Re: [PATCH] Do not expand macros to 'defined'

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2019-01-16 01:34, Павел Крюков wrote:
> Expanding a macro which contains 'defined' PP keyword is UB.
> 
> sim/common/Changelog:
> 2019-01-16  Pavel I. Kryukov  <kryukov@frtk.ru>
> 
>         * sim-arange.c: eliminate DEFINE_NON_INLINE_P
> ---
>  sim/common/sim-arange.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/sim/common/sim-arange.c b/sim/common/sim-arange.c
> index 6373b742ce8..b3488ab564a 100644
> --- a/sim/common/sim-arange.c
> +++ b/sim/common/sim-arange.c
> @@ -32,10 +32,7 @@ along with this program.  If not, see
> <http://www.gnu.org/licenses/>.  */
>  #include <string.h>
>  #endif
> 
> -#define DEFINE_INLINE_P (! defined (SIM_ARANGE_C_INCLUDED))
> -#define DEFINE_NON_INLINE_P defined (SIM_ARANGE_C_INCLUDED)
> -
> -#if DEFINE_NON_INLINE_P
> +#ifdef SIM_ARANGE_C_INCLUDED
> 
>  /* Insert a range.  */
> 
> @@ -280,9 +277,7 @@ sim_addr_range_delete (ADDR_RANGE *ar,
> address_word start, address_word end)
>    build_search_tree (ar);
>  }
> 
> -#endif /* DEFINE_NON_INLINE_P */
> -
> -#if DEFINE_INLINE_P
> +#else /* SIM_ARANGE_C_INCLUDED */
> 
>  SIM_ARANGE_INLINE int
>  sim_addr_range_hit_p (ADDR_RANGE *ar, address_word addr)
> @@ -301,4 +296,4 @@ sim_addr_range_hit_p (ADDR_RANGE *ar, address_word 
> addr)
>    return 0;
>  }
> 
> -#endif /* DEFINE_INLINE_P */
> +#endif /* SIM_ARANGE_C_INCLUDED */

The patch LGTM, I agree these macros are not really needed.  But I am 
confused, does this actually fix your c++ build?  You mentioned you were 
using g++ (and therefore cpp), which supposedly can handle this fine:

https://gcc.gnu.org/onlinedocs/cpp/Defined.html

If so, what did the error look like?

Simon