gcc/ada/sem_ch6.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              S E M _ C H 6                               --
   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 package Sem_Ch6 is
  28
  29    type Conformance_Type is
  30      (Type_Conformant, Mode_Conformant, Subtype_Conformant, Fully_Conformant);
  31    pragma Ordered (Conformance_Type);
  32    --  Conformance type used in conformance checks between specs and bodies,
  33    --  and for overriding. The literals match the RM definitions of the
  34    --  corresponding terms. This is an ordered type, since each conformance
  35    --  type is stronger than the ones preceding it.
  36
  37    procedure Analyze_Abstract_Subprogram_Declaration (N : Node_Id);
  38    procedure Analyze_Expression_Function             (N : Node_Id);
  39    procedure Analyze_Extended_Return_Statement       (N : Node_Id);
  40    procedure Analyze_Function_Call                   (N : Node_Id);
  41    procedure Analyze_Operator_Symbol                 (N : Node_Id);
  42    procedure Analyze_Parameter_Association           (N : Node_Id);
  43    procedure Analyze_Procedure_Call                  (N : Node_Id);
  44    procedure Analyze_Return_When_Statement           (N : Node_Id);
  45    procedure Analyze_Simple_Return_Statement         (N : Node_Id);
  46    procedure Analyze_Subprogram_Declaration          (N : Node_Id);
  47    procedure Analyze_Subprogram_Body                 (N : Node_Id);
  48
  49    function Analyze_Subprogram_Specification (N : Node_Id) return Entity_Id;
  50    --  Analyze subprogram specification in both subprogram declarations
  51    --  and body declarations. Returns the defining entity for the
  52    --  specification N.
  53
  54    procedure Analyze_SPARK_Subprogram_Specification (N : Node_Id);
  55    --  Check SPARK legality rules that require that the specification has been
  56    --  analyzed already.
  57
  58    function Can_Override_Operator (Subp : Entity_Id) return Boolean;
  59    --  Returns true if Subp can override a predefined operator
  60
  61    procedure Check_Conventions (Typ : Entity_Id);
  62    --  Ada 2005 (AI-430): Check that the conventions of all inherited and
  63    --  overridden dispatching operations of type Typ are consistent with their
  64    --  respective counterparts.
  65
  66    procedure Check_Delayed_Subprogram (Designator : Entity_Id);
  67    --  Designator can be a E_Subprogram_Type, E_Procedure or E_Function. If a
  68    --  type in its profile depends on a private type without a full
  69    --  declaration, indicate that the subprogram or type is delayed.
  70
  71    procedure Check_Discriminant_Conformance
  72      (N        : Node_Id;
  73       Prev     : Entity_Id;
  74       Prev_Loc : Node_Id);
  75    --  Check that the discriminants of a full type N fully conform to the
  76    --  discriminants of the corresponding partial view Prev. Prev_Loc indicates
  77    --  the source location of the partial view, which may be different than
  78    --  Prev in the case of private types.
  79
  80    procedure Check_Formal_Subprogram_Conformance
  81      (New_Id  : Entity_Id;
  82       Old_Id  : Entity_Id;
  83       Err_Loc : Node_Id := Empty);
  84    --  Check RM 6.3.1(17/3): the profile of a generic formal subprogram is not
  85    --  subtype conformant with any other profile and post an error message if
  86    --  either New_Id or Old_Id denotes a formal subprogram, with the flag being
  87    --  placed on the Err_Loc node if it is specified, and on New_Id if not. See
  88    --  also spec of Check_Fully_Conformant below for New_Id and Old_Id usage.
  89
  90    procedure Check_Fully_Conformant
  91      (New_Id  : Entity_Id;
  92       Old_Id  : Entity_Id;
  93       Err_Loc : Node_Id := Empty);
  94    --  Check that two callable entities (subprograms, entries, literals)
  95    --  are fully conformant, post error message if not (RM 6.3.1(17)) with
  96    --  the flag being placed on the Err_Loc node if it is specified, and
  97    --  on the appropriate component of the New_Id construct if not. Note:
  98    --  when checking spec/body conformance, New_Id must be the body entity
  99    --  and Old_Id is the spec entity (the code in the implementation relies
 100    --  on this ordering, and in any case, this makes sense, since if flags
 101    --  are to be placed on the construct, they clearly belong on the body.
 102
 103    procedure Check_Mode_Conformant
 104      (New_Id   : Entity_Id;
 105       Old_Id   : Entity_Id;
 106       Err_Loc  : Node_Id := Empty;
 107       Get_Inst : Boolean := False);
 108    --  Check that two callable entities (subprograms, entries, literals)
 109    --  are mode conformant, post error message if not (RM 6.3.1(15)) with
 110    --  the flag being placed on the Err_Loc node if it is specified, and
 111    --  on the appropriate component of the New_Id construct if not. The
 112    --  argument Get_Inst is set to True when this is a check against a
 113    --  formal access-to-subprogram type, indicating that mapping of types
 114    --  is needed.
 115
 116    procedure Check_Overriding_Indicator
 117      (Subp            : Entity_Id;
 118       Overridden_Subp : Entity_Id;
 119       Is_Primitive    : Boolean);
 120    --  Verify the consistency of an overriding_indicator given for subprogram
 121    --  declaration, body, renaming, or instantiation. Overridden_Subp is set
 122    --  if the scope where we are introducing the subprogram contains a
 123    --  type-conformant subprogram that becomes hidden by the new subprogram.
 124    --  Is_Primitive indicates whether the subprogram is primitive.
 125
 126    procedure Check_Subtype_Conformant
 127      (New_Id                   : Entity_Id;
 128       Old_Id                   : Entity_Id;
 129       Err_Loc                  : Node_Id := Empty;
 130       Skip_Controlling_Formals : Boolean := False;
 131       Get_Inst                 : Boolean := False);
 132    --  Check that two callable entities (subprograms, entries, literals)
 133    --  are subtype conformant, post error message if not (RM 6.3.1(16)),
 134    --  the flag being placed on the Err_Loc node if it is specified, and
 135    --  on the appropriate component of the New_Id construct if not.
 136    --  Skip_Controlling_Formals is True when checking the conformance of
 137    --  a subprogram that implements an interface operation. In that case,
 138    --  only the non-controlling formals can (and must) be examined. The
 139    --  argument Get_Inst is set to True when this is a check against a
 140    --  formal access-to-subprogram type, indicating that mapping of types
 141    --  is needed.
 142
 143    procedure Check_Synchronized_Overriding
 144      (Def_Id          : Entity_Id;
 145       Overridden_Subp : out Entity_Id);
 146    --  First determine if Def_Id is an entry or a subprogram either defined in
 147    --  the scope of a task or protected type, or that is a primitive of such
 148    --  a type. Check whether Def_Id overrides a subprogram of an interface
 149    --  implemented by the synchronized type, returning the overridden entity
 150    --  or Empty.
 151
 152    procedure Check_Type_Conformant
 153      (New_Id  : Entity_Id;
 154       Old_Id  : Entity_Id;
 155       Err_Loc : Node_Id := Empty);
 156    --  Check that two callable entities (subprograms, entries, literals)
 157    --  are type conformant, post error message if not (RM 6.3.1(14)) with
 158    --  the flag being placed on the Err_Loc node if it is specified, and
 159    --  on the appropriate component of the New_Id construct if not.
 160
 161    function Conforming_Types
 162      (T1       : Entity_Id;
 163       T2       : Entity_Id;
 164       Ctype    : Conformance_Type;
 165       Get_Inst : Boolean := False) return Boolean;
 166    --  Check that the types of two formal parameters are conforming. In most
 167    --  cases this is just a name comparison, but within an instance it involves
 168    --  generic actual types, and in the presence of anonymous access types
 169    --  it must examine the designated types. The argument Get_Inst is set to
 170    --  True when this is a check against a formal access-to-subprogram type,
 171    --  indicating that mapping of types is needed.
 172
 173    procedure Create_Extra_Formals (E : Entity_Id);
 174    --  For each parameter of a subprogram or entry that requires an additional
 175    --  formal (such as for access parameters and indefinite discriminated
 176    --  parameters), creates the appropriate formal and attach it to its
 177    --  associated parameter. Each extra formal will also be appended to
 178    --  the end of Subp's parameter list (with each subsequent extra formal
 179    --  being attached to the preceding extra formal).
 180
 181    function Extra_Formals_Match_OK
 182      (E     : Entity_Id;
 183       Ref_E : Entity_Id) return Boolean;
 184    --  Return True if the extra formals of the given entities match. E is a
 185    --  subprogram, and Ref_E is the reference entity that will be used to check
 186    --  the extra formals of E: a subprogram type or another subprogram. For
 187    --  example, if E is a dispatching primitive of a tagged type then Ref_E
 188    --  may be the overridden primitive of its parent type or its ultimate
 189    --  renamed entity; however, if E is a subprogram to which 'Access is
 190    --  applied then Ref_E is its corresponding subprogram type. Used in
 191    --  assertions.
 192
 193    function Extra_Formals_OK (E : Entity_Id) return Boolean;
 194    --  Return True if the decoration of the attributes associated with extra
 195    --  formals are properly set. Used in assertions.
 196
 197    function Find_Corresponding_Spec
 198      (N          : Node_Id;
 199       Post_Error : Boolean := True) return Entity_Id;
 200    --  Use the subprogram specification in the body to retrieve the previous
 201    --  subprogram declaration, if any.
 202
 203    function Fully_Conformant (New_Id, Old_Id : Entity_Id) return Boolean;
 204    --  Determine whether two callable entities (subprograms, entries,
 205    --  literals) are fully conformant (RM 6.3.1(17))
 206
 207    function Fully_Conformant_Expressions
 208      (Given_E1 : Node_Id;
 209       Given_E2 : Node_Id;
 210       Report   : Boolean := False) return Boolean;
 211    --  Determines if two (non-empty) expressions are fully conformant
 212    --  as defined by (RM 6.3.1(18-21))
 213
 214    function Fully_Conformant_Discrete_Subtypes
 215       (Given_S1 : Node_Id;
 216        Given_S2 : Node_Id) return Boolean;
 217    --  Determines if two subtype definitions are fully conformant. Used
 218    --  for entry family conformance checks (RM 6.3.1 (24)).
 219
 220    function Has_BIP_Formals (E : Entity_Id) return Boolean;
 221    --  Determines if a given entity has build-in-place formals
 222
 223    procedure Install_Entity (E : Entity_Id);
 224    --  Place a single entity on the visibility chain
 225
 226    procedure Install_Formals (Id : Entity_Id);
 227    --  On entry to a subprogram body, make the formals visible. Note that
 228    --  simply placing the subprogram on the scope stack is not sufficient:
 229    --  the formals must become the current entities for their names. This
 230    --  procedure is also used to get visibility to the formals when analyzing
 231    --  preconditions and postconditions appearing in the spec.
 232
 233    function Is_Interface_Conformant
 234      (Tagged_Type : Entity_Id;
 235       Iface_Prim  : Entity_Id;
 236       Prim        : Entity_Id) return Boolean;
 237    --  Returns true if both primitives have a matching name (including support
 238    --  for names of inherited private primitives --which have suffix 'P'), they
 239    --  are type conformant, and Prim is defined in the scope of Tagged_Type.
 240    --  Special management is done for functions returning interfaces.
 241
 242    procedure List_Inherited_Pre_Post_Aspects (E : Entity_Id);
 243    --  E is the entity for a subprogram or generic subprogram spec. This call
 244    --  lists all inherited Pre/Post aspects if List_Inherited_Pre_Post is True.
 245
 246    procedure May_Need_Actuals (Fun : Entity_Id);
 247    --  Flag functions that can be called without parameters, i.e. those that
 248    --  have no parameters, or those for which defaults exist for all parameters
 249    --  Used for subprogram declarations and for access subprogram declarations,
 250    --  where they apply to the anonymous designated type. On return the flag
 251    --  Set_Needs_No_Actuals is set appropriately in Fun.
 252
 253    function Mode_Conformant (New_Id, Old_Id : Entity_Id) return Boolean;
 254    --  Determine whether two callable entities (subprograms, entries,
 255    --  literals) are mode conformant (RM 6.3.1(15))
 256
 257    procedure New_Overloaded_Entity
 258      (S            : Entity_Id;
 259       Derived_Type : Entity_Id := Empty);
 260    --  Process new overloaded entity. Overloaded entities are created by
 261    --  enumeration type declarations, subprogram specifications, entry
 262    --  declarations, and (implicitly) by type derivations. If Derived_Type
 263    --  is non-empty then this is a subprogram derived for that type.
 264
 265    procedure Process_Formals (T : List_Id; Related_Nod : Node_Id);
 266    --  Enter the formals in the scope of the subprogram or entry, and
 267    --  analyze default expressions if any. The implicit types created for
 268    --  access parameter are attached to the Related_Nod which comes from the
 269    --  context.
 270
 271    procedure Reference_Body_Formals (Spec : Entity_Id; Bod : Entity_Id);
 272    --  If there is a separate spec for a subprogram or generic subprogram, the
 273    --  formals of the body are treated as references to the corresponding
 274    --  formals of the spec. This reference does not count as an actual use of
 275    --  the formal, in order to diagnose formals that are unused in the body.
 276    --  This procedure is also used in renaming_as_body declarations, where
 277    --  the formals of the specification must be treated as body formals that
 278    --  correspond to the previous subprogram declaration, and not as new
 279    --  entities with their defining entry in the cross-reference information.
 280
 281    procedure Set_Actual_Subtypes (N : Node_Id; Subp : Entity_Id);
 282    --  If the formals of a subprogram are unconstrained, build a subtype
 283    --  declaration that uses the bounds or discriminants of the actual to
 284    --  construct an actual subtype for them. This is an optimization that
 285    --  is done only in some cases where the actual subtype cannot change
 286    --  during execution of the subprogram. By setting the actual subtype
 287    --  once, we avoid recomputing it unnecessarily.
 288
 289    function Subtype_Conformant
 290      (New_Id                   : Entity_Id;
 291       Old_Id                   : Entity_Id;
 292       Skip_Controlling_Formals : Boolean := False) return Boolean;
 293    --  Determine whether two callable entities (subprograms, entries, literals)
 294    --  are subtype conformant (RM 6.3.1(16)). Skip_Controlling_Formals is True
 295    --  when checking the conformance of a subprogram that implements an
 296    --  interface operation. In that case, only the non-controlling formals
 297    --  can (and must) be examined.
 298
 299    function Type_Conformant
 300      (New_Id                   : Entity_Id;
 301       Old_Id                   : Entity_Id;
 302       Skip_Controlling_Formals : Boolean := False) return Boolean;
 303    --  Determine whether two callable entities (subprograms, entries, literals)
 304    --  are type conformant (RM 6.3.1(14)). Skip_Controlling_Formals is True
 305    --  when checking the conformance of a subprogram that implements an
 306    --  interface operation. In that case, only the non-controlling formals
 307    --  can (and must) be examined.
 308
 309    procedure Valid_Operator_Definition (Designator : Entity_Id);
 310    --  Verify that an operator definition has the proper number of formals
 311
 312 end Sem_Ch6;