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) 1992-2020, 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_Simple_Return_Statement         (N : Node_Id);
  45    procedure Analyze_Subprogram_Declaration          (N : Node_Id);
  46    procedure Analyze_Subprogram_Body                 (N : Node_Id);
  47
  48    function Analyze_Subprogram_Specification (N : Node_Id) return Entity_Id;
  49    --  Analyze subprogram specification in both subprogram declarations
  50    --  and body declarations. Returns the defining entity for the
  51    --  specification N.
  52
  53    procedure Check_Conventions (Typ : Entity_Id);
  54    --  Ada 2005 (AI-430): Check that the conventions of all inherited and
  55    --  overridden dispatching operations of type Typ are consistent with their
  56    --  respective counterparts.
  57
  58    procedure Check_Delayed_Subprogram (Designator : Entity_Id);
  59    --  Designator can be a E_Subprogram_Type, E_Procedure or E_Function. If a
  60    --  type in its profile depends on a private type without a full
  61    --  declaration, indicate that the subprogram or type is delayed.
  62
  63    procedure Check_Discriminant_Conformance
  64      (N        : Node_Id;
  65       Prev     : Entity_Id;
  66       Prev_Loc : Node_Id);
  67    --  Check that the discriminants of a full type N fully conform to the
  68    --  discriminants of the corresponding partial view Prev. Prev_Loc indicates
  69    --  the source location of the partial view, which may be different than
  70    --  Prev in the case of private types.
  71
  72    procedure Check_Formal_Subprogram_Conformance
  73      (New_Id  : Entity_Id;
  74       Old_Id  : Entity_Id;
  75       Err_Loc : Node_Id := Empty);
  76    --  Check RM 6.3.1(17/3): the profile of a generic formal subprogram is not
  77    --  subtype conformant with any other profile and post an error message if
  78    --  either New_Id or Old_Id denotes a formal subprogram, with the flag being
  79    --  placed on the Err_Loc node if it is specified, and on New_Id if not. See
  80    --  also spec of Check_Fully_Conformant below for New_Id and Old_Id usage.
  81
  82    procedure Check_Fully_Conformant
  83      (New_Id  : Entity_Id;
  84       Old_Id  : Entity_Id;
  85       Err_Loc : Node_Id := Empty);
  86    --  Check that two callable entities (subprograms, entries, literals)
  87    --  are fully conformant, post error message if not (RM 6.3.1(17)) with
  88    --  the flag being placed on the Err_Loc node if it is specified, and
  89    --  on the appropriate component of the New_Id construct if not. Note:
  90    --  when checking spec/body conformance, New_Id must be the body entity
  91    --  and Old_Id is the spec entity (the code in the implementation relies
  92    --  on this ordering, and in any case, this makes sense, since if flags
  93    --  are to be placed on the construct, they clearly belong on the body.
  94
  95    procedure Check_Mode_Conformant
  96      (New_Id   : Entity_Id;
  97       Old_Id   : Entity_Id;
  98       Err_Loc  : Node_Id := Empty;
  99       Get_Inst : Boolean := False);
 100    --  Check that two callable entities (subprograms, entries, literals)
 101    --  are mode conformant, post error message if not (RM 6.3.1(15)) with
 102    --  the flag being placed on the Err_Loc node if it is specified, and
 103    --  on the appropriate component of the New_Id construct if not. The
 104    --  argument Get_Inst is set to True when this is a check against a
 105    --  formal access-to-subprogram type, indicating that mapping of types
 106    --  is needed.
 107
 108    procedure Check_Overriding_Indicator
 109      (Subp            : Entity_Id;
 110       Overridden_Subp : Entity_Id;
 111       Is_Primitive    : Boolean);
 112    --  Verify the consistency of an overriding_indicator given for subprogram
 113    --  declaration, body, renaming, or instantiation. Overridden_Subp is set
 114    --  if the scope where we are introducing the subprogram contains a
 115    --  type-conformant subprogram that becomes hidden by the new subprogram.
 116    --  Is_Primitive indicates whether the subprogram is primitive.
 117
 118    procedure Check_Subtype_Conformant
 119      (New_Id                   : Entity_Id;
 120       Old_Id                   : Entity_Id;
 121       Err_Loc                  : Node_Id := Empty;
 122       Skip_Controlling_Formals : Boolean := False;
 123       Get_Inst                 : Boolean := False);
 124    --  Check that two callable entities (subprograms, entries, literals)
 125    --  are subtype conformant, post error message if not (RM 6.3.1(16)),
 126    --  the flag being placed on the Err_Loc node if it is specified, and
 127    --  on the appropriate component of the New_Id construct if not.
 128    --  Skip_Controlling_Formals is True when checking the conformance of
 129    --  a subprogram that implements an interface operation. In that case,
 130    --  only the non-controlling formals can (and must) be examined. The
 131    --  argument Get_Inst is set to True when this is a check against a
 132    --  formal access-to-subprogram type, indicating that mapping of types
 133    --  is needed.
 134
 135    procedure Check_Synchronized_Overriding
 136      (Def_Id          : Entity_Id;
 137       Overridden_Subp : out Entity_Id);
 138    --  First determine if Def_Id is an entry or a subprogram either defined in
 139    --  the scope of a task or protected type, or that is a primitive of such
 140    --  a type. Check whether Def_Id overrides a subprogram of an interface
 141    --  implemented by the synchronized type, returning the overridden entity
 142    --  or Empty.
 143
 144    procedure Check_Type_Conformant
 145      (New_Id  : Entity_Id;
 146       Old_Id  : Entity_Id;
 147       Err_Loc : Node_Id := Empty);
 148    --  Check that two callable entities (subprograms, entries, literals)
 149    --  are type conformant, post error message if not (RM 6.3.1(14)) with
 150    --  the flag being placed on the Err_Loc node if it is specified, and
 151    --  on the appropriate component of the New_Id construct if not.
 152
 153    function Conforming_Types
 154      (T1       : Entity_Id;
 155       T2       : Entity_Id;
 156       Ctype    : Conformance_Type;
 157       Get_Inst : Boolean := False) return Boolean;
 158    --  Check that the types of two formal parameters are conforming. In most
 159    --  cases this is just a name comparison, but within an instance it involves
 160    --  generic actual types, and in the presence of anonymous access types
 161    --  it must examine the designated types. The argument Get_Inst is set to
 162    --  True when this is a check against a formal access-to-subprogram type,
 163    --  indicating that mapping of types is needed.
 164
 165    procedure Create_Extra_Formals (E : Entity_Id);
 166    --  For each parameter of a subprogram or entry that requires an additional
 167    --  formal (such as for access parameters and indefinite discriminated
 168    --  parameters), creates the appropriate formal and attach it to its
 169    --  associated parameter. Each extra formal will also be appended to
 170    --  the end of Subp's parameter list (with each subsequent extra formal
 171    --  being attached to the preceding extra formal).
 172
 173    function Find_Corresponding_Spec
 174      (N          : Node_Id;
 175       Post_Error : Boolean := True) return Entity_Id;
 176    --  Use the subprogram specification in the body to retrieve the previous
 177    --  subprogram declaration, if any.
 178
 179    function Fully_Conformant (New_Id, Old_Id : Entity_Id) return Boolean;
 180    --  Determine whether two callable entities (subprograms, entries,
 181    --  literals) are fully conformant (RM 6.3.1(17))
 182
 183    function Fully_Conformant_Expressions
 184      (Given_E1 : Node_Id;
 185       Given_E2 : Node_Id;
 186       Report   : Boolean := False) return Boolean;
 187    --  Determines if two (non-empty) expressions are fully conformant
 188    --  as defined by (RM 6.3.1(18-21))
 189
 190    function Fully_Conformant_Discrete_Subtypes
 191       (Given_S1 : Node_Id;
 192        Given_S2 : Node_Id) return Boolean;
 193    --  Determines if two subtype definitions are fully conformant. Used
 194    --  for entry family conformance checks (RM 6.3.1 (24)).
 195
 196    procedure Install_Entity (E : Entity_Id);
 197    --  Place a single entity on the visibility chain
 198
 199    procedure Install_Formals (Id : Entity_Id);
 200    --  On entry to a subprogram body, make the formals visible. Note that
 201    --  simply placing the subprogram on the scope stack is not sufficient:
 202    --  the formals must become the current entities for their names. This
 203    --  procedure is also used to get visibility to the formals when analyzing
 204    --  preconditions and postconditions appearing in the spec.
 205
 206    function Is_Interface_Conformant
 207      (Tagged_Type : Entity_Id;
 208       Iface_Prim  : Entity_Id;
 209       Prim        : Entity_Id) return Boolean;
 210    --  Returns true if both primitives have a matching name (including support
 211    --  for names of inherited private primitives --which have suffix 'P'), they
 212    --  are type conformant, and Prim is defined in the scope of Tagged_Type.
 213    --  Special management is done for functions returning interfaces.
 214
 215    procedure List_Inherited_Pre_Post_Aspects (E : Entity_Id);
 216    --  E is the entity for a subprogram or generic subprogram spec. This call
 217    --  lists all inherited Pre/Post aspects if List_Inherited_Pre_Post is True.
 218
 219    procedure May_Need_Actuals (Fun : Entity_Id);
 220    --  Flag functions that can be called without parameters, i.e. those that
 221    --  have no parameters, or those for which defaults exist for all parameters
 222    --  Used for subprogram declarations and for access subprogram declarations,
 223    --  where they apply to the anonymous designated type. On return the flag
 224    --  Set_Needs_No_Actuals is set appropriately in Fun.
 225
 226    function Mode_Conformant (New_Id, Old_Id : Entity_Id) return Boolean;
 227    --  Determine whether two callable entities (subprograms, entries,
 228    --  literals) are mode conformant (RM 6.3.1(15))
 229
 230    procedure New_Overloaded_Entity
 231      (S            : Entity_Id;
 232       Derived_Type : Entity_Id := Empty);
 233    --  Process new overloaded entity. Overloaded entities are created by
 234    --  enumeration type declarations, subprogram specifications, entry
 235    --  declarations, and (implicitly) by type derivations. If Derived_Type
 236    --  is non-empty then this is a subprogram derived for that type.
 237
 238    procedure Process_Formals (T : List_Id; Related_Nod : Node_Id);
 239    --  Enter the formals in the scope of the subprogram or entry, and
 240    --  analyze default expressions if any. The implicit types created for
 241    --  access parameter are attached to the Related_Nod which comes from the
 242    --  context.
 243
 244    procedure Reference_Body_Formals (Spec : Entity_Id; Bod : Entity_Id);
 245    --  If there is a separate spec for a subprogram or generic subprogram, the
 246    --  formals of the body are treated as references to the corresponding
 247    --  formals of the spec. This reference does not count as an actual use of
 248    --  the formal, in order to diagnose formals that are unused in the body.
 249    --  This procedure is also used in renaming_as_body declarations, where
 250    --  the formals of the specification must be treated as body formals that
 251    --  correspond to the previous subprogram declaration, and not as new
 252    --  entities with their defining entry in the cross-reference information.
 253
 254    procedure Set_Actual_Subtypes (N : Node_Id; Subp : Entity_Id);
 255    --  If the formals of a subprogram are unconstrained, build a subtype
 256    --  declaration that uses the bounds or discriminants of the actual to
 257    --  construct an actual subtype for them. This is an optimization that
 258    --  is done only in some cases where the actual subtype cannot change
 259    --  during execution of the subprogram. By setting the actual subtype
 260    --  once, we avoid recomputing it unnecessarily.
 261
 262    procedure Set_Formal_Mode (Formal_Id : Entity_Id);
 263    --  Set proper Ekind to reflect formal mode (in, out, in out)
 264
 265    function Subtype_Conformant
 266      (New_Id                   : Entity_Id;
 267       Old_Id                   : Entity_Id;
 268       Skip_Controlling_Formals : Boolean := False) return Boolean;
 269    --  Determine whether two callable entities (subprograms, entries, literals)
 270    --  are subtype conformant (RM 6.3.1(16)). Skip_Controlling_Formals is True
 271    --  when checking the conformance of a subprogram that implements an
 272    --  interface operation. In that case, only the non-controlling formals
 273    --  can (and must) be examined.
 274
 275    function Type_Conformant
 276      (New_Id                   : Entity_Id;
 277       Old_Id                   : Entity_Id;
 278       Skip_Controlling_Formals : Boolean := False) return Boolean;
 279    --  Determine whether two callable entities (subprograms, entries, literals)
 280    --  are type conformant (RM 6.3.1(14)). Skip_Controlling_Formals is True
 281    --  when checking the conformance of a subprogram that implements an
 282    --  interface operation. In that case, only the non-controlling formals
 283    --  can (and must) be examined.
 284
 285    procedure Valid_Operator_Definition (Designator : Entity_Id);
 286    --  Verify that an operator definition has the proper number of formals
 287
 288 end Sem_Ch6;