gcc/ada/aspects.ads

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  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 with Namet;  use Namet;
  38 with Snames; use Snames;
  39 with Types;  use Types;
  40
  41 package Aspects is
  42
  43    --  Type defining recognized aspects
  44
  45    type Aspect_Id is
  46      (No_Aspect,                            -- Dummy entry for no aspect
  47       Aspect_Address,
  48       Aspect_Alignment,
  49       Aspect_Attach_Handler,
  50       Aspect_Bit_Order,
  51       Aspect_Component_Size,
  52       Aspect_Constant_Indexing,
  53       Aspect_CPU,
  54       Aspect_Default_Component_Value,
  55       Aspect_Default_Iterator,
  56       Aspect_Default_Value,
  57       Aspect_Dimension,                     -- GNAT
  58       Aspect_Dimension_System,              -- GNAT
  59       Aspect_Dispatching_Domain,
  60       Aspect_Dynamic_Predicate,
  61       Aspect_External_Tag,
  62       Aspect_Implicit_Dereference,
  63       Aspect_Input,
  64       Aspect_Interrupt_Priority,
  65       Aspect_Invariant,
  66       Aspect_Iterator_Element,
  67       Aspect_Machine_Radix,
  68       Aspect_Object_Size,                   -- GNAT
  69       Aspect_Output,
  70       Aspect_Post,
  71       Aspect_Postcondition,
  72       Aspect_Pre,
  73       Aspect_Precondition,
  74       Aspect_Predicate,                     -- GNAT
  75       Aspect_Priority,
  76       Aspect_Read,
  77       Aspect_Size,
  78       Aspect_Small,
  79       Aspect_Static_Predicate,
  80       Aspect_Storage_Pool,
  81       Aspect_Storage_Size,
  82       Aspect_Stream_Size,
  83       Aspect_Suppress,
  84       Aspect_Test_Case,                     -- GNAT
  85       Aspect_Type_Invariant,
  86       Aspect_Unsuppress,
  87       Aspect_Value_Size,                    -- GNAT
  88       Aspect_Variable_Indexing,
  89       Aspect_Warnings,
  90       Aspect_Write,
  91
  92       --  The following aspects correspond to library unit pragmas
  93
  94       Aspect_All_Calls_Remote,
  95       Aspect_Compiler_Unit,                 -- GNAT
  96       Aspect_Elaborate_Body,
  97       Aspect_Preelaborate,
  98       Aspect_Preelaborate_05,               -- GNAT
  99       Aspect_Pure,
 100       Aspect_Pure_05,                       -- GNAT
 101       Aspect_Pure_12,                       -- GNAT
 102       Aspect_Remote_Call_Interface,
 103       Aspect_Remote_Types,
 104       Aspect_Shared_Passive,
 105       Aspect_Universal_Data,                -- GNAT
 106
 107       --  Remaining aspects have a static boolean value that turns the aspect
 108       --  on or off. They all correspond to pragmas, but are only converted to
 109       --  the pragmas where the value is True. A value of False normally means
 110       --  that the aspect is ignored, except in the case of derived types where
 111       --  the aspect value is inherited from the parent, in which case, we do
 112       --  not allow False if we inherit a True value from the parent.
 113
 114       Aspect_Ada_2005,                      -- GNAT
 115       Aspect_Ada_2012,                      -- GNAT
 116       Aspect_Asynchronous,
 117       Aspect_Atomic,
 118       Aspect_Atomic_Components,
 119       Aspect_Discard_Names,
 120       Aspect_Favor_Top_Level,               -- GNAT
 121       Aspect_Independent,
 122       Aspect_Independent_Components,
 123       Aspect_Inline,
 124       Aspect_Inline_Always,                 -- GNAT
 125       Aspect_Interrupt_Handler,
 126       Aspect_No_Return,
 127       Aspect_Pack,
 128       Aspect_Persistent_BSS,                -- GNAT
 129       Aspect_Preelaborable_Initialization,
 130       Aspect_Pure_Function,                 -- GNAT
 131       Aspect_Shared,                        -- GNAT (equivalent to Atomic)
 132       Aspect_Suppress_Debug_Info,           -- GNAT
 133       Aspect_Unchecked_Union,
 134       Aspect_Universal_Aliasing,            -- GNAT
 135       Aspect_Unmodified,                    -- GNAT
 136       Aspect_Unreferenced,                  -- GNAT
 137       Aspect_Unreferenced_Objects,          -- GNAT
 138       Aspect_Volatile,
 139       Aspect_Volatile_Components);
 140
 141    --  The following array indicates aspects that accept 'Class
 142
 143    Class_Aspect_OK : constant array (Aspect_Id) of Boolean :=
 144                        (Aspect_Invariant     => True,
 145                         Aspect_Pre           => True,
 146                         Aspect_Predicate     => True,
 147                         Aspect_Post          => True,
 148                         others               => False);
 149
 150    --  The following array indicates aspects that a subtype inherits from
 151    --  its base type. True means that the subtype inherits the aspect from
 152    --  its base type. False means it is not inherited.
 153
 154    Base_Aspect : constant array (Aspect_Id) of Boolean :=
 155                    (Aspect_Atomic                  => True,
 156                     Aspect_Atomic_Components       => True,
 157                     Aspect_Discard_Names           => True,
 158                     Aspect_Independent_Components  => True,
 159                     Aspect_Iterator_Element        => True,
 160                     Aspect_Constant_Indexing       => True,
 161                     Aspect_Default_Iterator        => True,
 162                     Aspect_Type_Invariant          => True,
 163                     Aspect_Unchecked_Union         => True,
 164                     Aspect_Variable_Indexing       => True,
 165                     Aspect_Volatile                => True,
 166                     others                         => False);
 167
 168    --  The following array identifies all implementation defined aspects
 169
 170    Impl_Defined_Aspects : constant array (Aspect_Id) of Boolean :=
 171                             (Aspect_Ada_2005             => True,
 172                              Aspect_Ada_2012             => True,
 173                              Aspect_Compiler_Unit        => True,
 174                              Aspect_Dimension            => True,
 175                              Aspect_Dimension_System     => True,
 176                              Aspect_Favor_Top_Level      => True,
 177                              Aspect_Inline_Always        => True,
 178                              Aspect_Object_Size          => True,
 179                              Aspect_Persistent_BSS       => True,
 180                              Aspect_Predicate            => True,
 181                              Aspect_Preelaborate_05      => True,
 182                              Aspect_Pure_05              => True,
 183                              Aspect_Pure_12              => True,
 184                              Aspect_Pure_Function        => True,
 185                              Aspect_Shared               => True,
 186                              Aspect_Suppress_Debug_Info  => True,
 187                              Aspect_Test_Case            => True,
 188                              Aspect_Universal_Data       => True,
 189                              Aspect_Universal_Aliasing   => True,
 190                              Aspect_Unmodified           => True,
 191                              Aspect_Unreferenced         => True,
 192                              Aspect_Unreferenced_Objects => True,
 193                              Aspect_Value_Size           => True,
 194                              others                      => False);
 195
 196    --  The following array indicates aspects for which multiple occurrences of
 197    --  the same aspect attached to the same declaration are allowed.
 198
 199    No_Duplicates_Allowed : constant array (Aspect_Id) of Boolean :=
 200                              (Aspect_Test_Case => False,
 201                               others           => True);
 202
 203    --  The following array indicates type aspects that are inherited and apply
 204    --  to the class-wide type as well.
 205
 206    Inherited_Aspect : constant array (Aspect_Id) of Boolean :=
 207                         (Aspect_Constant_Indexing    => True,
 208                          Aspect_Default_Iterator     => True,
 209                          Aspect_Implicit_Dereference => True,
 210                          Aspect_Iterator_Element     => True,
 211                          Aspect_Remote_Types         => True,
 212                          Aspect_Variable_Indexing    => True,
 213                          others                      => False);
 214
 215    --  The following subtype defines aspects corresponding to library unit
 216    --  pragmas, these can only validly appear as aspects for library units,
 217    --  and result in a corresponding pragma being inserted immediately after
 218    --  the occurrence of the aspect.
 219
 220    subtype Library_Unit_Aspects is
 221      Aspect_Id range Aspect_All_Calls_Remote .. Aspect_Universal_Data;
 222
 223    --  The following subtype defines aspects accepting an optional static
 224    --  boolean parameter indicating if the aspect should be active or
 225    --  cancelling. If the parameter is missing the effective value is True,
 226    --  enabling the aspect. If the parameter is present it must be a static
 227    --  expression of type Standard.Boolean. If the value is True, then the
 228    --  aspect is enabled. If it is False, the aspect is disabled.
 229
 230    subtype Boolean_Aspects is
 231      Aspect_Id range Aspect_Ada_2005 .. Aspect_Id'Last;
 232
 233    subtype Pre_Post_Aspects is
 234      Aspect_Id range Aspect_Post .. Aspect_Precondition;
 235
 236    --  The following type is used for indicating allowed expression forms
 237
 238    type Aspect_Expression is
 239      (Optional,               -- Optional boolean expression
 240       Expression,             -- Required expression
 241       Name);                  -- Required name
 242
 243    --  The following array indicates what argument type is required
 244
 245    Aspect_Argument : constant array (Aspect_Id) of Aspect_Expression :=
 246                        (No_Aspect                      => Optional,
 247                         Aspect_Address                 => Expression,
 248                         Aspect_Alignment               => Expression,
 249                         Aspect_Attach_Handler          => Expression,
 250                         Aspect_Bit_Order               => Expression,
 251                         Aspect_Component_Size          => Expression,
 252                         Aspect_Constant_Indexing       => Name,
 253                         Aspect_CPU                     => Expression,
 254                         Aspect_Default_Component_Value => Expression,
 255                         Aspect_Default_Iterator        => Name,
 256                         Aspect_Default_Value           => Expression,
 257                         Aspect_Dimension               => Expression,
 258                         Aspect_Dimension_System        => Expression,
 259                         Aspect_Dispatching_Domain      => Expression,
 260                         Aspect_Dynamic_Predicate       => Expression,
 261                         Aspect_External_Tag            => Expression,
 262                         Aspect_Implicit_Dereference    => Name,
 263                         Aspect_Input                   => Name,
 264                         Aspect_Interrupt_Priority      => Expression,
 265                         Aspect_Invariant               => Expression,
 266                         Aspect_Iterator_Element        => Name,
 267                         Aspect_Machine_Radix           => Expression,
 268                         Aspect_Object_Size             => Expression,
 269                         Aspect_Output                  => Name,
 270                         Aspect_Post                    => Expression,
 271                         Aspect_Postcondition           => Expression,
 272                         Aspect_Pre                     => Expression,
 273                         Aspect_Precondition            => Expression,
 274                         Aspect_Predicate               => Expression,
 275                         Aspect_Priority                => Expression,
 276                         Aspect_Read                    => Name,
 277                         Aspect_Size                    => Expression,
 278                         Aspect_Small                   => Expression,
 279                         Aspect_Static_Predicate        => Expression,
 280                         Aspect_Storage_Pool            => Name,
 281                         Aspect_Storage_Size            => Expression,
 282                         Aspect_Stream_Size             => Expression,
 283                         Aspect_Suppress                => Name,
 284                         Aspect_Test_Case               => Expression,
 285                         Aspect_Type_Invariant          => Expression,
 286                         Aspect_Unsuppress              => Name,
 287                         Aspect_Value_Size              => Expression,
 288                         Aspect_Variable_Indexing       => Name,
 289                         Aspect_Warnings                => Name,
 290                         Aspect_Write                   => Name,
 291
 292                         Library_Unit_Aspects           => Optional,
 293                         Boolean_Aspects                => Optional);
 294
 295    -----------------------------------------
 296    -- Table Linking Names and Aspect_Id's --
 297    -----------------------------------------
 298
 299    --  Table linking aspect names and id's
 300
 301    Aspect_Names : constant array (Aspect_Id) of Name_Id := (
 302      No_Aspect                           => No_Name,
 303      Aspect_Ada_2005                     => Name_Ada_2005,
 304      Aspect_Ada_2012                     => Name_Ada_2012,
 305      Aspect_Address                      => Name_Address,
 306      Aspect_Alignment                    => Name_Alignment,
 307      Aspect_All_Calls_Remote             => Name_All_Calls_Remote,
 308      Aspect_Asynchronous                 => Name_Asynchronous,
 309      Aspect_Atomic                       => Name_Atomic,
 310      Aspect_Atomic_Components            => Name_Atomic_Components,
 311      Aspect_Attach_Handler               => Name_Attach_Handler,
 312      Aspect_Bit_Order                    => Name_Bit_Order,
 313      Aspect_Compiler_Unit                => Name_Compiler_Unit,
 314      Aspect_Component_Size               => Name_Component_Size,
 315      Aspect_Constant_Indexing            => Name_Constant_Indexing,
 316      Aspect_CPU                          => Name_CPU,
 317      Aspect_Default_Iterator             => Name_Default_Iterator,
 318      Aspect_Default_Value                => Name_Default_Value,
 319      Aspect_Default_Component_Value      => Name_Default_Component_Value,
 320      Aspect_Dimension                    => Name_Dimension,
 321      Aspect_Dimension_System             => Name_Dimension_System,
 322      Aspect_Discard_Names                => Name_Discard_Names,
 323      Aspect_Dispatching_Domain           => Name_Dispatching_Domain,
 324      Aspect_Dynamic_Predicate            => Name_Dynamic_Predicate,
 325      Aspect_Elaborate_Body               => Name_Elaborate_Body,
 326      Aspect_External_Tag                 => Name_External_Tag,
 327      Aspect_Favor_Top_Level              => Name_Favor_Top_Level,
 328      Aspect_Implicit_Dereference         => Name_Implicit_Dereference,
 329      Aspect_Independent                  => Name_Independent,
 330      Aspect_Independent_Components       => Name_Independent_Components,
 331      Aspect_Inline                       => Name_Inline,
 332      Aspect_Inline_Always                => Name_Inline_Always,
 333      Aspect_Input                        => Name_Input,
 334      Aspect_Interrupt_Handler            => Name_Interrupt_Handler,
 335      Aspect_Interrupt_Priority           => Name_Interrupt_Priority,
 336      Aspect_Invariant                    => Name_Invariant,
 337      Aspect_Iterator_Element             => Name_Iterator_Element,
 338      Aspect_Machine_Radix                => Name_Machine_Radix,
 339      Aspect_No_Return                    => Name_No_Return,
 340      Aspect_Object_Size                  => Name_Object_Size,
 341      Aspect_Output                       => Name_Output,
 342      Aspect_Pack                         => Name_Pack,
 343      Aspect_Persistent_BSS               => Name_Persistent_BSS,
 344      Aspect_Post                         => Name_Post,
 345      Aspect_Postcondition                => Name_Postcondition,
 346      Aspect_Pre                          => Name_Pre,
 347      Aspect_Precondition                 => Name_Precondition,
 348      Aspect_Predicate                    => Name_Predicate,
 349      Aspect_Preelaborable_Initialization => Name_Preelaborable_Initialization,
 350      Aspect_Preelaborate                 => Name_Preelaborate,
 351      Aspect_Preelaborate_05              => Name_Preelaborate_05,
 352      Aspect_Priority                     => Name_Priority,
 353      Aspect_Pure                         => Name_Pure,
 354      Aspect_Pure_05                      => Name_Pure_05,
 355      Aspect_Pure_12                      => Name_Pure_12,
 356      Aspect_Pure_Function                => Name_Pure_Function,
 357      Aspect_Read                         => Name_Read,
 358      Aspect_Remote_Call_Interface        => Name_Remote_Call_Interface,
 359      Aspect_Remote_Types                 => Name_Remote_Types,
 360      Aspect_Shared                       => Name_Shared,
 361      Aspect_Shared_Passive               => Name_Shared_Passive,
 362      Aspect_Size                         => Name_Size,
 363      Aspect_Small                        => Name_Small,
 364      Aspect_Static_Predicate             => Name_Static_Predicate,
 365      Aspect_Storage_Pool                 => Name_Storage_Pool,
 366      Aspect_Storage_Size                 => Name_Storage_Size,
 367      Aspect_Stream_Size                  => Name_Stream_Size,
 368      Aspect_Suppress                     => Name_Suppress,
 369      Aspect_Suppress_Debug_Info          => Name_Suppress_Debug_Info,
 370      Aspect_Test_Case                    => Name_Test_Case,
 371      Aspect_Type_Invariant               => Name_Type_Invariant,
 372      Aspect_Unchecked_Union              => Name_Unchecked_Union,
 373      Aspect_Universal_Aliasing           => Name_Universal_Aliasing,
 374      Aspect_Universal_Data               => Name_Universal_Data,
 375      Aspect_Unmodified                   => Name_Unmodified,
 376      Aspect_Unreferenced                 => Name_Unreferenced,
 377      Aspect_Unreferenced_Objects         => Name_Unreferenced_Objects,
 378      Aspect_Unsuppress                   => Name_Unsuppress,
 379      Aspect_Value_Size                   => Name_Value_Size,
 380      Aspect_Variable_Indexing            => Name_Variable_Indexing,
 381      Aspect_Volatile                     => Name_Volatile,
 382      Aspect_Volatile_Components          => Name_Volatile_Components,
 383      Aspect_Warnings                     => Name_Warnings,
 384      Aspect_Write                        => Name_Write);
 385
 386    function Get_Aspect_Id (Name : Name_Id) return Aspect_Id;
 387    pragma Inline (Get_Aspect_Id);
 388    --  Given a name Nam, returns the corresponding aspect id value. If the name
 389    --  does not match any aspect, then No_Aspect is returned as the result.
 390
 391    ---------------------------------------------------
 392    -- Handling of Aspect Specifications in the Tree --
 393    ---------------------------------------------------
 394
 395    --  Several kinds of declaration node permit aspect specifications in Ada
 396    --  2012 mode. If there was room in all the corresponding declaration nodes,
 397    --  we could just have a field Aspect_Specifications pointing to a list of
 398    --  nodes for the aspects (N_Aspect_Specification nodes). But there isn't
 399    --  room, so we adopt a different approach.
 400
 401    --  The following subprograms provide access to a specialized interface
 402    --  implemented internally with a hash table in the body, that provides
 403    --  access to aspect specifications.
 404
 405    function Permits_Aspect_Specifications (N : Node_Id) return Boolean;
 406    --  Returns True if the node N is a declaration node that permits aspect
 407    --  specifications in the grammar. It is possible for other nodes to have
 408    --  aspect specifications as a result of Rewrite or Replace calls.
 409
 410    function Aspect_Specifications (N : Node_Id) return List_Id;
 411    --  Given a node N, returns the list of N_Aspect_Specification nodes that
 412    --  are attached to this declaration node. If the node is in the class of
 413    --  declaration nodes that permit aspect specifications, as defined by the
 414    --  predicate above, and if their Has_Aspects flag is set to True, then this
 415    --  will always be a non-empty list. If this flag is set to False, then
 416    --  No_List is returned. Normally, the only nodes that have Has_Aspects set
 417    --  True are the nodes for which Permits_Aspect_Specifications would return
 418    --  True (i.e. the declaration nodes defined in the RM as permitting the
 419    --  presence of Aspect_Specifications). However, it is possible for the
 420    --  flag Has_Aspects to be set on other nodes as a result of Rewrite and
 421    --  Replace calls, and this function may be used to retrieve the aspect
 422    --  specifications for the original rewritten node in such cases.
 423
 424    procedure Set_Aspect_Specifications (N : Node_Id; L : List_Id);
 425    --  The node N must be in the class of declaration nodes that permit aspect
 426    --  specifications and the Has_Aspects flag must be False on entry. L must
 427    --  be a non-empty list of N_Aspect_Specification nodes. This procedure sets
 428    --  the Has_Aspects flag to True, and makes an entry that can be retrieved
 429    --  by a subsequent Aspect_Specifications call. It is an error to call this
 430    --  procedure with a node that does not permit aspect specifications, or a
 431    --  node that has its Has_Aspects flag set True on entry, or with L being an
 432    --  empty list or No_List.
 433
 434    function Find_Aspect (Ent : Entity_Id; A : Aspect_Id) return Node_Id;
 435    --  Find value of a given aspect from aspect list of entity
 436
 437    procedure Move_Aspects (From : Node_Id; To : Node_Id);
 438    --  Moves aspects from 'From' node to 'To' node. Has_Aspects (To) must be
 439    --  False on entry. If Has_Aspects (From) is False, the call has no effect.
 440    --  Otherwise the aspects are moved and on return Has_Aspects (To) is True,
 441    --  and Has_Aspects (From) is False.
 442
 443    function Same_Aspect (A1 : Aspect_Id; A2 : Aspect_Id) return Boolean;
 444    --  Returns True if A1 and A2 are (essentially) the same aspect. This is not
 445    --  a simple equality test because e.g. Post and Postcondition are the same.
 446    --  This is used for detecting duplicate aspects.
 447
 448    procedure Tree_Write;
 449    --  Writes contents of Aspect_Specifications hash table to the tree file
 450
 451    procedure Tree_Read;
 452    --  Reads contents of Aspect_Specifications hash table from the tree file
 453
 454 end Aspects;