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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                             S E M _ S M E M                              --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1998-2008, Free Software Foundation, Inc.         --

--                                                                          --

-- GNAT is free software;  you can  redistribute it  and/or modify it under --

-- terms of the  GNU General Public License as published  by the Free Soft- --

-- ware  Foundation;  either version 3,  or (at your option) any later ver- --

-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --

-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --

-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --

-- for  more details.  You should have  received  a copy of the GNU General --

-- Public License  distributed with GNAT; see file COPYING3.  If not, go to --

-- http://www.gnu.org/licenses for a complete copy of the license.          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

with Atree;   use Atree;

with Einfo;   use Einfo;

with Errout;  use Errout;

with Namet;   use Namet;

with Sem_Aux; use Sem_Aux;

with Sinfo;   use Sinfo;

with Snames;  use Snames;

package body Sem_Smem is

   function Contains_Access_Type (T : Entity_Id) return Boolean;

   --  This function determines if type T is an access type, or contains

   --  a component (array, record, protected type cases) that contains

   --  an access type (recursively defined in the appropriate manner).

   ----------------------

   -- Check_Shared_Var --

   ----------------------

   procedure Check_Shared_Var

     (Id : Entity_Id;

      T  : Entity_Id;

      N  : Node_Id)

   is

   begin

      --  We cannot tolerate aliased variables, because they might be

      --  modified via an aliased pointer, and we could not detect that

      --  this was happening (to update the corresponding shared memory

      --  file), so we must disallow all use of Aliased

      if Aliased_Present (N) then

         Error_Msg_N

           ("aliased variables " &

            "not supported in Shared_Passive partitions",

            N);

      --  We can't support access types at all, since they are local

      --  pointers that cannot in any simple way be transmitted to other

      --  partitions.

      elsif Is_Access_Type (T) then

         Error_Msg_N

           ("access type variables " &

            "not supported in Shared_Passive partitions",

            Id);

      --  We cannot tolerate types that contain access types, same reasons

      elsif Contains_Access_Type (T) then

         Error_Msg_N

           ("types containing access components " &

            "not supported in Shared_Passive partitions",

            Id);

      --  Objects with default-initialized types will be rejected when

      --  the initialization code is generated. However we must flag tasks

      --  earlier on, to prevent expansion of stream attributes that is

      --  bound to fail.

      elsif Has_Task (T) then

         Error_Msg_N

           ("Shared_Passive partitions cannot contain tasks", Id);

      --  Currently we do not support unconstrained record types, since we

      --  use 'Write to write out values. This could probably be special

      --  cased and handled in the future if necessary.

      elsif Is_Record_Type (T)

        and then not Is_Constrained (T)

      then

         Error_Msg_N

           ("unconstrained variant records " &

            "not supported in Shared_Passive partitions",

            Id);

      end if;

   end Check_Shared_Var;

   --------------------------

   -- Contains_Access_Type --

   --------------------------

   function Contains_Access_Type (T : Entity_Id) return Boolean is

      C : Entity_Id;

   begin

      if Is_Access_Type (T) then

         return True;

      elsif Is_Array_Type (T) then

         return Contains_Access_Type (Component_Type (T));

      elsif Is_Record_Type (T) then

         if Has_Discriminants (T) then

            C := First_Discriminant (T);

            while Present (C) loop

               if Comes_From_Source (C) then

                  return True;

               else

                  C := Next_Discriminant (C);

               end if;

            end loop;

         end if;

         C := First_Component (T);

         while Present (C) loop

            --  For components, ignore internal components other than _Parent

            if Comes_From_Source (T)

              and then

                (Chars (C) = Name_uParent

                  or else

                 not Is_Internal_Name (Chars (C)))

              and then Contains_Access_Type (Etype (C))

            then

               return True;

            else

               C := Next_Component (C);

            end if;

         end loop;

         return False;

      elsif Is_Protected_Type (T) then

         return Contains_Access_Type (Corresponding_Record_Type (T));

      else

         return False;

      end if;

   end Contains_Access_Type;

end Sem_Smem;