From fe81e1f9751cca8de33c3c45f6fc181c626c57f0 Mon Sep 17 00:00:00 2001 From: Brian Paul Date: Wed, 15 Nov 2017 16:17:44 -0700 Subject: [PATCH] util: add new ASSERT_BITFIELD_SIZE() macro (v3) For checking that bitfields are large enough to hold the largest expected value. v2: move into existing util/macros.h header where STATIC_ASSERT() lives. v3: add MAYBE_UNUSED to variable declaration Reviewed-by: Ian Romanick --- src/util/macros.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/src/util/macros.h b/src/util/macros.h index a9a52a1a478..aa36253217c 100644 --- a/src/util/macros.h +++ b/src/util/macros.h @@ -241,6 +241,23 @@ do { \ #define ATTRIBUTE_NOINLINE #endif + +/** + * Check that STRUCT::FIELD can hold MAXVAL. We use a lot of bitfields + * in Mesa/gallium. We have to be sure they're of sufficient size to + * hold the largest expected value. + * Note that with MSVC, enums are signed and enum bitfields need one extra + * high bit (always zero) to ensure the max value is handled correctly. + * This macro will detect that with MSVC, but not GCC. + */ +#define ASSERT_BITFIELD_SIZE(STRUCT, FIELD, MAXVAL) \ + do { \ + MAYBE_UNUSED STRUCT s; \ + s.FIELD = (MAXVAL); \ + assert((int) s.FIELD == (MAXVAL) && "Insufficient bitfield size!"); \ + } while (0) + + /** Compute ceiling of integer quotient of A divided by B. */ #define DIV_ROUND_UP( A, B ) ( (A) % (B) == 0 ? (A)/(B) : (A)/(B)+1 ) -- 2.30.2