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