gcc/ada/aspects.ads

   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) 2010-2017, 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
  67 with Namet;   use Namet;
  68 with Snames;  use Snames;
  69 with Types;   use Types;
  70
  71 package 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_Queue_Length,              -- GNAT
 120       Aspect_Object_Size,                   -- GNAT
 121       Aspect_Obsolescent,                   -- GNAT
 122       Aspect_Output,
 123       Aspect_Part_Of,                       -- GNAT
 124       Aspect_Post,
 125       Aspect_Postcondition,
 126       Aspect_Pre,
 127       Aspect_Precondition,
 128       Aspect_Predicate,                     -- GNAT
 129       Aspect_Predicate_Failure,
 130       Aspect_Priority,
 131       Aspect_Read,
 132       Aspect_Refined_Depends,               -- GNAT
 133       Aspect_Refined_Global,                -- GNAT
 134       Aspect_Refined_Post,                  -- GNAT
 135       Aspect_Refined_State,                 -- GNAT
 136       Aspect_Relative_Deadline,
 137       Aspect_Scalar_Storage_Order,          -- GNAT
 138       Aspect_Secondary_Stack_Size,          -- GNAT
 139       Aspect_Simple_Storage_Pool,           -- GNAT
 140       Aspect_Size,
 141       Aspect_Small,
 142       Aspect_SPARK_Mode,                    -- GNAT
 143       Aspect_Static_Predicate,
 144       Aspect_Storage_Pool,
 145       Aspect_Storage_Size,
 146       Aspect_Stream_Size,
 147       Aspect_Suppress,
 148       Aspect_Synchronization,
 149       Aspect_Test_Case,                     -- GNAT
 150       Aspect_Type_Invariant,
 151       Aspect_Unimplemented,                 -- GNAT
 152       Aspect_Unsuppress,
 153       Aspect_Value_Size,                    -- GNAT
 154       Aspect_Variable_Indexing,
 155       Aspect_Volatile_Function,             -- GNAT
 156       Aspect_Warnings,                      -- GNAT
 157       Aspect_Write,
 158
 159       --  The following aspects correspond to library unit pragmas
 160
 161       Aspect_All_Calls_Remote,
 162       Aspect_Elaborate_Body,
 163       Aspect_No_Elaboration_Code_All,       -- GNAT
 164       Aspect_Preelaborate,
 165       Aspect_Pure,
 166       Aspect_Remote_Call_Interface,
 167       Aspect_Remote_Types,
 168       Aspect_Shared_Passive,
 169       Aspect_Universal_Data,                -- GNAT
 170
 171       --  Remaining aspects have a static boolean value that turns the aspect
 172       --  on or off. They all correspond to pragmas, but are only converted to
 173       --  the pragmas where the value is True. A value of False normally means
 174       --  that the aspect is ignored, except in the case of derived types where
 175       --  the aspect value is inherited from the parent, in which case, we do
 176       --  not allow False if we inherit a True value from the parent.
 177
 178       Aspect_Asynchronous,
 179       Aspect_Atomic,
 180       Aspect_Atomic_Components,
 181       Aspect_Disable_Controlled,            -- GNAT
 182       Aspect_Discard_Names,
 183       Aspect_Export,
 184       Aspect_Favor_Top_Level,               -- GNAT
 185       Aspect_Independent,
 186       Aspect_Independent_Components,
 187       Aspect_Import,
 188       Aspect_Inline,
 189       Aspect_Inline_Always,                 -- GNAT
 190       Aspect_Interrupt_Handler,
 191       Aspect_Lock_Free,                     -- GNAT
 192       Aspect_No_Inline,                     -- GNAT
 193       Aspect_No_Return,
 194       Aspect_No_Tagged_Streams,             -- GNAT
 195       Aspect_Pack,
 196       Aspect_Persistent_BSS,                -- GNAT
 197       Aspect_Preelaborable_Initialization,
 198       Aspect_Pure_Function,                 -- GNAT
 199       Aspect_Remote_Access_Type,            -- GNAT
 200       Aspect_Shared,                        -- GNAT (equivalent to Atomic)
 201       Aspect_Simple_Storage_Pool_Type,      -- GNAT
 202       Aspect_Suppress_Debug_Info,           -- GNAT
 203       Aspect_Suppress_Initialization,       -- GNAT
 204       Aspect_Thread_Local_Storage,          -- GNAT
 205       Aspect_Unchecked_Union,
 206       Aspect_Universal_Aliasing,            -- GNAT
 207       Aspect_Unmodified,                    -- GNAT
 208       Aspect_Unreferenced,                  -- GNAT
 209       Aspect_Unreferenced_Objects,          -- GNAT
 210       Aspect_Volatile,
 211       Aspect_Volatile_Components,
 212       Aspect_Volatile_Full_Access);         -- GNAT
 213
 214    subtype Aspect_Id_Exclude_No_Aspect is
 215      Aspect_Id range Aspect_Id'Succ (No_Aspect) .. Aspect_Id'Last;
 216    --  Aspect_Id's excluding No_Aspect
 217
 218    --  The following array indicates aspects that accept 'Class
 219
 220    Class_Aspect_OK : constant array (Aspect_Id) of Boolean :=
 221      (Aspect_Input          => True,
 222       Aspect_Invariant      => True,
 223       Aspect_Output         => True,
 224       Aspect_Pre            => True,
 225       Aspect_Predicate      => True,
 226       Aspect_Post           => True,
 227       Aspect_Read           => True,
 228       Aspect_Write          => True,
 229       Aspect_Type_Invariant => True,
 230       others                => False);
 231
 232    --  The following array identifies all implementation defined aspects
 233
 234    Implementation_Defined_Aspect : constant array (Aspect_Id) of Boolean :=
 235      (Aspect_Abstract_State             => True,
 236       Aspect_Annotate                   => True,
 237       Aspect_Async_Readers              => True,
 238       Aspect_Async_Writers              => True,
 239       Aspect_Constant_After_Elaboration => True,
 240       Aspect_Contract_Cases             => True,
 241       Aspect_Depends                    => True,
 242       Aspect_Dimension                  => True,
 243       Aspect_Dimension_System           => True,
 244       Aspect_Effective_Reads            => True,
 245       Aspect_Effective_Writes           => True,
 246       Aspect_Extensions_Visible         => True,
 247       Aspect_Favor_Top_Level            => True,
 248       Aspect_Ghost                      => True,
 249       Aspect_Global                     => True,
 250       Aspect_Inline_Always              => True,
 251       Aspect_Invariant                  => True,
 252       Aspect_Lock_Free                  => True,
 253       Aspect_Max_Queue_Length           => True,
 254       Aspect_Object_Size                => True,
 255       Aspect_Persistent_BSS             => True,
 256       Aspect_Predicate                  => True,
 257       Aspect_Pure_Function              => True,
 258       Aspect_Remote_Access_Type         => True,
 259       Aspect_Scalar_Storage_Order       => True,
 260       Aspect_Secondary_Stack_Size       => True,
 261       Aspect_Shared                     => True,
 262       Aspect_Simple_Storage_Pool        => True,
 263       Aspect_Simple_Storage_Pool_Type   => True,
 264       Aspect_Suppress_Debug_Info        => True,
 265       Aspect_Suppress_Initialization    => True,
 266       Aspect_Thread_Local_Storage       => True,
 267       Aspect_Test_Case                  => True,
 268       Aspect_Universal_Aliasing         => True,
 269       Aspect_Universal_Data             => True,
 270       Aspect_Unmodified                 => True,
 271       Aspect_Unreferenced               => True,
 272       Aspect_Unreferenced_Objects       => True,
 273       Aspect_Value_Size                 => True,
 274       Aspect_Volatile_Function          => True,
 275       Aspect_Warnings                   => True,
 276       others                            => False);
 277
 278    --  The following array indicates aspects for which multiple occurrences of
 279    --  the same aspect attached to the same declaration are allowed.
 280
 281    No_Duplicates_Allowed : constant array (Aspect_Id) of Boolean :=
 282      (Aspect_Annotate  => False,
 283       Aspect_Test_Case => False,
 284       others           => True);
 285
 286    --  The following subtype defines aspects corresponding to library unit
 287    --  pragmas, these can only validly appear as aspects for library units,
 288    --  and result in a corresponding pragma being inserted immediately after
 289    --  the occurrence of the aspect.
 290
 291    subtype Library_Unit_Aspects is
 292      Aspect_Id range Aspect_All_Calls_Remote .. Aspect_Universal_Data;
 293
 294    --  The following subtype defines aspects accepting an optional static
 295    --  boolean parameter indicating if the aspect should be active or
 296    --  cancelling. If the parameter is missing the effective value is True,
 297    --  enabling the aspect. If the parameter is present it must be a static
 298    --  expression of type Standard.Boolean. If the value is True, then the
 299    --  aspect is enabled. If it is False, the aspect is disabled.
 300
 301    subtype Boolean_Aspects is
 302      Aspect_Id range Aspect_Asynchronous .. Aspect_Id'Last;
 303
 304    subtype Pre_Post_Aspects is
 305      Aspect_Id range Aspect_Post .. Aspect_Precondition;
 306
 307    --  The following type is used for indicating allowed expression forms
 308
 309    type Aspect_Expression is
 310      (Expression,             -- Required expression
 311       Name,                   -- Required name
 312       Optional_Expression,    -- Optional boolean expression
 313       Optional_Name);         -- Optional name
 314
 315    --  The following array indicates what argument type is required
 316
 317    Aspect_Argument : constant array (Aspect_Id) of Aspect_Expression :=
 318      (No_Aspect                         => Optional_Expression,
 319       Aspect_Abstract_State             => Expression,
 320       Aspect_Address                    => Expression,
 321       Aspect_Alignment                  => Expression,
 322       Aspect_Annotate                   => Expression,
 323       Aspect_Async_Readers              => Optional_Expression,
 324       Aspect_Async_Writers              => Optional_Expression,
 325       Aspect_Attach_Handler             => Expression,
 326       Aspect_Bit_Order                  => Expression,
 327       Aspect_Component_Size             => Expression,
 328       Aspect_Constant_After_Elaboration => Optional_Expression,
 329       Aspect_Constant_Indexing          => Name,
 330       Aspect_Contract_Cases             => Expression,
 331       Aspect_Convention                 => Name,
 332       Aspect_CPU                        => Expression,
 333       Aspect_Default_Component_Value    => Expression,
 334       Aspect_Default_Initial_Condition  => Optional_Expression,
 335       Aspect_Default_Iterator           => Name,
 336       Aspect_Default_Storage_Pool       => Expression,
 337       Aspect_Default_Value              => Expression,
 338       Aspect_Depends                    => Expression,
 339       Aspect_Dimension                  => Expression,
 340       Aspect_Dimension_System           => Expression,
 341       Aspect_Dispatching_Domain         => Expression,
 342       Aspect_Dynamic_Predicate          => Expression,
 343       Aspect_Effective_Reads            => Optional_Expression,
 344       Aspect_Effective_Writes           => Optional_Expression,
 345       Aspect_Extensions_Visible         => Optional_Expression,
 346       Aspect_External_Name              => Expression,
 347       Aspect_External_Tag               => Expression,
 348       Aspect_Ghost                      => Optional_Expression,
 349       Aspect_Global                     => Expression,
 350       Aspect_Implicit_Dereference       => Name,
 351       Aspect_Initial_Condition          => Expression,
 352       Aspect_Initializes                => Expression,
 353       Aspect_Input                      => Name,
 354       Aspect_Interrupt_Priority         => Expression,
 355       Aspect_Invariant                  => Expression,
 356       Aspect_Iterable                   => Expression,
 357       Aspect_Iterator_Element           => Name,
 358       Aspect_Link_Name                  => Expression,
 359       Aspect_Linker_Section             => Expression,
 360       Aspect_Machine_Radix              => Expression,
 361       Aspect_Max_Queue_Length           => Expression,
 362       Aspect_Object_Size                => Expression,
 363       Aspect_Obsolescent                => Optional_Expression,
 364       Aspect_Output                     => Name,
 365       Aspect_Part_Of                    => Expression,
 366       Aspect_Post                       => Expression,
 367       Aspect_Postcondition              => Expression,
 368       Aspect_Pre                        => Expression,
 369       Aspect_Precondition               => Expression,
 370       Aspect_Predicate                  => Expression,
 371       Aspect_Predicate_Failure          => Expression,
 372       Aspect_Priority                   => Expression,
 373       Aspect_Read                       => Name,
 374       Aspect_Refined_Depends            => Expression,
 375       Aspect_Refined_Global             => Expression,
 376       Aspect_Refined_Post               => Expression,
 377       Aspect_Refined_State              => Expression,
 378       Aspect_Relative_Deadline          => Expression,
 379       Aspect_Scalar_Storage_Order       => Expression,
 380       Aspect_Secondary_Stack_Size       => Expression,
 381       Aspect_Simple_Storage_Pool        => Name,
 382       Aspect_Size                       => Expression,
 383       Aspect_Small                      => Expression,
 384       Aspect_SPARK_Mode                 => Optional_Name,
 385       Aspect_Static_Predicate           => Expression,
 386       Aspect_Storage_Pool               => Name,
 387       Aspect_Storage_Size               => Expression,
 388       Aspect_Stream_Size                => Expression,
 389       Aspect_Suppress                   => Name,
 390       Aspect_Synchronization            => Name,
 391       Aspect_Test_Case                  => Expression,
 392       Aspect_Type_Invariant             => Expression,
 393       Aspect_Unimplemented              => Optional_Expression,
 394       Aspect_Unsuppress                 => Name,
 395       Aspect_Value_Size                 => Expression,
 396       Aspect_Variable_Indexing          => Name,
 397       Aspect_Volatile_Function          => Optional_Expression,
 398       Aspect_Warnings                   => Name,
 399       Aspect_Write                      => Name,
 400
 401       Boolean_Aspects                   => Optional_Expression,
 402       Library_Unit_Aspects              => Optional_Expression);
 403
 404    -----------------------------------------
 405    -- Table Linking Names and Aspect_Id's --
 406    -----------------------------------------
 407
 408    --  Table linking aspect names and id's
 409
 410    Aspect_Names : constant array (Aspect_Id) of Name_Id :=
 411      (No_Aspect                           => No_Name,
 412       Aspect_Abstract_State               => Name_Abstract_State,
 413       Aspect_Address                      => Name_Address,
 414       Aspect_Alignment                    => Name_Alignment,
 415       Aspect_All_Calls_Remote             => Name_All_Calls_Remote,
 416       Aspect_Annotate                     => Name_Annotate,
 417       Aspect_Async_Readers                => Name_Async_Readers,
 418       Aspect_Async_Writers                => Name_Async_Writers,
 419       Aspect_Asynchronous                 => Name_Asynchronous,
 420       Aspect_Atomic                       => Name_Atomic,
 421       Aspect_Atomic_Components            => Name_Atomic_Components,
 422       Aspect_Attach_Handler               => Name_Attach_Handler,
 423       Aspect_Bit_Order                    => Name_Bit_Order,
 424       Aspect_Component_Size               => Name_Component_Size,
 425       Aspect_Constant_After_Elaboration   => Name_Constant_After_Elaboration,
 426       Aspect_Constant_Indexing            => Name_Constant_Indexing,
 427       Aspect_Contract_Cases               => Name_Contract_Cases,
 428       Aspect_Convention                   => Name_Convention,
 429       Aspect_CPU                          => Name_CPU,
 430       Aspect_Default_Component_Value      => Name_Default_Component_Value,
 431       Aspect_Default_Initial_Condition    => Name_Default_Initial_Condition,
 432       Aspect_Default_Iterator             => Name_Default_Iterator,
 433       Aspect_Default_Storage_Pool         => Name_Default_Storage_Pool,
 434       Aspect_Default_Value                => Name_Default_Value,
 435       Aspect_Depends                      => Name_Depends,
 436       Aspect_Dimension                    => Name_Dimension,
 437       Aspect_Dimension_System             => Name_Dimension_System,
 438       Aspect_Disable_Controlled           => Name_Disable_Controlled,
 439       Aspect_Discard_Names                => Name_Discard_Names,
 440       Aspect_Dispatching_Domain           => Name_Dispatching_Domain,
 441       Aspect_Dynamic_Predicate            => Name_Dynamic_Predicate,
 442       Aspect_Effective_Reads              => Name_Effective_Reads,
 443       Aspect_Effective_Writes             => Name_Effective_Writes,
 444       Aspect_Elaborate_Body               => Name_Elaborate_Body,
 445       Aspect_Export                       => Name_Export,
 446       Aspect_Extensions_Visible           => Name_Extensions_Visible,
 447       Aspect_External_Name                => Name_External_Name,
 448       Aspect_External_Tag                 => Name_External_Tag,
 449       Aspect_Favor_Top_Level              => Name_Favor_Top_Level,
 450       Aspect_Ghost                        => Name_Ghost,
 451       Aspect_Global                       => Name_Global,
 452       Aspect_Implicit_Dereference         => Name_Implicit_Dereference,
 453       Aspect_Import                       => Name_Import,
 454       Aspect_Independent                  => Name_Independent,
 455       Aspect_Independent_Components       => Name_Independent_Components,
 456       Aspect_Inline                       => Name_Inline,
 457       Aspect_Inline_Always                => Name_Inline_Always,
 458       Aspect_Initial_Condition            => Name_Initial_Condition,
 459       Aspect_Initializes                  => Name_Initializes,
 460       Aspect_Input                        => Name_Input,
 461       Aspect_Interrupt_Handler            => Name_Interrupt_Handler,
 462       Aspect_Interrupt_Priority           => Name_Interrupt_Priority,
 463       Aspect_Invariant                    => Name_Invariant,
 464       Aspect_Iterator_Element             => Name_Iterator_Element,
 465       Aspect_Iterable                     => Name_Iterable,
 466       Aspect_Link_Name                    => Name_Link_Name,
 467       Aspect_Linker_Section               => Name_Linker_Section,
 468       Aspect_Lock_Free                    => Name_Lock_Free,
 469       Aspect_Machine_Radix                => Name_Machine_Radix,
 470       Aspect_Max_Queue_Length             => Name_Max_Queue_Length,
 471       Aspect_No_Elaboration_Code_All      => Name_No_Elaboration_Code_All,
 472       Aspect_No_Inline                    => Name_No_Inline,
 473       Aspect_No_Return                    => Name_No_Return,
 474       Aspect_No_Tagged_Streams            => Name_No_Tagged_Streams,
 475       Aspect_Object_Size                  => Name_Object_Size,
 476       Aspect_Obsolescent                  => Name_Obsolescent,
 477       Aspect_Output                       => Name_Output,
 478       Aspect_Pack                         => Name_Pack,
 479       Aspect_Part_Of                      => Name_Part_Of,
 480       Aspect_Persistent_BSS               => Name_Persistent_BSS,
 481       Aspect_Post                         => Name_Post,
 482       Aspect_Postcondition                => Name_Postcondition,
 483       Aspect_Pre                          => Name_Pre,
 484       Aspect_Precondition                 => Name_Precondition,
 485       Aspect_Predicate                    => Name_Predicate,
 486       Aspect_Predicate_Failure            => Name_Predicate_Failure,
 487       Aspect_Preelaborable_Initialization => Name_Preelaborable_Initialization,
 488       Aspect_Preelaborate                 => Name_Preelaborate,
 489       Aspect_Priority                     => Name_Priority,
 490       Aspect_Pure                         => Name_Pure,
 491       Aspect_Pure_Function                => Name_Pure_Function,
 492       Aspect_Read                         => Name_Read,
 493       Aspect_Refined_Depends              => Name_Refined_Depends,
 494       Aspect_Refined_Global               => Name_Refined_Global,
 495       Aspect_Refined_Post                 => Name_Refined_Post,
 496       Aspect_Refined_State                => Name_Refined_State,
 497       Aspect_Relative_Deadline            => Name_Relative_Deadline,
 498       Aspect_Remote_Access_Type           => Name_Remote_Access_Type,
 499       Aspect_Remote_Call_Interface        => Name_Remote_Call_Interface,
 500       Aspect_Remote_Types                 => Name_Remote_Types,
 501       Aspect_Scalar_Storage_Order         => Name_Scalar_Storage_Order,
 502       Aspect_Secondary_Stack_Size         => Name_Secondary_Stack_Size,
 503       Aspect_Shared                       => Name_Shared,
 504       Aspect_Shared_Passive               => Name_Shared_Passive,
 505       Aspect_Simple_Storage_Pool          => Name_Simple_Storage_Pool,
 506       Aspect_Simple_Storage_Pool_Type     => Name_Simple_Storage_Pool_Type,
 507       Aspect_Size                         => Name_Size,
 508       Aspect_Small                        => Name_Small,
 509       Aspect_SPARK_Mode                   => Name_SPARK_Mode,
 510       Aspect_Static_Predicate             => Name_Static_Predicate,
 511       Aspect_Storage_Pool                 => Name_Storage_Pool,
 512       Aspect_Storage_Size                 => Name_Storage_Size,
 513       Aspect_Stream_Size                  => Name_Stream_Size,
 514       Aspect_Suppress                     => Name_Suppress,
 515       Aspect_Suppress_Debug_Info          => Name_Suppress_Debug_Info,
 516       Aspect_Suppress_Initialization      => Name_Suppress_Initialization,
 517       Aspect_Thread_Local_Storage         => Name_Thread_Local_Storage,
 518       Aspect_Synchronization              => Name_Synchronization,
 519       Aspect_Test_Case                    => Name_Test_Case,
 520       Aspect_Type_Invariant               => Name_Type_Invariant,
 521       Aspect_Unchecked_Union              => Name_Unchecked_Union,
 522       Aspect_Unimplemented                => Name_Unimplemented,
 523       Aspect_Universal_Aliasing           => Name_Universal_Aliasing,
 524       Aspect_Universal_Data               => Name_Universal_Data,
 525       Aspect_Unmodified                   => Name_Unmodified,
 526       Aspect_Unreferenced                 => Name_Unreferenced,
 527       Aspect_Unreferenced_Objects         => Name_Unreferenced_Objects,
 528       Aspect_Unsuppress                   => Name_Unsuppress,
 529       Aspect_Value_Size                   => Name_Value_Size,
 530       Aspect_Variable_Indexing            => Name_Variable_Indexing,
 531       Aspect_Volatile                     => Name_Volatile,
 532       Aspect_Volatile_Components          => Name_Volatile_Components,
 533       Aspect_Volatile_Full_Access         => Name_Volatile_Full_Access,
 534       Aspect_Volatile_Function            => Name_Volatile_Function,
 535       Aspect_Warnings                     => Name_Warnings,
 536       Aspect_Write                        => Name_Write);
 537
 538    function Get_Aspect_Id (Name : Name_Id) return Aspect_Id;
 539    pragma Inline (Get_Aspect_Id);
 540    --  Given a name Nam, returns the corresponding aspect id value. If the name
 541    --  does not match any aspect, then No_Aspect is returned as the result.
 542
 543    function Get_Aspect_Id (Aspect : Node_Id) return Aspect_Id;
 544    pragma Inline (Get_Aspect_Id);
 545    --  Given an aspect specification, return the corresponding aspect_id value.
 546    --  If the name does not match any aspect, return No_Aspect.
 547
 548    ------------------------------------
 549    -- Delaying Evaluation of Aspects --
 550    ------------------------------------
 551
 552    --  The RM requires that all language defined aspects taking an expression
 553    --  delay evaluation of the expression till the freeze point of the entity
 554    --  to which the aspect applies. This allows forward references, and is of
 555    --  use for example in connection with preconditions and postconditions
 556    --  where the requirement of making all references in contracts to local
 557    --  functions be backwards references would be onerous.
 558
 559    --  For consistency, even attributes like Size are delayed, so we can do:
 560
 561    --    type A is range 1 .. 10
 562    --      with Size => Not_Defined_Yet;
 563    --    ..
 564    --    Not_Defined_Yet : constant := 64;
 565
 566    --  Resulting in A having a size of 64, which gets set when A is frozen.
 567    --  Furthermore, we can have a situation like
 568
 569    --    type A is range 1 .. 10
 570    --      with Size => Not_Defined_Yet;
 571    --    ..
 572    --    type B is new A;
 573    --    ..
 574    --    Not_Defined_Yet : constant := 64;
 575
 576    --  where the Size of A is considered to have been previously specified at
 577    --  the point of derivation, even though the actual value of the size is
 578    --  not known yet, and in this example B inherits the size value of 64.
 579
 580    --  Our normal implementation model (prior to Ada 2012) was simply to copy
 581    --  inheritable attributes at the point of derivation. Then any subsequent
 582    --  representation items apply either to the parent type, not affecting the
 583    --  derived type, or to the derived type, not affecting the parent type.
 584
 585    --  To deal with the delayed aspect case, we use two flags. The first is
 586    --  set on the parent type if it has delayed representation aspects. This
 587    --  flag Has_Delayed_Rep_Aspects indicates that if we derive from this type
 588    --  we have to worry about making sure we inherit any delayed aspects. The
 589    --  second flag is set on a derived type: May_Have_Inherited_Rep_Aspects
 590    --  is set if the parent type has Has_Delayed_Rep_Aspects set.
 591
 592    --  When we freeze a derived type, if the May_Have_Inherited_Rep_Aspects
 593    --  flag is set, then we call Freeze.Inherit_Delayed_Rep_Aspects when
 594    --  the derived type is frozen, which deals with the necessary copying of
 595    --  information from the parent type, which must be frozen at that point
 596    --  (since freezing the derived type first freezes the parent type).
 597
 598    --  SPARK 2014 aspects do not follow the general delay mechanism as they
 599    --  act as annotations and cannot modify the attributes of their related
 600    --  constructs. To handle forward references in such aspects, the compiler
 601    --  delays the analysis of their respective pragmas by collecting them in
 602    --  N_Contract nodes. The pragmas are then analyzed at the end of the
 603    --  declarative region containing the related construct. For details,
 604    --  see routines Analyze_xxx_In_Decl_Part.
 605
 606    --  The following shows which aspects are delayed. There are three cases:
 607
 608    type Delay_Type is
 609      (Always_Delay,
 610       --  This aspect is not a representation aspect that can be inherited and
 611       --  is always delayed, as required by the language definition.
 612
 613       Never_Delay,
 614       --  There are two cases. There are language defined aspects like
 615       --  Convention where the "expression" is simply an uninterpreted
 616       --  identifier, and there is no issue of evaluating it and thus no
 617       --  issue of delaying the evaluation. The second case is implementation
 618       --  defined aspects where we have decided that we don't want to allow
 619       --  delays (and for our own aspects we can do what we like).
 620
 621       Rep_Aspect);
 622       --  These are the cases of representation aspects that are in general
 623       --  delayed, and where there is a potential issue of derived types that
 624       --  inherit delayed representation values.
 625
 626    --  Note: even if this table indicates that an aspect is delayed, we never
 627    --  delay Boolean aspects that have a missing expression (taken as True),
 628    --  or expressions for delayed rep items that consist of an integer literal
 629    --  (most cases of Size etc. in practice), since in these cases we know we
 630    --  can get the value of the expression without delay. Note that we still
 631    --  need to delay Boolean aspects that are specifically set to True:
 632
 633    --     type R is array (0 .. 31) of Boolean
 634    --       with Pack => True;
 635    --     True : constant Boolean := False;
 636
 637    --  This is nonsense, but we need to make it work and result in R not
 638    --  being packed, and if we have something like:
 639
 640    --     type R is array (0 .. 31) of Boolean
 641    --       with Pack => True;
 642    --     RR : R;
 643    --     True : constant Boolean := False;
 644
 645    --  This is illegal because the visibility of True changes after the freeze
 646    --  point, which is not allowed, and we need the delay mechanism to properly
 647    --  diagnose this error.
 648
 649    Aspect_Delay : constant array (Aspect_Id) of Delay_Type :=
 650      (No_Aspect                           => Always_Delay,
 651       Aspect_Address                      => Always_Delay,
 652       Aspect_All_Calls_Remote             => Always_Delay,
 653       Aspect_Asynchronous                 => Always_Delay,
 654       Aspect_Attach_Handler               => Always_Delay,
 655       Aspect_Constant_Indexing            => Always_Delay,
 656       Aspect_CPU                          => Always_Delay,
 657       Aspect_Default_Iterator             => Always_Delay,
 658       Aspect_Default_Storage_Pool         => Always_Delay,
 659       Aspect_Default_Value                => Always_Delay,
 660       Aspect_Default_Component_Value      => Always_Delay,
 661       Aspect_Discard_Names                => Always_Delay,
 662       Aspect_Dispatching_Domain           => Always_Delay,
 663       Aspect_Dynamic_Predicate            => Always_Delay,
 664       Aspect_Elaborate_Body               => Always_Delay,
 665       Aspect_External_Name                => Always_Delay,
 666       Aspect_External_Tag                 => Always_Delay,
 667       Aspect_Favor_Top_Level              => Always_Delay,
 668       Aspect_Implicit_Dereference         => Always_Delay,
 669       Aspect_Independent                  => Always_Delay,
 670       Aspect_Independent_Components       => Always_Delay,
 671       Aspect_Inline                       => Always_Delay,
 672       Aspect_Inline_Always                => Always_Delay,
 673       Aspect_Input                        => Always_Delay,
 674       Aspect_Interrupt_Handler            => Always_Delay,
 675       Aspect_Interrupt_Priority           => Always_Delay,
 676       Aspect_Invariant                    => Always_Delay,
 677       Aspect_Iterable                     => Always_Delay,
 678       Aspect_Iterator_Element             => Always_Delay,
 679       Aspect_Link_Name                    => Always_Delay,
 680       Aspect_Linker_Section               => Always_Delay,
 681       Aspect_Lock_Free                    => Always_Delay,
 682       Aspect_No_Inline                    => Always_Delay,
 683       Aspect_No_Return                    => Always_Delay,
 684       Aspect_Output                       => Always_Delay,
 685       Aspect_Persistent_BSS               => Always_Delay,
 686       Aspect_Post                         => Always_Delay,
 687       Aspect_Postcondition                => Always_Delay,
 688       Aspect_Pre                          => Always_Delay,
 689       Aspect_Precondition                 => Always_Delay,
 690       Aspect_Predicate                    => Always_Delay,
 691       Aspect_Predicate_Failure            => Always_Delay,
 692       Aspect_Preelaborable_Initialization => Always_Delay,
 693       Aspect_Preelaborate                 => Always_Delay,
 694       Aspect_Priority                     => Always_Delay,
 695       Aspect_Pure                         => Always_Delay,
 696       Aspect_Pure_Function                => Always_Delay,
 697       Aspect_Read                         => Always_Delay,
 698       Aspect_Relative_Deadline            => Always_Delay,
 699       Aspect_Remote_Access_Type           => Always_Delay,
 700       Aspect_Remote_Call_Interface        => Always_Delay,
 701       Aspect_Remote_Types                 => Always_Delay,
 702       Aspect_Secondary_Stack_Size         => Always_Delay,
 703       Aspect_Shared                       => Always_Delay,
 704       Aspect_Shared_Passive               => Always_Delay,
 705       Aspect_Simple_Storage_Pool          => Always_Delay,
 706       Aspect_Simple_Storage_Pool_Type     => Always_Delay,
 707       Aspect_Static_Predicate             => Always_Delay,
 708       Aspect_Storage_Pool                 => Always_Delay,
 709       Aspect_Stream_Size                  => Always_Delay,
 710       Aspect_Suppress                     => Always_Delay,
 711       Aspect_Suppress_Debug_Info          => Always_Delay,
 712       Aspect_Suppress_Initialization      => Always_Delay,
 713       Aspect_Thread_Local_Storage         => Always_Delay,
 714       Aspect_Type_Invariant               => Always_Delay,
 715       Aspect_Unchecked_Union              => Always_Delay,
 716       Aspect_Universal_Aliasing           => Always_Delay,
 717       Aspect_Universal_Data               => Always_Delay,
 718       Aspect_Unmodified                   => Always_Delay,
 719       Aspect_Unreferenced                 => Always_Delay,
 720       Aspect_Unreferenced_Objects         => Always_Delay,
 721       Aspect_Unsuppress                   => Always_Delay,
 722       Aspect_Variable_Indexing            => Always_Delay,
 723       Aspect_Write                        => Always_Delay,
 724
 725       Aspect_Abstract_State               => Never_Delay,
 726       Aspect_Annotate                     => Never_Delay,
 727       Aspect_Async_Readers                => Never_Delay,
 728       Aspect_Async_Writers                => Never_Delay,
 729       Aspect_Constant_After_Elaboration   => Never_Delay,
 730       Aspect_Contract_Cases               => Never_Delay,
 731       Aspect_Convention                   => Never_Delay,
 732       Aspect_Default_Initial_Condition    => Never_Delay,
 733       Aspect_Depends                      => Never_Delay,
 734       Aspect_Dimension                    => Never_Delay,
 735       Aspect_Dimension_System             => Never_Delay,
 736       Aspect_Disable_Controlled           => Never_Delay,
 737       Aspect_Effective_Reads              => Never_Delay,
 738       Aspect_Effective_Writes             => Never_Delay,
 739       Aspect_Export                       => Never_Delay,
 740       Aspect_Extensions_Visible           => Never_Delay,
 741       Aspect_Ghost                        => Never_Delay,
 742       Aspect_Global                       => Never_Delay,
 743       Aspect_Import                       => Never_Delay,
 744       Aspect_Initial_Condition            => Never_Delay,
 745       Aspect_Initializes                  => Never_Delay,
 746       Aspect_Max_Queue_Length             => Never_Delay,
 747       Aspect_No_Elaboration_Code_All      => Never_Delay,
 748       Aspect_No_Tagged_Streams            => Never_Delay,
 749       Aspect_Obsolescent                  => Never_Delay,
 750       Aspect_Part_Of                      => Never_Delay,
 751       Aspect_Refined_Depends              => Never_Delay,
 752       Aspect_Refined_Global               => Never_Delay,
 753       Aspect_Refined_Post                 => Never_Delay,
 754       Aspect_Refined_State                => Never_Delay,
 755       Aspect_SPARK_Mode                   => Never_Delay,
 756       Aspect_Synchronization              => Never_Delay,
 757       Aspect_Test_Case                    => Never_Delay,
 758       Aspect_Unimplemented                => Never_Delay,
 759       Aspect_Volatile_Function            => Never_Delay,
 760       Aspect_Warnings                     => Never_Delay,
 761
 762       Aspect_Alignment                    => Rep_Aspect,
 763       Aspect_Atomic                       => Rep_Aspect,
 764       Aspect_Atomic_Components            => Rep_Aspect,
 765       Aspect_Bit_Order                    => Rep_Aspect,
 766       Aspect_Component_Size               => Rep_Aspect,
 767       Aspect_Machine_Radix                => Rep_Aspect,
 768       Aspect_Object_Size                  => Rep_Aspect,
 769       Aspect_Pack                         => Rep_Aspect,
 770       Aspect_Scalar_Storage_Order         => Rep_Aspect,
 771       Aspect_Size                         => Rep_Aspect,
 772       Aspect_Small                        => Rep_Aspect,
 773       Aspect_Storage_Size                 => Rep_Aspect,
 774       Aspect_Value_Size                   => Rep_Aspect,
 775       Aspect_Volatile                     => Rep_Aspect,
 776       Aspect_Volatile_Components          => Rep_Aspect,
 777       Aspect_Volatile_Full_Access         => Rep_Aspect);
 778
 779    ------------------------------------------------
 780    -- Handling of Aspect Specifications on Stubs --
 781    ------------------------------------------------
 782
 783    --  Aspects that appear on the following stub nodes
 784
 785    --    N_Package_Body_Stub
 786    --    N_Protected_Body_Stub
 787    --    N_Subprogram_Body_Stub
 788    --    N_Task_Body_Stub
 789
 790    --  are treated as if they apply to the corresponding proper body. Their
 791    --  analysis is postponed until the analysis of the proper body takes place
 792    --  (see Analyze_Proper_Body). The delay is required because the analysis
 793    --  may generate extra code which would be harder to relocate to the body.
 794    --  If the proper body is present, the aspect specifications are relocated
 795    --  to the corresponding body node:
 796
 797    --    N_Package_Body
 798    --    N_Protected_Body
 799    --    N_Subprogram_Body
 800    --    N_Task_Body
 801
 802    --  The subsequent analysis takes care of the aspect-to-pragma conversions
 803    --  and verification of pragma legality. In the case where the proper body
 804    --  is not available, the aspect specifications are analyzed on the spot
 805    --  (see Analyze_Proper_Body) to catch potential errors.
 806
 807    --  The following table lists all aspects that can apply to a subprogram
 808    --  body [stub]. For instance, the following example is legal:
 809
 810    --    package P with SPARK_Mode ...;
 811    --    package body P with SPARK_Mode is ...;
 812
 813    --  The table should be synchronized with Pragma_On_Body_Or_Stub_OK in unit
 814    --  Sem_Prag.
 815
 816    Aspect_On_Body_Or_Stub_OK : constant array (Aspect_Id) of Boolean :=
 817      (Aspect_Refined_Depends              => True,
 818       Aspect_Refined_Global               => True,
 819       Aspect_Refined_Post                 => True,
 820       Aspect_SPARK_Mode                   => True,
 821       Aspect_Warnings                     => True,
 822       others                              => False);
 823
 824    -------------------------------------------------------------------
 825    -- Handling of Aspects Specifications on Single Concurrent Types --
 826    -------------------------------------------------------------------
 827
 828    --  Certain aspects that appear on the following nodes
 829
 830    --    N_Single_Protected_Declaration
 831    --    N_Single_Task_Declaration
 832
 833    --  are treated as if they apply to the anonymous object produced by the
 834    --  analysis of a single concurrent type. The following table lists all
 835    --  aspects that should apply to the anonymous object. The table should
 836    --  be synchronized with Pragma_On_Anonymous_Object_OK in unit Sem_Prag.
 837
 838    Aspect_On_Anonymous_Object_OK : constant array (Aspect_Id) of Boolean :=
 839      (Aspect_Depends                      => True,
 840       Aspect_Global                       => True,
 841       Aspect_Part_Of                      => True,
 842       others                              => False);
 843
 844    ---------------------------------------------------
 845    -- Handling of Aspect Specifications in the Tree --
 846    ---------------------------------------------------
 847
 848    --  Several kinds of declaration node permit aspect specifications in Ada
 849    --  2012 mode. If there was room in all the corresponding declaration nodes,
 850    --  we could just have a field Aspect_Specifications pointing to a list of
 851    --  nodes for the aspects (N_Aspect_Specification nodes). But there isn't
 852    --  room, so we adopt a different approach.
 853
 854    --  The following subprograms provide access to a specialized interface
 855    --  implemented internally with a hash table in the body, that provides
 856    --  access to aspect specifications.
 857
 858    function Aspect_Specifications (N : Node_Id) return List_Id;
 859    --  Given a node N, returns the list of N_Aspect_Specification nodes that
 860    --  are attached to this declaration node. If the node is in the class of
 861    --  declaration nodes that permit aspect specifications, as defined by the
 862    --  predicate above, and if their Has_Aspects flag is set to True, then this
 863    --  will always be a non-empty list. If this flag is set to False, then
 864    --  No_List is returned. Normally, the only nodes that have Has_Aspects set
 865    --  True are the nodes for which Permits_Aspect_Specifications would return
 866    --  True (i.e. the declaration nodes defined in the RM as permitting the
 867    --  presence of Aspect_Specifications). However, it is possible for the
 868    --  flag Has_Aspects to be set on other nodes as a result of Rewrite and
 869    --  Replace calls, and this function may be used to retrieve the aspect
 870    --  specifications for the original rewritten node in such cases.
 871
 872    function Aspects_On_Body_Or_Stub_OK (N : Node_Id) return Boolean;
 873    --  N denotes a body [stub] with aspects. Determine whether all aspects of N
 874    --  are allowed to appear on a body [stub].
 875
 876    procedure Exchange_Aspects (N1 : Node_Id; N2 : Node_Id);
 877    --  Exchange the aspect specifications of two nodes. If either node lacks an
 878    --  aspect specification list, the routine has no effect. It is assumed that
 879    --  both nodes can support aspects.
 880
 881    function Find_Aspect (Id : Entity_Id; A : Aspect_Id) return Node_Id;
 882    --  Find the aspect specification of aspect A associated with entity I.
 883    --  Return Empty if Id does not have the requested aspect.
 884
 885    function Find_Value_Of_Aspect
 886      (Id : Entity_Id;
 887       A  : Aspect_Id) return Node_Id;
 888    --  Find the value of aspect A associated with entity Id. Return Empty if
 889    --  Id does not have the requested aspect.
 890
 891    function Has_Aspect (Id : Entity_Id; A : Aspect_Id) return Boolean;
 892    --  Determine whether entity Id has aspect A
 893
 894    procedure Move_Aspects (From : Node_Id; To : Node_Id);
 895    --  Relocate the aspect specifications of node From to node To. On entry it
 896    --  is assumed that To does not have aspect specifications. If From has no
 897    --  aspects, the routine has no effect.
 898
 899    procedure Move_Or_Merge_Aspects (From : Node_Id; To : Node_Id);
 900    --  Relocate the aspect specifications of node From to node To. If To has
 901    --  aspects, the aspects of From are appended to the aspects of To. If From
 902    --  has no aspects, the routine has no effect. Special behavior:
 903    --    * When node From denotes a subprogram body stub without a previous
 904    --      declaration, the only aspects relocated to node To are those found
 905    --      in table Aspect_On_Body_Or_Stub_OK.
 906    --    * When node From denotes a single synchronized type declaration, the
 907    --      only aspects relocated to node To are those found in table
 908    --      Aspect_On_Anonymous_Object_OK.
 909
 910    function Permits_Aspect_Specifications (N : Node_Id) return Boolean;
 911    --  Returns True if the node N is a declaration node that permits aspect
 912    --  specifications in the grammar. It is possible for other nodes to have
 913    --  aspect specifications as a result of Rewrite or Replace calls.
 914
 915    procedure Remove_Aspects (N : Node_Id);
 916    --  Delete the aspect specifications associated with node N. If the node has
 917    --  no aspects, the routine has no effect.
 918
 919    function Same_Aspect (A1 : Aspect_Id; A2 : Aspect_Id) return Boolean;
 920    --  Returns True if A1 and A2 are (essentially) the same aspect. This is not
 921    --  a simple equality test because e.g. Post and Postcondition are the same.
 922    --  This is used for detecting duplicate aspects.
 923
 924    procedure Set_Aspect_Specifications (N : Node_Id; L : List_Id);
 925    --  The node N must be in the class of declaration nodes that permit aspect
 926    --  specifications and the Has_Aspects flag must be False on entry. L must
 927    --  be a non-empty list of N_Aspect_Specification nodes. This procedure sets
 928    --  the Has_Aspects flag to True, and makes an entry that can be retrieved
 929    --  by a subsequent Aspect_Specifications call. It is an error to call this
 930    --  procedure with a node that does not permit aspect specifications, or a
 931    --  node that has its Has_Aspects flag set True on entry, or with L being an
 932    --  empty list or No_List.
 933
 934    procedure Tree_Read;
 935    --  Reads contents of Aspect_Specifications hash table from the tree file
 936
 937    procedure Tree_Write;
 938    --  Writes contents of Aspect_Specifications hash table to the tree file
 939
 940 end Aspects;