[Mesa-dev] [PATCH 1/2] mesa: Define introspection macro to determine whether a type is trivially destructible.

[Ian Romanick]

The minor nit in both patches:  The closing */ of a multiline comment
should go on its own line.

I'd like to hear some feedback from Paul and / or Ken before committing,
but this series is

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

On 10/09/2013 11:20 AM, Francisco Jerez wrote:
> Only implemented on GCC and Clang for now.  Other compilers use a
> dummy implementation that always returns false, which should be a safe
> [but slightly inefficient] assumption in all cases.
> ---
>  src/mesa/main/compiler.h | 23 ++++++++++++++++++++++-
>  1 file changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/src/mesa/main/compiler.h b/src/mesa/main/compiler.h
> index 0f27d5a..8853292 100644
> --- a/src/mesa/main/compiler.h
> +++ b/src/mesa/main/compiler.h
> @@ -444,7 +444,28 @@ do {                                                                    \
>  #define Elements(x) (sizeof(x)/sizeof(*(x)))
>  #endif
>  
> -
> +#ifdef __cplusplus
> +/**
> + * Macro function that evaluates to true if T is a trivially
> + * destructible type -- that is, if its (non-virtual) destructor
> + * performs no action and all member variables and base classes are
> + * trivially destructible themselves.
> + */
> +#   if defined(__GNUC__)
> +#      if ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 3)))
> +#         define HAS_TRIVIAL_DESTRUCTOR(T) __has_trivial_destructor(T)
> +#      endif
> +#   elif (defined(__clang__) && defined(__has_feature))
> +#      if __has_feature(has_trivial_destructor)
> +#         define HAS_TRIVIAL_DESTRUCTOR(T) __has_trivial_destructor(T)
> +#      endif
> +#   endif
> +#   ifndef HAS_TRIVIAL_DESTRUCTOR
> +       /* It's always safe (if inefficient) to assume that a
> +        * destructor is non-trivial */
> +#      define HAS_TRIVIAL_DESTRUCTOR(T) (false)
> +#   endif
> +#endif
>  
>  #ifdef __cplusplus
>  }
>