From 71510e531d8874f35d15460eb4c8a99d3ef31869 Mon Sep 17 00:00:00 2001 From: David Lamparter Date: Thu, 14 Sep 2023 11:43:56 +0200 Subject: [PATCH] lib: another attempt at Coverity false positives Typesafe hash tables do this: assume((tabshift) >= 2 && (tabshift) <= 33); (val) >> (33 - (tabshift)); Sadly, Coverity currently ignores assume() and says: [...] right shifting by more than 31 bits has undefined behavior. The shift amount, "33 - h->hh.tabshift", is 33. Let's see if Coverity understands this can't happen... Signed-off-by: David Lamparter --- lib/compiler.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/lib/compiler.h b/lib/compiler.h index 29fcfbefbf..ce6727685f 100644 --- a/lib/compiler.h +++ b/lib/compiler.h @@ -122,6 +122,14 @@ extern "C" { #define assume(x) #endif +#ifdef __COVERITY__ +/* __coverity_panic__() is named a bit poorly, it's essentially the same as + * __builtin_unreachable(). Used to eliminate false positives. + */ +#undef assume +#define assume(x) do { if (!(x)) __coverity_panic__(); } while (0) +#endif + /* for helper functions defined inside macros */ #define macro_inline static inline __attribute__((unused)) #define macro_pure static inline __attribute__((unused, pure)) -- 2.39.5