[Mesa-dev] [PATCH] util/u_atomic: use STATIC_ASSERT() when selecting the appropriate function
Francisco Jerez
currojerez at riseup.net
Wed May 13 12:18:38 PDT 2015
Emil Velikov <emil.l.velikov at gmail.com> writes:
> As we evaluate sizeof() at compile time, having the run-time assert()
> does not provide any benefits. Move to the compile-time version
> STATIC_ASSERT() which will kindly prompt us when this go wrong.
>
This doesn't look right. AFAIK STATIC_ASSERT() is implemented by
expanding to an array type-id of negative size, which is an error
regardless of whether the sizeof expression is evaluated or not: i.e.
"0 ? sizeof(invalid) : ..." is still an error for the same reason that
"0 * sizeof(invalid)" or "(void)sizeof(invalid)" is an error. That and
also that the whole thing is wrapped in a do-while loop you cannot use
as operand of the ternary operator...
> Cc: Matt Turner <mattst88 at gmail.com>
> Signed-off-by: Emil Velikov <emil.l.velikov at gmail.com>
> ---
> src/util/u_atomic.h | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/src/util/u_atomic.h b/src/util/u_atomic.h
> index e38395a..10c0cca 100644
> --- a/src/util/u_atomic.h
> +++ b/src/util/u_atomic.h
> @@ -86,7 +86,7 @@
> #endif
> #include <windows.h>
> #include <intrin.h>
> -#include <assert.h>
> +#include "util/macros.h"
>
> #if _MSC_VER < 1600
>
> @@ -166,7 +166,7 @@ _InterlockedExchangeAdd8(char volatile *addend, char value)
> sizeof *(_v) == sizeof(short) ? _InterlockedIncrement16((short *) (_v)) : \
> sizeof *(_v) == sizeof(long) ? _InterlockedIncrement ((long *) (_v)) : \
> sizeof *(_v) == sizeof(__int64) ? InterlockedIncrement64 ((__int64 *)(_v)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #define p_atomic_dec(_v) \
> ((void) p_atomic_dec_return(_v))
> @@ -175,21 +175,21 @@ _InterlockedExchangeAdd8(char volatile *addend, char value)
> sizeof *(_v) == sizeof(short) ? _InterlockedDecrement16((short *) (_v)) : \
> sizeof *(_v) == sizeof(long) ? _InterlockedDecrement ((long *) (_v)) : \
> sizeof *(_v) == sizeof(__int64) ? InterlockedDecrement64 ((__int64 *)(_v)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #define p_atomic_add(_v, _i) (\
> sizeof *(_v) == sizeof(char) ? _InterlockedExchangeAdd8 ((char *) (_v), (_i)) : \
> sizeof *(_v) == sizeof(short) ? _InterlockedExchangeAdd16((short *) (_v), (_i)) : \
> sizeof *(_v) == sizeof(long) ? _InterlockedExchangeAdd ((long *) (_v), (_i)) : \
> sizeof *(_v) == sizeof(__int64) ? InterlockedExchangeAdd64((__int64 *)(_v), (_i)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #define p_atomic_cmpxchg(_v, _old, _new) (\
> sizeof *(_v) == sizeof(char) ? _InterlockedCompareExchange8 ((char *) (_v), (char) (_new), (char) (_old)) : \
> sizeof *(_v) == sizeof(short) ? _InterlockedCompareExchange16((short *) (_v), (short) (_new), (short) (_old)) : \
> sizeof *(_v) == sizeof(long) ? _InterlockedCompareExchange ((long *) (_v), (long) (_new), (long) (_old)) : \
> sizeof *(_v) == sizeof(__int64) ? InterlockedCompareExchange64 ((__int64 *)(_v), (__int64)(_new), (__int64)(_old)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #endif
>
> @@ -198,7 +198,7 @@ _InterlockedExchangeAdd8(char volatile *addend, char value)
> #define PIPE_ATOMIC "Solaris OS atomic functions"
>
> #include <atomic.h>
> -#include <assert.h>
> +#include "util/macros.h"
>
> #define p_atomic_set(_v, _i) (*(_v) = (_i))
> #define p_atomic_read(_v) (*(_v))
> @@ -208,49 +208,49 @@ _InterlockedExchangeAdd8(char volatile *addend, char value)
> sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) == 0 : \
> sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) == 0 : \
> sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) == 0 : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #define p_atomic_inc(v) (void) (\
> sizeof(*v) == sizeof(uint8_t) ? atomic_inc_8 ((uint8_t *)(v)) : \
> sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16((uint16_t *)(v)) : \
> sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32((uint32_t *)(v)) : \
> sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64((uint64_t *)(v)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #define p_atomic_inc_return(v) ((__typeof(*v)) \
> sizeof(*v) == sizeof(uint8_t) ? atomic_inc_8_nv ((uint8_t *)(v)) : \
> sizeof(*v) == sizeof(uint16_t) ? atomic_inc_16_nv((uint16_t *)(v)) : \
> sizeof(*v) == sizeof(uint32_t) ? atomic_inc_32_nv((uint32_t *)(v)) : \
> sizeof(*v) == sizeof(uint64_t) ? atomic_inc_64_nv((uint64_t *)(v)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #define p_atomic_dec(v) ((void) \
> sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8 ((uint8_t *)(v)) : \
> sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16((uint16_t *)(v)) : \
> sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32((uint32_t *)(v)) : \
> sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64((uint64_t *)(v)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #define p_atomic_dec_return(v) ((__typeof(*v)) \
> sizeof(*v) == sizeof(uint8_t) ? atomic_dec_8_nv ((uint8_t *)(v)) : \
> sizeof(*v) == sizeof(uint16_t) ? atomic_dec_16_nv((uint16_t *)(v)) : \
> sizeof(*v) == sizeof(uint32_t) ? atomic_dec_32_nv((uint32_t *)(v)) : \
> sizeof(*v) == sizeof(uint64_t) ? atomic_dec_64_nv((uint64_t *)(v)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #define p_atomic_add(v, i) ((void) \
> sizeof(*v) == sizeof(uint8_t) ? atomic_add_8 ((uint8_t *)(v), (i)) : \
> sizeof(*v) == sizeof(uint16_t) ? atomic_add_16((uint16_t *)(v), (i)) : \
> sizeof(*v) == sizeof(uint32_t) ? atomic_add_32((uint32_t *)(v), (i)) : \
> sizeof(*v) == sizeof(uint64_t) ? atomic_add_64((uint64_t *)(v), (i)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #define p_atomic_cmpxchg(v, old, _new) ((__typeof(*v)) \
> sizeof(*v) == sizeof(uint8_t) ? atomic_cas_8 ((uint8_t *)(v), (uint8_t )(old), (uint8_t )(_new)) : \
> sizeof(*v) == sizeof(uint16_t) ? atomic_cas_16((uint16_t *)(v), (uint16_t)(old), (uint16_t)(_new)) : \
> sizeof(*v) == sizeof(uint32_t) ? atomic_cas_32((uint32_t *)(v), (uint32_t)(old), (uint32_t)(_new)) : \
> sizeof(*v) == sizeof(uint64_t) ? atomic_cas_64((uint64_t *)(v), (uint64_t)(old), (uint64_t)(_new)) : \
> - (assert(!"should not get here"), 0))
> + (STATIC_ASSERT(!"should not get here"), 0))
>
> #endif
>
> --
> 2.1.3
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
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