vm_core.h: CoreDataFromValue

* vm_core.h (CoreDataFromValue): split as an expression from
  GetCoreDataFromValue, which can be a statement only.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53888 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

vm_core.h

@@ -250,12 +250,11 @@ struct rb_call_cache {
 };
 
 #if 1
-#define GetCoreDataFromValue(obj, type, ptr) do { \
-    (ptr) = (type*)DATA_PTR(obj); \
-} while (0)
+#define CoreDataFromValue(obj, type) (type*)DATA_PTR(obj)
 #else
-#define GetCoreDataFromValue(obj, type, ptr) Data_Get_Struct((obj), type, (ptr))
+#define CoreDataFromValue(obj, type) (type*)rb_data_object_get(obj)
 #endif
+#define GetCoreDataFromValue(obj, type, ptr) ((ptr) = CoreDataFromValue((obj), type))
 
 typedef struct rb_iseq_location_struct {
     VALUE path;