This change rewrites some of the code to add properties to an object.

It removes the ReplaceConstantFunction code, and replaces it with
new ConvertDescriptorToField code, that is also used in other places.
Functions CopyRemove and CopyReplace on DescriptorArray are removed.
Function AddFastProperty is simplified by removing the 
CONSTANT_TRANSITION case.
Review URL: http://codereview.chromium.org/6528

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@475 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/objects.h

@@ -1303,9 +1303,26 @@ class JSObject: public HeapObject {
                                       JSFunction* function,
                                       PropertyAttributes attributes);
 
-  // Replace a constant function property on a fast-case object.
-  Object* ReplaceConstantFunctionProperty(String* name,
-                                          Object* value);
+  Object* ReplaceSlowProperty(String* name,
+                              Object* value,
+                              PropertyAttributes attributes);
+
+  // Converts a descriptor of any other type to a real field,
+  // backed by the properties array.  Descriptors of visible
+  // types, such as CONSTANT_FUNCTION, keep their enumeration order.
+  // Converts the descriptor on the original object's map to a
+  // map transition, and the the new field is on the object's new map.
+  Object* ConvertDescriptorToFieldAndMapTransition(
+      String* name,
+      Object* new_value,
+      PropertyAttributes attributes);
+
+  // Converts a descriptor of any other type to a real field,
+  // backed by the properties array.  Descriptors of visible
+  // types, such as CONSTANT_FUNCTION, keep their enumeration order.
+  Object* ConvertDescriptorToField(String* name,
+                                   Object* new_value,
+                                   PropertyAttributes attributes);
 
   // Add a property to a fast-case object.
   Object* AddFastProperty(String* name,
@@ -1377,6 +1394,10 @@ class JSObject: public HeapObject {
   static const uint32_t kMaxGap = 1024;
   static const int kMaxFastElementsLength = 5000;
   static const int kMaxFastProperties = 8;
+  // When extending the backing storage for property values, we increase
+  // its size by more than the 1 entry necessary, so sequentially adding fields
+  // to the same object requires fewer allocations and copies.
+  static const int kFieldsAdded = 3;
 
   // Layout description.
   static const int kPropertiesOffset = HeapObject::kHeaderSize;
@@ -1562,7 +1583,6 @@ class DescriptorArray: public FixedArray {
   inline void Get(int descriptor_number, Descriptor* desc);
   inline void Set(int descriptor_number, Descriptor* desc);
 
-  void ReplaceConstantFunction(int descriptor_number, JSFunction* value);
 
   // Copy the descriptor array, insert a new descriptor and optionally
   // remove map transitions.  If the descriptor is already present, it is
@@ -1572,20 +1592,6 @@ class DescriptorArray: public FixedArray {
   // a transition, they must not be removed.  All null descriptors are removed.
   Object* CopyInsert(Descriptor* descriptor, TransitionFlag transition_flag);
 
-  // Makes a copy of the descriptor array with the descriptor with key name
-  // removed.  If name is the empty string, the descriptor array is copied.
-  // Transitions are removed if TransitionFlag is REMOVE_TRANSITIONS.
-  // All null descriptors are removed.
-  Object* CopyRemove(TransitionFlag remove_transitions, String* name);
-
-  // Copy the descriptor array, replace the property index and attributes
-  // of the named property, but preserve its enumeration index.
-  Object* CopyReplace(String* name, int index, PropertyAttributes attributes);
-
-  // Copy the descriptor array, removing the property index and attributes
-  // of the named property.
-  Object* CopyRemove(String* name);
-
   // Remove all transitions.  Return  a copy of the array with all transitions
   // removed, or a Failure object if the new array could not be allocated.
   Object* RemoveTransitions();