V8 support for cached accessors.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 08e1e568a2fb3f1c689e44c57fb05b6e566f115c..dbfe2e93ad6c3a728687cef1dba9b845cd6864af 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -11470,6 +11470,8 @@ class FunctionTemplateInfo: public TemplateInfo {
   DECL_BOOLEAN_ACCESSORS(do_not_cache)
   DECL_BOOLEAN_ACCESSORS(accept_any_receiver)
 
+  DECL_ACCESSORS(cached_property_name, Object)
+
   DECLARE_CAST(FunctionTemplateInfo)
 
   // Dispatched behavior.
@@ -11496,7 +11498,8 @@ class FunctionTemplateInfo: public TemplateInfo {
       kAccessCheckInfoOffset + kPointerSize;
   static const int kFlagOffset = kSharedFunctionInfoOffset + kPointerSize;
   static const int kLengthOffset = kFlagOffset + kPointerSize;
-  static const int kSize = kLengthOffset + kPointerSize;
+  static const int kCachedPropertyNameOffset = kLengthOffset + kPointerSize;
+  static const int kSize = kCachedPropertyNameOffset + kPointerSize;
 
   static Handle<SharedFunctionInfo> GetOrCreateSharedFunctionInfo(
       Isolate* isolate, Handle<FunctionTemplateInfo> info);
@@ -11507,6 +11510,10 @@ class FunctionTemplateInfo: public TemplateInfo {
   bool IsTemplateFor(Map* map);
   inline bool instantiated();
 
+  // Helper function for cached accessors.
+  static MaybeHandle<Name> TryGetCachedPropertyName(Isolate* isolate,
+                                                    Handle<Object> getter);
+
  private:
   // Bit position in the flag, from least significant bit position.
   static const int kHiddenPrototypeBit   = 0;