exp_ch3.ads   [plain text]


------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                              E X P _ C H 3                               --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--          Copyright (C) 1992-2005, 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 2,  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 COPYING.  If not, write --
-- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
-- Boston, MA 02110-1301, USA.                                              --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

--  Expand routines for chapter 3 constructs

with Types;  use Types;
with Elists; use Elists;
with Uintp;  use Uintp;

package Exp_Ch3 is

   procedure Expand_N_Object_Declaration         (N : Node_Id);
   procedure Expand_N_Subtype_Indication         (N : Node_Id);
   procedure Expand_N_Variant_Part               (N : Node_Id);
   procedure Expand_N_Full_Type_Declaration      (N : Node_Id);

   procedure Expand_Previous_Access_Type (Def_Id : Entity_Id);
   --  For a full type declaration that contains tasks, or that is a task,
   --  check whether there exists an access type whose designated type is an
   --  incomplete declarations for the current composite type. If so, build the
   --  master for that access type, now that it is known to denote an object
   --  with tasks.

   procedure Expand_Record_Extension (T : Entity_Id; Def : Node_Id);
   --  Add a field _parent in the extension part of the record

   procedure Build_Class_Wide_Master (T : Entity_Id);
   --  For access to class-wide limited types we must build a task master
   --  because some subsequent extension may add a task component. To avoid
   --  bringing in the tasking run-time whenever an access-to-class-wide
   --  limited type is used, we use the soft-link mechanism and add a level of
   --  indirection to calls to routines that manipulate Master_Ids. This must
   --  also be used for anonymous access types whose designated type is a task
   --  or synchronized interface.

   procedure Build_Discr_Checking_Funcs (N : Node_Id);
   --  Builds function which checks whether the component name is consistent
   --  with the current discriminants. N is the full type declaration node,
   --  and the discriminant checking functions are inserted after this node.

   function Build_Initialization_Call
     (Loc               : Source_Ptr;
      Id_Ref            : Node_Id;
      Typ               : Entity_Id;
      In_Init_Proc      : Boolean := False;
      Enclos_Type       : Entity_Id := Empty;
      Discr_Map         : Elist_Id := New_Elmt_List;
      With_Default_Init : Boolean := False) return List_Id;
   --  Builds a call to the initialization procedure of the Id entity. Id_Ref
   --  is either a new reference to Id (for record fields), or an indexed
   --  component (for array elements). Loc is the source location for the
   --  constructed tree, and Typ is the type of the entity (the initialization
   --  procedure of the base type is the procedure that actually gets called).
   --  In_Init_Proc has to be set to True when the call is itself in an init
   --  proc in order to enable the use of discriminals. Enclos_type is the type
   --  of the init proc and it is used for various expansion cases including
   --  the case where Typ is a task type which is a array component, the
   --  indices of the enclosing type are used to build the string that
   --  identifies each task at runtime.
   --
   --  Discr_Map is used to replace discriminants by their discriminals in
   --  expressions used to constrain record components. In the presence of
   --  entry families bounded by discriminants, protected type discriminants
   --  can appear within expressions in array bounds (not as stand-alone
   --  identifiers) and a general replacement is necessary.
   --
   --  Ada 2005 (AI-287): With_Default_Init is used to indicate that the
   --  initialization call corresponds to a default initialized component
   --  of an aggregate.

   function Freeze_Type (N : Node_Id) return Boolean;
   --  This function executes the freezing actions associated with the given
   --  freeze type node N and returns True if the node is to be deleted. We
   --  delete the node if it is present just for front end purpose and we don't
   --  want Gigi to see the node. This function can't delete the node itself
   --  since it would confuse any remaining processing of the freeze node.

   function Needs_Simple_Initialization (T : Entity_Id) return Boolean;
   --  Certain types need initialization even though there is no specific
   --  initialization routine. In this category are access types (which need
   --  initializing to null), packed array types whose implementation is a
   --  modular type, and all scalar types if Normalize_Scalars is set, as well
   --  as private types whose underlying type is present and meets any of these
   --  criteria. Finally, descendants of String and Wide_String also need
   --  initialization in Initialize/Normalize_Scalars mode.

   function Get_Simple_Init_Val
     (T    : Entity_Id;
      Loc  : Source_Ptr;
      Size : Uint := No_Uint) return Node_Id;
   --  For a type which Needs_Simple_Initialization (see above), prepares the
   --  tree for an expression representing the required initial value. Loc is
   --  the source location used in constructing this tree which is returned as
   --  the result of the call. The Size parameter indicates the target size of
   --  the object if it is known (indicated by a value that is not No_Uint and
   --  is greater than zero). If Size is not given (Size set to No_Uint, or
   --  non-positive), then the Esize of T is used as an estimate of the Size.
   --  The object size is needed to prepare a known invalid value for use by
   --  Normalize_Scalars.

end Exp_Ch3;