1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                              A S P E C T S                               --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 2010-2019, 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.                                     --
17--                                                                          --
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.               --
21--                                                                          --
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/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
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.
36
37------------------------
38-- Adding New Aspects --
39------------------------
40
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.
46
47--  To add a new aspect, you need to do the following
48
49--    1. Create a name in snames.ads-tmpl
50
51--    2. Create a value in type Aspect_Id in this unit
52
53--    3. Add a value for the aspect in the global arrays defined in this unit
54
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
57--       treatments later.
58
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 preanalyzed
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.
66
67with Namet;   use Namet;
68with Snames;  use Snames;
69with Types;   use Types;
70
71package Aspects is
72
73   --  Type defining recognized aspects
74
75   type Aspect_Id is
76     (No_Aspect,                            -- Dummy entry for no aspect
77      Aspect_Abstract_State,                -- GNAT
78      Aspect_Address,
79      Aspect_Alignment,
80      Aspect_Annotate,                      -- GNAT
81      Aspect_Async_Readers,                 -- GNAT
82      Aspect_Async_Writers,                 -- GNAT
83      Aspect_Attach_Handler,
84      Aspect_Bit_Order,
85      Aspect_Component_Size,
86      Aspect_Constant_After_Elaboration,    -- GNAT
87      Aspect_Constant_Indexing,
88      Aspect_Contract_Cases,                -- GNAT
89      Aspect_Convention,
90      Aspect_CPU,
91      Aspect_Default_Component_Value,
92      Aspect_Default_Initial_Condition,     -- GNAT
93      Aspect_Default_Iterator,
94      Aspect_Default_Storage_Pool,
95      Aspect_Default_Value,
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,
105      Aspect_External_Tag,
106      Aspect_Ghost,                         -- GNAT
107      Aspect_Global,                        -- GNAT
108      Aspect_Implicit_Dereference,
109      Aspect_Initial_Condition,             -- GNAT
110      Aspect_Initializes,                   -- GNAT
111      Aspect_Input,
112      Aspect_Interrupt_Priority,
113      Aspect_Invariant,                     -- GNAT
114      Aspect_Iterator_Element,
115      Aspect_Iterable,                      -- GNAT
116      Aspect_Link_Name,
117      Aspect_Linker_Section,                -- GNAT
118      Aspect_Machine_Radix,
119      Aspect_Max_Entry_Queue_Depth,
120      Aspect_Max_Queue_Length,              -- GNAT
121      Aspect_Object_Size,                   -- GNAT
122      Aspect_Obsolescent,                   -- GNAT
123      Aspect_Output,
124      Aspect_Part_Of,                       -- GNAT
125      Aspect_Post,
126      Aspect_Postcondition,
127      Aspect_Pre,
128      Aspect_Precondition,
129      Aspect_Predicate,                     -- GNAT
130      Aspect_Predicate_Failure,
131      Aspect_Priority,
132      Aspect_Read,
133      Aspect_Refined_Depends,               -- GNAT
134      Aspect_Refined_Global,                -- GNAT
135      Aspect_Refined_Post,                  -- GNAT
136      Aspect_Refined_State,                 -- GNAT
137      Aspect_Relative_Deadline,
138      Aspect_Scalar_Storage_Order,          -- GNAT
139      Aspect_Secondary_Stack_Size,          -- GNAT
140      Aspect_Simple_Storage_Pool,           -- GNAT
141      Aspect_Size,
142      Aspect_Small,
143      Aspect_SPARK_Mode,                    -- GNAT
144      Aspect_Static_Predicate,
145      Aspect_Storage_Pool,
146      Aspect_Storage_Size,
147      Aspect_Stream_Size,
148      Aspect_Suppress,
149      Aspect_Synchronization,
150      Aspect_Test_Case,                     -- GNAT
151      Aspect_Type_Invariant,
152      Aspect_Unimplemented,                 -- GNAT
153      Aspect_Unsuppress,
154      Aspect_Value_Size,                    -- GNAT
155      Aspect_Variable_Indexing,
156      Aspect_Volatile_Function,             -- GNAT
157      Aspect_Warnings,                      -- GNAT
158      Aspect_Write,
159
160      --  The following aspects correspond to library unit pragmas
161
162      Aspect_All_Calls_Remote,
163      Aspect_Elaborate_Body,
164      Aspect_No_Elaboration_Code_All,       -- GNAT
165      Aspect_Preelaborate,
166      Aspect_Pure,
167      Aspect_Remote_Call_Interface,
168      Aspect_Remote_Types,
169      Aspect_Shared_Passive,
170      Aspect_Universal_Data,                -- GNAT
171
172      --  Remaining aspects have a static boolean value that turns the aspect
173      --  on or off. They all correspond to pragmas, but are only converted to
174      --  the pragmas where the value is True. A value of False normally means
175      --  that the aspect is ignored, except in the case of derived types where
176      --  the aspect value is inherited from the parent, in which case, we do
177      --  not allow False if we inherit a True value from the parent.
178
179      Aspect_Asynchronous,
180      Aspect_Atomic,
181      Aspect_Atomic_Components,
182      Aspect_Disable_Controlled,            -- GNAT
183      Aspect_Discard_Names,
184      Aspect_Export,
185      Aspect_Favor_Top_Level,               -- GNAT
186      Aspect_Independent,
187      Aspect_Independent_Components,
188      Aspect_Import,
189      Aspect_Inline,
190      Aspect_Inline_Always,                 -- GNAT
191      Aspect_Interrupt_Handler,
192      Aspect_Lock_Free,                     -- GNAT
193      Aspect_No_Inline,                     -- GNAT
194      Aspect_No_Return,
195      Aspect_No_Tagged_Streams,             -- GNAT
196      Aspect_Pack,
197      Aspect_Persistent_BSS,                -- GNAT
198      Aspect_Preelaborable_Initialization,
199      Aspect_Pure_Function,                 -- GNAT
200      Aspect_Remote_Access_Type,            -- GNAT
201      Aspect_Shared,                        -- GNAT (equivalent to Atomic)
202      Aspect_Simple_Storage_Pool_Type,      -- GNAT
203      Aspect_Suppress_Debug_Info,           -- GNAT
204      Aspect_Suppress_Initialization,       -- GNAT
205      Aspect_Thread_Local_Storage,          -- GNAT
206      Aspect_Unchecked_Union,
207      Aspect_Universal_Aliasing,            -- GNAT
208      Aspect_Unmodified,                    -- GNAT
209      Aspect_Unreferenced,                  -- GNAT
210      Aspect_Unreferenced_Objects,          -- GNAT
211      Aspect_Volatile,
212      Aspect_Volatile_Components,
213      Aspect_Volatile_Full_Access);         -- GNAT
214
215   subtype Aspect_Id_Exclude_No_Aspect is
216     Aspect_Id range Aspect_Id'Succ (No_Aspect) .. Aspect_Id'Last;
217   --  Aspect_Id's excluding No_Aspect
218
219   --  The following array indicates aspects that accept 'Class
220
221   Class_Aspect_OK : constant array (Aspect_Id) of Boolean :=
222     (Aspect_Input          => True,
223      Aspect_Invariant      => True,
224      Aspect_Output         => True,
225      Aspect_Pre            => True,
226      Aspect_Predicate      => True,
227      Aspect_Post           => True,
228      Aspect_Read           => True,
229      Aspect_Write          => True,
230      Aspect_Type_Invariant => True,
231      others                => False);
232
233   --  The following array identifies all implementation defined aspects
234
235   Implementation_Defined_Aspect : constant array (Aspect_Id) of Boolean :=
236     (Aspect_Abstract_State             => True,
237      Aspect_Annotate                   => True,
238      Aspect_Async_Readers              => True,
239      Aspect_Async_Writers              => True,
240      Aspect_Constant_After_Elaboration => True,
241      Aspect_Contract_Cases             => True,
242      Aspect_Depends                    => True,
243      Aspect_Dimension                  => True,
244      Aspect_Dimension_System           => True,
245      Aspect_Effective_Reads            => True,
246      Aspect_Effective_Writes           => True,
247      Aspect_Extensions_Visible         => True,
248      Aspect_Favor_Top_Level            => True,
249      Aspect_Ghost                      => True,
250      Aspect_Global                     => True,
251      Aspect_Inline_Always              => True,
252      Aspect_Invariant                  => True,
253      Aspect_Lock_Free                  => True,
254      Aspect_Max_Entry_Queue_Depth      => True,
255      Aspect_Max_Queue_Length           => True,
256      Aspect_Object_Size                => True,
257      Aspect_Persistent_BSS             => True,
258      Aspect_Predicate                  => True,
259      Aspect_Pure_Function              => True,
260      Aspect_Remote_Access_Type         => True,
261      Aspect_Scalar_Storage_Order       => True,
262      Aspect_Secondary_Stack_Size       => True,
263      Aspect_Shared                     => True,
264      Aspect_Simple_Storage_Pool        => True,
265      Aspect_Simple_Storage_Pool_Type   => True,
266      Aspect_Suppress_Debug_Info        => True,
267      Aspect_Suppress_Initialization    => True,
268      Aspect_Thread_Local_Storage       => True,
269      Aspect_Test_Case                  => True,
270      Aspect_Universal_Aliasing         => True,
271      Aspect_Universal_Data             => True,
272      Aspect_Unmodified                 => True,
273      Aspect_Unreferenced               => True,
274      Aspect_Unreferenced_Objects       => True,
275      Aspect_Value_Size                 => True,
276      Aspect_Volatile_Function          => True,
277      Aspect_Warnings                   => True,
278      others                            => False);
279
280   --  The following array indicates aspects for which multiple occurrences of
281   --  the same aspect attached to the same declaration are allowed.
282
283   No_Duplicates_Allowed : constant array (Aspect_Id) of Boolean :=
284     (Aspect_Annotate  => False,
285      Aspect_Test_Case => False,
286      others           => True);
287
288   --  The following subtype defines aspects corresponding to library unit
289   --  pragmas, these can only validly appear as aspects for library units,
290   --  and result in a corresponding pragma being inserted immediately after
291   --  the occurrence of the aspect.
292
293   subtype Library_Unit_Aspects is
294     Aspect_Id range Aspect_All_Calls_Remote .. Aspect_Universal_Data;
295
296   --  The following subtype defines aspects accepting an optional static
297   --  boolean parameter indicating if the aspect should be active or
298   --  cancelling. If the parameter is missing the effective value is True,
299   --  enabling the aspect. If the parameter is present it must be a static
300   --  expression of type Standard.Boolean. If the value is True, then the
301   --  aspect is enabled. If it is False, the aspect is disabled.
302
303   subtype Boolean_Aspects is
304     Aspect_Id range Aspect_Asynchronous .. Aspect_Id'Last;
305
306   subtype Pre_Post_Aspects is
307     Aspect_Id range Aspect_Post .. Aspect_Precondition;
308
309   --  The following type is used for indicating allowed expression forms
310
311   type Aspect_Expression is
312     (Expression,             -- Required expression
313      Name,                   -- Required name
314      Optional_Expression,    -- Optional boolean expression
315      Optional_Name);         -- Optional name
316
317   --  The following array indicates what argument type is required
318
319   Aspect_Argument : constant array (Aspect_Id) of Aspect_Expression :=
320     (No_Aspect                         => Optional_Expression,
321      Aspect_Abstract_State             => Expression,
322      Aspect_Address                    => Expression,
323      Aspect_Alignment                  => Expression,
324      Aspect_Annotate                   => Expression,
325      Aspect_Async_Readers              => Optional_Expression,
326      Aspect_Async_Writers              => Optional_Expression,
327      Aspect_Attach_Handler             => Expression,
328      Aspect_Bit_Order                  => Expression,
329      Aspect_Component_Size             => Expression,
330      Aspect_Constant_After_Elaboration => Optional_Expression,
331      Aspect_Constant_Indexing          => Name,
332      Aspect_Contract_Cases             => Expression,
333      Aspect_Convention                 => Name,
334      Aspect_CPU                        => Expression,
335      Aspect_Default_Component_Value    => Expression,
336      Aspect_Default_Initial_Condition  => Optional_Expression,
337      Aspect_Default_Iterator           => Name,
338      Aspect_Default_Storage_Pool       => Expression,
339      Aspect_Default_Value              => Expression,
340      Aspect_Depends                    => Expression,
341      Aspect_Dimension                  => Expression,
342      Aspect_Dimension_System           => Expression,
343      Aspect_Dispatching_Domain         => Expression,
344      Aspect_Dynamic_Predicate          => Expression,
345      Aspect_Effective_Reads            => Optional_Expression,
346      Aspect_Effective_Writes           => Optional_Expression,
347      Aspect_Extensions_Visible         => Optional_Expression,
348      Aspect_External_Name              => Expression,
349      Aspect_External_Tag               => Expression,
350      Aspect_Ghost                      => Optional_Expression,
351      Aspect_Global                     => Expression,
352      Aspect_Implicit_Dereference       => Name,
353      Aspect_Initial_Condition          => Expression,
354      Aspect_Initializes                => Expression,
355      Aspect_Input                      => Name,
356      Aspect_Interrupt_Priority         => Expression,
357      Aspect_Invariant                  => Expression,
358      Aspect_Iterable                   => Expression,
359      Aspect_Iterator_Element           => Name,
360      Aspect_Link_Name                  => Expression,
361      Aspect_Linker_Section             => Expression,
362      Aspect_Machine_Radix              => Expression,
363      Aspect_Max_Entry_Queue_Depth      => Expression,
364      Aspect_Max_Queue_Length           => Expression,
365      Aspect_Object_Size                => Expression,
366      Aspect_Obsolescent                => Optional_Expression,
367      Aspect_Output                     => Name,
368      Aspect_Part_Of                    => Expression,
369      Aspect_Post                       => Expression,
370      Aspect_Postcondition              => Expression,
371      Aspect_Pre                        => Expression,
372      Aspect_Precondition               => Expression,
373      Aspect_Predicate                  => Expression,
374      Aspect_Predicate_Failure          => Expression,
375      Aspect_Priority                   => Expression,
376      Aspect_Read                       => Name,
377      Aspect_Refined_Depends            => Expression,
378      Aspect_Refined_Global             => Expression,
379      Aspect_Refined_Post               => Expression,
380      Aspect_Refined_State              => Expression,
381      Aspect_Relative_Deadline          => Expression,
382      Aspect_Scalar_Storage_Order       => Expression,
383      Aspect_Secondary_Stack_Size       => Expression,
384      Aspect_Simple_Storage_Pool        => Name,
385      Aspect_Size                       => Expression,
386      Aspect_Small                      => Expression,
387      Aspect_SPARK_Mode                 => Optional_Name,
388      Aspect_Static_Predicate           => Expression,
389      Aspect_Storage_Pool               => Name,
390      Aspect_Storage_Size               => Expression,
391      Aspect_Stream_Size                => Expression,
392      Aspect_Suppress                   => Name,
393      Aspect_Synchronization            => Name,
394      Aspect_Test_Case                  => Expression,
395      Aspect_Type_Invariant             => Expression,
396      Aspect_Unimplemented              => Optional_Expression,
397      Aspect_Unsuppress                 => Name,
398      Aspect_Value_Size                 => Expression,
399      Aspect_Variable_Indexing          => Name,
400      Aspect_Volatile_Function          => Optional_Expression,
401      Aspect_Warnings                   => Name,
402      Aspect_Write                      => Name,
403
404      Boolean_Aspects                   => Optional_Expression,
405      Library_Unit_Aspects              => Optional_Expression);
406
407   -----------------------------------------
408   -- Table Linking Names and Aspect_Id's --
409   -----------------------------------------
410
411   --  Table linking aspect names and id's
412
413   Aspect_Names : constant array (Aspect_Id) of Name_Id :=
414     (No_Aspect                           => No_Name,
415      Aspect_Abstract_State               => Name_Abstract_State,
416      Aspect_Address                      => Name_Address,
417      Aspect_Alignment                    => Name_Alignment,
418      Aspect_All_Calls_Remote             => Name_All_Calls_Remote,
419      Aspect_Annotate                     => Name_Annotate,
420      Aspect_Async_Readers                => Name_Async_Readers,
421      Aspect_Async_Writers                => Name_Async_Writers,
422      Aspect_Asynchronous                 => Name_Asynchronous,
423      Aspect_Atomic                       => Name_Atomic,
424      Aspect_Atomic_Components            => Name_Atomic_Components,
425      Aspect_Attach_Handler               => Name_Attach_Handler,
426      Aspect_Bit_Order                    => Name_Bit_Order,
427      Aspect_Component_Size               => Name_Component_Size,
428      Aspect_Constant_After_Elaboration   => Name_Constant_After_Elaboration,
429      Aspect_Constant_Indexing            => Name_Constant_Indexing,
430      Aspect_Contract_Cases               => Name_Contract_Cases,
431      Aspect_Convention                   => Name_Convention,
432      Aspect_CPU                          => Name_CPU,
433      Aspect_Default_Component_Value      => Name_Default_Component_Value,
434      Aspect_Default_Initial_Condition    => Name_Default_Initial_Condition,
435      Aspect_Default_Iterator             => Name_Default_Iterator,
436      Aspect_Default_Storage_Pool         => Name_Default_Storage_Pool,
437      Aspect_Default_Value                => Name_Default_Value,
438      Aspect_Depends                      => Name_Depends,
439      Aspect_Dimension                    => Name_Dimension,
440      Aspect_Dimension_System             => Name_Dimension_System,
441      Aspect_Disable_Controlled           => Name_Disable_Controlled,
442      Aspect_Discard_Names                => Name_Discard_Names,
443      Aspect_Dispatching_Domain           => Name_Dispatching_Domain,
444      Aspect_Dynamic_Predicate            => Name_Dynamic_Predicate,
445      Aspect_Effective_Reads              => Name_Effective_Reads,
446      Aspect_Effective_Writes             => Name_Effective_Writes,
447      Aspect_Elaborate_Body               => Name_Elaborate_Body,
448      Aspect_Export                       => Name_Export,
449      Aspect_Extensions_Visible           => Name_Extensions_Visible,
450      Aspect_External_Name                => Name_External_Name,
451      Aspect_External_Tag                 => Name_External_Tag,
452      Aspect_Favor_Top_Level              => Name_Favor_Top_Level,
453      Aspect_Ghost                        => Name_Ghost,
454      Aspect_Global                       => Name_Global,
455      Aspect_Implicit_Dereference         => Name_Implicit_Dereference,
456      Aspect_Import                       => Name_Import,
457      Aspect_Independent                  => Name_Independent,
458      Aspect_Independent_Components       => Name_Independent_Components,
459      Aspect_Inline                       => Name_Inline,
460      Aspect_Inline_Always                => Name_Inline_Always,
461      Aspect_Initial_Condition            => Name_Initial_Condition,
462      Aspect_Initializes                  => Name_Initializes,
463      Aspect_Input                        => Name_Input,
464      Aspect_Interrupt_Handler            => Name_Interrupt_Handler,
465      Aspect_Interrupt_Priority           => Name_Interrupt_Priority,
466      Aspect_Invariant                    => Name_Invariant,
467      Aspect_Iterator_Element             => Name_Iterator_Element,
468      Aspect_Iterable                     => Name_Iterable,
469      Aspect_Link_Name                    => Name_Link_Name,
470      Aspect_Linker_Section               => Name_Linker_Section,
471      Aspect_Lock_Free                    => Name_Lock_Free,
472      Aspect_Machine_Radix                => Name_Machine_Radix,
473      Aspect_Max_Entry_Queue_Depth        => Name_Max_Entry_Queue_Depth,
474      Aspect_Max_Queue_Length             => Name_Max_Queue_Length,
475      Aspect_No_Elaboration_Code_All      => Name_No_Elaboration_Code_All,
476      Aspect_No_Inline                    => Name_No_Inline,
477      Aspect_No_Return                    => Name_No_Return,
478      Aspect_No_Tagged_Streams            => Name_No_Tagged_Streams,
479      Aspect_Object_Size                  => Name_Object_Size,
480      Aspect_Obsolescent                  => Name_Obsolescent,
481      Aspect_Output                       => Name_Output,
482      Aspect_Pack                         => Name_Pack,
483      Aspect_Part_Of                      => Name_Part_Of,
484      Aspect_Persistent_BSS               => Name_Persistent_BSS,
485      Aspect_Post                         => Name_Post,
486      Aspect_Postcondition                => Name_Postcondition,
487      Aspect_Pre                          => Name_Pre,
488      Aspect_Precondition                 => Name_Precondition,
489      Aspect_Predicate                    => Name_Predicate,
490      Aspect_Predicate_Failure            => Name_Predicate_Failure,
491      Aspect_Preelaborable_Initialization => Name_Preelaborable_Initialization,
492      Aspect_Preelaborate                 => Name_Preelaborate,
493      Aspect_Priority                     => Name_Priority,
494      Aspect_Pure                         => Name_Pure,
495      Aspect_Pure_Function                => Name_Pure_Function,
496      Aspect_Read                         => Name_Read,
497      Aspect_Refined_Depends              => Name_Refined_Depends,
498      Aspect_Refined_Global               => Name_Refined_Global,
499      Aspect_Refined_Post                 => Name_Refined_Post,
500      Aspect_Refined_State                => Name_Refined_State,
501      Aspect_Relative_Deadline            => Name_Relative_Deadline,
502      Aspect_Remote_Access_Type           => Name_Remote_Access_Type,
503      Aspect_Remote_Call_Interface        => Name_Remote_Call_Interface,
504      Aspect_Remote_Types                 => Name_Remote_Types,
505      Aspect_Scalar_Storage_Order         => Name_Scalar_Storage_Order,
506      Aspect_Secondary_Stack_Size         => Name_Secondary_Stack_Size,
507      Aspect_Shared                       => Name_Shared,
508      Aspect_Shared_Passive               => Name_Shared_Passive,
509      Aspect_Simple_Storage_Pool          => Name_Simple_Storage_Pool,
510      Aspect_Simple_Storage_Pool_Type     => Name_Simple_Storage_Pool_Type,
511      Aspect_Size                         => Name_Size,
512      Aspect_Small                        => Name_Small,
513      Aspect_SPARK_Mode                   => Name_SPARK_Mode,
514      Aspect_Static_Predicate             => Name_Static_Predicate,
515      Aspect_Storage_Pool                 => Name_Storage_Pool,
516      Aspect_Storage_Size                 => Name_Storage_Size,
517      Aspect_Stream_Size                  => Name_Stream_Size,
518      Aspect_Suppress                     => Name_Suppress,
519      Aspect_Suppress_Debug_Info          => Name_Suppress_Debug_Info,
520      Aspect_Suppress_Initialization      => Name_Suppress_Initialization,
521      Aspect_Thread_Local_Storage         => Name_Thread_Local_Storage,
522      Aspect_Synchronization              => Name_Synchronization,
523      Aspect_Test_Case                    => Name_Test_Case,
524      Aspect_Type_Invariant               => Name_Type_Invariant,
525      Aspect_Unchecked_Union              => Name_Unchecked_Union,
526      Aspect_Unimplemented                => Name_Unimplemented,
527      Aspect_Universal_Aliasing           => Name_Universal_Aliasing,
528      Aspect_Universal_Data               => Name_Universal_Data,
529      Aspect_Unmodified                   => Name_Unmodified,
530      Aspect_Unreferenced                 => Name_Unreferenced,
531      Aspect_Unreferenced_Objects         => Name_Unreferenced_Objects,
532      Aspect_Unsuppress                   => Name_Unsuppress,
533      Aspect_Value_Size                   => Name_Value_Size,
534      Aspect_Variable_Indexing            => Name_Variable_Indexing,
535      Aspect_Volatile                     => Name_Volatile,
536      Aspect_Volatile_Components          => Name_Volatile_Components,
537      Aspect_Volatile_Full_Access         => Name_Volatile_Full_Access,
538      Aspect_Volatile_Function            => Name_Volatile_Function,
539      Aspect_Warnings                     => Name_Warnings,
540      Aspect_Write                        => Name_Write);
541
542   function Get_Aspect_Id (Name : Name_Id) return Aspect_Id;
543   pragma Inline (Get_Aspect_Id);
544   --  Given a name Nam, returns the corresponding aspect id value. If the name
545   --  does not match any aspect, then No_Aspect is returned as the result.
546
547   function Get_Aspect_Id (Aspect : Node_Id) return Aspect_Id;
548   pragma Inline (Get_Aspect_Id);
549   --  Given an aspect specification, return the corresponding aspect_id value.
550   --  If the name does not match any aspect, return No_Aspect.
551
552   ------------------------------------
553   -- Delaying Evaluation of Aspects --
554   ------------------------------------
555
556   --  The RM requires that all language defined aspects taking an expression
557   --  delay evaluation of the expression till the freeze point of the entity
558   --  to which the aspect applies. This allows forward references, and is of
559   --  use for example in connection with preconditions and postconditions
560   --  where the requirement of making all references in contracts to local
561   --  functions be backwards references would be onerous.
562
563   --  For consistency, even attributes like Size are delayed, so we can do:
564
565   --    type A is range 1 .. 10
566   --      with Size => Not_Defined_Yet;
567   --    ..
568   --    Not_Defined_Yet : constant := 64;
569
570   --  Resulting in A having a size of 64, which gets set when A is frozen.
571   --  Furthermore, we can have a situation like
572
573   --    type A is range 1 .. 10
574   --      with Size => Not_Defined_Yet;
575   --    ..
576   --    type B is new A;
577   --    ..
578   --    Not_Defined_Yet : constant := 64;
579
580   --  where the Size of A is considered to have been previously specified at
581   --  the point of derivation, even though the actual value of the size is
582   --  not known yet, and in this example B inherits the size value of 64.
583
584   --  Our normal implementation model (prior to Ada 2012) was simply to copy
585   --  inheritable attributes at the point of derivation. Then any subsequent
586   --  representation items apply either to the parent type, not affecting the
587   --  derived type, or to the derived type, not affecting the parent type.
588
589   --  To deal with the delayed aspect case, we use two flags. The first is
590   --  set on the parent type if it has delayed representation aspects. This
591   --  flag Has_Delayed_Rep_Aspects indicates that if we derive from this type
592   --  we have to worry about making sure we inherit any delayed aspects. The
593   --  second flag is set on a derived type: May_Have_Inherited_Rep_Aspects
594   --  is set if the parent type has Has_Delayed_Rep_Aspects set.
595
596   --  When we freeze a derived type, if the May_Have_Inherited_Rep_Aspects
597   --  flag is set, then we call Freeze.Inherit_Delayed_Rep_Aspects when
598   --  the derived type is frozen, which deals with the necessary copying of
599   --  information from the parent type, which must be frozen at that point
600   --  (since freezing the derived type first freezes the parent type).
601
602   --  SPARK 2014 aspects do not follow the general delay mechanism as they
603   --  act as annotations and cannot modify the attributes of their related
604   --  constructs. To handle forward references in such aspects, the compiler
605   --  delays the analysis of their respective pragmas by collecting them in
606   --  N_Contract nodes. The pragmas are then analyzed at the end of the
607   --  declarative region containing the related construct. For details,
608   --  see routines Analyze_xxx_In_Decl_Part.
609
610   --  The following shows which aspects are delayed. There are three cases:
611
612   type Delay_Type is
613     (Always_Delay,
614      --  This aspect is not a representation aspect that can be inherited and
615      --  is always delayed, as required by the language definition.
616
617      Never_Delay,
618      --  There are two cases. There are language defined aspects like
619      --  Convention where the "expression" is simply an uninterpreted
620      --  identifier, and there is no issue of evaluating it and thus no
621      --  issue of delaying the evaluation. The second case is implementation
622      --  defined aspects where we have decided that we don't want to allow
623      --  delays (and for our own aspects we can do what we like).
624
625      Rep_Aspect);
626      --  These are the cases of representation aspects that are in general
627      --  delayed, and where there is a potential issue of derived types that
628      --  inherit delayed representation values.
629
630   --  Note: even if this table indicates that an aspect is delayed, we never
631   --  delay Boolean aspects that have a missing expression (taken as True),
632   --  or expressions for delayed rep items that consist of an integer literal
633   --  (most cases of Size etc. in practice), since in these cases we know we
634   --  can get the value of the expression without delay. Note that we still
635   --  need to delay Boolean aspects that are specifically set to True:
636
637   --     type R is array (0 .. 31) of Boolean
638   --       with Pack => True;
639   --     True : constant Boolean := False;
640
641   --  This is nonsense, but we need to make it work and result in R not
642   --  being packed, and if we have something like:
643
644   --     type R is array (0 .. 31) of Boolean
645   --       with Pack => True;
646   --     RR : R;
647   --     True : constant Boolean := False;
648
649   --  This is illegal because the visibility of True changes after the freeze
650   --  point, which is not allowed, and we need the delay mechanism to properly
651   --  diagnose this error.
652
653   Aspect_Delay : constant array (Aspect_Id) of Delay_Type :=
654     (No_Aspect                           => Always_Delay,
655      Aspect_Address                      => Always_Delay,
656      Aspect_All_Calls_Remote             => Always_Delay,
657      Aspect_Asynchronous                 => Always_Delay,
658      Aspect_Attach_Handler               => Always_Delay,
659      Aspect_Constant_Indexing            => Always_Delay,
660      Aspect_CPU                          => Always_Delay,
661      Aspect_Default_Iterator             => Always_Delay,
662      Aspect_Default_Storage_Pool         => Always_Delay,
663      Aspect_Default_Value                => Always_Delay,
664      Aspect_Default_Component_Value      => Always_Delay,
665      Aspect_Discard_Names                => Always_Delay,
666      Aspect_Dispatching_Domain           => Always_Delay,
667      Aspect_Dynamic_Predicate            => Always_Delay,
668      Aspect_Elaborate_Body               => Always_Delay,
669      Aspect_External_Name                => Always_Delay,
670      Aspect_External_Tag                 => Always_Delay,
671      Aspect_Favor_Top_Level              => Always_Delay,
672      Aspect_Implicit_Dereference         => Always_Delay,
673      Aspect_Independent                  => Always_Delay,
674      Aspect_Independent_Components       => Always_Delay,
675      Aspect_Inline                       => Always_Delay,
676      Aspect_Inline_Always                => Always_Delay,
677      Aspect_Input                        => Always_Delay,
678      Aspect_Interrupt_Handler            => Always_Delay,
679      Aspect_Interrupt_Priority           => Always_Delay,
680      Aspect_Invariant                    => Always_Delay,
681      Aspect_Iterable                     => Always_Delay,
682      Aspect_Iterator_Element             => Always_Delay,
683      Aspect_Link_Name                    => Always_Delay,
684      Aspect_Linker_Section               => Always_Delay,
685      Aspect_Lock_Free                    => Always_Delay,
686      Aspect_No_Inline                    => Always_Delay,
687      Aspect_No_Return                    => Always_Delay,
688      Aspect_Output                       => Always_Delay,
689      Aspect_Persistent_BSS               => Always_Delay,
690      Aspect_Post                         => Always_Delay,
691      Aspect_Postcondition                => Always_Delay,
692      Aspect_Pre                          => Always_Delay,
693      Aspect_Precondition                 => Always_Delay,
694      Aspect_Predicate                    => Always_Delay,
695      Aspect_Predicate_Failure            => Always_Delay,
696      Aspect_Preelaborable_Initialization => Always_Delay,
697      Aspect_Preelaborate                 => Always_Delay,
698      Aspect_Priority                     => Always_Delay,
699      Aspect_Pure                         => Always_Delay,
700      Aspect_Pure_Function                => Always_Delay,
701      Aspect_Read                         => Always_Delay,
702      Aspect_Relative_Deadline            => Always_Delay,
703      Aspect_Remote_Access_Type           => Always_Delay,
704      Aspect_Remote_Call_Interface        => Always_Delay,
705      Aspect_Remote_Types                 => Always_Delay,
706      Aspect_Secondary_Stack_Size         => Always_Delay,
707      Aspect_Shared                       => Always_Delay,
708      Aspect_Shared_Passive               => Always_Delay,
709      Aspect_Simple_Storage_Pool          => Always_Delay,
710      Aspect_Simple_Storage_Pool_Type     => Always_Delay,
711      Aspect_Static_Predicate             => Always_Delay,
712      Aspect_Storage_Pool                 => Always_Delay,
713      Aspect_Stream_Size                  => Always_Delay,
714      Aspect_Suppress                     => Always_Delay,
715      Aspect_Suppress_Debug_Info          => Always_Delay,
716      Aspect_Suppress_Initialization      => Always_Delay,
717      Aspect_Thread_Local_Storage         => Always_Delay,
718      Aspect_Type_Invariant               => Always_Delay,
719      Aspect_Unchecked_Union              => Always_Delay,
720      Aspect_Universal_Aliasing           => Always_Delay,
721      Aspect_Universal_Data               => Always_Delay,
722      Aspect_Unmodified                   => Always_Delay,
723      Aspect_Unreferenced                 => Always_Delay,
724      Aspect_Unreferenced_Objects         => Always_Delay,
725      Aspect_Unsuppress                   => Always_Delay,
726      Aspect_Variable_Indexing            => Always_Delay,
727      Aspect_Write                        => Always_Delay,
728
729      Aspect_Abstract_State               => Never_Delay,
730      Aspect_Annotate                     => Never_Delay,
731      Aspect_Async_Readers                => Never_Delay,
732      Aspect_Async_Writers                => Never_Delay,
733      Aspect_Constant_After_Elaboration   => Never_Delay,
734      Aspect_Contract_Cases               => Never_Delay,
735      Aspect_Convention                   => Never_Delay,
736      Aspect_Default_Initial_Condition    => Never_Delay,
737      Aspect_Depends                      => Never_Delay,
738      Aspect_Dimension                    => Never_Delay,
739      Aspect_Dimension_System             => Never_Delay,
740      Aspect_Disable_Controlled           => Never_Delay,
741      Aspect_Effective_Reads              => Never_Delay,
742      Aspect_Effective_Writes             => Never_Delay,
743      Aspect_Export                       => Never_Delay,
744      Aspect_Extensions_Visible           => Never_Delay,
745      Aspect_Ghost                        => Never_Delay,
746      Aspect_Global                       => Never_Delay,
747      Aspect_Import                       => Never_Delay,
748      Aspect_Initial_Condition            => Never_Delay,
749      Aspect_Initializes                  => Never_Delay,
750      Aspect_Max_Entry_Queue_Depth        => Never_Delay,
751      Aspect_Max_Queue_Length             => Never_Delay,
752      Aspect_No_Elaboration_Code_All      => Never_Delay,
753      Aspect_No_Tagged_Streams            => Never_Delay,
754      Aspect_Obsolescent                  => Never_Delay,
755      Aspect_Part_Of                      => Never_Delay,
756      Aspect_Refined_Depends              => Never_Delay,
757      Aspect_Refined_Global               => Never_Delay,
758      Aspect_Refined_Post                 => Never_Delay,
759      Aspect_Refined_State                => Never_Delay,
760      Aspect_SPARK_Mode                   => Never_Delay,
761      Aspect_Synchronization              => Never_Delay,
762      Aspect_Test_Case                    => Never_Delay,
763      Aspect_Unimplemented                => Never_Delay,
764      Aspect_Volatile_Function            => Never_Delay,
765      Aspect_Warnings                     => Never_Delay,
766
767      Aspect_Alignment                    => Rep_Aspect,
768      Aspect_Atomic                       => Rep_Aspect,
769      Aspect_Atomic_Components            => Rep_Aspect,
770      Aspect_Bit_Order                    => Rep_Aspect,
771      Aspect_Component_Size               => Rep_Aspect,
772      Aspect_Machine_Radix                => Rep_Aspect,
773      Aspect_Object_Size                  => Rep_Aspect,
774      Aspect_Pack                         => Rep_Aspect,
775      Aspect_Scalar_Storage_Order         => Rep_Aspect,
776      Aspect_Size                         => Rep_Aspect,
777      Aspect_Small                        => Rep_Aspect,
778      Aspect_Storage_Size                 => Rep_Aspect,
779      Aspect_Value_Size                   => Rep_Aspect,
780      Aspect_Volatile                     => Rep_Aspect,
781      Aspect_Volatile_Components          => Rep_Aspect,
782      Aspect_Volatile_Full_Access         => Rep_Aspect);
783
784   ------------------------------------------------
785   -- Handling of Aspect Specifications on Stubs --
786   ------------------------------------------------
787
788   --  Aspects that appear on the following stub nodes
789
790   --    N_Package_Body_Stub
791   --    N_Protected_Body_Stub
792   --    N_Subprogram_Body_Stub
793   --    N_Task_Body_Stub
794
795   --  are treated as if they apply to the corresponding proper body. Their
796   --  analysis is postponed until the analysis of the proper body takes place
797   --  (see Analyze_Proper_Body). The delay is required because the analysis
798   --  may generate extra code which would be harder to relocate to the body.
799   --  If the proper body is present, the aspect specifications are relocated
800   --  to the corresponding body node:
801
802   --    N_Package_Body
803   --    N_Protected_Body
804   --    N_Subprogram_Body
805   --    N_Task_Body
806
807   --  The subsequent analysis takes care of the aspect-to-pragma conversions
808   --  and verification of pragma legality. In the case where the proper body
809   --  is not available, the aspect specifications are analyzed on the spot
810   --  (see Analyze_Proper_Body) to catch potential errors.
811
812   --  The following table lists all aspects that can apply to a subprogram
813   --  body [stub]. For instance, the following example is legal:
814
815   --    package P with SPARK_Mode ...;
816   --    package body P with SPARK_Mode is ...;
817
818   --  The table should be synchronized with Pragma_On_Body_Or_Stub_OK in unit
819   --  Sem_Prag.
820
821   Aspect_On_Body_Or_Stub_OK : constant array (Aspect_Id) of Boolean :=
822     (Aspect_Refined_Depends              => True,
823      Aspect_Refined_Global               => True,
824      Aspect_Refined_Post                 => True,
825      Aspect_SPARK_Mode                   => True,
826      Aspect_Warnings                     => True,
827      others                              => False);
828
829   -------------------------------------------------------------------
830   -- Handling of Aspects Specifications on Single Concurrent Types --
831   -------------------------------------------------------------------
832
833   --  Certain aspects that appear on the following nodes
834
835   --    N_Single_Protected_Declaration
836   --    N_Single_Task_Declaration
837
838   --  are treated as if they apply to the anonymous object produced by the
839   --  analysis of a single concurrent type. The following table lists all
840   --  aspects that should apply to the anonymous object. The table should
841   --  be synchronized with Pragma_On_Anonymous_Object_OK in unit Sem_Prag.
842
843   Aspect_On_Anonymous_Object_OK : constant array (Aspect_Id) of Boolean :=
844     (Aspect_Depends                      => True,
845      Aspect_Global                       => True,
846      Aspect_Part_Of                      => True,
847      others                              => False);
848
849   ---------------------------------------------------
850   -- Handling of Aspect Specifications in the Tree --
851   ---------------------------------------------------
852
853   --  Several kinds of declaration node permit aspect specifications in Ada
854   --  2012 mode. If there was room in all the corresponding declaration nodes,
855   --  we could just have a field Aspect_Specifications pointing to a list of
856   --  nodes for the aspects (N_Aspect_Specification nodes). But there isn't
857   --  room, so we adopt a different approach.
858
859   --  The following subprograms provide access to a specialized interface
860   --  implemented internally with a hash table in the body, that provides
861   --  access to aspect specifications.
862
863   function Aspect_Specifications (N : Node_Id) return List_Id;
864   --  Given a node N, returns the list of N_Aspect_Specification nodes that
865   --  are attached to this declaration node. If the node is in the class of
866   --  declaration nodes that permit aspect specifications, as defined by the
867   --  predicate above, and if their Has_Aspects flag is set to True, then this
868   --  will always be a non-empty list. If this flag is set to False, then
869   --  No_List is returned. Normally, the only nodes that have Has_Aspects set
870   --  True are the nodes for which Permits_Aspect_Specifications would return
871   --  True (i.e. the declaration nodes defined in the RM as permitting the
872   --  presence of Aspect_Specifications). However, it is possible for the
873   --  flag Has_Aspects to be set on other nodes as a result of Rewrite and
874   --  Replace calls, and this function may be used to retrieve the aspect
875   --  specifications for the original rewritten node in such cases.
876
877   function Aspects_On_Body_Or_Stub_OK (N : Node_Id) return Boolean;
878   --  N denotes a body [stub] with aspects. Determine whether all aspects of N
879   --  are allowed to appear on a body [stub].
880
881   procedure Exchange_Aspects (N1 : Node_Id; N2 : Node_Id);
882   --  Exchange the aspect specifications of two nodes. If either node lacks an
883   --  aspect specification list, the routine has no effect. It is assumed that
884   --  both nodes can support aspects.
885
886   function Find_Aspect (Id : Entity_Id; A : Aspect_Id) return Node_Id;
887   --  Find the aspect specification of aspect A associated with entity I.
888   --  Return Empty if Id does not have the requested aspect.
889
890   function Find_Value_Of_Aspect
891     (Id : Entity_Id;
892      A  : Aspect_Id) return Node_Id;
893   --  Find the value of aspect A associated with entity Id. Return Empty if
894   --  Id does not have the requested aspect.
895
896   function Has_Aspect (Id : Entity_Id; A : Aspect_Id) return Boolean;
897   --  Determine whether entity Id has aspect A
898
899   procedure Move_Aspects (From : Node_Id; To : Node_Id);
900   --  Relocate the aspect specifications of node From to node To. On entry it
901   --  is assumed that To does not have aspect specifications. If From has no
902   --  aspects, the routine has no effect.
903
904   procedure Move_Or_Merge_Aspects (From : Node_Id; To : Node_Id);
905   --  Relocate the aspect specifications of node From to node To. If To has
906   --  aspects, the aspects of From are appended to the aspects of To. If From
907   --  has no aspects, the routine has no effect. Special behavior:
908   --    * When node From denotes a subprogram body stub without a previous
909   --      declaration, the only aspects relocated to node To are those found
910   --      in table Aspect_On_Body_Or_Stub_OK.
911   --    * When node From denotes a single synchronized type declaration, the
912   --      only aspects relocated to node To are those found in table
913   --      Aspect_On_Anonymous_Object_OK.
914
915   function Permits_Aspect_Specifications (N : Node_Id) return Boolean;
916   --  Returns True if the node N is a declaration node that permits aspect
917   --  specifications in the grammar. It is possible for other nodes to have
918   --  aspect specifications as a result of Rewrite or Replace calls.
919
920   procedure Remove_Aspects (N : Node_Id);
921   --  Delete the aspect specifications associated with node N. If the node has
922   --  no aspects, the routine has no effect.
923
924   function Same_Aspect (A1 : Aspect_Id; A2 : Aspect_Id) return Boolean;
925   --  Returns True if A1 and A2 are (essentially) the same aspect. This is not
926   --  a simple equality test because e.g. Post and Postcondition are the same.
927   --  This is used for detecting duplicate aspects.
928
929   procedure Set_Aspect_Specifications (N : Node_Id; L : List_Id);
930   --  The node N must be in the class of declaration nodes that permit aspect
931   --  specifications and the Has_Aspects flag must be False on entry. L must
932   --  be a non-empty list of N_Aspect_Specification nodes. This procedure sets
933   --  the Has_Aspects flag to True, and makes an entry that can be retrieved
934   --  by a subsequent Aspect_Specifications call. It is an error to call this
935   --  procedure with a node that does not permit aspect specifications, or a
936   --  node that has its Has_Aspects flag set True on entry, or with L being an
937   --  empty list or No_List.
938
939   procedure Tree_Read;
940   --  Reads contents of Aspect_Specifications hash table from the tree file
941
942   procedure Tree_Write;
943   --  Writes contents of Aspect_Specifications hash table to the tree file
944
945end Aspects;
946