Implement -mmemcpy-strategy= and -mmemset-strategy= options
[official-gcc.git] / gcc / ada / exp_disp.ads
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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- E X P _ D I S P --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1992-2013, 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 ------------------------------------------------------------------------------
26 -- This package contains routines involved in tagged types and dynamic
27 -- dispatching expansion.
29 with Types; use Types;
31 package Exp_Disp is
33 -------------------------------------
34 -- Predefined primitive operations --
35 -------------------------------------
37 -- The predefined primitive operations (PPOs) are subprograms generated
38 -- by GNAT for a particular tagged type. Their role is to provide support
39 -- for different Ada language features such as the attribute 'Size or
40 -- handling of dispatching triggers in select statements. PPOs are created
41 -- when a tagged type is expanded or frozen. These subprograms are later
42 -- collected and inserted into the dispatch table of a tagged type at
43 -- fixed positions. Some of the PPOs that manipulate data in tagged objects
44 -- require the generation of thunks.
46 -- List of predefined primitive operations
48 -- Leading underscores designate reserved names. Bracketed numerical
49 -- values represent dispatch table slot numbers.
51 -- _Size (1) - implementation of the attribute 'Size for any tagged
52 -- type. Constructs of the form Prefix'Size are converted into
53 -- Prefix._Size.
55 -- TSS_Stream_Read (2) - implementation of the stream attribute Read
56 -- for any tagged type.
58 -- TSS_Stream_Write (3) - implementation of the stream attribute Write
59 -- for any tagged type.
61 -- TSS_Stream_Input (4) - implementation of the stream attribute Input
62 -- for any tagged type.
64 -- TSS_Stream_Output (5) - implementation of the stream attribute
65 -- Output for any tagged type.
67 -- Op_Eq (6) - implementation of the equality operator for any non-
68 -- limited tagged type.
70 -- _Assign (7) - implementation of the assignment operator for any
71 -- non-limited tagged type.
73 -- TSS_Deep_Adjust (8) - implementation of the finalization operation
74 -- Adjust for any non-limited tagged type.
76 -- TSS_Deep_Finalize (9) - implementation of the finalization
77 -- operation Finalize for any non-limited tagged type.
79 -- _Disp_Asynchronous_Select (10) - used in the expansion of ATC with
80 -- dispatching triggers. Null implementation for limited interfaces,
81 -- full body generation for types that implement limited interfaces,
82 -- not generated for the rest of the cases. See Expand_N_Asynchronous_
83 -- Select in Exp_Ch9 for more information.
85 -- _Disp_Conditional_Select (11) - used in the expansion of conditional
86 -- selects with dispatching triggers. Null implementation for limited
87 -- interfaces, full body generation for types that implement limited
88 -- interfaces, not generated for the rest of the cases. See Expand_N_
89 -- Conditional_Entry_Call in Exp_Ch9 for more information.
91 -- _Disp_Get_Prim_Op_Kind (12) - helper routine used in the expansion
92 -- of ATC with dispatching triggers. Null implementation for limited
93 -- interfaces, full body generation for types that implement limited
94 -- interfaces, not generated for the rest of the cases.
96 -- _Disp_Get_Task_Id (13) - helper routine used in the expansion of
97 -- Abort, attributes 'Callable and 'Terminated for task interface
98 -- class-wide types. Full body generation for task types, null
99 -- implementation for limited interfaces, not generated for the rest
100 -- of the cases. See Expand_N_Attribute_Reference in Exp_Attr and
101 -- Expand_N_Abort_Statement in Exp_Ch9 for more information.
103 -- _Disp_Requeue (14) - used in the expansion of dispatching requeue
104 -- statements. Null implementation is provided for protected, task
105 -- and synchronized interfaces. Protected and task types implementing
106 -- concurrent interfaces receive full bodies. See Expand_N_Requeue_
107 -- Statement in Exp_Ch9 for more information.
109 -- _Disp_Timed_Select (15) - used in the expansion of timed selects
110 -- with dispatching triggers. Null implementation for limited
111 -- interfaces, full body generation for types that implement limited
112 -- interfaces, not generated for the rest of the cases. See Expand_N_
113 -- Timed_Entry_Call for more information.
115 -- Life cycle of predefined primitive operations
117 -- The specifications and bodies of the PPOs are created by
118 -- Make_Predefined_Primitive_Specs and Predefined_Primitive_Bodies
119 -- in Exp_Ch3. The generated specifications are immediately analyzed,
120 -- while the bodies are left as freeze actions to the tagged type for
121 -- which they are created.
123 -- PPOs are collected and added to the Primitive_Operations list of
124 -- a type by the regular analysis mechanism.
126 -- PPOs are frozen by Exp_Ch3.Predefined_Primitive_Freeze
128 -- Thunks for PPOs are created by Make_DT
130 -- Dispatch table positions of PPOs are set by Set_All_DT_Position
132 -- Calls to PPOs proceed as regular dispatching calls. If the PPO
133 -- has a thunk, a call proceeds as a regular dispatching call with
134 -- a thunk.
136 -- Guidelines for addition of new predefined primitive operations
138 -- Update the value of constant Max_Predef_Prims in a-tags.ads to
139 -- indicate the new number of PPOs.
141 -- Introduce a new predefined name for the new PPO in Snames.ads and
142 -- Snames.adb.
144 -- Categorize the new PPO name as predefined by adding an entry in
145 -- Is_Predefined_Dispatching_Operation in Exp_Disp.
147 -- Generate the specification of the new PPO in Make_Predefined_
148 -- Primitive_Spec in Exp_Ch3.adb. The Is_Internal flag of the defining
149 -- identifier of the specification must be set to True.
151 -- Generate the body of the new PPO in Predefined_Primitive_Bodies in
152 -- Exp_Ch3.adb. The Is_Internal flag of the defining identifier of the
153 -- specification must be set to True.
155 -- If the new PPO requires a thunk, add an entry in Freeze_Subprogram
156 -- in Exp_Ch6.adb.
158 -- When generating calls to a PPO, use Find_Prim_Op from Exp_Util.ads
159 -- to retrieve the entity of the operation directly.
161 -- Number of predefined primitive operations added by the Expander
162 -- for a tagged type. If more predefined primitive operations are
163 -- added, the following items must be changed:
165 -- Ada.Tags.Max_Predef_Prims - indirect use
166 -- Exp_Disp.Default_Prim_Op_Position - indirect use
167 -- Exp_Disp.Set_All_DT_Position - direct use
169 procedure Apply_Tag_Checks (Call_Node : Node_Id);
170 -- Generate checks required on dispatching calls
172 function Building_Static_DT (Typ : Entity_Id) return Boolean;
173 pragma Inline (Building_Static_DT);
174 -- Returns true when building statically allocated dispatch tables
176 procedure Build_Static_Dispatch_Tables (N : Node_Id);
177 -- N is a library level package declaration or package body. Build the
178 -- static dispatch table of the tagged types defined at library level. In
179 -- case of package declarations with private part the generated nodes are
180 -- added at the end of the list of private declarations. Otherwise they are
181 -- added to the end of the list of public declarations. In case of package
182 -- bodies they are added to the end of the list of declarations of the
183 -- package body.
185 function Convert_Tag_To_Interface
186 (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
187 pragma Inline (Convert_Tag_To_Interface);
188 -- This function is used in class-wide interface conversions; the expanded
189 -- code generated to convert a tagged object to a class-wide interface type
190 -- involves referencing the tag component containing the secondary dispatch
191 -- table associated with the interface. Given the expression Expr that
192 -- references a tag component, we cannot generate an unchecked conversion
193 -- to leave the expression decorated with the class-wide interface type Typ
194 -- because an unchecked conversion cannot be seen as a no-op. An unchecked
195 -- conversion is conceptually a function call and therefore the RM allows
196 -- the backend to obtain a copy of the value of the actual object and store
197 -- it in some other place (like a register); in such case the interface
198 -- conversion is not equivalent to a displacement of the pointer to the
199 -- interface and any further displacement fails. Although the functionality
200 -- of this function is simple and could be done directly, the purpose of
201 -- this routine is to leave well documented in the sources these
202 -- occurrences.
204 -- If Expr is an N_Selected_Component that references a tag generate:
205 -- type ityp is non null access Typ;
206 -- ityp!(Expr'Address).all
208 -- if Expr is an N_Function_Call to Ada.Tags.Displace then generate:
209 -- type ityp is non null access Typ;
210 -- ityp!(Expr).all
212 function CPP_Num_Prims (Typ : Entity_Id) return Nat;
213 -- Return the number of primitives of the C++ part of the dispatch table.
214 -- For types that are not derivations of CPP types return 0.
216 procedure Expand_Dispatching_Call (Call_Node : Node_Id);
217 -- Expand the call to the operation through the dispatch table and perform
218 -- the required tag checks when appropriate. For CPP types tag checks are
219 -- not relevant.
221 procedure Expand_Interface_Actuals (Call_Node : Node_Id);
222 -- Ada 2005 (AI-251): Displace all the actuals corresponding to class-wide
223 -- interfaces to reference the interface tag of the actual object
225 procedure Expand_Interface_Conversion (N : Node_Id);
226 -- Ada 2005 (AI-251): N is a type-conversion node. Displace the pointer
227 -- to the object to give access to the interface tag associated with the
228 -- dispatch table of the target type.
230 procedure Expand_Interface_Thunk
231 (Prim : Node_Id;
232 Thunk_Id : out Entity_Id;
233 Thunk_Code : out Node_Id);
234 -- Ada 2005 (AI-251): When a tagged type implements abstract interfaces we
235 -- generate additional subprograms (thunks) associated with each primitive
236 -- Prim to have a layout compatible with the C++ ABI. The thunk displaces
237 -- the pointers to the actuals that depend on the controlling type before
238 -- transferring control to the target subprogram. If there is no need to
239 -- generate the thunk then Thunk_Id and Thunk_Code are set to Empty.
240 -- Otherwise they are set to the defining identifier and the subprogram
241 -- body of the generated thunk.
243 function Has_CPP_Constructors (Typ : Entity_Id) return Boolean;
244 -- Returns true if the type has CPP constructors
246 function Is_Expanded_Dispatching_Call (N : Node_Id) return Boolean;
247 -- Returns true if N is the expanded code of a dispatching call
249 function Is_Predefined_Dispatching_Operation (E : Entity_Id) return Boolean;
250 -- Ada 2005 (AI-251): Determines if E is a predefined primitive operation
252 function Is_Predefined_Internal_Operation (E : Entity_Id) return Boolean;
253 -- Similar to the previous one, but excludes stream operations, because
254 -- these may be overridden, and need extra formals, like user-defined
255 -- operations.
257 function Is_Predefined_Interface_Primitive (E : Entity_Id) return Boolean;
258 -- Ada 2005 (AI-345): Returns True if E is one of the predefined primitives
259 -- required to implement interfaces.
261 function Make_DT (Typ : Entity_Id; N : Node_Id := Empty) return List_Id;
262 -- Expand the declarations for the Dispatch Table. The node N is the
263 -- declaration that forces the generation of the table. It is used to place
264 -- error messages when the declaration leads to the freezing of a given
265 -- primitive operation that has an incomplete non- tagged formal.
267 function Make_Disp_Asynchronous_Select_Body
268 (Typ : Entity_Id) return Node_Id;
269 -- Ada 2005 (AI-345): Generate the body of the primitive operation of type
270 -- Typ used for dispatching in asynchronous selects. Generate a null body
271 -- if Typ is an interface type.
273 function Make_Disp_Asynchronous_Select_Spec
274 (Typ : Entity_Id) return Node_Id;
275 -- Ada 2005 (AI-345): Generate the specification of the primitive operation
276 -- of type Typ used for dispatching in asynchronous selects.
278 function Make_Disp_Conditional_Select_Body
279 (Typ : Entity_Id) return Node_Id;
280 -- Ada 2005 (AI-345): Generate the body of the primitive operation of type
281 -- Typ used for dispatching in conditional selects. Generate a null body
282 -- if Typ is an interface type.
284 function Make_Disp_Conditional_Select_Spec
285 (Typ : Entity_Id) return Node_Id;
286 -- Ada 2005 (AI-345): Generate the specification of the primitive operation
287 -- of type Typ used for dispatching in conditional selects.
289 function Make_Disp_Get_Prim_Op_Kind_Body
290 (Typ : Entity_Id) return Node_Id;
291 -- Ada 2005 (AI-345): Generate the body of the primitive operation of type
292 -- Typ used for retrieving the callable entity kind during dispatching in
293 -- asynchronous selects. Generate a null body if Typ is an interface type.
295 function Make_Disp_Get_Prim_Op_Kind_Spec
296 (Typ : Entity_Id) return Node_Id;
297 -- Ada 2005 (AI-345): Generate the specification of the primitive operation
298 -- of the type Typ use for retrieving the callable entity kind during
299 -- dispatching in asynchronous selects.
301 function Make_Disp_Get_Task_Id_Body
302 (Typ : Entity_Id) return Node_Id;
303 -- Ada 2005 (AI-345): Generate body of the primitive operation of type Typ
304 -- used for retrieving the _task_id field of a task interface class- wide
305 -- type. Generate a null body if Typ is an interface or a non-task type.
307 function Make_Disp_Get_Task_Id_Spec
308 (Typ : Entity_Id) return Node_Id;
309 -- Ada 2005 (AI-345): Generate the specification of the primitive operation
310 -- of type Typ used for retrieving the _task_id field of a task interface
311 -- class-wide type.
313 function Make_Disp_Requeue_Body
314 (Typ : Entity_Id) return Node_Id;
315 -- Ada 2005 (AI05-0030): Generate the body of the primitive operation of
316 -- type Typ used for dispatching on requeue statements. Generate a body
317 -- containing a single null-statement if Typ is an interface type.
319 function Make_Disp_Requeue_Spec
320 (Typ : Entity_Id) return Node_Id;
321 -- Ada 2005 (AI05-0030): Generate the specification of the primitive
322 -- operation of type Typ used for dispatching requeue statements.
324 function Make_Disp_Timed_Select_Body
325 (Typ : Entity_Id) return Node_Id;
326 -- Ada 2005 (AI-345): Generate the body of the primitive operation of type
327 -- Typ used for dispatching in timed selects. Generate a body containing
328 -- a single null-statement if Typ is an interface type.
330 function Make_Disp_Timed_Select_Spec
331 (Typ : Entity_Id) return Node_Id;
332 -- Ada 2005 (AI-345): Generate the specification of the primitive operation
333 -- of type Typ used for dispatching in timed selects.
335 function Make_Select_Specific_Data_Table
336 (Typ : Entity_Id) return List_Id;
337 -- Ada 2005 (AI-345): Create and populate the auxiliary table in the TSD
338 -- of Typ used for dispatching in asynchronous, conditional and timed
339 -- selects. Generate code to set the primitive operation kinds and entry
340 -- indexes of primitive operations and primitive wrappers.
342 function Make_Tags (Typ : Entity_Id) return List_Id;
343 -- Generate the entities associated with the primary and secondary tags of
344 -- Typ and fill the contents of Access_Disp_Table. In case of library level
345 -- tagged types this routine imports the forward declaration of the tag
346 -- entity, that will be declared and exported by Make_DT.
348 function Make_VM_TSD (Typ : Entity_Id) return List_Id;
349 -- Build the Type Specific Data record associated with tagged type Typ.
350 -- Invoked only when generating code for VM targets.
352 function Register_Primitive
353 (Loc : Source_Ptr;
354 Prim : Entity_Id) return List_Id;
355 -- Build code to register Prim in the primary or secondary dispatch table.
356 -- If Prim is associated with a secondary dispatch table then generate also
357 -- its thunk and register it in the associated secondary dispatch table.
358 -- In general the dispatch tables are always generated by Make_DT and
359 -- Make_Secondary_DT; this routine is only used in two corner cases:
361 -- 1) To construct the dispatch table of a tagged type whose parent
362 -- is a CPP_Class (see Build_Init_Procedure).
363 -- 2) To handle late overriding of dispatching operations (see
364 -- Check_Dispatching_Operation and Make_DT).
366 -- The caller is responsible for inserting the generated code in the
367 -- proper place.
369 procedure Set_All_DT_Position (Typ : Entity_Id);
370 -- Set the DT_Position field for each primitive operation. In the CPP
371 -- Class case check that no pragma CPP_Virtual is missing and that the
372 -- DT_Position are coherent
374 procedure Set_CPP_Constructors (Typ : Entity_Id);
375 -- Typ is a CPP_Class type. Create the Init procedures of that type
376 -- required to handle its default and non-default constructors. The
377 -- functions to which pragma CPP_Constructor is applied in the sources
378 -- are functions returning this type, and having an implicit access to the
379 -- target object in its first argument; such implicit argument is explicit
380 -- in the IP procedures built here.
382 procedure Set_DTC_Entity_Value
383 (Tagged_Type : Entity_Id;
384 Prim : Entity_Id);
385 -- Set the definite value of the DTC_Entity value associated with a given
386 -- primitive of a tagged type.
388 procedure Write_DT (Typ : Entity_Id);
389 pragma Export (Ada, Write_DT);
390 -- Debugging procedure (to be called within gdb)
392 end Exp_Disp;