1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 2010-2015, 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. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 -- This package defines the aspects that are recognized by GNAT in aspect
33 -- specifications. It also contains the subprograms for storing/retrieving
34 -- aspect specifications from the tree. The semantic processing for aspect
35 -- specifications is found in Sem_Ch13.Analyze_Aspect_Specifications.
37 ------------------------
38 -- Adding New Aspects --
39 ------------------------
41 -- In general, each aspect should have a corresponding pragma, so that the
42 -- newly developed functionality is available for Ada versions < Ada 2012.
43 -- When both are defined, it is convenient to first transform the aspect into
44 -- an equivalent pragma in Sem_Ch13.Analyze_Aspect_Specifications, and then
45 -- analyze the pragma in Sem_Prag.Analyze_Pragma.
47 -- To add a new aspect, you need to do the following
49 -- 1. Create a name in snames.ads-tmpl
51 -- 2. Create a value in type Aspect_Id in this unit
53 -- 3. Add a value for the aspect in the global arrays defined in this unit
55 -- 4. Add code for the aspect in Sem_Ch13.Analyze_Aspect_Specifications.
56 -- This may involve adding some nodes to the tree to perform additional
59 -- 5. If the semantic analysis of expressions/names in the aspect should not
60 -- occur at the point the aspect is defined, add code in the adequate
61 -- semantic analysis procedure for the aspect. For example, this is the
62 -- case for aspects Pre and Post on subprograms, which are pre-analyzed
63 -- at the end of the declaration list to which the subprogram belongs,
64 -- and fully analyzed (possibly with expansion) during the semantic
65 -- analysis of subprogram bodies.
67 with Namet; use Namet;
68 with Snames; use Snames;
69 with Types; use Types;
73 -- Type defining recognized aspects
76 (No_Aspect, -- Dummy entry for no aspect
77 Aspect_Abstract_State, -- GNAT
80 Aspect_Annotate, -- GNAT
81 Aspect_Async_Readers, -- GNAT
82 Aspect_Async_Writers, -- GNAT
83 Aspect_Attach_Handler,
85 Aspect_Component_Size,
86 Aspect_Constant_After_Elaboration, -- GNAT
87 Aspect_Constant_Indexing,
88 Aspect_Contract_Cases, -- GNAT
91 Aspect_Default_Component_Value,
92 Aspect_Default_Initial_Condition, -- GNAT
93 Aspect_Default_Iterator,
94 Aspect_Default_Storage_Pool,
96 Aspect_Depends, -- GNAT
97 Aspect_Dimension, -- GNAT
98 Aspect_Dimension_System, -- GNAT
99 Aspect_Dispatching_Domain,
100 Aspect_Dynamic_Predicate,
101 Aspect_Effective_Reads, -- GNAT
102 Aspect_Effective_Writes, -- GNAT
103 Aspect_Extensions_Visible, -- GNAT
104 Aspect_External_Name,
106 Aspect_Ghost, -- GNAT
107 Aspect_Global, -- GNAT
108 Aspect_Implicit_Dereference,
109 Aspect_Initial_Condition, -- GNAT
110 Aspect_Initializes, -- GNAT
112 Aspect_Interrupt_Priority,
113 Aspect_Invariant, -- GNAT
114 Aspect_Iterator_Element,
115 Aspect_Iterable, -- GNAT
117 Aspect_Linker_Section, -- GNAT
118 Aspect_Machine_Radix,
119 Aspect_Object_Size, -- GNAT
120 Aspect_Obsolescent, -- GNAT
122 Aspect_Part_Of, -- GNAT
124 Aspect_Postcondition,
127 Aspect_Predicate, -- GNAT
130 Aspect_Refined_Depends, -- GNAT
131 Aspect_Refined_Global, -- GNAT
132 Aspect_Refined_Post, -- GNAT
133 Aspect_Refined_State, -- GNAT
134 Aspect_Relative_Deadline,
135 Aspect_Scalar_Storage_Order, -- GNAT
136 Aspect_Simple_Storage_Pool, -- GNAT
139 Aspect_SPARK_Mode, -- GNAT
140 Aspect_Static_Predicate,
145 Aspect_Synchronization,
146 Aspect_Test_Case, -- GNAT
147 Aspect_Type_Invariant,
148 Aspect_Unimplemented, -- GNAT
150 Aspect_Value_Size, -- GNAT
151 Aspect_Variable_Indexing,
152 Aspect_Volatile_Function, -- GNAT
153 Aspect_Warnings, -- GNAT
156 -- The following aspects correspond to library unit pragmas
158 Aspect_All_Calls_Remote,
159 Aspect_Elaborate_Body,
160 Aspect_No_Elaboration_Code_All, -- GNAT
163 Aspect_Remote_Call_Interface,
165 Aspect_Shared_Passive,
166 Aspect_Universal_Data, -- GNAT
168 -- Remaining aspects have a static boolean value that turns the aspect
169 -- on or off. They all correspond to pragmas, but are only converted to
170 -- the pragmas where the value is True. A value of False normally means
171 -- that the aspect is ignored, except in the case of derived types where
172 -- the aspect value is inherited from the parent, in which case, we do
173 -- not allow False if we inherit a True value from the parent.
177 Aspect_Atomic_Components,
178 Aspect_Disable_Controlled, -- GNAT
179 Aspect_Discard_Names,
181 Aspect_Favor_Top_Level, -- GNAT
183 Aspect_Independent_Components,
186 Aspect_Inline_Always, -- GNAT
187 Aspect_Interrupt_Handler,
188 Aspect_Lock_Free, -- GNAT
190 Aspect_No_Tagged_Streams, -- GNAT
192 Aspect_Persistent_BSS, -- GNAT
193 Aspect_Preelaborable_Initialization,
194 Aspect_Pure_Function, -- GNAT
195 Aspect_Remote_Access_Type, -- GNAT
196 Aspect_Shared, -- GNAT (equivalent to Atomic)
197 Aspect_Simple_Storage_Pool_Type, -- GNAT
198 Aspect_Suppress_Debug_Info, -- GNAT
199 Aspect_Suppress_Initialization, -- GNAT
200 Aspect_Thread_Local_Storage, -- GNAT
201 Aspect_Unchecked_Union,
202 Aspect_Universal_Aliasing, -- GNAT
203 Aspect_Unmodified, -- GNAT
204 Aspect_Unreferenced, -- GNAT
205 Aspect_Unreferenced_Objects, -- GNAT
207 Aspect_Volatile_Components,
208 Aspect_Volatile_Full_Access); -- GNAT
210 subtype Aspect_Id_Exclude_No_Aspect is
211 Aspect_Id range Aspect_Id'Succ (No_Aspect) .. Aspect_Id'Last;
212 -- Aspect_Id's excluding No_Aspect
214 -- The following array indicates aspects that accept 'Class
216 Class_Aspect_OK : constant array (Aspect_Id) of Boolean :=
217 (Aspect_Input => True,
218 Aspect_Invariant => True,
219 Aspect_Output => True,
221 Aspect_Predicate => True,
224 Aspect_Write => True,
225 Aspect_Type_Invariant => True,
228 -- The following array identifies all implementation defined aspects
230 Implementation_Defined_Aspect : constant array (Aspect_Id) of Boolean :=
231 (Aspect_Abstract_State => True,
232 Aspect_Annotate => True,
233 Aspect_Async_Readers => True,
234 Aspect_Async_Writers => True,
235 Aspect_Constant_After_Elaboration => True,
236 Aspect_Contract_Cases => True,
237 Aspect_Depends => True,
238 Aspect_Dimension => True,
239 Aspect_Dimension_System => True,
240 Aspect_Effective_Reads => True,
241 Aspect_Effective_Writes => True,
242 Aspect_Extensions_Visible => True,
243 Aspect_Favor_Top_Level => True,
244 Aspect_Ghost => True,
245 Aspect_Global => True,
246 Aspect_Inline_Always => True,
247 Aspect_Invariant => True,
248 Aspect_Lock_Free => True,
249 Aspect_Object_Size => True,
250 Aspect_Persistent_BSS => True,
251 Aspect_Predicate => True,
252 Aspect_Pure_Function => True,
253 Aspect_Remote_Access_Type => True,
254 Aspect_Scalar_Storage_Order => True,
255 Aspect_Shared => True,
256 Aspect_Simple_Storage_Pool => True,
257 Aspect_Simple_Storage_Pool_Type => True,
258 Aspect_Suppress_Debug_Info => True,
259 Aspect_Suppress_Initialization => True,
260 Aspect_Thread_Local_Storage => True,
261 Aspect_Test_Case => True,
262 Aspect_Universal_Aliasing => True,
263 Aspect_Universal_Data => True,
264 Aspect_Unmodified => True,
265 Aspect_Unreferenced => True,
266 Aspect_Unreferenced_Objects => True,
267 Aspect_Value_Size => True,
268 Aspect_Volatile_Function => True,
269 Aspect_Warnings => True,
272 -- The following array indicates aspects for which multiple occurrences of
273 -- the same aspect attached to the same declaration are allowed.
275 No_Duplicates_Allowed : constant array (Aspect_Id) of Boolean :=
276 (Aspect_Annotate => False,
277 Aspect_Test_Case => False,
280 -- The following subtype defines aspects corresponding to library unit
281 -- pragmas, these can only validly appear as aspects for library units,
282 -- and result in a corresponding pragma being inserted immediately after
283 -- the occurrence of the aspect.
285 subtype Library_Unit_Aspects is
286 Aspect_Id range Aspect_All_Calls_Remote .. Aspect_Universal_Data;
288 -- The following subtype defines aspects accepting an optional static
289 -- boolean parameter indicating if the aspect should be active or
290 -- cancelling. If the parameter is missing the effective value is True,
291 -- enabling the aspect. If the parameter is present it must be a static
292 -- expression of type Standard.Boolean. If the value is True, then the
293 -- aspect is enabled. If it is False, the aspect is disabled.
295 subtype Boolean_Aspects is
296 Aspect_Id range Aspect_Asynchronous .. Aspect_Id'Last;
298 subtype Pre_Post_Aspects is
299 Aspect_Id range Aspect_Post .. Aspect_Precondition;
301 -- The following type is used for indicating allowed expression forms
303 type Aspect_Expression is
304 (Expression, -- Required expression
305 Name, -- Required name
306 Optional_Expression, -- Optional boolean expression
307 Optional_Name); -- Optional name
309 -- The following array indicates what argument type is required
311 Aspect_Argument : constant array (Aspect_Id) of Aspect_Expression :=
312 (No_Aspect => Optional_Expression,
313 Aspect_Abstract_State => Expression,
314 Aspect_Address => Expression,
315 Aspect_Alignment => Expression,
316 Aspect_Annotate => Expression,
317 Aspect_Async_Readers => Optional_Expression,
318 Aspect_Async_Writers => Optional_Expression,
319 Aspect_Attach_Handler => Expression,
320 Aspect_Bit_Order => Expression,
321 Aspect_Component_Size => Expression,
322 Aspect_Constant_After_Elaboration => Optional_Expression,
323 Aspect_Constant_Indexing => Name,
324 Aspect_Contract_Cases => Expression,
325 Aspect_Convention => Name,
326 Aspect_CPU => Expression,
327 Aspect_Default_Component_Value => Expression,
328 Aspect_Default_Initial_Condition => Optional_Expression,
329 Aspect_Default_Iterator => Name,
330 Aspect_Default_Storage_Pool => Expression,
331 Aspect_Default_Value => Expression,
332 Aspect_Depends => Expression,
333 Aspect_Dimension => Expression,
334 Aspect_Dimension_System => Expression,
335 Aspect_Dispatching_Domain => Expression,
336 Aspect_Dynamic_Predicate => Expression,
337 Aspect_Effective_Reads => Optional_Expression,
338 Aspect_Effective_Writes => Optional_Expression,
339 Aspect_Extensions_Visible => Optional_Expression,
340 Aspect_External_Name => Expression,
341 Aspect_External_Tag => Expression,
342 Aspect_Ghost => Optional_Expression,
343 Aspect_Global => Expression,
344 Aspect_Implicit_Dereference => Name,
345 Aspect_Initial_Condition => Expression,
346 Aspect_Initializes => Expression,
347 Aspect_Input => Name,
348 Aspect_Interrupt_Priority => Expression,
349 Aspect_Invariant => Expression,
350 Aspect_Iterable => Expression,
351 Aspect_Iterator_Element => Name,
352 Aspect_Link_Name => Expression,
353 Aspect_Linker_Section => Expression,
354 Aspect_Machine_Radix => Expression,
355 Aspect_Object_Size => Expression,
356 Aspect_Obsolescent => Optional_Expression,
357 Aspect_Output => Name,
358 Aspect_Part_Of => Expression,
359 Aspect_Post => Expression,
360 Aspect_Postcondition => Expression,
361 Aspect_Pre => Expression,
362 Aspect_Precondition => Expression,
363 Aspect_Predicate => Expression,
364 Aspect_Priority => Expression,
366 Aspect_Refined_Depends => Expression,
367 Aspect_Refined_Global => Expression,
368 Aspect_Refined_Post => Expression,
369 Aspect_Refined_State => Expression,
370 Aspect_Relative_Deadline => Expression,
371 Aspect_Scalar_Storage_Order => Expression,
372 Aspect_Simple_Storage_Pool => Name,
373 Aspect_Size => Expression,
374 Aspect_Small => Expression,
375 Aspect_SPARK_Mode => Optional_Name,
376 Aspect_Static_Predicate => Expression,
377 Aspect_Storage_Pool => Name,
378 Aspect_Storage_Size => Expression,
379 Aspect_Stream_Size => Expression,
380 Aspect_Suppress => Name,
381 Aspect_Synchronization => Name,
382 Aspect_Test_Case => Expression,
383 Aspect_Type_Invariant => Expression,
384 Aspect_Unimplemented => Optional_Expression,
385 Aspect_Unsuppress => Name,
386 Aspect_Value_Size => Expression,
387 Aspect_Variable_Indexing => Name,
388 Aspect_Volatile_Function => Optional_Expression,
389 Aspect_Warnings => Name,
390 Aspect_Write => Name,
392 Boolean_Aspects => Optional_Expression,
393 Library_Unit_Aspects => Optional_Expression);
395 -----------------------------------------
396 -- Table Linking Names and Aspect_Id's --
397 -----------------------------------------
399 -- Table linking aspect names and id's
401 Aspect_Names : constant array (Aspect_Id) of Name_Id :=
402 (No_Aspect => No_Name,
403 Aspect_Abstract_State => Name_Abstract_State,
404 Aspect_Address => Name_Address,
405 Aspect_Alignment => Name_Alignment,
406 Aspect_All_Calls_Remote => Name_All_Calls_Remote,
407 Aspect_Annotate => Name_Annotate,
408 Aspect_Async_Readers => Name_Async_Readers,
409 Aspect_Async_Writers => Name_Async_Writers,
410 Aspect_Asynchronous => Name_Asynchronous,
411 Aspect_Atomic => Name_Atomic,
412 Aspect_Atomic_Components => Name_Atomic_Components,
413 Aspect_Attach_Handler => Name_Attach_Handler,
414 Aspect_Bit_Order => Name_Bit_Order,
415 Aspect_Component_Size => Name_Component_Size,
416 Aspect_Constant_After_Elaboration => Name_Constant_After_Elaboration,
417 Aspect_Constant_Indexing => Name_Constant_Indexing,
418 Aspect_Contract_Cases => Name_Contract_Cases,
419 Aspect_Convention => Name_Convention,
420 Aspect_CPU => Name_CPU,
421 Aspect_Default_Component_Value => Name_Default_Component_Value,
422 Aspect_Default_Initial_Condition => Name_Default_Initial_Condition,
423 Aspect_Default_Iterator => Name_Default_Iterator,
424 Aspect_Default_Storage_Pool => Name_Default_Storage_Pool,
425 Aspect_Default_Value => Name_Default_Value,
426 Aspect_Depends => Name_Depends,
427 Aspect_Dimension => Name_Dimension,
428 Aspect_Dimension_System => Name_Dimension_System,
429 Aspect_Disable_Controlled => Name_Disable_Controlled,
430 Aspect_Discard_Names => Name_Discard_Names,
431 Aspect_Dispatching_Domain => Name_Dispatching_Domain,
432 Aspect_Dynamic_Predicate => Name_Dynamic_Predicate,
433 Aspect_Effective_Reads => Name_Effective_Reads,
434 Aspect_Effective_Writes => Name_Effective_Writes,
435 Aspect_Elaborate_Body => Name_Elaborate_Body,
436 Aspect_Export => Name_Export,
437 Aspect_Extensions_Visible => Name_Extensions_Visible,
438 Aspect_External_Name => Name_External_Name,
439 Aspect_External_Tag => Name_External_Tag,
440 Aspect_Favor_Top_Level => Name_Favor_Top_Level,
441 Aspect_Ghost => Name_Ghost,
442 Aspect_Global => Name_Global,
443 Aspect_Implicit_Dereference => Name_Implicit_Dereference,
444 Aspect_Import => Name_Import,
445 Aspect_Independent => Name_Independent,
446 Aspect_Independent_Components => Name_Independent_Components,
447 Aspect_Inline => Name_Inline,
448 Aspect_Inline_Always => Name_Inline_Always,
449 Aspect_Initial_Condition => Name_Initial_Condition,
450 Aspect_Initializes => Name_Initializes,
451 Aspect_Input => Name_Input,
452 Aspect_Interrupt_Handler => Name_Interrupt_Handler,
453 Aspect_Interrupt_Priority => Name_Interrupt_Priority,
454 Aspect_Invariant => Name_Invariant,
455 Aspect_Iterator_Element => Name_Iterator_Element,
456 Aspect_Iterable => Name_Iterable,
457 Aspect_Link_Name => Name_Link_Name,
458 Aspect_Linker_Section => Name_Linker_Section,
459 Aspect_Lock_Free => Name_Lock_Free,
460 Aspect_Machine_Radix => Name_Machine_Radix,
461 Aspect_No_Elaboration_Code_All => Name_No_Elaboration_Code_All,
462 Aspect_No_Return => Name_No_Return,
463 Aspect_No_Tagged_Streams => Name_No_Tagged_Streams,
464 Aspect_Object_Size => Name_Object_Size,
465 Aspect_Obsolescent => Name_Obsolescent,
466 Aspect_Output => Name_Output,
467 Aspect_Pack => Name_Pack,
468 Aspect_Part_Of => Name_Part_Of,
469 Aspect_Persistent_BSS => Name_Persistent_BSS,
470 Aspect_Post => Name_Post,
471 Aspect_Postcondition => Name_Postcondition,
472 Aspect_Pre => Name_Pre,
473 Aspect_Precondition => Name_Precondition,
474 Aspect_Predicate => Name_Predicate,
475 Aspect_Preelaborable_Initialization => Name_Preelaborable_Initialization,
476 Aspect_Preelaborate => Name_Preelaborate,
477 Aspect_Priority => Name_Priority,
478 Aspect_Pure => Name_Pure,
479 Aspect_Pure_Function => Name_Pure_Function,
480 Aspect_Read => Name_Read,
481 Aspect_Refined_Depends => Name_Refined_Depends,
482 Aspect_Refined_Global => Name_Refined_Global,
483 Aspect_Refined_Post => Name_Refined_Post,
484 Aspect_Refined_State => Name_Refined_State,
485 Aspect_Relative_Deadline => Name_Relative_Deadline,
486 Aspect_Remote_Access_Type => Name_Remote_Access_Type,
487 Aspect_Remote_Call_Interface => Name_Remote_Call_Interface,
488 Aspect_Remote_Types => Name_Remote_Types,
489 Aspect_Scalar_Storage_Order => Name_Scalar_Storage_Order,
490 Aspect_Shared => Name_Shared,
491 Aspect_Shared_Passive => Name_Shared_Passive,
492 Aspect_Simple_Storage_Pool => Name_Simple_Storage_Pool,
493 Aspect_Simple_Storage_Pool_Type => Name_Simple_Storage_Pool_Type,
494 Aspect_Size => Name_Size,
495 Aspect_Small => Name_Small,
496 Aspect_SPARK_Mode => Name_SPARK_Mode,
497 Aspect_Static_Predicate => Name_Static_Predicate,
498 Aspect_Storage_Pool => Name_Storage_Pool,
499 Aspect_Storage_Size => Name_Storage_Size,
500 Aspect_Stream_Size => Name_Stream_Size,
501 Aspect_Suppress => Name_Suppress,
502 Aspect_Suppress_Debug_Info => Name_Suppress_Debug_Info,
503 Aspect_Suppress_Initialization => Name_Suppress_Initialization,
504 Aspect_Thread_Local_Storage => Name_Thread_Local_Storage,
505 Aspect_Synchronization => Name_Synchronization,
506 Aspect_Test_Case => Name_Test_Case,
507 Aspect_Type_Invariant => Name_Type_Invariant,
508 Aspect_Unchecked_Union => Name_Unchecked_Union,
509 Aspect_Unimplemented => Name_Unimplemented,
510 Aspect_Universal_Aliasing => Name_Universal_Aliasing,
511 Aspect_Universal_Data => Name_Universal_Data,
512 Aspect_Unmodified => Name_Unmodified,
513 Aspect_Unreferenced => Name_Unreferenced,
514 Aspect_Unreferenced_Objects => Name_Unreferenced_Objects,
515 Aspect_Unsuppress => Name_Unsuppress,
516 Aspect_Value_Size => Name_Value_Size,
517 Aspect_Variable_Indexing => Name_Variable_Indexing,
518 Aspect_Volatile => Name_Volatile,
519 Aspect_Volatile_Components => Name_Volatile_Components,
520 Aspect_Volatile_Full_Access => Name_Volatile_Full_Access,
521 Aspect_Volatile_Function => Name_Volatile_Function,
522 Aspect_Warnings => Name_Warnings,
523 Aspect_Write => Name_Write);
525 function Get_Aspect_Id (Name : Name_Id) return Aspect_Id;
526 pragma Inline (Get_Aspect_Id);
527 -- Given a name Nam, returns the corresponding aspect id value. If the name
528 -- does not match any aspect, then No_Aspect is returned as the result.
530 function Get_Aspect_Id (Aspect : Node_Id) return Aspect_Id;
531 pragma Inline (Get_Aspect_Id);
532 -- Given an aspect specification, return the corresponding aspect_id value.
533 -- If the name does not match any aspect, return No_Aspect.
535 ------------------------------------
536 -- Delaying Evaluation of Aspects --
537 ------------------------------------
539 -- The RM requires that all language defined aspects taking an expression
540 -- delay evaluation of the expression till the freeze point of the entity
541 -- to which the aspect applies. This allows forward references, and is of
542 -- use for example in connection with preconditions and postconditions
543 -- where the requirement of making all references in contracts to local
544 -- functions be backwards references would be onerous.
546 -- For consistency, even attributes like Size are delayed, so we can do:
548 -- type A is range 1 .. 10
549 -- with Size => Not_Defined_Yet;
551 -- Not_Defined_Yet : constant := 64;
553 -- Resulting in A having a size of 64, which gets set when A is frozen.
554 -- Furthermore, we can have a situation like
556 -- type A is range 1 .. 10
557 -- with Size => Not_Defined_Yet;
561 -- Not_Defined_Yet : constant := 64;
563 -- where the Size of A is considered to have been previously specified at
564 -- the point of derivation, even though the actual value of the size is
565 -- not known yet, and in this example B inherits the size value of 64.
567 -- Our normal implementation model (prior to Ada 2012) was simply to copy
568 -- inheritable attributes at the point of derivation. Then any subsequent
569 -- representation items apply either to the parent type, not affecting the
570 -- derived type, or to the derived type, not affecting the parent type.
572 -- To deal with the delayed aspect case, we use two flags. The first is
573 -- set on the parent type if it has delayed representation aspects. This
574 -- flag Has_Delayed_Rep_Aspects indicates that if we derive from this type
575 -- we have to worry about making sure we inherit any delayed aspects. The
576 -- second flag is set on a derived type: May_Have_Inherited_Rep_Aspects
577 -- is set if the parent type has Has_Delayed_Rep_Aspects set.
579 -- When we freeze a derived type, if the May_Have_Inherited_Rep_Aspects
580 -- flag is set, then we call Freeze.Inherit_Delayed_Rep_Aspects when
581 -- the derived type is frozen, which deals with the necessary copying of
582 -- information from the parent type, which must be frozen at that point
583 -- (since freezing the derived type first freezes the parent type).
585 -- SPARK 2014 aspects do not follow the general delay mechanism as they
586 -- act as annotations and cannot modify the attributes of their related
587 -- constructs. To handle forward references in such aspects, the compiler
588 -- delays the analysis of their respective pragmas by collecting them in
589 -- N_Contract nodes. The pragmas are then analyzed at the end of the
590 -- declarative region which contains the related construct. For details,
591 -- see routines Analyze_xxx_In_Decl_Part.
593 -- The following shows which aspects are delayed. There are three cases:
597 -- This aspect is not a representation aspect that can be inherited and
598 -- is always delayed, as required by the language definition.
601 -- There are two cases. There are language defined aspects like
602 -- Convention where the "expression" is simply an uninterpreted
603 -- identifier, and there is no issue of evaluating it and thus no
604 -- issue of delaying the evaluation. The second case is implementation
605 -- defined aspects where we have decided that we don't want to allow
606 -- delays (and for our own aspects we can do what we like).
609 -- These are the cases of representation aspects that are in general
610 -- delayed, and where there is a potential issue of derived types that
611 -- inherit delayed representation values.
613 -- Note: even if this table indicates that an aspect is delayed, we never
614 -- delay Boolean aspects that have a missing expression (taken as True),
615 -- or expressions for delayed rep items that consist of an integer literal
616 -- (most cases of Size etc. in practice), since in these cases we know we
617 -- can get the value of the expression without delay. Note that we still
618 -- need to delay Boolean aspects that are specifically set to True:
620 -- type R is array (0 .. 31) of Boolean
621 -- with Pack => True;
622 -- True : constant Boolean := False;
624 -- This is nonsense, but we need to make it work and result in R not
625 -- being packed, and if we have something like:
627 -- type R is array (0 .. 31) of Boolean
628 -- with Pack => True;
630 -- True : constant Boolean := False;
632 -- This is illegal because the visibility of True changes after the freeze
633 -- point, which is not allowed, and we need the delay mechanism to properly
634 -- diagnose this error.
636 Aspect_Delay : constant array (Aspect_Id) of Delay_Type :=
637 (No_Aspect => Always_Delay,
638 Aspect_Address => Always_Delay,
639 Aspect_All_Calls_Remote => Always_Delay,
640 Aspect_Asynchronous => Always_Delay,
641 Aspect_Attach_Handler => Always_Delay,
642 Aspect_Constant_Indexing => Always_Delay,
643 Aspect_CPU => Always_Delay,
644 Aspect_Default_Iterator => Always_Delay,
645 Aspect_Default_Storage_Pool => Always_Delay,
646 Aspect_Default_Value => Always_Delay,
647 Aspect_Default_Component_Value => Always_Delay,
648 Aspect_Discard_Names => Always_Delay,
649 Aspect_Dispatching_Domain => Always_Delay,
650 Aspect_Dynamic_Predicate => Always_Delay,
651 Aspect_Elaborate_Body => Always_Delay,
652 Aspect_Export => Always_Delay,
653 Aspect_External_Name => Always_Delay,
654 Aspect_External_Tag => Always_Delay,
655 Aspect_Favor_Top_Level => Always_Delay,
656 Aspect_Implicit_Dereference => Always_Delay,
657 Aspect_Import => Always_Delay,
658 Aspect_Independent => Always_Delay,
659 Aspect_Independent_Components => Always_Delay,
660 Aspect_Inline => Always_Delay,
661 Aspect_Inline_Always => Always_Delay,
662 Aspect_Input => Always_Delay,
663 Aspect_Interrupt_Handler => Always_Delay,
664 Aspect_Interrupt_Priority => Always_Delay,
665 Aspect_Invariant => Always_Delay,
666 Aspect_Iterable => Always_Delay,
667 Aspect_Iterator_Element => Always_Delay,
668 Aspect_Link_Name => Always_Delay,
669 Aspect_Linker_Section => Always_Delay,
670 Aspect_Lock_Free => Always_Delay,
671 Aspect_No_Return => Always_Delay,
672 Aspect_Output => Always_Delay,
673 Aspect_Persistent_BSS => Always_Delay,
674 Aspect_Post => Always_Delay,
675 Aspect_Postcondition => Always_Delay,
676 Aspect_Pre => Always_Delay,
677 Aspect_Precondition => Always_Delay,
678 Aspect_Predicate => Always_Delay,
679 Aspect_Preelaborable_Initialization => Always_Delay,
680 Aspect_Preelaborate => Always_Delay,
681 Aspect_Priority => Always_Delay,
682 Aspect_Pure => Always_Delay,
683 Aspect_Pure_Function => Always_Delay,
684 Aspect_Read => Always_Delay,
685 Aspect_Relative_Deadline => Always_Delay,
686 Aspect_Remote_Access_Type => Always_Delay,
687 Aspect_Remote_Call_Interface => Always_Delay,
688 Aspect_Remote_Types => Always_Delay,
689 Aspect_Shared => Always_Delay,
690 Aspect_Shared_Passive => Always_Delay,
691 Aspect_Simple_Storage_Pool => Always_Delay,
692 Aspect_Simple_Storage_Pool_Type => Always_Delay,
693 Aspect_Static_Predicate => Always_Delay,
694 Aspect_Storage_Pool => Always_Delay,
695 Aspect_Stream_Size => Always_Delay,
696 Aspect_Suppress => Always_Delay,
697 Aspect_Suppress_Debug_Info => Always_Delay,
698 Aspect_Suppress_Initialization => Always_Delay,
699 Aspect_Thread_Local_Storage => Always_Delay,
700 Aspect_Type_Invariant => Always_Delay,
701 Aspect_Unchecked_Union => Always_Delay,
702 Aspect_Universal_Aliasing => Always_Delay,
703 Aspect_Universal_Data => Always_Delay,
704 Aspect_Unmodified => Always_Delay,
705 Aspect_Unreferenced => Always_Delay,
706 Aspect_Unreferenced_Objects => Always_Delay,
707 Aspect_Unsuppress => Always_Delay,
708 Aspect_Variable_Indexing => Always_Delay,
709 Aspect_Write => Always_Delay,
711 Aspect_Abstract_State => Never_Delay,
712 Aspect_Annotate => Never_Delay,
713 Aspect_Async_Readers => Never_Delay,
714 Aspect_Async_Writers => Never_Delay,
715 Aspect_Constant_After_Elaboration => Never_Delay,
716 Aspect_Contract_Cases => Never_Delay,
717 Aspect_Convention => Never_Delay,
718 Aspect_Default_Initial_Condition => Never_Delay,
719 Aspect_Depends => Never_Delay,
720 Aspect_Dimension => Never_Delay,
721 Aspect_Dimension_System => Never_Delay,
722 Aspect_Disable_Controlled => Never_Delay,
723 Aspect_Effective_Reads => Never_Delay,
724 Aspect_Effective_Writes => Never_Delay,
725 Aspect_Extensions_Visible => Never_Delay,
726 Aspect_Ghost => Never_Delay,
727 Aspect_Global => Never_Delay,
728 Aspect_Initial_Condition => Never_Delay,
729 Aspect_Initializes => Never_Delay,
730 Aspect_No_Elaboration_Code_All => Never_Delay,
731 Aspect_No_Tagged_Streams => Never_Delay,
732 Aspect_Obsolescent => Never_Delay,
733 Aspect_Part_Of => Never_Delay,
734 Aspect_Refined_Depends => Never_Delay,
735 Aspect_Refined_Global => Never_Delay,
736 Aspect_Refined_Post => Never_Delay,
737 Aspect_Refined_State => Never_Delay,
738 Aspect_SPARK_Mode => Never_Delay,
739 Aspect_Synchronization => Never_Delay,
740 Aspect_Test_Case => Never_Delay,
741 Aspect_Unimplemented => Never_Delay,
742 Aspect_Volatile_Function => Never_Delay,
743 Aspect_Warnings => Never_Delay,
745 Aspect_Alignment => Rep_Aspect,
746 Aspect_Atomic => Rep_Aspect,
747 Aspect_Atomic_Components => Rep_Aspect,
748 Aspect_Bit_Order => Rep_Aspect,
749 Aspect_Component_Size => Rep_Aspect,
750 Aspect_Machine_Radix => Rep_Aspect,
751 Aspect_Object_Size => Rep_Aspect,
752 Aspect_Pack => Rep_Aspect,
753 Aspect_Scalar_Storage_Order => Rep_Aspect,
754 Aspect_Size => Rep_Aspect,
755 Aspect_Small => Rep_Aspect,
756 Aspect_Storage_Size => Rep_Aspect,
757 Aspect_Value_Size => Rep_Aspect,
758 Aspect_Volatile => Rep_Aspect,
759 Aspect_Volatile_Components => Rep_Aspect,
760 Aspect_Volatile_Full_Access => Rep_Aspect);
762 ------------------------------------------------
763 -- Handling of Aspect Specifications on Stubs --
764 ------------------------------------------------
766 -- Aspects that appear on the following stub nodes
768 -- N_Package_Body_Stub
769 -- N_Protected_Body_Stub
770 -- N_Subprogram_Body_Stub
773 -- are treated as if they apply to the corresponding proper body. Their
774 -- analysis is postponed until the analysis of the proper body takes place
775 -- (see Analyze_Proper_Body). The delay is required because the analysis
776 -- may generate extra code which would be harder to relocate to the body.
777 -- If the proper body is present, the aspect specifications are relocated
778 -- to the corresponding body node:
785 -- The subsequent analysis takes care of the aspect-to-pragma conversions
786 -- and verification of pragma legality. In the case where the proper body
787 -- is not available, the aspect specifications are analyzed on the spot
788 -- (see Analyze_Proper_Body) to catch potential errors.
790 -- The following table lists all aspects that can apply to a subprogram
791 -- body [stub]. For instance, the following example is legal:
793 -- package P with SPARK_Mode ...;
794 -- package body P with SPARK_Mode is ...;
796 -- The table should be synchronized with Pragma_On_Body_Or_Stub_OK in unit
797 -- Sem_Prag if the aspects below are implemented by a pragma.
799 Aspect_On_Body_Or_Stub_OK : constant array (Aspect_Id) of Boolean :=
800 (Aspect_Refined_Depends => True,
801 Aspect_Refined_Global => True,
802 Aspect_Refined_Post => True,
803 Aspect_SPARK_Mode => True,
804 Aspect_Warnings => True,
807 ---------------------------------------------------
808 -- Handling of Aspect Specifications in the Tree --
809 ---------------------------------------------------
811 -- Several kinds of declaration node permit aspect specifications in Ada
812 -- 2012 mode. If there was room in all the corresponding declaration nodes,
813 -- we could just have a field Aspect_Specifications pointing to a list of
814 -- nodes for the aspects (N_Aspect_Specification nodes). But there isn't
815 -- room, so we adopt a different approach.
817 -- The following subprograms provide access to a specialized interface
818 -- implemented internally with a hash table in the body, that provides
819 -- access to aspect specifications.
821 function Aspect_Specifications (N : Node_Id) return List_Id;
822 -- Given a node N, returns the list of N_Aspect_Specification nodes that
823 -- are attached to this declaration node. If the node is in the class of
824 -- declaration nodes that permit aspect specifications, as defined by the
825 -- predicate above, and if their Has_Aspects flag is set to True, then this
826 -- will always be a non-empty list. If this flag is set to False, then
827 -- No_List is returned. Normally, the only nodes that have Has_Aspects set
828 -- True are the nodes for which Permits_Aspect_Specifications would return
829 -- True (i.e. the declaration nodes defined in the RM as permitting the
830 -- presence of Aspect_Specifications). However, it is possible for the
831 -- flag Has_Aspects to be set on other nodes as a result of Rewrite and
832 -- Replace calls, and this function may be used to retrieve the aspect
833 -- specifications for the original rewritten node in such cases.
835 function Aspects_On_Body_Or_Stub_OK (N : Node_Id) return Boolean;
836 -- N denotes a body [stub] with aspects. Determine whether all aspects of N
837 -- are allowed to appear on a body [stub].
839 procedure Exchange_Aspects (N1 : Node_Id; N2 : Node_Id);
840 -- Exchange the aspect specifications of two nodes. If either node lacks an
841 -- aspect specification list, the routine has no effect. It is assumed that
842 -- both nodes can support aspects.
844 function Find_Aspect (Id : Entity_Id; A : Aspect_Id) return Node_Id;
845 -- Find the aspect specification of aspect A associated with entity I.
846 -- Return Empty if Id does not have the requested aspect.
848 function Find_Value_Of_Aspect
850 A : Aspect_Id) return Node_Id;
851 -- Find the value of aspect A associated with entity Id. Return Empty if
852 -- Id does not have the requested aspect.
854 function Has_Aspect (Id : Entity_Id; A : Aspect_Id) return Boolean;
855 -- Determine whether entity Id has aspect A
857 procedure Move_Aspects (From : Node_Id; To : Node_Id);
858 -- Relocate the aspect specifications of node From to node To. On entry it
859 -- is assumed that To does not have aspect specifications. If From has no
860 -- aspects, the routine has no effect.
862 procedure Move_Or_Merge_Aspects (From : Node_Id; To : Node_Id);
863 -- Relocate the aspect specifications of node From to node To. If To has
864 -- aspects, the aspects of From are added to the aspects of To. If From has
865 -- no aspects, the routine has no effect. When From denotes a subprogram
866 -- body stub that also acts as a spec, the only aspects relocated to node
867 -- To are those from table Aspect_On_Body_Or_Stub_OK and preconditions.
869 function Permits_Aspect_Specifications (N : Node_Id) return Boolean;
870 -- Returns True if the node N is a declaration node that permits aspect
871 -- specifications in the grammar. It is possible for other nodes to have
872 -- aspect specifications as a result of Rewrite or Replace calls.
874 procedure Remove_Aspects (N : Node_Id);
875 -- Delete the aspect specifications associated with node N. If the node has
876 -- no aspects, the routine has no effect.
878 function Same_Aspect (A1 : Aspect_Id; A2 : Aspect_Id) return Boolean;
879 -- Returns True if A1 and A2 are (essentially) the same aspect. This is not
880 -- a simple equality test because e.g. Post and Postcondition are the same.
881 -- This is used for detecting duplicate aspects.
883 procedure Set_Aspect_Specifications (N : Node_Id; L : List_Id);
884 -- The node N must be in the class of declaration nodes that permit aspect
885 -- specifications and the Has_Aspects flag must be False on entry. L must
886 -- be a non-empty list of N_Aspect_Specification nodes. This procedure sets
887 -- the Has_Aspects flag to True, and makes an entry that can be retrieved
888 -- by a subsequent Aspect_Specifications call. It is an error to call this
889 -- procedure with a node that does not permit aspect specifications, or a
890 -- node that has its Has_Aspects flag set True on entry, or with L being an
891 -- empty list or No_List.
894 -- Reads contents of Aspect_Specifications hash table from the tree file
896 procedure Tree_Write;
897 -- Writes contents of Aspect_Specifications hash table to the tree file
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