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) 2010-2015, 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 pre-analyzed
63--       at the end of the declaration list to which the subprogram belongs,
64--       and fully analyzed (possibly with expansion) during the semantic
65--       analysis of subprogram bodies.
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_Object_Size,                   -- GNAT
120      Aspect_Obsolescent,                   -- GNAT
121      Aspect_Output,
122      Aspect_Part_Of,                       -- GNAT
123      Aspect_Post,
124      Aspect_Postcondition,
125      Aspect_Pre,
126      Aspect_Precondition,
127      Aspect_Predicate,                     -- GNAT
128      Aspect_Predicate_Failure,
129      Aspect_Priority,
130      Aspect_Read,
131      Aspect_Refined_Depends,               -- GNAT
132      Aspect_Refined_Global,                -- GNAT
133      Aspect_Refined_Post,                  -- GNAT
134      Aspect_Refined_State,                 -- GNAT
135      Aspect_Relative_Deadline,
136      Aspect_Scalar_Storage_Order,          -- GNAT
137      Aspect_Simple_Storage_Pool,           -- GNAT
138      Aspect_Size,
139      Aspect_Small,
140      Aspect_SPARK_Mode,                    -- GNAT
141      Aspect_Static_Predicate,
142      Aspect_Storage_Pool,
143      Aspect_Storage_Size,
144      Aspect_Stream_Size,
145      Aspect_Suppress,
146      Aspect_Synchronization,
147      Aspect_Test_Case,                     -- GNAT
148      Aspect_Type_Invariant,
149      Aspect_Unimplemented,                 -- GNAT
150      Aspect_Unsuppress,
151      Aspect_Value_Size,                    -- GNAT
152      Aspect_Variable_Indexing,
153      Aspect_Volatile_Function,             -- GNAT
154      Aspect_Warnings,                      -- GNAT
155      Aspect_Write,
156
157      --  The following aspects correspond to library unit pragmas
158
159      Aspect_All_Calls_Remote,
160      Aspect_Elaborate_Body,
161      Aspect_No_Elaboration_Code_All,       -- GNAT
162      Aspect_Preelaborate,
163      Aspect_Pure,
164      Aspect_Remote_Call_Interface,
165      Aspect_Remote_Types,
166      Aspect_Shared_Passive,
167      Aspect_Universal_Data,                -- GNAT
168
169      --  Remaining aspects have a static boolean value that turns the aspect
170      --  on or off. They all correspond to pragmas, but are only converted to
171      --  the pragmas where the value is True. A value of False normally means
172      --  that the aspect is ignored, except in the case of derived types where
173      --  the aspect value is inherited from the parent, in which case, we do
174      --  not allow False if we inherit a True value from the parent.
175
176      Aspect_Asynchronous,
177      Aspect_Atomic,
178      Aspect_Atomic_Components,
179      Aspect_Disable_Controlled,            -- GNAT
180      Aspect_Discard_Names,
181      Aspect_Export,
182      Aspect_Favor_Top_Level,               -- GNAT
183      Aspect_Independent,
184      Aspect_Independent_Components,
185      Aspect_Import,
186      Aspect_Inline,
187      Aspect_Inline_Always,                 -- GNAT
188      Aspect_Interrupt_Handler,
189      Aspect_Lock_Free,                     -- GNAT
190      Aspect_No_Return,
191      Aspect_No_Tagged_Streams,             -- GNAT
192      Aspect_Pack,
193      Aspect_Persistent_BSS,                -- GNAT
194      Aspect_Preelaborable_Initialization,
195      Aspect_Pure_Function,                 -- GNAT
196      Aspect_Remote_Access_Type,            -- GNAT
197      Aspect_Shared,                        -- GNAT (equivalent to Atomic)
198      Aspect_Simple_Storage_Pool_Type,      -- GNAT
199      Aspect_Suppress_Debug_Info,           -- GNAT
200      Aspect_Suppress_Initialization,       -- GNAT
201      Aspect_Thread_Local_Storage,          -- GNAT
202      Aspect_Unchecked_Union,
203      Aspect_Universal_Aliasing,            -- GNAT
204      Aspect_Unmodified,                    -- GNAT
205      Aspect_Unreferenced,                  -- GNAT
206      Aspect_Unreferenced_Objects,          -- GNAT
207      Aspect_Volatile,
208      Aspect_Volatile_Components,
209      Aspect_Volatile_Full_Access);         -- GNAT
210
211   subtype Aspect_Id_Exclude_No_Aspect is
212     Aspect_Id range Aspect_Id'Succ (No_Aspect) .. Aspect_Id'Last;
213   --  Aspect_Id's excluding No_Aspect
214
215   --  The following array indicates aspects that accept 'Class
216
217   Class_Aspect_OK : constant array (Aspect_Id) of Boolean :=
218     (Aspect_Input          => True,
219      Aspect_Invariant      => True,
220      Aspect_Output         => True,
221      Aspect_Pre            => True,
222      Aspect_Predicate      => True,
223      Aspect_Post           => True,
224      Aspect_Read           => True,
225      Aspect_Write          => True,
226      Aspect_Type_Invariant => True,
227      others                => False);
228
229   --  The following array identifies all implementation defined aspects
230
231   Implementation_Defined_Aspect : constant array (Aspect_Id) of Boolean :=
232     (Aspect_Abstract_State             => True,
233      Aspect_Annotate                   => True,
234      Aspect_Async_Readers              => True,
235      Aspect_Async_Writers              => True,
236      Aspect_Constant_After_Elaboration => True,
237      Aspect_Contract_Cases             => True,
238      Aspect_Depends                    => True,
239      Aspect_Dimension                  => True,
240      Aspect_Dimension_System           => True,
241      Aspect_Effective_Reads            => True,
242      Aspect_Effective_Writes           => True,
243      Aspect_Extensions_Visible         => True,
244      Aspect_Favor_Top_Level            => True,
245      Aspect_Ghost                      => True,
246      Aspect_Global                     => True,
247      Aspect_Inline_Always              => True,
248      Aspect_Invariant                  => True,
249      Aspect_Lock_Free                  => True,
250      Aspect_Object_Size                => True,
251      Aspect_Persistent_BSS             => True,
252      Aspect_Predicate                  => True,
253      Aspect_Pure_Function              => True,
254      Aspect_Remote_Access_Type         => True,
255      Aspect_Scalar_Storage_Order       => True,
256      Aspect_Shared                     => True,
257      Aspect_Simple_Storage_Pool        => True,
258      Aspect_Simple_Storage_Pool_Type   => True,
259      Aspect_Suppress_Debug_Info        => True,
260      Aspect_Suppress_Initialization    => True,
261      Aspect_Thread_Local_Storage       => True,
262      Aspect_Test_Case                  => True,
263      Aspect_Universal_Aliasing         => True,
264      Aspect_Universal_Data             => True,
265      Aspect_Unmodified                 => True,
266      Aspect_Unreferenced               => True,
267      Aspect_Unreferenced_Objects       => True,
268      Aspect_Value_Size                 => True,
269      Aspect_Volatile_Function          => True,
270      Aspect_Warnings                   => True,
271      others                            => False);
272
273   --  The following array indicates aspects for which multiple occurrences of
274   --  the same aspect attached to the same declaration are allowed.
275
276   No_Duplicates_Allowed : constant array (Aspect_Id) of Boolean :=
277     (Aspect_Annotate  => False,
278      Aspect_Test_Case => False,
279      others           => True);
280
281   --  The following subtype defines aspects corresponding to library unit
282   --  pragmas, these can only validly appear as aspects for library units,
283   --  and result in a corresponding pragma being inserted immediately after
284   --  the occurrence of the aspect.
285
286   subtype Library_Unit_Aspects is
287     Aspect_Id range Aspect_All_Calls_Remote .. Aspect_Universal_Data;
288
289   --  The following subtype defines aspects accepting an optional static
290   --  boolean parameter indicating if the aspect should be active or
291   --  cancelling. If the parameter is missing the effective value is True,
292   --  enabling the aspect. If the parameter is present it must be a static
293   --  expression of type Standard.Boolean. If the value is True, then the
294   --  aspect is enabled. If it is False, the aspect is disabled.
295
296   subtype Boolean_Aspects is
297     Aspect_Id range Aspect_Asynchronous .. Aspect_Id'Last;
298
299   subtype Pre_Post_Aspects is
300     Aspect_Id range Aspect_Post .. Aspect_Precondition;
301
302   --  The following type is used for indicating allowed expression forms
303
304   type Aspect_Expression is
305     (Expression,             -- Required expression
306      Name,                   -- Required name
307      Optional_Expression,    -- Optional boolean expression
308      Optional_Name);         -- Optional name
309
310   --  The following array indicates what argument type is required
311
312   Aspect_Argument : constant array (Aspect_Id) of Aspect_Expression :=
313     (No_Aspect                         => Optional_Expression,
314      Aspect_Abstract_State             => Expression,
315      Aspect_Address                    => Expression,
316      Aspect_Alignment                  => Expression,
317      Aspect_Annotate                   => Expression,
318      Aspect_Async_Readers              => Optional_Expression,
319      Aspect_Async_Writers              => Optional_Expression,
320      Aspect_Attach_Handler             => Expression,
321      Aspect_Bit_Order                  => Expression,
322      Aspect_Component_Size             => Expression,
323      Aspect_Constant_After_Elaboration => Optional_Expression,
324      Aspect_Constant_Indexing          => Name,
325      Aspect_Contract_Cases             => Expression,
326      Aspect_Convention                 => Name,
327      Aspect_CPU                        => Expression,
328      Aspect_Default_Component_Value    => Expression,
329      Aspect_Default_Initial_Condition  => Optional_Expression,
330      Aspect_Default_Iterator           => Name,
331      Aspect_Default_Storage_Pool       => Expression,
332      Aspect_Default_Value              => Expression,
333      Aspect_Depends                    => Expression,
334      Aspect_Dimension                  => Expression,
335      Aspect_Dimension_System           => Expression,
336      Aspect_Dispatching_Domain         => Expression,
337      Aspect_Dynamic_Predicate          => Expression,
338      Aspect_Effective_Reads            => Optional_Expression,
339      Aspect_Effective_Writes           => Optional_Expression,
340      Aspect_Extensions_Visible         => Optional_Expression,
341      Aspect_External_Name              => Expression,
342      Aspect_External_Tag               => Expression,
343      Aspect_Ghost                      => Optional_Expression,
344      Aspect_Global                     => Expression,
345      Aspect_Implicit_Dereference       => Name,
346      Aspect_Initial_Condition          => Expression,
347      Aspect_Initializes                => Expression,
348      Aspect_Input                      => Name,
349      Aspect_Interrupt_Priority         => Expression,
350      Aspect_Invariant                  => Expression,
351      Aspect_Iterable                   => Expression,
352      Aspect_Iterator_Element           => Name,
353      Aspect_Link_Name                  => Expression,
354      Aspect_Linker_Section             => Expression,
355      Aspect_Machine_Radix              => Expression,
356      Aspect_Object_Size                => Expression,
357      Aspect_Obsolescent                => Optional_Expression,
358      Aspect_Output                     => Name,
359      Aspect_Part_Of                    => Expression,
360      Aspect_Post                       => Expression,
361      Aspect_Postcondition              => Expression,
362      Aspect_Pre                        => Expression,
363      Aspect_Precondition               => Expression,
364      Aspect_Predicate                  => Expression,
365      Aspect_Predicate_Failure          => Expression,
366      Aspect_Priority                   => Expression,
367      Aspect_Read                       => Name,
368      Aspect_Refined_Depends            => Expression,
369      Aspect_Refined_Global             => Expression,
370      Aspect_Refined_Post               => Expression,
371      Aspect_Refined_State              => Expression,
372      Aspect_Relative_Deadline          => Expression,
373      Aspect_Scalar_Storage_Order       => Expression,
374      Aspect_Simple_Storage_Pool        => Name,
375      Aspect_Size                       => Expression,
376      Aspect_Small                      => Expression,
377      Aspect_SPARK_Mode                 => Optional_Name,
378      Aspect_Static_Predicate           => Expression,
379      Aspect_Storage_Pool               => Name,
380      Aspect_Storage_Size               => Expression,
381      Aspect_Stream_Size                => Expression,
382      Aspect_Suppress                   => Name,
383      Aspect_Synchronization            => Name,
384      Aspect_Test_Case                  => Expression,
385      Aspect_Type_Invariant             => Expression,
386      Aspect_Unimplemented              => Optional_Expression,
387      Aspect_Unsuppress                 => Name,
388      Aspect_Value_Size                 => Expression,
389      Aspect_Variable_Indexing          => Name,
390      Aspect_Volatile_Function          => Optional_Expression,
391      Aspect_Warnings                   => Name,
392      Aspect_Write                      => Name,
393
394      Boolean_Aspects                   => Optional_Expression,
395      Library_Unit_Aspects              => Optional_Expression);
396
397   -----------------------------------------
398   -- Table Linking Names and Aspect_Id's --
399   -----------------------------------------
400
401   --  Table linking aspect names and id's
402
403   Aspect_Names : constant array (Aspect_Id) of Name_Id :=
404     (No_Aspect                           => No_Name,
405      Aspect_Abstract_State               => Name_Abstract_State,
406      Aspect_Address                      => Name_Address,
407      Aspect_Alignment                    => Name_Alignment,
408      Aspect_All_Calls_Remote             => Name_All_Calls_Remote,
409      Aspect_Annotate                     => Name_Annotate,
410      Aspect_Async_Readers                => Name_Async_Readers,
411      Aspect_Async_Writers                => Name_Async_Writers,
412      Aspect_Asynchronous                 => Name_Asynchronous,
413      Aspect_Atomic                       => Name_Atomic,
414      Aspect_Atomic_Components            => Name_Atomic_Components,
415      Aspect_Attach_Handler               => Name_Attach_Handler,
416      Aspect_Bit_Order                    => Name_Bit_Order,
417      Aspect_Component_Size               => Name_Component_Size,
418      Aspect_Constant_After_Elaboration   => Name_Constant_After_Elaboration,
419      Aspect_Constant_Indexing            => Name_Constant_Indexing,
420      Aspect_Contract_Cases               => Name_Contract_Cases,
421      Aspect_Convention                   => Name_Convention,
422      Aspect_CPU                          => Name_CPU,
423      Aspect_Default_Component_Value      => Name_Default_Component_Value,
424      Aspect_Default_Initial_Condition    => Name_Default_Initial_Condition,
425      Aspect_Default_Iterator             => Name_Default_Iterator,
426      Aspect_Default_Storage_Pool         => Name_Default_Storage_Pool,
427      Aspect_Default_Value                => Name_Default_Value,
428      Aspect_Depends                      => Name_Depends,
429      Aspect_Dimension                    => Name_Dimension,
430      Aspect_Dimension_System             => Name_Dimension_System,
431      Aspect_Disable_Controlled           => Name_Disable_Controlled,
432      Aspect_Discard_Names                => Name_Discard_Names,
433      Aspect_Dispatching_Domain           => Name_Dispatching_Domain,
434      Aspect_Dynamic_Predicate            => Name_Dynamic_Predicate,
435      Aspect_Effective_Reads              => Name_Effective_Reads,
436      Aspect_Effective_Writes             => Name_Effective_Writes,
437      Aspect_Elaborate_Body               => Name_Elaborate_Body,
438      Aspect_Export                       => Name_Export,
439      Aspect_Extensions_Visible           => Name_Extensions_Visible,
440      Aspect_External_Name                => Name_External_Name,
441      Aspect_External_Tag                 => Name_External_Tag,
442      Aspect_Favor_Top_Level              => Name_Favor_Top_Level,
443      Aspect_Ghost                        => Name_Ghost,
444      Aspect_Global                       => Name_Global,
445      Aspect_Implicit_Dereference         => Name_Implicit_Dereference,
446      Aspect_Import                       => Name_Import,
447      Aspect_Independent                  => Name_Independent,
448      Aspect_Independent_Components       => Name_Independent_Components,
449      Aspect_Inline                       => Name_Inline,
450      Aspect_Inline_Always                => Name_Inline_Always,
451      Aspect_Initial_Condition            => Name_Initial_Condition,
452      Aspect_Initializes                  => Name_Initializes,
453      Aspect_Input                        => Name_Input,
454      Aspect_Interrupt_Handler            => Name_Interrupt_Handler,
455      Aspect_Interrupt_Priority           => Name_Interrupt_Priority,
456      Aspect_Invariant                    => Name_Invariant,
457      Aspect_Iterator_Element             => Name_Iterator_Element,
458      Aspect_Iterable                     => Name_Iterable,
459      Aspect_Link_Name                    => Name_Link_Name,
460      Aspect_Linker_Section               => Name_Linker_Section,
461      Aspect_Lock_Free                    => Name_Lock_Free,
462      Aspect_Machine_Radix                => Name_Machine_Radix,
463      Aspect_No_Elaboration_Code_All      => Name_No_Elaboration_Code_All,
464      Aspect_No_Return                    => Name_No_Return,
465      Aspect_No_Tagged_Streams            => Name_No_Tagged_Streams,
466      Aspect_Object_Size                  => Name_Object_Size,
467      Aspect_Obsolescent                  => Name_Obsolescent,
468      Aspect_Output                       => Name_Output,
469      Aspect_Pack                         => Name_Pack,
470      Aspect_Part_Of                      => Name_Part_Of,
471      Aspect_Persistent_BSS               => Name_Persistent_BSS,
472      Aspect_Post                         => Name_Post,
473      Aspect_Postcondition                => Name_Postcondition,
474      Aspect_Pre                          => Name_Pre,
475      Aspect_Precondition                 => Name_Precondition,
476      Aspect_Predicate                    => Name_Predicate,
477      Aspect_Predicate_Failure            => Name_Predicate_Failure,
478      Aspect_Preelaborable_Initialization => Name_Preelaborable_Initialization,
479      Aspect_Preelaborate                 => Name_Preelaborate,
480      Aspect_Priority                     => Name_Priority,
481      Aspect_Pure                         => Name_Pure,
482      Aspect_Pure_Function                => Name_Pure_Function,
483      Aspect_Read                         => Name_Read,
484      Aspect_Refined_Depends              => Name_Refined_Depends,
485      Aspect_Refined_Global               => Name_Refined_Global,
486      Aspect_Refined_Post                 => Name_Refined_Post,
487      Aspect_Refined_State                => Name_Refined_State,
488      Aspect_Relative_Deadline            => Name_Relative_Deadline,
489      Aspect_Remote_Access_Type           => Name_Remote_Access_Type,
490      Aspect_Remote_Call_Interface        => Name_Remote_Call_Interface,
491      Aspect_Remote_Types                 => Name_Remote_Types,
492      Aspect_Scalar_Storage_Order         => Name_Scalar_Storage_Order,
493      Aspect_Shared                       => Name_Shared,
494      Aspect_Shared_Passive               => Name_Shared_Passive,
495      Aspect_Simple_Storage_Pool          => Name_Simple_Storage_Pool,
496      Aspect_Simple_Storage_Pool_Type     => Name_Simple_Storage_Pool_Type,
497      Aspect_Size                         => Name_Size,
498      Aspect_Small                        => Name_Small,
499      Aspect_SPARK_Mode                   => Name_SPARK_Mode,
500      Aspect_Static_Predicate             => Name_Static_Predicate,
501      Aspect_Storage_Pool                 => Name_Storage_Pool,
502      Aspect_Storage_Size                 => Name_Storage_Size,
503      Aspect_Stream_Size                  => Name_Stream_Size,
504      Aspect_Suppress                     => Name_Suppress,
505      Aspect_Suppress_Debug_Info          => Name_Suppress_Debug_Info,
506      Aspect_Suppress_Initialization      => Name_Suppress_Initialization,
507      Aspect_Thread_Local_Storage         => Name_Thread_Local_Storage,
508      Aspect_Synchronization              => Name_Synchronization,
509      Aspect_Test_Case                    => Name_Test_Case,
510      Aspect_Type_Invariant               => Name_Type_Invariant,
511      Aspect_Unchecked_Union              => Name_Unchecked_Union,
512      Aspect_Unimplemented                => Name_Unimplemented,
513      Aspect_Universal_Aliasing           => Name_Universal_Aliasing,
514      Aspect_Universal_Data               => Name_Universal_Data,
515      Aspect_Unmodified                   => Name_Unmodified,
516      Aspect_Unreferenced                 => Name_Unreferenced,
517      Aspect_Unreferenced_Objects         => Name_Unreferenced_Objects,
518      Aspect_Unsuppress                   => Name_Unsuppress,
519      Aspect_Value_Size                   => Name_Value_Size,
520      Aspect_Variable_Indexing            => Name_Variable_Indexing,
521      Aspect_Volatile                     => Name_Volatile,
522      Aspect_Volatile_Components          => Name_Volatile_Components,
523      Aspect_Volatile_Full_Access         => Name_Volatile_Full_Access,
524      Aspect_Volatile_Function            => Name_Volatile_Function,
525      Aspect_Warnings                     => Name_Warnings,
526      Aspect_Write                        => Name_Write);
527
528   function Get_Aspect_Id (Name : Name_Id) return Aspect_Id;
529   pragma Inline (Get_Aspect_Id);
530   --  Given a name Nam, returns the corresponding aspect id value. If the name
531   --  does not match any aspect, then No_Aspect is returned as the result.
532
533   function Get_Aspect_Id (Aspect : Node_Id) return Aspect_Id;
534   pragma Inline (Get_Aspect_Id);
535   --  Given an aspect specification, return the corresponding aspect_id value.
536   --  If the name does not match any aspect, return No_Aspect.
537
538   ------------------------------------
539   -- Delaying Evaluation of Aspects --
540   ------------------------------------
541
542   --  The RM requires that all language defined aspects taking an expression
543   --  delay evaluation of the expression till the freeze point of the entity
544   --  to which the aspect applies. This allows forward references, and is of
545   --  use for example in connection with preconditions and postconditions
546   --  where the requirement of making all references in contracts to local
547   --  functions be backwards references would be onerous.
548
549   --  For consistency, even attributes like Size are delayed, so we can do:
550
551   --    type A is range 1 .. 10
552   --      with Size => Not_Defined_Yet;
553   --    ..
554   --    Not_Defined_Yet : constant := 64;
555
556   --  Resulting in A having a size of 64, which gets set when A is frozen.
557   --  Furthermore, we can have a situation like
558
559   --    type A is range 1 .. 10
560   --      with Size => Not_Defined_Yet;
561   --    ..
562   --    type B is new A;
563   --    ..
564   --    Not_Defined_Yet : constant := 64;
565
566   --  where the Size of A is considered to have been previously specified at
567   --  the point of derivation, even though the actual value of the size is
568   --  not known yet, and in this example B inherits the size value of 64.
569
570   --  Our normal implementation model (prior to Ada 2012) was simply to copy
571   --  inheritable attributes at the point of derivation. Then any subsequent
572   --  representation items apply either to the parent type, not affecting the
573   --  derived type, or to the derived type, not affecting the parent type.
574
575   --  To deal with the delayed aspect case, we use two flags. The first is
576   --  set on the parent type if it has delayed representation aspects. This
577   --  flag Has_Delayed_Rep_Aspects indicates that if we derive from this type
578   --  we have to worry about making sure we inherit any delayed aspects. The
579   --  second flag is set on a derived type: May_Have_Inherited_Rep_Aspects
580   --  is set if the parent type has Has_Delayed_Rep_Aspects set.
581
582   --  When we freeze a derived type, if the May_Have_Inherited_Rep_Aspects
583   --  flag is set, then we call Freeze.Inherit_Delayed_Rep_Aspects when
584   --  the derived type is frozen, which deals with the necessary copying of
585   --  information from the parent type, which must be frozen at that point
586   --  (since freezing the derived type first freezes the parent type).
587
588   --  SPARK 2014 aspects do not follow the general delay mechanism as they
589   --  act as annotations and cannot modify the attributes of their related
590   --  constructs. To handle forward references in such aspects, the compiler
591   --  delays the analysis of their respective pragmas by collecting them in
592   --  N_Contract nodes. The pragmas are then analyzed at the end of the
593   --  declarative region containing the related construct. For details,
594   --  see routines Analyze_xxx_In_Decl_Part.
595
596   --  The following shows which aspects are delayed. There are three cases:
597
598   type Delay_Type is
599     (Always_Delay,
600      --  This aspect is not a representation aspect that can be inherited and
601      --  is always delayed, as required by the language definition.
602
603      Never_Delay,
604      --  There are two cases. There are language defined aspects like
605      --  Convention where the "expression" is simply an uninterpreted
606      --  identifier, and there is no issue of evaluating it and thus no
607      --  issue of delaying the evaluation. The second case is implementation
608      --  defined aspects where we have decided that we don't want to allow
609      --  delays (and for our own aspects we can do what we like).
610
611      Rep_Aspect);
612      --  These are the cases of representation aspects that are in general
613      --  delayed, and where there is a potential issue of derived types that
614      --  inherit delayed representation values.
615
616   --  Note: even if this table indicates that an aspect is delayed, we never
617   --  delay Boolean aspects that have a missing expression (taken as True),
618   --  or expressions for delayed rep items that consist of an integer literal
619   --  (most cases of Size etc. in practice), since in these cases we know we
620   --  can get the value of the expression without delay. Note that we still
621   --  need to delay Boolean aspects that are specifically set to True:
622
623   --     type R is array (0 .. 31) of Boolean
624   --       with Pack => True;
625   --     True : constant Boolean := False;
626
627   --  This is nonsense, but we need to make it work and result in R not
628   --  being packed, and if we have something like:
629
630   --     type R is array (0 .. 31) of Boolean
631   --       with Pack => True;
632   --     RR : R;
633   --     True : constant Boolean := False;
634
635   --  This is illegal because the visibility of True changes after the freeze
636   --  point, which is not allowed, and we need the delay mechanism to properly
637   --  diagnose this error.
638
639   Aspect_Delay : constant array (Aspect_Id) of Delay_Type :=
640     (No_Aspect                           => Always_Delay,
641      Aspect_Address                      => Always_Delay,
642      Aspect_All_Calls_Remote             => Always_Delay,
643      Aspect_Asynchronous                 => Always_Delay,
644      Aspect_Attach_Handler               => Always_Delay,
645      Aspect_Constant_Indexing            => Always_Delay,
646      Aspect_CPU                          => Always_Delay,
647      Aspect_Default_Iterator             => Always_Delay,
648      Aspect_Default_Storage_Pool         => Always_Delay,
649      Aspect_Default_Value                => Always_Delay,
650      Aspect_Default_Component_Value      => Always_Delay,
651      Aspect_Discard_Names                => Always_Delay,
652      Aspect_Dispatching_Domain           => Always_Delay,
653      Aspect_Dynamic_Predicate            => Always_Delay,
654      Aspect_Elaborate_Body               => Always_Delay,
655      Aspect_Export                       => Always_Delay,
656      Aspect_External_Name                => Always_Delay,
657      Aspect_External_Tag                 => Always_Delay,
658      Aspect_Favor_Top_Level              => Always_Delay,
659      Aspect_Implicit_Dereference         => Always_Delay,
660      Aspect_Import                       => Always_Delay,
661      Aspect_Independent                  => Always_Delay,
662      Aspect_Independent_Components       => Always_Delay,
663      Aspect_Inline                       => Always_Delay,
664      Aspect_Inline_Always                => Always_Delay,
665      Aspect_Input                        => Always_Delay,
666      Aspect_Interrupt_Handler            => Always_Delay,
667      Aspect_Interrupt_Priority           => Always_Delay,
668      Aspect_Invariant                    => Always_Delay,
669      Aspect_Iterable                     => Always_Delay,
670      Aspect_Iterator_Element             => Always_Delay,
671      Aspect_Link_Name                    => Always_Delay,
672      Aspect_Linker_Section               => Always_Delay,
673      Aspect_Lock_Free                    => Always_Delay,
674      Aspect_No_Return                    => Always_Delay,
675      Aspect_Output                       => Always_Delay,
676      Aspect_Persistent_BSS               => Always_Delay,
677      Aspect_Post                         => Always_Delay,
678      Aspect_Postcondition                => Always_Delay,
679      Aspect_Pre                          => Always_Delay,
680      Aspect_Precondition                 => Always_Delay,
681      Aspect_Predicate                    => Always_Delay,
682      Aspect_Predicate_Failure            => Always_Delay,
683      Aspect_Preelaborable_Initialization => Always_Delay,
684      Aspect_Preelaborate                 => Always_Delay,
685      Aspect_Priority                     => Always_Delay,
686      Aspect_Pure                         => Always_Delay,
687      Aspect_Pure_Function                => Always_Delay,
688      Aspect_Read                         => Always_Delay,
689      Aspect_Relative_Deadline            => Always_Delay,
690      Aspect_Remote_Access_Type           => Always_Delay,
691      Aspect_Remote_Call_Interface        => Always_Delay,
692      Aspect_Remote_Types                 => Always_Delay,
693      Aspect_Shared                       => Always_Delay,
694      Aspect_Shared_Passive               => Always_Delay,
695      Aspect_Simple_Storage_Pool          => Always_Delay,
696      Aspect_Simple_Storage_Pool_Type     => Always_Delay,
697      Aspect_Static_Predicate             => Always_Delay,
698      Aspect_Storage_Pool                 => Always_Delay,
699      Aspect_Stream_Size                  => Always_Delay,
700      Aspect_Suppress                     => Always_Delay,
701      Aspect_Suppress_Debug_Info          => Always_Delay,
702      Aspect_Suppress_Initialization      => Always_Delay,
703      Aspect_Thread_Local_Storage         => Always_Delay,
704      Aspect_Type_Invariant               => Always_Delay,
705      Aspect_Unchecked_Union              => Always_Delay,
706      Aspect_Universal_Aliasing           => Always_Delay,
707      Aspect_Universal_Data               => Always_Delay,
708      Aspect_Unmodified                   => Always_Delay,
709      Aspect_Unreferenced                 => Always_Delay,
710      Aspect_Unreferenced_Objects         => Always_Delay,
711      Aspect_Unsuppress                   => Always_Delay,
712      Aspect_Variable_Indexing            => Always_Delay,
713      Aspect_Write                        => Always_Delay,
714
715      Aspect_Abstract_State               => Never_Delay,
716      Aspect_Annotate                     => Never_Delay,
717      Aspect_Async_Readers                => Never_Delay,
718      Aspect_Async_Writers                => Never_Delay,
719      Aspect_Constant_After_Elaboration   => Never_Delay,
720      Aspect_Contract_Cases               => Never_Delay,
721      Aspect_Convention                   => Never_Delay,
722      Aspect_Default_Initial_Condition    => Never_Delay,
723      Aspect_Depends                      => Never_Delay,
724      Aspect_Dimension                    => Never_Delay,
725      Aspect_Dimension_System             => Never_Delay,
726      Aspect_Disable_Controlled           => Never_Delay,
727      Aspect_Effective_Reads              => Never_Delay,
728      Aspect_Effective_Writes             => Never_Delay,
729      Aspect_Extensions_Visible           => Never_Delay,
730      Aspect_Ghost                        => Never_Delay,
731      Aspect_Global                       => Never_Delay,
732      Aspect_Initial_Condition            => Never_Delay,
733      Aspect_Initializes                  => Never_Delay,
734      Aspect_No_Elaboration_Code_All      => Never_Delay,
735      Aspect_No_Tagged_Streams            => Never_Delay,
736      Aspect_Obsolescent                  => Never_Delay,
737      Aspect_Part_Of                      => Never_Delay,
738      Aspect_Refined_Depends              => Never_Delay,
739      Aspect_Refined_Global               => Never_Delay,
740      Aspect_Refined_Post                 => Never_Delay,
741      Aspect_Refined_State                => Never_Delay,
742      Aspect_SPARK_Mode                   => Never_Delay,
743      Aspect_Synchronization              => Never_Delay,
744      Aspect_Test_Case                    => Never_Delay,
745      Aspect_Unimplemented                => Never_Delay,
746      Aspect_Volatile_Function            => Never_Delay,
747      Aspect_Warnings                     => Never_Delay,
748
749      Aspect_Alignment                    => Rep_Aspect,
750      Aspect_Atomic                       => Rep_Aspect,
751      Aspect_Atomic_Components            => Rep_Aspect,
752      Aspect_Bit_Order                    => Rep_Aspect,
753      Aspect_Component_Size               => Rep_Aspect,
754      Aspect_Machine_Radix                => Rep_Aspect,
755      Aspect_Object_Size                  => Rep_Aspect,
756      Aspect_Pack                         => Rep_Aspect,
757      Aspect_Scalar_Storage_Order         => Rep_Aspect,
758      Aspect_Size                         => Rep_Aspect,
759      Aspect_Small                        => Rep_Aspect,
760      Aspect_Storage_Size                 => Rep_Aspect,
761      Aspect_Value_Size                   => Rep_Aspect,
762      Aspect_Volatile                     => Rep_Aspect,
763      Aspect_Volatile_Components          => Rep_Aspect,
764      Aspect_Volatile_Full_Access         => Rep_Aspect);
765
766   ------------------------------------------------
767   -- Handling of Aspect Specifications on Stubs --
768   ------------------------------------------------
769
770   --  Aspects that appear on the following stub nodes
771
772   --    N_Package_Body_Stub
773   --    N_Protected_Body_Stub
774   --    N_Subprogram_Body_Stub
775   --    N_Task_Body_Stub
776
777   --  are treated as if they apply to the corresponding proper body. Their
778   --  analysis is postponed until the analysis of the proper body takes place
779   --  (see Analyze_Proper_Body). The delay is required because the analysis
780   --  may generate extra code which would be harder to relocate to the body.
781   --  If the proper body is present, the aspect specifications are relocated
782   --  to the corresponding body node:
783
784   --    N_Package_Body
785   --    N_Protected_Body
786   --    N_Subprogram_Body
787   --    N_Task_Body
788
789   --  The subsequent analysis takes care of the aspect-to-pragma conversions
790   --  and verification of pragma legality. In the case where the proper body
791   --  is not available, the aspect specifications are analyzed on the spot
792   --  (see Analyze_Proper_Body) to catch potential errors.
793
794   --  The following table lists all aspects that can apply to a subprogram
795   --  body [stub]. For instance, the following example is legal:
796
797   --    package P with SPARK_Mode ...;
798   --    package body P with SPARK_Mode is ...;
799
800   --  The table should be synchronized with Pragma_On_Body_Or_Stub_OK in unit
801   --  Sem_Prag.
802
803   Aspect_On_Body_Or_Stub_OK : constant array (Aspect_Id) of Boolean :=
804     (Aspect_Refined_Depends              => True,
805      Aspect_Refined_Global               => True,
806      Aspect_Refined_Post                 => True,
807      Aspect_SPARK_Mode                   => True,
808      Aspect_Warnings                     => True,
809      others                              => False);
810
811   -------------------------------------------------------------------
812   -- Handling of Aspects Specifications on Single Concurrent Types --
813   -------------------------------------------------------------------
814
815   --  Certain aspects that appear on the following nodes
816
817   --    N_Single_Protected_Declaration
818   --    N_Single_Task_Declaration
819
820   --  are treated as if they apply to the anonymous object produced by the
821   --  analysis of a single concurrent type. The following table lists all
822   --  aspects that should apply to the anonymous object. The table should
823   --  be synchronized with Pragma_On_Anonymous_Object_OK in unit Sem_Prag.
824
825   Aspect_On_Anonymous_Object_OK : constant array (Aspect_Id) of Boolean :=
826     (Aspect_Depends                      => True,
827      Aspect_Global                       => True,
828      Aspect_Part_Of                      => True,
829      others                              => False);
830
831   ---------------------------------------------------
832   -- Handling of Aspect Specifications in the Tree --
833   ---------------------------------------------------
834
835   --  Several kinds of declaration node permit aspect specifications in Ada
836   --  2012 mode. If there was room in all the corresponding declaration nodes,
837   --  we could just have a field Aspect_Specifications pointing to a list of
838   --  nodes for the aspects (N_Aspect_Specification nodes). But there isn't
839   --  room, so we adopt a different approach.
840
841   --  The following subprograms provide access to a specialized interface
842   --  implemented internally with a hash table in the body, that provides
843   --  access to aspect specifications.
844
845   function Aspect_Specifications (N : Node_Id) return List_Id;
846   --  Given a node N, returns the list of N_Aspect_Specification nodes that
847   --  are attached to this declaration node. If the node is in the class of
848   --  declaration nodes that permit aspect specifications, as defined by the
849   --  predicate above, and if their Has_Aspects flag is set to True, then this
850   --  will always be a non-empty list. If this flag is set to False, then
851   --  No_List is returned. Normally, the only nodes that have Has_Aspects set
852   --  True are the nodes for which Permits_Aspect_Specifications would return
853   --  True (i.e. the declaration nodes defined in the RM as permitting the
854   --  presence of Aspect_Specifications). However, it is possible for the
855   --  flag Has_Aspects to be set on other nodes as a result of Rewrite and
856   --  Replace calls, and this function may be used to retrieve the aspect
857   --  specifications for the original rewritten node in such cases.
858
859   function Aspects_On_Body_Or_Stub_OK (N : Node_Id) return Boolean;
860   --  N denotes a body [stub] with aspects. Determine whether all aspects of N
861   --  are allowed to appear on a body [stub].
862
863   procedure Exchange_Aspects (N1 : Node_Id; N2 : Node_Id);
864   --  Exchange the aspect specifications of two nodes. If either node lacks an
865   --  aspect specification list, the routine has no effect. It is assumed that
866   --  both nodes can support aspects.
867
868   function Find_Aspect (Id : Entity_Id; A : Aspect_Id) return Node_Id;
869   --  Find the aspect specification of aspect A associated with entity I.
870   --  Return Empty if Id does not have the requested aspect.
871
872   function Find_Value_Of_Aspect
873     (Id : Entity_Id;
874      A  : Aspect_Id) return Node_Id;
875   --  Find the value of aspect A associated with entity Id. Return Empty if
876   --  Id does not have the requested aspect.
877
878   function Has_Aspect (Id : Entity_Id; A : Aspect_Id) return Boolean;
879   --  Determine whether entity Id has aspect A
880
881   procedure Move_Aspects (From : Node_Id; To : Node_Id);
882   --  Relocate the aspect specifications of node From to node To. On entry it
883   --  is assumed that To does not have aspect specifications. If From has no
884   --  aspects, the routine has no effect.
885
886   procedure Move_Or_Merge_Aspects (From : Node_Id; To : Node_Id);
887   --  Relocate the aspect specifications of node From to node To. If To has
888   --  aspects, the aspects of From are appended to the aspects of To. If From
889   --  has no aspects, the routine has no effect. Special behavior:
890   --    * When node From denotes a subprogram body stub without a previous
891   --      declaration, the only aspects relocated to node To are those found
892   --      in table Aspect_On_Body_Or_Stub_OK.
893   --    * When node From denotes a single synchronized type declaration, the
894   --      only aspects relocated to node To are those found in table
895   --      Aspect_On_Anonymous_Object_OK.
896
897   function Permits_Aspect_Specifications (N : Node_Id) return Boolean;
898   --  Returns True if the node N is a declaration node that permits aspect
899   --  specifications in the grammar. It is possible for other nodes to have
900   --  aspect specifications as a result of Rewrite or Replace calls.
901
902   procedure Remove_Aspects (N : Node_Id);
903   --  Delete the aspect specifications associated with node N. If the node has
904   --  no aspects, the routine has no effect.
905
906   function Same_Aspect (A1 : Aspect_Id; A2 : Aspect_Id) return Boolean;
907   --  Returns True if A1 and A2 are (essentially) the same aspect. This is not
908   --  a simple equality test because e.g. Post and Postcondition are the same.
909   --  This is used for detecting duplicate aspects.
910
911   procedure Set_Aspect_Specifications (N : Node_Id; L : List_Id);
912   --  The node N must be in the class of declaration nodes that permit aspect
913   --  specifications and the Has_Aspects flag must be False on entry. L must
914   --  be a non-empty list of N_Aspect_Specification nodes. This procedure sets
915   --  the Has_Aspects flag to True, and makes an entry that can be retrieved
916   --  by a subsequent Aspect_Specifications call. It is an error to call this
917   --  procedure with a node that does not permit aspect specifications, or a
918   --  node that has its Has_Aspects flag set True on entry, or with L being an
919   --  empty list or No_List.
920
921   procedure Tree_Read;
922   --  Reads contents of Aspect_Specifications hash table from the tree file
923
924   procedure Tree_Write;
925   --  Writes contents of Aspect_Specifications hash table to the tree file
926
927end Aspects;
928