1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2023, 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, that
34 -- defaults for controlling parameters are tag-indeterminate, and that the
35 -- nominal subtype of the parameters and result statically match the first
36 -- subtype of the controlling type. Issues appropriate error messages if
37 -- any of these requirements is not met.
39 procedure Check_Dispatching_Call
(N
: Node_Id
);
40 -- Check if the call N is a dispatching call. The subprogram is known to be
41 -- a dispatching operation. The call is dispatching if all the controlling
42 -- actuals are dynamically tagged. This procedure is called after overload
43 -- resolution, so the call is known to be unambiguous.
45 procedure Check_Dispatching_Operation
(Subp
, Old_Subp
: Entity_Id
);
46 -- Add Subp to the list of primitive operations of the corresponding type
47 -- if it has a parameter of this type and is defined at a proper place for
48 -- primitive operations (new primitives are only defined in package spec,
49 -- overridden operation can be defined in any scope). If Old_Subp is not
50 -- Empty we are in the overriding case. If the tagged type associated with
51 -- Subp is a concurrent type (case that occurs when the type is declared
52 -- in a generic because the analysis of generics disables generation of the
53 -- corresponding record) then this routine does not add Subp to the list of
54 -- primitive operations but leaves Subp decorated as dispatching operation
55 -- to enable checks associated with the Object.Operation notation.
57 procedure Check_Operation_From_Incomplete_Type
60 -- If a primitive subprogram Subp was defined for the incomplete view of
61 -- Typ, and the full type declaration is a derived type, then Subp may
62 -- override a subprogram inherited from the parent type. In that case,
63 -- the inherited subprogram will have been hidden by the current one at
64 -- the point of the type derivation, so it does not appear in the list
65 -- of primitive operations of the type, and this procedure inserts the
66 -- overriding subprogram in the full type's list of primitives by
67 -- iterating over the list for the parent type. If instead Subp is a new
68 -- primitive, then it's simply appended to the primitive list.
70 procedure Check_Operation_From_Private_View
(Subp
, Old_Subp
: Entity_Id
);
71 -- No action performed if Subp is not an alias of a dispatching operation.
72 -- Add Old_Subp (if not already present) to the list of primitives of the
73 -- tagged type T of Subp if T is the full view of a private tagged type.
74 -- The Alias of Old_Subp is adjusted to point to the inherited procedure
75 -- of the full view because it is always this one which has to be called.
77 function Covered_Interface_Primitives
(Prim
: Entity_Id
) return Elist_Id
;
78 -- Returns all the interface primitives covered by Prim, when its
79 -- controlling type has progenitors.
81 function Covered_Interface_Op
(Prim
: Entity_Id
) return Entity_Id
;
82 -- Returns the interface primitive that Prim covers, when its controlling
83 -- type has progenitors.
85 function Find_Controlling_Arg
(N
: Node_Id
) return Node_Id
;
86 -- Returns the actual controlling argument if N is dynamically tagged, and
87 -- Empty if it is not dynamically tagged.
89 function Find_Dispatching_Type
(Subp
: Entity_Id
) return Entity_Id
;
90 -- Check whether the subprogram Subp is dispatching, and find the tagged
91 -- type of the controlling argument or arguments. Returns Empty if Subp
92 -- is not a dispatching operation.
94 function Find_Primitive_Covering_Interface
95 (Tagged_Type
: Entity_Id
;
96 Iface_Prim
: Entity_Id
) return Entity_Id
;
97 -- Search the homonym chain for the primitive of Tagged_Type that covers
98 -- Iface_Prim. The homonym chain traversal is required to catch primitives
99 -- associated with the partial view of private types when processing the
100 -- corresponding full view. If the entity is not found, then search for it
101 -- in the list of primitives of Tagged_Type. This latter search is needed
102 -- when the interface primitive is covered by a private subprogram. If the
103 -- primitive has not been covered yet then return the entity that will be
104 -- overridden when the primitive is covered (that is, return the entity
105 -- whose alias attribute references the interface primitive). If none of
106 -- these entities is found then return Empty.
108 type Subprogram_List
is array (Nat
range <>) of Entity_Id
;
109 -- Type returned by Inherited_Subprograms function
112 with function Find_DT
(Subp
: Entity_Id
) return Entity_Id
;
113 package Inheritance_Utilities
is
115 -- This package provides generic versions of inheritance utilities
116 -- provided here. These versions are used in GNATprove backend to adapt
117 -- these utilities to GNATprove specific version of visibility of types.
119 function Inherited_Subprograms
121 No_Interfaces
: Boolean := False;
122 Interfaces_Only
: Boolean := False;
123 One_Only
: Boolean := False) return Subprogram_List
;
125 function Is_Overriding_Subprogram
(E
: Entity_Id
) return Boolean;
126 end Inheritance_Utilities
;
128 function Inherited_Subprograms
130 No_Interfaces
: Boolean := False;
131 Interfaces_Only
: Boolean := False;
132 One_Only
: Boolean := False) return Subprogram_List
;
133 -- Given the spec of a subprogram, this function gathers any inherited
134 -- subprograms from direct inheritance or via interfaces. The result is an
135 -- array of Entity_Ids of the specs of inherited subprograms. Returns a
136 -- null array if passed an Empty spec id. Note that the returned array
137 -- only includes subprograms and generic subprograms (and excludes any
138 -- other inherited entities, in particular enumeration literals). If
139 -- No_Interfaces is True, only return inherited subprograms not coming
140 -- from an interface. If Interfaces_Only is True, only return inherited
141 -- subprograms from interfaces. Otherwise, subprograms inherited directly
142 -- come first, starting with the closest ancestors, and are followed by
143 -- subprograms inherited from interfaces. At most one of No_Interfaces
144 -- and Interfaces_Only should be True.
146 -- If One_Only is set, the search is discontinued as soon as one entry
147 -- is found. In this case the resulting array is either null or contains
148 -- exactly one element.
150 function Is_Dynamically_Tagged
(N
: Node_Id
) return Boolean;
151 -- Used to determine whether a call is dispatching, i.e. if it is
152 -- an expression of a class_Wide type, or a call to a function with
153 -- controlling result where at least one operand is dynamically tagged.
154 -- Also used to determine whether an entity has a class-wide type, or a
155 -- function call that dispatches on the result. Used to verify that all the
156 -- dependent expressions in a conditional expression are equally tagged.
158 function Is_Null_Interface_Primitive
(E
: Entity_Id
) return Boolean;
159 -- Returns True if E is a null procedure that is an interface primitive
161 function Is_Overriding_Subprogram
(E
: Entity_Id
) return Boolean;
162 -- Returns True if E is an overriding subprogram and False otherwise, in
163 -- particular for an inherited subprogram.
165 function Is_Tag_Indeterminate
(N
: Node_Id
) return Boolean;
166 -- Returns true if the expression N is tag-indeterminate. An expression
167 -- is tag-indeterminate if it is a call that dispatches on result, and all
168 -- controlling operands are also indeterminate. Such a function call may
169 -- inherit a tag from an enclosing call.
171 procedure Override_Dispatching_Operation
172 (Tagged_Type
: Entity_Id
;
175 -- Replace an implicit dispatching operation of the type Tagged_Type
176 -- with an explicit one. Prev_Op is an inherited primitive operation which
177 -- is overridden by the explicit declaration of New_Op.
179 procedure Propagate_Tag
(Control
: Node_Id
; Actual
: Node_Id
);
180 -- If a function call given by Actual is tag-indeterminate, its controlling
181 -- argument is found in the context, given by Control: either from an
182 -- operand of an enclosing call, or the left-hand side of the enclosing
183 -- assignment statement. The tag of Control will be propagated recursively
184 -- to Actual and to its tag-indeterminate operands, if any.