Mercurial > hg > CbC > CbC_gcc
comparison gcc/ada/sem_disp.ads @ 111:04ced10e8804
gcc 7
author | kono |
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date | Fri, 27 Oct 2017 22:46:09 +0900 |
parents | |
children | 84e7813d76e9 |
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1 ------------------------------------------------------------------------------ | |
2 -- -- | |
3 -- GNAT COMPILER COMPONENTS -- | |
4 -- -- | |
5 -- S E M _ D I S P -- | |
6 -- -- | |
7 -- S p e c -- | |
8 -- -- | |
9 -- Copyright (C) 1992-2016, Free Software Foundation, Inc. -- | |
10 -- -- | |
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. -- | |
20 -- -- | |
21 -- GNAT was originally developed by the GNAT team at New York University. -- | |
22 -- Extensive contributions were provided by Ada Core Technologies Inc. -- | |
23 -- -- | |
24 ------------------------------------------------------------------------------ | |
25 | |
26 -- This package contains routines involved in tagged types and dynamic | |
27 -- dispatching. | |
28 | |
29 with Types; use Types; | |
30 package Sem_Disp is | |
31 | |
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. | |
38 | |
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. | |
44 | |
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. | |
56 | |
57 procedure Check_Operation_From_Incomplete_Type | |
58 (Subp : Entity_Id; | |
59 Typ : Entity_Id); | |
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??? | |
65 | |
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??? | |
72 | |
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. | |
76 | |
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. | |
80 | |
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. | |
85 | |
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. | |
99 | |
100 type Subprogram_List is array (Nat range <>) of Entity_Id; | |
101 -- Type returned by Inherited_Subprograms function | |
102 | |
103 function Inherited_Subprograms | |
104 (S : Entity_Id; | |
105 No_Interfaces : Boolean := False; | |
106 Interfaces_Only : Boolean := False; | |
107 One_Only : Boolean := False) return Subprogram_List; | |
108 -- Given the spec of a subprogram, this function gathers any inherited | |
109 -- subprograms from direct inheritance or via interfaces. The result is an | |
110 -- array of Entity_Ids of the specs of inherited subprograms. Returns a | |
111 -- null array if passed an Empty spec id. Note that the returned array | |
112 -- only includes subprograms and generic subprograms (and excludes any | |
113 -- other inherited entities, in particular enumeration literals). If | |
114 -- No_Interfaces is True, only return inherited subprograms not coming | |
115 -- from an interface. If Interfaces_Only is True, only return inherited | |
116 -- subprograms from interfaces. Otherwise, subprograms inherited directly | |
117 -- come first, starting with the closest ancestors, and are followed by | |
118 -- subprograms inherited from interfaces. At most one of No_Interfaces | |
119 -- and Interfaces_Only should be True. | |
120 -- | |
121 -- If One_Only is set, the search is discontinued as soon as one entry | |
122 -- is found. In this case the resulting array is either null or contains | |
123 -- exactly one element. | |
124 | |
125 function Is_Dynamically_Tagged (N : Node_Id) return Boolean; | |
126 -- Used to determine whether a call is dispatching, i.e. if it is | |
127 -- an expression of a class_Wide type, or a call to a function with | |
128 -- controlling result where at least one operand is dynamically tagged. | |
129 -- Also used to determine whether an entity has a class-wide type, or a | |
130 -- function call that dispatches on the result. Used to verify that all the | |
131 -- dependent expressions in a conditional expression are equally tagged. | |
132 | |
133 function Is_Null_Interface_Primitive (E : Entity_Id) return Boolean; | |
134 -- Returns True if E is a null procedure that is an interface primitive | |
135 | |
136 function Is_Overriding_Subprogram (E : Entity_Id) return Boolean; | |
137 -- Returns True if E is an overriding subprogram | |
138 | |
139 function Is_Tag_Indeterminate (N : Node_Id) return Boolean; | |
140 -- Returns true if the expression N is tag-indeterminate. An expression | |
141 -- is tag-indeterminate if it is a call that dispatches on result, and all | |
142 -- controlling operands are also indeterminate. Such a function call may | |
143 -- inherit a tag from an enclosing call. | |
144 | |
145 procedure Override_Dispatching_Operation | |
146 (Tagged_Type : Entity_Id; | |
147 Prev_Op : Entity_Id; | |
148 New_Op : Entity_Id; | |
149 Is_Wrapper : Boolean := False); | |
150 -- Replace an implicit dispatching operation of the type Tagged_Type | |
151 -- with an explicit one. Prev_Op is an inherited primitive operation which | |
152 -- is overridden by the explicit declaration of New_Op. Is_Wrapper is | |
153 -- True when New_Op is an internally generated wrapper of a controlling | |
154 -- function. The caller checks that Tagged_Type is indeed a tagged type. | |
155 | |
156 procedure Propagate_Tag (Control : Node_Id; Actual : Node_Id); | |
157 -- If a function call is tag-indeterminate, its controlling argument is | |
158 -- found in the context: either an enclosing call, or the left-hand side | |
159 -- of the enclosing assignment statement. The tag must be propagated | |
160 -- recursively to the tag-indeterminate actuals of the call. | |
161 -- Need clear description of the parameters Control and Actual, especially | |
162 -- since the comments above refer to actuals in the plural ??? | |
163 | |
164 end Sem_Disp; |