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authorRusty Russell <rusty@rustcorp.com.au>2007-05-06 14:51:05 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-07 12:13:00 -0700
commitc5e631cf65f4d6875efcd571275436f2964a8b48 (patch)
tree1aee9d61560ee369b4a2f077a79e37ab868a4b2d /include
parentf34d9d2dcb7f17b64124841345b23adc0843e7a5 (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')
-rw-r--r--include/linux/compiler-gcc.h3
-rw-r--r--include/linux/compiler-intel.h3
-rw-r--r--include/linux/kernel.h3
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))