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

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                              S E M _ C H 3                               --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 1992-2009, 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 Nlists; use Nlists;

with Types;  use Types;

package Sem_Ch3 is

   procedure Analyze_Component_Declaration         (N : Node_Id);

   procedure Analyze_Incomplete_Type_Decl          (N : Node_Id);

   procedure Analyze_Itype_Reference               (N : Node_Id);

   procedure Analyze_Number_Declaration            (N : Node_Id);

   procedure Analyze_Object_Declaration            (N : Node_Id);

   procedure Analyze_Others_Choice                 (N : Node_Id);

   procedure Analyze_Private_Extension_Declaration (N : Node_Id);

   procedure Analyze_Subtype_Indication            (N : Node_Id);

   procedure Analyze_Type_Declaration              (N : Node_Id);

   procedure Analyze_Variant_Part                  (N : Node_Id);

   procedure Analyze_Subtype_Declaration

     (N    : Node_Id;

      Skip : Boolean := False);

   --  Called to analyze a subtype declaration. The parameter Skip is used for

   --  Ada 2005 (AI-412). We set to True in order to avoid reentering the

   --  defining identifier of N when analyzing a rewritten incomplete subtype

   --  declaration.

   function Access_Definition

     (Related_Nod : Node_Id;

      N           : Node_Id) return Entity_Id;

   --  An access definition defines a general access type for a formal

   --  parameter. The procedure is called when processing formals, when

   --  the current scope is the subprogram. The Implicit type is attached

   --  to the Related_Nod put into the enclosing scope, so that the only

   --  entities defined in the spec are the formals themselves.

   procedure Access_Subprogram_Declaration

     (T_Name : Entity_Id;

      T_Def  : Node_Id);

   --  The subprogram specification yields the signature of an implicit

   --  type, whose Ekind is Access_Subprogram_Type. This implicit type is

   --  the designated type of the declared access type. In subprogram calls,

   --  the signature of the implicit type works like the profile of a regular

   --  subprogram.

   procedure Add_Internal_Interface_Entities (Tagged_Type : Entity_Id);

   --  Add to the list of primitives of Tagged_Type the internal entities

   --  associated with covered interface primitives. These entities link the

   --  interface primitives with the tagged type primitives that cover them.

   procedure Analyze_Declarations (L : List_Id);

   --  Called to analyze a list of declarations (in what context ???). Also

   --  performs necessary freezing actions (more description needed ???)

   procedure Analyze_Interface_Declaration (T : Entity_Id; Def : Node_Id);

   --  Analyze an interface declaration or a formal interface declaration

   procedure Array_Type_Declaration (T : in out Entity_Id; Def : Node_Id);

   --  Process an array type declaration. If the array is constrained, we

   --  create an implicit parent array type, with the same index types and

   --  component type.

   procedure Access_Type_Declaration (T : Entity_Id; Def : Node_Id);

   --  Process an access type declaration

   procedure Build_Itype_Reference

     (Ityp : Entity_Id;

      Nod  : Node_Id);

   --  Create a reference to an internal type, for use by Gigi. The back-end

   --  elaborates itypes on demand, i.e. when their first use is seen. This

   --  can lead to scope anomalies if the first use is within a scope that is

   --  nested within the scope that contains  the point of definition of the

   --  itype. The Itype_Reference node forces the elaboration of the itype

   --  in the proper scope. The node is inserted after Nod, which is the

   --  enclosing declaration that generated Ityp.

   --

   --  A related mechanism is used during expansion, for itypes created in

   --  branches of conditionals. See Ensure_Defined in exp_util.

   --  Could both mechanisms be merged ???

   procedure Check_Abstract_Overriding (T : Entity_Id);

   --  Check that all abstract subprograms inherited from T's parent type have

   --  been overridden as required, and that nonabstract subprograms have not

   --  been incorrectly overridden with an abstract subprogram.

   procedure Check_Aliased_Component_Types (T : Entity_Id);

   --  Given an array type or record type T, check that if the type is

   --  nonlimited, then the nominal subtype of any components of T that

   --  have discriminants must be constrained.

   procedure Check_Completion (Body_Id : Node_Id := Empty);

   --  At the end of a declarative part, verify that all entities that require

   --  completion have received one. If Body_Id is absent, the error indicating

   --  a missing completion is placed on the declaration that needs completion.

   --  If Body_Id is present, it is the defining identifier of a package body,

   --  and errors are posted on that node, rather than on the declarations that

   --  require completion in the package declaration.

   procedure Derive_Subprogram

     (New_Subp     : in out Entity_Id;

      Parent_Subp  : Entity_Id;

      Derived_Type : Entity_Id;

      Parent_Type  : Entity_Id;

      Actual_Subp  : Entity_Id := Empty);

   --  Derive the subprogram Parent_Subp from Parent_Type, and replace the

   --  subsidiary subtypes with the derived type to build the specification

   --  of the inherited subprogram (returned in New_Subp). For tagged types,

   --  the derived subprogram is aliased to that of the actual (in the

   --  case where Actual_Subp is nonempty) rather than to the corresponding

   --  subprogram of the parent type.

   procedure Derive_Subprograms

     (Parent_Type    : Entity_Id;

      Derived_Type   : Entity_Id;

      Generic_Actual : Entity_Id := Empty);

   --  To complete type derivation, collect/retrieve the primitive operations

   --  of the parent type, and replace the subsidiary subtypes with the derived

   --  type, to build the specs of the inherited ops. For generic actuals, the

   --  mapping of the primitive operations to those of the parent type is also

   --  done by rederiving the operations within the instance. For tagged types,

   --  the derived subprograms are aliased to those of the actual, not those of

   --  the ancestor.

   --

   --  Note: one might expect this to be private to the package body, but there

   --  is one rather unusual usage in package Exp_Dist.

   function Find_Hidden_Interface

     (Src  : Elist_Id;

      Dest : Elist_Id) return Entity_Id;

   --  Ada 2005: Determine whether the interfaces in list Src are all present

   --  in the list Dest. Return the first differing interface, or Empty

   --  otherwise.

   function Find_Type_Of_Subtype_Indic (S : Node_Id) return Entity_Id;

   --  Given a subtype indication S (which is really an N_Subtype_Indication

   --  node or a plain N_Identifier), find the type of the subtype mark.

   function Find_Type_Name (N : Node_Id) return Entity_Id;

   --  Enter the identifier in a type definition, or find the entity already

   --  declared, in the case of the full declaration of an incomplete or

   --  private type.

   function Get_Discriminant_Value

     (Discriminant       : Entity_Id;

      Typ_For_Constraint : Entity_Id;

      Constraint         : Elist_Id) return Node_Id;

   --  ??? MORE DOCUMENTATION

   --  Given a discriminant somewhere in the Typ_For_Constraint tree and a

   --  Constraint, return the value of that discriminant.

   function Is_Null_Extension (T : Entity_Id) return Boolean;

   --  Returns True if the tagged type T has an N_Full_Type_Declaration that

   --  is a null extension, meaning that it has an extension part without any

   --  components and does not have a known discriminant part.

   function Is_Visible_Component (C : Entity_Id) return Boolean;

   --  Determines if a record component C is visible in the present context.

   --  Note that even though component C could appear in the entity chain

   --  of a record type, C may not be visible in the current context. For

   --  instance, C may be a component inherited in the full view of a private

   --  extension which is not visible in the current context.

   procedure Make_Index

     (I            : Node_Id;

      Related_Nod  : Node_Id;

      Related_Id   : Entity_Id := Empty;

      Suffix_Index : Nat := 1);

   --  Process an index that is given in an array declaration, an entry

   --  family declaration or a loop iteration. The index is given by an

   --  index declaration (a 'box'), or by a discrete range. The later can

   --  be the name of a discrete type, or a subtype indication.

   --

   --  Related_Nod is the node where the potential generated implicit types

   --  will be inserted. The 2 last parameters are used for creating the name.

   procedure Make_Class_Wide_Type (T : Entity_Id);

   --  A Class_Wide_Type is created for each tagged type definition. The

   --  attributes of a class-wide type are inherited from those of the type T.

   --  If T is introduced by a private declaration, the corresponding class

   --  wide type is created at the same time, and therefore there is a private

   --  and a full declaration for the class-wide type as well.

   function OK_For_Limited_Init_In_05

     (Typ : Entity_Id;

      Exp : Node_Id) return Boolean;

   --  Presuming Exp is an expression of an inherently limited type Typ,

   --  returns True if the expression is allowed in an initialization context

   --  by the rules of Ada 2005. We use the rule in RM-7.5(2.1/2), "...it is an

   --  aggregate, a function_call, or a parenthesized expression or qualified

   --  expression whose operand is permitted...". Note that in Ada 95 mode,

   --  we sometimes wish to give warnings based on whether the program _would_

   --  be legal in Ada 2005. Note that Exp must already have been resolved,

   --  so we can know whether it's a function call (as opposed to an indexed

   --  component, for example). In the case where Typ is a limited interface's

   --  class-wide type, then the expression is allowed to be of any kind if its

   --  type is a nonlimited descendant of the interface.

   function OK_For_Limited_Init

     (Typ : Entity_Id;

      Exp : Node_Id) return Boolean;

   --  Always False in Ada 95 mode. Equivalent to OK_For_Limited_Init_In_05 in

   --  Ada 2005 mode.

   procedure Preanalyze_Spec_Expression (N : Node_Id; T : Entity_Id);

   --  Default and per object expressions do not freeze their components, and

   --  must be analyzed and resolved accordingly. The analysis is done by

   --  calling the Preanalyze_And_Resolve routine and setting the global

   --  In_Default_Expression flag. See the documentation section entitled

   --  "Handling of Default and Per-Object Expressions" in sem.ads for full

   --  details. N is the expression to be analyzed, T is the expected type.

   procedure Process_Full_View (N : Node_Id; Full_T, Priv_T : Entity_Id);

   --  Process some semantic actions when the full view of a private type is

   --  encountered and analyzed. The first action is to create the full views

   --  of the dependant private subtypes. The second action is to recopy the

   --  primitive operations of the private view (in the tagged case).

   --  N is the N_Full_Type_Declaration node.

   --

   --    Full_T is the full view of the type whose full declaration is in N.

   --

   --    Priv_T is the private view of the type whose full declaration is in N.

   procedure Process_Range_Expr_In_Decl

     (R           : Node_Id;

      T           : Entity_Id;

      Check_List  : List_Id := Empty_List;

      R_Check_Off : Boolean := False);

   --  Process a range expression that appears in a declaration context. The

   --  range is analyzed and resolved with the base type of the given type, and

   --  an appropriate check for expressions in non-static contexts made on the

   --  bounds. R is analyzed and resolved using T, so the caller should if

   --  necessary link R into the tree before the call, and in particular in the

   --  case of a subtype declaration, it is appropriate to set the parent

   --  pointer of R so that the types get properly frozen. Check_List is used

   --  when the subprogram is called from Build_Record_Init_Proc and is used to

   --  return a set of constraint checking statements generated by the Checks

   --  package. R_Check_Off is set to True when the call to Range_Check is to

   --  be skipped.

   function Process_Subtype

     (S           : Node_Id;

      Related_Nod : Node_Id;

      Related_Id  : Entity_Id := Empty;

      Suffix      : Character := ' ') return Entity_Id;

   --  Process a subtype indication S and return corresponding entity.

   --  Related_Nod is the node where the potential generated implicit types

   --  will be inserted. The Related_Id and Suffix parameters are used to

   --  build the associated Implicit type name.

   procedure Process_Discriminants

     (N    : Node_Id;

      Prev : Entity_Id := Empty);

   --  Process the discriminants contained in an N_Full_Type_Declaration or

   --  N_Incomplete_Type_Decl node N. If the declaration is a completion,

   --  Prev is entity on the partial view, on which references are posted.

   function Replace_Anonymous_Access_To_Protected_Subprogram

     (N : Node_Id) return Entity_Id;

   --  Ada 2005 (AI-254): Create and decorate an internal full type declaration

   --  for an anonymous access to protected subprogram. For a record component

   --  declaration, the type is created in the enclosing scope, for an array

   --  type declaration or an object declaration it is simply placed ahead of

   --  this declaration.

   procedure Set_Completion_Referenced (E : Entity_Id);

   --  If E is the completion of a private or incomplete  type declaration,

   --  or the completion of a deferred constant declaration, mark the entity

   --  as referenced. Warnings on unused entities, if needed, go on the

   --  partial view.

end Sem_Ch3;