Change heuristic to determine which fields contain modifieable double boxes: do it if field was ini…

runtime/vm/object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 2799 matching lines @@
   RawString* PrettyName() const;
   RawString* UserVisibleName() const;
   virtual RawString* DictionaryName() const { return name(); }
 
   bool is_static() const { return StaticBit::decode(raw_ptr()->kind_bits_); }
   bool is_final() const { return FinalBit::decode(raw_ptr()->kind_bits_); }
   bool is_const() const { return ConstBit::decode(raw_ptr()->kind_bits_); }
   bool is_synthetic() const {
     return SyntheticBit::decode(raw_ptr()->kind_bits_);
   }
+  bool is_double_initialized() const {
+    return DoubleInitializedBit::decode(raw_ptr()->kind_bits_);
+  }
+  void set_is_double_initialized(bool value) const {
+    set_kind_bits(DoubleInitializedBit::update(value, raw_ptr()->kind_bits_));
+  }
+
 
   inline intptr_t Offset() const;
   inline void SetOffset(intptr_t value_in_bytes) const;
 
   RawInstance* value() const;
   void set_value(const Instance& value) const;
 
   RawClass* owner() const;
   RawClass* origin() const;  // Either mixin class, or same as owner().
 
@@ skipping 150 matching lines @@
 
  private:
   friend class StoreInstanceFieldInstr;  // Generated code access to bit field.
 
   enum {
     kConstBit = 0,
     kStaticBit,
     kFinalBit,
     kHasInitializerBit,
     kUnboxingCandidateBit,
-    kSyntheticBit
+    kSyntheticBit,
+    kDoubleInitializedBit,
   };
   class ConstBit : public BitField<bool, kConstBit, 1> {};
   class StaticBit : public BitField<bool, kStaticBit, 1> {};
   class FinalBit : public BitField<bool, kFinalBit, 1> {};
   class HasInitializerBit : public BitField<bool, kHasInitializerBit, 1> {};
   class UnboxingCandidateBit : public BitField<bool,
-                                               kUnboxingCandidateBit, 1> {
-  };
+                                               kUnboxingCandidateBit, 1> {};
   class SyntheticBit : public BitField<bool, kSyntheticBit, 1> {};
+  class DoubleInitializedBit : public BitField<bool,
+                                               kDoubleInitializedBit, 1> {};
 
   // Update guarded cid and guarded length for this field. Returns true, if
   // deoptimization of dependent code is required.
   bool UpdateGuardedCidAndLength(const Object& value) const;
 
   void set_name(const String& value) const;
   void set_is_static(bool is_static) const {
     set_kind_bits(StaticBit::update(is_static, raw_ptr()->kind_bits_));
   }
   void set_is_final(bool is_final) const {
@@ skipping 5021 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_