gc: fix msvc not using libatomic_ops (#15418)

thirdparty/libatomic_ops/atomic_ops/sysdeps/gcc/sh.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2009 by Takashi YOSHII. All rights reserved.
+ *
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+
+#include "../all_atomic_load_store.h"
+#include "../ordered.h"
+
+/* sh has tas.b(byte) only */
+#include "../test_and_set_t_is_char.h"
+
+AO_INLINE AO_TS_VAL_t
+AO_test_and_set_full(volatile AO_TS_t *addr)
+{
+  int oldval;
+  __asm__ __volatile__(
+        "tas.b @%1; movt %0"
+        : "=r" (oldval)
+        : "r" (addr)
+        : "t", "memory");
+  return oldval? AO_TS_CLEAR : AO_TS_SET;
+}
+#define AO_HAVE_test_and_set_full
+
+/* TODO: Very incomplete.       */