Allocate room for expected number of properties based on the...

src/objects.h

 // Copyright 2006-2008 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 1331 matching lines @@
 
   // Convert the object to use the canonical dictionary
   // representation.
   Object* NormalizeProperties();
   Object* NormalizeElements();
 
   // Transform slow named properties to fast variants.
   // Returns failure if allocation failed.
   Object* TransformToFastProperties(int unused_property_fields);
 
+  // Access fast-case object properties at index.
+  inline Object* FastPropertyAt(int index);
+  inline Object* FastPropertyAtPut(int index, Object* value);
+
+
   // initializes the body after properties slot, properties slot is
   // initialized by set_properties
   // Note: this call does not update write barrier, it is caller's
   // reponsibility to ensure that *v* can be collected without WB here.
   inline void InitializeBody(int object_size);
 
   // Check whether this object references another object
   bool ReferencesObject(Object* obj);
 
   // Casting.
@@ skipping 885 matching lines @@
 // All heap objects have a Map that describes their structure.
 //  A Map contains information about:
 //  - Size information about the object
 //  - How to iterate over an object (for garbage collection)
 class Map: public HeapObject {
  public:
   // instance size.
   inline int instance_size();
   inline void set_instance_size(int value);
 
+  // Count of properties allocated in the object.
+  inline int inobject_properties();
+  inline void set_inobject_properties(int value);
+
   // instance type.
   inline InstanceType instance_type();
   inline void set_instance_type(InstanceType value);
 
   // tells how many unused property fields are available in the instance.
   // (only used for JSObject in fast mode).
   inline int unused_property_fields();
   inline void set_unused_property_fields(int value);
 
   // bit field.
@@ skipping 122 matching lines @@
   void RemoveFromCodeCache(int index);
 
   // Dispatched behavior.
   void MapIterateBody(ObjectVisitor* v);
 #ifdef DEBUG
   void MapPrint();
   void MapVerify();
 #endif
 
   // Layout description.
-  static const int kInstanceAttributesOffset = HeapObject::kHeaderSize;
+  static const int kInstanceSizesOffset = HeapObject::kHeaderSize;
+  static const int kInstanceAttributesOffset = kInstanceSizesOffset + kIntSize;
   static const int kPrototypeOffset = kInstanceAttributesOffset + kIntSize;
   static const int kConstructorOffset = kPrototypeOffset + kPointerSize;
   static const int kInstanceDescriptorsOffset =
       kConstructorOffset + kPointerSize;
   static const int kCodeCacheOffset = kInstanceDescriptorsOffset + kPointerSize;
   static const int kSize = kCodeCacheOffset + kIntSize;
 
+  // Byte offsets within kInstanceSizesOffset.
+  static const int kInstanceSizeOffset = kInstanceSizesOffset + 0;
+  static const int kInObjectPropertiesOffset = kInstanceSizesOffset + 1;
+  // The bytes at positions 2 and 3 are not in use at the moment.
+
+
   // Byte offsets within kInstanceAttributesOffset attributes.
-  static const int kInstanceSizeOffset = kInstanceAttributesOffset + 0;
-  static const int kInstanceTypeOffset = kInstanceAttributesOffset + 1;
-  static const int kUnusedPropertyFieldsOffset = kInstanceAttributesOffset + 2;
-  static const int kBitFieldOffset = kInstanceAttributesOffset + 3;
+  static const int kInstanceTypeOffset = kInstanceAttributesOffset + 0;
+  static const int kUnusedPropertyFieldsOffset = kInstanceAttributesOffset + 1;
+  static const int kBitFieldOffset = kInstanceAttributesOffset + 2;
+  // The  byte at position 3 is not in use at the moment.
 
   // Bit positions for bit field.
   static const int kUnused = 0;  // To be used for marking recently used maps.
   static const int kHasNonInstancePrototype = 1;
   static const int kIsHiddenPrototype = 2;
   static const int kHasNamedInterceptor = 3;
   static const int kHasIndexedInterceptor = 4;
   static const int kIsUndetectable = 5;
   static const int kHasInstanceCallHandler = 6;
   static const int kNeedsAccessCheck = 7;
@@ skipping 1575 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_