Make the sizer for function for TypedData a hidden ivar instead of HiddenKey

* This enables sharing to work normally, HiddenKey should only be used
  for fixed Layouts and primitives.
* Fix the return value of ObjectSpace.memsize_of for non-C-ext objects.

Author: eregon

lib/truffle/objspace.rb

@@ -154,7 +154,12 @@ def dump_all(output: :file)
   def memsize_of(object)
     size = Truffle::ObjSpace.memsize_of(object)
 
-    size + Truffle::ObjSpace.sizer(object).call unless Truffle::ObjSpace.sizer(object).nil?
+    memsizer = Truffle::CExt.hidden_variable_get object, :data_memsizer
+    if memsizer
+      size + memsizer.call
+    else
+      size
+    end
   end
   module_function :memsize_of
 

lib/truffle/truffle/cext.rb

@@ -1449,8 +1449,10 @@ def rb_data_typed_object_wrap(ruby_class, data, data_type, mark, free, size)
     data_holder = DataHolder.new(data)
     hidden_variable_set object, :data_type, data_type
     hidden_variable_set object, :data_holder, data_holder
+    hidden_variable_set object, :data_memsizer, data_sizer(size, data_holder) unless size.nil?
+
     ObjectSpace.define_finalizer object, data_finalizer(free, data_holder) unless free.nil?
-    Truffle::ObjSpace.define_sizer object, data_sizer(size, data_holder) unless size.nil?
+
     define_marker object, data_marker(mark, data_holder) unless mark.nil?
     object
   end

src/main/java/org/truffleruby/Layouts.java

@@ -104,7 +104,6 @@ public abstract class Layouts {
     public static final HiddenKey ASSOCIATED_IDENTIFIER = new HiddenKey("associated");
     public static final HiddenKey FINALIZER_REF_IDENTIFIER = new HiddenKey("finalizerRef");
     public static final HiddenKey MARKED_OBJECTS_IDENTIFIER = new HiddenKey("marked_objects");
-    public static final HiddenKey MEMSIZER_IDENTIFIER = new HiddenKey("memsizer");
     public static final HiddenKey VALUE_WRAPPER_IDENTIFIER = new HiddenKey("value_wrapper");
 
     // Generated layouts

src/main/java/org/truffleruby/stdlib/ObjSpaceNodes.java

@@ -71,29 +71,6 @@ public int memsize(Object object) {
         }
     }
 
-    @CoreMethod(names = "sizer", isModuleFunction = true, required = 1)
-    public abstract static class GetMemSizer extends CoreMethodArrayArgumentsNode {
-
-        @Child private ReadObjectFieldNode readSizerNode = ReadObjectFieldNodeGen.create(Layouts.MEMSIZER_IDENTIFIER, nil());
-
-        @Specialization
-        public Object hasSizer(DynamicObject object) {
-            return readSizerNode.execute(object);
-        }
-    }
-
-    @CoreMethod(names = "define_sizer", isModuleFunction = true, required = 2)
-    public abstract static class DefineMemSizer extends CoreMethodArrayArgumentsNode {
-
-        @Child private WriteObjectFieldNode setSizerNode = WriteObjectFieldNodeGen.create(Layouts.MEMSIZER_IDENTIFIER);
-
-        @Specialization
-        public DynamicObject defineSizer(DynamicObject object, DynamicObject sizer) {
-            setSizerNode.write(object, sizer);
-            return nil();
-        }
-    }
-
     @CoreMethod(names = "adjacent_objects", isModuleFunction = true, required = 1)
     public abstract static class AdjacentObjectsNode extends CoreMethodArrayArgumentsNode {