------------------------------------------------------------------------------
--                                                                          --
--                 ASIS-for-GNAT IMPLEMENTATION COMPONENTS                  --
--                                                                          --
--                             A 4 G . A _ S E M                            --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--                            $Revision: 1.16 $
--                                                                          --
--            Copyright (c) 1995-2002, Free Software Foundation, Inc.       --
--                                                                          --
-- ASIS-for-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 --
-- Software Foundation;  either version 2,  or  (at your option)  any later --
-- version. ASIS-for-GNAT is distributed  in the hope  that it will be use- --
-- ful, but WITHOUT ANY WARRANTY; without even the implied warranty of MER- --
-- CHANTABILITY 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 ASIS-for-GNAT; see file     --
-- COPYING. If not, write to the Free Software Foundation,  59 Temple Place --
-- - Suite 330,  Boston, MA 02111-1307, USA.                                --
--                                                                          --
-- As a special exception,  if other files  instantiate  generics from this --
-- unit, or you link  this unit with other files  to produce an executable, --
-- this  unit  does not  by itself cause  the resulting  executable  to  be --
-- covered  by the  GNU  General  Public  License.  This exception does not --
-- however invalidate  any other reasons why  the executable file  might be --
-- covered by the  GNU Public License.                                      --
--                                                                          --
-- ASIS-for-GNAT was originally developed  by the ASIS-for-GNAT team at the --
-- Software  Engineering  Laboratory  of  the Swiss  Federal  Institute  of --
-- Technology (LGL-EPFL) in Lausanne,  Switzerland, in cooperation with the --
-- Scientific  Research  Computer  Center of  Moscow State University (SRCC --
-- MSU), Russia,  with funding partially provided  by grants from the Swiss --
-- National  Science  Foundation  and  the  Swiss  Academy  of  Engineering --
-- Sciences.  ASIS-for-GNAT is now maintained by  Ada Core Technologies Inc --
-- (http://www.gnat.com).                                                   --
--                                                                          --
------------------------------------------------------------------------------

--  This package contains routines needed for semantic queries from
--  more then one Asis package

with Asis;  use Asis;

with Types; use Types;

package A4G.A_Sem is

   --  All the routines defined in this package do not check their
   --  arguments - a caller is responsible for the proper use of these
   --  routines

   function Defined_In_Standard (N : Node_Id) return Boolean;
   --  checks if its argument is an identifier or an enumeration literal
   --  defined in the predefined Standard package

   function Char_Defined_In_Standard (N : Node_Id) return Boolean;
   --  checks if its argument is a character literal defined in the
   --  predefined Standard package

   function Unwind_Renaming (Def_Name : Node_Id) return Node_Id;
   --  Supposing that Def_Name is the node representing some defining
   --  occurrence of some name, this function unwinds all the renamings
   --  (if any) and returns the node representing the defining
   --  name of the entity referenced by this name. If there is no
   --  declaration for a given entity (this is the case, when a name
   --  renames a subprogram-attribute) an Empty node is returned.
   --
   --  Note, that the node for renaming declaration may be rewritten,
   --  in particular, renaming of a subprogram-attribute is rewritten
   --  into a subprogram body

   procedure Set_Stub_For_Subunit_If_Any (Def_Name : in out Node_Id);
   --  If Def_Name is N_Defining_Identifier node which represents the
   --  subprogram defining identifier from the proper body of a subunit,
   --  it is reset to point to the corresponding N_Defining_Identifier
   --  node from the corresponding body stub, if this stub acts as spec,
   --  or to the N_Defining_Identifier node from the corresponding
   --  subprogram declaration. Otherwise the argument remains unchanged.

   function Corr_Decl_For_Stub (Stub_Node : Node_Id) return Node_Id;
   --  This function should be called only for N_Subprogram_Body_Stub
   --  nodes. If the corresponding subprogram body stub is a completion
   --  of some subprogram declaration, the functions returns the node
   --  representing this subprogram declaration, otherwise it returns
   --  the Empty node.

   function Get_Corr_Called_Entity
     (Call : Asis.Element)
      return Asis.Declaration;
   --  This function incapsulates the common code from
   --  Asis.Expressions.Corresponding_Called_Function and
   --  Asis.Statements.Corresponding_Called_Entity.
   --  It gets the Ada construction which is either a procedure (entry)
   --  or a function call and returns the declaration of the called
   --  entity. This function does not check this argument to be an
   --  appropriate Element for any of these ASIS queries.

   function Is_Predefined (Def_Op : Node_Id) return Boolean;
   --  Returns True if Def_Op is N_Defining_Operator_Symbol representing
   --  a predefined operation. Returns False otherwise.
   --  ??? May be, there is something like this in GNAT???

   function Is_From_Instance (Node : Node_Id) return Boolean;
   --  Checks if Node is from expanded generic template

   function Is_From_Unknown_Pragma (Node : Node_Id) return Boolean;
   --  Checks if Node belongs to a subtree rooted  by unknown pragma. The tree
   --  structures for unknown pragmas are very poorly decorated, so semantic
   --  queries may just blow up when applied to elements representing
   --  components of such pragmas.

   procedure Reset_For_Body
     (El        : in out Asis.Element;
      Body_Unit : Asis.Compilation_Unit);
   --  Provided that El is a declaration from the spec of a library package
   --  or a library generic package, this procedure resets El to Is_Identical
   --  Element, but obtained from the tree contained the body for this package.
   --  This body is represented by the Body_Unit parameter, we use it to avoid
   --  call to Asis.Compilation_Units.Corresponding_Body in the implementation
   --  of this function.

   function Get_Actual_Type_Name (Type_Mark_Node : Node_Id) return Node_Id;
   --  This function supposes, that its argument is of N_Identifier kind.
   --  When applied to a reference to an implicit subtype created in
   --  expanded generic instantiation as a way to pass the actual type,
   --  this function "unwinds" this implicit subtyping and returns the
   --  reference to the actual type. Otherwise it returns its argument
   --  unchanged.
   --  The case when the actual type is a derived type is treated specially -
   --  in this case "unwinding" could bring the internal type created by the
   --  front-end, so we break this unwinding and return the entity (!!!) node
   --  of the corresponding actual type.

   function Get_Instance_Name (Int_Name : Node_Id) return Node_Id;
   --  For Int_Node which should be Is_Generic_Instance (otherwise it is an
   --  error to use this function) and which denotes the entity declared in
   --  an artificial package created by the compiler for a generic
   --  instantiation, it finds an entity defined in a generic instantiation

   function Get_Derived_Type
     (Type_Entity     : Entity_Id;
      Inherited_Subpr : Entity_Id)
      return            Entity_Id;
   --  This function supposes that Type_Entity is a type entity,
   --  and Inherited_Subpr is the defining name of implicit inherited
   --  subprogram. It checks if Type_Entity is an ancestor type for the
   --  derived type which inherits Inherited_Subpr, and if it is, returns
   --  the entity of the derived type, otherwise returns Type_Entity

   function Is_Derived_Rep_Item
     (Type_Entity : Entity_Id;
      Rep_Item :    Node_Id)
      return        Boolean;
   --  Supposing that Type_Entity is an entity of some type, and Rep_Item
   --  represents  some representation item from the chain of representation
   --  items associated with this type, this function checks it Type_Entity
   --  derives this Rep_Item from some of its parent types.

end A4G.A_Sem;
