diff --git a/internal/object.h b/internal/object.h
index f67293769a..959400a47a 100644
--- a/internal/object.h
+++ b/internal/object.h
@@ -9,37 +9,52 @@
  *             modify this file, provided that  the conditions mentioned in the
  *             file COPYING are met.  Consult the file for details.
  */
-
+#include "ruby/ruby.h"          /* for VALUE */
 
 /* object.c */
-void rb_obj_copy_ivar(VALUE dest, VALUE obj);
-CONSTFUNC(VALUE rb_obj_equal(VALUE obj1, VALUE obj2));
-CONSTFUNC(VALUE rb_obj_not(VALUE obj));
 VALUE rb_class_search_ancestor(VALUE klass, VALUE super);
 NORETURN(void rb_undefined_alloc(VALUE klass));
 double rb_num_to_dbl(VALUE val);
 VALUE rb_obj_dig(int argc, VALUE *argv, VALUE self, VALUE notfound);
 VALUE rb_immutable_obj_clone(int, VALUE *, VALUE);
-VALUE rb_obj_not_equal(VALUE obj1, VALUE obj2);
-VALUE rb_convert_type_with_id(VALUE,int,const char*,ID);
 VALUE rb_check_convert_type_with_id(VALUE,int,const char*,ID);
 int rb_bool_expected(VALUE, const char *);
-
-struct RBasicRaw {
-    VALUE flags;
-    VALUE klass;
-};
-
-#define RBASIC_CLEAR_CLASS(obj)        memset(&(((struct RBasicRaw *)((VALUE)(obj)))->klass), 0, sizeof(VALUE))
-#define RBASIC_SET_CLASS_RAW(obj, cls) memcpy(&((struct RBasicRaw *)((VALUE)(obj)))->klass, &(cls), sizeof(VALUE))
-#define RBASIC_SET_CLASS(obj, cls)     do { \
-    VALUE _obj_ = (obj); \
-    RB_OBJ_WRITE(_obj_, &((struct RBasicRaw *)(_obj_))->klass, cls); \
-} while (0)
+static inline void RBASIC_CLEAR_CLASS(VALUE obj);
+static inline void RBASIC_SET_CLASS_RAW(VALUE obj, VALUE klass);
+static inline void RBASIC_SET_CLASS(VALUE obj, VALUE klass);
 
 RUBY_SYMBOL_EXPORT_BEGIN
 /* object.c (export) */
 int rb_opts_exception_p(VALUE opts, int default_value);
 RUBY_SYMBOL_EXPORT_END
 
+MJIT_SYMBOL_EXPORT_BEGIN
+CONSTFUNC(VALUE rb_obj_equal(VALUE obj1, VALUE obj2));
+CONSTFUNC(VALUE rb_obj_not(VALUE obj));
+VALUE rb_obj_not_equal(VALUE obj1, VALUE obj2);
+void rb_obj_copy_ivar(VALUE dest, VALUE obj);
+VALUE rb_false(VALUE obj);
+VALUE rb_convert_type_with_id(VALUE v, int t, const char* nam, ID mid);
+MJIT_SYMBOL_EXPORT_END
+
+static inline void
+RBASIC_SET_CLASS_RAW(VALUE obj, VALUE klass)
+{
+    struct { VALUE flags; VALUE klass; } *ptr = (void *)obj;
+    ptr->klass = klass;
+}
+
+static inline void
+RBASIC_CLEAR_CLASS(VALUE obj)
+{
+    RBASIC_SET_CLASS_RAW(obj, 0);
+}
+
+static inline void
+RBASIC_SET_CLASS(VALUE obj, VALUE klass)
+{
+    VALUE oldv = RBASIC_CLASS(obj);
+    RBASIC_SET_CLASS_RAW(obj, klass);
+    RB_OBJ_WRITTEN(obj, oldv, klass);
+}
 #endif /* INTERNAL_OBJECT_H */