1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2019, 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 operation was defined for the incomplete view of the
61 -- type, and the full type declaration is a derived type definition,
62 -- the operation may override an inherited one.
63 -- Need more description here, what are the parameters, and what does
64 -- this call actually do???
66 procedure Check_Operation_From_Private_View
(Subp
, Old_Subp
: Entity_Id
);
67 -- Add Old_Subp to the list of primitive operations of the corresponding
68 -- tagged type if it is the full view of a private tagged type. The Alias
69 -- of Old_Subp is adjusted to point to the inherited procedure of the
70 -- full view because it is always this one which has to be called.
71 -- What is Subp used for???
73 function Covered_Interface_Op
(Prim
: Entity_Id
) return Entity_Id
;
74 -- Returns the interface primitive that Prim covers, when its controlling
75 -- type has progenitors.
77 function Find_Controlling_Arg
(N
: Node_Id
) return Node_Id
;
78 -- Returns the actual controlling argument if N is dynamically tagged, and
79 -- Empty if it is not dynamically tagged.
81 function Find_Dispatching_Type
(Subp
: Entity_Id
) return Entity_Id
;
82 -- Check whether the subprogram Subp is dispatching, and find the tagged
83 -- type of the controlling argument or arguments. Returns Empty if Subp
84 -- is not a dispatching operation.
86 function Find_Primitive_Covering_Interface
87 (Tagged_Type
: Entity_Id
;
88 Iface_Prim
: Entity_Id
) return Entity_Id
;
89 -- Search the homonym chain for the primitive of Tagged_Type that covers
90 -- Iface_Prim. The homonym chain traversal is required to catch primitives
91 -- associated with the partial view of private types when processing the
92 -- corresponding full view. If the entity is not found, then search for it
93 -- in the list of primitives of Tagged_Type. This latter search is needed
94 -- when the interface primitive is covered by a private subprogram. If the
95 -- primitive has not been covered yet then return the entity that will be
96 -- overridden when the primitive is covered (that is, return the entity
97 -- whose alias attribute references the interface primitive). If none of
98 -- these entities is found then return Empty.
100 type Subprogram_List
is array (Nat
range <>) of Entity_Id
;
101 -- Type returned by Inherited_Subprograms function
104 with function Find_DT
(Subp
: Entity_Id
) return Entity_Id
;
105 package Inheritance_Utilities
is
107 -- This package provides generic versions of inheritance utilities
108 -- provided here. These versions are used in GNATprove backend to adapt
109 -- these utilities to GNATprove specific version of visibility of types.
111 function Inherited_Subprograms
113 No_Interfaces
: Boolean := False;
114 Interfaces_Only
: Boolean := False;
115 One_Only
: Boolean := False) return Subprogram_List
;
117 function Is_Overriding_Subprogram
(E
: Entity_Id
) return Boolean;
118 end Inheritance_Utilities
;
120 function Inherited_Subprograms
122 No_Interfaces
: Boolean := False;
123 Interfaces_Only
: Boolean := False;
124 One_Only
: Boolean := False) return Subprogram_List
;
125 -- Given the spec of a subprogram, this function gathers any inherited
126 -- subprograms from direct inheritance or via interfaces. The result is an
127 -- array of Entity_Ids of the specs of inherited subprograms. Returns a
128 -- null array if passed an Empty spec id. Note that the returned array
129 -- only includes subprograms and generic subprograms (and excludes any
130 -- other inherited entities, in particular enumeration literals). If
131 -- No_Interfaces is True, only return inherited subprograms not coming
132 -- from an interface. If Interfaces_Only is True, only return inherited
133 -- subprograms from interfaces. Otherwise, subprograms inherited directly
134 -- come first, starting with the closest ancestors, and are followed by
135 -- subprograms inherited from interfaces. At most one of No_Interfaces
136 -- and Interfaces_Only should be True.
138 -- If One_Only is set, the search is discontinued as soon as one entry
139 -- is found. In this case the resulting array is either null or contains
140 -- exactly one element.
142 function Is_Dynamically_Tagged
(N
: Node_Id
) return Boolean;
143 -- Used to determine whether a call is dispatching, i.e. if it is
144 -- an expression of a class_Wide type, or a call to a function with
145 -- controlling result where at least one operand is dynamically tagged.
146 -- Also used to determine whether an entity has a class-wide type, or a
147 -- function call that dispatches on the result. Used to verify that all the
148 -- dependent expressions in a conditional expression are equally tagged.
150 function Is_Null_Interface_Primitive
(E
: Entity_Id
) return Boolean;
151 -- Returns True if E is a null procedure that is an interface primitive
153 function Is_Overriding_Subprogram
(E
: Entity_Id
) return Boolean;
154 -- Returns True if E is an overriding subprogram
156 function Is_Tag_Indeterminate
(N
: Node_Id
) return Boolean;
157 -- Returns true if the expression N is tag-indeterminate. An expression
158 -- is tag-indeterminate if it is a call that dispatches on result, and all
159 -- controlling operands are also indeterminate. Such a function call may
160 -- inherit a tag from an enclosing call.
162 procedure Override_Dispatching_Operation
163 (Tagged_Type
: Entity_Id
;
166 Is_Wrapper
: Boolean := False);
167 -- Replace an implicit dispatching operation of the type Tagged_Type
168 -- with an explicit one. Prev_Op is an inherited primitive operation which
169 -- is overridden by the explicit declaration of New_Op. Is_Wrapper is
170 -- True when New_Op is an internally generated wrapper of a controlling
171 -- function. The caller checks that Tagged_Type is indeed a tagged type.
173 procedure Propagate_Tag
(Control
: Node_Id
; Actual
: Node_Id
);
174 -- If a function call is tag-indeterminate, its controlling argument is
175 -- found in the context: either an enclosing call, or the left-hand side
176 -- of the enclosing assignment statement. The tag must be propagated
177 -- recursively to the tag-indeterminate actuals of the call.
178 -- Need clear description of the parameters Control and Actual, especially
179 -- since the comments above refer to actuals in the plural ???