1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2012, 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 type of
80 -- the controlling argument or arguments. Returns Empty if Subp is not a
81 -- dispatching operation.
83 function Find_Primitive_Covering_Interface
84 (Tagged_Type : Entity_Id;
85 Iface_Prim : Entity_Id) return Entity_Id;
86 -- Search in the homonym chain for the primitive of Tagged_Type that covers
87 -- Iface_Prim. The homonym chain traversal is required to catch primitives
88 -- associated with the partial view of private types when processing the
89 -- corresponding full view. If the entity is not found then search for it
90 -- in the list of primitives of Tagged_Type. This latter search is needed
91 -- when the interface primitive is covered by a private subprogram. If the
92 -- primitive has not been covered yet then return the entity that will be
93 -- overridden when the primitive is covered (that is, return the entity
94 -- whose alias attribute references the interface primitive). If none of
95 -- these entities is found then return Empty.
97 type Subprogram_List is array (Nat range <>) of Entity_Id;
98 -- Type returned by Inherited_Subprograms function
100 function Inherited_Subprograms (S : Entity_Id) return Subprogram_List;
101 -- Given the spec of a subprogram, this function gathers any inherited
102 -- subprograms from direct inheritance or via interfaces. The list is
103 -- a list of entity id's of the specs of inherited subprograms. Returns
104 -- a null array if passed an Empty spec id. Note that the returned array
105 -- only includes subprograms and generic subprograms (and excludes any
106 -- other inherited entities, in particular enumeration literals).
108 function Is_Dynamically_Tagged (N : Node_Id) return Boolean;
109 -- Used to determine whether a call is dispatching, i.e. if is an
110 -- an expression of a class_Wide type, or a call to a function with
111 -- controlling result where at least one operand is dynamically tagged.
113 function Is_Null_Interface_Primitive (E : Entity_Id) return Boolean;
114 -- Returns True if E is a null procedure that is an interface primitive
116 function Is_Tag_Indeterminate (N : Node_Id) return Boolean;
117 -- An expression is tag-indeterminate if it is a call that dispatches
118 -- on result, and all controlling operands are also indeterminate.
119 -- Such a function call may inherit a tag from an enclosing call.
121 procedure Override_Dispatching_Operation
122 (Tagged_Type : Entity_Id;
125 Is_Wrapper : Boolean := False);
126 -- Replace an implicit dispatching operation with an explicit one.
127 -- Prev_Op is an inherited primitive operation which is overridden
128 -- by the explicit declaration of New_Op. Is_Wrapper is True when
129 -- New_Op is an internally generated wrapper of a controlling function.
131 procedure Propagate_Tag (Control : Node_Id; Actual : Node_Id);
132 -- If a function call is tag-indeterminate, its controlling argument is
133 -- found in the context; either an enclosing call, or the left-hand side
134 -- of the enclosing assignment statement. The tag must be propagated
135 -- recursively to the tag-indeterminate actuals of the call.