Changeset 27501 in webkit for trunk/JavaScriptCore/kjs/nodes.h

Timestamp:

Nov 6, 2007, 10:03:20 PM (18 years ago)

Author:

oliver

Message:

Avoid unnecessarily boxing the result from post inc/decrement for 0.3% gain in sunspider

Reviewed by Maciej

We now convert the common 'for (...; ...; <var>++) ...' to the semantically identical
'for (...; ...; ++<var>) ...'.

File:

• trunk/JavaScriptCore/kjs/nodes.h (modified) (11 diffs)

trunk/JavaScriptCore/kjs/nodes.h

@@ -143 +143 @@
     virtual void optimizeVariableAccess(FunctionBodyNode*, DeclarationStacks::NodeStack&) KJS_FAST_CALL { }
 
+    // Used to optimize those nodes that do extra work when returning a result, even if the result has no semantic relevance
+    virtual void optimizeForUnnecessaryResult() { }
+      
   protected:
     Completion createErrorCompletion(ExecState *, ErrorType, const char *msg) KJS_FAST_CALL;
@@ -539 +542 @@
   };
 
-  class PostIncResolveNode : public Node {
-  public:
-    PostIncResolveNode(const Identifier& i) KJS_FAST_CALL : m_ident(i) {}
-
-    PostIncResolveNode(PlacementNewAdoptType) KJS_FAST_CALL 
+  class PrePostResolveNode : public Node {
+  public:
+    PrePostResolveNode(const Identifier& i) KJS_FAST_CALL : m_ident(i) {}
+      
+    PrePostResolveNode(PlacementNewAdoptType) KJS_FAST_CALL 
         : Node(PlacementNewAdopt)
         , m_ident(PlacementNewAdopt)
     {
     }
+      
+  protected:
+      Identifier m_ident;
+      size_t m_index; // Used by LocalVarPostfixNode.      
+  };
+    
+  class PostIncResolveNode : public PrePostResolveNode {
+  public:
+    PostIncResolveNode(const Identifier& i) KJS_FAST_CALL : PrePostResolveNode(i) {}
+
+    PostIncResolveNode(PlacementNewAdoptType) KJS_FAST_CALL 
+        : PrePostResolveNode(PlacementNewAdopt)
+    {
+    }
 
     virtual void optimizeVariableAccess(FunctionBodyNode*, DeclarationStacks::NodeStack&) KJS_FAST_CALL;
@@ -553 +570 @@
     virtual void streamTo(SourceStream&) const KJS_FAST_CALL;
     virtual Precedence precedence() const { return PrecPostfix; }
-
-  protected:
-    Identifier m_ident;
-    size_t index; // Used by LocalVarPostfixNode.
+    virtual void optimizeForUnnecessaryResult();
+
   };
 
@@ -565 +580 @@
     {
         ASSERT(i != missingSymbolMarker());
-        index = i;
-    }
-
-    JSValue* evaluate(ExecState*) KJS_FAST_CALL;
-  };
-
-  class PostDecResolveNode : public Node {
-  public:
-    PostDecResolveNode(const Identifier& i) KJS_FAST_CALL : m_ident(i) {}
+        m_index = i;
+    }
+
+    JSValue* evaluate(ExecState*) KJS_FAST_CALL;
+    virtual void optimizeForUnnecessaryResult();
+  };
+
+  class PostDecResolveNode : public PrePostResolveNode {
+  public:
+    PostDecResolveNode(const Identifier& i) KJS_FAST_CALL : PrePostResolveNode(i) {}
 
     PostDecResolveNode(PlacementNewAdoptType) KJS_FAST_CALL 
-        : Node(PlacementNewAdopt)
-        , m_ident(PlacementNewAdopt)
+        : PrePostResolveNode(PlacementNewAdopt)
     {
     }
@@ -585 +600 @@
     virtual void streamTo(SourceStream&) const KJS_FAST_CALL;
     virtual Precedence precedence() const { return PrecPostfix; }
-
-  protected:
-    Identifier m_ident;
-    size_t index; // Used by LocalVarPostfixNode.
+    virtual void optimizeForUnnecessaryResult();
   };
 
@@ -597 +609 @@
     {
         ASSERT(i != missingSymbolMarker());
-        index = i;
-    }
-
-    JSValue* evaluate(ExecState*) KJS_FAST_CALL;
+        m_index = i;
+    }
+
+    JSValue* evaluate(ExecState*) KJS_FAST_CALL;
+    virtual void optimizeForUnnecessaryResult();
   };
 
@@ -792 +805 @@
   };
 
-  class PreIncResolveNode : public Node {
+  class PreIncResolveNode : public PrePostResolveNode {
   public:
     PreIncResolveNode(const Identifier &s) KJS_FAST_CALL 
-        : m_ident(s) 
+        : PrePostResolveNode(s) 
     { 
     }
     
     PreIncResolveNode(PlacementNewAdoptType) KJS_FAST_CALL 
-        : Node(PlacementNewAdopt)
-        , m_ident(PlacementNewAdopt) 
+        : PrePostResolveNode(PlacementNewAdopt)
     {
     }
@@ -810 +822 @@
     virtual void streamTo(SourceStream&) const KJS_FAST_CALL;
     virtual Precedence precedence() const { return PrecUnary; }
-
-  protected:
-    Identifier m_ident;
-    size_t m_index; // Used by LocalVarPrefixNode.
   };
 
@@ -828 +836 @@
   };
   
-  class PreDecResolveNode : public Node {
+  class PreDecResolveNode : public PrePostResolveNode {
   public:
     PreDecResolveNode(const Identifier &s) KJS_FAST_CALL 
-        : m_ident(s) 
+        : PrePostResolveNode(s) 
     { 
     }
     
     PreDecResolveNode(PlacementNewAdoptType) KJS_FAST_CALL 
-        : Node(PlacementNewAdopt)
-        , m_ident(PlacementNewAdopt) 
+        : PrePostResolveNode(PlacementNewAdopt)
     {
     }
@@ -846 +853 @@
     virtual void streamTo(SourceStream&) const KJS_FAST_CALL;
     virtual Precedence precedence() const { return PrecUnary; }
-
-  protected:
-    Identifier m_ident;
-    size_t m_index; // Used by LocalVarPrefixNode.
   };
 
@@ -1562 +1565 @@
   public:
     ForNode(Node* e1, Node* e2, Node* e3, StatementNode* s) KJS_FAST_CALL :
-      expr1(e1), expr2(e2), expr3(e3), statement(s) { m_mayHaveDeclarations = true; }
+      expr1(e1), expr2(e2), expr3(e3), statement(s)
+    {
+        m_mayHaveDeclarations = true; 
+        if (expr3)
+            expr3->optimizeForUnnecessaryResult();
+    }
+
     virtual void optimizeVariableAccess(FunctionBodyNode*, DeclarationStacks::NodeStack&) KJS_FAST_CALL;
     virtual Completion execute(ExecState*) KJS_FAST_CALL;