diff options
| author | Rusty Russell <rusty@rustcorp.com.au> | 2007-05-06 14:51:05 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-07 12:13:00 -0700 |
| commit | c5e631cf65f4d6875efcd571275436f2964a8b48 (patch) | |
| tree | 1aee9d61560ee369b4a2f077a79e37ab868a4b2d /include/linux | |
| parent | f34d9d2dcb7f17b64124841345b23adc0843e7a5 (diff) | |
ARRAY_SIZE: check for type
We can use a gcc extension to ensure that ARRAY_SIZE() is handed an array,
not a pointer. This is especially important when code is changed from a
fixed array to a pointer. I assume the Intel compiler doesn't support
__builtin_types_compatible_p.
[jdike@addtoit.com: uml: update UML definition of ARRAY_SIZE]
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/compiler-gcc.h | 3 | ||||
| -rw-r--r-- | include/linux/compiler-intel.h | 3 | ||||
| -rw-r--r-- | include/linux/kernel.h | 3 |
3 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 9008eabb9c3..a9f794716a8 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -22,6 +22,9 @@ __asm__ ("" : "=r"(__ptr) : "0"(ptr)); \ (typeof(ptr)) (__ptr + (off)); }) +/* &a[0] degrades to a pointer: a different type from an array */ +#define __must_be_array(a) \ + BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0]))) #define inline inline __attribute__((always_inline)) #define __inline__ __inline__ __attribute__((always_inline)) diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h index a436eea4391..b769961e6f2 100644 --- a/include/linux/compiler-intel.h +++ b/include/linux/compiler-intel.h @@ -21,6 +21,9 @@ __ptr = (unsigned long) (ptr); \ (typeof(ptr)) (__ptr + (off)); }) +/* Intel ECC compiler doesn't support __builtin_types_compatible_p() */ +#define __must_be_array(a) 0 + #endif #define uninitialized_var(x) x diff --git a/include/linux/kernel.h b/include/linux/kernel.h index e2f41b051b1..144b615f3a8 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -35,7 +35,8 @@ extern const char linux_proc_banner[]; #define ALIGN(x,a) __ALIGN_MASK(x,(typeof(x))(a)-1) #define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask)) -#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr)) + #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f)) #define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d)) #define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y)) |