gcc/ada/sem_aux.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              S E M _ A U X                               --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2023, 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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  Package containing utility procedures used throughout the compiler.
  27
  28 --  Historical note. Many of the routines here were originally in Einfo, but
  29 --  Einfo is supposed to be a relatively low level package dealing with the
  30 --  content of entities in the tree, so this package is used for routines that
  31 --  require more than minimal semantic knowledge.
  32
  33 with Alloc;
  34 with Namet; use Namet;
  35 with Table;
  36 with Types; use Types;
  37
  38 package Sem_Aux is
  39
  40    --------------------------------
  41    -- Obsolescent Warnings Table --
  42    --------------------------------
  43
  44    --  This table records entities for which a pragma Obsolescent with a
  45    --  message argument has been processed.
  46
  47    type OWT_Record is record
  48       Ent : Entity_Id;
  49       --  The entity to which the pragma applies
  50
  51       Msg : String_Id;
  52       --  The string containing the message
  53    end record;
  54
  55    package Obsolescent_Warnings is new Table.Table (
  56      Table_Component_Type => OWT_Record,
  57      Table_Index_Type     => Int,
  58      Table_Low_Bound      => 0,
  59      Table_Initial        => Alloc.Obsolescent_Warnings_Initial,
  60      Table_Increment      => Alloc.Obsolescent_Warnings_Increment,
  61      Table_Name           => "Obsolescent_Warnings");
  62
  63    procedure Initialize;
  64    --  Called at the start of compilation of each new main source file to
  65    --  initialize the allocation of the Obsolescent_Warnings table.
  66
  67    -----------------
  68    -- Subprograms --
  69    -----------------
  70
  71    function Ancestor_Subtype (Typ : Entity_Id) return Entity_Id;
  72    --  The argument Typ is a type or subtype entity. If the argument is a
  73    --  subtype then it returns the subtype or type from which the subtype was
  74    --  obtained, otherwise it returns Empty.
  75
  76    --  WARNING: There is a matching C declaration of this subprogram in fe.h
  77
  78    function Available_View (Ent : Entity_Id) return Entity_Id;
  79    --  Ent denotes an abstract state or a type that may come from a limited
  80    --  with clause. Return the non-limited view of Ent if there is one or Ent
  81    --  if this is not the case.
  82
  83    function Constant_Value (Ent : Entity_Id) return Node_Id;
  84    --  Ent is a variable, constant, named integer, or named real entity. This
  85    --  call obtains the initialization expression for the entity. Will return
  86    --  Empty for a deferred constant whose full view is not available or
  87    --  in some other cases of internal entities, which cannot be treated as
  88    --  constants from the point of view of constant folding. Empty is also
  89    --  returned for variables with no initialization expression.
  90
  91    --  WARNING: There is a matching C declaration of this subprogram in fe.h
  92
  93    function Corresponding_Unsigned_Type (Typ : Entity_Id) return Entity_Id;
  94    --  Typ is a signed integer subtype. This routine returns the standard
  95    --  unsigned type with the same Esize as the implementation base type of
  96    --  Typ, e.g. Long_Integer => Long_Unsigned.
  97
  98    function Enclosing_Dynamic_Scope (Ent : Entity_Id) return Entity_Id;
  99    --  For any entity, Ent, returns the closest dynamic scope in which the
 100    --  entity is declared or Standard_Standard for library-level entities.
 101
 102    function First_Discriminant (Typ : Entity_Id) return Entity_Id;
 103    --  Typ is a type with discriminants. The discriminants are the first
 104    --  entities declared in the type, so normally this is equivalent to
 105    --  First_Entity. The exception arises for tagged types, where the tag
 106    --  itself is prepended to the front of the entity chain, so the
 107    --  First_Discriminant function steps past the tag if it is present.
 108    --  The caller is responsible for checking that the type has discriminants.
 109    --  When called on a private type with unknown discriminants, the function
 110    --  always returns Empty.
 111
 112    --  WARNING: There is a matching C declaration of this subprogram in fe.h
 113
 114    function First_Stored_Discriminant (Typ : Entity_Id) return Entity_Id;
 115    --  Typ is a type with discriminants. Gives the first discriminant stored
 116    --  in an object of this type. In many cases, these are the same as the
 117    --  normal visible discriminants for the type, but in the case of renamed
 118    --  discriminants, this is not always the case.
 119    --
 120    --  For tagged types, and untagged types which are root types or derived
 121    --  types but which do not rename discriminants in their root type, the
 122    --  stored discriminants are the same as the actual discriminants of the
 123    --  type, and hence this function is the same as First_Discriminant.
 124    --
 125    --  For derived untagged types that rename discriminants in the root type
 126    --  this is the first of the discriminants that occur in the root type. To
 127    --  be precise, in this case stored discriminants are entities attached to
 128    --  the entity chain of the derived type which are a copy of the
 129    --  discriminants of the root type. Furthermore their Is_Completely_Hidden
 130    --  flag is set since although they are actually stored in the object, they
 131    --  are not in the set of discriminants that is visible in the type.
 132    --
 133    --  For derived untagged types, the set of stored discriminants are the real
 134    --  discriminants from Gigi's standpoint, i.e. those that will be stored in
 135    --  actual objects of the type.
 136
 137    --  WARNING: There is a matching C declaration of this subprogram in fe.h
 138
 139    function First_Subtype (Typ : Entity_Id) return Entity_Id;
 140    --  Applies to all types and subtypes. For types, yields the first subtype
 141    --  of the type. For subtypes, yields the first subtype of the base type of
 142    --  the subtype.
 143
 144    --  WARNING: There is a matching C declaration of this subprogram in fe.h
 145
 146    function First_Tag_Component (Typ : Entity_Id) return Entity_Id;
 147    --  Typ must be a tagged record type. This function returns the Entity for
 148    --  the first _Tag field in the record type.
 149
 150    function Get_Called_Entity (Call : Node_Id) return Entity_Id;
 151    --  Obtain the entity of the entry, operator, or subprogram being invoked
 152    --  by call Call.
 153
 154    function Get_Rep_Item
 155      (E             : Entity_Id;
 156       Nam           : Name_Id;
 157       Check_Parents : Boolean := True) return Node_Id;
 158    --  Searches the Rep_Item chain for a given entity E, for an instance of a
 159    --  rep item (pragma, attribute definition clause, or aspect specification)
 160    --  whose name matches the given name Nam. If Check_Parents is False then it
 161    --  only returns rep item that has been directly specified for E (and not
 162    --  inherited from its parents, if any). If one is found, it is returned,
 163    --  otherwise Empty is returned. A special case is that when Nam is
 164    --  Name_Priority, the call will also find Interrupt_Priority.
 165
 166    function Get_Rep_Item
 167      (E             : Entity_Id;
 168       Nam1          : Name_Id;
 169       Nam2          : Name_Id;
 170       Check_Parents : Boolean := True) return Node_Id;
 171    --  Searches the Rep_Item chain for a given entity E, for an instance of a
 172    --  rep item (pragma, attribute definition clause, or aspect specification)
 173    --  whose name matches one of the given names Nam1 or Nam2. If Check_Parents
 174    --  is False then it only returns rep item that has been directly specified
 175    --  for E (and not inherited from its parents, if any). If one is found, it
 176    --  is returned, otherwise Empty is returned. A special case is that when
 177    --  one of the given names is Name_Priority, the call will also find
 178    --  Interrupt_Priority.
 179
 180    function Get_Rep_Pragma
 181      (E             : Entity_Id;
 182       Nam           : Name_Id;
 183       Check_Parents : Boolean := True) return Node_Id;
 184    --  Searches the Rep_Item chain for a given entity E, for an instance of a
 185    --  representation pragma whose name matches the given name Nam. If
 186    --  Check_Parents is False then it only returns representation pragma that
 187    --  has been directly specified for E (and not inherited from its parents,
 188    --  if any). If one is found and if it is the first rep item in the list
 189    --  that matches Nam, it is returned, otherwise Empty is returned. A special
 190    --  case is that when Nam is Name_Priority, the call will also find
 191    --  Interrupt_Priority.
 192
 193    function Get_Rep_Pragma
 194      (E             : Entity_Id;
 195       Nam1          : Name_Id;
 196       Nam2          : Name_Id;
 197       Check_Parents : Boolean := True) return Node_Id;
 198    --  Searches the Rep_Item chain for a given entity E, for an instance of a
 199    --  representation pragma whose name matches one of the given names Nam1 or
 200    --  Nam2. If Check_Parents is False then it only returns representation
 201    --  pragma that has been directly specified for E (and not inherited from
 202    --  its parents, if any). If one is found and if it is the first rep item in
 203    --  the list that matches one of the given names, it is returned, otherwise
 204    --  Empty is returned. A special case is that when one of the given names is
 205    --  Name_Priority, the call will also find Interrupt_Priority.
 206
 207    function Has_Rep_Item
 208      (E             : Entity_Id;
 209       Nam           : Name_Id;
 210       Check_Parents : Boolean := True) return Boolean;
 211    --  Searches the Rep_Item chain for the given entity E, for an instance of a
 212    --  rep item (pragma, attribute definition clause, or aspect specification)
 213    --  with the given name Nam. If Check_Parents is False then it only checks
 214    --  for a rep item that has been directly specified for E (and not inherited
 215    --  from its parents, if any). If found then True is returned, otherwise
 216    --  False indicates that no matching entry was found.
 217
 218    function Has_Rep_Item
 219      (E             : Entity_Id;
 220       Nam1          : Name_Id;
 221       Nam2          : Name_Id;
 222       Check_Parents : Boolean := True) return Boolean;
 223    --  Searches the Rep_Item chain for the given entity E, for an instance of a
 224    --  rep item (pragma, attribute definition clause, or aspect specification)
 225    --  with the given names Nam1 or Nam2. If Check_Parents is False then it
 226    --  only checks for a rep item that has been directly specified for E (and
 227    --  not inherited from its parents, if any). If found then True is returned,
 228    --  otherwise False indicates that no matching entry was found.
 229
 230    function Has_Rep_Pragma
 231      (E             : Entity_Id;
 232       Nam           : Name_Id;
 233       Check_Parents : Boolean := True) return Boolean;
 234    --  Searches the Rep_Item chain for the given entity E, for an instance of a
 235    --  representation pragma with the given name Nam. If Check_Parents is False
 236    --  then it only checks for a representation pragma that has been directly
 237    --  specified for E (and not inherited from its parents, if any). If found
 238    --  and if it is the first rep item in the list that matches Nam then True
 239    --  is returned, otherwise False indicates that no matching entry was found.
 240
 241    function Has_Rep_Pragma
 242      (E             : Entity_Id;
 243       Nam1          : Name_Id;
 244       Nam2          : Name_Id;
 245       Check_Parents : Boolean := True) return Boolean;
 246    --  Searches the Rep_Item chain for the given entity E, for an instance of a
 247    --  representation pragma with the given names Nam1 or Nam2. If
 248    --  Check_Parents is False then it only checks for a rep item that has been
 249    --  directly specified for E (and not inherited from its parents, if any).
 250    --  If found and if it is the first rep item in the list that matches one of
 251    --  the given names then True is returned, otherwise False indicates that no
 252    --  matching entry was found.
 253
 254    function Has_External_Tag_Rep_Clause (T : Entity_Id) return Boolean;
 255    --  Defined in tagged types. Set if an External_Tag rep. clause has been
 256    --  given for this type. Use to avoid the generation of the default
 257    --  External_Tag.
 258    --
 259    --  Note: we used to use an entity flag for this purpose, but that was wrong
 260    --  because it was not propagated from the private view to the full view. We
 261    --  could have added that propagation, but it would have been an annoying
 262    --  irregularity compared to other representation aspects, and the cost of
 263    --  looking up the aspect when needed is small.
 264
 265    function Has_Unconstrained_Elements (T : Entity_Id) return Boolean;
 266    --  True if T has discriminants and is unconstrained, or is an array type
 267    --  whose element type Has_Unconstrained_Elements.
 268
 269    function Has_Variant_Part (Typ : Entity_Id) return Boolean;
 270    --  Return True if the first subtype of Typ is a discriminated record type
 271    --  which has a variant part. False otherwise.
 272
 273    function In_Generic_Body (Id : Entity_Id) return Boolean;
 274    --  Determine whether entity Id appears inside a generic body
 275
 276    function Initialization_Suppressed (Typ : Entity_Id) return Boolean;
 277    pragma Inline (Initialization_Suppressed);
 278    --  Returns True if initialization should be suppressed for the given type
 279    --  or subtype. This is true if Suppress_Initialization is set either for
 280    --  the subtype itself, or for the corresponding base type.
 281
 282    function Is_Body (N : Node_Id) return Boolean with Inline;
 283    --  Determine whether an arbitrary node denotes a body
 284
 285    function Is_By_Copy_Type (Ent : Entity_Id) return Boolean;
 286    --  Ent is any entity. Returns True if Ent is a type entity where the type
 287    --  is required to be passed by copy, as defined in (RM 6.2(3)).
 288
 289    function Is_By_Reference_Type (Ent : Entity_Id) return Boolean;
 290    --  Ent is any entity. Returns True if Ent is a type entity where the type
 291    --  is required to be passed by reference, as defined in (RM 6.2(4-9)).
 292
 293    --  WARNING: There is a matching C declaration of this subprogram in fe.h
 294
 295    function Is_Definite_Subtype (T : Entity_Id) return Boolean;
 296    --  T is a type entity. Returns True if T is a definite subtype.
 297    --  Indefinite subtypes are unconstrained arrays, unconstrained
 298    --  discriminated types without defaulted discriminants, class-wide types,
 299    --  and types with unknown discriminants. Definite subtypes are all others
 300    --  (elementary, constrained composites (including the case of records
 301    --  without discriminants), and types with defaulted discriminants).
 302
 303    function Is_Derived_Type (Ent : Entity_Id) return Boolean;
 304    --  Determines if the given entity Ent is a derived type. Result is always
 305    --  false if argument is not a type.
 306
 307    --  WARNING: There is a matching C declaration of this subprogram in fe.h
 308
 309    function Is_Generic_Formal (E : Entity_Id) return Boolean;
 310    --  Determine whether E is a generic formal parameter. In particular this is
 311    --  used to set the visibility of generic formals of a generic package
 312    --  declared with a box or with partial parameterization.
 313
 314    function Is_Limited_Type (Ent : Entity_Id) return Boolean;
 315    --  Ent is any entity. Returns true if Ent is a limited type (limited
 316    --  private type, limited interface type, task type, protected type,
 317    --  composite containing a limited component, or a subtype of any of
 318    --  these types). This older routine overlaps with the next ones, this
 319    --  should be cleaned up???
 320
 321    function Is_Immutably_Limited_Type (Ent : Entity_Id) return Boolean;
 322    --  Implements definition in Ada 2012 RM-7.5 (8.1/3). This differs from the
 323    --  following predicate in that an untagged record with immutably limited
 324    --  components is NOT by itself immutably limited. This matters, e.g. when
 325    --  checking the legality of an access to the current instance.
 326
 327    function Is_Inherently_Limited_Type (Ent : Entity_Id) return Boolean;
 328    --  Ent is any entity. True for a type that is "inherently" limited (i.e.
 329    --  cannot become nonlimited). From the Ada 2005 RM-7.5(8.1/2), "a type with
 330    --  a part that is of a task, protected, or explicitly limited record type".
 331    --  These are the types that are defined as return-by-reference types in Ada
 332    --  95 (see RM95-6.5(11-16)). In Ada 2005, these are the types that require
 333    --  build-in-place for function calls. Note that build-in-place is allowed
 334    --  for other types, too. This is also used for identifying pure procedures
 335    --  whose calls should not be eliminated (RM 10.2.1(18/2)).
 336
 337    function Nearest_Ancestor (Typ : Entity_Id) return Entity_Id;
 338    --  Given a subtype Typ, this function finds out the nearest ancestor from
 339    --  which constraints and predicates are inherited. There is no simple link
 340    --  for doing this, consider:
 341    --
 342    --     subtype R is Integer range 1 .. 10;
 343    --     type T is new R;
 344    --
 345    --  In this case the nearest ancestor is R, but the Etype of T'Base will
 346    --  point to R'Base, so we have to go rummaging in the declarations to get
 347    --  this information. It is used for making sure we freeze this before we
 348    --  freeze Typ, and also for retrieving inherited predicate information.
 349    --  For the case of base types or first subtypes, there is no useful entity
 350    --  to return, so Empty is returned.
 351    --
 352    --  Note: this is similar to Ancestor_Subtype except that it also deals
 353    --  with the case of derived types.
 354
 355    function Nearest_Dynamic_Scope (Ent : Entity_Id) return Entity_Id;
 356    --  This is similar to Enclosing_Dynamic_Scope except that if Ent is itself
 357    --  a dynamic scope, then it is returned. Otherwise the result is the same
 358    --  as that returned by Enclosing_Dynamic_Scope.
 359
 360    function Next_Tag_Component (Tag : Entity_Id) return Entity_Id;
 361    --  Tag must be an entity representing a _Tag field of a tagged record.
 362    --  The result returned is the next _Tag field in this record, or Empty
 363    --  if this is the last such field.
 364
 365    function Number_Discriminants (Typ : Entity_Id) return Pos;
 366    --  Typ is a type with discriminants, yields number of discriminants in type
 367
 368    function Object_Type_Has_Constrained_Partial_View
 369      (Typ  : Entity_Id;
 370       Scop : Entity_Id) return Boolean;
 371    --  Return True if type of object has attribute Has_Constrained_Partial_View
 372    --  set to True; in addition, within a generic body, return True if subtype
 373    --  of the object is a descendant of an untagged generic formal private or
 374    --  derived type, and the subtype is not an unconstrained array subtype
 375    --  (RM 3.3(23.10/3)).
 376
 377    function Package_Body (E : Entity_Id) return Node_Id;
 378    --  Given an entity for a package, return the corresponding package body, if
 379    --  any, or else Empty.
 380
 381    function Package_Spec (E : Entity_Id) return Node_Id;
 382    --  Given an entity for a package spec, return the corresponding package
 383    --  spec if any, or else Empty.
 384
 385    function Package_Specification (E : Entity_Id) return Node_Id;
 386    --  Given an entity for a package, return the corresponding package
 387    --  specification.
 388
 389    function Subprogram_Body (E : Entity_Id) return Node_Id;
 390    --  Given an entity for a subprogram (spec or body), return the
 391    --  corresponding subprogram body if any, or else Empty.
 392
 393    function Subprogram_Body_Entity (E : Entity_Id) return Entity_Id;
 394    --  Given an entity for a subprogram (spec or body), return the entity
 395    --  corresponding to the subprogram body, which may be the same as E or
 396    --  Empty if no body is available.
 397
 398    function Subprogram_Spec (E : Entity_Id) return Node_Id;
 399    --  Given an entity for a subprogram spec, return the corresponding
 400    --  subprogram spec if any, or else Empty.
 401
 402    function Subprogram_Specification (E : Entity_Id) return Node_Id;
 403    --  Given an entity for a subprogram, return the corresponding subprogram
 404    --  specification. If the entity is an inherited subprogram without
 405    --  specification itself, return the specification of the inherited
 406    --  subprogram.
 407
 408    function Ultimate_Alias (Prim : Entity_Id) return Entity_Id;
 409    pragma Inline (Ultimate_Alias);
 410    --  Return the last entity in the chain of aliased entities of Prim. If Prim
 411    --  has no alias return Prim.
 412
 413    function Unit_Declaration_Node (Unit_Id : Entity_Id) return Node_Id;
 414    --  Unit_Id is the simple name of a program unit, this function returns the
 415    --  corresponding xxx_Declaration node for the entity. Also applies to the
 416    --  body entities for subprograms, tasks and protected units, in which case
 417    --  it returns the subprogram, task or protected body node for it. The unit
 418    --  may be a child unit with any number of ancestors.
 419
 420 end Sem_Aux;