[committed, openmp/openacc] Tweak error message for mapped parameters

[Andrew Stubbs]

On 05/07/2019 15:49, Jakub Jelinek wrote:

OK, here is an alternative patch that merely tries to make the error message
more informative.

Basically, the user needs to get past "it isn't working but I need that
value in this kernel", so hopefully this will help get them there.

WDYT?

I don't like it, I'd end the message where you put ;, the rest doesn't make
sense and will just confuse users.  For one, the compiler should know if the
parameter needs to be copied or not, so doesn't need to talk about
probability thereof, and if it needs to be copied, it should be the compiler
that arranges that (PR90779) and the user has no way to overide or force
that behavior.

Here's what Jakub approved via IRC. Now committed.

Thanks Jakub

Andrew

Tweak error message for mapped parameters.

2019-07-05  Andrew Stubbs  <a...@codesourcery.com>

	gcc/fortran/
	* openmp.c (resolve_omp_clauses): Add custom error messages for
	parameters in map clauses.

diff --git a/gcc/fortran/openmp.c b/gcc/fortran/openmp.c
index 1c7bce6c300..44fcb9db8c6 100644
--- a/gcc/fortran/openmp.c
+++ b/gcc/fortran/openmp.c
@@ -4208,8 +4208,21 @@ resolve_omp_clauses (gfc_code *code, gfc_omp_clauses *omp_clauses,
 		  continue;
 	      }
 	  }
-	gfc_error ("Object %qs is not a variable at %L", n->sym->name,
-		   &n->where);
+	if (list == OMP_LIST_MAP
+	    && n->sym->attr.flavor == FL_PARAMETER)
+	  {
+	    if (openacc)
+	      gfc_error ("Object %qs is not a variable at %L; parameters"
+			 " cannot be and need not be copied", n->sym->name,
+			 &n->where);
+	    else
+	      gfc_error ("Object %qs is not a variable at %L; parameters"
+			 " cannot be and need not be mapped", n->sym->name,
+			 &n->where);
+	  }
+	else
+	  gfc_error ("Object %qs is not a variable at %L", n->sym->name,
+		     &n->where);
       }
 
   for (list = 0; list < OMP_LIST_NUM; list++)