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62 lines
2.1 KiB
62 lines
2.1 KiB
From b86fec9baa9c2ee03b28cfc8dad95c41bf9acaad Mon Sep 17 00:00:00 2001 |
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From: Flavio Leitner <fbl@redhat.com> |
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Date: Wed, 2 Oct 2013 02:40:09 -0300 |
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Subject: [PATCH] util: use gcc builtins to better check array sizes |
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GCC provides two useful builtin functions that can help |
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to improve array size checking during compilation. |
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This patch contains no functional changes, but it makes |
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it easier to detect mistakes. |
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Signed-off-by: Flavio Leitner <fbl@redhat.com> |
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Signed-off-by: Ben Pfaff <blp@nicira.com> |
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--- |
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AUTHORS | 1 + |
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lib/util.h | 17 ++++++++++++++++- |
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2 files changed, 17 insertions(+), 1 deletion(-) |
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diff --git a/AUTHORS b/AUTHORS |
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index af34bfe..7a919a2 100644 |
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--- a/AUTHORS |
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+++ b/AUTHORS |
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@@ -32,6 +32,7 @@ Duffie Cooley dcooley@nicira.com |
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Ed Maste emaste at freebsd.org |
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Edward Tomasz Napierała trasz@freebsd.org |
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Ethan Jackson ethan@nicira.com |
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+Flavio Leitner fbl@redhat.com |
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FUJITA Tomonori fujita.tomonori@lab.ntt.co.jp |
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Gaetano Catalli gaetano.catalli@gmail.com |
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Giuseppe Lettieri g.lettieri@iet.unipi.it |
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diff --git a/lib/util.h b/lib/util.h |
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index 0db41be..a899065 100644 |
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--- a/lib/util.h |
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+++ b/lib/util.h |
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@@ -87,8 +87,23 @@ void ovs_assert_failure(const char *, const char *, const char *) NO_RETURN; |
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extern const char *program_name; |
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+#define __ARRAY_SIZE_NOCHECK(ARRAY) (sizeof(ARRAY) / sizeof((ARRAY)[0])) |
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+#ifdef __GNUC__ |
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+/* return 0 for array types, 1 otherwise */ |
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+#define __ARRAY_CHECK(ARRAY) \ |
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+ !__builtin_types_compatible_p(typeof(ARRAY), typeof(&ARRAY[0])) |
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+ |
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+/* compile-time fail if not array */ |
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+#define __ARRAY_FAIL(ARRAY) (sizeof(char[-2*!__ARRAY_CHECK(ARRAY)])) |
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+#define __ARRAY_SIZE(ARRAY) \ |
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+ __builtin_choose_expr(__ARRAY_CHECK(ARRAY), \ |
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+ __ARRAY_SIZE_NOCHECK(ARRAY), __ARRAY_FAIL(ARRAY)) |
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+#else |
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+#define __ARRAY_SIZE(ARRAY) __ARRAY_SIZE_NOCHECK(ARRAY) |
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+#endif |
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+ |
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/* Returns the number of elements in ARRAY. */ |
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-#define ARRAY_SIZE(ARRAY) (sizeof ARRAY / sizeof *ARRAY) |
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+#define ARRAY_SIZE(ARRAY) __ARRAY_SIZE(ARRAY) |
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/* Returns X / Y, rounding up. X must be nonnegative to round correctly. */ |
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#define DIV_ROUND_UP(X, Y) (((X) + ((Y) - 1)) / (Y)) |
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-- |
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1.8.4.2 |
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