Group lexical context variables for faster look up.

src/scopes.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/bootstrapper.h"
 #include "src/messages.h"
 #include "src/parser.h"
@@ skipping 575 matching lines @@
   return NULL;
 }
 
 
 class VarAndOrder {
  public:
   VarAndOrder(Variable* var, int order) : var_(var), order_(order) { }
   Variable* var() const { return var_; }
   int order() const { return order_; }
   static int Compare(const VarAndOrder* a, const VarAndOrder* b) {
-    return a->order_ - b->order_;
+    // Sort lexical variables to the end of the list.
+    bool a_is_lexical = IsLexicalVariableMode(a->var()->mode());
+    bool b_is_lexical = IsLexicalVariableMode(b->var()->mode());
+    if (a_is_lexical == b_is_lexical) return a->order_ - b->order_;
+    return a_is_lexical ? 1 : -1;
   }
 
  private:
   Variable* var_;
   int order_;
 };
 
 
 void Scope::CollectStackAndContextLocals(
     ZoneList<Variable*>* stack_locals, ZoneList<Variable*>* context_locals,
@@ skipping 999 matching lines @@
       function_ != NULL && function_->proxy()->var()->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS - num_global_slots() -
          (is_function_var_in_context ? 1 : 0);
 }
 
 
 int Scope::ContextGlobalCount() const { return num_global_slots(); }
 
 }  // namespace internal
 }  // namespace v8