1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- $Revision: 1.16 $ --
11 -- Copyright (C) 1992-1999 Free Software Foundation, Inc. --
13 -- GNAT is free software; you can redistribute it and/or modify it under --
14 -- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
16 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
17 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
18 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
19 -- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNAT; see file COPYING. If not, write --
21 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
22 -- MA 02111-1307, USA. --
24 -- GNAT was originally developed by the GNAT team at New York University. --
25 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
27 ------------------------------------------------------------------------------
29 -- This package contains routines involved in tagged types and dynamic
32 with Types
; use Types
;
35 procedure Check_Controlling_Formals
(Typ
: Entity_Id
; Subp
: Entity_Id
);
36 -- Check that all controlling parameters of Subp are of type Typ,
37 -- that defaults for controlling parameters are tag-indeterminate,
38 -- and that the nominal subtype of the parameters and result
39 -- statically match the first subtype of the controlling type.
41 procedure Check_Dispatching_Call
(N
: Node_Id
);
42 -- Check if a call is a dispatching call. The subprogram is known to
43 -- be a dispatching operation. The call is dispatching if all the
44 -- controlling actuals are dynamically tagged. This procedure is called
45 -- after overload resolution, so the call is known to be unambiguous.
47 procedure Check_Dispatching_Operation
(Subp
, Old_Subp
: Entity_Id
);
48 -- Add "Subp" to the list of primitive operations of the corresponding type
49 -- if it has a parameter of this type and is defined at a proper place for
50 -- primitive operations. (new primitives are only defined in package spec,
51 -- overridden operation can be defined in any scope). If Old_Subp is not
52 -- Empty we are in the overriding case.
54 procedure Check_Operation_From_Incomplete_Type
57 -- If a primitive operation was defined for the incomplete view of the
58 -- type, and the full type declaration is a derived type definition,
59 -- the operation may override an inherited one.
61 procedure Check_Operation_From_Private_View
(Subp
, Old_Subp
: Entity_Id
);
62 -- Add "Old_Subp" to the list of primitive operations of the corresponding
63 -- tagged type if it is the full view of a private tagged type. The Alias
64 -- of "OldSubp" is adjusted to point to the inherited procedure of the
65 -- full view because it is always this one which has to be called.
67 function Find_Controlling_Arg
(N
: Node_Id
) return Node_Id
;
68 -- Returns the actual controlling argument if N is dynamically tagged,
69 -- and Empty if it is not dynamically tagged.
71 function Find_Dispatching_Type
(Subp
: Entity_Id
) return Entity_Id
;
72 -- Check whether a subprogram is dispatching, and find the tagged
73 -- type of the controlling argument or arguments.
75 function Is_Dynamically_Tagged
(N
: Node_Id
) return Boolean;
76 -- Used to determine whether a call is dispatching, i.e. if is an
77 -- an expression of a class_Wide type, or a call to a function with
78 -- controlling result where at least one operand is dynamically tagged.
80 function Is_Tag_Indeterminate
(N
: Node_Id
) return Boolean;
81 -- An expression is tag-indeterminate if it is a call that dispatches
82 -- on result, and all controlling operands are also indeterminate.
83 -- Such a function call may inherit a tag from an enclosing call.
85 procedure Propagate_Tag
(Control
: Node_Id
; Actual
: Node_Id
);
86 -- If a function call is tag-indeterminate, its controlling argument is
87 -- found in the context; either an enclosing call, or the left-hand side
88 -- of the enclosing assignment statement. The tag must be propagated
89 -- recursively to the tag-indeterminate actuals of the call.