1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 -- This package contains routines involved in tagged types and dynamic
29 with Types; use Types;
32 procedure Check_Controlling_Formals (Typ : Entity_Id; Subp : Entity_Id);
33 -- Check that all controlling parameters of Subp are of type Typ,
34 -- that defaults for controlling parameters are tag-indeterminate,
35 -- and that the nominal subtype of the parameters and result
36 -- statically match the first subtype of the controlling type.
38 procedure Check_Dispatching_Call (N : Node_Id);
39 -- Check if a call is a dispatching call. The subprogram is known to
40 -- be a dispatching operation. The call is dispatching if all the
41 -- controlling actuals are dynamically tagged. This procedure is called
42 -- after overload resolution, so the call is known to be unambiguous.
44 procedure Check_Dispatching_Operation (Subp, Old_Subp : Entity_Id);
45 -- Add "Subp" to the list of primitive operations of the corresponding type
46 -- if it has a parameter of this type and is defined at a proper place for
47 -- primitive operations (new primitives are only defined in package spec,
48 -- overridden operation can be defined in any scope). If Old_Subp is not
49 -- Empty we are in the overriding case. If the tagged type associated with
50 -- Subp is a concurrent type (case that occurs when the type is declared in
51 -- a generic because the analysis of generics disables generation of the
52 -- corresponding record) then this routine does does not add "Subp" to the
53 -- list of primitive operations but leaves Subp decorated as dispatching
54 -- operation to enable checks associated with the Object.Operation notation
56 procedure Check_Operation_From_Incomplete_Type
59 -- If a primitive operation was defined for the incomplete view of the
60 -- type, and the full type declaration is a derived type definition,
61 -- the operation may override an inherited one.
63 procedure Check_Operation_From_Private_View (Subp, Old_Subp : Entity_Id);
64 -- Add "Old_Subp" to the list of primitive operations of the corresponding
65 -- tagged type if it is the full view of a private tagged type. The Alias
66 -- of "OldSubp" is adjusted to point to the inherited procedure of the
67 -- full view because it is always this one which has to be called.
69 function Covers_Some_Interface (Prim : Entity_Id) return Boolean;
70 -- Returns true if Prim covers some interface primitive of its associated
71 -- tagged type. The tagged type of Prim must be frozen when this function
74 function Find_Controlling_Arg (N : Node_Id) return Node_Id;
75 -- Returns the actual controlling argument if N is dynamically tagged,
76 -- and Empty if it is not dynamically tagged.
78 function Find_Dispatching_Type (Subp : Entity_Id) return Entity_Id;
79 -- Check whether a subprogram is dispatching, and find the tagged
80 -- type of the controlling argument or arguments.
82 function Find_Primitive_Covering_Interface
83 (Tagged_Type : Entity_Id;
84 Iface_Prim : Entity_Id) return Entity_Id;
85 -- Search in the homonym chain for the primitive of Tagged_Type that
86 -- covers Iface_Prim. The homonym chain traversal is required to catch
87 -- primitives associated with the partial view of private types when
88 -- processing the corresponding full view.
90 function Is_Dynamically_Tagged (N : Node_Id) return Boolean;
91 -- Used to determine whether a call is dispatching, i.e. if is an
92 -- an expression of a class_Wide type, or a call to a function with
93 -- controlling result where at least one operand is dynamically tagged.
95 function Is_Null_Interface_Primitive (E : Entity_Id) return Boolean;
96 -- Returns True if E is a null procedure that is an interface primitive
98 function Is_Tag_Indeterminate (N : Node_Id) return Boolean;
99 -- An expression is tag-indeterminate if it is a call that dispatches
100 -- on result, and all controlling operands are also indeterminate.
101 -- Such a function call may inherit a tag from an enclosing call.
103 procedure Override_Dispatching_Operation
104 (Tagged_Type : Entity_Id;
107 -- Replace an implicit dispatching operation with an explicit one.
108 -- Prev_Op is an inherited primitive operation which is overridden
109 -- by the explicit declaration of New_Op.
111 procedure Propagate_Tag (Control : Node_Id; Actual : Node_Id);
112 -- If a function call is tag-indeterminate, its controlling argument is
113 -- found in the context; either an enclosing call, or the left-hand side
114 -- of the enclosing assignment statement. The tag must be propagated
115 -- recursively to the tag-indeterminate actuals of the call.