Make order of addition the primary order of descriptor arrays.

src/property-details.h

Index: src/property-details.h
diff --git a/src/property-details.h b/src/property-details.h
index 51b889a6670f22df4f107712ed079cfa383ff531..b8fbb3c92a8d413822c6d1bb3ea23d14d20524c9 100644
--- a/src/property-details.h
+++ b/src/property-details.h
@@ -77,19 +77,19 @@ class PropertyDetails BASE_EMBEDDED {
   PropertyDetails(PropertyAttributes attributes,
                   PropertyType type,
                   int index = 0) {
-    ASSERT(TypeField::is_valid(type));
-    ASSERT(AttributesField::is_valid(attributes));
-    ASSERT(StorageField::is_valid(index));
-
     value_ = TypeField::encode(type)
         | AttributesField::encode(attributes)
-        | StorageField::encode(index);
+        | DictionaryStorageField::encode(index);
 
     ASSERT(type == this->type());
     ASSERT(attributes == this->attributes());
-    ASSERT(index == this->index());
+    ASSERT(index == this->dictionary_index());
   }
 
+  int pointer() { return DescriptorPointer::decode(value_); }
+
+  PropertyDetails set_pointer(int i) { return PropertyDetails(value_, i); }
+
   // Conversion for storing details as Object*.
   explicit inline PropertyDetails(Smi* smi);
   inline Smi* AsSmi();
@@ -98,12 +98,18 @@ class PropertyDetails BASE_EMBEDDED {
 
   PropertyAttributes attributes() { return AttributesField::decode(value_); }
 
-  int index() { return StorageField::decode(value_); }
+  int dictionary_index() {
+    return DictionaryStorageField::decode(value_);
+  }
+
+  int descriptor_index() {
+    return DescriptorStorageField::decode(value_);
+  }
 
   inline PropertyDetails AsDeleted();
 
   static bool IsValidIndex(int index) {
-    return StorageField::is_valid(index);
+    return DictionaryStorageField::is_valid(index);
   }
 
   bool IsReadOnly() { return (attributes() & READ_ONLY) != 0; }
@@ -113,14 +119,20 @@ class PropertyDetails BASE_EMBEDDED {
 
   // Bit fields in value_ (type, shift, size). Must be public so the
   // constants can be embedded in generated code.
-  class TypeField:       public BitField<PropertyType,       0, 3> {};
-  class AttributesField: public BitField<PropertyAttributes, 3, 3> {};
-  class DeletedField:    public BitField<uint32_t,           6, 1> {};
-  class StorageField:    public BitField<uint32_t,           7, 32-7> {};
+  class TypeField:                public BitField<PropertyType,       0,  3> {};
+  class AttributesField:          public BitField<PropertyAttributes, 3,  3> {};
+  class DeletedField:             public BitField<uint32_t,           6,  1> {};
+  class DictionaryStorageField:   public BitField<uint32_t,           7, 24> {};
+  class DescriptorStorageField:   public BitField<uint32_t,           7, 11> {};
+  class DescriptorPointer:        public BitField<uint32_t,          18, 11> {};
 
   static const int kInitialIndex = 1;
 
  private:
+  PropertyDetails(int value, int pointer) {
+      value_ = DescriptorPointer::update(value, pointer);
+  }
+
   uint32_t value_;
 };