[Ada] Fix type checking failure with pragma Volatile_Full_Access

[Eric Botcazou]

The problem is that we put an alias set on a variant that is not the main one.

Tested on x86_64-suse-linux, applied on the mainline.


2016-10-10  Eric Botcazou  <ebotca...@adacore.com>

        * gcc-interface/decl.c (gnat_to_gnu_entity): Put volatile qualifier
        on types at the very end of the processing.
        (gnat_to_gnu_param): Remove redundant test.
        (change_qualified_type): Do nothing for unconstrained array types.


2016-10-10  Eric Botcazou  <ebotca...@adacore.com>

        * gnat.dg/specs/vfa.ads: New test.

-- 
Eric Botcazou
Index: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c	(revision 240890)
+++ gcc-interface/decl.c	(working copy)
@@ -4728,14 +4728,6 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
 	      && AGGREGATE_TYPE_P (gnu_type)
 	      && TYPE_BY_REFERENCE_P (gnu_type))
 	    SET_TYPE_MODE (gnu_type, BLKmode);
-
-	  if (Treat_As_Volatile (gnat_entity))
-	    {
-	      const int quals
-		= TYPE_QUAL_VOLATILE
-		  | (Is_Atomic_Or_VFA (gnat_entity) ? TYPE_QUAL_ATOMIC : 0);
-	      gnu_type = change_qualified_type (gnu_type, quals);
-	    }
 	}
 
       /* If this is a derived type, relate its alias set to that of its parent
@@ -4816,6 +4808,14 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
 			     ? ALIAS_SET_COPY : ALIAS_SET_SUPERSET);
 	}
 
+      if (Treat_As_Volatile (gnat_entity))
+	{
+	  const int quals
+	    = TYPE_QUAL_VOLATILE
+	      | (Is_Atomic_Or_VFA (gnat_entity) ? TYPE_QUAL_ATOMIC : 0);
+	  gnu_type = change_qualified_type (gnu_type, quals);
+	}
+
       if (!gnu_decl)
 	gnu_decl = create_type_decl (gnu_entity_name, gnu_type,
 				     artificial_p, debug_info_p,
@@ -5386,12 +5386,9 @@ gnat_to_gnu_param (Entity_Id gnat_param,
     }
 
   /* If this is a read-only parameter, make a variant of the type that is
-     read-only.  ??? However, if this is an unconstrained array, that type
-     can be very complex, so skip it for now.  Likewise for any other
-     self-referential type.  */
-  if (ro_param
-      && TREE_CODE (gnu_param_type) != UNCONSTRAINED_ARRAY_TYPE
-      && !CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_param_type)))
+     read-only.  ??? However, if this is a self-referential type, the type
+     can be very complex, so skip it for now.  */
+  if (ro_param && !CONTAINS_PLACEHOLDER_P (TYPE_SIZE (gnu_param_type)))
     gnu_param_type = change_qualified_type (gnu_param_type, TYPE_QUAL_CONST);
 
   /* For foreign conventions, pass arrays as pointers to the element type.
@@ -6254,6 +6251,10 @@ gnu_ext_name_for_subprog (Entity_Id gnat
 static tree
 change_qualified_type (tree type, int type_quals)
 {
+  /* Qualifiers must be put on the associated array type.  */
+  if (TREE_CODE (type) == UNCONSTRAINED_ARRAY_TYPE)
+    return type;
+
   return build_qualified_type (type, TYPE_QUALS (type) | type_quals);
 }
 

-- { dg-do compile }
-- { dg-options "-g" }

package VFA is

  type Rec is record
    A : Short_Integer;
    B : Short_Integer;
  end record;

  type Rec_VFA is new Rec;
  pragma Volatile_Full_Access (Rec_VFA);

end VFA;