[m-rev.] for review: enable the use of unboxed 64-bit integers

[Peter Wang]

On Fri, 16 Feb 2018 03:59:46 -0500 (EST), Julien Fischer <jfischer at opturion.com> wrote:
> 
> For review by anyone.
> 
> This replaces part of an earlier uncommitted change.  I don't think
> we actually need to bump the binary grade compatibility number here
> (as I did in th previous version).
> 
> -----------------------------
> 
> Enable the use of unboxed 64-bit integers.
> 
> Enable the use of unboxed 64-bit integers in C grades on 64-bit
> machines.
> 
> Add a new internal grade component corresponding to the use of 64-bit
> integers.
> 
> configure.ac:
>      Test whether we can use unboxed 64-bit integers.
> 
>      Extend the check for whether previously built C files are compatible with
>      configure determined settings to cover whether 64-bit integer are boxed
>      or not.
> 
> scripts/Mercury.config.boostrap.in:
> scripts/Mercury.config.in:
>       Set the compiler flag for unboxed 64-bit integers if configure determines
>       they can be used.
> 
> runtime/mercury_grade.h:
>       Add the "ubi64" grade component
> 

> diff --git a/configure.ac b/configure.ac
> index a47734d..f53b58d 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -2329,11 +2329,28 @@ AC_SUBST(MR_LONG_DOUBLE_IS_64_BIT)
> 
>   #-----------------------------------------------------------------------------#
> 
> -# XXX INT64 -- while we are boostrapping the changes that introduce int64
> -# and uint64, we always box them.  Support for unboxed 64-bit integer types
> -# will be enabled later.
> -
> -AC_DEFINE(MR_BOXED_INT64S)
> +AC_MSG_CHECKING([whether we can use unboxed 64-bit integers])
> +AC_CACHE_VAL([mercury_cv_unboxed_int64s],
> +    AC_TRY_RUN([

Run-time tests don't work when cross compiling. We should be able to use
a compile-time test, e.g. the trick in MR_STATIC_ASSERT.

> +    #include <stdint.h>
> +    int main() {
> +        if (sizeof(uint64_t) == sizeof(void *))
> +            exit(0);
> +        else
> +            exit(1);
> +        }],
> +        [mercury_cv_unboxed_int64s=yes],
> +        [mercury_cv_unboxed_int64s=no],
> +        [mercury_cv_unboxed_int64s=no])
> +)
> +AC_MSG_RESULT($mercury_cv_unbxed_int64s)

unboxed

> +if test "$mercury_cv_unboxed_int64s" = yes; then
> +    HAVE_BOXED_INT64S="--unboxed-int64s"
> +else
> +    AC_DEFINE(MR_BOXED_INT64S)
> +    HAVE_BOXED_INT64S="--no-unboxed-int64s"
> +fi
> +AC_SUBST([HAVE_BOXED_INT64S])
> 
>   #-----------------------------------------------------------------------------#
> 

Peter