It's a familiar pattern: some code uses ARRAY_SIZE, then refactoring
changes the argument from an array to a pointer to a dynamically
allocated buffer. Code keeps compiling but any ARRAY_SIZE calls now
return the size of the pointer divided by element size.
Let's add build time checks to ARRAY_SIZE before we allow more
of these in the code-base.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
#endif
+/*
+ * &(x)[0] is always a pointer - if it's same type as x then the argument is a
+ * pointer, not an array.
+ */
+#define QEMU_IS_ARRAY(x) (!__builtin_types_compatible_p(typeof(x), \
+ typeof(&(x)[0])))
#ifndef ARRAY_SIZE
-#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#define ARRAY_SIZE(x) ((sizeof(x) / sizeof((x)[0])) + \
+ QEMU_BUILD_BUG_ON_ZERO(!QEMU_IS_ARRAY(x)))
#endif
int qemu_daemon(int nochdir, int noclose);