1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2007, 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 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
25 ------------------------------------------------------------------------------
27 -- Type Support Subprogram (TSS) handling
29 with Namet; use Namet;
30 with Types; use Types;
34 -- A type support subprogram (TSS) is an internally generated function or
35 -- procedure that is associated with a particular type. Examples are the
36 -- implicit initialization procedure, and subprograms for the Input and
39 -- A given TSS is either generated once at the point of the declaration of
40 -- the type, or it is generated as needed in clients, but only one copy is
41 -- required in any one generated object file. The choice between these two
42 -- possibilities is made on a TSS-by-TSS basis depending on the estimation
43 -- of how likely the TSS is to be used. Initialization procedures fall in
44 -- the first category, for example, since it is likely that any declared
45 -- type will be used in a context requiring initialization, but the stream
46 -- attributes use the second approach, since it is more likely that they
47 -- will not be used at all, or will only be used in one client in any case.
49 -------------------------
50 -- Current Limitations --
51 -------------------------
53 -- In the current version of this package, only the case of generating a
54 -- TSS at the point of declaration of the type is accomodated. A clear
55 -- improvement would be to follow through with the full implementation
56 -- as described above, and also accomodate the requirement of generating
57 -- only one copy in a given object file.
59 -- For now, we deal with the local case by generating duplicate versions
60 -- of the TSS routine, which is clearly rather inefficient in space usage.
61 -- This is done by using Make_TSS_Name_Local to generate unique names
62 -- for the different instances of TSS routines in a given scope.
68 -- A TSS is identified by its Chars name. The name has the form typXY or
69 -- typ_<serial>XY, where typ is the type name, and XY are two characters
70 -- that identify the particular TSS routine. A unique serial number is
71 -- included for the case where several local instances of the same TSS
72 -- must be generated (see discussion under Make_TSS_Name_Local).
74 -- The following codes are used to denote TSSs:
76 -- Note: When making additions to this list, update the list in snames.adb
78 type TSS_Name_Type is new String (1 .. 2);
79 subtype TNT is TSS_Name_Type;
81 TSS_Deep_Adjust : constant TNT := "DA"; -- Deep Adjust
82 TSS_Deep_Finalize : constant TNT := "DF"; -- Deep Finalize
83 TSS_Deep_Initialize : constant TNT := "DI"; -- Deep Initialize
84 TSS_Composite_Equality : constant TNT := "EQ"; -- Composite Equality
85 TSS_From_Any : constant TNT := "FA"; -- PolyORB/DSA From_Any
86 TSS_Init_Proc : constant TNT := "IP"; -- Initialization Procedure
87 TSS_RAS_Access : constant TNT := "RA"; -- RAS type access
88 TSS_RAS_Dereference : constant TNT := "RD"; -- RAS type deference
89 TSS_Rep_To_Pos : constant TNT := "RP"; -- Rep to Pos conversion
90 TSS_Slice_Assign : constant TNT := "SA"; -- Slice assignment
91 TSS_Stream_Input : constant TNT := "SI"; -- Stream Input attribute
92 TSS_Stream_Output : constant TNT := "SO"; -- Stream Output attribute
93 TSS_Stream_Read : constant TNT := "SR"; -- Stream Read attribute
94 TSS_Stream_Write : constant TNT := "SW"; -- Stream Write attribute
95 TSS_To_Any : constant TNT := "TA"; -- PolyORB/DSA To_Any
96 TSS_TypeCode : constant TNT := "TC"; -- PolyORB/DSA TypeCode
98 -- The array below contains all valid TSS names
100 TSS_Names : constant array (Natural range <>) of TSS_Name_Type :=
104 TSS_Composite_Equality,
118 TSS_Null : constant TNT := " ";
119 -- Dummy entry used to indicated that this is not really a TSS
121 function Get_TSS_Name (E : Entity_Id) return TSS_Name_Type;
122 -- Given an entity, if it is a TSS, then return the corresponding TSS
123 -- name type, otherwise return TSS_Null.
125 function Make_TSS_Name
127 Nam : TSS_Name_Type) return Name_Id;
128 -- Construct the name as described above for the given TSS routine
129 -- identified by Nam for the type identified by Typ.
131 function Make_TSS_Name_Local
133 Nam : TSS_Name_Type) return Name_Id;
134 -- Similar to the above call, but a string of the form _nnn is inserted
135 -- before the TSS code suffix, where nnn is a unique serial number. This
136 -- is used when multiple instances of the same TSS routine may be
137 -- generated in the same scope (see also discussion above of current
140 function Make_Init_Proc_Name (Typ : Entity_Id) return Name_Id;
141 -- Version for init procs, same as Make_TSS_Name (Typ, TSS_Init_Proc)
143 function Is_TSS (E : Entity_Id; Nam : TSS_Name_Type) return Boolean;
144 -- Determines if given entity (E) is the name of a TSS identified by Nam
146 function Is_TSS (N : Name_Id; Nam : TSS_Name_Type) return Boolean;
147 -- Same test applied directly to a Name_Id value
149 function Is_Init_Proc (E : Entity_Id) return Boolean;
150 -- Version for init procs, same as Is_TSS (E, TSS_Init_Proc);
152 -----------------------------------------
153 -- TSS Data structures and Subprograms --
154 -----------------------------------------
156 -- The TSS's for a given type are stored in an element list associated with
157 -- the type, and referenced from the TSS_Elist field of the N_Freeze_Entity
158 -- node associated with the type (all types that need TSS's always need to
159 -- be explicitly frozen, so the N_Freeze_Entity node always exists).
161 function TSS (Typ : Entity_Id; Nam : TSS_Name_Type) return Entity_Id;
162 -- Finds the TSS with the given name associated with the given type
163 -- If no such TSS exists, then Empty is returned;
165 function TSS (Typ : Entity_Id; Nam : Name_Id) return Entity_Id;
166 -- Finds the TSS with the given name associated with the given type. If
167 -- no such TSS exists, then Empty is returned.
169 function Same_TSS (E1, E2 : Entity_Id) return Boolean;
170 -- Returns True if E1 and E2 are the same kind of TSS, even if the names
171 -- are different (i.e. if the names of E1 and E2 end with two upper case
172 -- letters that are the same).
174 procedure Set_TSS (Typ : Entity_Id; TSS : Entity_Id);
175 -- This procedure is used to install a newly created TSS. The second
176 -- argument is the entity for such a new TSS. This entity is placed in the
177 -- TSS list for the type given as the first argument, replacing an old
178 -- entry of the same name if one was present. The tree for the body of this
179 -- TSS, which is not analyzed yet, is placed in the actions field of the
180 -- freeze node for the type. All such bodies are inserted into the main
181 -- tree and analyzed at the point at which the freeze node itself is
184 procedure Copy_TSS (TSS : Entity_Id; Typ : Entity_Id);
185 -- Given an existing TSS for another type (which is already installed,
186 -- analyzed and expanded), install it as the corresponding TSS for Typ.
187 -- Note that this just copies a reference, not the tree. This can also be
188 -- used to initially install a TSS in the case where the subprogram for the
189 -- TSS has already been created and its declaration processed.
191 function Init_Proc (Typ : Entity_Id) return Entity_Id;
192 pragma Inline (Init_Proc);
193 -- Obtains the _init TSS entry for the given type. This function call is
194 -- equivalent to TSS (Typ, Name_uInit). The _init TSS is the procedure
195 -- used to initialize otherwise uninitialized instances of a type. If
196 -- there is no _init TSS, then the type requires no initialization. Note
197 -- that subtypes and implicit types never have an _init TSS since subtype
198 -- objects are always initialized using the initialization procedure for
199 -- the corresponding base type (see Base_Init_Proc function). A special
200 -- case arises for concurrent types. Such types do not themselves have an
201 -- init proc TSS, but initialization is required. The init proc used is
202 -- the one for the corresponding record type (see Base_Init_Proc).
204 function Base_Init_Proc (Typ : Entity_Id) return Entity_Id;
205 -- Obtains the _Init TSS entry from the base type of the entity, and also
206 -- deals with going indirect through the Corresponding_Record_Type field
207 -- for concurrent objects (which are initialized with the initialization
208 -- routine for the corresponding record type). Returns Empty if there is
209 -- no _Init TSS entry for the base type.
211 procedure Set_Init_Proc (Typ : Entity_Id; Init : Entity_Id);
212 pragma Inline (Set_Init_Proc);
213 -- The second argument is the _init TSS to be established for the type
214 -- given as the first argument. Equivalent to Set_TSS (Typ, Init).
216 function Has_Non_Null_Base_Init_Proc (Typ : Entity_Id) return Boolean;
217 -- Returns true if the given type has a defined Base_Init_Proc and
218 -- this init proc is not a null init proc (null init procs occur as
219 -- a result of the processing for Initialize_Scalars. This function
220 -- is used to test for the presence of an init proc in cases where
221 -- a null init proc is considered equivalent to no init proc.
223 function Find_Inherited_TSS
225 Nam : TSS_Name_Type) return Entity_Id;
226 -- Returns the TSS of name Nam of Typ, or of its closest ancestor defining
227 -- such a TSS. Empty is returned is neither Typ nor any of its ancestors