Grouping all map creation code.

src/objects.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 160 matching lines @@
 
 
 // Indicates whether the search function should expect a sorted or an unsorted
 // array as input.
 enum SearchMode {
   EXPECT_SORTED,
   EXPECT_UNSORTED
 };
 
 
+// Indicates whether transitions can be added to a source map or not.
+enum TransitionFlag {
+  INSERT_TRANSITION,
+  OMIT_TRANSITION
+};
+
+
 // Instance size sentinel for objects of variable size.
 const int kVariableSizeSentinel = 0;
 
 const int kStubMajorKeyBits = 6;
 const int kStubMinorKeyBits = kBitsPerInt - kSmiTagSize - kStubMajorKeyBits;
 
 // All Maps have a field instance_type containing a InstanceType.
 // It describes the type of the instances.
 //
 // As an example, a JavaScript object is a heap object and its map
@@ skipping 2357 matching lines @@
   inline void Append(Descriptor* desc,
                      const WhitenessWitness&);
 
   // Transfer a complete descriptor from the src descriptor array to this
   // descriptor array.
   void CopyFrom(int dst_index,
                 DescriptorArray* src,
                 int src_index,
                 const WhitenessWitness&);
 
-  // Copy the descriptor array, insert a new descriptor and optionally
-  // remove map transitions.  If the descriptor is already present, it is
-  // replaced.  If a replaced descriptor is a real property (not a transition
-  // or null), its enumeration index is kept as is.
-  // If adding a real property, map transitions must be removed.  If adding
-  // a transition, they must not be removed.  All null descriptors are removed.
-  MUST_USE_RESULT MaybeObject* CopyInsert(Descriptor* descriptor);
+  // Copy the descriptor array, inserting new descriptor. Its enumeration index
+  // is automatically set to the size of the descriptor array to which it was
+  // added first.
   MUST_USE_RESULT MaybeObject* CopyAdd(Descriptor* descriptor);
+
+  // Copy the descriptor array, replacing a descriptor. Its enumeration index is
+  // kept.
   MUST_USE_RESULT MaybeObject* CopyReplace(Descriptor* descriptor,
                                            int insertion_index);
 
   // Indicates whether the search function should expect a sorted or an unsorted
   // descriptor array as input.
   enum SharedMode {
     MAY_BE_SHARED,
     CANNOT_BE_SHARED
   };
 
@@ skipping 2326 matching lines @@
                         LookupResult* result);
 
   void LookupTransition(JSObject* holder,
                         String* name,
                         LookupResult* result);
 
   MUST_USE_RESULT MaybeObject* RawCopy(int instance_size);
   MUST_USE_RESULT MaybeObject* CopyWithPreallocatedFieldDescriptors();
   MUST_USE_RESULT MaybeObject* CopyDropDescriptors();
   MUST_USE_RESULT MaybeObject* CopyReplaceDescriptors(
-      DescriptorArray* descriptors);
+      DescriptorArray* descriptors, String* name, TransitionFlag flag);
+  MUST_USE_RESULT MaybeObject* CopyAddDescriptor(Descriptor* descriptor,
+                                                 TransitionFlag flag);
+  MUST_USE_RESULT MaybeObject* CopyInsertDescriptor(Descriptor* descriptor,
+                                                    TransitionFlag flag);
+  MUST_USE_RESULT MaybeObject* CopyReplaceDescriptor(Descriptor* descriptor,
+                                                     int index,
+                                                     TransitionFlag flag);
+  MUST_USE_RESULT MaybeObject* CopyAsElementsKind(ElementsKind kind,
+                                                  TransitionFlag flag);
 
   MUST_USE_RESULT MaybeObject* CopyNormalized(PropertyNormalizationMode mode,
                                               NormalizedMapSharingMode sharing);
 
   // Returns a copy of the map, with all transitions dropped from the
   // instance descriptors.
-  MUST_USE_RESULT MaybeObject* CopyDropTransitions(
-      DescriptorArray::SharedMode shared_mode);
+  MUST_USE_RESULT MaybeObject* Copy(DescriptorArray::SharedMode shared_mode);
 
   // Returns the property index for name (only valid for FAST MODE).
   int PropertyIndexFor(String* name);
 
   // Returns the next free property index (only valid for FAST MODE).
   int NextFreePropertyIndex();
 
   // Returns the number of properties described in instance_descriptors
   // filtering out properties with the specified attributes.
   int NumberOfDescribedProperties(PropertyAttributes filter = NONE);
@@ skipping 38 matching lines @@
   // it had exactly zero inobject properties.
   // The "shared" flags of both this map and |other| are ignored.
   bool EquivalentToForNormalization(Map* other, PropertyNormalizationMode mode);
 
   // Returns the map that this map transitions to if its elements_kind
   // is changed to |elements_kind|, or NULL if no such map is cached yet.
   // |safe_to_add_transitions| is set to false if adding transitions is not
   // allowed.
   Map* LookupElementsTransitionMap(ElementsKind elements_kind);
 
-  // Adds a new transitions for changing the elements kind to |elements_kind|.
-  MUST_USE_RESULT MaybeObject* CreateNextElementsTransition(
-      ElementsKind elements_kind);
-
   // Returns the transitioned map for this map with the most generic
   // elements_kind that's found in |candidates|, or null handle if no match is
   // found at all.
   Handle<Map> FindTransitionedMap(MapHandleList* candidates);
   Map* FindTransitionedMap(MapList* candidates);
 
   // Zaps the contents of backing data structures in debug mode. Note that the
   // heap verifier (i.e. VerifyMarkingVisitor) relies on zapping of objects
   // holding weak references when incremental marking is used, because it also
   // iterates over objects that are otherwise unreachable.
@@ skipping 3884 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_