[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH v2 4/4] ARRAY_SIZE: check that argument is an array
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] [PATCH v2 4/4] ARRAY_SIZE: check that argument is an array |
Date: |
Wed, 18 Jan 2017 22:55:55 +0200 |
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 <address@hidden>
---
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
- Re: [Qemu-devel] [PATCH v2 2/4] compiler: drop ; after BUILD_BUG_ON, (continued)
- [Qemu-devel] [PATCH v2 3/4] compiler: expression version of QEMU_BUILD_BUG_ON, Michael S. Tsirkin, 2017/01/18
- Re: [Qemu-devel] [PATCH v2 3/4] compiler: expression version of QEMU_BUILD_BUG_ON, Markus Armbruster, 2017/01/19
- Re: [Qemu-devel] [PATCH v2 3/4] compiler: expression version of QEMU_BUILD_BUG_ON, Paolo Bonzini, 2017/01/19
- Re: [Qemu-devel] [PATCH v2 3/4] compiler: expression version of QEMU_BUILD_BUG_ON, Markus Armbruster, 2017/01/19
- Re: [Qemu-devel] [PATCH v2 3/4] compiler: expression version of QEMU_BUILD_BUG_ON, Michael S. Tsirkin, 2017/01/19
- Re: [Qemu-devel] [PATCH v2 3/4] compiler: expression version of QEMU_BUILD_BUG_ON, Eric Blake, 2017/01/19
- Re: [Qemu-devel] [PATCH v2 3/4] compiler: expression version of QEMU_BUILD_BUG_ON, Michael S. Tsirkin, 2017/01/19
- Re: [Qemu-devel] [PATCH v2 3/4] compiler: expression version of QEMU_BUILD_BUG_ON, Michael S. Tsirkin, 2017/01/19
[Qemu-devel] [PATCH v2 4/4] ARRAY_SIZE: check that argument is an array,
Michael S. Tsirkin <=
Re: [Qemu-devel] [PATCH v2 0/4] virtio: ARRAY_SIZE fixups, no-reply, 2017/01/18