1 files changed, 12 insertions, 0 deletions
diff --git a/mjit.h b/mjit.h
index 0efa04ac8d..1a339deaa9 100644
--- a/mjit.h
+++ b/mjit.h
@@ -11,6 +11,18 @@
 
 #include "ruby.h"
 
+/* On mswin, MJIT header transformation can't be used since cl.exe can't output
+   preprocessed output preserving macros. So this `MJIT_STATIC` is needed
+   to force non-static function to static on MJIT header to avoid symbol conflict.
+   `MJIT_FUNC_EXPORTED` is also changed to `static` on MJIT header for the same reason. */
+#ifdef MJIT_HEADER
+# define MJIT_STATIC static
+# undef MJIT_FUNC_EXPORTED
+# define MJIT_FUNC_EXPORTED static
+#else
+# define MJIT_STATIC
+#endif
+
 /* Special address values of a function generated from the
    corresponding iseq by MJIT: */
 enum rb_mjit_iseq_func {