan easier.

4. Fixed statementList* convenience functions to deal appropriately with empty Vectors.

SunSpider reports a small and statistically insignificant speedup.

• kjs/grammar.y:
• kjs/nodes.cpp: (KJS::statementListPushFIFO): (KJS::statementListGetDeclarations): (KJS::statementListInitializeDeclarationStack): (KJS::statementListInitializeVariableAccessStack): (KJS::BlockNode::BlockNode): (KJS::BlockNode::optimizeVariableAccess): (KJS::BlockNode::getDeclarations): (KJS::BlockNode::execute): (KJS::FunctionBodyNode::initializeDeclarationStacks): (KJS::FunctionBodyNode::optimizeVariableAccess):

File:

• trunk/JavaScriptCore/kjs/nodes.cpp (modified) (6 diffs)

trunk/JavaScriptCore/kjs/nodes.cpp

@@ -3597 +3597 @@
 static inline void statementListPushFIFO(SourceElements& statements, DeclarationStacks::NodeStack& stack)
 {
-    for (SourceElements::iterator ptr = statements.end() - 1; ptr >= statements.begin(); --ptr)
-        stack.append((*ptr).get());
+    SourceElements::iterator it = statements.end();
+    SourceElements::iterator begin = statements.begin();
+    while (it != begin) {
+        --it;
+        stack.append((*it).get());
+    }
 }
 
 static inline void statementListGetDeclarations(SourceElements& statements, DeclarationStacks& stacks)
 {
-    for (SourceElements::iterator ptr = statements.end() - 1; ptr >= statements.begin(); --ptr)
-        if ((*ptr)->mayHaveDeclarations())
-            stacks.nodeStack.append((*ptr).get());
-}
-
-static inline Node* statementListInitializeDeclarationStacks(SourceElements& statements, DeclarationStacks::NodeStack& stack)
-{
-    for (SourceElements::iterator ptr = statements.end() - 1; ptr >= statements.begin(); --ptr)
-        if ((*ptr)->mayHaveDeclarations())
-             stack.append((*ptr).get());
+    SourceElements::iterator it = statements.end();
+    SourceElements::iterator begin = statements.begin();
+    while (it != begin) {
+        --it;
+        if ((*it)->mayHaveDeclarations())
+            stacks.nodeStack.append((*it).get());
+    }
+}
+
+static inline Node* statementListInitializeDeclarationStack(SourceElements& statements, DeclarationStacks::NodeStack& stack)
+{
+    ASSERT(!stack.size()); // Otherwise, the removeLast() call might remove someone else's node.
+    
+    SourceElements::iterator it = statements.end();
+    SourceElements::iterator begin = statements.begin();
+    
+    while (it != begin) {
+        --it;
+        if ((*it)->mayHaveDeclarations())
+             stack.append((*it).get());
+    }
+
     if (!stack.size())
         return 0;
+
     Node* n = stack.last();
     stack.removeLast();
@@ -3622 +3639 @@
 static inline Node* statementListInitializeVariableAccessStack(SourceElements& statements, DeclarationStacks::NodeStack& stack)
 {
-    for (SourceElements::iterator ptr = statements.end() - 1; ptr != statements.begin(); --ptr)
-        stack.append((*ptr).get());
-    return statements[0].get();
+    if (!statements.size())
+        return 0;
+
+    SourceElements::iterator it = statements.end();
+    SourceElements::iterator begin = statements.begin();
+    SourceElements::iterator beginPlusOne = begin + 1;
+    
+    while (it != beginPlusOne) {
+        --it;
+        stack.append((*it).get());
+    }
+
+    return (*begin).get();
 }
 
@@ -3647 +3674 @@
 // ------------------------------ BlockNode ------------------------------------
 
-void BlockNode::optimizeVariableAccess(FunctionBodyNode*, DeclarationStacks::NodeStack& nodeStack)
-{
-    if (m_children)
-        statementListPushFIFO(*m_children, nodeStack);
-}
-
 BlockNode::BlockNode(SourceElements* children)
 {
-  if (children) {
+    ASSERT(children);
     m_mayHaveDeclarations = true; 
     m_children.set(children);
-    setLoc(children->at(0)->firstLine(), children->at(children->size() - 1)->lastLine());
-  }
+}
+
+void BlockNode::optimizeVariableAccess(FunctionBodyNode*, DeclarationStacks::NodeStack& nodeStack)
+{
+    statementListPushFIFO(*m_children, nodeStack);
 }
 
 void BlockNode::getDeclarations(DeclarationStacks& stacks)
 { 
-    ASSERT(m_children);
     statementListGetDeclarations(*m_children, stacks);
 }
@@ -3671 +3694 @@
 Completion BlockNode::execute(ExecState *exec)
 {
-  if (!m_children)
-    return Completion(Normal);
-
-  return statementListExecute(*m_children, exec);
+    return statementListExecute(*m_children, exec);
 }
 
@@ -4404 +4424 @@
 void FunctionBodyNode::initializeDeclarationStacks(ExecState* exec)
 {
-    if (!m_children)
-        return;
-
     DeclarationStacks::NodeStack nodeStack;
     DeclarationStacks stacks(exec, nodeStack, m_varStack, m_functionStack);
-    Node* node = statementListInitializeDeclarationStacks(*m_children, nodeStack);
+    Node* node = statementListInitializeDeclarationStack(*m_children, nodeStack);
     if (!node)
         return;
@@ -4448 +4465 @@
 void FunctionBodyNode::optimizeVariableAccess()
 {
-    if (!m_children)
-        return;
-
     DeclarationStacks::NodeStack nodeStack;
     Node* node = statementListInitializeVariableAccessStack(*m_children, nodeStack);