gcc/ada/sem_ch3.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              S E M _ C H 3                               --
   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 with Types;  use Types;
  27
  28 package Sem_Ch3 is
  29    procedure Analyze_Component_Declaration         (N : Node_Id);
  30    procedure Analyze_Full_Type_Declaration         (N : Node_Id);
  31    procedure Analyze_Incomplete_Type_Decl          (N : Node_Id);
  32    procedure Analyze_Itype_Reference               (N : Node_Id);
  33    procedure Analyze_Number_Declaration            (N : Node_Id);
  34    procedure Analyze_Object_Declaration            (N : Node_Id);
  35    procedure Analyze_Others_Choice                 (N : Node_Id);
  36    procedure Analyze_Private_Extension_Declaration (N : Node_Id);
  37    procedure Analyze_Subtype_Indication            (N : Node_Id);
  38    procedure Analyze_Variant_Part                  (N : Node_Id);
  39
  40    procedure Analyze_Subtype_Declaration
  41      (N    : Node_Id;
  42       Skip : Boolean := False);
  43    --  Called to analyze a subtype declaration. The parameter Skip is used for
  44    --  Ada 2005 (AI-412). We set to True in order to avoid reentering the
  45    --  defining identifier of N when analyzing a rewritten incomplete subtype
  46    --  declaration.
  47
  48    function Access_Definition
  49      (Related_Nod : Node_Id;
  50       N           : Node_Id) return Entity_Id;
  51    --  An access definition defines a general access type for a formal
  52    --  parameter. The procedure is called when processing formals, when the
  53    --  current scope is the subprogram. The Implicit type is attached to the
  54    --  Related_Nod put into the enclosing scope, so that the only entities
  55    --  defined in the spec are the formals themselves.
  56
  57    procedure Access_Subprogram_Declaration
  58      (T_Name : Entity_Id;
  59       T_Def  : Node_Id);
  60    --  The subprogram specification yields the signature of an implicit
  61    --  type, whose Ekind is Access_Subprogram_Type. This implicit type is the
  62    --  designated type of the declared access type. In subprogram calls, the
  63    --  signature of the implicit type works like the profile of a regular
  64    --  subprogram.
  65
  66    procedure Add_Internal_Interface_Entities (Tagged_Type : Entity_Id);
  67    --  Add to the list of primitives of Tagged_Type the internal entities
  68    --  associated with covered interface primitives. These entities link the
  69    --  interface primitives with the tagged type primitives that cover them.
  70
  71    procedure Analyze_Declarations (L : List_Id);
  72    --  Called to analyze a list of declarations. Also performs necessary
  73    --  freezing actions (such as freezing remaining unfrozen entities at
  74    --  the end of declarative parts), resolves usage names in aspects, and
  75    --  analyzes contracts that require delay until after freezing is done.
  76
  77    procedure Analyze_Interface_Declaration (T : Entity_Id; Def : Node_Id);
  78    --  Analyze an interface declaration or a formal interface declaration
  79
  80    procedure Array_Type_Declaration (T : in out Entity_Id; Def : Node_Id);
  81    --  Process an array type declaration. If the array is constrained, we
  82    --  create an implicit parent array type, with the same index types and
  83    --  component type.
  84
  85    procedure Access_Type_Declaration (T : Entity_Id; Def : Node_Id);
  86    --  Process an access type declaration
  87
  88    procedure Build_Itype_Reference (Ityp : Entity_Id; Nod : Node_Id);
  89    --  Create a reference to an internal type, for use by Gigi. The back-end
  90    --  elaborates itypes on demand, i.e. when their first use is seen. This can
  91    --  lead to scope anomalies if the first use is within a scope that is
  92    --  nested within the scope that contains the point of definition of the
  93    --  itype. The Itype_Reference node forces the elaboration of the itype
  94    --  in the proper scope. The node is inserted after Nod, which is the
  95    --  enclosing declaration that generated Ityp.
  96    --
  97    --  A related mechanism is used during expansion, for itypes created in
  98    --  branches of conditionals. See Ensure_Defined in exp_util. Could both
  99    --  mechanisms be merged ???
 100
 101    procedure Check_Abstract_Overriding (T : Entity_Id);
 102    --  Check that all abstract subprograms inherited from T's parent type have
 103    --  been overridden as required, and that nonabstract subprograms have not
 104    --  been incorrectly overridden with an abstract subprogram.
 105
 106    procedure Check_Aliased_Component_Types (T : Entity_Id);
 107    --  Given an array type or record type T, check that if the type is
 108    --  nonlimited, then the nominal subtype of any components of T that
 109    --  have discriminants must be constrained.
 110
 111    procedure Check_Completion (Body_Id : Node_Id := Empty);
 112    --  At the end of a declarative part, verify that all entities that require
 113    --  completion have received one. If Body_Id is absent, the error indicating
 114    --  a missing completion is placed on the declaration that needs completion.
 115    --  If Body_Id is present, it is the defining identifier of a package body,
 116    --  and errors are posted on that node, rather than on the declarations that
 117    --  require completion in the package declaration.
 118
 119    procedure Check_CPP_Type_Has_No_Defaults (T : Entity_Id);
 120    --  Check that components of imported CPP type T do not have default
 121    --  expressions because the constructor (if any) is on the C++ side.
 122
 123    procedure Derive_Subprogram
 124      (New_Subp     : out Entity_Id;
 125       Parent_Subp  : Entity_Id;
 126       Derived_Type : Entity_Id;
 127       Parent_Type  : Entity_Id;
 128       Actual_Subp  : Entity_Id := Empty);
 129    --  Derive the subprogram Parent_Subp from Parent_Type, and replace the
 130    --  subsidiary subtypes with the derived type to build the specification of
 131    --  the inherited subprogram (returned in New_Subp). For tagged types, the
 132    --  derived subprogram is aliased to that of the actual (in the case where
 133    --  Actual_Subp is nonempty) rather than to the corresponding subprogram of
 134    --  the parent type.
 135
 136    procedure Derive_Subprograms
 137      (Parent_Type    : Entity_Id;
 138       Derived_Type   : Entity_Id;
 139       Generic_Actual : Entity_Id := Empty);
 140    --  To complete type derivation, collect/retrieve the primitive operations
 141    --  of the parent type, and replace the subsidiary subtypes with the derived
 142    --  type, to build the specs of the inherited ops. For generic actuals, the
 143    --  mapping of the primitive operations to those of the parent type is also
 144    --  done by rederiving the operations within the instance. For tagged types,
 145    --  the derived subprograms are aliased to those of the actual, not those of
 146    --  the ancestor.
 147    --
 148    --  Note: one might expect this to be private to the package body, but there
 149    --  is one rather unusual usage in package Exp_Dist.
 150
 151    function Find_Hidden_Interface
 152      (Src  : Elist_Id;
 153       Dest : Elist_Id) return Entity_Id;
 154    --  Ada 2005: Determine whether the interfaces in list Src are all present
 155    --  in the list Dest. Return the first differing interface, or Empty
 156    --  otherwise.
 157
 158    function Find_Type_Of_Subtype_Indic (S : Node_Id) return Entity_Id;
 159    --  Given a subtype indication S (which is really an N_Subtype_Indication
 160    --  node or a plain N_Identifier), find the type of the subtype mark.
 161
 162    function Find_Type_Name (N : Node_Id) return Entity_Id;
 163    --  Enter the identifier in a type definition, or find the entity already
 164    --  declared, in the case of the full declaration of an incomplete or
 165    --  private type. If the previous declaration is tagged then the class-wide
 166    --  entity is propagated to the identifier to prevent multiple incompatible
 167    --  class-wide types that may be created for self-referential anonymous
 168    --  access components.
 169
 170    function Get_Discriminant_Value
 171      (Discriminant       : Entity_Id;
 172       Typ_For_Constraint : Entity_Id;
 173       Constraint         : Elist_Id) return Node_Id;
 174    --  Given a discriminant Discriminant occurring somewhere up the derivation
 175    --  tree from Typ_For_Constraint and a Constraint, return the expression
 176    --  corresponding to that discriminant in the constraint that specifies its
 177    --  value.
 178
 179    function Is_Visible_Component
 180      (C : Entity_Id;
 181       N : Node_Id := Empty) return Boolean;
 182    --  Determines if a record component C is visible in the present context.
 183    --  Note that even though component C could appear in the entity chain of a
 184    --  record type, C may not be visible in the current context. For instance,
 185    --  C may be a component inherited in the full view of a private extension
 186    --  which is not visible in the current context.
 187    --
 188    --  If present, N is the selected component of which C is the selector. If
 189    --  the prefix of N is a type conversion inserted for a discriminant check,
 190    --  C is automatically visible.
 191
 192    procedure Make_Index
 193      (N            : Node_Id;
 194       Related_Nod  : Node_Id;
 195       Related_Id   : Entity_Id := Empty;
 196       Suffix_Index : Pos       := 1);
 197    --  Process an index that is given in an array declaration, an entry
 198    --  family declaration or a loop iteration. The index is given by an index
 199    --  declaration (a 'box'), or by a discrete range. The later can be the name
 200    --  of a discrete type, or a subtype indication.
 201    --
 202    --  Related_Nod is the node where the potential generated implicit types
 203    --  will be inserted. The next last parameters are used for creating the
 204    --  name.
 205
 206    procedure Make_Class_Wide_Type (T : Entity_Id);
 207    --  A Class_Wide_Type is created for each tagged type definition. The
 208    --  attributes of a class-wide type are inherited from those of the type T.
 209    --  If T is introduced by a private declaration, the corresponding class
 210    --  wide type is created at the same time, and therefore there is a private
 211    --  and a full declaration for the class-wide type as well.
 212
 213    function OK_For_Limited_Init_In_05
 214      (Typ : Entity_Id;
 215       Exp : Node_Id) return Boolean;
 216    --  Presuming Exp is an expression of an inherently limited type Typ,
 217    --  returns True if the expression is allowed in an initialization context
 218    --  by the rules of Ada 2005. We use the rule in RM-7.5(2.1/2), "...it is an
 219    --  aggregate, a function_call, or a parenthesized expression or qualified
 220    --  expression whose operand is permitted...". Note that in Ada 95 mode,
 221    --  we sometimes wish to give warnings based on whether the program _would_
 222    --  be legal in Ada 2005. Note that Exp must already have been resolved,
 223    --  so we can know whether it's a function call (as opposed to an indexed
 224    --  component, for example). In the case where Typ is a limited interface's
 225    --  class-wide type, then the expression is allowed to be of any kind if its
 226    --  type is a nonlimited descendant of the interface.
 227
 228    function OK_For_Limited_Init
 229      (Typ : Entity_Id;
 230       Exp : Node_Id) return Boolean;
 231    --  Always False in Ada 95 mode. Equivalent to OK_For_Limited_Init_In_05 in
 232    --  Ada 2005 mode.
 233
 234    procedure Preanalyze_Assert_Expression (N : Node_Id; T : Entity_Id);
 235    --  Wrapper on Preanalyze_Spec_Expression for assertion expressions, so that
 236    --  In_Assertion_Expr can be properly adjusted.
 237
 238    procedure Preanalyze_Assert_Expression (N : Node_Id);
 239    --  Similar to the above, but without forcing N to be of a particular type
 240
 241    procedure Preanalyze_Spec_Expression (N : Node_Id; T : Entity_Id);
 242    --  Default and per object expressions do not freeze their components, and
 243    --  must be analyzed and resolved accordingly. The analysis is done by
 244    --  calling the Preanalyze_And_Resolve routine and setting the global
 245    --  In_Spec_Expression flag. See the documentation section entitled
 246    --  "Handling of Default and Per-Object Expressions" in sem.ads for full
 247    --  details. N is the expression to be analyzed, T is the expected type.
 248    --  This mechanism is also used for aspect specifications that have an
 249    --  expression parameter that needs similar preanalysis.
 250
 251    procedure Process_Full_View (N : Node_Id; Full_T, Priv_T : Entity_Id);
 252    --  Process some semantic actions when the full view of a private type is
 253    --  encountered and analyzed. The first action is to create the full views
 254    --  of the dependant private subtypes. The second action is to recopy the
 255    --  primitive operations of the private view (in the tagged case).
 256    --  N is the N_Full_Type_Declaration node.
 257    --
 258    --  Full_T is the full view of the type whose full declaration is in N.
 259    --
 260    --  Priv_T is the private view of the type whose full declaration is in N.
 261
 262    procedure Process_Range_Expr_In_Decl
 263      (R          : Node_Id;
 264       T          : Entity_Id;
 265       Subtyp     : Entity_Id := Empty;
 266       Check_List : List_Id   := No_List);
 267    --  Process a range expression that appears in a declaration context. The
 268    --  range is analyzed and resolved with the base type of the given type, and
 269    --  an appropriate check for expressions in non-static contexts made on the
 270    --  bounds. R is analyzed and resolved using T, so the caller should if
 271    --  necessary link R into the tree before the call, and in particular in the
 272    --  case of a subtype declaration, it is appropriate to set the parent
 273    --  pointer of R so that the types get properly frozen. Check_List is used
 274    --  when the subprogram is called from Build_Record_Init_Proc and is used to
 275    --  return a set of constraint checking statements generated by the Checks
 276    --  package.
 277    --
 278    --  If Subtyp is given, then the range is for the named subtype Subtyp, and
 279    --  in this case the bounds are captured if necessary using this name.
 280
 281    function Process_Subtype
 282      (S           : Node_Id;
 283       Related_Nod : Node_Id;
 284       Related_Id  : Entity_Id := Empty;
 285       Suffix      : Character := ' ') return Entity_Id;
 286    --  Process a subtype indication S and return corresponding entity.
 287    --  Related_Nod is the node where the potential generated implicit types
 288    --  will be inserted. The Related_Id and Suffix parameters are used to
 289    --  build the associated Implicit type name.
 290
 291    procedure Process_Discriminants
 292      (N    : Node_Id;
 293       Prev : Entity_Id := Empty);
 294    --  Process the discriminants contained in an N_Full_Type_Declaration or
 295    --  N_Incomplete_Type_Decl node N. If the declaration is a completion, Prev
 296    --  is entity on the partial view, on which references are posted. However,
 297    --  note that Process_Discriminants is called for a completion only if
 298    --  partial view had no discriminants (else we just check conformance
 299    --  between the two views and do not call Process_Discriminants again
 300    --  for the completion).
 301
 302    function Replace_Anonymous_Access_To_Protected_Subprogram
 303      (N : Node_Id) return Entity_Id;
 304    --  Ada 2005 (AI-254): Create and decorate an internal full type declaration
 305    --  for an anonymous access to protected subprogram. For a record component
 306    --  declaration, the type is created in the enclosing scope, for an array
 307    --  type declaration or an object declaration it is simply placed ahead of
 308    --  this declaration.
 309
 310    procedure Set_Completion_Referenced (E : Entity_Id);
 311    --  If E is the completion of a private or incomplete  type declaration,
 312    --  or the completion of a deferred constant declaration, mark the entity
 313    --  as referenced. Warnings on unused entities, if needed, go on the
 314    --  partial view.
 315
 316 end Sem_Ch3;