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,         -- GNAT
120      Aspect_Max_Entry_Queue_Length,
121      Aspect_Max_Queue_Length,              -- GNAT
122      Aspect_No_Caching,                    -- GNAT
123      Aspect_Object_Size,                   -- GNAT
124      Aspect_Obsolescent,                   -- GNAT
125      Aspect_Output,
126      Aspect_Part_Of,                       -- GNAT
127      Aspect_Post,
128      Aspect_Postcondition,
129      Aspect_Pre,
130      Aspect_Precondition,
131      Aspect_Predicate,                     -- GNAT
132      Aspect_Predicate_Failure,
133      Aspect_Priority,
134      Aspect_Read,
135      Aspect_Refined_Depends,               -- GNAT
136      Aspect_Refined_Global,                -- GNAT
137      Aspect_Refined_Post,                  -- GNAT
138      Aspect_Refined_State,                 -- GNAT
139      Aspect_Relative_Deadline,
140      Aspect_Scalar_Storage_Order,          -- GNAT
141      Aspect_Secondary_Stack_Size,          -- GNAT
142      Aspect_Simple_Storage_Pool,           -- GNAT
143      Aspect_Size,
144      Aspect_Small,
145      Aspect_SPARK_Mode,                    -- GNAT
146      Aspect_Static_Predicate,
147      Aspect_Storage_Pool,
148      Aspect_Storage_Size,
149      Aspect_Stream_Size,
150      Aspect_Suppress,
151      Aspect_Synchronization,
152      Aspect_Test_Case,                     -- GNAT
153      Aspect_Type_Invariant,
154      Aspect_Unimplemented,                 -- GNAT
155      Aspect_Unsuppress,
156      Aspect_Value_Size,                    -- GNAT
157      Aspect_Variable_Indexing,
158      Aspect_Volatile_Function,             -- GNAT
159      Aspect_Warnings,                      -- GNAT
160      Aspect_Write,
161
162      --  The following aspects correspond to library unit pragmas
163
164      Aspect_All_Calls_Remote,
165      Aspect_Elaborate_Body,
166      Aspect_No_Elaboration_Code_All,       -- GNAT
167      Aspect_Preelaborate,
168      Aspect_Pure,
169      Aspect_Remote_Call_Interface,
170      Aspect_Remote_Types,
171      Aspect_Shared_Passive,
172      Aspect_Universal_Data,                -- GNAT
173
174      --  Remaining aspects have a static boolean value that turns the aspect
175      --  on or off. They all correspond to pragmas, but are only converted to
176      --  the pragmas where the value is True. A value of False normally means
177      --  that the aspect is ignored, except in the case of derived types where
178      --  the aspect value is inherited from the parent, in which case, we do
179      --  not allow False if we inherit a True value from the parent.
180
181      Aspect_Asynchronous,
182      Aspect_Atomic,
183      Aspect_Atomic_Components,
184      Aspect_Disable_Controlled,            -- GNAT
185      Aspect_Discard_Names,
186      Aspect_Export,
187      Aspect_Favor_Top_Level,               -- GNAT
188      Aspect_Independent,
189      Aspect_Independent_Components,
190      Aspect_Import,
191      Aspect_Inline,
192      Aspect_Inline_Always,                 -- GNAT
193      Aspect_Interrupt_Handler,
194      Aspect_Lock_Free,                     -- GNAT
195      Aspect_No_Inline,                     -- GNAT
196      Aspect_No_Return,
197      Aspect_No_Tagged_Streams,             -- GNAT
198      Aspect_Pack,
199      Aspect_Persistent_BSS,                -- GNAT
200      Aspect_Preelaborable_Initialization,
201      Aspect_Pure_Function,                 -- GNAT
202      Aspect_Remote_Access_Type,            -- GNAT
203      Aspect_Shared,                        -- GNAT (equivalent to Atomic)
204      Aspect_Simple_Storage_Pool_Type,      -- GNAT
205      Aspect_Suppress_Debug_Info,           -- GNAT
206      Aspect_Suppress_Initialization,       -- GNAT
207      Aspect_Thread_Local_Storage,          -- GNAT
208      Aspect_Unchecked_Union,
209      Aspect_Universal_Aliasing,            -- GNAT
210      Aspect_Unmodified,                    -- GNAT
211      Aspect_Unreferenced,                  -- GNAT
212      Aspect_Unreferenced_Objects,          -- GNAT
213      Aspect_Volatile,
214      Aspect_Volatile_Components,
215      Aspect_Volatile_Full_Access);         -- GNAT
216
217   subtype Aspect_Id_Exclude_No_Aspect is
218     Aspect_Id range Aspect_Id'Succ (No_Aspect) .. Aspect_Id'Last;
219   --  Aspect_Id's excluding No_Aspect
220
221   --  The following array indicates aspects that accept 'Class
222
223   Class_Aspect_OK : constant array (Aspect_Id) of Boolean :=
224     (Aspect_Input          => True,
225      Aspect_Invariant      => True,
226      Aspect_Output         => True,
227      Aspect_Pre            => True,
228      Aspect_Predicate      => True,
229      Aspect_Post           => True,
230      Aspect_Read           => True,
231      Aspect_Write          => True,
232      Aspect_Type_Invariant => True,
233      others                => False);
234
235   --  The following array identifies all implementation defined aspects
236
237   Implementation_Defined_Aspect : constant array (Aspect_Id) of Boolean :=
238     (Aspect_Abstract_State             => True,
239      Aspect_Annotate                   => True,
240      Aspect_Async_Readers              => True,
241      Aspect_Async_Writers              => True,
242      Aspect_Constant_After_Elaboration => True,
243      Aspect_Contract_Cases             => True,
244      Aspect_Depends                    => True,
245      Aspect_Dimension                  => True,
246      Aspect_Dimension_System           => True,
247      Aspect_Effective_Reads            => True,
248      Aspect_Effective_Writes           => True,
249      Aspect_Extensions_Visible         => True,
250      Aspect_Favor_Top_Level            => True,
251      Aspect_Ghost                      => True,
252      Aspect_Global                     => True,
253      Aspect_Inline_Always              => True,
254      Aspect_Invariant                  => True,
255      Aspect_Lock_Free                  => True,
256      Aspect_Max_Entry_Queue_Depth      => True,
257      Aspect_Max_Entry_Queue_Length     => True,
258      Aspect_Max_Queue_Length           => True,
259      Aspect_Object_Size                => True,
260      Aspect_Persistent_BSS             => True,
261      Aspect_Predicate                  => True,
262      Aspect_Pure_Function              => True,
263      Aspect_Remote_Access_Type         => True,
264      Aspect_Scalar_Storage_Order       => True,
265      Aspect_Secondary_Stack_Size       => True,
266      Aspect_Shared                     => True,
267      Aspect_Simple_Storage_Pool        => True,
268      Aspect_Simple_Storage_Pool_Type   => True,
269      Aspect_Suppress_Debug_Info        => True,
270      Aspect_Suppress_Initialization    => True,
271      Aspect_Thread_Local_Storage       => True,
272      Aspect_Test_Case                  => True,
273      Aspect_Universal_Aliasing         => True,
274      Aspect_Universal_Data             => True,
275      Aspect_Unmodified                 => True,
276      Aspect_Unreferenced               => True,
277      Aspect_Unreferenced_Objects       => True,
278      Aspect_Value_Size                 => True,
279      Aspect_Volatile_Function          => True,
280      Aspect_Warnings                   => True,
281      others                            => False);
282
283   --  The following array indicates aspects that specify operational
284   --  characteristics, and thus are view-specific. Representation
285   --  aspects break privacy, as they are needed during expansion and
286   --  code generation.
287   --  List is currently incomplete ???
288
289   Operational_Aspect : constant array (Aspect_Id) of Boolean :=
290     (Aspect_Constant_Indexing          => True,
291      Aspect_Default_Iterator           => True,
292      Aspect_Iterator_Element           => True,
293      Aspect_Iterable                   => True,
294      Aspect_Variable_Indexing          => True,
295      others                            => False);
296
297   --  The following array indicates aspects for which multiple occurrences of
298   --  the same aspect attached to the same declaration are allowed.
299
300   No_Duplicates_Allowed : constant array (Aspect_Id) of Boolean :=
301     (Aspect_Annotate  => False,
302      Aspect_Test_Case => False,
303      others           => True);
304
305   --  The following subtype defines aspects corresponding to library unit
306   --  pragmas, these can only validly appear as aspects for library units,
307   --  and result in a corresponding pragma being inserted immediately after
308   --  the occurrence of the aspect.
309
310   subtype Library_Unit_Aspects is
311     Aspect_Id range Aspect_All_Calls_Remote .. Aspect_Universal_Data;
312
313   --  The following subtype defines aspects accepting an optional static
314   --  boolean parameter indicating if the aspect should be active or
315   --  cancelling. If the parameter is missing the effective value is True,
316   --  enabling the aspect. If the parameter is present it must be a static
317   --  expression of type Standard.Boolean. If the value is True, then the
318   --  aspect is enabled. If it is False, the aspect is disabled.
319
320   subtype Boolean_Aspects is
321     Aspect_Id range Aspect_Asynchronous .. Aspect_Id'Last;
322
323   subtype Pre_Post_Aspects is
324     Aspect_Id range Aspect_Post .. Aspect_Precondition;
325
326   --  The following type is used for indicating allowed expression forms
327
328   type Aspect_Expression is
329     (Expression,             -- Required expression
330      Name,                   -- Required name
331      Optional_Expression,    -- Optional boolean expression
332      Optional_Name);         -- Optional name
333
334   --  The following array indicates what argument type is required
335
336   Aspect_Argument : constant array (Aspect_Id) of Aspect_Expression :=
337     (No_Aspect                         => Optional_Expression,
338      Aspect_Abstract_State             => Expression,
339      Aspect_Address                    => Expression,
340      Aspect_Alignment                  => Expression,
341      Aspect_Annotate                   => Expression,
342      Aspect_Async_Readers              => Optional_Expression,
343      Aspect_Async_Writers              => Optional_Expression,
344      Aspect_Attach_Handler             => Expression,
345      Aspect_Bit_Order                  => Expression,
346      Aspect_Component_Size             => Expression,
347      Aspect_Constant_After_Elaboration => Optional_Expression,
348      Aspect_Constant_Indexing          => Name,
349      Aspect_Contract_Cases             => Expression,
350      Aspect_Convention                 => Name,
351      Aspect_CPU                        => Expression,
352      Aspect_Default_Component_Value    => Expression,
353      Aspect_Default_Initial_Condition  => Optional_Expression,
354      Aspect_Default_Iterator           => Name,
355      Aspect_Default_Storage_Pool       => Expression,
356      Aspect_Default_Value              => Expression,
357      Aspect_Depends                    => Expression,
358      Aspect_Dimension                  => Expression,
359      Aspect_Dimension_System           => Expression,
360      Aspect_Dispatching_Domain         => Expression,
361      Aspect_Dynamic_Predicate          => Expression,
362      Aspect_Effective_Reads            => Optional_Expression,
363      Aspect_Effective_Writes           => Optional_Expression,
364      Aspect_Extensions_Visible         => Optional_Expression,
365      Aspect_External_Name              => Expression,
366      Aspect_External_Tag               => Expression,
367      Aspect_Ghost                      => Optional_Expression,
368      Aspect_Global                     => Expression,
369      Aspect_Implicit_Dereference       => Name,
370      Aspect_Initial_Condition          => Expression,
371      Aspect_Initializes                => Expression,
372      Aspect_Input                      => Name,
373      Aspect_Interrupt_Priority         => Expression,
374      Aspect_Invariant                  => Expression,
375      Aspect_Iterable                   => Expression,
376      Aspect_Iterator_Element           => Name,
377      Aspect_Link_Name                  => Expression,
378      Aspect_Linker_Section             => Expression,
379      Aspect_Machine_Radix              => Expression,
380      Aspect_Max_Entry_Queue_Depth      => Expression,
381      Aspect_Max_Entry_Queue_Length     => Expression,
382      Aspect_Max_Queue_Length           => Expression,
383      Aspect_No_Caching                 => Optional_Expression,
384      Aspect_Object_Size                => Expression,
385      Aspect_Obsolescent                => Optional_Expression,
386      Aspect_Output                     => Name,
387      Aspect_Part_Of                    => Expression,
388      Aspect_Post                       => Expression,
389      Aspect_Postcondition              => Expression,
390      Aspect_Pre                        => Expression,
391      Aspect_Precondition               => Expression,
392      Aspect_Predicate                  => Expression,
393      Aspect_Predicate_Failure          => Expression,
394      Aspect_Priority                   => Expression,
395      Aspect_Read                       => Name,
396      Aspect_Refined_Depends            => Expression,
397      Aspect_Refined_Global             => Expression,
398      Aspect_Refined_Post               => Expression,
399      Aspect_Refined_State              => Expression,
400      Aspect_Relative_Deadline          => Expression,
401      Aspect_Scalar_Storage_Order       => Expression,
402      Aspect_Secondary_Stack_Size       => Expression,
403      Aspect_Simple_Storage_Pool        => Name,
404      Aspect_Size                       => Expression,
405      Aspect_Small                      => Expression,
406      Aspect_SPARK_Mode                 => Optional_Name,
407      Aspect_Static_Predicate           => Expression,
408      Aspect_Storage_Pool               => Name,
409      Aspect_Storage_Size               => Expression,
410      Aspect_Stream_Size                => Expression,
411      Aspect_Suppress                   => Name,
412      Aspect_Synchronization            => Name,
413      Aspect_Test_Case                  => Expression,
414      Aspect_Type_Invariant             => Expression,
415      Aspect_Unimplemented              => Optional_Expression,
416      Aspect_Unsuppress                 => Name,
417      Aspect_Value_Size                 => Expression,
418      Aspect_Variable_Indexing          => Name,
419      Aspect_Volatile_Function          => Optional_Expression,
420      Aspect_Warnings                   => Name,
421      Aspect_Write                      => Name,
422
423      Boolean_Aspects                   => Optional_Expression,
424      Library_Unit_Aspects              => Optional_Expression);
425
426   -----------------------------------------
427   -- Table Linking Names and Aspect_Id's --
428   -----------------------------------------
429
430   --  Table linking aspect names and id's
431
432   Aspect_Names : constant array (Aspect_Id) of Name_Id :=
433     (No_Aspect                           => No_Name,
434      Aspect_Abstract_State               => Name_Abstract_State,
435      Aspect_Address                      => Name_Address,
436      Aspect_Alignment                    => Name_Alignment,
437      Aspect_All_Calls_Remote             => Name_All_Calls_Remote,
438      Aspect_Annotate                     => Name_Annotate,
439      Aspect_Async_Readers                => Name_Async_Readers,
440      Aspect_Async_Writers                => Name_Async_Writers,
441      Aspect_Asynchronous                 => Name_Asynchronous,
442      Aspect_Atomic                       => Name_Atomic,
443      Aspect_Atomic_Components            => Name_Atomic_Components,
444      Aspect_Attach_Handler               => Name_Attach_Handler,
445      Aspect_Bit_Order                    => Name_Bit_Order,
446      Aspect_Component_Size               => Name_Component_Size,
447      Aspect_Constant_After_Elaboration   => Name_Constant_After_Elaboration,
448      Aspect_Constant_Indexing            => Name_Constant_Indexing,
449      Aspect_Contract_Cases               => Name_Contract_Cases,
450      Aspect_Convention                   => Name_Convention,
451      Aspect_CPU                          => Name_CPU,
452      Aspect_Default_Component_Value      => Name_Default_Component_Value,
453      Aspect_Default_Initial_Condition    => Name_Default_Initial_Condition,
454      Aspect_Default_Iterator             => Name_Default_Iterator,
455      Aspect_Default_Storage_Pool         => Name_Default_Storage_Pool,
456      Aspect_Default_Value                => Name_Default_Value,
457      Aspect_Depends                      => Name_Depends,
458      Aspect_Dimension                    => Name_Dimension,
459      Aspect_Dimension_System             => Name_Dimension_System,
460      Aspect_Disable_Controlled           => Name_Disable_Controlled,
461      Aspect_Discard_Names                => Name_Discard_Names,
462      Aspect_Dispatching_Domain           => Name_Dispatching_Domain,
463      Aspect_Dynamic_Predicate            => Name_Dynamic_Predicate,
464      Aspect_Effective_Reads              => Name_Effective_Reads,
465      Aspect_Effective_Writes             => Name_Effective_Writes,
466      Aspect_Elaborate_Body               => Name_Elaborate_Body,
467      Aspect_Export                       => Name_Export,
468      Aspect_Extensions_Visible           => Name_Extensions_Visible,
469      Aspect_External_Name                => Name_External_Name,
470      Aspect_External_Tag                 => Name_External_Tag,
471      Aspect_Favor_Top_Level              => Name_Favor_Top_Level,
472      Aspect_Ghost                        => Name_Ghost,
473      Aspect_Global                       => Name_Global,
474      Aspect_Implicit_Dereference         => Name_Implicit_Dereference,
475      Aspect_Import                       => Name_Import,
476      Aspect_Independent                  => Name_Independent,
477      Aspect_Independent_Components       => Name_Independent_Components,
478      Aspect_Inline                       => Name_Inline,
479      Aspect_Inline_Always                => Name_Inline_Always,
480      Aspect_Initial_Condition            => Name_Initial_Condition,
481      Aspect_Initializes                  => Name_Initializes,
482      Aspect_Input                        => Name_Input,
483      Aspect_Interrupt_Handler            => Name_Interrupt_Handler,
484      Aspect_Interrupt_Priority           => Name_Interrupt_Priority,
485      Aspect_Invariant                    => Name_Invariant,
486      Aspect_Iterator_Element             => Name_Iterator_Element,
487      Aspect_Iterable                     => Name_Iterable,
488      Aspect_Link_Name                    => Name_Link_Name,
489      Aspect_Linker_Section               => Name_Linker_Section,
490      Aspect_Lock_Free                    => Name_Lock_Free,
491      Aspect_Machine_Radix                => Name_Machine_Radix,
492      Aspect_Max_Entry_Queue_Depth        => Name_Max_Entry_Queue_Depth,
493      Aspect_Max_Entry_Queue_Length       => Name_Max_Entry_Queue_Length,
494      Aspect_Max_Queue_Length             => Name_Max_Queue_Length,
495      Aspect_No_Caching                   => Name_No_Caching,
496      Aspect_No_Elaboration_Code_All      => Name_No_Elaboration_Code_All,
497      Aspect_No_Inline                    => Name_No_Inline,
498      Aspect_No_Return                    => Name_No_Return,
499      Aspect_No_Tagged_Streams            => Name_No_Tagged_Streams,
500      Aspect_Object_Size                  => Name_Object_Size,
501      Aspect_Obsolescent                  => Name_Obsolescent,
502      Aspect_Output                       => Name_Output,
503      Aspect_Pack                         => Name_Pack,
504      Aspect_Part_Of                      => Name_Part_Of,
505      Aspect_Persistent_BSS               => Name_Persistent_BSS,
506      Aspect_Post                         => Name_Post,
507      Aspect_Postcondition                => Name_Postcondition,
508      Aspect_Pre                          => Name_Pre,
509      Aspect_Precondition                 => Name_Precondition,
510      Aspect_Predicate                    => Name_Predicate,
511      Aspect_Predicate_Failure            => Name_Predicate_Failure,
512      Aspect_Preelaborable_Initialization => Name_Preelaborable_Initialization,
513      Aspect_Preelaborate                 => Name_Preelaborate,
514      Aspect_Priority                     => Name_Priority,
515      Aspect_Pure                         => Name_Pure,
516      Aspect_Pure_Function                => Name_Pure_Function,
517      Aspect_Read                         => Name_Read,
518      Aspect_Refined_Depends              => Name_Refined_Depends,
519      Aspect_Refined_Global               => Name_Refined_Global,
520      Aspect_Refined_Post                 => Name_Refined_Post,
521      Aspect_Refined_State                => Name_Refined_State,
522      Aspect_Relative_Deadline            => Name_Relative_Deadline,
523      Aspect_Remote_Access_Type           => Name_Remote_Access_Type,
524      Aspect_Remote_Call_Interface        => Name_Remote_Call_Interface,
525      Aspect_Remote_Types                 => Name_Remote_Types,
526      Aspect_Scalar_Storage_Order         => Name_Scalar_Storage_Order,
527      Aspect_Secondary_Stack_Size         => Name_Secondary_Stack_Size,
528      Aspect_Shared                       => Name_Shared,
529      Aspect_Shared_Passive               => Name_Shared_Passive,
530      Aspect_Simple_Storage_Pool          => Name_Simple_Storage_Pool,
531      Aspect_Simple_Storage_Pool_Type     => Name_Simple_Storage_Pool_Type,
532      Aspect_Size                         => Name_Size,
533      Aspect_Small                        => Name_Small,
534      Aspect_SPARK_Mode                   => Name_SPARK_Mode,
535      Aspect_Static_Predicate             => Name_Static_Predicate,
536      Aspect_Storage_Pool                 => Name_Storage_Pool,
537      Aspect_Storage_Size                 => Name_Storage_Size,
538      Aspect_Stream_Size                  => Name_Stream_Size,
539      Aspect_Suppress                     => Name_Suppress,
540      Aspect_Suppress_Debug_Info          => Name_Suppress_Debug_Info,
541      Aspect_Suppress_Initialization      => Name_Suppress_Initialization,
542      Aspect_Thread_Local_Storage         => Name_Thread_Local_Storage,
543      Aspect_Synchronization              => Name_Synchronization,
544      Aspect_Test_Case                    => Name_Test_Case,
545      Aspect_Type_Invariant               => Name_Type_Invariant,
546      Aspect_Unchecked_Union              => Name_Unchecked_Union,
547      Aspect_Unimplemented                => Name_Unimplemented,
548      Aspect_Universal_Aliasing           => Name_Universal_Aliasing,
549      Aspect_Universal_Data               => Name_Universal_Data,
550      Aspect_Unmodified                   => Name_Unmodified,
551      Aspect_Unreferenced                 => Name_Unreferenced,
552      Aspect_Unreferenced_Objects         => Name_Unreferenced_Objects,
553      Aspect_Unsuppress                   => Name_Unsuppress,
554      Aspect_Value_Size                   => Name_Value_Size,
555      Aspect_Variable_Indexing            => Name_Variable_Indexing,
556      Aspect_Volatile                     => Name_Volatile,
557      Aspect_Volatile_Components          => Name_Volatile_Components,
558      Aspect_Volatile_Full_Access         => Name_Volatile_Full_Access,
559      Aspect_Volatile_Function            => Name_Volatile_Function,
560      Aspect_Warnings                     => Name_Warnings,
561      Aspect_Write                        => Name_Write);
562
563   function Get_Aspect_Id (Name : Name_Id) return Aspect_Id;
564   pragma Inline (Get_Aspect_Id);
565   --  Given a name Nam, returns the corresponding aspect id value. If the name
566   --  does not match any aspect, then No_Aspect is returned as the result.
567
568   function Get_Aspect_Id (Aspect : Node_Id) return Aspect_Id;
569   pragma Inline (Get_Aspect_Id);
570   --  Given an aspect specification, return the corresponding aspect_id value.
571   --  If the name does not match any aspect, return No_Aspect.
572
573   ------------------------------------
574   -- Delaying Evaluation of Aspects --
575   ------------------------------------
576
577   --  The RM requires that all language defined aspects taking an expression
578   --  delay evaluation of the expression till the freeze point of the entity
579   --  to which the aspect applies. This allows forward references, and is of
580   --  use for example in connection with preconditions and postconditions
581   --  where the requirement of making all references in contracts to local
582   --  functions be backwards references would be onerous.
583
584   --  For consistency, even attributes like Size are delayed, so we can do:
585
586   --    type A is range 1 .. 10
587   --      with Size => Not_Defined_Yet;
588   --    ..
589   --    Not_Defined_Yet : constant := 64;
590
591   --  Resulting in A having a size of 64, which gets set when A is frozen.
592   --  Furthermore, we can have a situation like
593
594   --    type A is range 1 .. 10
595   --      with Size => Not_Defined_Yet;
596   --    ..
597   --    type B is new A;
598   --    ..
599   --    Not_Defined_Yet : constant := 64;
600
601   --  where the Size of A is considered to have been previously specified at
602   --  the point of derivation, even though the actual value of the size is
603   --  not known yet, and in this example B inherits the size value of 64.
604
605   --  Our normal implementation model (prior to Ada 2012) was simply to copy
606   --  inheritable attributes at the point of derivation. Then any subsequent
607   --  representation items apply either to the parent type, not affecting the
608   --  derived type, or to the derived type, not affecting the parent type.
609
610   --  To deal with the delayed aspect case, we use two flags. The first is
611   --  set on the parent type if it has delayed representation aspects. This
612   --  flag Has_Delayed_Rep_Aspects indicates that if we derive from this type
613   --  we have to worry about making sure we inherit any delayed aspects. The
614   --  second flag is set on a derived type: May_Have_Inherited_Rep_Aspects
615   --  is set if the parent type has Has_Delayed_Rep_Aspects set.
616
617   --  When we freeze a derived type, if the May_Have_Inherited_Rep_Aspects
618   --  flag is set, then we call Freeze.Inherit_Delayed_Rep_Aspects when
619   --  the derived type is frozen, which deals with the necessary copying of
620   --  information from the parent type, which must be frozen at that point
621   --  (since freezing the derived type first freezes the parent type).
622
623   --  SPARK 2014 aspects do not follow the general delay mechanism as they
624   --  act as annotations and cannot modify the attributes of their related
625   --  constructs. To handle forward references in such aspects, the compiler
626   --  delays the analysis of their respective pragmas by collecting them in
627   --  N_Contract nodes. The pragmas are then analyzed at the end of the
628   --  declarative region containing the related construct. For details,
629   --  see routines Analyze_xxx_In_Decl_Part.
630
631   --  The following shows which aspects are delayed. There are three cases:
632
633   type Delay_Type is
634     (Always_Delay,
635      --  This aspect is not a representation aspect that can be inherited and
636      --  is always delayed, as required by the language definition.
637
638      Never_Delay,
639      --  There are two cases. There are language defined aspects like
640      --  Convention where the "expression" is simply an uninterpreted
641      --  identifier, and there is no issue of evaluating it and thus no
642      --  issue of delaying the evaluation. The second case is implementation
643      --  defined aspects where we have decided that we don't want to allow
644      --  delays (and for our own aspects we can do what we like).
645
646      Rep_Aspect);
647      --  These are the cases of representation aspects that are in general
648      --  delayed, and where there is a potential issue of derived types that
649      --  inherit delayed representation values.
650
651   --  Note: even if this table indicates that an aspect is delayed, we never
652   --  delay Boolean aspects that have a missing expression (taken as True),
653   --  or expressions for delayed rep items that consist of an integer literal
654   --  (most cases of Size etc. in practice), since in these cases we know we
655   --  can get the value of the expression without delay. Note that we still
656   --  need to delay Boolean aspects that are specifically set to True:
657
658   --     type R is array (0 .. 31) of Boolean
659   --       with Pack => True;
660   --     True : constant Boolean := False;
661
662   --  This is nonsense, but we need to make it work and result in R not
663   --  being packed, and if we have something like:
664
665   --     type R is array (0 .. 31) of Boolean
666   --       with Pack => True;
667   --     RR : R;
668   --     True : constant Boolean := False;
669
670   --  This is illegal because the visibility of True changes after the freeze
671   --  point, which is not allowed, and we need the delay mechanism to properly
672   --  diagnose this error.
673
674   Aspect_Delay : constant array (Aspect_Id) of Delay_Type :=
675     (No_Aspect                           => Always_Delay,
676      Aspect_Address                      => Always_Delay,
677      Aspect_All_Calls_Remote             => Always_Delay,
678      Aspect_Asynchronous                 => Always_Delay,
679      Aspect_Attach_Handler               => Always_Delay,
680      Aspect_Constant_Indexing            => Always_Delay,
681      Aspect_CPU                          => Always_Delay,
682      Aspect_Default_Iterator             => Always_Delay,
683      Aspect_Default_Storage_Pool         => Always_Delay,
684      Aspect_Default_Value                => Always_Delay,
685      Aspect_Default_Component_Value      => Always_Delay,
686      Aspect_Discard_Names                => Always_Delay,
687      Aspect_Dispatching_Domain           => Always_Delay,
688      Aspect_Dynamic_Predicate            => Always_Delay,
689      Aspect_Elaborate_Body               => Always_Delay,
690      Aspect_External_Name                => Always_Delay,
691      Aspect_External_Tag                 => Always_Delay,
692      Aspect_Favor_Top_Level              => Always_Delay,
693      Aspect_Implicit_Dereference         => Always_Delay,
694      Aspect_Independent                  => Always_Delay,
695      Aspect_Independent_Components       => Always_Delay,
696      Aspect_Inline                       => Always_Delay,
697      Aspect_Inline_Always                => Always_Delay,
698      Aspect_Input                        => Always_Delay,
699      Aspect_Interrupt_Handler            => Always_Delay,
700      Aspect_Interrupt_Priority           => Always_Delay,
701      Aspect_Invariant                    => Always_Delay,
702      Aspect_Iterable                     => Always_Delay,
703      Aspect_Iterator_Element             => Always_Delay,
704      Aspect_Link_Name                    => Always_Delay,
705      Aspect_Linker_Section               => Always_Delay,
706      Aspect_Lock_Free                    => Always_Delay,
707      Aspect_No_Inline                    => Always_Delay,
708      Aspect_No_Return                    => Always_Delay,
709      Aspect_Output                       => Always_Delay,
710      Aspect_Persistent_BSS               => Always_Delay,
711      Aspect_Post                         => Always_Delay,
712      Aspect_Postcondition                => Always_Delay,
713      Aspect_Pre                          => Always_Delay,
714      Aspect_Precondition                 => Always_Delay,
715      Aspect_Predicate                    => Always_Delay,
716      Aspect_Predicate_Failure            => Always_Delay,
717      Aspect_Preelaborable_Initialization => Always_Delay,
718      Aspect_Preelaborate                 => Always_Delay,
719      Aspect_Priority                     => Always_Delay,
720      Aspect_Pure                         => Always_Delay,
721      Aspect_Pure_Function                => Always_Delay,
722      Aspect_Read                         => Always_Delay,
723      Aspect_Relative_Deadline            => Always_Delay,
724      Aspect_Remote_Access_Type           => Always_Delay,
725      Aspect_Remote_Call_Interface        => Always_Delay,
726      Aspect_Remote_Types                 => Always_Delay,
727      Aspect_Secondary_Stack_Size         => Always_Delay,
728      Aspect_Shared                       => Always_Delay,
729      Aspect_Shared_Passive               => Always_Delay,
730      Aspect_Simple_Storage_Pool          => Always_Delay,
731      Aspect_Simple_Storage_Pool_Type     => Always_Delay,
732      Aspect_Static_Predicate             => Always_Delay,
733      Aspect_Storage_Pool                 => Always_Delay,
734      Aspect_Stream_Size                  => Always_Delay,
735      Aspect_Suppress                     => Always_Delay,
736      Aspect_Suppress_Debug_Info          => Always_Delay,
737      Aspect_Suppress_Initialization      => Always_Delay,
738      Aspect_Thread_Local_Storage         => Always_Delay,
739      Aspect_Type_Invariant               => Always_Delay,
740      Aspect_Unchecked_Union              => Always_Delay,
741      Aspect_Universal_Aliasing           => Always_Delay,
742      Aspect_Universal_Data               => Always_Delay,
743      Aspect_Unmodified                   => Always_Delay,
744      Aspect_Unreferenced                 => Always_Delay,
745      Aspect_Unreferenced_Objects         => Always_Delay,
746      Aspect_Unsuppress                   => Always_Delay,
747      Aspect_Variable_Indexing            => Always_Delay,
748      Aspect_Write                        => Always_Delay,
749
750      Aspect_Abstract_State               => Never_Delay,
751      Aspect_Annotate                     => Never_Delay,
752      Aspect_Async_Readers                => Never_Delay,
753      Aspect_Async_Writers                => Never_Delay,
754      Aspect_Constant_After_Elaboration   => Never_Delay,
755      Aspect_Contract_Cases               => Never_Delay,
756      Aspect_Convention                   => Never_Delay,
757      Aspect_Default_Initial_Condition    => Never_Delay,
758      Aspect_Depends                      => Never_Delay,
759      Aspect_Dimension                    => Never_Delay,
760      Aspect_Dimension_System             => Never_Delay,
761      Aspect_Disable_Controlled           => Never_Delay,
762      Aspect_Effective_Reads              => Never_Delay,
763      Aspect_Effective_Writes             => Never_Delay,
764      Aspect_Export                       => Never_Delay,
765      Aspect_Extensions_Visible           => Never_Delay,
766      Aspect_Ghost                        => Never_Delay,
767      Aspect_Global                       => Never_Delay,
768      Aspect_Import                       => Never_Delay,
769      Aspect_Initial_Condition            => Never_Delay,
770      Aspect_Initializes                  => Never_Delay,
771      Aspect_Max_Entry_Queue_Depth        => Never_Delay,
772      Aspect_Max_Entry_Queue_Length       => Never_Delay,
773      Aspect_Max_Queue_Length             => Never_Delay,
774      Aspect_No_Caching                   => Never_Delay,
775      Aspect_No_Elaboration_Code_All      => Never_Delay,
776      Aspect_No_Tagged_Streams            => Never_Delay,
777      Aspect_Obsolescent                  => Never_Delay,
778      Aspect_Part_Of                      => Never_Delay,
779      Aspect_Refined_Depends              => Never_Delay,
780      Aspect_Refined_Global               => Never_Delay,
781      Aspect_Refined_Post                 => Never_Delay,
782      Aspect_Refined_State                => Never_Delay,
783      Aspect_SPARK_Mode                   => Never_Delay,
784      Aspect_Synchronization              => Never_Delay,
785      Aspect_Test_Case                    => Never_Delay,
786      Aspect_Unimplemented                => Never_Delay,
787      Aspect_Volatile_Function            => Never_Delay,
788      Aspect_Warnings                     => Never_Delay,
789
790      Aspect_Alignment                    => Rep_Aspect,
791      Aspect_Atomic                       => Rep_Aspect,
792      Aspect_Atomic_Components            => Rep_Aspect,
793      Aspect_Bit_Order                    => Rep_Aspect,
794      Aspect_Component_Size               => Rep_Aspect,
795      Aspect_Machine_Radix                => Rep_Aspect,
796      Aspect_Object_Size                  => Rep_Aspect,
797      Aspect_Pack                         => Rep_Aspect,
798      Aspect_Scalar_Storage_Order         => Rep_Aspect,
799      Aspect_Size                         => Rep_Aspect,
800      Aspect_Small                        => Rep_Aspect,
801      Aspect_Storage_Size                 => Rep_Aspect,
802      Aspect_Value_Size                   => Rep_Aspect,
803      Aspect_Volatile                     => Rep_Aspect,
804      Aspect_Volatile_Components          => Rep_Aspect,
805      Aspect_Volatile_Full_Access         => Rep_Aspect);
806
807   ------------------------------------------------
808   -- Handling of Aspect Specifications on Stubs --
809   ------------------------------------------------
810
811   --  Aspects that appear on the following stub nodes
812
813   --    N_Package_Body_Stub
814   --    N_Protected_Body_Stub
815   --    N_Subprogram_Body_Stub
816   --    N_Task_Body_Stub
817
818   --  are treated as if they apply to the corresponding proper body. Their
819   --  analysis is postponed until the analysis of the proper body takes place
820   --  (see Analyze_Proper_Body). The delay is required because the analysis
821   --  may generate extra code which would be harder to relocate to the body.
822   --  If the proper body is present, the aspect specifications are relocated
823   --  to the corresponding body node:
824
825   --    N_Package_Body
826   --    N_Protected_Body
827   --    N_Subprogram_Body
828   --    N_Task_Body
829
830   --  The subsequent analysis takes care of the aspect-to-pragma conversions
831   --  and verification of pragma legality. In the case where the proper body
832   --  is not available, the aspect specifications are analyzed on the spot
833   --  (see Analyze_Proper_Body) to catch potential errors.
834
835   --  The following table lists all aspects that can apply to a subprogram
836   --  body [stub]. For instance, the following example is legal:
837
838   --    package P with SPARK_Mode ...;
839   --    package body P with SPARK_Mode is ...;
840
841   --  The table should be synchronized with Pragma_On_Body_Or_Stub_OK in unit
842   --  Sem_Prag.
843
844   Aspect_On_Body_Or_Stub_OK : constant array (Aspect_Id) of Boolean :=
845     (Aspect_Refined_Depends              => True,
846      Aspect_Refined_Global               => True,
847      Aspect_Refined_Post                 => True,
848      Aspect_SPARK_Mode                   => True,
849      Aspect_Warnings                     => True,
850      others                              => False);
851
852   -------------------------------------------------------------------
853   -- Handling of Aspects Specifications on Single Concurrent Types --
854   -------------------------------------------------------------------
855
856   --  Certain aspects that appear on the following nodes
857
858   --    N_Single_Protected_Declaration
859   --    N_Single_Task_Declaration
860
861   --  are treated as if they apply to the anonymous object produced by the
862   --  analysis of a single concurrent type. The following table lists all
863   --  aspects that should apply to the anonymous object. The table should
864   --  be synchronized with Pragma_On_Anonymous_Object_OK in unit Sem_Prag.
865
866   Aspect_On_Anonymous_Object_OK : constant array (Aspect_Id) of Boolean :=
867     (Aspect_Depends                      => True,
868      Aspect_Global                       => True,
869      Aspect_Part_Of                      => True,
870      others                              => False);
871
872   ---------------------------------------------------
873   -- Handling of Aspect Specifications in the Tree --
874   ---------------------------------------------------
875
876   --  Several kinds of declaration node permit aspect specifications in Ada
877   --  2012 mode. If there was room in all the corresponding declaration nodes,
878   --  we could just have a field Aspect_Specifications pointing to a list of
879   --  nodes for the aspects (N_Aspect_Specification nodes). But there isn't
880   --  room, so we adopt a different approach.
881
882   --  The following subprograms provide access to a specialized interface
883   --  implemented internally with a hash table in the body, that provides
884   --  access to aspect specifications.
885
886   function Aspect_Specifications (N : Node_Id) return List_Id;
887   --  Given a node N, returns the list of N_Aspect_Specification nodes that
888   --  are attached to this declaration node. If the node is in the class of
889   --  declaration nodes that permit aspect specifications, as defined by the
890   --  predicate above, and if their Has_Aspects flag is set to True, then this
891   --  will always be a non-empty list. If this flag is set to False, then
892   --  No_List is returned. Normally, the only nodes that have Has_Aspects set
893   --  True are the nodes for which Permits_Aspect_Specifications would return
894   --  True (i.e. the declaration nodes defined in the RM as permitting the
895   --  presence of Aspect_Specifications). However, it is possible for the
896   --  flag Has_Aspects to be set on other nodes as a result of Rewrite and
897   --  Replace calls, and this function may be used to retrieve the aspect
898   --  specifications for the original rewritten node in such cases.
899
900   function Aspects_On_Body_Or_Stub_OK (N : Node_Id) return Boolean;
901   --  N denotes a body [stub] with aspects. Determine whether all aspects of N
902   --  are allowed to appear on a body [stub].
903
904   procedure Exchange_Aspects (N1 : Node_Id; N2 : Node_Id);
905   --  Exchange the aspect specifications of two nodes. If either node lacks an
906   --  aspect specification list, the routine has no effect. It is assumed that
907   --  both nodes can support aspects.
908
909   function Find_Aspect (Id : Entity_Id; A : Aspect_Id) return Node_Id;
910   --  Find the aspect specification of aspect A associated with entity I.
911   --  Return Empty if Id does not have the requested aspect.
912
913   function Find_Value_Of_Aspect
914     (Id : Entity_Id;
915      A  : Aspect_Id) return Node_Id;
916   --  Find the value of aspect A associated with entity Id. Return Empty if
917   --  Id does not have the requested aspect.
918
919   function Has_Aspect (Id : Entity_Id; A : Aspect_Id) return Boolean;
920   --  Determine whether entity Id has aspect A
921
922   procedure Move_Aspects (From : Node_Id; To : Node_Id);
923   --  Relocate the aspect specifications of node From to node To. On entry it
924   --  is assumed that To does not have aspect specifications. If From has no
925   --  aspects, the routine has no effect.
926
927   procedure Move_Or_Merge_Aspects (From : Node_Id; To : Node_Id);
928   --  Relocate the aspect specifications of node From to node To. If To has
929   --  aspects, the aspects of From are appended to the aspects of To. If From
930   --  has no aspects, the routine has no effect. Special behavior:
931   --    * When node From denotes a subprogram body stub without a previous
932   --      declaration, the only aspects relocated to node To are those found
933   --      in table Aspect_On_Body_Or_Stub_OK.
934   --    * When node From denotes a single synchronized type declaration, the
935   --      only aspects relocated to node To are those found in table
936   --      Aspect_On_Anonymous_Object_OK.
937
938   function Permits_Aspect_Specifications (N : Node_Id) return Boolean;
939   --  Returns True if the node N is a declaration node that permits aspect
940   --  specifications in the grammar. It is possible for other nodes to have
941   --  aspect specifications as a result of Rewrite or Replace calls.
942
943   procedure Remove_Aspects (N : Node_Id);
944   --  Delete the aspect specifications associated with node N. If the node has
945   --  no aspects, the routine has no effect.
946
947   function Same_Aspect (A1 : Aspect_Id; A2 : Aspect_Id) return Boolean;
948   --  Returns True if A1 and A2 are (essentially) the same aspect. This is not
949   --  a simple equality test because e.g. Post and Postcondition are the same.
950   --  This is used for detecting duplicate aspects.
951
952   procedure Set_Aspect_Specifications (N : Node_Id; L : List_Id);
953   --  The node N must be in the class of declaration nodes that permit aspect
954   --  specifications and the Has_Aspects flag must be False on entry. L must
955   --  be a non-empty list of N_Aspect_Specification nodes. This procedure sets
956   --  the Has_Aspects flag to True, and makes an entry that can be retrieved
957   --  by a subsequent Aspect_Specifications call. It is an error to call this
958   --  procedure with a node that does not permit aspect specifications, or a
959   --  node that has its Has_Aspects flag set True on entry, or with L being an
960   --  empty list or No_List.
961
962   procedure Tree_Read;
963   --  Reads contents of Aspect_Specifications hash table from the tree file
964
965   procedure Tree_Write;
966   --  Writes contents of Aspect_Specifications hash table to the tree file
967
968end Aspects;
969