Add IsStackAllocated helper for variables.

Add a simple boolean helper function for Variables and Slots.

Review URL: http://codereview.chromium.org/722001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4065 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ast.h

@@ -1047,6 +1047,8 @@ class Slot: public Expression {
 
   virtual bool IsLeaf() { return true; }
 
+  bool IsStackAllocated() { return type_ == PARAMETER || type_ == LOCAL; }
+
   // Accessors
   Variable* var() const { return var_; }
   Type type() const { return type_; }

src/data-flow.cc

@@ -433,11 +433,7 @@ void FlowGraphBuilder::VisitAssignment(Assignment* expr) {
   ASSERT(var == NULL || prop == NULL);
   if (var != NULL) {
     Visit(expr->value());
-    Slot* slot = var->slot();
-    if (slot != NULL &&
-        (slot->type() == Slot::LOCAL || slot->type() == Slot::PARAMETER)) {
-      definitions_.Add(expr);
-    }
+    if (var->IsStackAllocated()) definitions_.Add(expr);
 
   } else if (prop != NULL) {
     Visit(prop->obj());
@@ -499,12 +495,8 @@ void FlowGraphBuilder::VisitUnaryOperation(UnaryOperation* expr) {
 void FlowGraphBuilder::VisitCountOperation(CountOperation* expr) {
   Visit(expr->expression());
   Variable* var = expr->expression()->AsVariableProxy()->AsVariable();
-  if (var != NULL) {
-    Slot* slot = var->slot();
-    if (slot != NULL &&
-        (slot->type() == Slot::LOCAL || slot->type() == Slot::PARAMETER)) {
-      definitions_.Add(expr);
-    }
+  if (var != NULL && var->IsStackAllocated()) {
+    definitions_.Add(expr);
   }
   graph_.AppendInstruction(expr);
 }

src/rewriter.cc

@@ -246,11 +246,8 @@ void AstOptimizer::VisitVariableProxy(VariableProxy* node) {
     }
 
     if (FLAG_safe_int32_compiler) {
-      Slot* slot = var->slot();
-      if (slot != NULL) {
-        node->set_side_effect_free(
-            (slot->type() == Slot::LOCAL  && !slot->is_arguments()) ||
-            slot->type() == Slot::PARAMETER);
+      if (var->IsStackAllocated() && !var->is_arguments()) {
+        node->set_side_effect_free(true);
       }
     }
   }

src/variables.cc

@@ -85,6 +85,12 @@ Slot* Variable::slot() const {
 }
 
 
+bool Variable::IsStackAllocated() const {
+  Slot* s = slot();
+  return s != NULL && s->IsStackAllocated();
+}
+
+
 Variable::Variable(Scope* scope,
                    Handle<String> name,
                    Mode mode,

src/variables.h

@@ -146,6 +146,8 @@ class Variable: public ZoneObject {
     return !is_this() && name().is_identical_to(n);
   }
 
+  bool IsStackAllocated() const;
+
   bool is_dynamic() const {
     return (mode_ == DYNAMIC ||
             mode_ == DYNAMIC_GLOBAL ||