[COMMITTED] ada: Fix spurious error on 'Input of private type with Type_Invariant aspect

[COMMITTED] ada: Fix spurious error on 'Input of private type with Type_Invariant aspect

[Marc Poulhiès]

From: Eric Botcazou <ebotcazou@adacore.com>

The problem is that it is necessary to break the privacy during the
expansion of the Input attribute, which may introduce a view mismatch
with the parameter of the routine checking the invariant of the type.

gcc/ada/

	* exp_util.adb (Make_Invariant_Call): Convert the expression to
	the type of the formal parameter if need be.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/exp_util.adb | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/gcc/ada/exp_util.adb b/gcc/ada/exp_util.adb
index 9f843d6d71e..a4b5ec366f3 100644
--- a/gcc/ada/exp_util.adb
+++ b/gcc/ada/exp_util.adb
@@ -9928,11 +9928,16 @@ package body Exp_Util is
    -------------------------
 
    function Make_Invariant_Call (Expr : Node_Id) return Node_Id is
-      Loc : constant Source_Ptr := Sloc (Expr);
-      Typ : constant Entity_Id  := Base_Type (Etype (Expr));
+      Loc      : constant Source_Ptr := Sloc (Expr);
+      Typ      : constant Entity_Id  := Base_Type (Etype (Expr));
       pragma Assert (Has_Invariants (Typ));
-      Proc_Id : constant Entity_Id := Invariant_Procedure (Typ);
+      Proc_Id  : constant Entity_Id := Invariant_Procedure (Typ);
       pragma Assert (Present (Proc_Id));
+      Inv_Typ  : constant Entity_Id
+                   := Base_Type (Etype (First_Formal (Proc_Id)));
+
+      Arg : Node_Id;
+
    begin
       --  The invariant procedure has a null body if assertions are disabled or
       --  Assertion_Policy Ignore is in effect. In that case, generate a null
@@ -9940,11 +9945,21 @@ package body Exp_Util is
 
       if Has_Null_Body (Proc_Id) then
          return Make_Null_Statement (Loc);
+
       else
+         --  As done elsewhere, for example in Build_Initialization_Call, we
+         --  may need to bridge the gap between views of the type.
+
+         if Inv_Typ /= Typ then
+            Arg := OK_Convert_To (Inv_Typ, Expr);
+         else
+            Arg := Relocate_Node (Expr);
+         end if;
+
          return
            Make_Procedure_Call_Statement (Loc,
              Name                   => New_Occurrence_Of (Proc_Id, Loc),
-             Parameter_Associations => New_List (Relocate_Node (Expr)));
+             Parameter_Associations => New_List (Arg));
       end if;
    end Make_Invariant_Call;
 
-- 
2.40.0