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) 1992-2013, 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    procedure Analyze_Subprogram_Body_Contract (Body_Id : Entity_Id);
  49    --  Analyze all delayed aspects chained on the contract of subprogram body
  50    --  Body_Id as if they appeared at the end of a declarative region. The
  51    --  aspects in question are:
  52    --    Refined_Depends
  53    --    Refined_Global
  54
  55    procedure Analyze_Subprogram_Contract (Subp : Entity_Id);
  56    --  Analyze all delayed aspects chained on the contract of subprogram Subp
  57    --  as if they appeared at the end of a declarative region. The aspects in
  58    --  question are:
  59    --    Contract_Cases
  60    --    Postcondition
  61    --    Precondition
  62    --    Test_Case
  63
  64    function Analyze_Subprogram_Specification (N : Node_Id) return Entity_Id;
  65    --  Analyze subprogram specification in both subprogram declarations
  66    --  and body declarations. Returns the defining entity for the
  67    --  specification N.
  68
  69    procedure Cannot_Inline
  70      (Msg        : String;
  71       N          : Node_Id;
  72       Subp       : Entity_Id;
  73       Is_Serious : Boolean := False);
  74    --  This procedure is called if the node N, an instance of a call to
  75    --  subprogram Subp, cannot be inlined. Msg is the message to be issued,
  76    --  which ends with ? (it does not end with ?p?, this routine takes care of
  77    --  the need to change ? to ?p?). Temporarily the behavior of this routine
  78    --  depends on the value of -gnatd.k:
  79    --
  80    --    * If -gnatd.k is not set (ie. old inlining model) then if Subp has
  81    --      a pragma Always_Inlined, then an error message is issued (by
  82    --      removing the last character of Msg). If Subp is not Always_Inlined,
  83    --      then a warning is issued if the flag Ineffective_Inline_Warnings
  84    --      is set, adding ?p to the msg, and if not, the call has no effect.
  85    --
  86    --    * If -gnatd.k is set (ie. new inlining model) then:
  87    --      - If Is_Serious is true, then an error is reported (by removing the
  88    --        last character of Msg);
  89    --
  90    --      - otherwise:
  91    --
  92    --        * Compiling without optimizations if Subp has a pragma
  93    --          Always_Inlined, then an error message is issued; if Subp is
  94    --          not Always_Inlined, then a warning is issued if the flag
  95    --          Ineffective_Inline_Warnings is set (adding p?), and if not,
  96    --          the call has no effect.
  97    --
  98    --        * Compiling with optimizations then a warning is issued if the
  99    --          flag Ineffective_Inline_Warnings is set (adding p?); otherwise
 100    --          no effect since inlining may be performed by the backend.
 101
 102    procedure Check_Conventions (Typ : Entity_Id);
 103    --  Ada 2005 (AI-430): Check that the conventions of all inherited and
 104    --  overridden dispatching operations of type Typ are consistent with their
 105    --  respective counterparts.
 106
 107    procedure Check_Delayed_Subprogram (Designator : Entity_Id);
 108    --  Designator can be a E_Subprogram_Type, E_Procedure or E_Function. If a
 109    --  type in its profile depends on a private type without a full
 110    --  declaration, indicate that the subprogram or type is delayed.
 111
 112    procedure Check_Discriminant_Conformance
 113      (N        : Node_Id;
 114       Prev     : Entity_Id;
 115       Prev_Loc : Node_Id);
 116    --  Check that the discriminants of a full type N fully conform to the
 117    --  discriminants of the corresponding partial view Prev. Prev_Loc indicates
 118    --  the source location of the partial view, which may be different than
 119    --  Prev in the case of private types.
 120
 121    procedure Check_Fully_Conformant
 122      (New_Id  : Entity_Id;
 123       Old_Id  : Entity_Id;
 124       Err_Loc : Node_Id := Empty);
 125    --  Check that two callable entities (subprograms, entries, literals)
 126    --  are fully conformant, post error message if not (RM 6.3.1(17)) with
 127    --  the flag being placed on the Err_Loc node if it is specified, and
 128    --  on the appropriate component of the New_Id construct if not. Note:
 129    --  when checking spec/body conformance, New_Id must be the body entity
 130    --  and Old_Id is the spec entity (the code in the implementation relies
 131    --  on this ordering, and in any case, this makes sense, since if flags
 132    --  are to be placed on the construct, they clearly belong on the body.
 133
 134    procedure Check_Mode_Conformant
 135      (New_Id   : Entity_Id;
 136       Old_Id   : Entity_Id;
 137       Err_Loc  : Node_Id := Empty;
 138       Get_Inst : Boolean := False);
 139    --  Check that two callable entities (subprograms, entries, literals)
 140    --  are mode conformant, post error message if not (RM 6.3.1(15)) with
 141    --  the flag being placed on the Err_Loc node if it is specified, and
 142    --  on the appropriate component of the New_Id construct if not. The
 143    --  argument Get_Inst is set to True when this is a check against a
 144    --  formal access-to-subprogram type, indicating that mapping of types
 145    --  is needed.
 146
 147    procedure Check_Overriding_Indicator
 148      (Subp            : Entity_Id;
 149       Overridden_Subp : Entity_Id;
 150       Is_Primitive    : Boolean);
 151    --  Verify the consistency of an overriding_indicator given for subprogram
 152    --  declaration, body, renaming, or instantiation.  Overridden_Subp is set
 153    --  if the scope where we are introducing the subprogram contains a
 154    --  type-conformant subprogram that becomes hidden by the new subprogram.
 155    --  Is_Primitive indicates whether the subprogram is primitive.
 156
 157    procedure Check_Subtype_Conformant
 158      (New_Id                   : Entity_Id;
 159       Old_Id                   : Entity_Id;
 160       Err_Loc                  : Node_Id := Empty;
 161       Skip_Controlling_Formals : Boolean := False;
 162       Get_Inst                 : Boolean := False);
 163    --  Check that two callable entities (subprograms, entries, literals)
 164    --  are subtype conformant, post error message if not (RM 6.3.1(16)),
 165    --  the flag being placed on the Err_Loc node if it is specified, and
 166    --  on the appropriate component of the New_Id construct if not.
 167    --  Skip_Controlling_Formals is True when checking the conformance of
 168    --  a subprogram that implements an interface operation. In that case,
 169    --  only the non-controlling formals can (and must) be examined. The
 170    --  argument Get_Inst is set to True when this is a check against a
 171    --  formal access-to-subprogram type, indicating that mapping of types
 172    --  is needed.
 173
 174    procedure Check_Type_Conformant
 175      (New_Id  : Entity_Id;
 176       Old_Id  : Entity_Id;
 177       Err_Loc : Node_Id := Empty);
 178    --  Check that two callable entities (subprograms, entries, literals)
 179    --  are type conformant, post error message if not (RM 6.3.1(14)) with
 180    --  the flag being placed on the Err_Loc node if it is specified, and
 181    --  on the appropriate component of the New_Id construct if not.
 182
 183    function Conforming_Types
 184      (T1       : Entity_Id;
 185       T2       : Entity_Id;
 186       Ctype    : Conformance_Type;
 187       Get_Inst : Boolean := False) return Boolean;
 188    --  Check that the types of two formal parameters are conforming. In most
 189    --  cases this is just a name comparison, but within an instance it involves
 190    --  generic actual types, and in the presence of anonymous access types
 191    --  it must examine the designated types. The argument Get_Inst is set to
 192    --  True when this is a check against a formal access-to-subprogram type,
 193    --  indicating that mapping of types is needed.
 194
 195    procedure Create_Extra_Formals (E : Entity_Id);
 196    --  For each parameter of a subprogram or entry that requires an additional
 197    --  formal (such as for access parameters and indefinite discriminated
 198    --  parameters), creates the appropriate formal and attach it to its
 199    --  associated parameter. Each extra formal will also be appended to
 200    --  the end of Subp's parameter list (with each subsequent extra formal
 201    --  being attached to the preceding extra formal).
 202
 203    function Find_Corresponding_Spec
 204      (N          : Node_Id;
 205       Post_Error : Boolean := True) return Entity_Id;
 206    --  Use the subprogram specification in the body to retrieve the previous
 207    --  subprogram declaration, if any.
 208
 209    function Fully_Conformant (New_Id, Old_Id : Entity_Id) return Boolean;
 210    --  Determine whether two callable entities (subprograms, entries,
 211    --  literals) are fully conformant (RM 6.3.1(17))
 212
 213    function Fully_Conformant_Expressions
 214      (Given_E1 : Node_Id;
 215       Given_E2 : Node_Id) return Boolean;
 216    --  Determines if two (non-empty) expressions are fully conformant
 217    --  as defined by (RM 6.3.1(18-21))
 218
 219    function Fully_Conformant_Discrete_Subtypes
 220       (Given_S1 : Node_Id;
 221        Given_S2 : Node_Id) return Boolean;
 222    --  Determines if two subtype definitions are fully conformant. Used
 223    --  for entry family conformance checks (RM 6.3.1 (24)).
 224
 225    procedure Install_Entity (E : Entity_Id);
 226    --  Place a single entity on the visibility chain
 227
 228    procedure Install_Formals (Id : Entity_Id);
 229    --  On entry to a subprogram body, make the formals visible. Note that
 230    --  simply placing the subprogram on the scope stack is not sufficient:
 231    --  the formals must become the current entities for their names. This
 232    --  procedure is also used to get visibility to the formals when analyzing
 233    --  preconditions and postconditions appearing in the spec.
 234
 235    function Is_Interface_Conformant
 236      (Tagged_Type : Entity_Id;
 237       Iface_Prim  : Entity_Id;
 238       Prim        : Entity_Id) return Boolean;
 239    --  Returns true if both primitives have a matching name (including support
 240    --  for names of inherited private primitives --which have suffix 'P'), they
 241    --  are type conformant, and Prim is defined in the scope of Tagged_Type.
 242    --  Special management is done for functions returning interfaces.
 243
 244    procedure List_Inherited_Pre_Post_Aspects (E : Entity_Id);
 245    --  E is the entity for a subprogram or generic subprogram spec. This call
 246    --  lists all inherited Pre/Post aspects if List_Inherited_Pre_Post is True.
 247
 248    procedure May_Need_Actuals (Fun : Entity_Id);
 249    --  Flag functions that can be called without parameters, i.e. those that
 250    --  have no parameters, or those for which defaults exist for all parameters
 251    --  Used for subprogram declarations and for access subprogram declarations,
 252    --  where they apply to the anonymous designated type. On return the flag
 253    --  Set_Needs_No_Actuals is set appropriately in Fun.
 254
 255    function Mode_Conformant (New_Id, Old_Id : Entity_Id) return Boolean;
 256    --  Determine whether two callable entities (subprograms, entries,
 257    --  literals) are mode conformant (RM 6.3.1(15))
 258
 259    procedure New_Overloaded_Entity
 260      (S            : Entity_Id;
 261       Derived_Type : Entity_Id := Empty);
 262    --  Process new overloaded entity. Overloaded entities are created by
 263    --  enumeration type declarations, subprogram specifications, entry
 264    --  declarations, and (implicitly) by type derivations. If Derived_Type
 265    --  is non-empty then this is a subprogram derived for that type.
 266
 267    procedure Process_Formals (T : List_Id; Related_Nod : Node_Id);
 268    --  Enter the formals in the scope of the subprogram or entry, and
 269    --  analyze default expressions if any. The implicit types created for
 270    --  access parameter are attached to the Related_Nod which comes from the
 271    --  context.
 272
 273    procedure Reference_Body_Formals (Spec : Entity_Id; Bod : Entity_Id);
 274    --  If there is a separate spec for a subprogram or generic subprogram, the
 275    --  formals of the body are treated as references to the corresponding
 276    --  formals of the spec. This reference does not count as an actual use of
 277    --  the formal, in order to diagnose formals that are unused in the body.
 278    --  This procedure is also used in renaming_as_body declarations, where
 279    --  the formals of the specification must be treated as body formals that
 280    --  correspond to the previous subprogram declaration, and not as new
 281    --  entities with their defining entry in the cross-reference information.
 282
 283    procedure Set_Actual_Subtypes (N : Node_Id; Subp : Entity_Id);
 284    --  If the formals of a subprogram are unconstrained, build a subtype
 285    --  declaration that uses the bounds or discriminants of the actual to
 286    --  construct an actual subtype for them. This is an optimization that
 287    --  is done only in some cases where the actual subtype cannot change
 288    --  during execution of the subprogram. By setting the actual subtype
 289    --  once, we avoid recomputing it unnecessarily.
 290
 291    procedure Set_Formal_Mode (Formal_Id : Entity_Id);
 292    --  Set proper Ekind to reflect formal mode (in, out, in out)
 293
 294    function Subtype_Conformant
 295      (New_Id                   : Entity_Id;
 296       Old_Id                   : Entity_Id;
 297       Skip_Controlling_Formals : Boolean := False) return Boolean;
 298    --  Determine whether two callable entities (subprograms, entries, literals)
 299    --  are subtype conformant (RM 6.3.1(16)). Skip_Controlling_Formals is True
 300    --  when checking the conformance of a subprogram that implements an
 301    --  interface operation. In that case, only the non-controlling formals
 302    --  can (and must) be examined.
 303
 304    function Type_Conformant
 305      (New_Id                   : Entity_Id;
 306       Old_Id                   : Entity_Id;
 307       Skip_Controlling_Formals : Boolean := False) return Boolean;
 308    --  Determine whether two callable entities (subprograms, entries, literals)
 309    --  are type conformant (RM 6.3.1(14)). Skip_Controlling_Formals is True
 310    --  when checking the conformance of a subprogram that implements an
 311    --  interface operation. In that case, only the non-controlling formals
 312    --  can (and must) be examined.
 313
 314    procedure Valid_Operator_Definition (Designator : Entity_Id);
 315    --  Verify that an operator definition has the proper number of formals
 316
 317 end Sem_Ch6;