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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>
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4 changed files with 21 additions and 3 deletions
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@ -8,8 +8,19 @@
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#include "sysdep/ptrace.h"
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#include "sysdep/ptrace.h"
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/* Copied from kernel.h */
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/* Copied from kernel.h and compiler-gcc.h */
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
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/* Force a compilation error if condition is true, but also produce a
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result (of value 0 and type size_t), so the expression can be used
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e.g. in a structure initializer (or where-ever else comma expressions
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aren't permitted). */
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#define BUILD_BUG_ON_ZERO(e) (sizeof(char[1 - 2 * !!(e)]) - 1)
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/* &a[0] degrades to a pointer: a different type from an array */
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#define __must_be_array(a) \
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BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0])))
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#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
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#define CATCH_EINTR(expr) while ((errno = 0, ((expr) < 0)) && (errno == EINTR))
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#define CATCH_EINTR(expr) while ((errno = 0, ((expr) < 0)) && (errno == EINTR))
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@ -22,6 +22,9 @@
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__asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
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__asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
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(typeof(ptr)) (__ptr + (off)); })
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(typeof(ptr)) (__ptr + (off)); })
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/* &a[0] degrades to a pointer: a different type from an array */
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#define __must_be_array(a) \
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BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0])))
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#define inline inline __attribute__((always_inline))
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#define inline inline __attribute__((always_inline))
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#define __inline__ __inline__ __attribute__((always_inline))
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#define __inline__ __inline__ __attribute__((always_inline))
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@ -21,6 +21,9 @@
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__ptr = (unsigned long) (ptr); \
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__ptr = (unsigned long) (ptr); \
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(typeof(ptr)) (__ptr + (off)); })
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(typeof(ptr)) (__ptr + (off)); })
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/* Intel ECC compiler doesn't support __builtin_types_compatible_p() */
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#define __must_be_array(a) 0
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#endif
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#endif
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#define uninitialized_var(x) x
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#define uninitialized_var(x) x
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@ -35,7 +35,8 @@ extern const char linux_proc_banner[];
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#define ALIGN(x,a) __ALIGN_MASK(x,(typeof(x))(a)-1)
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#define ALIGN(x,a) __ALIGN_MASK(x,(typeof(x))(a)-1)
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#define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
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#define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
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#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
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#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
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#define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f))
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#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
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#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
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#define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y))
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#define roundup(x, y) ((((x) + ((y) - 1)) / (y)) * (y))
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