more accurate error messages omp in fortran

[Cesar Philippidis]

(was "Re: more accurate omp in fortran"

Ping.

Cesar

On 10/22/2015 08:21 AM, Cesar Philippidis wrote:
> Currently, for certain omp and oacc errors the fortran will inaccurately
> report exactly where in the omp/acc construct the error has occurred. E.g.
> 
>    !$acc parallel copy (i) copy (i) copy (j)
>                                            1
> Error: Symbol ‘i’ present on multiple clauses at (1)
> 
> instead of
> 
>    !$acc parallel copy (i) copy (i) copy (j)
>                                 1
> Error: Symbol ‘i’ present on multiple clauses at (1)
> 
> The problem here is how the front end uses the locus for the construct
> and not the individual clause. As a result that diagnostic pointer
> points to the end of the construct.
> 
> This patch teaches gfc_resolve_omp_clauses how to use the locus of each
> individual clause instead of the construct when reporting errors
> involving OMP_LIST_ clauses (which are typically clauses involving
> variables). It's still not perfect, but it does improve the quality of
> the error reporting a little. In particular, in openacc, other compilers
> are somewhat lenient in allowing variables to appear in multiple
> clauses, e.g. copyin (foo) copyout (foo), but this is clearly forbidden
> by the spec. I received some bug reports complaining that gfortran's
> errors aren't accurate.
> 
> I've also split off the check for variables appearing in multiple
> clauses into a separate function. It's a little overkill for trunk right
> now, but it is used quite a bit in gomp4 for oacc declare.
> 
> I've tested these changes on x86_64. Is this ok for trunk?
> 
> Cesar
> 
>