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 <m...@redhat.com> --- include/qemu/osdep.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 689f253..24bfda0 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -199,7 +199,13 @@ extern int daemon(int, int); #endif #ifndef ARRAY_SIZE -#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) +/* + * &(x)[0] is always a pointer - if it's same type as x then the argument is a + * pointer, not an array as expected. + */ +#define ARRAY_SIZE(x) ((sizeof(x) / sizeof((x)[0])) + QEMU_BUILD_BUG_ON_ZERO( \ + __builtin_types_compatible_p(typeof(x), \ + typeof(&(x)[0])))) #endif int qemu_daemon(int nochdir, int noclose); -- MST
