Save zone memory in LEnvironment by using a bit vector.

src/lithium.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 435 matching lines @@
                LEnvironment* outer)
       : closure_(closure),
         is_arguments_adaptor_(is_arguments_adaptor),
         arguments_stack_height_(argument_count),
         deoptimization_index_(Safepoint::kNoDeoptimizationIndex),
         translation_index_(-1),
         ast_id_(ast_id),
         parameter_count_(parameter_count),
         pc_offset_(-1),
         values_(value_count),
-        representations_(value_count),
+        is_tagged_(value_count),
         spilled_registers_(NULL),
         spilled_double_registers_(NULL),
         outer_(outer) {
   }
 
   Handle<JSFunction> closure() const { return closure_; }
   int arguments_stack_height() const { return arguments_stack_height_; }
   int deoptimization_index() const { return deoptimization_index_; }
   int translation_index() const { return translation_index_; }
   int ast_id() const { return ast_id_; }
   int parameter_count() const { return parameter_count_; }
   int pc_offset() const { return pc_offset_; }
   LOperand** spilled_registers() const { return spilled_registers_; }
   LOperand** spilled_double_registers() const {
     return spilled_double_registers_;
   }
   const ZoneList<LOperand*>* values() const { return &values_; }
   LEnvironment* outer() const { return outer_; }
 
   void AddValue(LOperand* operand, Representation representation) {
     values_.Add(operand);
-    representations_.Add(representation);
+    if (representation.IsTagged()) {
+      is_tagged_.Add(values_.length() - 1);
+    }
   }
 
   bool HasTaggedValueAt(int index) const {
-    return representations_[index].IsTagged();
+    return is_tagged_.Contains(index);
   }
 
   void Register(int deoptimization_index,
                 int translation_index,
                 int pc_offset) {
     ASSERT(!HasBeenRegistered());
     deoptimization_index_ = deoptimization_index;
     translation_index_ = translation_index;
     pc_offset_ = pc_offset;
   }
@@ skipping 14 matching lines @@
  private:
   Handle<JSFunction> closure_;
   bool is_arguments_adaptor_;
   int arguments_stack_height_;
   int deoptimization_index_;
   int translation_index_;
   int ast_id_;
   int parameter_count_;
   int pc_offset_;
   ZoneList<LOperand*> values_;
-  ZoneList<Representation> representations_;
+  BitVector is_tagged_;
 
   // Allocation index indexed arrays of spill slot operands for registers
   // that are also in spill slots at an OSR entry.  NULL for environments
   // that do not correspond to an OSR entry.
   LOperand** spilled_registers_;
   LOperand** spilled_double_registers_;
 
   LEnvironment* outer_;
 };
 
@@ skipping 71 matching lines @@
   ShallowIterator current_iterator_;
 };
 
 
 int ElementsKindToShiftSize(ElementsKind elements_kind);
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_LITHIUM_H_