-/* This is outrageous! */
-#define QCINT_ENTRY void*
-#define QCINT_TO_HASH_ENTRY(q) ((void*)(uintptr_t)(q))
-#define HASH_ENTRY_TO_QCINT(h) ((qcint)(uintptr_t)(h))
+/*
+ * We could use the old method of casting to uintptr_t then to void*
+ * or qcint; however, it's incredibly unsafe for two reasons.
+ * 1) The compilers aliasing optimization can legally make it unstable
+ * (it's undefined behaviour).
+ *
+ * 2) The cast itself depends on fresh storage (newly allocated in which
+ * ever function is using the cast macros), the contents of which are
+ * transferred in a way that the obligation to release storage is not
+ * propagated.
+ */
+typedef union {
+ void *enter;
+ qcint leave;
+} code_hash_entry_t;
+
+/* Some sanity macros */
+#define CODE_HASH_ENTER(ENTRY) ((ENTRY).enter)
+#define CODE_HASH_LEAVE(ENTRY) ((ENTRY).leave)