Increment descriptor array slack for prototypes by a constant rather than 50%

src/objects.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 6003 matching lines @@
   // Update code cache.
   static void UpdateCodeCache(Handle<Map> map,
                               Handle<Name> name,
                               Handle<Code> code);
 
   // Extend the descriptor array of the map with the list of descriptors.
   // In case of duplicates, the latest descriptor is used.
   static void AppendCallbackDescriptors(Handle<Map> map,
                                         Handle<Object> descriptors);
 
-  static inline int SlackForArraySize(int old_size, int size_limit);
+  static inline int SlackForArraySize(bool is_prototype_map, int old_size,
+                                      int size_limit);
 
   static void EnsureDescriptorSlack(Handle<Map> map, int slack);
 
   // Returns the found code or undefined if absent.
   Object* FindInCodeCache(Name* name, Code::Flags flags);
 
   // Returns the non-negative index of the code object if it is in the
   // cache and -1 otherwise.
   int IndexInCodeCache(Object* name, Code* code);
 
@@ skipping 4410 matching lines @@
   static const int kSize = kDataOffset + kPointerSize;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(CallHandlerInfo);
 };
 
 
 class TemplateInfo: public Struct {
  public:
   DECL_ACCESSORS(tag, Object)
+  inline int number_of_properties() const;
+  inline void set_number_of_properties(int value);
   DECL_ACCESSORS(property_list, Object)
   DECL_ACCESSORS(property_accessors, Object)
 
   DECLARE_VERIFIER(TemplateInfo)
 
   static const int kTagOffset = HeapObject::kHeaderSize;
-  static const int kPropertyListOffset = kTagOffset + kPointerSize;
+  static const int kNumberOfProperties = kTagOffset + kPointerSize;
+  static const int kPropertyListOffset = kNumberOfProperties + kPointerSize;
   static const int kPropertyAccessorsOffset =
       kPropertyListOffset + kPointerSize;
   static const int kHeaderSize = kPropertyAccessorsOffset + kPointerSize;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(TemplateInfo);
 };
 
 
 class FunctionTemplateInfo: public TemplateInfo {
@@ skipping 350 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_