gcc/ada/sem_util.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             S E M _ U T I L                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2011, 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 Atree;    use Atree;
  27 with Casing;   use Casing;
  28 with Checks;   use Checks;
  29 with Debug;    use Debug;
  30 with Errout;   use Errout;
  31 with Elists;   use Elists;
  32 with Exp_Ch11; use Exp_Ch11;
  33 with Exp_Disp; use Exp_Disp;
  34 with Exp_Tss;  use Exp_Tss;
  35 with Exp_Util; use Exp_Util;
  36 with Fname;    use Fname;
  37 with Freeze;   use Freeze;
  38 with Lib;      use Lib;
  39 with Lib.Xref; use Lib.Xref;
  40 with Nlists;   use Nlists;
  41 with Output;   use Output;
  42 with Opt;      use Opt;
  43 with Restrict; use Restrict;
  44 with Rident;   use Rident;
  45 with Rtsfind;  use Rtsfind;
  46 with Sem;      use Sem;
  47 with Sem_Aux;  use Sem_Aux;
  48 with Sem_Attr; use Sem_Attr;
  49 with Sem_Ch8;  use Sem_Ch8;
  50 with Sem_Disp; use Sem_Disp;
  51 with Sem_Eval; use Sem_Eval;
  52 with Sem_Res;  use Sem_Res;
  53 with Sem_Type; use Sem_Type;
  54 with Sinfo;    use Sinfo;
  55 with Sinput;   use Sinput;
  56 with Stand;    use Stand;
  57 with Style;
  58 with Stringt;  use Stringt;
  59 with Table;
  60 with Targparm; use Targparm;
  61 with Tbuild;   use Tbuild;
  62 with Ttypes;   use Ttypes;
  63 with Uname;    use Uname;
  64
  65 with GNAT.HTable; use GNAT.HTable;
  66
  67 package body Sem_Util is
  68
  69    ----------------------------------------
  70    -- Global_Variables for New_Copy_Tree --
  71    ----------------------------------------
  72
  73    --  These global variables are used by New_Copy_Tree. See description
  74    --  of the body of this subprogram for details. Global variables can be
  75    --  safely used by New_Copy_Tree, since there is no case of a recursive
  76    --  call from the processing inside New_Copy_Tree.
  77
  78    NCT_Hash_Threshold : constant := 20;
  79    --  If there are more than this number of pairs of entries in the
  80    --  map, then Hash_Tables_Used will be set, and the hash tables will
  81    --  be initialized and used for the searches.
  82
  83    NCT_Hash_Tables_Used : Boolean := False;
  84    --  Set to True if hash tables are in use
  85
  86    NCT_Table_Entries : Nat;
  87    --  Count entries in table to see if threshold is reached
  88
  89    NCT_Hash_Table_Setup : Boolean := False;
  90    --  Set to True if hash table contains data. We set this True if we
  91    --  setup the hash table with data, and leave it set permanently
  92    --  from then on, this is a signal that second and subsequent users
  93    --  of the hash table must clear the old entries before reuse.
  94
  95    subtype NCT_Header_Num is Int range 0 .. 511;
  96    --  Defines range of headers in hash tables (512 headers)
  97
  98    ----------------------------------
  99    -- Order Dependence (AI05-0144) --
 100    ----------------------------------
 101
 102    --  Each actual in a call is entered into the table below. A flag indicates
 103    --  whether the corresponding formal is OUT or IN OUT. Each top-level call
 104    --  (procedure call, condition, assignment) examines all the actuals for a
 105    --  possible order dependence. The table is reset after each such check.
 106    --  The actuals to be checked in a call to Check_Order_Dependence are at
 107    --  positions 1 .. Last.
 108
 109    type Actual_Name is record
 110       Act         : Node_Id;
 111       Is_Writable : Boolean;
 112    end record;
 113
 114    package Actuals_In_Call is new Table.Table (
 115       Table_Component_Type => Actual_Name,
 116       Table_Index_Type     => Int,
 117       Table_Low_Bound      => 0,
 118       Table_Initial        => 10,
 119       Table_Increment      => 100,
 120       Table_Name           => "Actuals");
 121
 122    -----------------------
 123    -- Local Subprograms --
 124    -----------------------
 125
 126    function Build_Component_Subtype
 127      (C   : List_Id;
 128       Loc : Source_Ptr;
 129       T   : Entity_Id) return Node_Id;
 130    --  This function builds the subtype for Build_Actual_Subtype_Of_Component
 131    --  and Build_Discriminal_Subtype_Of_Component. C is a list of constraints,
 132    --  Loc is the source location, T is the original subtype.
 133
 134    function Is_Fully_Initialized_Variant (Typ : Entity_Id) return Boolean;
 135    --  Subsidiary to Is_Fully_Initialized_Type. For an unconstrained type
 136    --  with discriminants whose default values are static, examine only the
 137    --  components in the selected variant to determine whether all of them
 138    --  have a default.
 139
 140    function Has_Null_Extension (T : Entity_Id) return Boolean;
 141    --  T is a derived tagged type. Check whether the type extension is null.
 142    --  If the parent type is fully initialized, T can be treated as such.
 143
 144    procedure Mark_Non_ALFA_Subprogram_Unconditional;
 145    --  Perform the action for Mark_Non_ALFA_Subprogram_Body, which allows the
 146    --  latter to be small and inlined.
 147
 148    ------------------------------
 149    --  Abstract_Interface_List --
 150    ------------------------------
 151
 152    function Abstract_Interface_List (Typ : Entity_Id) return List_Id is
 153       Nod : Node_Id;
 154
 155    begin
 156       if Is_Concurrent_Type (Typ) then
 157
 158          --  If we are dealing with a synchronized subtype, go to the base
 159          --  type, whose declaration has the interface list.
 160
 161          --  Shouldn't this be Declaration_Node???
 162
 163          Nod := Parent (Base_Type (Typ));
 164
 165          if Nkind (Nod) = N_Full_Type_Declaration then
 166             return Empty_List;
 167          end if;
 168
 169       elsif Ekind (Typ) = E_Record_Type_With_Private then
 170          if Nkind (Parent (Typ)) = N_Full_Type_Declaration then
 171             Nod := Type_Definition (Parent (Typ));
 172
 173          elsif Nkind (Parent (Typ)) = N_Private_Type_Declaration then
 174             if Present (Full_View (Typ))
 175               and then Nkind (Parent (Full_View (Typ)))
 176                          = N_Full_Type_Declaration
 177             then
 178                Nod := Type_Definition (Parent (Full_View (Typ)));
 179
 180             --  If the full-view is not available we cannot do anything else
 181             --  here (the source has errors).
 182
 183             else
 184                return Empty_List;
 185             end if;
 186
 187          --  Support for generic formals with interfaces is still missing ???
 188
 189          elsif Nkind (Parent (Typ)) = N_Formal_Type_Declaration then
 190             return Empty_List;
 191
 192          else
 193             pragma Assert
 194               (Nkind (Parent (Typ)) = N_Private_Extension_Declaration);
 195             Nod := Parent (Typ);
 196          end if;
 197
 198       elsif Ekind (Typ) = E_Record_Subtype then
 199          Nod := Type_Definition (Parent (Etype (Typ)));
 200
 201       elsif Ekind (Typ) = E_Record_Subtype_With_Private then
 202
 203          --  Recurse, because parent may still be a private extension. Also
 204          --  note that the full view of the subtype or the full view of its
 205          --  base type may (both) be unavailable.
 206
 207          return Abstract_Interface_List (Etype (Typ));
 208
 209       else pragma Assert ((Ekind (Typ)) = E_Record_Type);
 210          if Nkind (Parent (Typ)) = N_Formal_Type_Declaration then
 211             Nod := Formal_Type_Definition (Parent (Typ));
 212          else
 213             Nod := Type_Definition (Parent (Typ));
 214          end if;
 215       end if;
 216
 217       return Interface_List (Nod);
 218    end Abstract_Interface_List;
 219
 220    --------------------------------
 221    -- Add_Access_Type_To_Process --
 222    --------------------------------
 223
 224    procedure Add_Access_Type_To_Process (E : Entity_Id; A : Entity_Id) is
 225       L : Elist_Id;
 226
 227    begin
 228       Ensure_Freeze_Node (E);
 229       L := Access_Types_To_Process (Freeze_Node (E));
 230
 231       if No (L) then
 232          L := New_Elmt_List;
 233          Set_Access_Types_To_Process (Freeze_Node (E), L);
 234       end if;
 235
 236       Append_Elmt (A, L);
 237    end Add_Access_Type_To_Process;
 238
 239    ----------------------------
 240    -- Add_Global_Declaration --
 241    ----------------------------
 242
 243    procedure Add_Global_Declaration (N : Node_Id) is
 244       Aux_Node : constant Node_Id := Aux_Decls_Node (Cunit (Current_Sem_Unit));
 245
 246    begin
 247       if No (Declarations (Aux_Node)) then
 248          Set_Declarations (Aux_Node, New_List);
 249       end if;
 250
 251       Append_To (Declarations (Aux_Node), N);
 252       Analyze (N);
 253    end Add_Global_Declaration;
 254
 255    -----------------
 256    -- Addressable --
 257    -----------------
 258
 259    --  For now, just 8/16/32/64. but analyze later if AAMP is special???
 260
 261    function Addressable (V : Uint) return Boolean is
 262    begin
 263       return V = Uint_8  or else
 264              V = Uint_16 or else
 265              V = Uint_32 or else
 266              V = Uint_64;
 267    end Addressable;
 268
 269    function Addressable (V : Int) return Boolean is
 270    begin
 271       return V = 8  or else
 272              V = 16 or else
 273              V = 32 or else
 274              V = 64;
 275    end Addressable;
 276
 277    -----------------------
 278    -- Alignment_In_Bits --
 279    -----------------------
 280
 281    function Alignment_In_Bits (E : Entity_Id) return Uint is
 282    begin
 283       return Alignment (E) * System_Storage_Unit;
 284    end Alignment_In_Bits;
 285
 286    -----------------------------------------
 287    -- Apply_Compile_Time_Constraint_Error --
 288    -----------------------------------------
 289
 290    procedure Apply_Compile_Time_Constraint_Error
 291      (N      : Node_Id;
 292       Msg    : String;
 293       Reason : RT_Exception_Code;
 294       Ent    : Entity_Id  := Empty;
 295       Typ    : Entity_Id  := Empty;
 296       Loc    : Source_Ptr := No_Location;
 297       Rep    : Boolean    := True;
 298       Warn   : Boolean    := False)
 299    is
 300       Stat   : constant Boolean := Is_Static_Expression (N);
 301       R_Stat : constant Node_Id :=
 302                  Make_Raise_Constraint_Error (Sloc (N), Reason => Reason);
 303       Rtyp   : Entity_Id;
 304
 305    begin
 306       if No (Typ) then
 307          Rtyp := Etype (N);
 308       else
 309          Rtyp := Typ;
 310       end if;
 311
 312       Discard_Node
 313         (Compile_Time_Constraint_Error (N, Msg, Ent, Loc, Warn => Warn));
 314
 315       if not Rep then
 316          return;
 317       end if;
 318
 319       --  Now we replace the node by an N_Raise_Constraint_Error node
 320       --  This does not need reanalyzing, so set it as analyzed now.
 321
 322       Rewrite (N, R_Stat);
 323       Set_Analyzed (N, True);
 324
 325       Set_Etype (N, Rtyp);
 326       Set_Raises_Constraint_Error (N);
 327
 328       --  Now deal with possible local raise handling
 329
 330       Possible_Local_Raise (N, Standard_Constraint_Error);
 331
 332       --  If the original expression was marked as static, the result is
 333       --  still marked as static, but the Raises_Constraint_Error flag is
 334       --  always set so that further static evaluation is not attempted.
 335
 336       if Stat then
 337          Set_Is_Static_Expression (N);
 338       end if;
 339    end Apply_Compile_Time_Constraint_Error;
 340
 341    --------------------------------
 342    -- Bad_Predicated_Subtype_Use --
 343    --------------------------------
 344
 345    procedure Bad_Predicated_Subtype_Use
 346      (Msg : String;
 347       N   : Node_Id;
 348       Typ : Entity_Id)
 349    is
 350    begin
 351       if Has_Predicates (Typ) then
 352          if Is_Generic_Actual_Type (Typ) then
 353             Error_Msg_FE (Msg & '?', N, Typ);
 354             Error_Msg_F ("\Program_Error will be raised at run time?", N);
 355             Insert_Action (N,
 356               Make_Raise_Program_Error (Sloc (N),
 357                 Reason => PE_Bad_Predicated_Generic_Type));
 358
 359          else
 360             Error_Msg_FE (Msg, N, Typ);
 361          end if;
 362       end if;
 363    end Bad_Predicated_Subtype_Use;
 364
 365    --------------------------
 366    -- Build_Actual_Subtype --
 367    --------------------------
 368
 369    function Build_Actual_Subtype
 370      (T : Entity_Id;
 371       N : Node_Or_Entity_Id) return Node_Id
 372    is
 373       Loc : Source_Ptr;
 374       --  Normally Sloc (N), but may point to corresponding body in some cases
 375
 376       Constraints : List_Id;
 377       Decl        : Node_Id;
 378       Discr       : Entity_Id;
 379       Hi          : Node_Id;
 380       Lo          : Node_Id;
 381       Subt        : Entity_Id;
 382       Disc_Type   : Entity_Id;
 383       Obj         : Node_Id;
 384
 385    begin
 386       Loc := Sloc (N);
 387
 388       if Nkind (N) = N_Defining_Identifier then
 389          Obj := New_Reference_To (N, Loc);
 390
 391          --  If this is a formal parameter of a subprogram declaration, and
 392          --  we are compiling the body, we want the declaration for the
 393          --  actual subtype to carry the source position of the body, to
 394          --  prevent anomalies in gdb when stepping through the code.
 395
 396          if Is_Formal (N) then
 397             declare
 398                Decl : constant Node_Id := Unit_Declaration_Node (Scope (N));
 399             begin
 400                if Nkind (Decl) = N_Subprogram_Declaration
 401                  and then Present (Corresponding_Body (Decl))
 402                then
 403                   Loc := Sloc (Corresponding_Body (Decl));
 404                end if;
 405             end;
 406          end if;
 407
 408       else
 409          Obj := N;
 410       end if;
 411
 412       if Is_Array_Type (T) then
 413          Constraints := New_List;
 414          for J in 1 .. Number_Dimensions (T) loop
 415
 416             --  Build an array subtype declaration with the nominal subtype and
 417             --  the bounds of the actual. Add the declaration in front of the
 418             --  local declarations for the subprogram, for analysis before any
 419             --  reference to the formal in the body.
 420
 421             Lo :=
 422               Make_Attribute_Reference (Loc,
 423                 Prefix         =>
 424                   Duplicate_Subexpr_No_Checks (Obj, Name_Req => True),
 425                 Attribute_Name => Name_First,
 426                 Expressions    => New_List (
 427                   Make_Integer_Literal (Loc, J)));
 428
 429             Hi :=
 430               Make_Attribute_Reference (Loc,
 431                 Prefix         =>
 432                   Duplicate_Subexpr_No_Checks (Obj, Name_Req => True),
 433                 Attribute_Name => Name_Last,
 434                 Expressions    => New_List (
 435                   Make_Integer_Literal (Loc, J)));
 436
 437             Append (Make_Range (Loc, Lo, Hi), Constraints);
 438          end loop;
 439
 440       --  If the type has unknown discriminants there is no constrained
 441       --  subtype to build. This is never called for a formal or for a
 442       --  lhs, so returning the type is ok ???
 443
 444       elsif Has_Unknown_Discriminants (T) then
 445          return T;
 446
 447       else
 448          Constraints := New_List;
 449
 450          --  Type T is a generic derived type, inherit the discriminants from
 451          --  the parent type.
 452
 453          if Is_Private_Type (T)
 454            and then No (Full_View (T))
 455
 456             --  T was flagged as an error if it was declared as a formal
 457             --  derived type with known discriminants. In this case there
 458             --  is no need to look at the parent type since T already carries
 459             --  its own discriminants.
 460
 461            and then not Error_Posted (T)
 462          then
 463             Disc_Type := Etype (Base_Type (T));
 464          else
 465             Disc_Type := T;
 466          end if;
 467
 468          Discr := First_Discriminant (Disc_Type);
 469          while Present (Discr) loop
 470             Append_To (Constraints,
 471               Make_Selected_Component (Loc,
 472                 Prefix =>
 473                   Duplicate_Subexpr_No_Checks (Obj),
 474                 Selector_Name => New_Occurrence_Of (Discr, Loc)));
 475             Next_Discriminant (Discr);
 476          end loop;
 477       end if;
 478
 479       Subt := Make_Temporary (Loc, 'S', Related_Node => N);
 480       Set_Is_Internal (Subt);
 481
 482       Decl :=
 483         Make_Subtype_Declaration (Loc,
 484           Defining_Identifier => Subt,
 485           Subtype_Indication =>
 486             Make_Subtype_Indication (Loc,
 487               Subtype_Mark => New_Reference_To (T,  Loc),
 488               Constraint  =>
 489                 Make_Index_Or_Discriminant_Constraint (Loc,
 490                   Constraints => Constraints)));
 491
 492       Mark_Rewrite_Insertion (Decl);
 493       return Decl;
 494    end Build_Actual_Subtype;
 495
 496    ---------------------------------------
 497    -- Build_Actual_Subtype_Of_Component --
 498    ---------------------------------------
 499
 500    function Build_Actual_Subtype_Of_Component
 501      (T : Entity_Id;
 502       N : Node_Id) return Node_Id
 503    is
 504       Loc       : constant Source_Ptr := Sloc (N);
 505       P         : constant Node_Id    := Prefix (N);
 506       D         : Elmt_Id;
 507       Id        : Node_Id;
 508       Indx_Type : Entity_Id;
 509
 510       Deaccessed_T : Entity_Id;
 511       --  This is either a copy of T, or if T is an access type, then it is
 512       --  the directly designated type of this access type.
 513
 514       function Build_Actual_Array_Constraint return List_Id;
 515       --  If one or more of the bounds of the component depends on
 516       --  discriminants, build  actual constraint using the discriminants
 517       --  of the prefix.
 518
 519       function Build_Actual_Record_Constraint return List_Id;
 520       --  Similar to previous one, for discriminated components constrained
 521       --  by the discriminant of the enclosing object.
 522
 523       -----------------------------------
 524       -- Build_Actual_Array_Constraint --
 525       -----------------------------------
 526
 527       function Build_Actual_Array_Constraint return List_Id is
 528          Constraints : constant List_Id := New_List;
 529          Indx        : Node_Id;
 530          Hi          : Node_Id;
 531          Lo          : Node_Id;
 532          Old_Hi      : Node_Id;
 533          Old_Lo      : Node_Id;
 534
 535       begin
 536          Indx := First_Index (Deaccessed_T);
 537          while Present (Indx) loop
 538             Old_Lo := Type_Low_Bound  (Etype (Indx));
 539             Old_Hi := Type_High_Bound (Etype (Indx));
 540
 541             if Denotes_Discriminant (Old_Lo) then
 542                Lo :=
 543                  Make_Selected_Component (Loc,
 544                    Prefix => New_Copy_Tree (P),
 545                    Selector_Name => New_Occurrence_Of (Entity (Old_Lo), Loc));
 546
 547             else
 548                Lo := New_Copy_Tree (Old_Lo);
 549
 550                --  The new bound will be reanalyzed in the enclosing
 551                --  declaration. For literal bounds that come from a type
 552                --  declaration, the type of the context must be imposed, so
 553                --  insure that analysis will take place. For non-universal
 554                --  types this is not strictly necessary.
 555
 556                Set_Analyzed (Lo, False);
 557             end if;
 558
 559             if Denotes_Discriminant (Old_Hi) then
 560                Hi :=
 561                  Make_Selected_Component (Loc,
 562                    Prefix => New_Copy_Tree (P),
 563                    Selector_Name => New_Occurrence_Of (Entity (Old_Hi), Loc));
 564
 565             else
 566                Hi := New_Copy_Tree (Old_Hi);
 567                Set_Analyzed (Hi, False);
 568             end if;
 569
 570             Append (Make_Range (Loc, Lo, Hi), Constraints);
 571             Next_Index (Indx);
 572          end loop;
 573
 574          return Constraints;
 575       end Build_Actual_Array_Constraint;
 576
 577       ------------------------------------
 578       -- Build_Actual_Record_Constraint --
 579       ------------------------------------
 580
 581       function Build_Actual_Record_Constraint return List_Id is
 582          Constraints : constant List_Id := New_List;
 583          D           : Elmt_Id;
 584          D_Val       : Node_Id;
 585
 586       begin
 587          D := First_Elmt (Discriminant_Constraint (Deaccessed_T));
 588          while Present (D) loop
 589             if Denotes_Discriminant (Node (D)) then
 590                D_Val :=  Make_Selected_Component (Loc,
 591                  Prefix => New_Copy_Tree (P),
 592                 Selector_Name => New_Occurrence_Of (Entity (Node (D)), Loc));
 593
 594             else
 595                D_Val := New_Copy_Tree (Node (D));
 596             end if;
 597
 598             Append (D_Val, Constraints);
 599             Next_Elmt (D);
 600          end loop;
 601
 602          return Constraints;
 603       end Build_Actual_Record_Constraint;
 604
 605    --  Start of processing for Build_Actual_Subtype_Of_Component
 606
 607    begin
 608       --  Why the test for Spec_Expression mode here???
 609
 610       if In_Spec_Expression then
 611          return Empty;
 612
 613       --  More comments for the rest of this body would be good ???
 614
 615       elsif Nkind (N) = N_Explicit_Dereference then
 616          if Is_Composite_Type (T)
 617            and then not Is_Constrained (T)
 618            and then not (Is_Class_Wide_Type (T)
 619                           and then Is_Constrained (Root_Type (T)))
 620            and then not Has_Unknown_Discriminants (T)
 621          then
 622             --  If the type of the dereference is already constrained, it is an
 623             --  actual subtype.
 624
 625             if Is_Array_Type (Etype (N))
 626               and then Is_Constrained (Etype (N))
 627             then
 628                return Empty;
 629             else
 630                Remove_Side_Effects (P);
 631                return Build_Actual_Subtype (T, N);
 632             end if;
 633          else
 634             return Empty;
 635          end if;
 636       end if;
 637
 638       if Ekind (T) = E_Access_Subtype then
 639          Deaccessed_T := Designated_Type (T);
 640       else
 641          Deaccessed_T := T;
 642       end if;
 643
 644       if Ekind (Deaccessed_T) = E_Array_Subtype then
 645          Id := First_Index (Deaccessed_T);
 646          while Present (Id) loop
 647             Indx_Type := Underlying_Type (Etype (Id));
 648
 649             if Denotes_Discriminant (Type_Low_Bound  (Indx_Type))
 650                  or else
 651                Denotes_Discriminant (Type_High_Bound (Indx_Type))
 652             then
 653                Remove_Side_Effects (P);
 654                return
 655                  Build_Component_Subtype
 656                    (Build_Actual_Array_Constraint, Loc, Base_Type (T));
 657             end if;
 658
 659             Next_Index (Id);
 660          end loop;
 661
 662       elsif Is_Composite_Type (Deaccessed_T)
 663         and then Has_Discriminants (Deaccessed_T)
 664         and then not Has_Unknown_Discriminants (Deaccessed_T)
 665       then
 666          D := First_Elmt (Discriminant_Constraint (Deaccessed_T));
 667          while Present (D) loop
 668             if Denotes_Discriminant (Node (D)) then
 669                Remove_Side_Effects (P);
 670                return
 671                  Build_Component_Subtype (
 672                    Build_Actual_Record_Constraint, Loc, Base_Type (T));
 673             end if;
 674
 675             Next_Elmt (D);
 676          end loop;
 677       end if;
 678
 679       --  If none of the above, the actual and nominal subtypes are the same
 680
 681       return Empty;
 682    end Build_Actual_Subtype_Of_Component;
 683
 684    -----------------------------
 685    -- Build_Component_Subtype --
 686    -----------------------------
 687
 688    function Build_Component_Subtype
 689      (C   : List_Id;
 690       Loc : Source_Ptr;
 691       T   : Entity_Id) return Node_Id
 692    is
 693       Subt : Entity_Id;
 694       Decl : Node_Id;
 695
 696    begin
 697       --  Unchecked_Union components do not require component subtypes
 698
 699       if Is_Unchecked_Union (T) then
 700          return Empty;
 701       end if;
 702
 703       Subt := Make_Temporary (Loc, 'S');
 704       Set_Is_Internal (Subt);
 705
 706       Decl :=
 707         Make_Subtype_Declaration (Loc,
 708           Defining_Identifier => Subt,
 709           Subtype_Indication =>
 710             Make_Subtype_Indication (Loc,
 711               Subtype_Mark => New_Reference_To (Base_Type (T),  Loc),
 712               Constraint  =>
 713                 Make_Index_Or_Discriminant_Constraint (Loc,
 714                   Constraints => C)));
 715
 716       Mark_Rewrite_Insertion (Decl);
 717       return Decl;
 718    end Build_Component_Subtype;
 719
 720    ---------------------------
 721    -- Build_Default_Subtype --
 722    ---------------------------
 723
 724    function Build_Default_Subtype
 725      (T : Entity_Id;
 726       N : Node_Id) return Entity_Id
 727    is
 728       Loc  : constant Source_Ptr := Sloc (N);
 729       Disc : Entity_Id;
 730
 731    begin
 732       if not Has_Discriminants (T) or else Is_Constrained (T) then
 733          return T;
 734       end if;
 735
 736       Disc := First_Discriminant (T);
 737
 738       if No (Discriminant_Default_Value (Disc)) then
 739          return T;
 740       end if;
 741
 742       declare
 743          Act         : constant Entity_Id := Make_Temporary (Loc, 'S');
 744          Constraints : constant List_Id := New_List;
 745          Decl        : Node_Id;
 746
 747       begin
 748          while Present (Disc) loop
 749             Append_To (Constraints,
 750               New_Copy_Tree (Discriminant_Default_Value (Disc)));
 751             Next_Discriminant (Disc);
 752          end loop;
 753
 754          Decl :=
 755            Make_Subtype_Declaration (Loc,
 756              Defining_Identifier => Act,
 757              Subtype_Indication =>
 758                Make_Subtype_Indication (Loc,
 759                  Subtype_Mark => New_Occurrence_Of (T, Loc),
 760                  Constraint =>
 761                    Make_Index_Or_Discriminant_Constraint (Loc,
 762                      Constraints => Constraints)));
 763
 764          Insert_Action (N, Decl);
 765          Analyze (Decl);
 766          return Act;
 767       end;
 768    end Build_Default_Subtype;
 769
 770    --------------------------------------------
 771    -- Build_Discriminal_Subtype_Of_Component --
 772    --------------------------------------------
 773
 774    function Build_Discriminal_Subtype_Of_Component
 775      (T : Entity_Id) return Node_Id
 776    is
 777       Loc : constant Source_Ptr := Sloc (T);
 778       D   : Elmt_Id;
 779       Id  : Node_Id;
 780
 781       function Build_Discriminal_Array_Constraint return List_Id;
 782       --  If one or more of the bounds of the component depends on
 783       --  discriminants, build  actual constraint using the discriminants
 784       --  of the prefix.
 785
 786       function Build_Discriminal_Record_Constraint return List_Id;
 787       --  Similar to previous one, for discriminated components constrained
 788       --  by the discriminant of the enclosing object.
 789
 790       ----------------------------------------
 791       -- Build_Discriminal_Array_Constraint --
 792       ----------------------------------------
 793
 794       function Build_Discriminal_Array_Constraint return List_Id is
 795          Constraints : constant List_Id := New_List;
 796          Indx        : Node_Id;
 797          Hi          : Node_Id;
 798          Lo          : Node_Id;
 799          Old_Hi      : Node_Id;
 800          Old_Lo      : Node_Id;
 801
 802       begin
 803          Indx := First_Index (T);
 804          while Present (Indx) loop
 805             Old_Lo := Type_Low_Bound  (Etype (Indx));
 806             Old_Hi := Type_High_Bound (Etype (Indx));
 807
 808             if Denotes_Discriminant (Old_Lo) then
 809                Lo := New_Occurrence_Of (Discriminal (Entity (Old_Lo)), Loc);
 810
 811             else
 812                Lo := New_Copy_Tree (Old_Lo);
 813             end if;
 814
 815             if Denotes_Discriminant (Old_Hi) then
 816                Hi := New_Occurrence_Of (Discriminal (Entity (Old_Hi)), Loc);
 817
 818             else
 819                Hi := New_Copy_Tree (Old_Hi);
 820             end if;
 821
 822             Append (Make_Range (Loc, Lo, Hi), Constraints);
 823             Next_Index (Indx);
 824          end loop;
 825
 826          return Constraints;
 827       end Build_Discriminal_Array_Constraint;
 828
 829       -----------------------------------------
 830       -- Build_Discriminal_Record_Constraint --
 831       -----------------------------------------
 832
 833       function Build_Discriminal_Record_Constraint return List_Id is
 834          Constraints : constant List_Id := New_List;
 835          D           : Elmt_Id;
 836          D_Val       : Node_Id;
 837
 838       begin
 839          D := First_Elmt (Discriminant_Constraint (T));
 840          while Present (D) loop
 841             if Denotes_Discriminant (Node (D)) then
 842                D_Val :=
 843                  New_Occurrence_Of (Discriminal (Entity (Node (D))), Loc);
 844
 845             else
 846                D_Val := New_Copy_Tree (Node (D));
 847             end if;
 848
 849             Append (D_Val, Constraints);
 850             Next_Elmt (D);
 851          end loop;
 852
 853          return Constraints;
 854       end Build_Discriminal_Record_Constraint;
 855
 856    --  Start of processing for Build_Discriminal_Subtype_Of_Component
 857
 858    begin
 859       if Ekind (T) = E_Array_Subtype then
 860          Id := First_Index (T);
 861          while Present (Id) loop
 862             if Denotes_Discriminant (Type_Low_Bound  (Etype (Id))) or else
 863                Denotes_Discriminant (Type_High_Bound (Etype (Id)))
 864             then
 865                return Build_Component_Subtype
 866                  (Build_Discriminal_Array_Constraint, Loc, T);
 867             end if;
 868
 869             Next_Index (Id);
 870          end loop;
 871
 872       elsif Ekind (T) = E_Record_Subtype
 873         and then Has_Discriminants (T)
 874         and then not Has_Unknown_Discriminants (T)
 875       then
 876          D := First_Elmt (Discriminant_Constraint (T));
 877          while Present (D) loop
 878             if Denotes_Discriminant (Node (D)) then
 879                return Build_Component_Subtype
 880                  (Build_Discriminal_Record_Constraint, Loc, T);
 881             end if;
 882
 883             Next_Elmt (D);
 884          end loop;
 885       end if;
 886
 887       --  If none of the above, the actual and nominal subtypes are the same
 888
 889       return Empty;
 890    end Build_Discriminal_Subtype_Of_Component;
 891
 892    ------------------------------
 893    -- Build_Elaboration_Entity --
 894    ------------------------------
 895
 896    procedure Build_Elaboration_Entity (N : Node_Id; Spec_Id : Entity_Id) is
 897       Loc      : constant Source_Ptr := Sloc (N);
 898       Decl     : Node_Id;
 899       Elab_Ent : Entity_Id;
 900
 901       procedure Set_Package_Name (Ent : Entity_Id);
 902       --  Given an entity, sets the fully qualified name of the entity in
 903       --  Name_Buffer, with components separated by double underscores. This
 904       --  is a recursive routine that climbs the scope chain to Standard.
 905
 906       ----------------------
 907       -- Set_Package_Name --
 908       ----------------------
 909
 910       procedure Set_Package_Name (Ent : Entity_Id) is
 911       begin
 912          if Scope (Ent) /= Standard_Standard then
 913             Set_Package_Name (Scope (Ent));
 914
 915             declare
 916                Nam : constant String := Get_Name_String (Chars (Ent));
 917             begin
 918                Name_Buffer (Name_Len + 1) := '_';
 919                Name_Buffer (Name_Len + 2) := '_';
 920                Name_Buffer (Name_Len + 3 .. Name_Len + Nam'Length + 2) := Nam;
 921                Name_Len := Name_Len + Nam'Length + 2;
 922             end;
 923
 924          else
 925             Get_Name_String (Chars (Ent));
 926          end if;
 927       end Set_Package_Name;
 928
 929    --  Start of processing for Build_Elaboration_Entity
 930
 931    begin
 932       --  Ignore if already constructed
 933
 934       if Present (Elaboration_Entity (Spec_Id)) then
 935          return;
 936       end if;
 937
 938       --  Construct name of elaboration entity as xxx_E, where xxx is the unit
 939       --  name with dots replaced by double underscore. We have to manually
 940       --  construct this name, since it will be elaborated in the outer scope,
 941       --  and thus will not have the unit name automatically prepended.
 942
 943       Set_Package_Name (Spec_Id);
 944
 945       --  Append _E
 946
 947       Name_Buffer (Name_Len + 1) := '_';
 948       Name_Buffer (Name_Len + 2) := 'E';
 949       Name_Len := Name_Len + 2;
 950
 951       --  Create elaboration flag
 952
 953       Elab_Ent :=
 954         Make_Defining_Identifier (Loc, Chars => Name_Find);
 955       Set_Elaboration_Entity (Spec_Id, Elab_Ent);
 956
 957       Decl :=
 958          Make_Object_Declaration (Loc,
 959            Defining_Identifier => Elab_Ent,
 960            Object_Definition   =>
 961              New_Occurrence_Of (Standard_Boolean, Loc),
 962            Expression          =>
 963              New_Occurrence_Of (Standard_False, Loc));
 964
 965       Push_Scope (Standard_Standard);
 966       Add_Global_Declaration (Decl);
 967       Pop_Scope;
 968
 969       --  Reset True_Constant indication, since we will indeed assign a value
 970       --  to the variable in the binder main. We also kill the Current_Value
 971       --  and Last_Assignment fields for the same reason.
 972
 973       Set_Is_True_Constant (Elab_Ent, False);
 974       Set_Current_Value    (Elab_Ent, Empty);
 975       Set_Last_Assignment  (Elab_Ent, Empty);
 976
 977       --  We do not want any further qualification of the name (if we did
 978       --  not do this, we would pick up the name of the generic package
 979       --  in the case of a library level generic instantiation).
 980
 981       Set_Has_Qualified_Name       (Elab_Ent);
 982       Set_Has_Fully_Qualified_Name (Elab_Ent);
 983    end Build_Elaboration_Entity;
 984
 985    -----------------------------------
 986    -- Cannot_Raise_Constraint_Error --
 987    -----------------------------------
 988
 989    function Cannot_Raise_Constraint_Error (Expr : Node_Id) return Boolean is
 990    begin
 991       if Compile_Time_Known_Value (Expr) then
 992          return True;
 993
 994       elsif Do_Range_Check (Expr) then
 995          return False;
 996
 997       elsif Raises_Constraint_Error (Expr) then
 998          return False;
 999
1000       else
1001          case Nkind (Expr) is
1002             when N_Identifier =>
1003                return True;
1004
1005             when N_Expanded_Name =>
1006                return True;
1007
1008             when N_Selected_Component =>
1009                return not Do_Discriminant_Check (Expr);
1010
1011             when N_Attribute_Reference =>
1012                if Do_Overflow_Check (Expr) then
1013                   return False;
1014
1015                elsif No (Expressions (Expr)) then
1016                   return True;
1017
1018                else
1019                   declare
1020                      N : Node_Id;
1021
1022                   begin
1023                      N := First (Expressions (Expr));
1024                      while Present (N) loop
1025                         if Cannot_Raise_Constraint_Error (N) then
1026                            Next (N);
1027                         else
1028                            return False;
1029                         end if;
1030                      end loop;
1031
1032                      return True;
1033                   end;
1034                end if;
1035
1036             when N_Type_Conversion =>
1037                if Do_Overflow_Check (Expr)
1038                  or else Do_Length_Check (Expr)
1039                  or else Do_Tag_Check (Expr)
1040                then
1041                   return False;
1042                else
1043                   return
1044                     Cannot_Raise_Constraint_Error (Expression (Expr));
1045                end if;
1046
1047             when N_Unchecked_Type_Conversion =>
1048                return Cannot_Raise_Constraint_Error (Expression (Expr));
1049
1050             when N_Unary_Op =>
1051                if Do_Overflow_Check (Expr) then
1052                   return False;
1053                else
1054                   return
1055                     Cannot_Raise_Constraint_Error (Right_Opnd (Expr));
1056                end if;
1057
1058             when N_Op_Divide |
1059                  N_Op_Mod    |
1060                  N_Op_Rem
1061             =>
1062                if Do_Division_Check (Expr)
1063                  or else Do_Overflow_Check (Expr)
1064                then
1065                   return False;
1066                else
1067                   return
1068                     Cannot_Raise_Constraint_Error (Left_Opnd (Expr))
1069                       and then
1070                     Cannot_Raise_Constraint_Error (Right_Opnd (Expr));
1071                end if;
1072
1073             when N_Op_Add                    |
1074                  N_Op_And                    |
1075                  N_Op_Concat                 |
1076                  N_Op_Eq                     |
1077                  N_Op_Expon                  |
1078                  N_Op_Ge                     |
1079                  N_Op_Gt                     |
1080                  N_Op_Le                     |
1081                  N_Op_Lt                     |
1082                  N_Op_Multiply               |
1083                  N_Op_Ne                     |
1084                  N_Op_Or                     |
1085                  N_Op_Rotate_Left            |
1086                  N_Op_Rotate_Right           |
1087                  N_Op_Shift_Left             |
1088                  N_Op_Shift_Right            |
1089                  N_Op_Shift_Right_Arithmetic |
1090                  N_Op_Subtract               |
1091                  N_Op_Xor
1092             =>
1093                if Do_Overflow_Check (Expr) then
1094                   return False;
1095                else
1096                   return
1097                     Cannot_Raise_Constraint_Error (Left_Opnd (Expr))
1098                       and then
1099                     Cannot_Raise_Constraint_Error (Right_Opnd (Expr));
1100                end if;
1101
1102             when others =>
1103                return False;
1104          end case;
1105       end if;
1106    end Cannot_Raise_Constraint_Error;
1107
1108    ---------------------------------------
1109    -- Check_Later_Vs_Basic_Declarations --
1110    ---------------------------------------
1111
1112    procedure Check_Later_Vs_Basic_Declarations
1113      (Decls          : List_Id;
1114       During_Parsing : Boolean)
1115    is
1116       Body_Sloc : Source_Ptr;
1117       Decl      : Node_Id;
1118
1119       function Is_Later_Declarative_Item (Decl : Node_Id) return Boolean;
1120       --  Return whether Decl is considered as a declarative item.
1121       --  When During_Parsing is True, the semantics of Ada 83 is followed.
1122       --  When During_Parsing is False, the semantics of SPARK is followed.
1123
1124       -------------------------------
1125       -- Is_Later_Declarative_Item --
1126       -------------------------------
1127
1128       function Is_Later_Declarative_Item (Decl : Node_Id) return Boolean is
1129       begin
1130          if Nkind (Decl) in N_Later_Decl_Item then
1131             return True;
1132
1133          elsif Nkind (Decl) = N_Pragma then
1134             return True;
1135
1136          elsif During_Parsing then
1137             return False;
1138
1139          --  In SPARK, a package declaration is not considered as a later
1140          --  declarative item.
1141
1142          elsif Nkind (Decl) = N_Package_Declaration then
1143             return False;
1144
1145          --  In SPARK, a renaming is considered as a later declarative item
1146
1147          elsif Nkind (Decl) in N_Renaming_Declaration then
1148             return True;
1149
1150          else
1151             return False;
1152          end if;
1153       end Is_Later_Declarative_Item;
1154
1155    --  Start of Check_Later_Vs_Basic_Declarations
1156
1157    begin
1158       Decl := First (Decls);
1159
1160       --  Loop through sequence of basic declarative items
1161
1162       Outer : while Present (Decl) loop
1163          if Nkind (Decl) /= N_Subprogram_Body
1164            and then Nkind (Decl) /= N_Package_Body
1165            and then Nkind (Decl) /= N_Task_Body
1166            and then Nkind (Decl) not in N_Body_Stub
1167          then
1168             Next (Decl);
1169
1170             --  Once a body is encountered, we only allow later declarative
1171             --  items. The inner loop checks the rest of the list.
1172
1173          else
1174             Body_Sloc := Sloc (Decl);
1175
1176             Inner : while Present (Decl) loop
1177                if not Is_Later_Declarative_Item (Decl) then
1178                   if During_Parsing then
1179                      if Ada_Version = Ada_83 then
1180                         Error_Msg_Sloc := Body_Sloc;
1181                         Error_Msg_N
1182                           ("(Ada 83) decl cannot appear after body#", Decl);
1183                      end if;
1184                   else
1185                      Error_Msg_Sloc := Body_Sloc;
1186                      Check_SPARK_Restriction
1187                        ("decl cannot appear after body#", Decl);
1188                   end if;
1189                end if;
1190
1191                Next (Decl);
1192             end loop Inner;
1193          end if;
1194       end loop Outer;
1195    end Check_Later_Vs_Basic_Declarations;
1196
1197    -----------------------------------------
1198    -- Check_Dynamically_Tagged_Expression --
1199    -----------------------------------------
1200
1201    procedure Check_Dynamically_Tagged_Expression
1202      (Expr        : Node_Id;
1203       Typ         : Entity_Id;
1204       Related_Nod : Node_Id)
1205    is
1206    begin
1207       pragma Assert (Is_Tagged_Type (Typ));
1208
1209       --  In order to avoid spurious errors when analyzing the expanded code,
1210       --  this check is done only for nodes that come from source and for
1211       --  actuals of generic instantiations.
1212
1213       if (Comes_From_Source (Related_Nod)
1214            or else In_Generic_Actual (Expr))
1215         and then (Is_Class_Wide_Type (Etype (Expr))
1216                    or else Is_Dynamically_Tagged (Expr))
1217         and then Is_Tagged_Type (Typ)
1218         and then not Is_Class_Wide_Type (Typ)
1219       then
1220          Error_Msg_N ("dynamically tagged expression not allowed!", Expr);
1221       end if;
1222    end Check_Dynamically_Tagged_Expression;
1223
1224    --------------------------
1225    -- Check_Fully_Declared --
1226    --------------------------
1227
1228    procedure Check_Fully_Declared (T : Entity_Id; N : Node_Id) is
1229    begin
1230       if Ekind (T) = E_Incomplete_Type then
1231
1232          --  Ada 2005 (AI-50217): If the type is available through a limited
1233          --  with_clause, verify that its full view has been analyzed.
1234
1235          if From_With_Type (T)
1236            and then Present (Non_Limited_View (T))
1237            and then Ekind (Non_Limited_View (T)) /= E_Incomplete_Type
1238          then
1239             --  The non-limited view is fully declared
1240             null;
1241
1242          else
1243             Error_Msg_NE
1244               ("premature usage of incomplete}", N, First_Subtype (T));
1245          end if;
1246
1247       --  Need comments for these tests ???
1248
1249       elsif Has_Private_Component (T)
1250         and then not Is_Generic_Type (Root_Type (T))
1251         and then not In_Spec_Expression
1252       then
1253          --  Special case: if T is the anonymous type created for a single
1254          --  task or protected object, use the name of the source object.
1255
1256          if Is_Concurrent_Type (T)
1257            and then not Comes_From_Source (T)
1258            and then Nkind (N) = N_Object_Declaration
1259          then
1260             Error_Msg_NE ("type of& has incomplete component", N,
1261               Defining_Identifier (N));
1262
1263          else
1264             Error_Msg_NE
1265               ("premature usage of incomplete}", N, First_Subtype (T));
1266          end if;
1267       end if;
1268    end Check_Fully_Declared;
1269
1270    -------------------------
1271    -- Check_Nested_Access --
1272    -------------------------
1273
1274    procedure Check_Nested_Access (Ent : Entity_Id) is
1275       Scop         : constant Entity_Id := Current_Scope;
1276       Current_Subp : Entity_Id;
1277       Enclosing    : Entity_Id;
1278
1279    begin
1280       --  Currently only enabled for VM back-ends for efficiency, should we
1281       --  enable it more systematically ???
1282
1283       --  Check for Is_Imported needs commenting below ???
1284
1285       if VM_Target /= No_VM
1286         and then (Ekind (Ent) = E_Variable
1287                     or else
1288                   Ekind (Ent) = E_Constant
1289                     or else
1290                   Ekind (Ent) = E_Loop_Parameter)
1291         and then Scope (Ent) /= Empty
1292         and then not Is_Library_Level_Entity (Ent)
1293         and then not Is_Imported (Ent)
1294       then
1295          if Is_Subprogram (Scop)
1296            or else Is_Generic_Subprogram (Scop)
1297            or else Is_Entry (Scop)
1298          then
1299             Current_Subp := Scop;
1300          else
1301             Current_Subp := Current_Subprogram;
1302          end if;
1303
1304          Enclosing := Enclosing_Subprogram (Ent);
1305
1306          if Enclosing /= Empty
1307            and then Enclosing /= Current_Subp
1308          then
1309             Set_Has_Up_Level_Access (Ent, True);
1310          end if;
1311       end if;
1312    end Check_Nested_Access;
1313
1314    ----------------------------
1315    -- Check_Order_Dependence --
1316    ----------------------------
1317
1318    procedure Check_Order_Dependence is
1319       Act1 : Node_Id;
1320       Act2 : Node_Id;
1321
1322    begin
1323       if Ada_Version < Ada_2012 then
1324          return;
1325       end if;
1326
1327       --  Ada 2012 AI04-0144-2: Dangerous order dependence. Actuals in nested
1328       --  calls within a construct have been collected. If one of them is
1329       --  writable and overlaps with another one, evaluation of the enclosing
1330       --  construct is nondeterministic. This is illegal in Ada 2012, but is
1331       --  treated as a warning for now.
1332
1333       for J in 1 .. Actuals_In_Call.Last loop
1334          if Actuals_In_Call.Table (J).Is_Writable then
1335             Act1 := Actuals_In_Call.Table (J).Act;
1336
1337             if Nkind (Act1) = N_Attribute_Reference then
1338                Act1 := Prefix (Act1);
1339             end if;
1340
1341             for K in 1 .. Actuals_In_Call.Last loop
1342                if K /= J then
1343                   Act2 := Actuals_In_Call.Table (K).Act;
1344
1345                   if Nkind (Act2) = N_Attribute_Reference then
1346                      Act2 := Prefix (Act2);
1347                   end if;
1348
1349                   if Actuals_In_Call.Table (K).Is_Writable
1350                     and then K < J
1351                   then
1352                      --  Already checked
1353
1354                      null;
1355
1356                   elsif Denotes_Same_Object (Act1, Act2)
1357                     and then Parent (Act1) /= Parent (Act2)
1358                   then
1359                      Error_Msg_N
1360                        ("result may differ if evaluated "
1361                         & "after other actual in expression?", Act1);
1362                   end if;
1363                end if;
1364             end loop;
1365          end if;
1366       end loop;
1367
1368       --  Remove checked actuals from table
1369
1370       Actuals_In_Call.Set_Last (0);
1371    end Check_Order_Dependence;
1372
1373    ------------------------------------------
1374    -- Check_Potentially_Blocking_Operation --
1375    ------------------------------------------
1376
1377    procedure Check_Potentially_Blocking_Operation (N : Node_Id) is
1378       S : Entity_Id;
1379
1380    begin
1381       --  N is one of the potentially blocking operations listed in 9.5.1(8).
1382       --  When pragma Detect_Blocking is active, the run time will raise
1383       --  Program_Error. Here we only issue a warning, since we generally
1384       --  support the use of potentially blocking operations in the absence
1385       --  of the pragma.
1386
1387       --  Indirect blocking through a subprogram call cannot be diagnosed
1388       --  statically without interprocedural analysis, so we do not attempt
1389       --  to do it here.
1390
1391       S := Scope (Current_Scope);
1392       while Present (S) and then S /= Standard_Standard loop
1393          if Is_Protected_Type (S) then
1394             Error_Msg_N
1395               ("potentially blocking operation in protected operation?", N);
1396             return;
1397          end if;
1398
1399          S := Scope (S);
1400       end loop;
1401    end Check_Potentially_Blocking_Operation;
1402
1403    ------------------------------
1404    -- Check_Unprotected_Access --
1405    ------------------------------
1406
1407    procedure Check_Unprotected_Access
1408      (Context : Node_Id;
1409       Expr    : Node_Id)
1410    is
1411       Cont_Encl_Typ : Entity_Id;
1412       Pref_Encl_Typ : Entity_Id;
1413
1414       function Enclosing_Protected_Type (Obj : Node_Id) return Entity_Id;
1415       --  Check whether Obj is a private component of a protected object.
1416       --  Return the protected type where the component resides, Empty
1417       --  otherwise.
1418
1419       function Is_Public_Operation return Boolean;
1420       --  Verify that the enclosing operation is callable from outside the
1421       --  protected object, to minimize false positives.
1422
1423       ------------------------------
1424       -- Enclosing_Protected_Type --
1425       ------------------------------
1426
1427       function Enclosing_Protected_Type (Obj : Node_Id) return Entity_Id is
1428       begin
1429          if Is_Entity_Name (Obj) then
1430             declare
1431                Ent : Entity_Id := Entity (Obj);
1432
1433             begin
1434                --  The object can be a renaming of a private component, use
1435                --  the original record component.
1436
1437                if Is_Prival (Ent) then
1438                   Ent := Prival_Link (Ent);
1439                end if;
1440
1441                if Is_Protected_Type (Scope (Ent)) then
1442                   return Scope (Ent);
1443                end if;
1444             end;
1445          end if;
1446
1447          --  For indexed and selected components, recursively check the prefix
1448
1449          if Nkind_In (Obj, N_Indexed_Component, N_Selected_Component) then
1450             return Enclosing_Protected_Type (Prefix (Obj));
1451
1452          --  The object does not denote a protected component
1453
1454          else
1455             return Empty;
1456          end if;
1457       end Enclosing_Protected_Type;
1458
1459       -------------------------
1460       -- Is_Public_Operation --
1461       -------------------------
1462
1463       function Is_Public_Operation return Boolean is
1464          S : Entity_Id;
1465          E : Entity_Id;
1466
1467       begin
1468          S := Current_Scope;
1469          while Present (S)
1470            and then S /= Pref_Encl_Typ
1471          loop
1472             if Scope (S) = Pref_Encl_Typ then
1473                E := First_Entity (Pref_Encl_Typ);
1474                while Present (E)
1475                  and then E /= First_Private_Entity (Pref_Encl_Typ)
1476                loop
1477                   if E = S then
1478                      return True;
1479                   end if;
1480                   Next_Entity (E);
1481                end loop;
1482             end if;
1483
1484             S := Scope (S);
1485          end loop;
1486
1487          return False;
1488       end Is_Public_Operation;
1489
1490    --  Start of processing for Check_Unprotected_Access
1491
1492    begin
1493       if Nkind (Expr) = N_Attribute_Reference
1494         and then Attribute_Name (Expr) = Name_Unchecked_Access
1495       then
1496          Cont_Encl_Typ := Enclosing_Protected_Type (Context);
1497          Pref_Encl_Typ := Enclosing_Protected_Type (Prefix (Expr));
1498
1499          --  Check whether we are trying to export a protected component to a
1500          --  context with an equal or lower access level.
1501
1502          if Present (Pref_Encl_Typ)
1503            and then No (Cont_Encl_Typ)
1504            and then Is_Public_Operation
1505            and then Scope_Depth (Pref_Encl_Typ) >=
1506                       Object_Access_Level (Context)
1507          then
1508             Error_Msg_N
1509               ("?possible unprotected access to protected data", Expr);
1510          end if;
1511       end if;
1512    end Check_Unprotected_Access;
1513
1514    ---------------
1515    -- Check_VMS --
1516    ---------------
1517
1518    procedure Check_VMS (Construct : Node_Id) is
1519    begin
1520       if not OpenVMS_On_Target then
1521          Error_Msg_N
1522            ("this construct is allowed only in Open'V'M'S", Construct);
1523       end if;
1524    end Check_VMS;
1525
1526    ------------------------
1527    -- Collect_Interfaces --
1528    ------------------------
1529
1530    procedure Collect_Interfaces
1531      (T               : Entity_Id;
1532       Ifaces_List     : out Elist_Id;
1533       Exclude_Parents : Boolean := False;
1534       Use_Full_View   : Boolean := True)
1535    is
1536       procedure Collect (Typ : Entity_Id);
1537       --  Subsidiary subprogram used to traverse the whole list
1538       --  of directly and indirectly implemented interfaces
1539
1540       -------------
1541       -- Collect --
1542       -------------
1543
1544       procedure Collect (Typ : Entity_Id) is
1545          Ancestor   : Entity_Id;
1546          Full_T     : Entity_Id;
1547          Id         : Node_Id;
1548          Iface      : Entity_Id;
1549
1550       begin
1551          Full_T := Typ;
1552
1553          --  Handle private types
1554
1555          if Use_Full_View
1556            and then Is_Private_Type (Typ)
1557            and then Present (Full_View (Typ))
1558          then
1559             Full_T := Full_View (Typ);
1560          end if;
1561
1562          --  Include the ancestor if we are generating the whole list of
1563          --  abstract interfaces.
1564
1565          if Etype (Full_T) /= Typ
1566
1567             --  Protect the frontend against wrong sources. For example:
1568
1569             --    package P is
1570             --      type A is tagged null record;
1571             --      type B is new A with private;
1572             --      type C is new A with private;
1573             --    private
1574             --      type B is new C with null record;
1575             --      type C is new B with null record;
1576             --    end P;
1577
1578            and then Etype (Full_T) /= T
1579          then
1580             Ancestor := Etype (Full_T);
1581             Collect (Ancestor);
1582
1583             if Is_Interface (Ancestor)
1584               and then not Exclude_Parents
1585             then
1586                Append_Unique_Elmt (Ancestor, Ifaces_List);
1587             end if;
1588          end if;
1589
1590          --  Traverse the graph of ancestor interfaces
1591
1592          if Is_Non_Empty_List (Abstract_Interface_List (Full_T)) then
1593             Id := First (Abstract_Interface_List (Full_T));
1594             while Present (Id) loop
1595                Iface := Etype (Id);
1596
1597                --  Protect against wrong uses. For example:
1598                --    type I is interface;
1599                --    type O is tagged null record;
1600                --    type Wrong is new I and O with null record; -- ERROR
1601
1602                if Is_Interface (Iface) then
1603                   if Exclude_Parents
1604                     and then Etype (T) /= T
1605                     and then Interface_Present_In_Ancestor (Etype (T), Iface)
1606                   then
1607                      null;
1608                   else
1609                      Collect (Iface);
1610                      Append_Unique_Elmt (Iface, Ifaces_List);
1611                   end if;
1612                end if;
1613
1614                Next (Id);
1615             end loop;
1616          end if;
1617       end Collect;
1618
1619    --  Start of processing for Collect_Interfaces
1620
1621    begin
1622       pragma Assert (Is_Tagged_Type (T) or else Is_Concurrent_Type (T));
1623       Ifaces_List := New_Elmt_List;
1624       Collect (T);
1625    end Collect_Interfaces;
1626
1627    ----------------------------------
1628    -- Collect_Interface_Components --
1629    ----------------------------------
1630
1631    procedure Collect_Interface_Components
1632      (Tagged_Type     : Entity_Id;
1633       Components_List : out Elist_Id)
1634    is
1635       procedure Collect (Typ : Entity_Id);
1636       --  Subsidiary subprogram used to climb to the parents
1637
1638       -------------
1639       -- Collect --
1640       -------------
1641
1642       procedure Collect (Typ : Entity_Id) is
1643          Tag_Comp   : Entity_Id;
1644          Parent_Typ : Entity_Id;
1645
1646       begin
1647          --  Handle private types
1648
1649          if Present (Full_View (Etype (Typ))) then
1650             Parent_Typ := Full_View (Etype (Typ));
1651          else
1652             Parent_Typ := Etype (Typ);
1653          end if;
1654
1655          if Parent_Typ /= Typ
1656
1657             --  Protect the frontend against wrong sources. For example:
1658
1659             --    package P is
1660             --      type A is tagged null record;
1661             --      type B is new A with private;
1662             --      type C is new A with private;
1663             --    private
1664             --      type B is new C with null record;
1665             --      type C is new B with null record;
1666             --    end P;
1667
1668            and then Parent_Typ /= Tagged_Type
1669          then
1670             Collect (Parent_Typ);
1671          end if;
1672
1673          --  Collect the components containing tags of secondary dispatch
1674          --  tables.
1675
1676          Tag_Comp := Next_Tag_Component (First_Tag_Component (Typ));
1677          while Present (Tag_Comp) loop
1678             pragma Assert (Present (Related_Type (Tag_Comp)));
1679             Append_Elmt (Tag_Comp, Components_List);
1680
1681             Tag_Comp := Next_Tag_Component (Tag_Comp);
1682          end loop;
1683       end Collect;
1684
1685    --  Start of processing for Collect_Interface_Components
1686
1687    begin
1688       pragma Assert (Ekind (Tagged_Type) = E_Record_Type
1689         and then Is_Tagged_Type (Tagged_Type));
1690
1691       Components_List := New_Elmt_List;
1692       Collect (Tagged_Type);
1693    end Collect_Interface_Components;
1694
1695    -----------------------------
1696    -- Collect_Interfaces_Info --
1697    -----------------------------
1698
1699    procedure Collect_Interfaces_Info
1700      (T               : Entity_Id;
1701       Ifaces_List     : out Elist_Id;
1702       Components_List : out Elist_Id;
1703       Tags_List       : out Elist_Id)
1704    is
1705       Comps_List : Elist_Id;
1706       Comp_Elmt  : Elmt_Id;
1707       Comp_Iface : Entity_Id;
1708       Iface_Elmt : Elmt_Id;
1709       Iface      : Entity_Id;
1710
1711       function Search_Tag (Iface : Entity_Id) return Entity_Id;
1712       --  Search for the secondary tag associated with the interface type
1713       --  Iface that is implemented by T.
1714
1715       ----------------
1716       -- Search_Tag --
1717       ----------------
1718
1719       function Search_Tag (Iface : Entity_Id) return Entity_Id is
1720          ADT : Elmt_Id;
1721       begin
1722          if not Is_CPP_Class (T) then
1723             ADT := Next_Elmt (Next_Elmt (First_Elmt (Access_Disp_Table (T))));
1724          else
1725             ADT := Next_Elmt (First_Elmt (Access_Disp_Table (T)));
1726          end if;
1727
1728          while Present (ADT)
1729             and then Is_Tag (Node (ADT))
1730             and then Related_Type (Node (ADT)) /= Iface
1731          loop
1732             --  Skip secondary dispatch table referencing thunks to user
1733             --  defined primitives covered by this interface.
1734
1735             pragma Assert (Has_Suffix (Node (ADT), 'P'));
1736             Next_Elmt (ADT);
1737
1738             --  Skip secondary dispatch tables of Ada types
1739
1740             if not Is_CPP_Class (T) then
1741
1742                --  Skip secondary dispatch table referencing thunks to
1743                --  predefined primitives.
1744
1745                pragma Assert (Has_Suffix (Node (ADT), 'Y'));
1746                Next_Elmt (ADT);
1747
1748                --  Skip secondary dispatch table referencing user-defined
1749                --  primitives covered by this interface.
1750
1751                pragma Assert (Has_Suffix (Node (ADT), 'D'));
1752                Next_Elmt (ADT);
1753
1754                --  Skip secondary dispatch table referencing predefined
1755                --  primitives.
1756
1757                pragma Assert (Has_Suffix (Node (ADT), 'Z'));
1758                Next_Elmt (ADT);
1759             end if;
1760          end loop;
1761
1762          pragma Assert (Is_Tag (Node (ADT)));
1763          return Node (ADT);
1764       end Search_Tag;
1765
1766    --  Start of processing for Collect_Interfaces_Info
1767
1768    begin
1769       Collect_Interfaces (T, Ifaces_List);
1770       Collect_Interface_Components (T, Comps_List);
1771
1772       --  Search for the record component and tag associated with each
1773       --  interface type of T.
1774
1775       Components_List := New_Elmt_List;
1776       Tags_List       := New_Elmt_List;
1777
1778       Iface_Elmt := First_Elmt (Ifaces_List);
1779       while Present (Iface_Elmt) loop
1780          Iface := Node (Iface_Elmt);
1781
1782          --  Associate the primary tag component and the primary dispatch table
1783          --  with all the interfaces that are parents of T
1784
1785          if Is_Ancestor (Iface, T, Use_Full_View => True) then
1786             Append_Elmt (First_Tag_Component (T), Components_List);
1787             Append_Elmt (Node (First_Elmt (Access_Disp_Table (T))), Tags_List);
1788
1789          --  Otherwise search for the tag component and secondary dispatch
1790          --  table of Iface
1791
1792          else
1793             Comp_Elmt := First_Elmt (Comps_List);
1794             while Present (Comp_Elmt) loop
1795                Comp_Iface := Related_Type (Node (Comp_Elmt));
1796
1797                if Comp_Iface = Iface
1798                  or else Is_Ancestor (Iface, Comp_Iface, Use_Full_View => True)
1799                then
1800                   Append_Elmt (Node (Comp_Elmt), Components_List);
1801                   Append_Elmt (Search_Tag (Comp_Iface), Tags_List);
1802                   exit;
1803                end if;
1804
1805                Next_Elmt (Comp_Elmt);
1806             end loop;
1807             pragma Assert (Present (Comp_Elmt));
1808          end if;
1809
1810          Next_Elmt (Iface_Elmt);
1811       end loop;
1812    end Collect_Interfaces_Info;
1813
1814    ---------------------
1815    -- Collect_Parents --
1816    ---------------------
1817
1818    procedure Collect_Parents
1819      (T             : Entity_Id;
1820       List          : out Elist_Id;
1821       Use_Full_View : Boolean := True)
1822    is
1823       Current_Typ : Entity_Id := T;
1824       Parent_Typ  : Entity_Id;
1825
1826    begin
1827       List := New_Elmt_List;
1828
1829       --  No action if the if the type has no parents
1830
1831       if T = Etype (T) then
1832          return;
1833       end if;
1834
1835       loop
1836          Parent_Typ := Etype (Current_Typ);
1837
1838          if Is_Private_Type (Parent_Typ)
1839            and then Present (Full_View (Parent_Typ))
1840            and then Use_Full_View
1841          then
1842             Parent_Typ := Full_View (Base_Type (Parent_Typ));
1843          end if;
1844
1845          Append_Elmt (Parent_Typ, List);
1846
1847          exit when Parent_Typ = Current_Typ;
1848          Current_Typ := Parent_Typ;
1849       end loop;
1850    end Collect_Parents;
1851
1852    ----------------------------------
1853    -- Collect_Primitive_Operations --
1854    ----------------------------------
1855
1856    function Collect_Primitive_Operations (T : Entity_Id) return Elist_Id is
1857       B_Type         : constant Entity_Id := Base_Type (T);
1858       B_Decl         : constant Node_Id   := Original_Node (Parent (B_Type));
1859       B_Scope        : Entity_Id          := Scope (B_Type);
1860       Op_List        : Elist_Id;
1861       Formal         : Entity_Id;
1862       Is_Prim        : Boolean;
1863       Formal_Derived : Boolean := False;
1864       Id             : Entity_Id;
1865
1866       function Match (E : Entity_Id) return Boolean;
1867       --  True if E's base type is B_Type, or E is of an anonymous access type
1868       --  and the base type of its designated type is B_Type.
1869
1870       -----------
1871       -- Match --
1872       -----------
1873
1874       function Match (E : Entity_Id) return Boolean is
1875          Etyp : Entity_Id := Etype (E);
1876
1877       begin
1878          if Ekind (Etyp) = E_Anonymous_Access_Type then
1879             Etyp := Designated_Type (Etyp);
1880          end if;
1881
1882          return Base_Type (Etyp) = B_Type;
1883       end Match;
1884
1885    --  Start of processing for Collect_Primitive_Operations
1886
1887    begin
1888       --  For tagged types, the primitive operations are collected as they
1889       --  are declared, and held in an explicit list which is simply returned.
1890
1891       if Is_Tagged_Type (B_Type) then
1892          return Primitive_Operations (B_Type);
1893
1894       --  An untagged generic type that is a derived type inherits the
1895       --  primitive operations of its parent type. Other formal types only
1896       --  have predefined operators, which are not explicitly represented.
1897
1898       elsif Is_Generic_Type (B_Type) then
1899          if Nkind (B_Decl) = N_Formal_Type_Declaration
1900            and then Nkind (Formal_Type_Definition (B_Decl))
1901              = N_Formal_Derived_Type_Definition
1902          then
1903             Formal_Derived := True;
1904          else
1905             return New_Elmt_List;
1906          end if;
1907       end if;
1908
1909       Op_List := New_Elmt_List;
1910
1911       if B_Scope = Standard_Standard then
1912          if B_Type = Standard_String then
1913             Append_Elmt (Standard_Op_Concat, Op_List);
1914
1915          elsif B_Type = Standard_Wide_String then
1916             Append_Elmt (Standard_Op_Concatw, Op_List);
1917
1918          else
1919             null;
1920          end if;
1921
1922       elsif (Is_Package_Or_Generic_Package (B_Scope)
1923               and then
1924                 Nkind (Parent (Declaration_Node (First_Subtype (T)))) /=
1925                                                             N_Package_Body)
1926         or else Is_Derived_Type (B_Type)
1927       then
1928          --  The primitive operations appear after the base type, except
1929          --  if the derivation happens within the private part of B_Scope
1930          --  and the type is a private type, in which case both the type
1931          --  and some primitive operations may appear before the base
1932          --  type, and the list of candidates starts after the type.
1933
1934          if In_Open_Scopes (B_Scope)
1935            and then Scope (T) = B_Scope
1936            and then In_Private_Part (B_Scope)
1937          then
1938             Id := Next_Entity (T);
1939          else
1940             Id := Next_Entity (B_Type);
1941          end if;
1942
1943          while Present (Id) loop
1944
1945             --  Note that generic formal subprograms are not
1946             --  considered to be primitive operations and thus
1947             --  are never inherited.
1948
1949             if Is_Overloadable (Id)
1950               and then Nkind (Parent (Parent (Id)))
1951                          not in N_Formal_Subprogram_Declaration
1952             then
1953                Is_Prim := False;
1954
1955                if Match (Id) then
1956                   Is_Prim := True;
1957
1958                else
1959                   Formal := First_Formal (Id);
1960                   while Present (Formal) loop
1961                      if Match (Formal) then
1962                         Is_Prim := True;
1963                         exit;
1964                      end if;
1965
1966                      Next_Formal (Formal);
1967                   end loop;
1968                end if;
1969
1970                --  For a formal derived type, the only primitives are the
1971                --  ones inherited from the parent type. Operations appearing
1972                --  in the package declaration are not primitive for it.
1973
1974                if Is_Prim
1975                  and then (not Formal_Derived
1976                             or else Present (Alias (Id)))
1977                then
1978                   --  In the special case of an equality operator aliased to
1979                   --  an overriding dispatching equality belonging to the same
1980                   --  type, we don't include it in the list of primitives.
1981                   --  This avoids inheriting multiple equality operators when
1982                   --  deriving from untagged private types whose full type is
1983                   --  tagged, which can otherwise cause ambiguities. Note that
1984                   --  this should only happen for this kind of untagged parent
1985                   --  type, since normally dispatching operations are inherited
1986                   --  using the type's Primitive_Operations list.
1987
1988                   if Chars (Id) = Name_Op_Eq
1989                     and then Is_Dispatching_Operation (Id)
1990                     and then Present (Alias (Id))
1991                     and then Present (Overridden_Operation (Alias (Id)))
1992                     and then Base_Type (Etype (First_Entity (Id))) =
1993                                Base_Type (Etype (First_Entity (Alias (Id))))
1994                   then
1995                      null;
1996
1997                   --  Include the subprogram in the list of primitives
1998
1999                   else
2000                      Append_Elmt (Id, Op_List);
2001                   end if;
2002                end if;
2003             end if;
2004
2005             Next_Entity (Id);
2006
2007             --  For a type declared in System, some of its operations may
2008             --  appear in the target-specific extension to System.
2009
2010             if No (Id)
2011               and then B_Scope = RTU_Entity (System)
2012               and then Present_System_Aux
2013             then
2014                B_Scope := System_Aux_Id;
2015                Id := First_Entity (System_Aux_Id);
2016             end if;
2017          end loop;
2018       end if;
2019
2020       return Op_List;
2021    end Collect_Primitive_Operations;
2022
2023    -----------------------------------
2024    -- Compile_Time_Constraint_Error --
2025    -----------------------------------
2026
2027    function Compile_Time_Constraint_Error
2028      (N    : Node_Id;
2029       Msg  : String;
2030       Ent  : Entity_Id  := Empty;
2031       Loc  : Source_Ptr := No_Location;
2032       Warn : Boolean    := False) return Node_Id
2033    is
2034       Msgc : String (1 .. Msg'Length + 2);
2035       --  Copy of message, with room for possible ? and ! at end
2036
2037       Msgl : Natural;
2038       Wmsg : Boolean;
2039       P    : Node_Id;
2040       OldP : Node_Id;
2041       Msgs : Boolean;
2042       Eloc : Source_Ptr;
2043
2044    begin
2045       --  A static constraint error in an instance body is not a fatal error.
2046       --  we choose to inhibit the message altogether, because there is no
2047       --  obvious node (for now) on which to post it. On the other hand the
2048       --  offending node must be replaced with a constraint_error in any case.
2049
2050       --  No messages are generated if we already posted an error on this node
2051
2052       if not Error_Posted (N) then
2053          if Loc /= No_Location then
2054             Eloc := Loc;
2055          else
2056             Eloc := Sloc (N);
2057          end if;
2058
2059          Msgc (1 .. Msg'Length) := Msg;
2060          Msgl := Msg'Length;
2061
2062          --  Message is a warning, even in Ada 95 case
2063
2064          if Msg (Msg'Last) = '?' then
2065             Wmsg := True;
2066
2067          --  In Ada 83, all messages are warnings. In the private part and
2068          --  the body of an instance, constraint_checks are only warnings.
2069          --  We also make this a warning if the Warn parameter is set.
2070
2071          elsif Warn
2072            or else (Ada_Version = Ada_83 and then Comes_From_Source (N))
2073          then
2074             Msgl := Msgl + 1;
2075             Msgc (Msgl) := '?';
2076             Wmsg := True;
2077
2078          elsif In_Instance_Not_Visible then
2079             Msgl := Msgl + 1;
2080             Msgc (Msgl) := '?';
2081             Wmsg := True;
2082
2083          --  Otherwise we have a real error message (Ada 95 static case)
2084          --  and we make this an unconditional message. Note that in the
2085          --  warning case we do not make the message unconditional, it seems
2086          --  quite reasonable to delete messages like this (about exceptions
2087          --  that will be raised) in dead code.
2088
2089          else
2090             Wmsg := False;
2091             Msgl := Msgl + 1;
2092             Msgc (Msgl) := '!';
2093          end if;
2094
2095          --  Should we generate a warning? The answer is not quite yes. The
2096          --  very annoying exception occurs in the case of a short circuit
2097          --  operator where the left operand is static and decisive. Climb
2098          --  parents to see if that is the case we have here. Conditional
2099          --  expressions with decisive conditions are a similar situation.
2100
2101          Msgs := True;
2102          P := N;
2103          loop
2104             OldP := P;
2105             P := Parent (P);
2106
2107             --  And then with False as left operand
2108
2109             if Nkind (P) = N_And_Then
2110               and then Compile_Time_Known_Value (Left_Opnd (P))
2111               and then Is_False (Expr_Value (Left_Opnd (P)))
2112             then
2113                Msgs := False;
2114                exit;
2115
2116             --  OR ELSE with True as left operand
2117
2118             elsif Nkind (P) = N_Or_Else
2119               and then Compile_Time_Known_Value (Left_Opnd (P))
2120               and then Is_True (Expr_Value (Left_Opnd (P)))
2121             then
2122                Msgs := False;
2123                exit;
2124
2125             --  Conditional expression
2126
2127             elsif Nkind (P) = N_Conditional_Expression then
2128                declare
2129                   Cond : constant Node_Id := First (Expressions (P));
2130                   Texp : constant Node_Id := Next (Cond);
2131                   Fexp : constant Node_Id := Next (Texp);
2132
2133                begin
2134                   if Compile_Time_Known_Value (Cond) then
2135
2136                      --  Condition is True and we are in the right operand
2137
2138                      if Is_True (Expr_Value (Cond))
2139                        and then OldP = Fexp
2140                      then
2141                         Msgs := False;
2142                         exit;
2143
2144                      --  Condition is False and we are in the left operand
2145
2146                      elsif Is_False (Expr_Value (Cond))
2147                        and then OldP = Texp
2148                      then
2149                         Msgs := False;
2150                         exit;
2151                      end if;
2152                   end if;
2153                end;
2154
2155             --  Special case for component association in aggregates, where
2156             --  we want to keep climbing up to the parent aggregate.
2157
2158             elsif Nkind (P) = N_Component_Association
2159               and then Nkind (Parent (P)) = N_Aggregate
2160             then
2161                null;
2162
2163             --  Keep going if within subexpression
2164
2165             else
2166                exit when Nkind (P) not in N_Subexpr;
2167             end if;
2168          end loop;
2169
2170          if Msgs then
2171             if Present (Ent) then
2172                Error_Msg_NEL (Msgc (1 .. Msgl), N, Ent, Eloc);
2173             else
2174                Error_Msg_NEL (Msgc (1 .. Msgl), N, Etype (N), Eloc);
2175             end if;
2176
2177             if Wmsg then
2178                if Inside_Init_Proc then
2179                   Error_Msg_NEL
2180                     ("\?& will be raised for objects of this type",
2181                      N, Standard_Constraint_Error, Eloc);
2182                else
2183                   Error_Msg_NEL
2184                     ("\?& will be raised at run time",
2185                      N, Standard_Constraint_Error, Eloc);
2186                end if;
2187
2188             else
2189                Error_Msg
2190                  ("\static expression fails Constraint_Check", Eloc);
2191                Set_Error_Posted (N);
2192             end if;
2193          end if;
2194       end if;
2195
2196       return N;
2197    end Compile_Time_Constraint_Error;
2198
2199    -----------------------
2200    -- Conditional_Delay --
2201    -----------------------
2202
2203    procedure Conditional_Delay (New_Ent, Old_Ent : Entity_Id) is
2204    begin
2205       if Has_Delayed_Freeze (Old_Ent) and then not Is_Frozen (Old_Ent) then
2206          Set_Has_Delayed_Freeze (New_Ent);
2207       end if;
2208    end Conditional_Delay;
2209
2210    -------------------------
2211    -- Copy_Parameter_List --
2212    -------------------------
2213
2214    function Copy_Parameter_List (Subp_Id : Entity_Id) return List_Id is
2215       Loc    : constant Source_Ptr := Sloc (Subp_Id);
2216       Plist  : List_Id;
2217       Formal : Entity_Id;
2218
2219    begin
2220       if No (First_Formal (Subp_Id)) then
2221          return No_List;
2222       else
2223          Plist := New_List;
2224          Formal := First_Formal (Subp_Id);
2225          while Present (Formal) loop
2226             Append
2227               (Make_Parameter_Specification (Loc,
2228                 Defining_Identifier =>
2229                   Make_Defining_Identifier (Sloc (Formal),
2230                     Chars => Chars (Formal)),
2231                 In_Present  => In_Present (Parent (Formal)),
2232                 Out_Present => Out_Present (Parent (Formal)),
2233              Parameter_Type =>
2234                   New_Reference_To (Etype (Formal), Loc),
2235                 Expression =>
2236                   New_Copy_Tree (Expression (Parent (Formal)))),
2237               Plist);
2238
2239             Next_Formal (Formal);
2240          end loop;
2241       end if;
2242
2243       return Plist;
2244    end Copy_Parameter_List;
2245
2246    --------------------
2247    -- Current_Entity --
2248    --------------------
2249
2250    --  The currently visible definition for a given identifier is the
2251    --  one most chained at the start of the visibility chain, i.e. the
2252    --  one that is referenced by the Node_Id value of the name of the
2253    --  given identifier.
2254
2255    function Current_Entity (N : Node_Id) return Entity_Id is
2256    begin
2257       return Get_Name_Entity_Id (Chars (N));
2258    end Current_Entity;
2259
2260    -----------------------------
2261    -- Current_Entity_In_Scope --
2262    -----------------------------
2263
2264    function Current_Entity_In_Scope (N : Node_Id) return Entity_Id is
2265       E  : Entity_Id;
2266       CS : constant Entity_Id := Current_Scope;
2267
2268       Transient_Case : constant Boolean := Scope_Is_Transient;
2269
2270    begin
2271       E := Get_Name_Entity_Id (Chars (N));
2272       while Present (E)
2273         and then Scope (E) /= CS
2274         and then (not Transient_Case or else Scope (E) /= Scope (CS))
2275       loop
2276          E := Homonym (E);
2277       end loop;
2278
2279       return E;
2280    end Current_Entity_In_Scope;
2281
2282    -------------------
2283    -- Current_Scope --
2284    -------------------
2285
2286    function Current_Scope return Entity_Id is
2287    begin
2288       if Scope_Stack.Last = -1 then
2289          return Standard_Standard;
2290       else
2291          declare
2292             C : constant Entity_Id :=
2293                   Scope_Stack.Table (Scope_Stack.Last).Entity;
2294          begin
2295             if Present (C) then
2296                return C;
2297             else
2298                return Standard_Standard;
2299             end if;
2300          end;
2301       end if;
2302    end Current_Scope;
2303
2304    ------------------------
2305    -- Current_Subprogram --
2306    ------------------------
2307
2308    function Current_Subprogram return Entity_Id is
2309       Scop : constant Entity_Id := Current_Scope;
2310    begin
2311       if Is_Subprogram (Scop) or else Is_Generic_Subprogram (Scop) then
2312          return Scop;
2313       else
2314          return Enclosing_Subprogram (Scop);
2315       end if;
2316    end Current_Subprogram;
2317
2318    ------------------------------
2319    -- Mark_Non_ALFA_Subprogram --
2320    ------------------------------
2321
2322    procedure Mark_Non_ALFA_Subprogram is
2323    begin
2324       --  Isolate marking of the current subprogram body so that the body of
2325       --  Mark_Non_ALFA_Subprogram is small and inlined.
2326
2327       if ALFA_Mode then
2328          Mark_Non_ALFA_Subprogram_Unconditional;
2329       end if;
2330    end Mark_Non_ALFA_Subprogram;
2331
2332    --------------------------------------------
2333    -- Mark_Non_ALFA_Subprogram_Unconditional --
2334    --------------------------------------------
2335
2336    procedure Mark_Non_ALFA_Subprogram_Unconditional is
2337       Cur_Subp : constant Entity_Id := Current_Subprogram;
2338
2339    begin
2340       if Present (Cur_Subp)
2341         and then (Is_Subprogram (Cur_Subp)
2342                    or else Is_Generic_Subprogram (Cur_Subp))
2343       then
2344          --  If the non-ALFA construct is in a precondition or postcondition,
2345          --  then mark the subprogram as not in ALFA. Otherwise, mark the
2346          --  subprogram body as not in ALFA.
2347
2348          --  This comment just says what is done, but not why ??? and it
2349          --  just repeats what is in the spec ???
2350
2351          if In_Pre_Post_Expression then
2352             Set_Is_In_ALFA (Cur_Subp, False);
2353          else
2354             Set_Body_Is_In_ALFA (Cur_Subp, False);
2355          end if;
2356       end if;
2357    end Mark_Non_ALFA_Subprogram_Unconditional;
2358
2359    ---------------------
2360    -- Defining_Entity --
2361    ---------------------
2362
2363    function Defining_Entity (N : Node_Id) return Entity_Id is
2364       K   : constant Node_Kind := Nkind (N);
2365       Err : Entity_Id := Empty;
2366
2367    begin
2368       case K is
2369          when
2370            N_Subprogram_Declaration                 |
2371            N_Abstract_Subprogram_Declaration        |
2372            N_Subprogram_Body                        |
2373            N_Package_Declaration                    |
2374            N_Subprogram_Renaming_Declaration        |
2375            N_Subprogram_Body_Stub                   |
2376            N_Generic_Subprogram_Declaration         |
2377            N_Generic_Package_Declaration            |
2378            N_Formal_Subprogram_Declaration
2379          =>
2380             return Defining_Entity (Specification (N));
2381
2382          when
2383            N_Component_Declaration                  |
2384            N_Defining_Program_Unit_Name             |
2385            N_Discriminant_Specification             |
2386            N_Entry_Body                             |
2387            N_Entry_Declaration                      |
2388            N_Entry_Index_Specification              |
2389            N_Exception_Declaration                  |
2390            N_Exception_Renaming_Declaration         |
2391            N_Formal_Object_Declaration              |
2392            N_Formal_Package_Declaration             |
2393            N_Formal_Type_Declaration                |
2394            N_Full_Type_Declaration                  |
2395            N_Implicit_Label_Declaration             |
2396            N_Incomplete_Type_Declaration            |
2397            N_Loop_Parameter_Specification           |
2398            N_Number_Declaration                     |
2399            N_Object_Declaration                     |
2400            N_Object_Renaming_Declaration            |
2401            N_Package_Body_Stub                      |
2402            N_Parameter_Specification                |
2403            N_Private_Extension_Declaration          |
2404            N_Private_Type_Declaration               |
2405            N_Protected_Body                         |
2406            N_Protected_Body_Stub                    |
2407            N_Protected_Type_Declaration             |
2408            N_Single_Protected_Declaration           |
2409            N_Single_Task_Declaration                |
2410            N_Subtype_Declaration                    |
2411            N_Task_Body                              |
2412            N_Task_Body_Stub                         |
2413            N_Task_Type_Declaration
2414          =>
2415             return Defining_Identifier (N);
2416
2417          when N_Subunit =>
2418             return Defining_Entity (Proper_Body (N));
2419
2420          when
2421            N_Function_Instantiation                 |
2422            N_Function_Specification                 |
2423            N_Generic_Function_Renaming_Declaration  |
2424            N_Generic_Package_Renaming_Declaration   |
2425            N_Generic_Procedure_Renaming_Declaration |
2426            N_Package_Body                           |
2427            N_Package_Instantiation                  |
2428            N_Package_Renaming_Declaration           |
2429            N_Package_Specification                  |
2430            N_Procedure_Instantiation                |
2431            N_Procedure_Specification
2432          =>
2433             declare
2434                Nam : constant Node_Id := Defining_Unit_Name (N);
2435
2436             begin
2437                if Nkind (Nam) in N_Entity then
2438                   return Nam;
2439
2440                --  For Error, make up a name and attach to declaration
2441                --  so we can continue semantic analysis
2442
2443                elsif Nam = Error then
2444                   Err := Make_Temporary (Sloc (N), 'T');
2445                   Set_Defining_Unit_Name (N, Err);
2446
2447                   return Err;
2448                --  If not an entity, get defining identifier
2449
2450                else
2451                   return Defining_Identifier (Nam);
2452                end if;
2453             end;
2454
2455          when N_Block_Statement =>
2456             return Entity (Identifier (N));
2457
2458          when others =>
2459             raise Program_Error;
2460
2461       end case;
2462    end Defining_Entity;
2463
2464    --------------------------
2465    -- Denotes_Discriminant --
2466    --------------------------
2467
2468    function Denotes_Discriminant
2469      (N                : Node_Id;
2470       Check_Concurrent : Boolean := False) return Boolean
2471    is
2472       E : Entity_Id;
2473    begin
2474       if not Is_Entity_Name (N)
2475         or else No (Entity (N))
2476       then
2477          return False;
2478       else
2479          E := Entity (N);
2480       end if;
2481
2482       --  If we are checking for a protected type, the discriminant may have
2483       --  been rewritten as the corresponding discriminal of the original type
2484       --  or of the corresponding concurrent record, depending on whether we
2485       --  are in the spec or body of the protected type.
2486
2487       return Ekind (E) = E_Discriminant
2488         or else
2489           (Check_Concurrent
2490             and then Ekind (E) = E_In_Parameter
2491             and then Present (Discriminal_Link (E))
2492             and then
2493               (Is_Concurrent_Type (Scope (Discriminal_Link (E)))
2494                 or else
2495                   Is_Concurrent_Record_Type (Scope (Discriminal_Link (E)))));
2496
2497    end Denotes_Discriminant;
2498
2499    -------------------------
2500    -- Denotes_Same_Object --
2501    -------------------------
2502
2503    function Denotes_Same_Object (A1, A2 : Node_Id) return Boolean is
2504       Obj1 : Node_Id := A1;
2505       Obj2 : Node_Id := A2;
2506
2507       procedure Check_Renaming (Obj : in out Node_Id);
2508       --  If an object is a renaming, examine renamed object. If it is a
2509       --  dereference of a variable, or an indexed expression with non-constant
2510       --  indexes, no overlap check can be reported.
2511
2512       --------------------
2513       -- Check_Renaming --
2514       --------------------
2515
2516       procedure Check_Renaming (Obj : in out Node_Id) is
2517       begin
2518          if Is_Entity_Name (Obj)
2519            and then Present (Renamed_Entity (Entity (Obj)))
2520          then
2521             Obj := Renamed_Entity (Entity (Obj));
2522             if Nkind (Obj) = N_Explicit_Dereference
2523               and then Is_Variable (Prefix (Obj))
2524             then
2525                Obj := Empty;
2526
2527             elsif Nkind (Obj) = N_Indexed_Component then
2528                declare
2529                   Indx : Node_Id;
2530
2531                begin
2532                   Indx := First (Expressions (Obj));
2533                   while Present (Indx) loop
2534                      if not Is_OK_Static_Expression (Indx) then
2535                         Obj := Empty;
2536                         exit;
2537                      end if;
2538
2539                      Next_Index (Indx);
2540                   end loop;
2541                end;
2542             end if;
2543          end if;
2544       end Check_Renaming;
2545
2546    --  Start of processing for Denotes_Same_Object
2547
2548    begin
2549       Check_Renaming (Obj1);
2550       Check_Renaming (Obj2);
2551
2552       if No (Obj1)
2553         or else No (Obj2)
2554       then
2555          return False;
2556       end if;
2557
2558       --  If we have entity names, then must be same entity
2559
2560       if Is_Entity_Name (Obj1) then
2561          if Is_Entity_Name (Obj2) then
2562             return Entity (Obj1) = Entity (Obj2);
2563          else
2564             return False;
2565          end if;
2566
2567       --  No match if not same node kind
2568
2569       elsif Nkind (Obj1) /= Nkind (Obj2) then
2570          return False;
2571
2572       --  For selected components, must have same prefix and selector
2573
2574       elsif Nkind (Obj1) = N_Selected_Component then
2575          return Denotes_Same_Object (Prefix (Obj1), Prefix (Obj2))
2576            and then
2577          Entity (Selector_Name (Obj1)) = Entity (Selector_Name (Obj2));
2578
2579       --  For explicit dereferences, prefixes must be same
2580
2581       elsif Nkind (Obj1) = N_Explicit_Dereference then
2582          return Denotes_Same_Object (Prefix (Obj1), Prefix (Obj2));
2583
2584       --  For indexed components, prefixes and all subscripts must be the same
2585
2586       elsif Nkind (Obj1) = N_Indexed_Component then
2587          if Denotes_Same_Object (Prefix (Obj1), Prefix (Obj2)) then
2588             declare
2589                Indx1 : Node_Id;
2590                Indx2 : Node_Id;
2591
2592             begin
2593                Indx1 := First (Expressions (Obj1));
2594                Indx2 := First (Expressions (Obj2));
2595                while Present (Indx1) loop
2596
2597                   --  Indexes must denote the same static value or same object
2598
2599                   if Is_OK_Static_Expression (Indx1) then
2600                      if not Is_OK_Static_Expression (Indx2) then
2601                         return False;
2602
2603                      elsif Expr_Value (Indx1) /= Expr_Value (Indx2) then
2604                         return False;
2605                      end if;
2606
2607                   elsif not Denotes_Same_Object (Indx1, Indx2) then
2608                      return False;
2609                   end if;
2610
2611                   Next (Indx1);
2612                   Next (Indx2);
2613                end loop;
2614
2615                return True;
2616             end;
2617          else
2618             return False;
2619          end if;
2620
2621       --  For slices, prefixes must match and bounds must match
2622
2623       elsif Nkind (Obj1) = N_Slice
2624         and then Denotes_Same_Object (Prefix (Obj1), Prefix (Obj2))
2625       then
2626          declare
2627             Lo1, Lo2, Hi1, Hi2 : Node_Id;
2628
2629          begin
2630             Get_Index_Bounds (Etype (Obj1), Lo1, Hi1);
2631             Get_Index_Bounds (Etype (Obj2), Lo2, Hi2);
2632
2633             --  Check whether bounds are statically identical. There is no
2634             --  attempt to detect partial overlap of slices.
2635
2636             return Denotes_Same_Object (Lo1, Lo2)
2637               and then Denotes_Same_Object (Hi1, Hi2);
2638          end;
2639
2640          --  Literals will appear as indexes. Isn't this where we should check
2641          --  Known_At_Compile_Time at least if we are generating warnings ???
2642
2643       elsif Nkind (Obj1) = N_Integer_Literal then
2644          return Intval (Obj1) = Intval (Obj2);
2645
2646       else
2647          return False;
2648       end if;
2649    end Denotes_Same_Object;
2650
2651    -------------------------
2652    -- Denotes_Same_Prefix --
2653    -------------------------
2654
2655    function Denotes_Same_Prefix (A1, A2 : Node_Id) return Boolean is
2656
2657    begin
2658       if Is_Entity_Name (A1) then
2659          if Nkind_In (A2, N_Selected_Component, N_Indexed_Component)
2660            and then not Is_Access_Type (Etype (A1))
2661          then
2662             return Denotes_Same_Object (A1, Prefix (A2))
2663               or else Denotes_Same_Prefix (A1, Prefix (A2));
2664          else
2665             return False;
2666          end if;
2667
2668       elsif Is_Entity_Name (A2) then
2669          return Denotes_Same_Prefix (A2, A1);
2670
2671       elsif Nkind_In (A1, N_Selected_Component, N_Indexed_Component, N_Slice)
2672               and then
2673             Nkind_In (A2, N_Selected_Component, N_Indexed_Component, N_Slice)
2674       then
2675          declare
2676             Root1, Root2 : Node_Id;
2677             Depth1, Depth2 : Int := 0;
2678
2679          begin
2680             Root1 := Prefix (A1);
2681             while not Is_Entity_Name (Root1) loop
2682                if not Nkind_In
2683                  (Root1, N_Selected_Component, N_Indexed_Component)
2684                then
2685                   return False;
2686                else
2687                   Root1 := Prefix (Root1);
2688                end if;
2689
2690                Depth1 := Depth1 + 1;
2691             end loop;
2692
2693             Root2 := Prefix (A2);
2694             while not Is_Entity_Name (Root2) loop
2695                if not Nkind_In
2696                  (Root2, N_Selected_Component, N_Indexed_Component)
2697                then
2698                   return False;
2699                else
2700                   Root2 := Prefix (Root2);
2701                end if;
2702
2703                Depth2 := Depth2 + 1;
2704             end loop;
2705
2706             --  If both have the same depth and they do not denote the same
2707             --  object, they are disjoint and not warning is needed.
2708
2709             if Depth1 = Depth2 then
2710                return False;
2711
2712             elsif Depth1 > Depth2 then
2713                Root1 := Prefix (A1);
2714                for I in 1 .. Depth1 - Depth2 - 1 loop
2715                   Root1 := Prefix (Root1);
2716                end loop;
2717
2718                return Denotes_Same_Object (Root1, A2);
2719
2720             else
2721                Root2 := Prefix (A2);
2722                for I in 1 .. Depth2 - Depth1 - 1 loop
2723                   Root2 := Prefix (Root2);
2724                end loop;
2725
2726                return Denotes_Same_Object (A1, Root2);
2727             end if;
2728          end;
2729
2730       else
2731          return False;
2732       end if;
2733    end Denotes_Same_Prefix;
2734
2735    ----------------------
2736    -- Denotes_Variable --
2737    ----------------------
2738
2739    function Denotes_Variable (N : Node_Id) return Boolean is
2740    begin
2741       return Is_Variable (N) and then Paren_Count (N) = 0;
2742    end Denotes_Variable;
2743
2744    -----------------------------
2745    -- Depends_On_Discriminant --
2746    -----------------------------
2747
2748    function Depends_On_Discriminant (N : Node_Id) return Boolean is
2749       L : Node_Id;
2750       H : Node_Id;
2751
2752    begin
2753       Get_Index_Bounds (N, L, H);
2754       return Denotes_Discriminant (L) or else Denotes_Discriminant (H);
2755    end Depends_On_Discriminant;
2756
2757    -------------------------
2758    -- Designate_Same_Unit --
2759    -------------------------
2760
2761    function Designate_Same_Unit
2762      (Name1 : Node_Id;
2763       Name2 : Node_Id) return Boolean
2764    is
2765       K1 : constant Node_Kind := Nkind (Name1);
2766       K2 : constant Node_Kind := Nkind (Name2);
2767
2768       function Prefix_Node (N : Node_Id) return Node_Id;
2769       --  Returns the parent unit name node of a defining program unit name
2770       --  or the prefix if N is a selected component or an expanded name.
2771
2772       function Select_Node (N : Node_Id) return Node_Id;
2773       --  Returns the defining identifier node of a defining program unit
2774       --  name or  the selector node if N is a selected component or an
2775       --  expanded name.
2776
2777       -----------------
2778       -- Prefix_Node --
2779       -----------------
2780
2781       function Prefix_Node (N : Node_Id) return Node_Id is
2782       begin
2783          if Nkind (N) = N_Defining_Program_Unit_Name then
2784             return Name (N);
2785
2786          else
2787             return Prefix (N);
2788          end if;
2789       end Prefix_Node;
2790
2791       -----------------
2792       -- Select_Node --
2793       -----------------
2794
2795       function Select_Node (N : Node_Id) return Node_Id is
2796       begin
2797          if Nkind (N) = N_Defining_Program_Unit_Name then
2798             return Defining_Identifier (N);
2799
2800          else
2801             return Selector_Name (N);
2802          end if;
2803       end Select_Node;
2804
2805    --  Start of processing for Designate_Next_Unit
2806
2807    begin
2808       if (K1 = N_Identifier or else
2809           K1 = N_Defining_Identifier)
2810         and then
2811          (K2 = N_Identifier or else
2812           K2 = N_Defining_Identifier)
2813       then
2814          return Chars (Name1) = Chars (Name2);
2815
2816       elsif
2817          (K1 = N_Expanded_Name      or else
2818           K1 = N_Selected_Component or else
2819           K1 = N_Defining_Program_Unit_Name)
2820         and then
2821          (K2 = N_Expanded_Name      or else
2822           K2 = N_Selected_Component or else
2823           K2 = N_Defining_Program_Unit_Name)
2824       then
2825          return
2826            (Chars (Select_Node (Name1)) = Chars (Select_Node (Name2)))
2827              and then
2828                Designate_Same_Unit (Prefix_Node (Name1), Prefix_Node (Name2));
2829
2830       else
2831          return False;
2832       end if;
2833    end Designate_Same_Unit;
2834
2835    --------------------------
2836    -- Enclosing_CPP_Parent --
2837    --------------------------
2838
2839    function Enclosing_CPP_Parent (Typ : Entity_Id) return Entity_Id is
2840       Parent_Typ : Entity_Id := Typ;
2841
2842    begin
2843       while not Is_CPP_Class (Parent_Typ)
2844          and then Etype (Parent_Typ) /= Parent_Typ
2845       loop
2846          Parent_Typ := Etype (Parent_Typ);
2847
2848          if Is_Private_Type (Parent_Typ) then
2849             Parent_Typ := Full_View (Base_Type (Parent_Typ));
2850          end if;
2851       end loop;
2852
2853       pragma Assert (Is_CPP_Class (Parent_Typ));
2854       return Parent_Typ;
2855    end Enclosing_CPP_Parent;
2856
2857    ----------------------------
2858    -- Enclosing_Generic_Body --
2859    ----------------------------
2860
2861    function Enclosing_Generic_Body
2862      (N : Node_Id) return Node_Id
2863    is
2864       P    : Node_Id;
2865       Decl : Node_Id;
2866       Spec : Node_Id;
2867
2868    begin
2869       P := Parent (N);
2870       while Present (P) loop
2871          if Nkind (P) = N_Package_Body
2872            or else Nkind (P) = N_Subprogram_Body
2873          then
2874             Spec := Corresponding_Spec (P);
2875
2876             if Present (Spec) then
2877                Decl := Unit_Declaration_Node (Spec);
2878
2879                if Nkind (Decl) = N_Generic_Package_Declaration
2880                  or else Nkind (Decl) = N_Generic_Subprogram_Declaration
2881                then
2882                   return P;
2883                end if;
2884             end if;
2885          end if;
2886
2887          P := Parent (P);
2888       end loop;
2889
2890       return Empty;
2891    end Enclosing_Generic_Body;
2892
2893    ----------------------------
2894    -- Enclosing_Generic_Unit --
2895    ----------------------------
2896
2897    function Enclosing_Generic_Unit
2898      (N : Node_Id) return Node_Id
2899    is
2900       P    : Node_Id;
2901       Decl : Node_Id;
2902       Spec : Node_Id;
2903
2904    begin
2905       P := Parent (N);
2906       while Present (P) loop
2907          if Nkind (P) = N_Generic_Package_Declaration
2908            or else Nkind (P) = N_Generic_Subprogram_Declaration
2909          then
2910             return P;
2911
2912          elsif Nkind (P) = N_Package_Body
2913            or else Nkind (P) = N_Subprogram_Body
2914          then
2915             Spec := Corresponding_Spec (P);
2916
2917             if Present (Spec) then
2918                Decl := Unit_Declaration_Node (Spec);
2919
2920                if Nkind (Decl) = N_Generic_Package_Declaration
2921                  or else Nkind (Decl) = N_Generic_Subprogram_Declaration
2922                then
2923                   return Decl;
2924                end if;
2925             end if;
2926          end if;
2927
2928          P := Parent (P);
2929       end loop;
2930
2931       return Empty;
2932    end Enclosing_Generic_Unit;
2933
2934    -------------------------------
2935    -- Enclosing_Lib_Unit_Entity --
2936    -------------------------------
2937
2938    function Enclosing_Lib_Unit_Entity return Entity_Id is
2939       Unit_Entity : Entity_Id;
2940
2941    begin
2942       --  Look for enclosing library unit entity by following scope links.
2943       --  Equivalent to, but faster than indexing through the scope stack.
2944
2945       Unit_Entity := Current_Scope;
2946       while (Present (Scope (Unit_Entity))
2947         and then Scope (Unit_Entity) /= Standard_Standard)
2948         and not Is_Child_Unit (Unit_Entity)
2949       loop
2950          Unit_Entity := Scope (Unit_Entity);
2951       end loop;
2952
2953       return Unit_Entity;
2954    end Enclosing_Lib_Unit_Entity;
2955
2956    -----------------------------
2957    -- Enclosing_Lib_Unit_Node --
2958    -----------------------------
2959
2960    function Enclosing_Lib_Unit_Node (N : Node_Id) return Node_Id is
2961       Current_Node : Node_Id;
2962
2963    begin
2964       Current_Node := N;
2965       while Present (Current_Node)
2966         and then Nkind (Current_Node) /= N_Compilation_Unit
2967       loop
2968          Current_Node := Parent (Current_Node);
2969       end loop;
2970
2971       if Nkind (Current_Node) /= N_Compilation_Unit then
2972          return Empty;
2973       end if;
2974
2975       return Current_Node;
2976    end Enclosing_Lib_Unit_Node;
2977
2978    -----------------------
2979    -- Enclosing_Package --
2980    -----------------------
2981
2982    function Enclosing_Package (E : Entity_Id) return Entity_Id is
2983       Dynamic_Scope : constant Entity_Id := Enclosing_Dynamic_Scope (E);
2984
2985    begin
2986       if Dynamic_Scope = Standard_Standard then
2987          return Standard_Standard;
2988
2989       elsif Dynamic_Scope = Empty then
2990          return Empty;
2991
2992       elsif Ekind_In (Dynamic_Scope, E_Package, E_Package_Body,
2993                       E_Generic_Package)
2994       then
2995          return Dynamic_Scope;
2996
2997       else
2998          return Enclosing_Package (Dynamic_Scope);
2999       end if;
3000    end Enclosing_Package;
3001
3002    --------------------------
3003    -- Enclosing_Subprogram --
3004    --------------------------
3005
3006    function Enclosing_Subprogram (E : Entity_Id) return Entity_Id is
3007       Dynamic_Scope : constant Entity_Id := Enclosing_Dynamic_Scope (E);
3008
3009    begin
3010       if Dynamic_Scope = Standard_Standard then
3011          return Empty;
3012
3013       elsif Dynamic_Scope = Empty then
3014          return Empty;
3015
3016       elsif Ekind (Dynamic_Scope) = E_Subprogram_Body then
3017          return Corresponding_Spec (Parent (Parent (Dynamic_Scope)));
3018
3019       elsif Ekind (Dynamic_Scope) = E_Block
3020         or else Ekind (Dynamic_Scope) = E_Return_Statement
3021       then
3022          return Enclosing_Subprogram (Dynamic_Scope);
3023
3024       elsif Ekind (Dynamic_Scope) = E_Task_Type then
3025          return Get_Task_Body_Procedure (Dynamic_Scope);
3026
3027       elsif Ekind (Dynamic_Scope) = E_Limited_Private_Type
3028         and then Present (Full_View (Dynamic_Scope))
3029         and then Ekind (Full_View (Dynamic_Scope)) = E_Task_Type
3030       then
3031          return Get_Task_Body_Procedure (Full_View (Dynamic_Scope));
3032
3033       --  No body is generated if the protected operation is eliminated
3034
3035       elsif Convention (Dynamic_Scope) = Convention_Protected
3036         and then not Is_Eliminated (Dynamic_Scope)
3037         and then Present (Protected_Body_Subprogram (Dynamic_Scope))
3038       then
3039          return Protected_Body_Subprogram (Dynamic_Scope);
3040
3041       else
3042          return Dynamic_Scope;
3043       end if;
3044    end Enclosing_Subprogram;
3045
3046    ------------------------
3047    -- Ensure_Freeze_Node --
3048    ------------------------
3049
3050    procedure Ensure_Freeze_Node (E : Entity_Id) is
3051       FN : Node_Id;
3052
3053    begin
3054       if No (Freeze_Node (E)) then
3055          FN := Make_Freeze_Entity (Sloc (E));
3056          Set_Has_Delayed_Freeze (E);
3057          Set_Freeze_Node (E, FN);
3058          Set_Access_Types_To_Process (FN, No_Elist);
3059          Set_TSS_Elist (FN, No_Elist);
3060          Set_Entity (FN, E);
3061       end if;
3062    end Ensure_Freeze_Node;
3063
3064    ----------------
3065    -- Enter_Name --
3066    ----------------
3067
3068    procedure Enter_Name (Def_Id : Entity_Id) is
3069       C : constant Entity_Id := Current_Entity (Def_Id);
3070       E : constant Entity_Id := Current_Entity_In_Scope (Def_Id);
3071       S : constant Entity_Id := Current_Scope;
3072
3073    begin
3074       Generate_Definition (Def_Id);
3075
3076       --  Add new name to current scope declarations. Check for duplicate
3077       --  declaration, which may or may not be a genuine error.
3078
3079       if Present (E) then
3080
3081          --  Case of previous entity entered because of a missing declaration
3082          --  or else a bad subtype indication. Best is to use the new entity,
3083          --  and make the previous one invisible.
3084
3085          if Etype (E) = Any_Type then
3086             Set_Is_Immediately_Visible (E, False);
3087
3088          --  Case of renaming declaration constructed for package instances.
3089          --  if there is an explicit declaration with the same identifier,
3090          --  the renaming is not immediately visible any longer, but remains
3091          --  visible through selected component notation.
3092
3093          elsif Nkind (Parent (E)) = N_Package_Renaming_Declaration
3094            and then not Comes_From_Source (E)
3095          then
3096             Set_Is_Immediately_Visible (E, False);
3097
3098          --  The new entity may be the package renaming, which has the same
3099          --  same name as a generic formal which has been seen already.
3100
3101          elsif Nkind (Parent (Def_Id)) = N_Package_Renaming_Declaration
3102             and then not Comes_From_Source (Def_Id)
3103          then
3104             Set_Is_Immediately_Visible (E, False);
3105
3106          --  For a fat pointer corresponding to a remote access to subprogram,
3107          --  we use the same identifier as the RAS type, so that the proper
3108          --  name appears in the stub. This type is only retrieved through
3109          --  the RAS type and never by visibility, and is not added to the
3110          --  visibility list (see below).
3111
3112          elsif Nkind (Parent (Def_Id)) = N_Full_Type_Declaration
3113            and then Present (Corresponding_Remote_Type (Def_Id))
3114          then
3115             null;
3116
3117          --  A controller component for a type extension overrides the
3118          --  inherited component.
3119
3120          elsif Chars (E) = Name_uController then
3121             null;
3122
3123          --  Case of an implicit operation or derived literal. The new entity
3124          --  hides the implicit one,  which is removed from all visibility,
3125          --  i.e. the entity list of its scope, and homonym chain of its name.
3126
3127          elsif (Is_Overloadable (E) and then Is_Inherited_Operation (E))
3128            or else Is_Internal (E)
3129          then
3130             declare
3131                Prev     : Entity_Id;
3132                Prev_Vis : Entity_Id;
3133                Decl     : constant Node_Id := Parent (E);
3134
3135             begin
3136                --  If E is an implicit declaration, it cannot be the first
3137                --  entity in the scope.
3138
3139                Prev := First_Entity (Current_Scope);
3140                while Present (Prev)
3141                  and then Next_Entity (Prev) /= E
3142                loop
3143                   Next_Entity (Prev);
3144                end loop;
3145
3146                if No (Prev) then
3147
3148                   --  If E is not on the entity chain of the current scope,
3149                   --  it is an implicit declaration in the generic formal
3150                   --  part of a generic subprogram. When analyzing the body,
3151                   --  the generic formals are visible but not on the entity
3152                   --  chain of the subprogram. The new entity will become
3153                   --  the visible one in the body.
3154
3155                   pragma Assert
3156                     (Nkind (Parent (Decl)) = N_Generic_Subprogram_Declaration);
3157                   null;
3158
3159                else
3160                   Set_Next_Entity (Prev, Next_Entity (E));
3161
3162                   if No (Next_Entity (Prev)) then
3163                      Set_Last_Entity (Current_Scope, Prev);
3164                   end if;
3165
3166                   if E = Current_Entity (E) then
3167                      Prev_Vis := Empty;
3168
3169                   else
3170                      Prev_Vis := Current_Entity (E);
3171                      while Homonym (Prev_Vis) /= E loop
3172                         Prev_Vis := Homonym (Prev_Vis);
3173                      end loop;
3174                   end if;
3175
3176                   if Present (Prev_Vis)  then
3177
3178                      --  Skip E in the visibility chain
3179
3180                      Set_Homonym (Prev_Vis, Homonym (E));
3181
3182                   else
3183                      Set_Name_Entity_Id (Chars (E), Homonym (E));
3184                   end if;
3185                end if;
3186             end;
3187
3188          --  This section of code could use a comment ???
3189
3190          elsif Present (Etype (E))
3191            and then Is_Concurrent_Type (Etype (E))
3192            and then E = Def_Id
3193          then
3194             return;
3195
3196          --  If the homograph is a protected component renaming, it should not
3197          --  be hiding the current entity. Such renamings are treated as weak
3198          --  declarations.
3199
3200          elsif Is_Prival (E) then
3201             Set_Is_Immediately_Visible (E, False);
3202
3203          --  In this case the current entity is a protected component renaming.
3204          --  Perform minimal decoration by setting the scope and return since
3205          --  the prival should not be hiding other visible entities.
3206
3207          elsif Is_Prival (Def_Id) then
3208             Set_Scope (Def_Id, Current_Scope);
3209             return;
3210
3211          --  Analogous to privals, the discriminal generated for an entry index
3212          --  parameter acts as a weak declaration. Perform minimal decoration
3213          --  to avoid bogus errors.
3214
3215          elsif Is_Discriminal (Def_Id)
3216            and then Ekind (Discriminal_Link (Def_Id)) = E_Entry_Index_Parameter
3217          then
3218             Set_Scope (Def_Id, Current_Scope);
3219             return;
3220
3221          --  In the body or private part of an instance, a type extension may
3222          --  introduce a component with the same name as that of an actual. The
3223          --  legality rule is not enforced, but the semantics of the full type
3224          --  with two components of same name are not clear at this point???
3225
3226          elsif In_Instance_Not_Visible then
3227             null;
3228
3229          --  When compiling a package body, some child units may have become
3230          --  visible. They cannot conflict with local entities that hide them.
3231
3232          elsif Is_Child_Unit (E)
3233            and then In_Open_Scopes (Scope (E))
3234            and then not Is_Immediately_Visible (E)
3235          then
3236             null;
3237
3238          --  Conversely, with front-end inlining we may compile the parent body
3239          --  first, and a child unit subsequently. The context is now the
3240          --  parent spec, and body entities are not visible.
3241
3242          elsif Is_Child_Unit (Def_Id)
3243            and then Is_Package_Body_Entity (E)
3244            and then not In_Package_Body (Current_Scope)
3245          then
3246             null;
3247
3248          --  Case of genuine duplicate declaration
3249
3250          else
3251             Error_Msg_Sloc := Sloc (E);
3252
3253             --  If the previous declaration is an incomplete type declaration
3254             --  this may be an attempt to complete it with a private type. The
3255             --  following avoids confusing cascaded errors.
3256
3257             if Nkind (Parent (E)) = N_Incomplete_Type_Declaration
3258               and then Nkind (Parent (Def_Id)) = N_Private_Type_Declaration
3259             then
3260                Error_Msg_N
3261                  ("incomplete type cannot be completed with a private " &
3262                   "declaration", Parent (Def_Id));
3263                Set_Is_Immediately_Visible (E, False);
3264                Set_Full_View (E, Def_Id);
3265
3266             --  An inherited component of a record conflicts with a new
3267             --  discriminant. The discriminant is inserted first in the scope,
3268             --  but the error should be posted on it, not on the component.
3269
3270             elsif Ekind (E) = E_Discriminant
3271               and then Present (Scope (Def_Id))
3272               and then Scope (Def_Id) /= Current_Scope
3273             then
3274                Error_Msg_Sloc := Sloc (Def_Id);
3275                Error_Msg_N ("& conflicts with declaration#", E);
3276                return;
3277
3278             --  If the name of the unit appears in its own context clause, a
3279             --  dummy package with the name has already been created, and the
3280             --  error emitted. Try to continue quietly.
3281
3282             elsif Error_Posted (E)
3283               and then Sloc (E) = No_Location
3284               and then Nkind (Parent (E)) = N_Package_Specification
3285               and then Current_Scope = Standard_Standard
3286             then
3287                Set_Scope (Def_Id, Current_Scope);
3288                return;
3289
3290             else
3291                Error_Msg_N ("& conflicts with declaration#", Def_Id);
3292
3293                --  Avoid cascaded messages with duplicate components in
3294                --  derived types.
3295
3296                if Ekind_In (E, E_Component, E_Discriminant) then
3297                   return;
3298                end if;
3299             end if;
3300
3301             if Nkind (Parent (Parent (Def_Id))) =
3302                 N_Generic_Subprogram_Declaration
3303               and then Def_Id =
3304                 Defining_Entity (Specification (Parent (Parent (Def_Id))))
3305             then
3306                Error_Msg_N ("\generic units cannot be overloaded", Def_Id);
3307             end if;
3308
3309             --  If entity is in standard, then we are in trouble, because it
3310             --  means that we have a library package with a duplicated name.
3311             --  That's hard to recover from, so abort!
3312
3313             if S = Standard_Standard then
3314                raise Unrecoverable_Error;
3315
3316             --  Otherwise we continue with the declaration. Having two
3317             --  identical declarations should not cause us too much trouble!
3318
3319             else
3320                null;
3321             end if;
3322          end if;
3323       end if;
3324
3325       --  If we fall through, declaration is OK, at least OK enough to continue
3326
3327       --  If Def_Id is a discriminant or a record component we are in the midst
3328       --  of inheriting components in a derived record definition. Preserve
3329       --  their Ekind and Etype.
3330
3331       if Ekind_In (Def_Id, E_Discriminant, E_Component) then
3332          null;
3333
3334       --  If a type is already set, leave it alone (happens when a type
3335       --  declaration is reanalyzed following a call to the optimizer).
3336
3337       elsif Present (Etype (Def_Id)) then
3338          null;
3339
3340       --  Otherwise, the kind E_Void insures that premature uses of the entity
3341       --  will be detected. Any_Type insures that no cascaded errors will occur
3342
3343       else
3344          Set_Ekind (Def_Id, E_Void);
3345          Set_Etype (Def_Id, Any_Type);
3346       end if;
3347
3348       --  Inherited discriminants and components in derived record types are
3349       --  immediately visible. Itypes are not.
3350
3351       if Ekind_In (Def_Id, E_Discriminant, E_Component)
3352         or else (No (Corresponding_Remote_Type (Def_Id))
3353                  and then not Is_Itype (Def_Id))
3354       then
3355          Set_Is_Immediately_Visible (Def_Id);
3356          Set_Current_Entity         (Def_Id);
3357       end if;
3358
3359       Set_Homonym       (Def_Id, C);
3360       Append_Entity     (Def_Id, S);
3361       Set_Public_Status (Def_Id);
3362
3363       --  Declaring a homonym is not allowed in SPARK ...
3364
3365       if Present (C)
3366         and then Restriction_Check_Required (SPARK)
3367       then
3368
3369          declare
3370             Enclosing_Subp : constant Node_Id := Enclosing_Subprogram (Def_Id);
3371             Enclosing_Pack : constant Node_Id := Enclosing_Package (Def_Id);
3372             Other_Scope    : constant Node_Id := Enclosing_Dynamic_Scope (C);
3373          begin
3374
3375             --  ... unless the new declaration is in a subprogram, and the
3376             --  visible declaration is a variable declaration or a parameter
3377             --  specification outside that subprogram.
3378
3379             if Present (Enclosing_Subp)
3380               and then Nkind_In (Parent (C), N_Object_Declaration,
3381                                  N_Parameter_Specification)
3382               and then not Scope_Within_Or_Same (Other_Scope, Enclosing_Subp)
3383             then
3384                null;
3385
3386             --  ... or the new declaration is in a package, and the visible
3387             --  declaration occurs outside that package.
3388
3389             elsif Present (Enclosing_Pack)
3390               and then not Scope_Within_Or_Same (Other_Scope, Enclosing_Pack)
3391             then
3392                null;
3393
3394             --  ... or the new declaration is a component declaration in a
3395             --  record type definition.
3396
3397             elsif Nkind (Parent (Def_Id)) = N_Component_Declaration then
3398                null;
3399
3400             --  Don't issue error for non-source entities
3401
3402             elsif Comes_From_Source (Def_Id)
3403               and then Comes_From_Source (C)
3404             then
3405                Error_Msg_Sloc := Sloc (C);
3406                Check_SPARK_Restriction
3407                  ("redeclaration of identifier &#", Def_Id);
3408             end if;
3409          end;
3410       end if;
3411
3412       --  Warn if new entity hides an old one
3413
3414       if Warn_On_Hiding and then Present (C)
3415
3416          --  Don't warn for record components since they always have a well
3417          --  defined scope which does not confuse other uses. Note that in
3418          --  some cases, Ekind has not been set yet.
3419
3420          and then Ekind (C) /= E_Component
3421          and then Ekind (C) /= E_Discriminant
3422          and then Nkind (Parent (C)) /= N_Component_Declaration
3423          and then Ekind (Def_Id) /= E_Component
3424          and then Ekind (Def_Id) /= E_Discriminant
3425          and then Nkind (Parent (Def_Id)) /= N_Component_Declaration
3426
3427          --  Don't warn for one character variables. It is too common to use
3428          --  such variables as locals and will just cause too many false hits.
3429
3430          and then Length_Of_Name (Chars (C)) /= 1
3431
3432          --  Don't warn for non-source entities
3433
3434          and then Comes_From_Source (C)
3435          and then Comes_From_Source (Def_Id)
3436
3437          --  Don't warn unless entity in question is in extended main source
3438
3439          and then In_Extended_Main_Source_Unit (Def_Id)
3440
3441          --  Finally, the hidden entity must be either immediately visible or
3442          --  use visible (i.e. from a used package).
3443
3444          and then
3445            (Is_Immediately_Visible (C)
3446               or else
3447             Is_Potentially_Use_Visible (C))
3448       then
3449          Error_Msg_Sloc := Sloc (C);
3450          Error_Msg_N ("declaration hides &#?", Def_Id);
3451       end if;
3452    end Enter_Name;
3453
3454    --------------------------
3455    -- Explain_Limited_Type --
3456    --------------------------
3457
3458    procedure Explain_Limited_Type (T : Entity_Id; N : Node_Id) is
3459       C : Entity_Id;
3460
3461    begin
3462       --  For array, component type must be limited
3463
3464       if Is_Array_Type (T) then
3465          Error_Msg_Node_2 := T;
3466          Error_Msg_NE
3467            ("\component type& of type& is limited", N, Component_Type (T));
3468          Explain_Limited_Type (Component_Type (T), N);
3469
3470       elsif Is_Record_Type (T) then
3471
3472          --  No need for extra messages if explicit limited record
3473
3474          if Is_Limited_Record (Base_Type (T)) then
3475             return;
3476          end if;
3477
3478          --  Otherwise find a limited component. Check only components that
3479          --  come from source, or inherited components that appear in the
3480          --  source of the ancestor.
3481
3482          C := First_Component (T);
3483          while Present (C) loop
3484             if Is_Limited_Type (Etype (C))
3485               and then
3486                 (Comes_From_Source (C)
3487                    or else
3488                      (Present (Original_Record_Component (C))
3489                        and then
3490                          Comes_From_Source (Original_Record_Component (C))))
3491             then
3492                Error_Msg_Node_2 := T;
3493                Error_Msg_NE ("\component& of type& has limited type", N, C);
3494                Explain_Limited_Type (Etype (C), N);
3495                return;
3496             end if;
3497
3498             Next_Component (C);
3499          end loop;
3500
3501          --  The type may be declared explicitly limited, even if no component
3502          --  of it is limited, in which case we fall out of the loop.
3503          return;
3504       end if;
3505    end Explain_Limited_Type;
3506
3507    -----------------
3508    -- Find_Actual --
3509    -----------------
3510
3511    procedure Find_Actual
3512      (N        : Node_Id;
3513       Formal   : out Entity_Id;
3514       Call     : out Node_Id)
3515    is
3516       Parnt  : constant Node_Id := Parent (N);
3517       Actual : Node_Id;
3518
3519    begin
3520       if (Nkind (Parnt) = N_Indexed_Component
3521             or else
3522           Nkind (Parnt) = N_Selected_Component)
3523         and then N = Prefix (Parnt)
3524       then
3525          Find_Actual (Parnt, Formal, Call);
3526          return;
3527
3528       elsif Nkind (Parnt) = N_Parameter_Association
3529         and then N = Explicit_Actual_Parameter (Parnt)
3530       then
3531          Call := Parent (Parnt);
3532
3533       elsif Nkind_In (Parnt, N_Procedure_Call_Statement, N_Function_Call) then
3534          Call := Parnt;
3535
3536       else
3537          Formal := Empty;
3538          Call   := Empty;
3539          return;
3540       end if;
3541
3542       --  If we have a call to a subprogram look for the parameter. Note that
3543       --  we exclude overloaded calls, since we don't know enough to be sure
3544       --  of giving the right answer in this case.
3545
3546       if Is_Entity_Name (Name (Call))
3547         and then Present (Entity (Name (Call)))
3548         and then Is_Overloadable (Entity (Name (Call)))
3549         and then not Is_Overloaded (Name (Call))
3550       then
3551          --  Fall here if we are definitely a parameter
3552
3553          Actual := First_Actual (Call);
3554          Formal := First_Formal (Entity (Name (Call)));
3555          while Present (Formal) and then Present (Actual) loop
3556             if Actual = N then
3557                return;
3558             else
3559                Actual := Next_Actual (Actual);
3560                Formal := Next_Formal (Formal);
3561             end if;
3562          end loop;
3563       end if;
3564
3565       --  Fall through here if we did not find matching actual
3566
3567       Formal := Empty;
3568       Call   := Empty;
3569    end Find_Actual;
3570
3571    ---------------------------
3572    -- Find_Body_Discriminal --
3573    ---------------------------
3574
3575    function Find_Body_Discriminal
3576      (Spec_Discriminant : Entity_Id) return Entity_Id
3577    is
3578       pragma Assert (Is_Concurrent_Record_Type (Scope (Spec_Discriminant)));
3579
3580       Tsk  : constant Entity_Id :=
3581                Corresponding_Concurrent_Type (Scope (Spec_Discriminant));
3582       Disc : Entity_Id;
3583
3584    begin
3585       --  Find discriminant of original concurrent type, and use its current
3586       --  discriminal, which is the renaming within the task/protected body.
3587
3588       Disc := First_Discriminant (Tsk);
3589       while Present (Disc) loop
3590          if Chars (Disc) = Chars (Spec_Discriminant) then
3591             return Discriminal (Disc);
3592          end if;
3593
3594          Next_Discriminant (Disc);
3595       end loop;
3596
3597       --  That loop should always succeed in finding a matching entry and
3598       --  returning. Fatal error if not.
3599
3600       raise Program_Error;
3601    end Find_Body_Discriminal;
3602
3603    -------------------------------------
3604    -- Find_Corresponding_Discriminant --
3605    -------------------------------------
3606
3607    function Find_Corresponding_Discriminant
3608      (Id  : Node_Id;
3609       Typ : Entity_Id) return Entity_Id
3610    is
3611       Par_Disc : Entity_Id;
3612       Old_Disc : Entity_Id;
3613       New_Disc : Entity_Id;
3614
3615    begin
3616       Par_Disc := Original_Record_Component (Original_Discriminant (Id));
3617
3618       --  The original type may currently be private, and the discriminant
3619       --  only appear on its full view.
3620
3621       if Is_Private_Type (Scope (Par_Disc))
3622         and then not Has_Discriminants (Scope (Par_Disc))
3623         and then Present (Full_View (Scope (Par_Disc)))
3624       then
3625          Old_Disc := First_Discriminant (Full_View (Scope (Par_Disc)));
3626       else
3627          Old_Disc := First_Discriminant (Scope (Par_Disc));
3628       end if;
3629
3630       if Is_Class_Wide_Type (Typ) then
3631          New_Disc := First_Discriminant (Root_Type (Typ));
3632       else
3633          New_Disc := First_Discriminant (Typ);
3634       end if;
3635
3636       while Present (Old_Disc) and then Present (New_Disc) loop
3637          if Old_Disc = Par_Disc  then
3638             return New_Disc;
3639          else
3640             Next_Discriminant (Old_Disc);
3641             Next_Discriminant (New_Disc);
3642          end if;
3643       end loop;
3644
3645       --  Should always find it
3646
3647       raise Program_Error;
3648    end Find_Corresponding_Discriminant;
3649
3650    --------------------------
3651    -- Find_Overlaid_Entity --
3652    --------------------------
3653
3654    procedure Find_Overlaid_Entity
3655      (N   : Node_Id;
3656       Ent : out Entity_Id;
3657       Off : out Boolean)
3658    is
3659       Expr : Node_Id;
3660
3661    begin
3662       --  We are looking for one of the two following forms:
3663
3664       --    for X'Address use Y'Address
3665
3666       --  or
3667
3668       --    Const : constant Address := expr;
3669       --    ...
3670       --    for X'Address use Const;
3671
3672       --  In the second case, the expr is either Y'Address, or recursively a
3673       --  constant that eventually references Y'Address.
3674
3675       Ent := Empty;
3676       Off := False;
3677
3678       if Nkind (N) = N_Attribute_Definition_Clause
3679         and then Chars (N) = Name_Address
3680       then
3681          Expr := Expression (N);
3682
3683          --  This loop checks the form of the expression for Y'Address,
3684          --  using recursion to deal with intermediate constants.
3685
3686          loop
3687             --  Check for Y'Address
3688
3689             if Nkind (Expr) = N_Attribute_Reference
3690               and then Attribute_Name (Expr) = Name_Address
3691             then
3692                Expr := Prefix (Expr);
3693                exit;
3694
3695                --  Check for Const where Const is a constant entity
3696
3697             elsif Is_Entity_Name (Expr)
3698               and then Ekind (Entity (Expr)) = E_Constant
3699             then
3700                Expr := Constant_Value (Entity (Expr));
3701
3702             --  Anything else does not need checking
3703
3704             else
3705                return;
3706             end if;
3707          end loop;
3708
3709          --  This loop checks the form of the prefix for an entity,
3710          --  using recursion to deal with intermediate components.
3711
3712          loop
3713             --  Check for Y where Y is an entity
3714
3715             if Is_Entity_Name (Expr) then
3716                Ent := Entity (Expr);
3717                return;
3718
3719             --  Check for components
3720
3721             elsif
3722                Nkind_In (Expr, N_Selected_Component, N_Indexed_Component) then
3723
3724                Expr := Prefix (Expr);
3725                Off := True;
3726
3727             --  Anything else does not need checking
3728
3729             else
3730                return;
3731             end if;
3732          end loop;
3733       end if;
3734    end Find_Overlaid_Entity;
3735
3736    -------------------------
3737    -- Find_Parameter_Type --
3738    -------------------------
3739
3740    function Find_Parameter_Type (Param : Node_Id) return Entity_Id is
3741    begin
3742       if Nkind (Param) /= N_Parameter_Specification then
3743          return Empty;
3744
3745       --  For an access parameter, obtain the type from the formal entity
3746       --  itself, because access to subprogram nodes do not carry a type.
3747       --  Shouldn't we always use the formal entity ???
3748
3749       elsif Nkind (Parameter_Type (Param)) = N_Access_Definition then
3750          return Etype (Defining_Identifier (Param));
3751
3752       else
3753          return Etype (Parameter_Type (Param));
3754       end if;
3755    end Find_Parameter_Type;
3756
3757    -----------------------------
3758    -- Find_Static_Alternative --
3759    -----------------------------
3760
3761    function Find_Static_Alternative (N : Node_Id) return Node_Id is
3762       Expr   : constant Node_Id := Expression (N);
3763       Val    : constant Uint    := Expr_Value (Expr);
3764       Alt    : Node_Id;
3765       Choice : Node_Id;
3766
3767    begin
3768       Alt := First (Alternatives (N));
3769
3770       Search : loop
3771          if Nkind (Alt) /= N_Pragma then
3772             Choice := First (Discrete_Choices (Alt));
3773             while Present (Choice) loop
3774
3775                --  Others choice, always matches
3776
3777                if Nkind (Choice) = N_Others_Choice then
3778                   exit Search;
3779
3780                --  Range, check if value is in the range
3781
3782                elsif Nkind (Choice) = N_Range then
3783                   exit Search when
3784                     Val >= Expr_Value (Low_Bound (Choice))
3785                       and then
3786                     Val <= Expr_Value (High_Bound (Choice));
3787
3788                --  Choice is a subtype name. Note that we know it must
3789                --  be a static subtype, since otherwise it would have
3790                --  been diagnosed as illegal.
3791
3792                elsif Is_Entity_Name (Choice)
3793                  and then Is_Type (Entity (Choice))
3794                then
3795                   exit Search when Is_In_Range (Expr, Etype (Choice),
3796                                                 Assume_Valid => False);
3797
3798                --  Choice is a subtype indication
3799
3800                elsif Nkind (Choice) = N_Subtype_Indication then
3801                   declare
3802                      C : constant Node_Id := Constraint (Choice);
3803                      R : constant Node_Id := Range_Expression (C);
3804
3805                   begin
3806                      exit Search when
3807                        Val >= Expr_Value (Low_Bound (R))
3808                          and then
3809                        Val <= Expr_Value (High_Bound (R));
3810                   end;
3811
3812                --  Choice is a simple expression
3813
3814                else
3815                   exit Search when Val = Expr_Value (Choice);
3816                end if;
3817
3818                Next (Choice);
3819             end loop;
3820          end if;
3821
3822          Next (Alt);
3823          pragma Assert (Present (Alt));
3824       end loop Search;
3825
3826       --  The above loop *must* terminate by finding a match, since
3827       --  we know the case statement is valid, and the value of the
3828       --  expression is known at compile time. When we fall out of
3829       --  the loop, Alt points to the alternative that we know will
3830       --  be selected at run time.
3831
3832       return Alt;
3833    end Find_Static_Alternative;
3834
3835    ------------------
3836    -- First_Actual --
3837    ------------------
3838
3839    function First_Actual (Node : Node_Id) return Node_Id is
3840       N : Node_Id;
3841
3842    begin
3843       if No (Parameter_Associations (Node)) then
3844          return Empty;
3845       end if;
3846
3847       N := First (Parameter_Associations (Node));
3848
3849       if Nkind (N) = N_Parameter_Association then
3850          return First_Named_Actual (Node);
3851       else
3852          return N;
3853       end if;
3854    end First_Actual;
3855
3856    -----------------------
3857    -- Gather_Components --
3858    -----------------------
3859
3860    procedure Gather_Components
3861      (Typ           : Entity_Id;
3862       Comp_List     : Node_Id;
3863       Governed_By   : List_Id;
3864       Into          : Elist_Id;
3865       Report_Errors : out Boolean)
3866    is
3867       Assoc           : Node_Id;
3868       Variant         : Node_Id;
3869       Discrete_Choice : Node_Id;
3870       Comp_Item       : Node_Id;
3871
3872       Discrim       : Entity_Id;
3873       Discrim_Name  : Node_Id;
3874       Discrim_Value : Node_Id;
3875
3876    begin
3877       Report_Errors := False;
3878
3879       if No (Comp_List) or else Null_Present (Comp_List) then
3880          return;
3881
3882       elsif Present (Component_Items (Comp_List)) then
3883          Comp_Item := First (Component_Items (Comp_List));
3884
3885       else
3886          Comp_Item := Empty;
3887       end if;
3888
3889       while Present (Comp_Item) loop
3890
3891          --  Skip the tag of a tagged record, the interface tags, as well
3892          --  as all items that are not user components (anonymous types,
3893          --  rep clauses, Parent field, controller field).
3894
3895          if Nkind (Comp_Item) = N_Component_Declaration then
3896             declare
3897                Comp : constant Entity_Id := Defining_Identifier (Comp_Item);
3898             begin
3899                if not Is_Tag (Comp)
3900                  and then Chars (Comp) /= Name_uParent
3901                  and then Chars (Comp) /= Name_uController
3902                then
3903                   Append_Elmt (Comp, Into);
3904                end if;
3905             end;
3906          end if;
3907
3908          Next (Comp_Item);
3909       end loop;
3910
3911       if No (Variant_Part (Comp_List)) then
3912          return;
3913       else
3914          Discrim_Name := Name (Variant_Part (Comp_List));
3915          Variant := First_Non_Pragma (Variants (Variant_Part (Comp_List)));
3916       end if;
3917
3918       --  Look for the discriminant that governs this variant part.
3919       --  The discriminant *must* be in the Governed_By List
3920
3921       Assoc := First (Governed_By);
3922       Find_Constraint : loop
3923          Discrim := First (Choices (Assoc));
3924          exit Find_Constraint when Chars (Discrim_Name) = Chars (Discrim)
3925            or else (Present (Corresponding_Discriminant (Entity (Discrim)))
3926                       and then
3927                     Chars (Corresponding_Discriminant (Entity (Discrim)))
3928                          = Chars  (Discrim_Name))
3929            or else Chars (Original_Record_Component (Entity (Discrim)))
3930                          = Chars (Discrim_Name);
3931
3932          if No (Next (Assoc)) then
3933             if not Is_Constrained (Typ)
3934               and then Is_Derived_Type (Typ)
3935               and then Present (Stored_Constraint (Typ))
3936             then
3937                --  If the type is a tagged type with inherited discriminants,
3938                --  use the stored constraint on the parent in order to find
3939                --  the values of discriminants that are otherwise hidden by an
3940                --  explicit constraint. Renamed discriminants are handled in
3941                --  the code above.
3942
3943                --  If several parent discriminants are renamed by a single
3944                --  discriminant of the derived type, the call to obtain the
3945                --  Corresponding_Discriminant field only retrieves the last
3946                --  of them. We recover the constraint on the others from the
3947                --  Stored_Constraint as well.
3948
3949                declare
3950                   D : Entity_Id;
3951                   C : Elmt_Id;
3952
3953                begin
3954                   D := First_Discriminant (Etype (Typ));
3955                   C := First_Elmt (Stored_Constraint (Typ));
3956                   while Present (D) and then Present (C) loop
3957                      if Chars (Discrim_Name) = Chars (D) then
3958                         if Is_Entity_Name (Node (C))
3959                           and then Entity (Node (C)) = Entity (Discrim)
3960                         then
3961                            --  D is renamed by Discrim, whose value is given in
3962                            --  Assoc.
3963
3964                            null;
3965
3966                         else
3967                            Assoc :=
3968                              Make_Component_Association (Sloc (Typ),
3969                                New_List
3970                                  (New_Occurrence_Of (D, Sloc (Typ))),
3971                                   Duplicate_Subexpr_No_Checks (Node (C)));
3972                         end if;
3973                         exit Find_Constraint;
3974                      end if;
3975
3976                      Next_Discriminant (D);
3977                      Next_Elmt (C);
3978                   end loop;
3979                end;
3980             end if;
3981          end if;
3982
3983          if No (Next (Assoc)) then
3984             Error_Msg_NE (" missing value for discriminant&",
3985               First (Governed_By), Discrim_Name);
3986             Report_Errors := True;
3987             return;
3988          end if;
3989
3990          Next (Assoc);
3991       end loop Find_Constraint;
3992
3993       Discrim_Value := Expression (Assoc);
3994
3995       if not Is_OK_Static_Expression (Discrim_Value) then
3996          Error_Msg_FE
3997            ("value for discriminant & must be static!",
3998             Discrim_Value, Discrim);
3999          Why_Not_Static (Discrim_Value);
4000          Report_Errors := True;
4001          return;
4002       end if;
4003
4004       Search_For_Discriminant_Value : declare
4005          Low  : Node_Id;
4006          High : Node_Id;
4007
4008          UI_High          : Uint;
4009          UI_Low           : Uint;
4010          UI_Discrim_Value : constant Uint := Expr_Value (Discrim_Value);
4011
4012       begin
4013          Find_Discrete_Value : while Present (Variant) loop
4014             Discrete_Choice := First (Discrete_Choices (Variant));
4015             while Present (Discrete_Choice) loop
4016
4017                exit Find_Discrete_Value when
4018                  Nkind (Discrete_Choice) = N_Others_Choice;
4019
4020                Get_Index_Bounds (Discrete_Choice, Low, High);
4021
4022                UI_Low  := Expr_Value (Low);
4023                UI_High := Expr_Value (High);
4024
4025                exit Find_Discrete_Value when
4026                  UI_Low <= UI_Discrim_Value
4027                    and then
4028                  UI_High >= UI_Discrim_Value;
4029
4030                Next (Discrete_Choice);
4031             end loop;
4032
4033             Next_Non_Pragma (Variant);
4034          end loop Find_Discrete_Value;
4035       end Search_For_Discriminant_Value;
4036
4037       if No (Variant) then
4038          Error_Msg_NE
4039            ("value of discriminant & is out of range", Discrim_Value, Discrim);
4040          Report_Errors := True;
4041          return;
4042       end  if;
4043
4044       --  If we have found the corresponding choice, recursively add its
4045       --  components to the Into list.
4046
4047       Gather_Components (Empty,
4048         Component_List (Variant), Governed_By, Into, Report_Errors);
4049    end Gather_Components;
4050
4051    ------------------------
4052    -- Get_Actual_Subtype --
4053    ------------------------
4054
4055    function Get_Actual_Subtype (N : Node_Id) return Entity_Id is
4056       Typ  : constant Entity_Id := Etype (N);
4057       Utyp : Entity_Id := Underlying_Type (Typ);
4058       Decl : Node_Id;
4059       Atyp : Entity_Id;
4060
4061    begin
4062       if No (Utyp) then
4063          Utyp := Typ;
4064       end if;
4065
4066       --  If what we have is an identifier that references a subprogram
4067       --  formal, or a variable or constant object, then we get the actual
4068       --  subtype from the referenced entity if one has been built.
4069
4070       if Nkind (N) = N_Identifier
4071         and then
4072           (Is_Formal (Entity (N))
4073             or else Ekind (Entity (N)) = E_Constant
4074             or else Ekind (Entity (N)) = E_Variable)
4075         and then Present (Actual_Subtype (Entity (N)))
4076       then
4077          return Actual_Subtype (Entity (N));
4078
4079       --  Actual subtype of unchecked union is always itself. We never need
4080       --  the "real" actual subtype. If we did, we couldn't get it anyway
4081       --  because the discriminant is not available. The restrictions on
4082       --  Unchecked_Union are designed to make sure that this is OK.
4083
4084       elsif Is_Unchecked_Union (Base_Type (Utyp)) then
4085          return Typ;
4086
4087       --  Here for the unconstrained case, we must find actual subtype
4088       --  No actual subtype is available, so we must build it on the fly.
4089
4090       --  Checking the type, not the underlying type, for constrainedness
4091       --  seems to be necessary. Maybe all the tests should be on the type???
4092
4093       elsif (not Is_Constrained (Typ))
4094            and then (Is_Array_Type (Utyp)
4095                       or else (Is_Record_Type (Utyp)
4096                                 and then Has_Discriminants (Utyp)))
4097            and then not Has_Unknown_Discriminants (Utyp)
4098            and then not (Ekind (Utyp) = E_String_Literal_Subtype)
4099       then
4100          --  Nothing to do if in spec expression (why not???)
4101
4102          if In_Spec_Expression then
4103             return Typ;
4104
4105          elsif Is_Private_Type (Typ)
4106            and then not Has_Discriminants (Typ)
4107          then
4108             --  If the type has no discriminants, there is no subtype to
4109             --  build, even if the underlying type is discriminated.
4110
4111             return Typ;
4112
4113          --  Else build the actual subtype
4114
4115          else
4116             Decl := Build_Actual_Subtype (Typ, N);
4117             Atyp := Defining_Identifier (Decl);
4118
4119             --  If Build_Actual_Subtype generated a new declaration then use it
4120
4121             if Atyp /= Typ then
4122
4123                --  The actual subtype is an Itype, so analyze the declaration,
4124                --  but do not attach it to the tree, to get the type defined.
4125
4126                Set_Parent (Decl, N);
4127                Set_Is_Itype (Atyp);
4128                Analyze (Decl, Suppress => All_Checks);
4129                Set_Associated_Node_For_Itype (Atyp, N);
4130                Set_Has_Delayed_Freeze (Atyp, False);
4131
4132                --  We need to freeze the actual subtype immediately. This is
4133                --  needed, because otherwise this Itype will not get frozen
4134                --  at all, and it is always safe to freeze on creation because
4135                --  any associated types must be frozen at this point.
4136
4137                Freeze_Itype (Atyp, N);
4138                return Atyp;
4139
4140             --  Otherwise we did not build a declaration, so return original
4141
4142             else
4143                return Typ;
4144             end if;
4145          end if;
4146
4147       --  For all remaining cases, the actual subtype is the same as
4148       --  the nominal type.
4149
4150       else
4151          return Typ;
4152       end if;
4153    end Get_Actual_Subtype;
4154
4155    -------------------------------------
4156    -- Get_Actual_Subtype_If_Available --
4157    -------------------------------------
4158
4159    function Get_Actual_Subtype_If_Available (N : Node_Id) return Entity_Id is
4160       Typ  : constant Entity_Id := Etype (N);
4161
4162    begin
4163       --  If what we have is an identifier that references a subprogram
4164       --  formal, or a variable or constant object, then we get the actual
4165       --  subtype from the referenced entity if one has been built.
4166
4167       if Nkind (N) = N_Identifier
4168         and then
4169           (Is_Formal (Entity (N))
4170             or else Ekind (Entity (N)) = E_Constant
4171             or else Ekind (Entity (N)) = E_Variable)
4172         and then Present (Actual_Subtype (Entity (N)))
4173       then
4174          return Actual_Subtype (Entity (N));
4175
4176       --  Otherwise the Etype of N is returned unchanged
4177
4178       else
4179          return Typ;
4180       end if;
4181    end Get_Actual_Subtype_If_Available;
4182
4183    -------------------------------
4184    -- Get_Default_External_Name --
4185    -------------------------------
4186
4187    function Get_Default_External_Name (E : Node_Or_Entity_Id) return Node_Id is
4188    begin
4189       Get_Decoded_Name_String (Chars (E));
4190
4191       if Opt.External_Name_Imp_Casing = Uppercase then
4192          Set_Casing (All_Upper_Case);
4193       else
4194          Set_Casing (All_Lower_Case);
4195       end if;
4196
4197       return
4198         Make_String_Literal (Sloc (E),
4199           Strval => String_From_Name_Buffer);
4200    end Get_Default_External_Name;
4201
4202    ---------------------------
4203    -- Get_Enum_Lit_From_Pos --
4204    ---------------------------
4205
4206    function Get_Enum_Lit_From_Pos
4207      (T   : Entity_Id;
4208       Pos : Uint;
4209       Loc : Source_Ptr) return Node_Id
4210    is
4211       Lit : Node_Id;
4212
4213    begin
4214       --  In the case where the literal is of type Character, Wide_Character
4215       --  or Wide_Wide_Character or of a type derived from them, there needs
4216       --  to be some special handling since there is no explicit chain of
4217       --  literals to search. Instead, an N_Character_Literal node is created
4218       --  with the appropriate Char_Code and Chars fields.
4219
4220       if Is_Standard_Character_Type (T) then
4221          Set_Character_Literal_Name (UI_To_CC (Pos));
4222          return
4223            Make_Character_Literal (Loc,
4224              Chars              => Name_Find,
4225              Char_Literal_Value => Pos);
4226
4227       --  For all other cases, we have a complete table of literals, and
4228       --  we simply iterate through the chain of literal until the one
4229       --  with the desired position value is found.
4230       --
4231
4232       else
4233          Lit := First_Literal (Base_Type (T));
4234          for J in 1 .. UI_To_Int (Pos) loop
4235             Next_Literal (Lit);
4236          end loop;
4237
4238          return New_Occurrence_Of (Lit, Loc);
4239       end if;
4240    end Get_Enum_Lit_From_Pos;
4241
4242    ------------------------
4243    -- Get_Generic_Entity --
4244    ------------------------
4245
4246    function Get_Generic_Entity (N : Node_Id) return Entity_Id is
4247       Ent : constant Entity_Id := Entity (Name (N));
4248    begin
4249       if Present (Renamed_Object (Ent)) then
4250          return Renamed_Object (Ent);
4251       else
4252          return Ent;
4253       end if;
4254    end Get_Generic_Entity;
4255
4256    ----------------------
4257    -- Get_Index_Bounds --
4258    ----------------------
4259
4260    procedure Get_Index_Bounds (N : Node_Id; L, H : out Node_Id) is
4261       Kind : constant Node_Kind := Nkind (N);
4262       R    : Node_Id;
4263
4264    begin
4265       if Kind = N_Range then
4266          L := Low_Bound (N);
4267          H := High_Bound (N);
4268
4269       elsif Kind = N_Subtype_Indication then
4270          R := Range_Expression (Constraint (N));
4271
4272          if R = Error then
4273             L := Error;
4274             H := Error;
4275             return;
4276
4277          else
4278             L := Low_Bound  (Range_Expression (Constraint (N)));
4279             H := High_Bound (Range_Expression (Constraint (N)));
4280          end if;
4281
4282       elsif Is_Entity_Name (N) and then Is_Type (Entity (N)) then
4283          if Error_Posted (Scalar_Range (Entity (N))) then
4284             L := Error;
4285             H := Error;
4286
4287          elsif Nkind (Scalar_Range (Entity (N))) = N_Subtype_Indication then
4288             Get_Index_Bounds (Scalar_Range (Entity (N)), L, H);
4289
4290          else
4291             L := Low_Bound  (Scalar_Range (Entity (N)));
4292             H := High_Bound (Scalar_Range (Entity (N)));
4293          end if;
4294
4295       else
4296          --  N is an expression, indicating a range with one value
4297
4298          L := N;
4299          H := N;
4300       end if;
4301    end Get_Index_Bounds;
4302
4303    ----------------------------------
4304    -- Get_Library_Unit_Name_string --
4305    ----------------------------------
4306
4307    procedure Get_Library_Unit_Name_String (Decl_Node : Node_Id) is
4308       Unit_Name_Id : constant Unit_Name_Type := Get_Unit_Name (Decl_Node);
4309
4310    begin
4311       Get_Unit_Name_String (Unit_Name_Id);
4312
4313       --  Remove seven last character (" (spec)" or " (body)")
4314
4315       Name_Len := Name_Len - 7;
4316       pragma Assert (Name_Buffer (Name_Len + 1) = ' ');
4317    end Get_Library_Unit_Name_String;
4318
4319    ------------------------
4320    -- Get_Name_Entity_Id --
4321    ------------------------
4322
4323    function Get_Name_Entity_Id (Id : Name_Id) return Entity_Id is
4324    begin
4325       return Entity_Id (Get_Name_Table_Info (Id));
4326    end Get_Name_Entity_Id;
4327
4328    -------------------
4329    -- Get_Pragma_Id --
4330    -------------------
4331
4332    function Get_Pragma_Id (N : Node_Id) return Pragma_Id is
4333    begin
4334       return Get_Pragma_Id (Pragma_Name (N));
4335    end Get_Pragma_Id;
4336
4337    ---------------------------
4338    -- Get_Referenced_Object --
4339    ---------------------------
4340
4341    function Get_Referenced_Object (N : Node_Id) return Node_Id is
4342       R : Node_Id;
4343
4344    begin
4345       R := N;
4346       while Is_Entity_Name (R)
4347         and then Present (Renamed_Object (Entity (R)))
4348       loop
4349          R := Renamed_Object (Entity (R));
4350       end loop;
4351
4352       return R;
4353    end Get_Referenced_Object;
4354
4355    ------------------------
4356    -- Get_Renamed_Entity --
4357    ------------------------
4358
4359    function Get_Renamed_Entity (E : Entity_Id) return Entity_Id is
4360       R : Entity_Id;
4361
4362    begin
4363       R := E;
4364       while Present (Renamed_Entity (R)) loop
4365          R := Renamed_Entity (R);
4366       end loop;
4367
4368       return R;
4369    end Get_Renamed_Entity;
4370
4371    -------------------------
4372    -- Get_Subprogram_Body --
4373    -------------------------
4374
4375    function Get_Subprogram_Body (E : Entity_Id) return Node_Id is
4376       Decl : Node_Id;
4377
4378    begin
4379       Decl := Unit_Declaration_Node (E);
4380
4381       if Nkind (Decl) = N_Subprogram_Body then
4382          return Decl;
4383
4384       --  The below comment is bad, because it is possible for
4385       --  Nkind (Decl) to be an N_Subprogram_Body_Stub ???
4386
4387       else           --  Nkind (Decl) = N_Subprogram_Declaration
4388
4389          if Present (Corresponding_Body (Decl)) then
4390             return Unit_Declaration_Node (Corresponding_Body (Decl));
4391
4392          --  Imported subprogram case
4393
4394          else
4395             return Empty;
4396          end if;
4397       end if;
4398    end Get_Subprogram_Body;
4399
4400    ---------------------------
4401    -- Get_Subprogram_Entity --
4402    ---------------------------
4403
4404    function Get_Subprogram_Entity (Nod : Node_Id) return Entity_Id is
4405       Nam  : Node_Id;
4406       Proc : Entity_Id;
4407
4408    begin
4409       if Nkind (Nod) = N_Accept_Statement then
4410          Nam := Entry_Direct_Name (Nod);
4411
4412       --  For an entry call, the prefix of the call is a selected component.
4413       --  Need additional code for internal calls ???
4414
4415       elsif Nkind (Nod) = N_Entry_Call_Statement then
4416          if Nkind (Name (Nod)) = N_Selected_Component then
4417             Nam := Entity (Selector_Name (Name (Nod)));
4418          else
4419             Nam := Empty;
4420          end if;
4421
4422       else
4423          Nam := Name (Nod);
4424       end if;
4425
4426       if Nkind (Nam) = N_Explicit_Dereference then
4427          Proc := Etype (Prefix (Nam));
4428       elsif Is_Entity_Name (Nam) then
4429          Proc := Entity (Nam);
4430       else
4431          return Empty;
4432       end if;
4433
4434       if Is_Object (Proc) then
4435          Proc := Etype (Proc);
4436       end if;
4437
4438       if Ekind (Proc) = E_Access_Subprogram_Type then
4439          Proc := Directly_Designated_Type (Proc);
4440       end if;
4441
4442       if not Is_Subprogram (Proc)
4443         and then Ekind (Proc) /= E_Subprogram_Type
4444       then
4445          return Empty;
4446       else
4447          return Proc;
4448       end if;
4449    end Get_Subprogram_Entity;
4450
4451    -----------------------------
4452    -- Get_Task_Body_Procedure --
4453    -----------------------------
4454
4455    function Get_Task_Body_Procedure (E : Entity_Id) return Node_Id is
4456    begin
4457       --  Note: A task type may be the completion of a private type with
4458       --  discriminants. When performing elaboration checks on a task
4459       --  declaration, the current view of the type may be the private one,
4460       --  and the procedure that holds the body of the task is held in its
4461       --  underlying type.
4462
4463       --  This is an odd function, why not have Task_Body_Procedure do
4464       --  the following digging???
4465
4466       return Task_Body_Procedure (Underlying_Type (Root_Type (E)));
4467    end Get_Task_Body_Procedure;
4468
4469    -----------------------
4470    -- Has_Access_Values --
4471    -----------------------
4472
4473    function Has_Access_Values (T : Entity_Id) return Boolean is
4474       Typ : constant Entity_Id := Underlying_Type (T);
4475
4476    begin
4477       --  Case of a private type which is not completed yet. This can only
4478       --  happen in the case of a generic format type appearing directly, or
4479       --  as a component of the type to which this function is being applied
4480       --  at the top level. Return False in this case, since we certainly do
4481       --  not know that the type contains access types.
4482
4483       if No (Typ) then
4484          return False;
4485
4486       elsif Is_Access_Type (Typ) then
4487          return True;
4488
4489       elsif Is_Array_Type (Typ) then
4490          return Has_Access_Values (Component_Type (Typ));
4491
4492       elsif Is_Record_Type (Typ) then
4493          declare
4494             Comp : Entity_Id;
4495
4496          begin
4497             --  Loop to Check components
4498
4499             Comp := First_Component_Or_Discriminant (Typ);
4500             while Present (Comp) loop
4501
4502                --  Check for access component, tag field does not count, even
4503                --  though it is implemented internally using an access type.
4504
4505                if Has_Access_Values (Etype (Comp))
4506                  and then Chars (Comp) /= Name_uTag
4507                then
4508                   return True;
4509                end if;
4510
4511                Next_Component_Or_Discriminant (Comp);
4512             end loop;
4513          end;
4514
4515          return False;
4516
4517       else
4518          return False;
4519       end if;
4520    end Has_Access_Values;
4521
4522    ------------------------------
4523    -- Has_Compatible_Alignment --
4524    ------------------------------
4525
4526    function Has_Compatible_Alignment
4527      (Obj  : Entity_Id;
4528       Expr : Node_Id) return Alignment_Result
4529    is
4530       function Has_Compatible_Alignment_Internal
4531         (Obj     : Entity_Id;
4532          Expr    : Node_Id;
4533          Default : Alignment_Result) return Alignment_Result;
4534       --  This is the internal recursive function that actually does the work.
4535       --  There is one additional parameter, which says what the result should
4536       --  be if no alignment information is found, and there is no definite
4537       --  indication of compatible alignments. At the outer level, this is set
4538       --  to Unknown, but for internal recursive calls in the case where types
4539       --  are known to be correct, it is set to Known_Compatible.
4540
4541       ---------------------------------------
4542       -- Has_Compatible_Alignment_Internal --
4543       ---------------------------------------
4544
4545       function Has_Compatible_Alignment_Internal
4546         (Obj     : Entity_Id;
4547          Expr    : Node_Id;
4548          Default : Alignment_Result) return Alignment_Result
4549       is
4550          Result : Alignment_Result := Known_Compatible;
4551          --  Holds the current status of the result. Note that once a value of
4552          --  Known_Incompatible is set, it is sticky and does not get changed
4553          --  to Unknown (the value in Result only gets worse as we go along,
4554          --  never better).
4555
4556          Offs : Uint := No_Uint;
4557          --  Set to a factor of the offset from the base object when Expr is a
4558          --  selected or indexed component, based on Component_Bit_Offset and
4559          --  Component_Size respectively. A negative value is used to represent
4560          --  a value which is not known at compile time.
4561
4562          procedure Check_Prefix;
4563          --  Checks the prefix recursively in the case where the expression
4564          --  is an indexed or selected component.
4565
4566          procedure Set_Result (R : Alignment_Result);
4567          --  If R represents a worse outcome (unknown instead of known
4568          --  compatible, or known incompatible), then set Result to R.
4569
4570          ------------------
4571          -- Check_Prefix --
4572          ------------------
4573
4574          procedure Check_Prefix is
4575          begin
4576             --  The subtlety here is that in doing a recursive call to check
4577             --  the prefix, we have to decide what to do in the case where we
4578             --  don't find any specific indication of an alignment problem.
4579
4580             --  At the outer level, we normally set Unknown as the result in
4581             --  this case, since we can only set Known_Compatible if we really
4582             --  know that the alignment value is OK, but for the recursive
4583             --  call, in the case where the types match, and we have not
4584             --  specified a peculiar alignment for the object, we are only
4585             --  concerned about suspicious rep clauses, the default case does
4586             --  not affect us, since the compiler will, in the absence of such
4587             --  rep clauses, ensure that the alignment is correct.
4588
4589             if Default = Known_Compatible
4590               or else
4591                 (Etype (Obj) = Etype (Expr)
4592                   and then (Unknown_Alignment (Obj)
4593                              or else
4594                                Alignment (Obj) = Alignment (Etype (Obj))))
4595             then
4596                Set_Result
4597                  (Has_Compatible_Alignment_Internal
4598                     (Obj, Prefix (Expr), Known_Compatible));
4599
4600             --  In all other cases, we need a full check on the prefix
4601
4602             else
4603                Set_Result
4604                  (Has_Compatible_Alignment_Internal
4605                     (Obj, Prefix (Expr), Unknown));
4606             end if;
4607          end Check_Prefix;
4608
4609          ----------------
4610          -- Set_Result --
4611          ----------------
4612
4613          procedure Set_Result (R : Alignment_Result) is
4614          begin
4615             if R > Result then
4616                Result := R;
4617             end if;
4618          end Set_Result;
4619
4620       --  Start of processing for Has_Compatible_Alignment_Internal
4621
4622       begin
4623          --  If Expr is a selected component, we must make sure there is no
4624          --  potentially troublesome component clause, and that the record is
4625          --  not packed.
4626
4627          if Nkind (Expr) = N_Selected_Component then
4628
4629             --  Packed record always generate unknown alignment
4630
4631             if Is_Packed (Etype (Prefix (Expr))) then
4632                Set_Result (Unknown);
4633             end if;
4634
4635             --  Check prefix and component offset
4636
4637             Check_Prefix;
4638             Offs := Component_Bit_Offset (Entity (Selector_Name (Expr)));
4639
4640          --  If Expr is an indexed component, we must make sure there is no
4641          --  potentially troublesome Component_Size clause and that the array
4642          --  is not bit-packed.
4643
4644          elsif Nkind (Expr) = N_Indexed_Component then
4645             declare
4646                Typ : constant Entity_Id := Etype (Prefix (Expr));
4647                Ind : constant Node_Id   := First_Index (Typ);
4648
4649             begin
4650                --  Bit packed array always generates unknown alignment
4651
4652                if Is_Bit_Packed_Array (Typ) then
4653                   Set_Result (Unknown);
4654                end if;
4655
4656                --  Check prefix and component offset
4657
4658                Check_Prefix;
4659                Offs := Component_Size (Typ);
4660
4661                --  Small optimization: compute the full offset when possible
4662
4663                if Offs /= No_Uint
4664                  and then Offs > Uint_0
4665                  and then Present (Ind)
4666                  and then Nkind (Ind) = N_Range
4667                  and then Compile_Time_Known_Value (Low_Bound (Ind))
4668                  and then Compile_Time_Known_Value (First (Expressions (Expr)))
4669                then
4670                   Offs := Offs * (Expr_Value (First (Expressions (Expr)))
4671                                     - Expr_Value (Low_Bound ((Ind))));
4672                end if;
4673             end;
4674          end if;
4675
4676          --  If we have a null offset, the result is entirely determined by
4677          --  the base object and has already been computed recursively.
4678
4679          if Offs = Uint_0 then
4680             null;
4681
4682          --  Case where we know the alignment of the object
4683
4684          elsif Known_Alignment (Obj) then
4685             declare
4686                ObjA : constant Uint := Alignment (Obj);
4687                ExpA : Uint          := No_Uint;
4688                SizA : Uint          := No_Uint;
4689
4690             begin
4691                --  If alignment of Obj is 1, then we are always OK
4692
4693                if ObjA = 1 then
4694                   Set_Result (Known_Compatible);
4695
4696                --  Alignment of Obj is greater than 1, so we need to check
4697
4698                else
4699                   --  If we have an offset, see if it is compatible
4700
4701                   if Offs /= No_Uint and Offs > Uint_0 then
4702                      if Offs mod (System_Storage_Unit * ObjA) /= 0 then
4703                         Set_Result (Known_Incompatible);
4704                      end if;
4705
4706                      --  See if Expr is an object with known alignment
4707
4708                   elsif Is_Entity_Name (Expr)
4709                     and then Known_Alignment (Entity (Expr))
4710                   then
4711                      ExpA := Alignment (Entity (Expr));
4712
4713                      --  Otherwise, we can use the alignment of the type of
4714                      --  Expr given that we already checked for
4715                      --  discombobulating rep clauses for the cases of indexed
4716                      --  and selected components above.
4717
4718                   elsif Known_Alignment (Etype (Expr)) then
4719                      ExpA := Alignment (Etype (Expr));
4720
4721                      --  Otherwise the alignment is unknown
4722
4723                   else
4724                      Set_Result (Default);
4725                   end if;
4726
4727                   --  If we got an alignment, see if it is acceptable
4728
4729                   if ExpA /= No_Uint and then ExpA < ObjA then
4730                      Set_Result (Known_Incompatible);
4731                   end if;
4732
4733                   --  If Expr is not a piece of a larger object, see if size
4734                   --  is given. If so, check that it is not too small for the
4735                   --  required alignment.
4736
4737                   if Offs /= No_Uint then
4738                      null;
4739
4740                      --  See if Expr is an object with known size
4741
4742                   elsif Is_Entity_Name (Expr)
4743                     and then Known_Static_Esize (Entity (Expr))
4744                   then
4745                      SizA := Esize (Entity (Expr));
4746
4747                      --  Otherwise, we check the object size of the Expr type
4748
4749                   elsif Known_Static_Esize (Etype (Expr)) then
4750                      SizA := Esize (Etype (Expr));
4751                   end if;
4752
4753                   --  If we got a size, see if it is a multiple of the Obj
4754                   --  alignment, if not, then the alignment cannot be
4755                   --  acceptable, since the size is always a multiple of the
4756                   --  alignment.
4757
4758                   if SizA /= No_Uint then
4759                      if SizA mod (ObjA * Ttypes.System_Storage_Unit) /= 0 then
4760                         Set_Result (Known_Incompatible);
4761                      end if;
4762                   end if;
4763                end if;
4764             end;
4765
4766          --  If we do not know required alignment, any non-zero offset is a
4767          --  potential problem (but certainly may be OK, so result is unknown).
4768
4769          elsif Offs /= No_Uint then
4770             Set_Result (Unknown);
4771
4772          --  If we can't find the result by direct comparison of alignment
4773          --  values, then there is still one case that we can determine known
4774          --  result, and that is when we can determine that the types are the
4775          --  same, and no alignments are specified. Then we known that the
4776          --  alignments are compatible, even if we don't know the alignment
4777          --  value in the front end.
4778
4779          elsif Etype (Obj) = Etype (Expr) then
4780
4781             --  Types are the same, but we have to check for possible size
4782             --  and alignments on the Expr object that may make the alignment
4783             --  different, even though the types are the same.
4784
4785             if Is_Entity_Name (Expr) then
4786
4787                --  First check alignment of the Expr object. Any alignment less
4788                --  than Maximum_Alignment is worrisome since this is the case
4789                --  where we do not know the alignment of Obj.
4790
4791                if Known_Alignment (Entity (Expr))
4792                  and then
4793                    UI_To_Int (Alignment (Entity (Expr))) <
4794                                                     Ttypes.Maximum_Alignment
4795                then
4796                   Set_Result (Unknown);
4797
4798                   --  Now check size of Expr object. Any size that is not an
4799                   --  even multiple of Maximum_Alignment is also worrisome
4800                   --  since it may cause the alignment of the object to be less
4801                   --  than the alignment of the type.
4802
4803                elsif Known_Static_Esize (Entity (Expr))
4804                  and then
4805                    (UI_To_Int (Esize (Entity (Expr))) mod
4806                      (Ttypes.Maximum_Alignment * Ttypes.System_Storage_Unit))
4807                                                                         /= 0
4808                then
4809                   Set_Result (Unknown);
4810
4811                   --  Otherwise same type is decisive
4812
4813                else
4814                   Set_Result (Known_Compatible);
4815                end if;
4816             end if;
4817
4818          --  Another case to deal with is when there is an explicit size or
4819          --  alignment clause when the types are not the same. If so, then the
4820          --  result is Unknown. We don't need to do this test if the Default is
4821          --  Unknown, since that result will be set in any case.
4822
4823          elsif Default /= Unknown
4824            and then (Has_Size_Clause      (Etype (Expr))
4825                       or else
4826                      Has_Alignment_Clause (Etype (Expr)))
4827          then
4828             Set_Result (Unknown);
4829
4830          --  If no indication found, set default
4831
4832          else
4833             Set_Result (Default);
4834          end if;
4835
4836          --  Return worst result found
4837
4838          return Result;
4839       end Has_Compatible_Alignment_Internal;
4840
4841    --  Start of processing for Has_Compatible_Alignment
4842
4843    begin
4844       --  If Obj has no specified alignment, then set alignment from the type
4845       --  alignment. Perhaps we should always do this, but for sure we should
4846       --  do it when there is an address clause since we can do more if the
4847       --  alignment is known.
4848
4849       if Unknown_Alignment (Obj) then
4850          Set_Alignment (Obj, Alignment (Etype (Obj)));
4851       end if;
4852
4853       --  Now do the internal call that does all the work
4854
4855       return Has_Compatible_Alignment_Internal (Obj, Expr, Unknown);
4856    end Has_Compatible_Alignment;
4857
4858    ----------------------
4859    -- Has_Declarations --
4860    ----------------------
4861
4862    function Has_Declarations (N : Node_Id) return Boolean is
4863    begin
4864       return Nkind_In (Nkind (N), N_Accept_Statement,
4865                                   N_Block_Statement,
4866                                   N_Compilation_Unit_Aux,
4867                                   N_Entry_Body,
4868                                   N_Package_Body,
4869                                   N_Protected_Body,
4870                                   N_Subprogram_Body,
4871                                   N_Task_Body,
4872                                   N_Package_Specification);
4873    end Has_Declarations;
4874
4875    -------------------------------------------
4876    -- Has_Discriminant_Dependent_Constraint --
4877    -------------------------------------------
4878
4879    function Has_Discriminant_Dependent_Constraint
4880      (Comp : Entity_Id) return Boolean
4881    is
4882       Comp_Decl  : constant Node_Id := Parent (Comp);
4883       Subt_Indic : constant Node_Id :=
4884                      Subtype_Indication (Component_Definition (Comp_Decl));
4885       Constr     : Node_Id;
4886       Assn       : Node_Id;
4887
4888    begin
4889       if Nkind (Subt_Indic) = N_Subtype_Indication then
4890          Constr := Constraint (Subt_Indic);
4891
4892          if Nkind (Constr) = N_Index_Or_Discriminant_Constraint then
4893             Assn := First (Constraints (Constr));
4894             while Present (Assn) loop
4895                case Nkind (Assn) is
4896                   when N_Subtype_Indication |
4897                        N_Range              |
4898                        N_Identifier
4899                   =>
4900                      if Depends_On_Discriminant (Assn) then
4901                         return True;
4902                      end if;
4903
4904                   when N_Discriminant_Association =>
4905                      if Depends_On_Discriminant (Expression (Assn)) then
4906                         return True;
4907                      end if;
4908
4909                   when others =>
4910                      null;
4911
4912                end case;
4913
4914                Next (Assn);
4915             end loop;
4916          end if;
4917       end if;
4918
4919       return False;
4920    end Has_Discriminant_Dependent_Constraint;
4921
4922    --------------------
4923    -- Has_Infinities --
4924    --------------------
4925
4926    function Has_Infinities (E : Entity_Id) return Boolean is
4927    begin
4928       return
4929         Is_Floating_Point_Type (E)
4930           and then Nkind (Scalar_Range (E)) = N_Range
4931           and then Includes_Infinities (Scalar_Range (E));
4932    end Has_Infinities;
4933
4934    --------------------
4935    -- Has_Interfaces --
4936    --------------------
4937
4938    function Has_Interfaces
4939      (T             : Entity_Id;
4940       Use_Full_View : Boolean := True) return Boolean
4941    is
4942       Typ : Entity_Id := Base_Type (T);
4943
4944    begin
4945       --  Handle concurrent types
4946
4947       if Is_Concurrent_Type (Typ) then
4948          Typ := Corresponding_Record_Type (Typ);
4949       end if;
4950
4951       if not Present (Typ)
4952         or else not Is_Record_Type (Typ)
4953         or else not Is_Tagged_Type (Typ)
4954       then
4955          return False;
4956       end if;
4957
4958       --  Handle private types
4959
4960       if Use_Full_View
4961         and then Present (Full_View (Typ))
4962       then
4963          Typ := Full_View (Typ);
4964       end if;
4965
4966       --  Handle concurrent record types
4967
4968       if Is_Concurrent_Record_Type (Typ)
4969         and then Is_Non_Empty_List (Abstract_Interface_List (Typ))
4970       then
4971          return True;
4972       end if;
4973
4974       loop
4975          if Is_Interface (Typ)
4976            or else
4977              (Is_Record_Type (Typ)
4978                and then Present (Interfaces (Typ))
4979                and then not Is_Empty_Elmt_List (Interfaces (Typ)))
4980          then
4981             return True;
4982          end if;
4983
4984          exit when Etype (Typ) = Typ
4985
4986             --  Handle private types
4987
4988             or else (Present (Full_View (Etype (Typ)))
4989                        and then Full_View (Etype (Typ)) = Typ)
4990
4991             --  Protect the frontend against wrong source with cyclic
4992             --  derivations
4993
4994             or else Etype (Typ) = T;
4995
4996          --  Climb to the ancestor type handling private types
4997
4998          if Present (Full_View (Etype (Typ))) then
4999             Typ := Full_View (Etype (Typ));
5000          else
5001             Typ := Etype (Typ);
5002          end if;
5003       end loop;
5004
5005       return False;
5006    end Has_Interfaces;
5007
5008    ------------------------
5009    -- Has_Null_Exclusion --
5010    ------------------------
5011
5012    function Has_Null_Exclusion (N : Node_Id) return Boolean is
5013    begin
5014       case Nkind (N) is
5015          when N_Access_Definition               |
5016               N_Access_Function_Definition      |
5017               N_Access_Procedure_Definition     |
5018               N_Access_To_Object_Definition     |
5019               N_Allocator                       |
5020               N_Derived_Type_Definition         |
5021               N_Function_Specification          |
5022               N_Subtype_Declaration             =>
5023             return Null_Exclusion_Present (N);
5024
5025          when N_Component_Definition            |
5026               N_Formal_Object_Declaration       |
5027               N_Object_Renaming_Declaration     =>
5028             if Present (Subtype_Mark (N)) then
5029                return Null_Exclusion_Present (N);
5030             else pragma Assert (Present (Access_Definition (N)));
5031                return Null_Exclusion_Present (Access_Definition (N));
5032             end if;
5033
5034          when N_Discriminant_Specification =>
5035             if Nkind (Discriminant_Type (N)) = N_Access_Definition then
5036                return Null_Exclusion_Present (Discriminant_Type (N));
5037             else
5038                return Null_Exclusion_Present (N);
5039             end if;
5040
5041          when N_Object_Declaration =>
5042             if Nkind (Object_Definition (N)) = N_Access_Definition then
5043                return Null_Exclusion_Present (Object_Definition (N));
5044             else
5045                return Null_Exclusion_Present (N);
5046             end if;
5047
5048          when N_Parameter_Specification =>
5049             if Nkind (Parameter_Type (N)) = N_Access_Definition then
5050                return Null_Exclusion_Present (Parameter_Type (N));
5051             else
5052                return Null_Exclusion_Present (N);
5053             end if;
5054
5055          when others =>
5056             return False;
5057
5058       end case;
5059    end Has_Null_Exclusion;
5060
5061    ------------------------
5062    -- Has_Null_Extension --
5063    ------------------------
5064
5065    function Has_Null_Extension (T : Entity_Id) return Boolean is
5066       B     : constant Entity_Id := Base_Type (T);
5067       Comps : Node_Id;
5068       Ext   : Node_Id;
5069
5070    begin
5071       if Nkind (Parent (B)) = N_Full_Type_Declaration
5072         and then Present (Record_Extension_Part (Type_Definition (Parent (B))))
5073       then
5074          Ext := Record_Extension_Part (Type_Definition (Parent (B)));
5075
5076          if Present (Ext) then
5077             if Null_Present (Ext) then
5078                return True;
5079             else
5080                Comps := Component_List (Ext);
5081
5082                --  The null component list is rewritten during analysis to
5083                --  include the parent component. Any other component indicates
5084                --  that the extension was not originally null.
5085
5086                return Null_Present (Comps)
5087                  or else No (Next (First (Component_Items (Comps))));
5088             end if;
5089          else
5090             return False;
5091          end if;
5092
5093       else
5094          return False;
5095       end if;
5096    end Has_Null_Extension;
5097
5098    -------------------------------
5099    -- Has_Overriding_Initialize --
5100    -------------------------------
5101
5102    function Has_Overriding_Initialize (T : Entity_Id) return Boolean is
5103       BT   : constant Entity_Id := Base_Type (T);
5104       P    : Elmt_Id;
5105
5106    begin
5107       if Is_Controlled (BT) then
5108          if Is_RTU (Scope (BT), Ada_Finalization) then
5109             return False;
5110
5111          elsif Present (Primitive_Operations (BT)) then
5112             P := First_Elmt (Primitive_Operations (BT));
5113             while Present (P) loop
5114                declare
5115                   Init : constant Entity_Id := Node (P);
5116                   Formal : constant Entity_Id := First_Formal (Init);
5117                begin
5118                   if Ekind (Init) = E_Procedure
5119                        and then Chars (Init) = Name_Initialize
5120                        and then Comes_From_Source (Init)
5121                        and then Present (Formal)
5122                        and then Etype (Formal) = BT
5123                        and then No (Next_Formal (Formal))
5124                        and then (Ada_Version < Ada_2012
5125                                    or else not Null_Present (Parent (Init)))
5126                   then
5127                      return True;
5128                   end if;
5129                end;
5130
5131                Next_Elmt (P);
5132             end loop;
5133          end if;
5134
5135          --  Here if type itself does not have a non-null Initialize operation:
5136          --  check immediate ancestor.
5137
5138          if Is_Derived_Type (BT)
5139            and then Has_Overriding_Initialize (Etype (BT))
5140          then
5141             return True;
5142          end if;
5143       end if;
5144
5145       return False;
5146    end Has_Overriding_Initialize;
5147
5148    --------------------------------------
5149    -- Has_Preelaborable_Initialization --
5150    --------------------------------------
5151
5152    function Has_Preelaborable_Initialization (E : Entity_Id) return Boolean is
5153       Has_PE : Boolean;
5154
5155       procedure Check_Components (E : Entity_Id);
5156       --  Check component/discriminant chain, sets Has_PE False if a component
5157       --  or discriminant does not meet the preelaborable initialization rules.
5158
5159       ----------------------
5160       -- Check_Components --
5161       ----------------------
5162
5163       procedure Check_Components (E : Entity_Id) is
5164          Ent : Entity_Id;
5165          Exp : Node_Id;
5166
5167          function Is_Preelaborable_Expression (N : Node_Id) return Boolean;
5168          --  Returns True if and only if the expression denoted by N does not
5169          --  violate restrictions on preelaborable constructs (RM-10.2.1(5-9)).
5170
5171          ---------------------------------
5172          -- Is_Preelaborable_Expression --
5173          ---------------------------------
5174
5175          function Is_Preelaborable_Expression (N : Node_Id) return Boolean is
5176             Exp           : Node_Id;
5177             Assn          : Node_Id;
5178             Choice        : Node_Id;
5179             Comp_Type     : Entity_Id;
5180             Is_Array_Aggr : Boolean;
5181
5182          begin
5183             if Is_Static_Expression (N) then
5184                return True;
5185
5186             elsif Nkind (N) = N_Null then
5187                return True;
5188
5189             --  Attributes are allowed in general, even if their prefix is a
5190             --  formal type. (It seems that certain attributes known not to be
5191             --  static might not be allowed, but there are no rules to prevent
5192             --  them.)
5193
5194             elsif Nkind (N) = N_Attribute_Reference then
5195                return True;
5196
5197             --  The name of a discriminant evaluated within its parent type is
5198             --  defined to be preelaborable (10.2.1(8)). Note that we test for
5199             --  names that denote discriminals as well as discriminants to
5200             --  catch references occurring within init procs.
5201
5202             elsif Is_Entity_Name (N)
5203               and then
5204                 (Ekind (Entity (N)) = E_Discriminant
5205                   or else
5206                     ((Ekind (Entity (N)) = E_Constant
5207                        or else Ekind (Entity (N)) = E_In_Parameter)
5208                      and then Present (Discriminal_Link (Entity (N)))))
5209             then
5210                return True;
5211
5212             elsif Nkind (N) = N_Qualified_Expression then
5213                return Is_Preelaborable_Expression (Expression (N));
5214
5215             --  For aggregates we have to check that each of the associations
5216             --  is preelaborable.
5217
5218             elsif Nkind (N) = N_Aggregate
5219               or else Nkind (N) = N_Extension_Aggregate
5220             then
5221                Is_Array_Aggr := Is_Array_Type (Etype (N));
5222
5223                if Is_Array_Aggr then
5224                   Comp_Type := Component_Type (Etype (N));
5225                end if;
5226
5227                --  Check the ancestor part of extension aggregates, which must
5228                --  be either the name of a type that has preelaborable init or
5229                --  an expression that is preelaborable.
5230
5231                if Nkind (N) = N_Extension_Aggregate then
5232                   declare
5233                      Anc_Part : constant Node_Id := Ancestor_Part (N);
5234
5235                   begin
5236                      if Is_Entity_Name (Anc_Part)
5237                        and then Is_Type (Entity (Anc_Part))
5238                      then
5239                         if not Has_Preelaborable_Initialization
5240                                  (Entity (Anc_Part))
5241                         then
5242                            return False;
5243                         end if;
5244
5245                      elsif not Is_Preelaborable_Expression (Anc_Part) then
5246                         return False;
5247                      end if;
5248                   end;
5249                end if;
5250
5251                --  Check positional associations
5252
5253                Exp := First (Expressions (N));
5254                while Present (Exp) loop
5255                   if not Is_Preelaborable_Expression (Exp) then
5256                      return False;
5257                   end if;
5258
5259                   Next (Exp);
5260                end loop;
5261
5262                --  Check named associations
5263
5264                Assn := First (Component_Associations (N));
5265                while Present (Assn) loop
5266                   Choice := First (Choices (Assn));
5267                   while Present (Choice) loop
5268                      if Is_Array_Aggr then
5269                         if Nkind (Choice) = N_Others_Choice then
5270                            null;
5271
5272                         elsif Nkind (Choice) = N_Range then
5273                            if not Is_Static_Range (Choice) then
5274                               return False;
5275                            end if;
5276
5277                         elsif not Is_Static_Expression (Choice) then
5278                            return False;
5279                         end if;
5280
5281                      else
5282                         Comp_Type := Etype (Choice);
5283                      end if;
5284
5285                      Next (Choice);
5286                   end loop;
5287
5288                   --  If the association has a <> at this point, then we have
5289                   --  to check whether the component's type has preelaborable
5290                   --  initialization. Note that this only occurs when the
5291                   --  association's corresponding component does not have a
5292                   --  default expression, the latter case having already been
5293                   --  expanded as an expression for the association.
5294
5295                   if Box_Present (Assn) then
5296                      if not Has_Preelaborable_Initialization (Comp_Type) then
5297                         return False;
5298                      end if;
5299
5300                   --  In the expression case we check whether the expression
5301                   --  is preelaborable.
5302
5303                   elsif
5304                     not Is_Preelaborable_Expression (Expression (Assn))
5305                   then
5306                      return False;
5307                   end if;
5308
5309                   Next (Assn);
5310                end loop;
5311
5312                --  If we get here then aggregate as a whole is preelaborable
5313
5314                return True;
5315
5316             --  All other cases are not preelaborable
5317
5318             else
5319                return False;
5320             end if;
5321          end Is_Preelaborable_Expression;
5322
5323       --  Start of processing for Check_Components
5324
5325       begin
5326          --  Loop through entities of record or protected type
5327
5328          Ent := E;
5329          while Present (Ent) loop
5330
5331             --  We are interested only in components and discriminants
5332
5333             Exp := Empty;
5334
5335             case Ekind (Ent) is
5336                when E_Component =>
5337
5338                   --  Get default expression if any. If there is no declaration
5339                   --  node, it means we have an internal entity. The parent and
5340                   --  tag fields are examples of such entities. For such cases,
5341                   --  we just test the type of the entity.
5342
5343                   if Present (Declaration_Node (Ent)) then
5344                      Exp := Expression (Declaration_Node (Ent));
5345                   end if;
5346
5347                when E_Discriminant =>
5348
5349                   --  Note: for a renamed discriminant, the Declaration_Node
5350                   --  may point to the one from the ancestor, and have a
5351                   --  different expression, so use the proper attribute to
5352                   --  retrieve the expression from the derived constraint.
5353
5354                   Exp := Discriminant_Default_Value (Ent);
5355
5356                when others =>
5357                   goto Check_Next_Entity;
5358             end case;
5359
5360             --  A component has PI if it has no default expression and the
5361             --  component type has PI.
5362
5363             if No (Exp) then
5364                if not Has_Preelaborable_Initialization (Etype (Ent)) then
5365                   Has_PE := False;
5366                   exit;
5367                end if;
5368
5369             --  Require the default expression to be preelaborable
5370
5371             elsif not Is_Preelaborable_Expression (Exp) then
5372                Has_PE := False;
5373                exit;
5374             end if;
5375
5376          <<Check_Next_Entity>>
5377             Next_Entity (Ent);
5378          end loop;
5379       end Check_Components;
5380
5381    --  Start of processing for Has_Preelaborable_Initialization
5382
5383    begin
5384       --  Immediate return if already marked as known preelaborable init. This
5385       --  covers types for which this function has already been called once
5386       --  and returned True (in which case the result is cached), and also
5387       --  types to which a pragma Preelaborable_Initialization applies.
5388
5389       if Known_To_Have_Preelab_Init (E) then
5390          return True;
5391       end if;
5392
5393       --  If the type is a subtype representing a generic actual type, then
5394       --  test whether its base type has preelaborable initialization since
5395       --  the subtype representing the actual does not inherit this attribute
5396       --  from the actual or formal. (but maybe it should???)
5397
5398       if Is_Generic_Actual_Type (E) then
5399          return Has_Preelaborable_Initialization (Base_Type (E));
5400       end if;
5401
5402       --  All elementary types have preelaborable initialization
5403
5404       if Is_Elementary_Type (E) then
5405          Has_PE := True;
5406
5407       --  Array types have PI if the component type has PI
5408
5409       elsif Is_Array_Type (E) then
5410          Has_PE := Has_Preelaborable_Initialization (Component_Type (E));
5411
5412       --  A derived type has preelaborable initialization if its parent type
5413       --  has preelaborable initialization and (in the case of a derived record
5414       --  extension) if the non-inherited components all have preelaborable
5415       --  initialization. However, a user-defined controlled type with an
5416       --  overriding Initialize procedure does not have preelaborable
5417       --  initialization.
5418
5419       elsif Is_Derived_Type (E) then
5420
5421          --  If the derived type is a private extension then it doesn't have
5422          --  preelaborable initialization.
5423
5424          if Ekind (Base_Type (E)) = E_Record_Type_With_Private then
5425             return False;
5426          end if;
5427
5428          --  First check whether ancestor type has preelaborable initialization
5429
5430          Has_PE := Has_Preelaborable_Initialization (Etype (Base_Type (E)));
5431
5432          --  If OK, check extension components (if any)
5433
5434          if Has_PE and then Is_Record_Type (E) then
5435             Check_Components (First_Entity (E));
5436          end if;
5437
5438          --  Check specifically for 10.2.1(11.4/2) exception: a controlled type
5439          --  with a user defined Initialize procedure does not have PI.
5440
5441          if Has_PE
5442            and then Is_Controlled (E)
5443            and then Has_Overriding_Initialize (E)
5444          then
5445             Has_PE := False;
5446          end if;
5447
5448       --  Private types not derived from a type having preelaborable init and
5449       --  that are not marked with pragma Preelaborable_Initialization do not
5450       --  have preelaborable initialization.
5451
5452       elsif Is_Private_Type (E) then
5453          return False;
5454
5455       --  Record type has PI if it is non private and all components have PI
5456
5457       elsif Is_Record_Type (E) then
5458          Has_PE := True;
5459          Check_Components (First_Entity (E));
5460
5461       --  Protected types must not have entries, and components must meet
5462       --  same set of rules as for record components.
5463
5464       elsif Is_Protected_Type (E) then
5465          if Has_Entries (E) then
5466             Has_PE := False;
5467          else
5468             Has_PE := True;
5469             Check_Components (First_Entity (E));
5470             Check_Components (First_Private_Entity (E));
5471          end if;
5472
5473       --  Type System.Address always has preelaborable initialization
5474
5475       elsif Is_RTE (E, RE_Address) then
5476          Has_PE := True;
5477
5478       --  In all other cases, type does not have preelaborable initialization
5479
5480       else
5481          return False;
5482       end if;
5483
5484       --  If type has preelaborable initialization, cache result
5485
5486       if Has_PE then
5487          Set_Known_To_Have_Preelab_Init (E);
5488       end if;
5489
5490       return Has_PE;
5491    end Has_Preelaborable_Initialization;
5492
5493    ---------------------------
5494    -- Has_Private_Component --
5495    ---------------------------
5496
5497    function Has_Private_Component (Type_Id : Entity_Id) return Boolean is
5498       Btype     : Entity_Id := Base_Type (Type_Id);
5499       Component : Entity_Id;
5500
5501    begin
5502       if Error_Posted (Type_Id)
5503         or else Error_Posted (Btype)
5504       then
5505          return False;
5506       end if;
5507
5508       if Is_Class_Wide_Type (Btype) then
5509          Btype := Root_Type (Btype);
5510       end if;
5511
5512       if Is_Private_Type (Btype) then
5513          declare
5514             UT : constant Entity_Id := Underlying_Type (Btype);
5515          begin
5516             if No (UT) then
5517                if No (Full_View (Btype)) then
5518                   return not Is_Generic_Type (Btype)
5519                     and then not Is_Generic_Type (Root_Type (Btype));
5520                else
5521                   return not Is_Generic_Type (Root_Type (Full_View (Btype)));
5522                end if;
5523             else
5524                return not Is_Frozen (UT) and then Has_Private_Component (UT);
5525             end if;
5526          end;
5527
5528       elsif Is_Array_Type (Btype) then
5529          return Has_Private_Component (Component_Type (Btype));
5530
5531       elsif Is_Record_Type (Btype) then
5532          Component := First_Component (Btype);
5533          while Present (Component) loop
5534             if Has_Private_Component (Etype (Component)) then
5535                return True;
5536             end if;
5537
5538             Next_Component (Component);
5539          end loop;
5540
5541          return False;
5542
5543       elsif Is_Protected_Type (Btype)
5544         and then Present (Corresponding_Record_Type (Btype))
5545       then
5546          return Has_Private_Component (Corresponding_Record_Type (Btype));
5547
5548       else
5549          return False;
5550       end if;
5551    end Has_Private_Component;
5552
5553    -----------------------------
5554    -- Has_Static_Array_Bounds --
5555    -----------------------------
5556
5557    function Has_Static_Array_Bounds (Typ : Node_Id) return Boolean is
5558       Ndims : constant Nat := Number_Dimensions (Typ);
5559
5560       Index : Node_Id;
5561       Low   : Node_Id;
5562       High  : Node_Id;
5563
5564    begin
5565       --  Unconstrained types do not have static bounds
5566
5567       if not Is_Constrained (Typ) then
5568          return False;
5569       end if;
5570
5571       --  First treat specially string literals, as the lower bound and length
5572       --  of string literals are not stored like those of arrays.
5573
5574       --  A string literal always has static bounds
5575
5576       if Ekind (Typ) = E_String_Literal_Subtype then
5577          return True;
5578       end if;
5579
5580       --  Treat all dimensions in turn
5581
5582       Index := First_Index (Typ);
5583       for Indx in 1 .. Ndims loop
5584
5585          --  In case of an erroneous index which is not a discrete type, return
5586          --  that the type is not static.
5587
5588          if not Is_Discrete_Type (Etype (Index))
5589            or else Etype (Index) = Any_Type
5590          then
5591             return False;
5592          end if;
5593
5594          Get_Index_Bounds (Index, Low, High);
5595
5596          if Error_Posted (Low) or else Error_Posted (High) then
5597             return False;
5598          end if;
5599
5600          if         Is_OK_Static_Expression (Low)
5601            and then Is_OK_Static_Expression (High)
5602          then
5603             null;
5604          else
5605             return False;
5606          end if;
5607
5608          Next (Index);
5609       end loop;
5610
5611       --  If we fall through the loop, all indexes matched
5612
5613       return True;
5614    end Has_Static_Array_Bounds;
5615
5616    ----------------
5617    -- Has_Stream --
5618    ----------------
5619
5620    function Has_Stream (T : Entity_Id) return Boolean is
5621       E : Entity_Id;
5622
5623    begin
5624       if No (T) then
5625          return False;
5626
5627       elsif Is_RTE (Root_Type (T), RE_Root_Stream_Type) then
5628          return True;
5629
5630       elsif Is_Array_Type (T) then
5631          return Has_Stream (Component_Type (T));
5632
5633       elsif Is_Record_Type (T) then
5634          E := First_Component (T);
5635          while Present (E) loop
5636             if Has_Stream (Etype (E)) then
5637                return True;
5638             else
5639                Next_Component (E);
5640             end if;
5641          end loop;
5642
5643          return False;
5644
5645       elsif Is_Private_Type (T) then
5646          return Has_Stream (Underlying_Type (T));
5647
5648       else
5649          return False;
5650       end if;
5651    end Has_Stream;
5652
5653    ----------------
5654    -- Has_Suffix --
5655    ----------------
5656
5657    function Has_Suffix (E : Entity_Id; Suffix : Character) return Boolean is
5658    begin
5659       Get_Name_String (Chars (E));
5660       return Name_Buffer (Name_Len) = Suffix;
5661    end Has_Suffix;
5662
5663    --------------------------
5664    -- Has_Tagged_Component --
5665    --------------------------
5666
5667    function Has_Tagged_Component (Typ : Entity_Id) return Boolean is
5668       Comp : Entity_Id;
5669
5670    begin
5671       if Is_Private_Type (Typ)
5672         and then Present (Underlying_Type (Typ))
5673       then
5674          return Has_Tagged_Component (Underlying_Type (Typ));
5675
5676       elsif Is_Array_Type (Typ) then
5677          return Has_Tagged_Component (Component_Type (Typ));
5678
5679       elsif Is_Tagged_Type (Typ) then
5680          return True;
5681
5682       elsif Is_Record_Type (Typ) then
5683          Comp := First_Component (Typ);
5684          while Present (Comp) loop
5685             if Has_Tagged_Component (Etype (Comp)) then
5686                return True;
5687             end if;
5688
5689             Next_Component (Comp);
5690          end loop;
5691
5692          return False;
5693
5694       else
5695          return False;
5696       end if;
5697    end Has_Tagged_Component;
5698
5699    -------------------------
5700    -- Implementation_Kind --
5701    -------------------------
5702
5703    function Implementation_Kind (Subp : Entity_Id) return Name_Id is
5704       Impl_Prag : constant Node_Id := Get_Rep_Pragma (Subp, Name_Implemented);
5705    begin
5706       pragma Assert (Present (Impl_Prag));
5707       return
5708         Chars (Expression (Last (Pragma_Argument_Associations (Impl_Prag))));
5709    end Implementation_Kind;
5710
5711    --------------------------
5712    -- Implements_Interface --
5713    --------------------------
5714
5715    function Implements_Interface
5716      (Typ_Ent         : Entity_Id;
5717       Iface_Ent       : Entity_Id;
5718       Exclude_Parents : Boolean := False) return Boolean
5719    is
5720       Ifaces_List : Elist_Id;
5721       Elmt        : Elmt_Id;
5722       Iface       : Entity_Id := Base_Type (Iface_Ent);
5723       Typ         : Entity_Id := Base_Type (Typ_Ent);
5724
5725    begin
5726       if Is_Class_Wide_Type (Typ) then
5727          Typ := Root_Type (Typ);
5728       end if;
5729
5730       if not Has_Interfaces (Typ) then
5731          return False;
5732       end if;
5733
5734       if Is_Class_Wide_Type (Iface) then
5735          Iface := Root_Type (Iface);
5736       end if;
5737
5738       Collect_Interfaces (Typ, Ifaces_List);
5739
5740       Elmt := First_Elmt (Ifaces_List);
5741       while Present (Elmt) loop
5742          if Is_Ancestor (Node (Elmt), Typ, Use_Full_View => True)
5743            and then Exclude_Parents
5744          then
5745             null;
5746
5747          elsif Node (Elmt) = Iface then
5748             return True;
5749          end if;
5750
5751          Next_Elmt (Elmt);
5752       end loop;
5753
5754       return False;
5755    end Implements_Interface;
5756
5757    -----------------
5758    -- In_Instance --
5759    -----------------
5760
5761    function In_Instance return Boolean is
5762       Curr_Unit : constant Entity_Id := Cunit_Entity (Current_Sem_Unit);
5763       S         : Entity_Id;
5764
5765    begin
5766       S := Current_Scope;
5767       while Present (S)
5768         and then S /= Standard_Standard
5769       loop
5770          if (Ekind (S) = E_Function
5771               or else Ekind (S) = E_Package
5772               or else Ekind (S) = E_Procedure)
5773            and then Is_Generic_Instance (S)
5774          then
5775             --  A child instance is always compiled in the context of a parent
5776             --  instance. Nevertheless, the actuals are not analyzed in an
5777             --  instance context. We detect this case by examining the current
5778             --  compilation unit, which must be a child instance, and checking
5779             --  that it is not currently on the scope stack.
5780
5781             if Is_Child_Unit (Curr_Unit)
5782               and then
5783                 Nkind (Unit (Cunit (Current_Sem_Unit)))
5784                   = N_Package_Instantiation
5785               and then not In_Open_Scopes (Curr_Unit)
5786             then
5787                return False;
5788             else
5789                return True;
5790             end if;
5791          end if;
5792
5793          S := Scope (S);
5794       end loop;
5795
5796       return False;
5797    end In_Instance;
5798
5799    ----------------------
5800    -- In_Instance_Body --
5801    ----------------------
5802
5803    function In_Instance_Body return Boolean is
5804       S : Entity_Id;
5805
5806    begin
5807       S := Current_Scope;
5808       while Present (S)
5809         and then S /= Standard_Standard
5810       loop
5811          if (Ekind (S) = E_Function
5812               or else Ekind (S) = E_Procedure)
5813            and then Is_Generic_Instance (S)
5814          then
5815             return True;
5816
5817          elsif Ekind (S) = E_Package
5818            and then In_Package_Body (S)
5819            and then Is_Generic_Instance (S)
5820          then
5821             return True;
5822          end if;
5823
5824          S := Scope (S);
5825       end loop;
5826
5827       return False;
5828    end In_Instance_Body;
5829
5830    -----------------------------
5831    -- In_Instance_Not_Visible --
5832    -----------------------------
5833
5834    function In_Instance_Not_Visible return Boolean is
5835       S : Entity_Id;
5836
5837    begin
5838       S := Current_Scope;
5839       while Present (S)
5840         and then S /= Standard_Standard
5841       loop
5842          if (Ekind (S) = E_Function
5843               or else Ekind (S) = E_Procedure)
5844            and then Is_Generic_Instance (S)
5845          then
5846             return True;
5847
5848          elsif Ekind (S) = E_Package
5849            and then (In_Package_Body (S) or else In_Private_Part (S))
5850            and then Is_Generic_Instance (S)
5851          then
5852             return True;
5853          end if;
5854
5855          S := Scope (S);
5856       end loop;
5857
5858       return False;
5859    end In_Instance_Not_Visible;
5860
5861    ------------------------------
5862    -- In_Instance_Visible_Part --
5863    ------------------------------
5864
5865    function In_Instance_Visible_Part return Boolean is
5866       S : Entity_Id;
5867
5868    begin
5869       S := Current_Scope;
5870       while Present (S)
5871         and then S /= Standard_Standard
5872       loop
5873          if Ekind (S) = E_Package
5874            and then Is_Generic_Instance (S)
5875            and then not In_Package_Body (S)
5876            and then not In_Private_Part (S)
5877          then
5878             return True;
5879          end if;
5880
5881          S := Scope (S);
5882       end loop;
5883
5884       return False;
5885    end In_Instance_Visible_Part;
5886
5887    ---------------------
5888    -- In_Package_Body --
5889    ---------------------
5890
5891    function In_Package_Body return Boolean is
5892       S : Entity_Id;
5893
5894    begin
5895       S := Current_Scope;
5896       while Present (S)
5897         and then S /= Standard_Standard
5898       loop
5899          if Ekind (S) = E_Package
5900            and then In_Package_Body (S)
5901          then
5902             return True;
5903          else
5904             S := Scope (S);
5905          end if;
5906       end loop;
5907
5908       return False;
5909    end In_Package_Body;
5910
5911    --------------------------------
5912    -- In_Parameter_Specification --
5913    --------------------------------
5914
5915    function In_Parameter_Specification (N : Node_Id) return Boolean is
5916       PN : Node_Id;
5917
5918    begin
5919       PN := Parent (N);
5920       while Present (PN) loop
5921          if Nkind (PN) = N_Parameter_Specification then
5922             return True;
5923          end if;
5924
5925          PN := Parent (PN);
5926       end loop;
5927
5928       return False;
5929    end In_Parameter_Specification;
5930
5931    --------------------------------------
5932    -- In_Subprogram_Or_Concurrent_Unit --
5933    --------------------------------------
5934
5935    function In_Subprogram_Or_Concurrent_Unit return Boolean is
5936       E : Entity_Id;
5937       K : Entity_Kind;
5938
5939    begin
5940       --  Use scope chain to check successively outer scopes
5941
5942       E := Current_Scope;
5943       loop
5944          K := Ekind (E);
5945
5946          if K in Subprogram_Kind
5947            or else K in Concurrent_Kind
5948            or else K in Generic_Subprogram_Kind
5949          then
5950             return True;
5951
5952          elsif E = Standard_Standard then
5953             return False;
5954          end if;
5955
5956          E := Scope (E);
5957       end loop;
5958    end In_Subprogram_Or_Concurrent_Unit;
5959
5960    ---------------------
5961    -- In_Visible_Part --
5962    ---------------------
5963
5964    function In_Visible_Part (Scope_Id : Entity_Id) return Boolean is
5965    begin
5966       return
5967         Is_Package_Or_Generic_Package (Scope_Id)
5968           and then In_Open_Scopes (Scope_Id)
5969           and then not In_Package_Body (Scope_Id)
5970           and then not In_Private_Part (Scope_Id);
5971    end In_Visible_Part;
5972
5973    ---------------------------------
5974    -- Insert_Explicit_Dereference --
5975    ---------------------------------
5976
5977    procedure Insert_Explicit_Dereference (N : Node_Id) is
5978       New_Prefix : constant Node_Id := Relocate_Node (N);
5979       Ent        : Entity_Id := Empty;
5980       Pref       : Node_Id;
5981       I          : Interp_Index;
5982       It         : Interp;
5983       T          : Entity_Id;
5984
5985    begin
5986       Save_Interps (N, New_Prefix);
5987
5988       Rewrite (N,
5989         Make_Explicit_Dereference (Sloc (Parent (N)),
5990           Prefix => New_Prefix));
5991
5992       Set_Etype (N, Designated_Type (Etype (New_Prefix)));
5993
5994       if Is_Overloaded (New_Prefix) then
5995
5996          --  The dereference is also overloaded, and its interpretations are
5997          --  the designated types of the interpretations of the original node.
5998
5999          Set_Etype (N, Any_Type);
6000
6001          Get_First_Interp (New_Prefix, I, It);
6002          while Present (It.Nam) loop
6003             T := It.Typ;
6004
6005             if Is_Access_Type (T) then
6006                Add_One_Interp (N, Designated_Type (T), Designated_Type (T));
6007             end if;
6008
6009             Get_Next_Interp (I, It);
6010          end loop;
6011
6012          End_Interp_List;
6013
6014       else
6015          --  Prefix is unambiguous: mark the original prefix (which might
6016          --  Come_From_Source) as a reference, since the new (relocated) one
6017          --  won't be taken into account.
6018
6019          if Is_Entity_Name (New_Prefix) then
6020             Ent := Entity (New_Prefix);
6021             Pref := New_Prefix;
6022
6023          --  For a retrieval of a subcomponent of some composite object,
6024          --  retrieve the ultimate entity if there is one.
6025
6026          elsif Nkind (New_Prefix) = N_Selected_Component
6027            or else Nkind (New_Prefix) = N_Indexed_Component
6028          then
6029             Pref := Prefix (New_Prefix);
6030             while Present (Pref)
6031               and then
6032                 (Nkind (Pref) = N_Selected_Component
6033                   or else Nkind (Pref) = N_Indexed_Component)
6034             loop
6035                Pref := Prefix (Pref);
6036             end loop;
6037
6038             if Present (Pref) and then Is_Entity_Name (Pref) then
6039                Ent := Entity (Pref);
6040             end if;
6041          end if;
6042
6043          --  Place the reference on the entity node
6044
6045          if Present (Ent) then
6046             Generate_Reference (Ent, Pref);
6047          end if;
6048       end if;
6049    end Insert_Explicit_Dereference;
6050
6051    ------------------------------------------
6052    -- Inspect_Deferred_Constant_Completion --
6053    ------------------------------------------
6054
6055    procedure Inspect_Deferred_Constant_Completion (Decls : List_Id) is
6056       Decl   : Node_Id;
6057
6058    begin
6059       Decl := First (Decls);
6060       while Present (Decl) loop
6061
6062          --  Deferred constant signature
6063
6064          if Nkind (Decl) = N_Object_Declaration
6065            and then Constant_Present (Decl)
6066            and then No (Expression (Decl))
6067
6068             --  No need to check internally generated constants
6069
6070            and then Comes_From_Source (Decl)
6071
6072             --  The constant is not completed. A full object declaration or a
6073             --  pragma Import complete a deferred constant.
6074
6075            and then not Has_Completion (Defining_Identifier (Decl))
6076          then
6077             Error_Msg_N
6078               ("constant declaration requires initialization expression",
6079               Defining_Identifier (Decl));
6080          end if;
6081
6082          Decl := Next (Decl);
6083       end loop;
6084    end Inspect_Deferred_Constant_Completion;
6085
6086    -----------------------------
6087    -- Is_Actual_Out_Parameter --
6088    -----------------------------
6089
6090    function Is_Actual_Out_Parameter (N : Node_Id) return Boolean is
6091       Formal : Entity_Id;
6092       Call   : Node_Id;
6093    begin
6094       Find_Actual (N, Formal, Call);
6095       return Present (Formal) and then Ekind (Formal) = E_Out_Parameter;
6096    end Is_Actual_Out_Parameter;
6097
6098    -------------------------
6099    -- Is_Actual_Parameter --
6100    -------------------------
6101
6102    function Is_Actual_Parameter (N : Node_Id) return Boolean is
6103       PK : constant Node_Kind := Nkind (Parent (N));
6104
6105    begin
6106       case PK is
6107          when N_Parameter_Association =>
6108             return N = Explicit_Actual_Parameter (Parent (N));
6109
6110          when N_Function_Call | N_Procedure_Call_Statement =>
6111             return Is_List_Member (N)
6112               and then
6113                 List_Containing (N) = Parameter_Associations (Parent (N));
6114
6115          when others =>
6116             return False;
6117       end case;
6118    end Is_Actual_Parameter;
6119
6120    --------------------------------
6121    -- Is_Actual_Tagged_Parameter --
6122    --------------------------------
6123
6124    function Is_Actual_Tagged_Parameter (N : Node_Id) return Boolean is
6125       Formal : Entity_Id;
6126       Call   : Node_Id;
6127    begin
6128       Find_Actual (N, Formal, Call);
6129       return Present (Formal) and then Is_Tagged_Type (Etype (Formal));
6130    end Is_Actual_Tagged_Parameter;
6131
6132    ---------------------
6133    -- Is_Aliased_View --
6134    ---------------------
6135
6136    function Is_Aliased_View (Obj : Node_Id) return Boolean is
6137       E : Entity_Id;
6138
6139    begin
6140       if Is_Entity_Name (Obj) then
6141
6142          E := Entity (Obj);
6143
6144          return
6145            (Is_Object (E)
6146              and then
6147                (Is_Aliased (E)
6148                   or else (Present (Renamed_Object (E))
6149                              and then Is_Aliased_View (Renamed_Object (E)))))
6150
6151            or else ((Is_Formal (E)
6152                       or else Ekind (E) = E_Generic_In_Out_Parameter
6153                       or else Ekind (E) = E_Generic_In_Parameter)
6154                     and then Is_Tagged_Type (Etype (E)))
6155
6156            or else (Is_Concurrent_Type (E)
6157                      and then In_Open_Scopes (E))
6158
6159             --  Current instance of type, either directly or as rewritten
6160             --  reference to the current object.
6161
6162            or else (Is_Entity_Name (Original_Node (Obj))
6163                      and then Present (Entity (Original_Node (Obj)))
6164                      and then Is_Type (Entity (Original_Node (Obj))))
6165
6166            or else (Is_Type (E) and then E = Current_Scope)
6167
6168            or else (Is_Incomplete_Or_Private_Type (E)
6169                      and then Full_View (E) = Current_Scope);
6170
6171       elsif Nkind (Obj) = N_Selected_Component then
6172          return Is_Aliased (Entity (Selector_Name (Obj)));
6173
6174       elsif Nkind (Obj) = N_Indexed_Component then
6175          return Has_Aliased_Components (Etype (Prefix (Obj)))
6176            or else
6177              (Is_Access_Type (Etype (Prefix (Obj)))
6178                and then
6179               Has_Aliased_Components
6180                 (Designated_Type (Etype (Prefix (Obj)))));
6181
6182       elsif Nkind (Obj) = N_Unchecked_Type_Conversion
6183         or else Nkind (Obj) = N_Type_Conversion
6184       then
6185          return Is_Tagged_Type (Etype (Obj))
6186            and then Is_Aliased_View (Expression (Obj));
6187
6188       elsif Nkind (Obj) = N_Explicit_Dereference then
6189          return Nkind (Original_Node (Obj)) /= N_Function_Call;
6190
6191       else
6192          return False;
6193       end if;
6194    end Is_Aliased_View;
6195
6196    -------------------------
6197    -- Is_Ancestor_Package --
6198    -------------------------
6199
6200    function Is_Ancestor_Package
6201      (E1 : Entity_Id;
6202       E2 : Entity_Id) return Boolean
6203    is
6204       Par : Entity_Id;
6205
6206    begin
6207       Par := E2;
6208       while Present (Par)
6209         and then Par /= Standard_Standard
6210       loop
6211          if Par = E1 then
6212             return True;
6213          end if;
6214
6215          Par := Scope (Par);
6216       end loop;
6217
6218       return False;
6219    end Is_Ancestor_Package;
6220
6221    ----------------------
6222    -- Is_Atomic_Object --
6223    ----------------------
6224
6225    function Is_Atomic_Object (N : Node_Id) return Boolean is
6226
6227       function Object_Has_Atomic_Components (N : Node_Id) return Boolean;
6228       --  Determines if given object has atomic components
6229
6230       function Is_Atomic_Prefix (N : Node_Id) return Boolean;
6231       --  If prefix is an implicit dereference, examine designated type
6232
6233       ----------------------
6234       -- Is_Atomic_Prefix --
6235       ----------------------
6236
6237       function Is_Atomic_Prefix (N : Node_Id) return Boolean is
6238       begin
6239          if Is_Access_Type (Etype (N)) then
6240             return
6241               Has_Atomic_Components (Designated_Type (Etype (N)));
6242          else
6243             return Object_Has_Atomic_Components (N);
6244          end if;
6245       end Is_Atomic_Prefix;
6246
6247       ----------------------------------
6248       -- Object_Has_Atomic_Components --
6249       ----------------------------------
6250
6251       function Object_Has_Atomic_Components (N : Node_Id) return Boolean is
6252       begin
6253          if Has_Atomic_Components (Etype (N))
6254            or else Is_Atomic (Etype (N))
6255          then
6256             return True;
6257
6258          elsif Is_Entity_Name (N)
6259            and then (Has_Atomic_Components (Entity (N))
6260                       or else Is_Atomic (Entity (N)))
6261          then
6262             return True;
6263
6264          elsif Nkind (N) = N_Indexed_Component
6265            or else Nkind (N) = N_Selected_Component
6266          then
6267             return Is_Atomic_Prefix (Prefix (N));
6268
6269          else
6270             return False;
6271          end if;
6272       end Object_Has_Atomic_Components;
6273
6274    --  Start of processing for Is_Atomic_Object
6275
6276    begin
6277       --  Predicate is not relevant to subprograms
6278
6279       if Is_Entity_Name (N) and then Is_Overloadable (Entity (N)) then
6280          return False;
6281
6282       elsif Is_Atomic (Etype (N))
6283         or else (Is_Entity_Name (N) and then Is_Atomic (Entity (N)))
6284       then
6285          return True;
6286
6287       elsif Nkind (N) = N_Indexed_Component
6288         or else Nkind (N) = N_Selected_Component
6289       then
6290          return Is_Atomic_Prefix (Prefix (N));
6291
6292       else
6293          return False;
6294       end if;
6295    end Is_Atomic_Object;
6296
6297    -------------------------
6298    -- Is_Coextension_Root --
6299    -------------------------
6300
6301    function Is_Coextension_Root (N : Node_Id) return Boolean is
6302    begin
6303       return
6304         Nkind (N) = N_Allocator
6305           and then Present (Coextensions (N))
6306
6307          --  Anonymous access discriminants carry a list of all nested
6308          --  controlled coextensions.
6309
6310           and then not Is_Dynamic_Coextension (N)
6311           and then not Is_Static_Coextension (N);
6312    end Is_Coextension_Root;
6313
6314    -----------------------------
6315    -- Is_Concurrent_Interface --
6316    -----------------------------
6317
6318    function Is_Concurrent_Interface (T : Entity_Id) return Boolean is
6319    begin
6320       return
6321         Is_Interface (T)
6322           and then
6323             (Is_Protected_Interface (T)
6324                or else Is_Synchronized_Interface (T)
6325                or else Is_Task_Interface (T));
6326    end Is_Concurrent_Interface;
6327
6328    --------------------------------------
6329    -- Is_Controlling_Limited_Procedure --
6330    --------------------------------------
6331
6332    function Is_Controlling_Limited_Procedure
6333      (Proc_Nam : Entity_Id) return Boolean
6334    is
6335       Param_Typ : Entity_Id := Empty;
6336
6337    begin
6338       if Ekind (Proc_Nam) = E_Procedure
6339         and then Present (Parameter_Specifications (Parent (Proc_Nam)))
6340       then
6341          Param_Typ := Etype (Parameter_Type (First (
6342                         Parameter_Specifications (Parent (Proc_Nam)))));
6343
6344       --  In this case where an Itype was created, the procedure call has been
6345       --  rewritten.
6346
6347       elsif Present (Associated_Node_For_Itype (Proc_Nam))
6348         and then Present (Original_Node (Associated_Node_For_Itype (Proc_Nam)))
6349         and then
6350           Present (Parameter_Associations
6351                      (Associated_Node_For_Itype (Proc_Nam)))
6352       then
6353          Param_Typ :=
6354            Etype (First (Parameter_Associations
6355                           (Associated_Node_For_Itype (Proc_Nam))));
6356       end if;
6357
6358       if Present (Param_Typ) then
6359          return
6360            Is_Interface (Param_Typ)
6361              and then Is_Limited_Record (Param_Typ);
6362       end if;
6363
6364       return False;
6365    end Is_Controlling_Limited_Procedure;
6366
6367    -----------------------------
6368    -- Is_CPP_Constructor_Call --
6369    -----------------------------
6370
6371    function Is_CPP_Constructor_Call (N : Node_Id) return Boolean is
6372    begin
6373       return Nkind (N) = N_Function_Call
6374         and then Is_CPP_Class (Etype (Etype (N)))
6375         and then Is_Constructor (Entity (Name (N)))
6376         and then Is_Imported (Entity (Name (N)));
6377    end Is_CPP_Constructor_Call;
6378
6379    -----------------
6380    -- Is_Delegate --
6381    -----------------
6382
6383    function Is_Delegate (T : Entity_Id) return Boolean is
6384       Desig_Type : Entity_Id;
6385
6386    begin
6387       if VM_Target /= CLI_Target then
6388          return False;
6389       end if;
6390
6391       --  Access-to-subprograms are delegates in CIL
6392
6393       if Ekind (T) = E_Access_Subprogram_Type then
6394          return True;
6395       end if;
6396
6397       if Ekind (T) not in Access_Kind then
6398
6399          --  A delegate is a managed pointer. If no designated type is defined
6400          --  it means that it's not a delegate.
6401
6402          return False;
6403       end if;
6404
6405       Desig_Type := Etype (Directly_Designated_Type (T));
6406
6407       if not Is_Tagged_Type (Desig_Type) then
6408          return False;
6409       end if;
6410
6411       --  Test if the type is inherited from [mscorlib]System.Delegate
6412
6413       while Etype (Desig_Type) /= Desig_Type loop
6414          if Chars (Scope (Desig_Type)) /= No_Name
6415            and then Is_Imported (Scope (Desig_Type))
6416            and then Get_Name_String (Chars (Scope (Desig_Type))) = "delegate"
6417          then
6418             return True;
6419          end if;
6420
6421          Desig_Type := Etype (Desig_Type);
6422       end loop;
6423
6424       return False;
6425    end Is_Delegate;
6426
6427    ----------------------------------------------
6428    -- Is_Dependent_Component_Of_Mutable_Object --
6429    ----------------------------------------------
6430
6431    function Is_Dependent_Component_Of_Mutable_Object
6432      (Object : Node_Id) return Boolean
6433    is
6434       P           : Node_Id;
6435       Prefix_Type : Entity_Id;
6436       P_Aliased   : Boolean := False;
6437       Comp        : Entity_Id;
6438
6439       function Is_Declared_Within_Variant (Comp : Entity_Id) return Boolean;
6440       --  Returns True if and only if Comp is declared within a variant part
6441
6442       --------------------------------
6443       -- Is_Declared_Within_Variant --
6444       --------------------------------
6445
6446       function Is_Declared_Within_Variant (Comp : Entity_Id) return Boolean is
6447          Comp_Decl : constant Node_Id   := Parent (Comp);
6448          Comp_List : constant Node_Id   := Parent (Comp_Decl);
6449       begin
6450          return Nkind (Parent (Comp_List)) = N_Variant;
6451       end Is_Declared_Within_Variant;
6452
6453    --  Start of processing for Is_Dependent_Component_Of_Mutable_Object
6454
6455    begin
6456       if Is_Variable (Object) then
6457
6458          if Nkind (Object) = N_Selected_Component then
6459             P := Prefix (Object);
6460             Prefix_Type := Etype (P);
6461
6462             if Is_Entity_Name (P) then
6463
6464                if Ekind (Entity (P)) = E_Generic_In_Out_Parameter then
6465                   Prefix_Type := Base_Type (Prefix_Type);
6466                end if;
6467
6468                if Is_Aliased (Entity (P)) then
6469                   P_Aliased := True;
6470                end if;
6471
6472             --  A discriminant check on a selected component may be expanded
6473             --  into a dereference when removing side-effects. Recover the
6474             --  original node and its type, which may be unconstrained.
6475
6476             elsif Nkind (P) = N_Explicit_Dereference
6477               and then not (Comes_From_Source (P))
6478             then
6479                P := Original_Node (P);
6480                Prefix_Type := Etype (P);
6481
6482             else
6483                --  Check for prefix being an aliased component???
6484
6485                null;
6486
6487             end if;
6488
6489             --  A heap object is constrained by its initial value
6490
6491             --  Ada 2005 (AI-363): Always assume the object could be mutable in
6492             --  the dereferenced case, since the access value might denote an
6493             --  unconstrained aliased object, whereas in Ada 95 the designated
6494             --  object is guaranteed to be constrained. A worst-case assumption
6495             --  has to apply in Ada 2005 because we can't tell at compile time
6496             --  whether the object is "constrained by its initial value"
6497             --  (despite the fact that 3.10.2(26/2) and 8.5.1(5/2) are
6498             --  semantic rules -- these rules are acknowledged to need fixing).
6499
6500             if Ada_Version < Ada_2005 then
6501                if Is_Access_Type (Prefix_Type)
6502                  or else Nkind (P) = N_Explicit_Dereference
6503                then
6504                   return False;
6505                end if;
6506
6507             elsif Ada_Version >= Ada_2005 then
6508                if Is_Access_Type (Prefix_Type) then
6509
6510                   --  If the access type is pool-specific, and there is no
6511                   --  constrained partial view of the designated type, then the
6512                   --  designated object is known to be constrained.
6513
6514                   if Ekind (Prefix_Type) = E_Access_Type
6515                     and then not Has_Constrained_Partial_View
6516                                    (Designated_Type (Prefix_Type))
6517                   then
6518                      return False;
6519
6520                   --  Otherwise (general access type, or there is a constrained
6521                   --  partial view of the designated type), we need to check
6522                   --  based on the designated type.
6523
6524                   else
6525                      Prefix_Type := Designated_Type (Prefix_Type);
6526                   end if;
6527                end if;
6528             end if;
6529
6530             Comp :=
6531               Original_Record_Component (Entity (Selector_Name (Object)));
6532
6533             --  As per AI-0017, the renaming is illegal in a generic body, even
6534             --  if the subtype is indefinite.
6535
6536             --  Ada 2005 (AI-363): In Ada 2005 an aliased object can be mutable
6537
6538             if not Is_Constrained (Prefix_Type)
6539               and then (not Is_Indefinite_Subtype (Prefix_Type)
6540                          or else
6541                           (Is_Generic_Type (Prefix_Type)
6542                             and then Ekind (Current_Scope) = E_Generic_Package
6543                             and then In_Package_Body (Current_Scope)))
6544
6545               and then (Is_Declared_Within_Variant (Comp)
6546                           or else Has_Discriminant_Dependent_Constraint (Comp))
6547               and then (not P_Aliased or else Ada_Version >= Ada_2005)
6548             then
6549                return True;
6550
6551             else
6552                return
6553                  Is_Dependent_Component_Of_Mutable_Object (Prefix (Object));
6554
6555             end if;
6556
6557          elsif Nkind (Object) = N_Indexed_Component
6558            or else Nkind (Object) = N_Slice
6559          then
6560             return Is_Dependent_Component_Of_Mutable_Object (Prefix (Object));
6561
6562          --  A type conversion that Is_Variable is a view conversion:
6563          --  go back to the denoted object.
6564
6565          elsif Nkind (Object) = N_Type_Conversion then
6566             return
6567               Is_Dependent_Component_Of_Mutable_Object (Expression (Object));
6568          end if;
6569       end if;
6570
6571       return False;
6572    end Is_Dependent_Component_Of_Mutable_Object;
6573
6574    ---------------------
6575    -- Is_Dereferenced --
6576    ---------------------
6577
6578    function Is_Dereferenced (N : Node_Id) return Boolean is
6579       P : constant Node_Id := Parent (N);
6580    begin
6581       return
6582          (Nkind (P) = N_Selected_Component
6583             or else
6584           Nkind (P) = N_Explicit_Dereference
6585             or else
6586           Nkind (P) = N_Indexed_Component
6587             or else
6588           Nkind (P) = N_Slice)
6589         and then Prefix (P) = N;
6590    end Is_Dereferenced;
6591
6592    ----------------------
6593    -- Is_Descendent_Of --
6594    ----------------------
6595
6596    function Is_Descendent_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
6597       T    : Entity_Id;
6598       Etyp : Entity_Id;
6599
6600    begin
6601       pragma Assert (Nkind (T1) in N_Entity);
6602       pragma Assert (Nkind (T2) in N_Entity);
6603
6604       T := Base_Type (T1);
6605
6606       --  Immediate return if the types match
6607
6608       if T = T2 then
6609          return True;
6610
6611       --  Comment needed here ???
6612
6613       elsif Ekind (T) = E_Class_Wide_Type then
6614          return Etype (T) = T2;
6615
6616       --  All other cases
6617
6618       else
6619          loop
6620             Etyp := Etype (T);
6621
6622             --  Done if we found the type we are looking for
6623
6624             if Etyp = T2 then
6625                return True;
6626
6627             --  Done if no more derivations to check
6628
6629             elsif T = T1
6630               or else T = Etyp
6631             then
6632                return False;
6633
6634             --  Following test catches error cases resulting from prev errors
6635
6636             elsif No (Etyp) then
6637                return False;
6638
6639             elsif Is_Private_Type (T) and then Etyp = Full_View (T) then
6640                return False;
6641
6642             elsif Is_Private_Type (Etyp) and then Full_View (Etyp) = T then
6643                return False;
6644             end if;
6645
6646             T := Base_Type (Etyp);
6647          end loop;
6648       end if;
6649    end Is_Descendent_Of;
6650
6651    ----------------------------
6652    -- Is_Expression_Function --
6653    ----------------------------
6654
6655    function Is_Expression_Function (Subp : Entity_Id) return Boolean is
6656       Decl : constant Node_Id := Unit_Declaration_Node (Subp);
6657
6658    begin
6659       return Ekind (Subp) = E_Function
6660         and then Nkind (Decl) = N_Subprogram_Declaration
6661         and then
6662           (Nkind (Original_Node (Decl)) = N_Expression_Function
6663             or else
6664               (Present (Corresponding_Body (Decl))
6665                 and then
6666                   Nkind (Original_Node
6667                      (Unit_Declaration_Node (Corresponding_Body (Decl))))
6668                  = N_Expression_Function));
6669    end Is_Expression_Function;
6670
6671    --------------
6672    -- Is_False --
6673    --------------
6674
6675    function Is_False (U : Uint) return Boolean is
6676    begin
6677       return (U = 0);
6678    end Is_False;
6679
6680    ---------------------------
6681    -- Is_Fixed_Model_Number --
6682    ---------------------------
6683
6684    function Is_Fixed_Model_Number (U : Ureal; T : Entity_Id) return Boolean is
6685       S : constant Ureal := Small_Value (T);
6686       M : Urealp.Save_Mark;
6687       R : Boolean;
6688    begin
6689       M := Urealp.Mark;
6690       R := (U = UR_Trunc (U / S) * S);
6691       Urealp.Release (M);
6692       return R;
6693    end Is_Fixed_Model_Number;
6694
6695    -------------------------------
6696    -- Is_Fully_Initialized_Type --
6697    -------------------------------
6698
6699    function Is_Fully_Initialized_Type (Typ : Entity_Id) return Boolean is
6700    begin
6701       if Is_Scalar_Type (Typ) then
6702          return False;
6703
6704       elsif Is_Access_Type (Typ) then
6705          return True;
6706
6707       elsif Is_Array_Type (Typ) then
6708          if Is_Fully_Initialized_Type (Component_Type (Typ)) then
6709             return True;
6710          end if;
6711
6712          --  An interesting case, if we have a constrained type one of whose
6713          --  bounds is known to be null, then there are no elements to be
6714          --  initialized, so all the elements are initialized!
6715
6716          if Is_Constrained (Typ) then
6717             declare
6718                Indx     : Node_Id;
6719                Indx_Typ : Entity_Id;
6720                Lbd, Hbd : Node_Id;
6721
6722             begin
6723                Indx := First_Index (Typ);
6724                while Present (Indx) loop
6725                   if Etype (Indx) = Any_Type then
6726                      return False;
6727
6728                   --  If index is a range, use directly
6729
6730                   elsif Nkind (Indx) = N_Range then
6731                      Lbd := Low_Bound  (Indx);
6732                      Hbd := High_Bound (Indx);
6733
6734                   else
6735                      Indx_Typ := Etype (Indx);
6736
6737                      if Is_Private_Type (Indx_Typ)  then
6738                         Indx_Typ := Full_View (Indx_Typ);
6739                      end if;
6740
6741                      if No (Indx_Typ) or else Etype (Indx_Typ) = Any_Type then
6742                         return False;
6743                      else
6744                         Lbd := Type_Low_Bound  (Indx_Typ);
6745                         Hbd := Type_High_Bound (Indx_Typ);
6746                      end if;
6747                   end if;
6748
6749                   if Compile_Time_Known_Value (Lbd)
6750                     and then Compile_Time_Known_Value (Hbd)
6751                   then
6752                      if Expr_Value (Hbd) < Expr_Value (Lbd) then
6753                         return True;
6754                      end if;
6755                   end if;
6756
6757                   Next_Index (Indx);
6758                end loop;
6759             end;
6760          end if;
6761
6762          --  If no null indexes, then type is not fully initialized
6763
6764          return False;
6765
6766       --  Record types
6767
6768       elsif Is_Record_Type (Typ) then
6769          if Has_Discriminants (Typ)
6770            and then
6771              Present (Discriminant_Default_Value (First_Discriminant (Typ)))
6772            and then Is_Fully_Initialized_Variant (Typ)
6773          then
6774             return True;
6775          end if;
6776
6777          --  Controlled records are considered to be fully initialized if
6778          --  there is a user defined Initialize routine. This may not be
6779          --  entirely correct, but as the spec notes, we are guessing here
6780          --  what is best from the point of view of issuing warnings.
6781
6782          if Is_Controlled (Typ) then
6783             declare
6784                Utyp : constant Entity_Id := Underlying_Type (Typ);
6785
6786             begin
6787                if Present (Utyp) then
6788                   declare
6789                      Init : constant Entity_Id :=
6790                               (Find_Prim_Op
6791                                  (Underlying_Type (Typ), Name_Initialize));
6792
6793                   begin
6794                      if Present (Init)
6795                        and then Comes_From_Source (Init)
6796                        and then not
6797                          Is_Predefined_File_Name
6798                            (File_Name (Get_Source_File_Index (Sloc (Init))))
6799                      then
6800                         return True;
6801
6802                      elsif Has_Null_Extension (Typ)
6803                         and then
6804                           Is_Fully_Initialized_Type
6805                             (Etype (Base_Type (Typ)))
6806                      then
6807                         return True;
6808                      end if;
6809                   end;
6810                end if;
6811             end;
6812          end if;
6813
6814          --  Otherwise see if all record components are initialized
6815
6816          declare
6817             Ent : Entity_Id;
6818
6819          begin
6820             Ent := First_Entity (Typ);
6821             while Present (Ent) loop
6822                if Chars (Ent) = Name_uController then
6823                   null;
6824
6825                elsif Ekind (Ent) = E_Component
6826                  and then (No (Parent (Ent))
6827                              or else No (Expression (Parent (Ent))))
6828                  and then not Is_Fully_Initialized_Type (Etype (Ent))
6829
6830                   --  Special VM case for tag components, which need to be
6831                   --  defined in this case, but are never initialized as VMs
6832                   --  are using other dispatching mechanisms. Ignore this
6833                   --  uninitialized case. Note that this applies both to the
6834                   --  uTag entry and the main vtable pointer (CPP_Class case).
6835
6836                  and then (Tagged_Type_Expansion or else not Is_Tag (Ent))
6837                then
6838                   return False;
6839                end if;
6840
6841                Next_Entity (Ent);
6842             end loop;
6843          end;
6844
6845          --  No uninitialized components, so type is fully initialized.
6846          --  Note that this catches the case of no components as well.
6847
6848          return True;
6849
6850       elsif Is_Concurrent_Type (Typ) then
6851          return True;
6852
6853       elsif Is_Private_Type (Typ) then
6854          declare
6855             U : constant Entity_Id := Underlying_Type (Typ);
6856
6857          begin
6858             if No (U) then
6859                return False;
6860             else
6861                return Is_Fully_Initialized_Type (U);
6862             end if;
6863          end;
6864
6865       else
6866          return False;
6867       end if;
6868    end Is_Fully_Initialized_Type;
6869
6870    ----------------------------------
6871    -- Is_Fully_Initialized_Variant --
6872    ----------------------------------
6873
6874    function Is_Fully_Initialized_Variant (Typ : Entity_Id) return Boolean is
6875       Loc           : constant Source_Ptr := Sloc (Typ);
6876       Constraints   : constant List_Id    := New_List;
6877       Components    : constant Elist_Id   := New_Elmt_List;
6878       Comp_Elmt     : Elmt_Id;
6879       Comp_Id       : Node_Id;
6880       Comp_List     : Node_Id;
6881       Discr         : Entity_Id;
6882       Discr_Val     : Node_Id;
6883
6884       Report_Errors : Boolean;
6885       pragma Warnings (Off, Report_Errors);
6886
6887    begin
6888       if Serious_Errors_Detected > 0 then
6889          return False;
6890       end if;
6891
6892       if Is_Record_Type (Typ)
6893         and then Nkind (Parent (Typ)) = N_Full_Type_Declaration
6894         and then Nkind (Type_Definition (Parent (Typ))) = N_Record_Definition
6895       then
6896          Comp_List := Component_List (Type_Definition (Parent (Typ)));
6897
6898          Discr := First_Discriminant (Typ);
6899          while Present (Discr) loop
6900             if Nkind (Parent (Discr)) = N_Discriminant_Specification then
6901                Discr_Val := Expression (Parent (Discr));
6902
6903                if Present (Discr_Val)
6904                  and then Is_OK_Static_Expression (Discr_Val)
6905                then
6906                   Append_To (Constraints,
6907                     Make_Component_Association (Loc,
6908                       Choices    => New_List (New_Occurrence_Of (Discr, Loc)),
6909                       Expression => New_Copy (Discr_Val)));
6910                else
6911                   return False;
6912                end if;
6913             else
6914                return False;
6915             end if;
6916
6917             Next_Discriminant (Discr);
6918          end loop;
6919
6920          Gather_Components
6921            (Typ           => Typ,
6922             Comp_List     => Comp_List,
6923             Governed_By   => Constraints,
6924             Into          => Components,
6925             Report_Errors => Report_Errors);
6926
6927          --  Check that each component present is fully initialized
6928
6929          Comp_Elmt := First_Elmt (Components);
6930          while Present (Comp_Elmt) loop
6931             Comp_Id := Node (Comp_Elmt);
6932
6933             if Ekind (Comp_Id) = E_Component
6934               and then (No (Parent (Comp_Id))
6935                          or else No (Expression (Parent (Comp_Id))))
6936               and then not Is_Fully_Initialized_Type (Etype (Comp_Id))
6937             then
6938                return False;
6939             end if;
6940
6941             Next_Elmt (Comp_Elmt);
6942          end loop;
6943
6944          return True;
6945
6946       elsif Is_Private_Type (Typ) then
6947          declare
6948             U : constant Entity_Id := Underlying_Type (Typ);
6949
6950          begin
6951             if No (U) then
6952                return False;
6953             else
6954                return Is_Fully_Initialized_Variant (U);
6955             end if;
6956          end;
6957       else
6958          return False;
6959       end if;
6960    end Is_Fully_Initialized_Variant;
6961
6962    ------------
6963    -- Is_LHS --
6964    ------------
6965
6966    --  We seem to have a lot of overlapping functions that do similar things
6967    --  (testing for left hand sides or lvalues???). Anyway, since this one is
6968    --  purely syntactic, it should be in Sem_Aux I would think???
6969
6970    function Is_LHS (N : Node_Id) return Boolean is
6971       P : constant Node_Id := Parent (N);
6972
6973    begin
6974       if Nkind (P) = N_Assignment_Statement then
6975          return Name (P) = N;
6976
6977       elsif
6978         Nkind_In (P, N_Indexed_Component, N_Selected_Component, N_Slice)
6979       then
6980          return N = Prefix (P) and then Is_LHS (P);
6981
6982       else
6983          return False;
6984       end if;
6985    end Is_LHS;
6986
6987    ----------------------------
6988    -- Is_Inherited_Operation --
6989    ----------------------------
6990
6991    function Is_Inherited_Operation (E : Entity_Id) return Boolean is
6992       Kind : constant Node_Kind := Nkind (Parent (E));
6993    begin
6994       pragma Assert (Is_Overloadable (E));
6995       return Kind = N_Full_Type_Declaration
6996         or else Kind = N_Private_Extension_Declaration
6997         or else Kind = N_Subtype_Declaration
6998         or else (Ekind (E) = E_Enumeration_Literal
6999                   and then Is_Derived_Type (Etype (E)));
7000    end Is_Inherited_Operation;
7001
7002    -------------------------------------
7003    -- Is_Inherited_Operation_For_Type --
7004    -------------------------------------
7005
7006    function Is_Inherited_Operation_For_Type
7007      (E : Entity_Id; Typ : Entity_Id) return Boolean
7008    is
7009    begin
7010       return Is_Inherited_Operation (E)
7011         and then Etype (Parent (E)) = Typ;
7012    end Is_Inherited_Operation_For_Type;
7013
7014    -----------------------------
7015    -- Is_Library_Level_Entity --
7016    -----------------------------
7017
7018    function Is_Library_Level_Entity (E : Entity_Id) return Boolean is
7019    begin
7020       --  The following is a small optimization, and it also properly handles
7021       --  discriminals, which in task bodies might appear in expressions before
7022       --  the corresponding procedure has been created, and which therefore do
7023       --  not have an assigned scope.
7024
7025       if Is_Formal (E) then
7026          return False;
7027       end if;
7028
7029       --  Normal test is simply that the enclosing dynamic scope is Standard
7030
7031       return Enclosing_Dynamic_Scope (E) = Standard_Standard;
7032    end Is_Library_Level_Entity;
7033
7034    ---------------------------------
7035    -- Is_Local_Variable_Reference --
7036    ---------------------------------
7037
7038    function Is_Local_Variable_Reference (Expr : Node_Id) return Boolean is
7039    begin
7040       if not Is_Entity_Name (Expr) then
7041          return False;
7042
7043       else
7044          declare
7045             Ent : constant Entity_Id := Entity (Expr);
7046             Sub : constant Entity_Id := Enclosing_Subprogram (Ent);
7047          begin
7048             if not Ekind_In (Ent, E_Variable, E_In_Out_Parameter) then
7049                return False;
7050             else
7051                return Present (Sub) and then Sub = Current_Subprogram;
7052             end if;
7053          end;
7054       end if;
7055    end Is_Local_Variable_Reference;
7056
7057    -------------------------
7058    -- Is_Object_Reference --
7059    -------------------------
7060
7061    function Is_Object_Reference (N : Node_Id) return Boolean is
7062    begin
7063       if Is_Entity_Name (N) then
7064          return Present (Entity (N)) and then Is_Object (Entity (N));
7065
7066       else
7067          case Nkind (N) is
7068             when N_Indexed_Component | N_Slice =>
7069                return
7070                  Is_Object_Reference (Prefix (N))
7071                    or else Is_Access_Type (Etype (Prefix (N)));
7072
7073             --  In Ada95, a function call is a constant object; a procedure
7074             --  call is not.
7075
7076             when N_Function_Call =>
7077                return Etype (N) /= Standard_Void_Type;
7078
7079             --  A reference to the stream attribute Input is a function call
7080
7081             when N_Attribute_Reference =>
7082                return Attribute_Name (N) = Name_Input;
7083
7084             when N_Selected_Component =>
7085                return
7086                  Is_Object_Reference (Selector_Name (N))
7087                    and then
7088                      (Is_Object_Reference (Prefix (N))
7089                         or else Is_Access_Type (Etype (Prefix (N))));
7090
7091             when N_Explicit_Dereference =>
7092                return True;
7093
7094             --  A view conversion of a tagged object is an object reference
7095
7096             when N_Type_Conversion =>
7097                return Is_Tagged_Type (Etype (Subtype_Mark (N)))
7098                  and then Is_Tagged_Type (Etype (Expression (N)))
7099                  and then Is_Object_Reference (Expression (N));
7100
7101             --  An unchecked type conversion is considered to be an object if
7102             --  the operand is an object (this construction arises only as a
7103             --  result of expansion activities).
7104
7105             when N_Unchecked_Type_Conversion =>
7106                return True;
7107
7108             when others =>
7109                return False;
7110          end case;
7111       end if;
7112    end Is_Object_Reference;
7113
7114    -----------------------------------
7115    -- Is_OK_Variable_For_Out_Formal --
7116    -----------------------------------
7117
7118    function Is_OK_Variable_For_Out_Formal (AV : Node_Id) return Boolean is
7119    begin
7120       Note_Possible_Modification (AV, Sure => True);
7121
7122       --  We must reject parenthesized variable names. The check for
7123       --  Comes_From_Source is present because there are currently
7124       --  cases where the compiler violates this rule (e.g. passing
7125       --  a task object to its controlled Initialize routine).
7126
7127       if Paren_Count (AV) > 0 and then Comes_From_Source (AV) then
7128          return False;
7129
7130       --  A variable is always allowed
7131
7132       elsif Is_Variable (AV) then
7133          return True;
7134
7135       --  Unchecked conversions are allowed only if they come from the
7136       --  generated code, which sometimes uses unchecked conversions for out
7137       --  parameters in cases where code generation is unaffected. We tell
7138       --  source unchecked conversions by seeing if they are rewrites of an
7139       --  original Unchecked_Conversion function call, or of an explicit
7140       --  conversion of a function call.
7141
7142       elsif Nkind (AV) = N_Unchecked_Type_Conversion then
7143          if Nkind (Original_Node (AV)) = N_Function_Call then
7144             return False;
7145
7146          elsif Comes_From_Source (AV)
7147            and then Nkind (Original_Node (Expression (AV))) = N_Function_Call
7148          then
7149             return False;
7150
7151          elsif Nkind (Original_Node (AV)) = N_Type_Conversion then
7152             return Is_OK_Variable_For_Out_Formal (Expression (AV));
7153
7154          else
7155             return True;
7156          end if;
7157
7158       --  Normal type conversions are allowed if argument is a variable
7159
7160       elsif Nkind (AV) = N_Type_Conversion then
7161          if Is_Variable (Expression (AV))
7162            and then Paren_Count (Expression (AV)) = 0
7163          then
7164             Note_Possible_Modification (Expression (AV), Sure => True);
7165             return True;
7166
7167          --  We also allow a non-parenthesized expression that raises
7168          --  constraint error if it rewrites what used to be a variable
7169
7170          elsif Raises_Constraint_Error (Expression (AV))
7171             and then Paren_Count (Expression (AV)) = 0
7172             and then Is_Variable (Original_Node (Expression (AV)))
7173          then
7174             return True;
7175
7176          --  Type conversion of something other than a variable
7177
7178          else
7179             return False;
7180          end if;
7181
7182       --  If this node is rewritten, then test the original form, if that is
7183       --  OK, then we consider the rewritten node OK (for example, if the
7184       --  original node is a conversion, then Is_Variable will not be true
7185       --  but we still want to allow the conversion if it converts a variable).
7186
7187       elsif Original_Node (AV) /= AV then
7188          return Is_OK_Variable_For_Out_Formal (Original_Node (AV));
7189
7190       --  All other non-variables are rejected
7191
7192       else
7193          return False;
7194       end if;
7195    end Is_OK_Variable_For_Out_Formal;
7196
7197    -----------------------------------
7198    -- Is_Partially_Initialized_Type --
7199    -----------------------------------
7200
7201    function Is_Partially_Initialized_Type
7202      (Typ              : Entity_Id;
7203       Include_Implicit : Boolean := True) return Boolean
7204    is
7205    begin
7206       if Is_Scalar_Type (Typ) then
7207          return False;
7208
7209       elsif Is_Access_Type (Typ) then
7210          return Include_Implicit;
7211
7212       elsif Is_Array_Type (Typ) then
7213
7214          --  If component type is partially initialized, so is array type
7215
7216          if Is_Partially_Initialized_Type
7217               (Component_Type (Typ), Include_Implicit)
7218          then
7219             return True;
7220
7221          --  Otherwise we are only partially initialized if we are fully
7222          --  initialized (this is the empty array case, no point in us
7223          --  duplicating that code here).
7224
7225          else
7226             return Is_Fully_Initialized_Type (Typ);
7227          end if;
7228
7229       elsif Is_Record_Type (Typ) then
7230
7231          --  A discriminated type is always partially initialized if in
7232          --  all mode
7233
7234          if Has_Discriminants (Typ) and then Include_Implicit then
7235             return True;
7236
7237          --  A tagged type is always partially initialized
7238
7239          elsif Is_Tagged_Type (Typ) then
7240             return True;
7241
7242          --  Case of non-discriminated record
7243
7244          else
7245             declare
7246                Ent : Entity_Id;
7247
7248                Component_Present : Boolean := False;
7249                --  Set True if at least one component is present. If no
7250                --  components are present, then record type is fully
7251                --  initialized (another odd case, like the null array).
7252
7253             begin
7254                --  Loop through components
7255
7256                Ent := First_Entity (Typ);
7257                while Present (Ent) loop
7258                   if Ekind (Ent) = E_Component then
7259                      Component_Present := True;
7260
7261                      --  If a component has an initialization expression then
7262                      --  the enclosing record type is partially initialized
7263
7264                      if Present (Parent (Ent))
7265                        and then Present (Expression (Parent (Ent)))
7266                      then
7267                         return True;
7268
7269                      --  If a component is of a type which is itself partially
7270                      --  initialized, then the enclosing record type is also.
7271
7272                      elsif Is_Partially_Initialized_Type
7273                              (Etype (Ent), Include_Implicit)
7274                      then
7275                         return True;
7276                      end if;
7277                   end if;
7278
7279                   Next_Entity (Ent);
7280                end loop;
7281
7282                --  No initialized components found. If we found any components
7283                --  they were all uninitialized so the result is false.
7284
7285                if Component_Present then
7286                   return False;
7287
7288                --  But if we found no components, then all the components are
7289                --  initialized so we consider the type to be initialized.
7290
7291                else
7292                   return True;
7293                end if;
7294             end;
7295          end if;
7296
7297       --  Concurrent types are always fully initialized
7298
7299       elsif Is_Concurrent_Type (Typ) then
7300          return True;
7301
7302       --  For a private type, go to underlying type. If there is no underlying
7303       --  type then just assume this partially initialized. Not clear if this
7304       --  can happen in a non-error case, but no harm in testing for this.
7305
7306       elsif Is_Private_Type (Typ) then
7307          declare
7308             U : constant Entity_Id := Underlying_Type (Typ);
7309          begin
7310             if No (U) then
7311                return True;
7312             else
7313                return Is_Partially_Initialized_Type (U, Include_Implicit);
7314             end if;
7315          end;
7316
7317       --  For any other type (are there any?) assume partially initialized
7318
7319       else
7320          return True;
7321       end if;
7322    end Is_Partially_Initialized_Type;
7323
7324    ------------------------------------
7325    -- Is_Potentially_Persistent_Type --
7326    ------------------------------------
7327
7328    function Is_Potentially_Persistent_Type (T : Entity_Id) return Boolean is
7329       Comp : Entity_Id;
7330       Indx : Node_Id;
7331
7332    begin
7333       --  For private type, test corresponding full type
7334
7335       if Is_Private_Type (T) then
7336          return Is_Potentially_Persistent_Type (Full_View (T));
7337
7338       --  Scalar types are potentially persistent
7339
7340       elsif Is_Scalar_Type (T) then
7341          return True;
7342
7343       --  Record type is potentially persistent if not tagged and the types of
7344       --  all it components are potentially persistent, and no component has
7345       --  an initialization expression.
7346
7347       elsif Is_Record_Type (T)
7348         and then not Is_Tagged_Type (T)
7349         and then not Is_Partially_Initialized_Type (T)
7350       then
7351          Comp := First_Component (T);
7352          while Present (Comp) loop
7353             if not Is_Potentially_Persistent_Type (Etype (Comp)) then
7354                return False;
7355             else
7356                Next_Entity (Comp);
7357             end if;
7358          end loop;
7359
7360          return True;
7361
7362       --  Array type is potentially persistent if its component type is
7363       --  potentially persistent and if all its constraints are static.
7364
7365       elsif Is_Array_Type (T) then
7366          if not Is_Potentially_Persistent_Type (Component_Type (T)) then
7367             return False;
7368          end if;
7369
7370          Indx := First_Index (T);
7371          while Present (Indx) loop
7372             if not Is_OK_Static_Subtype (Etype (Indx)) then
7373                return False;
7374             else
7375                Next_Index (Indx);
7376             end if;
7377          end loop;
7378
7379          return True;
7380
7381       --  All other types are not potentially persistent
7382
7383       else
7384          return False;
7385       end if;
7386    end Is_Potentially_Persistent_Type;
7387
7388    ---------------------------------
7389    -- Is_Protected_Self_Reference --
7390    ---------------------------------
7391
7392    function Is_Protected_Self_Reference (N : Node_Id) return Boolean is
7393
7394       function In_Access_Definition (N : Node_Id) return Boolean;
7395       --  Returns true if N belongs to an access definition
7396
7397       --------------------------
7398       -- In_Access_Definition --
7399       --------------------------
7400
7401       function In_Access_Definition (N : Node_Id) return Boolean is
7402          P : Node_Id;
7403
7404       begin
7405          P := Parent (N);
7406          while Present (P) loop
7407             if Nkind (P) = N_Access_Definition then
7408                return True;
7409             end if;
7410
7411             P := Parent (P);
7412          end loop;
7413
7414          return False;
7415       end In_Access_Definition;
7416
7417    --  Start of processing for Is_Protected_Self_Reference
7418
7419    begin
7420       --  Verify that prefix is analyzed and has the proper form. Note that
7421       --  the attributes Elab_Spec, Elab_Body, and UET_Address, which also
7422       --  produce the address of an entity, do not analyze their prefix
7423       --  because they denote entities that are not necessarily visible.
7424       --  Neither of them can apply to a protected type.
7425
7426       return Ada_Version >= Ada_2005
7427         and then Is_Entity_Name (N)
7428         and then Present (Entity (N))
7429         and then Is_Protected_Type (Entity (N))
7430         and then In_Open_Scopes (Entity (N))
7431         and then not In_Access_Definition (N);
7432    end Is_Protected_Self_Reference;
7433
7434    -----------------------------
7435    -- Is_RCI_Pkg_Spec_Or_Body --
7436    -----------------------------
7437
7438    function Is_RCI_Pkg_Spec_Or_Body (Cunit : Node_Id) return Boolean is
7439
7440       function Is_RCI_Pkg_Decl_Cunit (Cunit : Node_Id) return Boolean;
7441       --  Return True if the unit of Cunit is an RCI package declaration
7442
7443       ---------------------------
7444       -- Is_RCI_Pkg_Decl_Cunit --
7445       ---------------------------
7446
7447       function Is_RCI_Pkg_Decl_Cunit (Cunit : Node_Id) return Boolean is
7448          The_Unit : constant Node_Id := Unit (Cunit);
7449
7450       begin
7451          if Nkind (The_Unit) /= N_Package_Declaration then
7452             return False;
7453          end if;
7454
7455          return Is_Remote_Call_Interface (Defining_Entity (The_Unit));
7456       end Is_RCI_Pkg_Decl_Cunit;
7457
7458    --  Start of processing for Is_RCI_Pkg_Spec_Or_Body
7459
7460    begin
7461       return Is_RCI_Pkg_Decl_Cunit (Cunit)
7462         or else
7463          (Nkind (Unit (Cunit)) = N_Package_Body
7464            and then Is_RCI_Pkg_Decl_Cunit (Library_Unit (Cunit)));
7465    end Is_RCI_Pkg_Spec_Or_Body;
7466
7467    -----------------------------------------
7468    -- Is_Remote_Access_To_Class_Wide_Type --
7469    -----------------------------------------
7470
7471    function Is_Remote_Access_To_Class_Wide_Type
7472      (E : Entity_Id) return Boolean
7473    is
7474    begin
7475       --  A remote access to class-wide type is a general access to object type
7476       --  declared in the visible part of a Remote_Types or Remote_Call_
7477       --  Interface unit.
7478
7479       return Ekind (E) = E_General_Access_Type
7480         and then (Is_Remote_Call_Interface (E) or else Is_Remote_Types (E));
7481    end Is_Remote_Access_To_Class_Wide_Type;
7482
7483    -----------------------------------------
7484    -- Is_Remote_Access_To_Subprogram_Type --
7485    -----------------------------------------
7486
7487    function Is_Remote_Access_To_Subprogram_Type
7488      (E : Entity_Id) return Boolean
7489    is
7490    begin
7491       return (Ekind (E) = E_Access_Subprogram_Type
7492                 or else (Ekind (E) = E_Record_Type
7493                            and then Present (Corresponding_Remote_Type (E))))
7494         and then (Is_Remote_Call_Interface (E) or else Is_Remote_Types (E));
7495    end Is_Remote_Access_To_Subprogram_Type;
7496
7497    --------------------
7498    -- Is_Remote_Call --
7499    --------------------
7500
7501    function Is_Remote_Call (N : Node_Id) return Boolean is
7502    begin
7503       if Nkind (N) /= N_Procedure_Call_Statement
7504         and then Nkind (N) /= N_Function_Call
7505       then
7506          --  An entry call cannot be remote
7507
7508          return False;
7509
7510       elsif Nkind (Name (N)) in N_Has_Entity
7511         and then Is_Remote_Call_Interface (Entity (Name (N)))
7512       then
7513          --  A subprogram declared in the spec of a RCI package is remote
7514
7515          return True;
7516
7517       elsif Nkind (Name (N)) = N_Explicit_Dereference
7518         and then Is_Remote_Access_To_Subprogram_Type
7519                    (Etype (Prefix (Name (N))))
7520       then
7521          --  The dereference of a RAS is a remote call
7522
7523          return True;
7524
7525       elsif Present (Controlling_Argument (N))
7526         and then Is_Remote_Access_To_Class_Wide_Type
7527           (Etype (Controlling_Argument (N)))
7528       then
7529          --  Any primitive operation call with a controlling argument of
7530          --  a RACW type is a remote call.
7531
7532          return True;
7533       end if;
7534
7535       --  All other calls are local calls
7536
7537       return False;
7538    end Is_Remote_Call;
7539
7540    ----------------------
7541    -- Is_Renamed_Entry --
7542    ----------------------
7543
7544    function Is_Renamed_Entry (Proc_Nam : Entity_Id) return Boolean is
7545       Orig_Node : Node_Id := Empty;
7546       Subp_Decl : Node_Id := Parent (Parent (Proc_Nam));
7547
7548       function Is_Entry (Nam : Node_Id) return Boolean;
7549       --  Determine whether Nam is an entry. Traverse selectors if there are
7550       --  nested selected components.
7551
7552       --------------
7553       -- Is_Entry --
7554       --------------
7555
7556       function Is_Entry (Nam : Node_Id) return Boolean is
7557       begin
7558          if Nkind (Nam) = N_Selected_Component then
7559             return Is_Entry (Selector_Name (Nam));
7560          end if;
7561
7562          return Ekind (Entity (Nam)) = E_Entry;
7563       end Is_Entry;
7564
7565    --  Start of processing for Is_Renamed_Entry
7566
7567    begin
7568       if Present (Alias (Proc_Nam)) then
7569          Subp_Decl := Parent (Parent (Alias (Proc_Nam)));
7570       end if;
7571
7572       --  Look for a rewritten subprogram renaming declaration
7573
7574       if Nkind (Subp_Decl) = N_Subprogram_Declaration
7575         and then Present (Original_Node (Subp_Decl))
7576       then
7577          Orig_Node := Original_Node (Subp_Decl);
7578       end if;
7579
7580       --  The rewritten subprogram is actually an entry
7581
7582       if Present (Orig_Node)
7583         and then Nkind (Orig_Node) = N_Subprogram_Renaming_Declaration
7584         and then Is_Entry (Name (Orig_Node))
7585       then
7586          return True;
7587       end if;
7588
7589       return False;
7590    end Is_Renamed_Entry;
7591
7592    ----------------------
7593    -- Is_Selector_Name --
7594    ----------------------
7595
7596    function Is_Selector_Name (N : Node_Id) return Boolean is
7597    begin
7598       if not Is_List_Member (N) then
7599          declare
7600             P : constant Node_Id   := Parent (N);
7601             K : constant Node_Kind := Nkind (P);
7602          begin
7603             return
7604               (K = N_Expanded_Name          or else
7605                K = N_Generic_Association    or else
7606                K = N_Parameter_Association  or else
7607                K = N_Selected_Component)
7608               and then Selector_Name (P) = N;
7609          end;
7610
7611       else
7612          declare
7613             L : constant List_Id := List_Containing (N);
7614             P : constant Node_Id := Parent (L);
7615          begin
7616             return (Nkind (P) = N_Discriminant_Association
7617                      and then Selector_Names (P) = L)
7618               or else
7619                    (Nkind (P) = N_Component_Association
7620                      and then Choices (P) = L);
7621          end;
7622       end if;
7623    end Is_Selector_Name;
7624
7625    ----------------------------------
7626    -- Is_SPARK_Initialization_Expr --
7627    ----------------------------------
7628
7629    function Is_SPARK_Initialization_Expr (N : Node_Id) return Boolean is
7630       Is_Ok     : Boolean;
7631       Expr      : Node_Id;
7632       Comp_Assn : Node_Id;
7633       Orig_N    : constant Node_Id := Original_Node (N);
7634
7635    begin
7636       Is_Ok := True;
7637
7638       if not Comes_From_Source (Orig_N) then
7639          goto Done;
7640       end if;
7641
7642       pragma Assert (Nkind (Orig_N) in N_Subexpr);
7643
7644       case Nkind (Orig_N) is
7645          when N_Character_Literal |
7646               N_Integer_Literal   |
7647               N_Real_Literal      |
7648               N_String_Literal    =>
7649             null;
7650
7651          when N_Identifier    |
7652               N_Expanded_Name =>
7653             if Is_Entity_Name (Orig_N)
7654               and then Present (Entity (Orig_N))  --  needed in some cases
7655             then
7656                case Ekind (Entity (Orig_N)) is
7657                   when E_Constant            |
7658                        E_Enumeration_Literal |
7659                        E_Named_Integer       |
7660                        E_Named_Real          =>
7661                      null;
7662                   when others =>
7663                      if Is_Type (Entity (Orig_N)) then
7664                         null;
7665                      else
7666                         Is_Ok := False;
7667                      end if;
7668                end case;
7669             end if;
7670
7671          when N_Qualified_Expression |
7672               N_Type_Conversion      =>
7673             Is_Ok := Is_SPARK_Initialization_Expr (Expression (Orig_N));
7674
7675          when N_Unary_Op =>
7676             Is_Ok := Is_SPARK_Initialization_Expr (Right_Opnd (Orig_N));
7677
7678          when N_Binary_Op       |
7679               N_Short_Circuit   |
7680               N_Membership_Test =>
7681             Is_Ok := Is_SPARK_Initialization_Expr (Left_Opnd (Orig_N))
7682               and then Is_SPARK_Initialization_Expr (Right_Opnd (Orig_N));
7683
7684          when N_Aggregate           |
7685               N_Extension_Aggregate =>
7686             if Nkind (Orig_N) = N_Extension_Aggregate then
7687                Is_Ok := Is_SPARK_Initialization_Expr (Ancestor_Part (Orig_N));
7688             end if;
7689
7690             Expr := First (Expressions (Orig_N));
7691             while Present (Expr) loop
7692                if not Is_SPARK_Initialization_Expr (Expr) then
7693                   Is_Ok := False;
7694                   goto Done;
7695                end if;
7696
7697                Next (Expr);
7698             end loop;
7699
7700             Comp_Assn := First (Component_Associations (Orig_N));
7701             while Present (Comp_Assn) loop
7702                Expr := Expression (Comp_Assn);
7703                if Present (Expr)  --  needed for box association
7704                  and then not Is_SPARK_Initialization_Expr (Expr)
7705                then
7706                   Is_Ok := False;
7707                   goto Done;
7708                end if;
7709
7710                Next (Comp_Assn);
7711             end loop;
7712
7713          when N_Attribute_Reference =>
7714             if Nkind (Prefix (Orig_N)) in N_Subexpr then
7715                Is_Ok := Is_SPARK_Initialization_Expr (Prefix (Orig_N));
7716             end if;
7717
7718             Expr := First (Expressions (Orig_N));
7719             while Present (Expr) loop
7720                if not Is_SPARK_Initialization_Expr (Expr) then
7721                   Is_Ok := False;
7722                   goto Done;
7723                end if;
7724
7725                Next (Expr);
7726             end loop;
7727
7728          --  Selected components might be expanded named not yet resolved, so
7729          --  default on the safe side. (Eg on sparklex.ads)
7730
7731          when N_Selected_Component =>
7732             null;
7733
7734          when others =>
7735             Is_Ok := False;
7736       end case;
7737
7738    <<Done>>
7739       return Is_Ok;
7740    end Is_SPARK_Initialization_Expr;
7741
7742    -------------------------------
7743    -- Is_SPARK_Object_Reference --
7744    -------------------------------
7745
7746    function Is_SPARK_Object_Reference (N : Node_Id) return Boolean is
7747    begin
7748       if Is_Entity_Name (N) then
7749          return Present (Entity (N))
7750            and then
7751              (Ekind_In (Entity (N), E_Constant, E_Variable)
7752               or else Ekind (Entity (N)) in Formal_Kind);
7753
7754       else
7755          case Nkind (N) is
7756             when N_Selected_Component =>
7757                return Is_SPARK_Object_Reference (Prefix (N));
7758
7759             when others =>
7760                return False;
7761          end case;
7762       end if;
7763    end Is_SPARK_Object_Reference;
7764
7765    ------------------
7766    -- Is_Statement --
7767    ------------------
7768
7769    function Is_Statement (N : Node_Id) return Boolean is
7770    begin
7771       return
7772         Nkind (N) in N_Statement_Other_Than_Procedure_Call
7773           or else Nkind (N) = N_Procedure_Call_Statement;
7774    end Is_Statement;
7775
7776    ---------------------------------
7777    -- Is_Synchronized_Tagged_Type --
7778    ---------------------------------
7779
7780    function Is_Synchronized_Tagged_Type (E : Entity_Id) return Boolean is
7781       Kind : constant Entity_Kind := Ekind (Base_Type (E));
7782
7783    begin
7784       --  A task or protected type derived from an interface is a tagged type.
7785       --  Such a tagged type is called a synchronized tagged type, as are
7786       --  synchronized interfaces and private extensions whose declaration
7787       --  includes the reserved word synchronized.
7788
7789       return (Is_Tagged_Type (E)
7790                 and then (Kind = E_Task_Type
7791                            or else Kind = E_Protected_Type))
7792             or else
7793              (Is_Interface (E)
7794                 and then Is_Synchronized_Interface (E))
7795             or else
7796              (Ekind (E) = E_Record_Type_With_Private
7797                 and then Nkind (Parent (E)) = N_Private_Extension_Declaration
7798                 and then (Synchronized_Present (Parent (E))
7799                            or else Is_Synchronized_Interface (Etype (E))));
7800    end Is_Synchronized_Tagged_Type;
7801
7802    -----------------
7803    -- Is_Transfer --
7804    -----------------
7805
7806    function Is_Transfer (N : Node_Id) return Boolean is
7807       Kind : constant Node_Kind := Nkind (N);
7808
7809    begin
7810       if Kind = N_Simple_Return_Statement
7811            or else
7812          Kind = N_Extended_Return_Statement
7813            or else
7814          Kind = N_Goto_Statement
7815            or else
7816          Kind = N_Raise_Statement
7817            or else
7818          Kind = N_Requeue_Statement
7819       then
7820          return True;
7821
7822       elsif (Kind = N_Exit_Statement or else Kind in N_Raise_xxx_Error)
7823         and then No (Condition (N))
7824       then
7825          return True;
7826
7827       elsif Kind = N_Procedure_Call_Statement
7828         and then Is_Entity_Name (Name (N))
7829         and then Present (Entity (Name (N)))
7830         and then No_Return (Entity (Name (N)))
7831       then
7832          return True;
7833
7834       elsif Nkind (Original_Node (N)) = N_Raise_Statement then
7835          return True;
7836
7837       else
7838          return False;
7839       end if;
7840    end Is_Transfer;
7841
7842    -------------
7843    -- Is_True --
7844    -------------
7845
7846    function Is_True (U : Uint) return Boolean is
7847    begin
7848       return (U /= 0);
7849    end Is_True;
7850
7851    -------------------------------
7852    -- Is_Universal_Numeric_Type --
7853    -------------------------------
7854
7855    function Is_Universal_Numeric_Type (T : Entity_Id) return Boolean is
7856    begin
7857       return T = Universal_Integer or else T = Universal_Real;
7858    end Is_Universal_Numeric_Type;
7859
7860    -------------------
7861    -- Is_Value_Type --
7862    -------------------
7863
7864    function Is_Value_Type (T : Entity_Id) return Boolean is
7865    begin
7866       return VM_Target = CLI_Target
7867         and then Nkind (T) in N_Has_Chars
7868         and then Chars (T) /= No_Name
7869         and then Get_Name_String (Chars (T)) = "valuetype";
7870    end Is_Value_Type;
7871
7872    ---------------------
7873    -- Is_VMS_Operator --
7874    ---------------------
7875
7876    function Is_VMS_Operator (Op : Entity_Id) return Boolean is
7877    begin
7878       --  The VMS operators are declared in a child of System that is loaded
7879       --  through pragma Extend_System. In some rare cases a program is run
7880       --  with this extension but without indicating that the target is VMS.
7881
7882       return Ekind (Op) = E_Function
7883         and then Is_Intrinsic_Subprogram (Op)
7884         and then
7885           ((Present_System_Aux
7886             and then Scope (Op) = System_Aux_Id)
7887            or else
7888            (True_VMS_Target
7889              and then Scope (Scope (Op)) = RTU_Entity (System)));
7890    end Is_VMS_Operator;
7891
7892    -----------------
7893    -- Is_Variable --
7894    -----------------
7895
7896    function Is_Variable
7897      (N                 : Node_Id;
7898       Use_Original_Node : Boolean := True) return Boolean
7899    is
7900       Orig_Node : Node_Id;
7901
7902       function In_Protected_Function (E : Entity_Id) return Boolean;
7903       --  Within a protected function, the private components of the enclosing
7904       --  protected type are constants. A function nested within a (protected)
7905       --  procedure is not itself protected.
7906
7907       function Is_Variable_Prefix (P : Node_Id) return Boolean;
7908       --  Prefixes can involve implicit dereferences, in which case we must
7909       --  test for the case of a reference of a constant access type, which can
7910       --  can never be a variable.
7911
7912       ---------------------------
7913       -- In_Protected_Function --
7914       ---------------------------
7915
7916       function In_Protected_Function (E : Entity_Id) return Boolean is
7917          Prot : constant Entity_Id := Scope (E);
7918          S    : Entity_Id;
7919
7920       begin
7921          if not Is_Protected_Type (Prot) then
7922             return False;
7923          else
7924             S := Current_Scope;
7925             while Present (S) and then S /= Prot loop
7926                if Ekind (S) = E_Function and then Scope (S) = Prot then
7927                   return True;
7928                end if;
7929
7930                S := Scope (S);
7931             end loop;
7932
7933             return False;
7934          end if;
7935       end In_Protected_Function;
7936
7937       ------------------------
7938       -- Is_Variable_Prefix --
7939       ------------------------
7940
7941       function Is_Variable_Prefix (P : Node_Id) return Boolean is
7942       begin
7943          if Is_Access_Type (Etype (P)) then
7944             return not Is_Access_Constant (Root_Type (Etype (P)));
7945
7946          --  For the case of an indexed component whose prefix has a packed
7947          --  array type, the prefix has been rewritten into a type conversion.
7948          --  Determine variable-ness from the converted expression.
7949
7950          elsif Nkind (P) = N_Type_Conversion
7951            and then not Comes_From_Source (P)
7952            and then Is_Array_Type (Etype (P))
7953            and then Is_Packed (Etype (P))
7954          then
7955             return Is_Variable (Expression (P));
7956
7957          else
7958             return Is_Variable (P);
7959          end if;
7960       end Is_Variable_Prefix;
7961
7962    --  Start of processing for Is_Variable
7963
7964    begin
7965       --  Check if we perform the test on the original node since this may be a
7966       --  test of syntactic categories which must not be disturbed by whatever
7967       --  rewriting might have occurred. For example, an aggregate, which is
7968       --  certainly NOT a variable, could be turned into a variable by
7969       --  expansion.
7970
7971       if Use_Original_Node then
7972          Orig_Node := Original_Node (N);
7973       else
7974          Orig_Node := N;
7975       end if;
7976
7977       --  Definitely OK if Assignment_OK is set. Since this is something that
7978       --  only gets set for expanded nodes, the test is on N, not Orig_Node.
7979
7980       if Nkind (N) in N_Subexpr and then Assignment_OK (N) then
7981          return True;
7982
7983       --  Normally we go to the original node, but there is one exception where
7984       --  we use the rewritten node, namely when it is an explicit dereference.
7985       --  The generated code may rewrite a prefix which is an access type with
7986       --  an explicit dereference. The dereference is a variable, even though
7987       --  the original node may not be (since it could be a constant of the
7988       --  access type).
7989
7990       --  In Ada 2005 we have a further case to consider: the prefix may be a
7991       --  function call given in prefix notation. The original node appears to
7992       --  be a selected component, but we need to examine the call.
7993
7994       elsif Nkind (N) = N_Explicit_Dereference
7995         and then Nkind (Orig_Node) /= N_Explicit_Dereference
7996         and then Present (Etype (Orig_Node))
7997         and then Is_Access_Type (Etype (Orig_Node))
7998       then
7999          --  Note that if the prefix is an explicit dereference that does not
8000          --  come from source, we must check for a rewritten function call in
8001          --  prefixed notation before other forms of rewriting, to prevent a
8002          --  compiler crash.
8003
8004          return
8005            (Nkind (Orig_Node) = N_Function_Call
8006              and then not Is_Access_Constant (Etype (Prefix (N))))
8007            or else
8008              Is_Variable_Prefix (Original_Node (Prefix (N)));
8009
8010       --  A function call is never a variable
8011
8012       elsif Nkind (N) = N_Function_Call then
8013          return False;
8014
8015       --  All remaining checks use the original node
8016
8017       elsif Is_Entity_Name (Orig_Node)
8018         and then Present (Entity (Orig_Node))
8019       then
8020          declare
8021             E : constant Entity_Id := Entity (Orig_Node);
8022             K : constant Entity_Kind := Ekind (E);
8023
8024          begin
8025             return (K = E_Variable
8026                       and then Nkind (Parent (E)) /= N_Exception_Handler)
8027               or else  (K = E_Component
8028                           and then not In_Protected_Function (E))
8029               or else  K = E_Out_Parameter
8030               or else  K = E_In_Out_Parameter
8031               or else  K = E_Generic_In_Out_Parameter
8032
8033                --  Current instance of type:
8034
8035               or else (Is_Type (E) and then In_Open_Scopes (E))
8036               or else (Is_Incomplete_Or_Private_Type (E)
8037                         and then In_Open_Scopes (Full_View (E)));
8038          end;
8039
8040       else
8041          case Nkind (Orig_Node) is
8042             when N_Indexed_Component | N_Slice =>
8043                return Is_Variable_Prefix (Prefix (Orig_Node));
8044
8045             when N_Selected_Component =>
8046                return Is_Variable_Prefix (Prefix (Orig_Node))
8047                  and then Is_Variable (Selector_Name (Orig_Node));
8048
8049             --  For an explicit dereference, the type of the prefix cannot
8050             --  be an access to constant or an access to subprogram.
8051
8052             when N_Explicit_Dereference =>
8053                declare
8054                   Typ : constant Entity_Id := Etype (Prefix (Orig_Node));
8055                begin
8056                   return Is_Access_Type (Typ)
8057                     and then not Is_Access_Constant (Root_Type (Typ))
8058                     and then Ekind (Typ) /= E_Access_Subprogram_Type;
8059                end;
8060
8061             --  The type conversion is the case where we do not deal with the
8062             --  context dependent special case of an actual parameter. Thus
8063             --  the type conversion is only considered a variable for the
8064             --  purposes of this routine if the target type is tagged. However,
8065             --  a type conversion is considered to be a variable if it does not
8066             --  come from source (this deals for example with the conversions
8067             --  of expressions to their actual subtypes).
8068
8069             when N_Type_Conversion =>
8070                return Is_Variable (Expression (Orig_Node))
8071                  and then
8072                    (not Comes_From_Source (Orig_Node)
8073                       or else
8074                         (Is_Tagged_Type (Etype (Subtype_Mark (Orig_Node)))
8075                           and then
8076                          Is_Tagged_Type (Etype (Expression (Orig_Node)))));
8077
8078             --  GNAT allows an unchecked type conversion as a variable. This
8079             --  only affects the generation of internal expanded code, since
8080             --  calls to instantiations of Unchecked_Conversion are never
8081             --  considered variables (since they are function calls).
8082             --  This is also true for expression actions.
8083
8084             when N_Unchecked_Type_Conversion =>
8085                return Is_Variable (Expression (Orig_Node));
8086
8087             when others =>
8088                return False;
8089          end case;
8090       end if;
8091    end Is_Variable;
8092
8093    ---------------------------
8094    -- Is_Visibly_Controlled --
8095    ---------------------------
8096
8097    function Is_Visibly_Controlled (T : Entity_Id) return Boolean is
8098       Root : constant Entity_Id := Root_Type (T);
8099    begin
8100       return Chars (Scope (Root)) = Name_Finalization
8101         and then Chars (Scope (Scope (Root))) = Name_Ada
8102         and then Scope (Scope (Scope (Root))) = Standard_Standard;
8103    end Is_Visibly_Controlled;
8104
8105    ------------------------
8106    -- Is_Volatile_Object --
8107    ------------------------
8108
8109    function Is_Volatile_Object (N : Node_Id) return Boolean is
8110
8111       function Object_Has_Volatile_Components (N : Node_Id) return Boolean;
8112       --  Determines if given object has volatile components
8113
8114       function Is_Volatile_Prefix (N : Node_Id) return Boolean;
8115       --  If prefix is an implicit dereference, examine designated type
8116
8117       ------------------------
8118       -- Is_Volatile_Prefix --
8119       ------------------------
8120
8121       function Is_Volatile_Prefix (N : Node_Id) return Boolean is
8122          Typ  : constant Entity_Id := Etype (N);
8123
8124       begin
8125          if Is_Access_Type (Typ) then
8126             declare
8127                Dtyp : constant Entity_Id := Designated_Type (Typ);
8128
8129             begin
8130                return Is_Volatile (Dtyp)
8131                  or else Has_Volatile_Components (Dtyp);
8132             end;
8133
8134          else
8135             return Object_Has_Volatile_Components (N);
8136          end if;
8137       end Is_Volatile_Prefix;
8138
8139       ------------------------------------
8140       -- Object_Has_Volatile_Components --
8141       ------------------------------------
8142
8143       function Object_Has_Volatile_Components (N : Node_Id) return Boolean is
8144          Typ : constant Entity_Id := Etype (N);
8145
8146       begin
8147          if Is_Volatile (Typ)
8148            or else Has_Volatile_Components (Typ)
8149          then
8150             return True;
8151
8152          elsif Is_Entity_Name (N)
8153            and then (Has_Volatile_Components (Entity (N))
8154                       or else Is_Volatile (Entity (N)))
8155          then
8156             return True;
8157
8158          elsif Nkind (N) = N_Indexed_Component
8159            or else Nkind (N) = N_Selected_Component
8160          then
8161             return Is_Volatile_Prefix (Prefix (N));
8162
8163          else
8164             return False;
8165          end if;
8166       end Object_Has_Volatile_Components;
8167
8168    --  Start of processing for Is_Volatile_Object
8169
8170    begin
8171       if Is_Volatile (Etype (N))
8172         or else (Is_Entity_Name (N) and then Is_Volatile (Entity (N)))
8173       then
8174          return True;
8175
8176       elsif Nkind (N) = N_Indexed_Component
8177         or else Nkind (N) = N_Selected_Component
8178       then
8179          return Is_Volatile_Prefix (Prefix (N));
8180
8181       else
8182          return False;
8183       end if;
8184    end Is_Volatile_Object;
8185
8186    -------------------------
8187    -- Kill_Current_Values --
8188    -------------------------
8189
8190    procedure Kill_Current_Values
8191      (Ent                  : Entity_Id;
8192       Last_Assignment_Only : Boolean := False)
8193    is
8194    begin
8195       --  ??? do we have to worry about clearing cached checks?
8196
8197       if Is_Assignable (Ent) then
8198          Set_Last_Assignment (Ent, Empty);
8199       end if;
8200
8201       if Is_Object (Ent) then
8202          if not Last_Assignment_Only then
8203             Kill_Checks (Ent);
8204             Set_Current_Value (Ent, Empty);
8205
8206             if not Can_Never_Be_Null (Ent) then
8207                Set_Is_Known_Non_Null (Ent, False);
8208             end if;
8209
8210             Set_Is_Known_Null (Ent, False);
8211
8212             --  Reset Is_Known_Valid unless type is always valid, or if we have
8213             --  a loop parameter (loop parameters are always valid, since their
8214             --  bounds are defined by the bounds given in the loop header).
8215
8216             if not Is_Known_Valid (Etype (Ent))
8217               and then Ekind (Ent) /= E_Loop_Parameter
8218             then
8219                Set_Is_Known_Valid (Ent, False);
8220             end if;
8221          end if;
8222       end if;
8223    end Kill_Current_Values;
8224
8225    procedure Kill_Current_Values (Last_Assignment_Only : Boolean := False) is
8226       S : Entity_Id;
8227
8228       procedure Kill_Current_Values_For_Entity_Chain (E : Entity_Id);
8229       --  Clear current value for entity E and all entities chained to E
8230
8231       ------------------------------------------
8232       -- Kill_Current_Values_For_Entity_Chain --
8233       ------------------------------------------
8234
8235       procedure Kill_Current_Values_For_Entity_Chain (E : Entity_Id) is
8236          Ent : Entity_Id;
8237       begin
8238          Ent := E;
8239          while Present (Ent) loop
8240             Kill_Current_Values (Ent, Last_Assignment_Only);
8241             Next_Entity (Ent);
8242          end loop;
8243       end Kill_Current_Values_For_Entity_Chain;
8244
8245    --  Start of processing for Kill_Current_Values
8246
8247    begin
8248       --  Kill all saved checks, a special case of killing saved values
8249
8250       if not Last_Assignment_Only then
8251          Kill_All_Checks;
8252       end if;
8253
8254       --  Loop through relevant scopes, which includes the current scope and
8255       --  any parent scopes if the current scope is a block or a package.
8256
8257       S := Current_Scope;
8258       Scope_Loop : loop
8259
8260          --  Clear current values of all entities in current scope
8261
8262          Kill_Current_Values_For_Entity_Chain (First_Entity (S));
8263
8264          --  If scope is a package, also clear current values of all
8265          --  private entities in the scope.
8266
8267          if Is_Package_Or_Generic_Package (S)
8268            or else Is_Concurrent_Type (S)
8269          then
8270             Kill_Current_Values_For_Entity_Chain (First_Private_Entity (S));
8271          end if;
8272
8273          --  If this is a not a subprogram, deal with parents
8274
8275          if not Is_Subprogram (S) then
8276             S := Scope (S);
8277             exit Scope_Loop when S = Standard_Standard;
8278          else
8279             exit Scope_Loop;
8280          end if;
8281       end loop Scope_Loop;
8282    end Kill_Current_Values;
8283
8284    --------------------------
8285    -- Kill_Size_Check_Code --
8286    --------------------------
8287
8288    procedure Kill_Size_Check_Code (E : Entity_Id) is
8289    begin
8290       if (Ekind (E) = E_Constant or else Ekind (E) = E_Variable)
8291         and then Present (Size_Check_Code (E))
8292       then
8293          Remove (Size_Check_Code (E));
8294          Set_Size_Check_Code (E, Empty);
8295       end if;
8296    end Kill_Size_Check_Code;
8297
8298    --------------------------
8299    -- Known_To_Be_Assigned --
8300    --------------------------
8301
8302    function Known_To_Be_Assigned (N : Node_Id) return Boolean is
8303       P : constant Node_Id := Parent (N);
8304
8305    begin
8306       case Nkind (P) is
8307
8308          --  Test left side of assignment
8309
8310          when N_Assignment_Statement =>
8311             return N = Name (P);
8312
8313             --  Function call arguments are never lvalues
8314
8315          when N_Function_Call =>
8316             return False;
8317
8318          --  Positional parameter for procedure or accept call
8319
8320          when N_Procedure_Call_Statement |
8321               N_Accept_Statement
8322           =>
8323             declare
8324                Proc : Entity_Id;
8325                Form : Entity_Id;
8326                Act  : Node_Id;
8327
8328             begin
8329                Proc := Get_Subprogram_Entity (P);
8330
8331                if No (Proc) then
8332                   return False;
8333                end if;
8334
8335                --  If we are not a list member, something is strange, so
8336                --  be conservative and return False.
8337
8338                if not Is_List_Member (N) then
8339                   return False;
8340                end if;
8341
8342                --  We are going to find the right formal by stepping forward
8343                --  through the formals, as we step backwards in the actuals.
8344
8345                Form := First_Formal (Proc);
8346                Act  := N;
8347                loop
8348                   --  If no formal, something is weird, so be conservative
8349                   --  and return False.
8350
8351                   if No (Form) then
8352                      return False;
8353                   end if;
8354
8355                   Prev (Act);
8356                   exit when No (Act);
8357                   Next_Formal (Form);
8358                end loop;
8359
8360                return Ekind (Form) /= E_In_Parameter;
8361             end;
8362
8363          --  Named parameter for procedure or accept call
8364
8365          when N_Parameter_Association =>
8366             declare
8367                Proc : Entity_Id;
8368                Form : Entity_Id;
8369
8370             begin
8371                Proc := Get_Subprogram_Entity (Parent (P));
8372
8373                if No (Proc) then
8374                   return False;
8375                end if;
8376
8377                --  Loop through formals to find the one that matches
8378
8379                Form := First_Formal (Proc);
8380                loop
8381                   --  If no matching formal, that's peculiar, some kind of
8382                   --  previous error, so return False to be conservative.
8383
8384                   if No (Form) then
8385                      return False;
8386                   end if;
8387
8388                   --  Else test for match
8389
8390                   if Chars (Form) = Chars (Selector_Name (P)) then
8391                      return Ekind (Form) /= E_In_Parameter;
8392                   end if;
8393
8394                   Next_Formal (Form);
8395                end loop;
8396             end;
8397
8398          --  Test for appearing in a conversion that itself appears
8399          --  in an lvalue context, since this should be an lvalue.
8400
8401          when N_Type_Conversion =>
8402             return Known_To_Be_Assigned (P);
8403
8404          --  All other references are definitely not known to be modifications
8405
8406          when others =>
8407             return False;
8408
8409       end case;
8410    end Known_To_Be_Assigned;
8411
8412    ---------------------------
8413    -- Last_Source_Statement --
8414    ---------------------------
8415
8416    function Last_Source_Statement (HSS : Node_Id) return Node_Id is
8417       N : Node_Id;
8418
8419    begin
8420       N := Last (Statements (HSS));
8421       while Present (N) loop
8422          exit when Comes_From_Source (N);
8423          Prev (N);
8424       end loop;
8425
8426       return N;
8427    end Last_Source_Statement;
8428
8429    ----------------------------------
8430    -- Matching_Static_Array_Bounds --
8431    ----------------------------------
8432
8433    function Matching_Static_Array_Bounds
8434      (L_Typ : Node_Id;
8435       R_Typ : Node_Id) return Boolean
8436    is
8437       L_Ndims : constant Nat := Number_Dimensions (L_Typ);
8438       R_Ndims : constant Nat := Number_Dimensions (R_Typ);
8439
8440       L_Index : Node_Id;
8441       R_Index : Node_Id;
8442       L_Low   : Node_Id;
8443       L_High  : Node_Id;
8444       L_Len   : Uint;
8445       R_Low   : Node_Id;
8446       R_High  : Node_Id;
8447       R_Len   : Uint;
8448
8449    begin
8450       if L_Ndims /= R_Ndims then
8451          return False;
8452       end if;
8453
8454       --  Unconstrained types do not have static bounds
8455
8456       if not Is_Constrained (L_Typ) or else not Is_Constrained (R_Typ) then
8457          return False;
8458       end if;
8459
8460       --  First treat specially the first dimension, as the lower bound and
8461       --  length of string literals are not stored like those of arrays.
8462
8463       if Ekind (L_Typ) = E_String_Literal_Subtype then
8464          L_Low := String_Literal_Low_Bound (L_Typ);
8465          L_Len := String_Literal_Length (L_Typ);
8466       else
8467          L_Index := First_Index (L_Typ);
8468          Get_Index_Bounds (L_Index, L_Low, L_High);
8469
8470          if         Is_OK_Static_Expression (L_Low)
8471            and then Is_OK_Static_Expression (L_High)
8472          then
8473             if Expr_Value (L_High) < Expr_Value (L_Low) then
8474                L_Len := Uint_0;
8475             else
8476                L_Len := (Expr_Value (L_High) - Expr_Value (L_Low)) + 1;
8477             end if;
8478          else
8479             return False;
8480          end if;
8481       end if;
8482
8483       if Ekind (R_Typ) = E_String_Literal_Subtype then
8484          R_Low := String_Literal_Low_Bound (R_Typ);
8485          R_Len := String_Literal_Length (R_Typ);
8486       else
8487          R_Index := First_Index (R_Typ);
8488          Get_Index_Bounds (R_Index, R_Low, R_High);
8489
8490          if         Is_OK_Static_Expression (R_Low)
8491            and then Is_OK_Static_Expression (R_High)
8492          then
8493             if Expr_Value (R_High) < Expr_Value (R_Low) then
8494                R_Len := Uint_0;
8495             else
8496                R_Len := (Expr_Value (R_High) - Expr_Value (R_Low)) + 1;
8497             end if;
8498          else
8499             return False;
8500          end if;
8501       end if;
8502
8503       if         Is_OK_Static_Expression (L_Low)
8504         and then Is_OK_Static_Expression (R_Low)
8505         and then Expr_Value (L_Low) = Expr_Value (R_Low)
8506         and then L_Len = R_Len
8507       then
8508          null;
8509       else
8510          return False;
8511       end if;
8512
8513       --  Then treat all other dimensions
8514
8515       for Indx in 2 .. L_Ndims loop
8516          Next (L_Index);
8517          Next (R_Index);
8518
8519          Get_Index_Bounds (L_Index, L_Low, L_High);
8520          Get_Index_Bounds (R_Index, R_Low, R_High);
8521
8522          if         Is_OK_Static_Expression (L_Low)
8523            and then Is_OK_Static_Expression (L_High)
8524            and then Is_OK_Static_Expression (R_Low)
8525            and then Is_OK_Static_Expression (R_High)
8526            and then Expr_Value (L_Low)  = Expr_Value (R_Low)
8527            and then Expr_Value (L_High) = Expr_Value (R_High)
8528          then
8529             null;
8530          else
8531             return False;
8532          end if;
8533       end loop;
8534
8535       --  If we fall through the loop, all indexes matched
8536
8537       return True;
8538    end Matching_Static_Array_Bounds;
8539
8540    -------------------
8541    -- May_Be_Lvalue --
8542    -------------------
8543
8544    function May_Be_Lvalue (N : Node_Id) return Boolean is
8545       P : constant Node_Id := Parent (N);
8546
8547    begin
8548       case Nkind (P) is
8549
8550          --  Test left side of assignment
8551
8552          when N_Assignment_Statement =>
8553             return N = Name (P);
8554
8555          --  Test prefix of component or attribute. Note that the prefix of an
8556          --  explicit or implicit dereference cannot be an l-value.
8557
8558          when N_Attribute_Reference =>
8559             return N = Prefix (P)
8560               and then Name_Implies_Lvalue_Prefix (Attribute_Name (P));
8561
8562          --  For an expanded name, the name is an lvalue if the expanded name
8563          --  is an lvalue, but the prefix is never an lvalue, since it is just
8564          --  the scope where the name is found.
8565
8566          when N_Expanded_Name        =>
8567             if N = Prefix (P) then
8568                return May_Be_Lvalue (P);
8569             else
8570                return False;
8571             end if;
8572
8573          --  For a selected component A.B, A is certainly an lvalue if A.B is.
8574          --  B is a little interesting, if we have A.B := 3, there is some
8575          --  discussion as to whether B is an lvalue or not, we choose to say
8576          --  it is. Note however that A is not an lvalue if it is of an access
8577          --  type since this is an implicit dereference.
8578
8579          when N_Selected_Component   =>
8580             if N = Prefix (P)
8581               and then Present (Etype (N))
8582               and then Is_Access_Type (Etype (N))
8583             then
8584                return False;
8585             else
8586                return May_Be_Lvalue (P);
8587             end if;
8588
8589          --  For an indexed component or slice, the index or slice bounds is
8590          --  never an lvalue. The prefix is an lvalue if the indexed component
8591          --  or slice is an lvalue, except if it is an access type, where we
8592          --  have an implicit dereference.
8593
8594          when N_Indexed_Component    =>
8595             if N /= Prefix (P)
8596               or else (Present (Etype (N)) and then Is_Access_Type (Etype (N)))
8597             then
8598                return False;
8599             else
8600                return May_Be_Lvalue (P);
8601             end if;
8602
8603          --  Prefix of a reference is an lvalue if the reference is an lvalue
8604
8605          when N_Reference            =>
8606             return May_Be_Lvalue (P);
8607
8608          --  Prefix of explicit dereference is never an lvalue
8609
8610          when N_Explicit_Dereference =>
8611             return False;
8612
8613          --  Positional parameter for subprogram, entry, or accept call.
8614          --  In older versions of Ada function call arguments are never
8615          --  lvalues. In Ada 2012 functions can have in-out parameters.
8616
8617          when N_Function_Call            |
8618               N_Procedure_Call_Statement |
8619               N_Entry_Call_Statement     |
8620               N_Accept_Statement
8621          =>
8622             if Nkind (P) = N_Function_Call
8623               and then Ada_Version < Ada_2012
8624             then
8625                return False;
8626             end if;
8627
8628             --  The following mechanism is clumsy and fragile. A single
8629             --  flag set in Resolve_Actuals would be preferable ???
8630
8631             declare
8632                Proc : Entity_Id;
8633                Form : Entity_Id;
8634                Act  : Node_Id;
8635
8636             begin
8637                Proc := Get_Subprogram_Entity (P);
8638
8639                if No (Proc) then
8640                   return True;
8641                end if;
8642
8643                --  If we are not a list member, something is strange, so
8644                --  be conservative and return True.
8645
8646                if not Is_List_Member (N) then
8647                   return True;
8648                end if;
8649
8650                --  We are going to find the right formal by stepping forward
8651                --  through the formals, as we step backwards in the actuals.
8652
8653                Form := First_Formal (Proc);
8654                Act  := N;
8655                loop
8656                   --  If no formal, something is weird, so be conservative
8657                   --  and return True.
8658
8659                   if No (Form) then
8660                      return True;
8661                   end if;
8662
8663                   Prev (Act);
8664                   exit when No (Act);
8665                   Next_Formal (Form);
8666                end loop;
8667
8668                return Ekind (Form) /= E_In_Parameter;
8669             end;
8670
8671          --  Named parameter for procedure or accept call
8672
8673          when N_Parameter_Association =>
8674             declare
8675                Proc : Entity_Id;
8676                Form : Entity_Id;
8677
8678             begin
8679                Proc := Get_Subprogram_Entity (Parent (P));
8680
8681                if No (Proc) then
8682                   return True;
8683                end if;
8684
8685                --  Loop through formals to find the one that matches
8686
8687                Form := First_Formal (Proc);
8688                loop
8689                   --  If no matching formal, that's peculiar, some kind of
8690                   --  previous error, so return True to be conservative.
8691
8692                   if No (Form) then
8693                      return True;
8694                   end if;
8695
8696                   --  Else test for match
8697
8698                   if Chars (Form) = Chars (Selector_Name (P)) then
8699                      return Ekind (Form) /= E_In_Parameter;
8700                   end if;
8701
8702                   Next_Formal (Form);
8703                end loop;
8704             end;
8705
8706          --  Test for appearing in a conversion that itself appears in an
8707          --  lvalue context, since this should be an lvalue.
8708
8709          when N_Type_Conversion =>
8710             return May_Be_Lvalue (P);
8711
8712          --  Test for appearance in object renaming declaration
8713
8714          when N_Object_Renaming_Declaration =>
8715             return True;
8716
8717          --  All other references are definitely not lvalues
8718
8719          when others =>
8720             return False;
8721
8722       end case;
8723    end May_Be_Lvalue;
8724
8725    -----------------------
8726    -- Mark_Coextensions --
8727    -----------------------
8728
8729    procedure Mark_Coextensions (Context_Nod : Node_Id; Root_Nod : Node_Id) is
8730       Is_Dynamic : Boolean;
8731       --  Indicates whether the context causes nested coextensions to be
8732       --  dynamic or static
8733
8734       function Mark_Allocator (N : Node_Id) return Traverse_Result;
8735       --  Recognize an allocator node and label it as a dynamic coextension
8736
8737       --------------------
8738       -- Mark_Allocator --
8739       --------------------
8740
8741       function Mark_Allocator (N : Node_Id) return Traverse_Result is
8742       begin
8743          if Nkind (N) = N_Allocator then
8744             if Is_Dynamic then
8745                Set_Is_Dynamic_Coextension (N);
8746
8747             --  If the allocator expression is potentially dynamic, it may
8748             --  be expanded out of order and require dynamic allocation
8749             --  anyway, so we treat the coextension itself as dynamic.
8750             --  Potential optimization ???
8751
8752             elsif Nkind (Expression (N)) = N_Qualified_Expression
8753               and then Nkind (Expression (Expression (N))) = N_Op_Concat
8754             then
8755                Set_Is_Dynamic_Coextension (N);
8756
8757             else
8758                Set_Is_Static_Coextension (N);
8759             end if;
8760          end if;
8761
8762          return OK;
8763       end Mark_Allocator;
8764
8765       procedure Mark_Allocators is new Traverse_Proc (Mark_Allocator);
8766
8767    --  Start of processing Mark_Coextensions
8768
8769    begin
8770       case Nkind (Context_Nod) is
8771          when N_Assignment_Statement    |
8772               N_Simple_Return_Statement =>
8773             Is_Dynamic := Nkind (Expression (Context_Nod)) = N_Allocator;
8774
8775          when N_Object_Declaration =>
8776             Is_Dynamic := Nkind (Root_Nod) = N_Allocator;
8777
8778          --  This routine should not be called for constructs which may not
8779          --  contain coextensions.
8780
8781          when others =>
8782             raise Program_Error;
8783       end case;
8784
8785       Mark_Allocators (Root_Nod);
8786    end Mark_Coextensions;
8787
8788    ----------------------
8789    -- Needs_One_Actual --
8790    ----------------------
8791
8792    function Needs_One_Actual (E : Entity_Id) return Boolean is
8793       Formal : Entity_Id;
8794
8795    begin
8796       if Ada_Version >= Ada_2005
8797         and then Present (First_Formal (E))
8798       then
8799          Formal := Next_Formal (First_Formal (E));
8800          while Present (Formal) loop
8801             if No (Default_Value (Formal)) then
8802                return False;
8803             end if;
8804
8805             Next_Formal (Formal);
8806          end loop;
8807
8808          return True;
8809
8810       else
8811          return False;
8812       end if;
8813    end Needs_One_Actual;
8814
8815    ------------------------
8816    -- New_Copy_List_Tree --
8817    ------------------------
8818
8819    function New_Copy_List_Tree (List : List_Id) return List_Id is
8820       NL : List_Id;
8821       E  : Node_Id;
8822
8823    begin
8824       if List = No_List then
8825          return No_List;
8826
8827       else
8828          NL := New_List;
8829          E := First (List);
8830
8831          while Present (E) loop
8832             Append (New_Copy_Tree (E), NL);
8833             E := Next (E);
8834          end loop;
8835
8836          return NL;
8837       end if;
8838    end New_Copy_List_Tree;
8839
8840    -------------------
8841    -- New_Copy_Tree --
8842    -------------------
8843
8844    use Atree.Unchecked_Access;
8845    use Atree_Private_Part;
8846
8847    --  Our approach here requires a two pass traversal of the tree. The
8848    --  first pass visits all nodes that eventually will be copied looking
8849    --  for defining Itypes. If any defining Itypes are found, then they are
8850    --  copied, and an entry is added to the replacement map. In the second
8851    --  phase, the tree is copied, using the replacement map to replace any
8852    --  Itype references within the copied tree.
8853
8854    --  The following hash tables are used if the Map supplied has more
8855    --  than hash threshold entries to speed up access to the map. If
8856    --  there are fewer entries, then the map is searched sequentially
8857    --  (because setting up a hash table for only a few entries takes
8858    --  more time than it saves.
8859
8860    function New_Copy_Hash (E : Entity_Id) return NCT_Header_Num;
8861    --  Hash function used for hash operations
8862
8863    -------------------
8864    -- New_Copy_Hash --
8865    -------------------
8866
8867    function New_Copy_Hash (E : Entity_Id) return NCT_Header_Num is
8868    begin
8869       return Nat (E) mod (NCT_Header_Num'Last + 1);
8870    end New_Copy_Hash;
8871
8872    ---------------
8873    -- NCT_Assoc --
8874    ---------------
8875
8876    --  The hash table NCT_Assoc associates old entities in the table
8877    --  with their corresponding new entities (i.e. the pairs of entries
8878    --  presented in the original Map argument are Key-Element pairs).
8879
8880    package NCT_Assoc is new Simple_HTable (
8881      Header_Num => NCT_Header_Num,
8882      Element    => Entity_Id,
8883      No_Element => Empty,
8884      Key        => Entity_Id,
8885      Hash       => New_Copy_Hash,
8886      Equal      => Types."=");
8887
8888    ---------------------
8889    -- NCT_Itype_Assoc --
8890    ---------------------
8891
8892    --  The hash table NCT_Itype_Assoc contains entries only for those
8893    --  old nodes which have a non-empty Associated_Node_For_Itype set.
8894    --  The key is the associated node, and the element is the new node
8895    --  itself (NOT the associated node for the new node).
8896
8897    package NCT_Itype_Assoc is new Simple_HTable (
8898      Header_Num => NCT_Header_Num,
8899      Element    => Entity_Id,
8900      No_Element => Empty,
8901      Key        => Entity_Id,
8902      Hash       => New_Copy_Hash,
8903      Equal      => Types."=");
8904
8905    --  Start of processing for New_Copy_Tree function
8906
8907    function New_Copy_Tree
8908      (Source    : Node_Id;
8909       Map       : Elist_Id := No_Elist;
8910       New_Sloc  : Source_Ptr := No_Location;
8911       New_Scope : Entity_Id := Empty) return Node_Id
8912    is
8913       Actual_Map : Elist_Id := Map;
8914       --  This is the actual map for the copy. It is initialized with the
8915       --  given elements, and then enlarged as required for Itypes that are
8916       --  copied during the first phase of the copy operation. The visit
8917       --  procedures add elements to this map as Itypes are encountered.
8918       --  The reason we cannot use Map directly, is that it may well be
8919       --  (and normally is) initialized to No_Elist, and if we have mapped
8920       --  entities, we have to reset it to point to a real Elist.
8921
8922       function Assoc (N : Node_Or_Entity_Id) return Node_Id;
8923       --  Called during second phase to map entities into their corresponding
8924       --  copies using Actual_Map. If the argument is not an entity, or is not
8925       --  in Actual_Map, then it is returned unchanged.
8926
8927       procedure Build_NCT_Hash_Tables;
8928       --  Builds hash tables (number of elements >= threshold value)
8929
8930       function Copy_Elist_With_Replacement
8931         (Old_Elist : Elist_Id) return Elist_Id;
8932       --  Called during second phase to copy element list doing replacements
8933
8934       procedure Copy_Itype_With_Replacement (New_Itype : Entity_Id);
8935       --  Called during the second phase to process a copied Itype. The actual
8936       --  copy happened during the first phase (so that we could make the entry
8937       --  in the mapping), but we still have to deal with the descendents of
8938       --  the copied Itype and copy them where necessary.
8939
8940       function Copy_List_With_Replacement (Old_List : List_Id) return List_Id;
8941       --  Called during second phase to copy list doing replacements
8942
8943       function Copy_Node_With_Replacement (Old_Node : Node_Id) return Node_Id;
8944       --  Called during second phase to copy node doing replacements
8945
8946       procedure Visit_Elist (E : Elist_Id);
8947       --  Called during first phase to visit all elements of an Elist
8948
8949       procedure Visit_Field (F : Union_Id; N : Node_Id);
8950       --  Visit a single field, recursing to call Visit_Node or Visit_List
8951       --  if the field is a syntactic descendent of the current node (i.e.
8952       --  its parent is Node N).
8953
8954       procedure Visit_Itype (Old_Itype : Entity_Id);
8955       --  Called during first phase to visit subsidiary fields of a defining
8956       --  Itype, and also create a copy and make an entry in the replacement
8957       --  map for the new copy.
8958
8959       procedure Visit_List (L : List_Id);
8960       --  Called during first phase to visit all elements of a List
8961
8962       procedure Visit_Node (N : Node_Or_Entity_Id);
8963       --  Called during first phase to visit a node and all its subtrees
8964
8965       -----------
8966       -- Assoc --
8967       -----------
8968
8969       function Assoc (N : Node_Or_Entity_Id) return Node_Id is
8970          E   : Elmt_Id;
8971          Ent : Entity_Id;
8972
8973       begin
8974          if not Has_Extension (N) or else No (Actual_Map) then
8975             return N;
8976
8977          elsif NCT_Hash_Tables_Used then
8978             Ent := NCT_Assoc.Get (Entity_Id (N));
8979
8980             if Present (Ent) then
8981                return Ent;
8982             else
8983                return N;
8984             end if;
8985
8986          --  No hash table used, do serial search
8987
8988          else
8989             E := First_Elmt (Actual_Map);
8990             while Present (E) loop
8991                if Node (E) = N then
8992                   return Node (Next_Elmt (E));
8993                else
8994                   E := Next_Elmt (Next_Elmt (E));
8995                end if;
8996             end loop;
8997          end if;
8998
8999          return N;
9000       end Assoc;
9001
9002       ---------------------------
9003       -- Build_NCT_Hash_Tables --
9004       ---------------------------
9005
9006       procedure Build_NCT_Hash_Tables is
9007          Elmt : Elmt_Id;
9008          Ent  : Entity_Id;
9009       begin
9010          if NCT_Hash_Table_Setup then
9011             NCT_Assoc.Reset;
9012             NCT_Itype_Assoc.Reset;
9013          end if;
9014
9015          Elmt := First_Elmt (Actual_Map);
9016          while Present (Elmt) loop
9017             Ent := Node (Elmt);
9018
9019             --  Get new entity, and associate old and new
9020
9021             Next_Elmt (Elmt);
9022             NCT_Assoc.Set (Ent, Node (Elmt));
9023
9024             if Is_Type (Ent) then
9025                declare
9026                   Anode : constant Entity_Id :=
9027                             Associated_Node_For_Itype (Ent);
9028
9029                begin
9030                   if Present (Anode) then
9031
9032                      --  Enter a link between the associated node of the
9033                      --  old Itype and the new Itype, for updating later
9034                      --  when node is copied.
9035
9036                      NCT_Itype_Assoc.Set (Anode, Node (Elmt));
9037                   end if;
9038                end;
9039             end if;
9040
9041             Next_Elmt (Elmt);
9042          end loop;
9043
9044          NCT_Hash_Tables_Used := True;
9045          NCT_Hash_Table_Setup := True;
9046       end Build_NCT_Hash_Tables;
9047
9048       ---------------------------------
9049       -- Copy_Elist_With_Replacement --
9050       ---------------------------------
9051
9052       function Copy_Elist_With_Replacement
9053         (Old_Elist : Elist_Id) return Elist_Id
9054       is
9055          M         : Elmt_Id;
9056          New_Elist : Elist_Id;
9057
9058       begin
9059          if No (Old_Elist) then
9060             return No_Elist;
9061
9062          else
9063             New_Elist := New_Elmt_List;
9064
9065             M := First_Elmt (Old_Elist);
9066             while Present (M) loop
9067                Append_Elmt (Copy_Node_With_Replacement (Node (M)), New_Elist);
9068                Next_Elmt (M);
9069             end loop;
9070          end if;
9071
9072          return New_Elist;
9073       end Copy_Elist_With_Replacement;
9074
9075       ---------------------------------
9076       -- Copy_Itype_With_Replacement --
9077       ---------------------------------
9078
9079       --  This routine exactly parallels its phase one analog Visit_Itype,
9080
9081       procedure Copy_Itype_With_Replacement (New_Itype : Entity_Id) is
9082       begin
9083          --  Translate Next_Entity, Scope and Etype fields, in case they
9084          --  reference entities that have been mapped into copies.
9085
9086          Set_Next_Entity (New_Itype, Assoc (Next_Entity (New_Itype)));
9087          Set_Etype       (New_Itype, Assoc (Etype       (New_Itype)));
9088
9089          if Present (New_Scope) then
9090             Set_Scope    (New_Itype, New_Scope);
9091          else
9092             Set_Scope    (New_Itype, Assoc (Scope       (New_Itype)));
9093          end if;
9094
9095          --  Copy referenced fields
9096
9097          if Is_Discrete_Type (New_Itype) then
9098             Set_Scalar_Range (New_Itype,
9099               Copy_Node_With_Replacement (Scalar_Range (New_Itype)));
9100
9101          elsif Has_Discriminants (Base_Type (New_Itype)) then
9102             Set_Discriminant_Constraint (New_Itype,
9103               Copy_Elist_With_Replacement
9104                 (Discriminant_Constraint (New_Itype)));
9105
9106          elsif Is_Array_Type (New_Itype) then
9107             if Present (First_Index (New_Itype)) then
9108                Set_First_Index (New_Itype,
9109                  First (Copy_List_With_Replacement
9110                          (List_Containing (First_Index (New_Itype)))));
9111             end if;
9112
9113             if Is_Packed (New_Itype) then
9114                Set_Packed_Array_Type (New_Itype,
9115                  Copy_Node_With_Replacement
9116                    (Packed_Array_Type (New_Itype)));
9117             end if;
9118          end if;
9119       end Copy_Itype_With_Replacement;
9120
9121       --------------------------------
9122       -- Copy_List_With_Replacement --
9123       --------------------------------
9124
9125       function Copy_List_With_Replacement
9126         (Old_List : List_Id) return List_Id
9127       is
9128          New_List : List_Id;
9129          E        : Node_Id;
9130
9131       begin
9132          if Old_List = No_List then
9133             return No_List;
9134
9135          else
9136             New_List := Empty_List;
9137
9138             E := First (Old_List);
9139             while Present (E) loop
9140                Append (Copy_Node_With_Replacement (E), New_List);
9141                Next (E);
9142             end loop;
9143
9144             return New_List;
9145          end if;
9146       end Copy_List_With_Replacement;
9147
9148       --------------------------------
9149       -- Copy_Node_With_Replacement --
9150       --------------------------------
9151
9152       function Copy_Node_With_Replacement
9153         (Old_Node : Node_Id) return Node_Id
9154       is
9155          New_Node : Node_Id;
9156
9157          procedure Adjust_Named_Associations
9158            (Old_Node : Node_Id;
9159             New_Node : Node_Id);
9160          --  If a call node has named associations, these are chained through
9161          --  the First_Named_Actual, Next_Named_Actual links. These must be
9162          --  propagated separately to the new parameter list, because these
9163          --  are not syntactic fields.
9164
9165          function Copy_Field_With_Replacement
9166            (Field : Union_Id) return Union_Id;
9167          --  Given Field, which is a field of Old_Node, return a copy of it
9168          --  if it is a syntactic field (i.e. its parent is Node), setting
9169          --  the parent of the copy to poit to New_Node. Otherwise returns
9170          --  the field (possibly mapped if it is an entity).
9171
9172          -------------------------------
9173          -- Adjust_Named_Associations --
9174          -------------------------------
9175
9176          procedure Adjust_Named_Associations
9177            (Old_Node : Node_Id;
9178             New_Node : Node_Id)
9179          is
9180             Old_E : Node_Id;
9181             New_E : Node_Id;
9182
9183             Old_Next : Node_Id;
9184             New_Next : Node_Id;
9185
9186          begin
9187             Old_E := First (Parameter_Associations (Old_Node));
9188             New_E := First (Parameter_Associations (New_Node));
9189             while Present (Old_E) loop
9190                if Nkind (Old_E) = N_Parameter_Association
9191                  and then Present (Next_Named_Actual (Old_E))
9192                then
9193                   if First_Named_Actual (Old_Node)
9194                     =  Explicit_Actual_Parameter (Old_E)
9195                   then
9196                      Set_First_Named_Actual
9197                        (New_Node, Explicit_Actual_Parameter (New_E));
9198                   end if;
9199
9200                   --  Now scan parameter list from the beginning,to locate
9201                   --  next named actual, which can be out of order.
9202
9203                   Old_Next := First (Parameter_Associations (Old_Node));
9204                   New_Next := First (Parameter_Associations (New_Node));
9205
9206                   while Nkind (Old_Next) /= N_Parameter_Association
9207                     or else  Explicit_Actual_Parameter (Old_Next)
9208                       /= Next_Named_Actual (Old_E)
9209                   loop
9210                      Next (Old_Next);
9211                      Next (New_Next);
9212                   end loop;
9213
9214                   Set_Next_Named_Actual
9215                     (New_E, Explicit_Actual_Parameter (New_Next));
9216                end if;
9217
9218                Next (Old_E);
9219                Next (New_E);
9220             end loop;
9221          end Adjust_Named_Associations;
9222
9223          ---------------------------------
9224          -- Copy_Field_With_Replacement --
9225          ---------------------------------
9226
9227          function Copy_Field_With_Replacement
9228            (Field : Union_Id) return Union_Id
9229          is
9230          begin
9231             if Field = Union_Id (Empty) then
9232                return Field;
9233
9234             elsif Field in Node_Range then
9235                declare
9236                   Old_N : constant Node_Id := Node_Id (Field);
9237                   New_N : Node_Id;
9238
9239                begin
9240                   --  If syntactic field, as indicated by the parent pointer
9241                   --  being set, then copy the referenced node recursively.
9242
9243                   if Parent (Old_N) = Old_Node then
9244                      New_N := Copy_Node_With_Replacement (Old_N);
9245
9246                      if New_N /= Old_N then
9247                         Set_Parent (New_N, New_Node);
9248                      end if;
9249
9250                   --  For semantic fields, update possible entity reference
9251                   --  from the replacement map.
9252
9253                   else
9254                      New_N := Assoc (Old_N);
9255                   end if;
9256
9257                   return Union_Id (New_N);
9258                end;
9259
9260             elsif Field in List_Range then
9261                declare
9262                   Old_L : constant List_Id := List_Id (Field);
9263                   New_L : List_Id;
9264
9265                begin
9266                   --  If syntactic field, as indicated by the parent pointer,
9267                   --  then recursively copy the entire referenced list.
9268
9269                   if Parent (Old_L) = Old_Node then
9270                      New_L := Copy_List_With_Replacement (Old_L);
9271                      Set_Parent (New_L, New_Node);
9272
9273                   --  For semantic list, just returned unchanged
9274
9275                   else
9276                      New_L := Old_L;
9277                   end if;
9278
9279                   return Union_Id (New_L);
9280                end;
9281
9282             --  Anything other than a list or a node is returned unchanged
9283
9284             else
9285                return Field;
9286             end if;
9287          end Copy_Field_With_Replacement;
9288
9289       --  Start of processing for Copy_Node_With_Replacement
9290
9291       begin
9292          if Old_Node <= Empty_Or_Error then
9293             return Old_Node;
9294
9295          elsif Has_Extension (Old_Node) then
9296             return Assoc (Old_Node);
9297
9298          else
9299             New_Node := New_Copy (Old_Node);
9300
9301             --  If the node we are copying is the associated node of a
9302             --  previously copied Itype, then adjust the associated node
9303             --  of the copy of that Itype accordingly.
9304
9305             if Present (Actual_Map) then
9306                declare
9307                   E   : Elmt_Id;
9308                   Ent : Entity_Id;
9309
9310                begin
9311                   --  Case of hash table used
9312
9313                   if NCT_Hash_Tables_Used then
9314                      Ent := NCT_Itype_Assoc.Get (Old_Node);
9315
9316                      if Present (Ent) then
9317                         Set_Associated_Node_For_Itype (Ent, New_Node);
9318                      end if;
9319
9320                   --  Case of no hash table used
9321
9322                   else
9323                      E := First_Elmt (Actual_Map);
9324                      while Present (E) loop
9325                         if Is_Itype (Node (E))
9326                           and then
9327                             Old_Node = Associated_Node_For_Itype (Node (E))
9328                         then
9329                            Set_Associated_Node_For_Itype
9330                              (Node (Next_Elmt (E)), New_Node);
9331                         end if;
9332
9333                         E := Next_Elmt (Next_Elmt (E));
9334                      end loop;
9335                   end if;
9336                end;
9337             end if;
9338
9339             --  Recursively copy descendents
9340
9341             Set_Field1
9342               (New_Node, Copy_Field_With_Replacement (Field1 (New_Node)));
9343             Set_Field2
9344               (New_Node, Copy_Field_With_Replacement (Field2 (New_Node)));
9345             Set_Field3
9346               (New_Node, Copy_Field_With_Replacement (Field3 (New_Node)));
9347             Set_Field4
9348               (New_Node, Copy_Field_With_Replacement (Field4 (New_Node)));
9349             Set_Field5
9350               (New_Node, Copy_Field_With_Replacement (Field5 (New_Node)));
9351
9352             --  Adjust Sloc of new node if necessary
9353
9354             if New_Sloc /= No_Location then
9355                Set_Sloc (New_Node, New_Sloc);
9356
9357                --  If we adjust the Sloc, then we are essentially making
9358                --  a completely new node, so the Comes_From_Source flag
9359                --  should be reset to the proper default value.
9360
9361                Nodes.Table (New_Node).Comes_From_Source :=
9362                  Default_Node.Comes_From_Source;
9363             end if;
9364
9365             --  If the node is call and has named associations,
9366             --  set the corresponding links in the copy.
9367
9368             if (Nkind (Old_Node) = N_Function_Call
9369                  or else Nkind (Old_Node) = N_Entry_Call_Statement
9370                  or else
9371                    Nkind (Old_Node) = N_Procedure_Call_Statement)
9372               and then Present (First_Named_Actual (Old_Node))
9373             then
9374                Adjust_Named_Associations (Old_Node, New_Node);
9375             end if;
9376
9377             --  Reset First_Real_Statement for Handled_Sequence_Of_Statements.
9378             --  The replacement mechanism applies to entities, and is not used
9379             --  here. Eventually we may need a more general graph-copying
9380             --  routine. For now, do a sequential search to find desired node.
9381
9382             if Nkind (Old_Node) = N_Handled_Sequence_Of_Statements
9383               and then Present (First_Real_Statement (Old_Node))
9384             then
9385                declare
9386                   Old_F  : constant Node_Id := First_Real_Statement (Old_Node);
9387                   N1, N2 : Node_Id;
9388
9389                begin
9390                   N1 := First (Statements (Old_Node));
9391                   N2 := First (Statements (New_Node));
9392
9393                   while N1 /= Old_F loop
9394                      Next (N1);
9395                      Next (N2);
9396                   end loop;
9397
9398                   Set_First_Real_Statement (New_Node, N2);
9399                end;
9400             end if;
9401          end if;
9402
9403          --  All done, return copied node
9404
9405          return New_Node;
9406       end Copy_Node_With_Replacement;
9407
9408       -----------------
9409       -- Visit_Elist --
9410       -----------------
9411
9412       procedure Visit_Elist (E : Elist_Id) is
9413          Elmt : Elmt_Id;
9414       begin
9415          if Present (E) then
9416             Elmt := First_Elmt (E);
9417
9418             while Elmt /= No_Elmt loop
9419                Visit_Node (Node (Elmt));
9420                Next_Elmt (Elmt);
9421             end loop;
9422          end if;
9423       end Visit_Elist;
9424
9425       -----------------
9426       -- Visit_Field --
9427       -----------------
9428
9429       procedure Visit_Field (F : Union_Id; N : Node_Id) is
9430       begin
9431          if F = Union_Id (Empty) then
9432             return;
9433
9434          elsif F in Node_Range then
9435
9436             --  Copy node if it is syntactic, i.e. its parent pointer is
9437             --  set to point to the field that referenced it (certain
9438             --  Itypes will also meet this criterion, which is fine, since
9439             --  these are clearly Itypes that do need to be copied, since
9440             --  we are copying their parent.)
9441
9442             if Parent (Node_Id (F)) = N then
9443                Visit_Node (Node_Id (F));
9444                return;
9445
9446             --  Another case, if we are pointing to an Itype, then we want
9447             --  to copy it if its associated node is somewhere in the tree
9448             --  being copied.
9449
9450             --  Note: the exclusion of self-referential copies is just an
9451             --  optimization, since the search of the already copied list
9452             --  would catch it, but it is a common case (Etype pointing
9453             --  to itself for an Itype that is a base type).
9454
9455             elsif Has_Extension (Node_Id (F))
9456               and then Is_Itype (Entity_Id (F))
9457               and then Node_Id (F) /= N
9458             then
9459                declare
9460                   P : Node_Id;
9461
9462                begin
9463                   P := Associated_Node_For_Itype (Node_Id (F));
9464                   while Present (P) loop
9465                      if P = Source then
9466                         Visit_Node (Node_Id (F));
9467                         return;
9468                      else
9469                         P := Parent (P);
9470                      end if;
9471                   end loop;
9472
9473                   --  An Itype whose parent is not being copied definitely
9474                   --  should NOT be copied, since it does not belong in any
9475                   --  sense to the copied subtree.
9476
9477                   return;
9478                end;
9479             end if;
9480
9481          elsif F in List_Range
9482            and then Parent (List_Id (F)) = N
9483          then
9484             Visit_List (List_Id (F));
9485             return;
9486          end if;
9487       end Visit_Field;
9488
9489       -----------------
9490       -- Visit_Itype --
9491       -----------------
9492
9493       procedure Visit_Itype (Old_Itype : Entity_Id) is
9494          New_Itype : Entity_Id;
9495          E         : Elmt_Id;
9496          Ent       : Entity_Id;
9497
9498       begin
9499          --  Itypes that describe the designated type of access to subprograms
9500          --  have the structure of subprogram declarations, with signatures,
9501          --  etc. Either we duplicate the signatures completely, or choose to
9502          --  share such itypes, which is fine because their elaboration will
9503          --  have no side effects.
9504
9505          if Ekind (Old_Itype) = E_Subprogram_Type then
9506             return;
9507          end if;
9508
9509          New_Itype := New_Copy (Old_Itype);
9510
9511          --  The new Itype has all the attributes of the old one, and
9512          --  we just copy the contents of the entity. However, the back-end
9513          --  needs different names for debugging purposes, so we create a
9514          --  new internal name for it in all cases.
9515
9516          Set_Chars (New_Itype, New_Internal_Name ('T'));
9517
9518          --  If our associated node is an entity that has already been copied,
9519          --  then set the associated node of the copy to point to the right
9520          --  copy. If we have copied an Itype that is itself the associated
9521          --  node of some previously copied Itype, then we set the right
9522          --  pointer in the other direction.
9523
9524          if Present (Actual_Map) then
9525
9526             --  Case of hash tables used
9527
9528             if NCT_Hash_Tables_Used then
9529
9530                Ent := NCT_Assoc.Get (Associated_Node_For_Itype (Old_Itype));
9531
9532                if Present (Ent) then
9533                   Set_Associated_Node_For_Itype (New_Itype, Ent);
9534                end if;
9535
9536                Ent := NCT_Itype_Assoc.Get (Old_Itype);
9537                if Present (Ent) then
9538                   Set_Associated_Node_For_Itype (Ent, New_Itype);
9539
9540                --  If the hash table has no association for this Itype and
9541                --  its associated node, enter one now.
9542
9543                else
9544                   NCT_Itype_Assoc.Set
9545                     (Associated_Node_For_Itype (Old_Itype), New_Itype);
9546                end if;
9547
9548             --  Case of hash tables not used
9549
9550             else
9551                E := First_Elmt (Actual_Map);
9552                while Present (E) loop
9553                   if Associated_Node_For_Itype (Old_Itype) = Node (E) then
9554                      Set_Associated_Node_For_Itype
9555                        (New_Itype, Node (Next_Elmt (E)));
9556                   end if;
9557
9558                   if Is_Type (Node (E))
9559                     and then
9560                       Old_Itype = Associated_Node_For_Itype (Node (E))
9561                   then
9562                      Set_Associated_Node_For_Itype
9563                        (Node (Next_Elmt (E)), New_Itype);
9564                   end if;
9565
9566                   E := Next_Elmt (Next_Elmt (E));
9567                end loop;
9568             end if;
9569          end if;
9570
9571          if Present (Freeze_Node (New_Itype)) then
9572             Set_Is_Frozen (New_Itype, False);
9573             Set_Freeze_Node (New_Itype, Empty);
9574          end if;
9575
9576          --  Add new association to map
9577
9578          if No (Actual_Map) then
9579             Actual_Map := New_Elmt_List;
9580          end if;
9581
9582          Append_Elmt (Old_Itype, Actual_Map);
9583          Append_Elmt (New_Itype, Actual_Map);
9584
9585          if NCT_Hash_Tables_Used then
9586             NCT_Assoc.Set (Old_Itype, New_Itype);
9587
9588          else
9589             NCT_Table_Entries := NCT_Table_Entries + 1;
9590
9591             if NCT_Table_Entries > NCT_Hash_Threshold then
9592                Build_NCT_Hash_Tables;
9593             end if;
9594          end if;
9595
9596          --  If a record subtype is simply copied, the entity list will be
9597          --  shared. Thus cloned_Subtype must be set to indicate the sharing.
9598
9599          if Ekind_In (Old_Itype, E_Record_Subtype, E_Class_Wide_Subtype) then
9600             Set_Cloned_Subtype (New_Itype, Old_Itype);
9601          end if;
9602
9603          --  Visit descendents that eventually get copied
9604
9605          Visit_Field (Union_Id (Etype (Old_Itype)), Old_Itype);
9606
9607          if Is_Discrete_Type (Old_Itype) then
9608             Visit_Field (Union_Id (Scalar_Range (Old_Itype)), Old_Itype);
9609
9610          elsif Has_Discriminants (Base_Type (Old_Itype)) then
9611             --  ??? This should involve call to Visit_Field
9612             Visit_Elist (Discriminant_Constraint (Old_Itype));
9613
9614          elsif Is_Array_Type (Old_Itype) then
9615             if Present (First_Index (Old_Itype)) then
9616                Visit_Field (Union_Id (List_Containing
9617                                 (First_Index (Old_Itype))),
9618                             Old_Itype);
9619             end if;
9620
9621             if Is_Packed (Old_Itype) then
9622                Visit_Field (Union_Id (Packed_Array_Type (Old_Itype)),
9623                             Old_Itype);
9624             end if;
9625          end if;
9626       end Visit_Itype;
9627
9628       ----------------
9629       -- Visit_List --
9630       ----------------
9631
9632       procedure Visit_List (L : List_Id) is
9633          N : Node_Id;
9634       begin
9635          if L /= No_List then
9636             N := First (L);
9637
9638             while Present (N) loop
9639                Visit_Node (N);
9640                Next (N);
9641             end loop;
9642          end if;
9643       end Visit_List;
9644
9645       ----------------
9646       -- Visit_Node --
9647       ----------------
9648
9649       procedure Visit_Node (N : Node_Or_Entity_Id) is
9650
9651       --  Start of processing for Visit_Node
9652
9653       begin
9654          --  Handle case of an Itype, which must be copied
9655
9656          if Has_Extension (N)
9657            and then Is_Itype (N)
9658          then
9659             --  Nothing to do if already in the list. This can happen with an
9660             --  Itype entity that appears more than once in the tree.
9661             --  Note that we do not want to visit descendents in this case.
9662
9663             --  Test for already in list when hash table is used
9664
9665             if NCT_Hash_Tables_Used then
9666                if Present (NCT_Assoc.Get (Entity_Id (N))) then
9667                   return;
9668                end if;
9669
9670             --  Test for already in list when hash table not used
9671
9672             else
9673                declare
9674                   E : Elmt_Id;
9675                begin
9676                   if Present (Actual_Map) then
9677                      E := First_Elmt (Actual_Map);
9678                      while Present (E) loop
9679                         if Node (E) = N then
9680                            return;
9681                         else
9682                            E := Next_Elmt (Next_Elmt (E));
9683                         end if;
9684                      end loop;
9685                   end if;
9686                end;
9687             end if;
9688
9689             Visit_Itype (N);
9690          end if;
9691
9692          --  Visit descendents
9693
9694          Visit_Field (Field1 (N), N);
9695          Visit_Field (Field2 (N), N);
9696          Visit_Field (Field3 (N), N);
9697          Visit_Field (Field4 (N), N);
9698          Visit_Field (Field5 (N), N);
9699       end Visit_Node;
9700
9701    --  Start of processing for New_Copy_Tree
9702
9703    begin
9704       Actual_Map := Map;
9705
9706       --  See if we should use hash table
9707
9708       if No (Actual_Map) then
9709          NCT_Hash_Tables_Used := False;
9710
9711       else
9712          declare
9713             Elmt : Elmt_Id;
9714
9715          begin
9716             NCT_Table_Entries := 0;
9717
9718             Elmt := First_Elmt (Actual_Map);
9719             while Present (Elmt) loop
9720                NCT_Table_Entries := NCT_Table_Entries + 1;
9721                Next_Elmt (Elmt);
9722                Next_Elmt (Elmt);
9723             end loop;
9724
9725             if NCT_Table_Entries > NCT_Hash_Threshold then
9726                Build_NCT_Hash_Tables;
9727             else
9728                NCT_Hash_Tables_Used := False;
9729             end if;
9730          end;
9731       end if;
9732
9733       --  Hash table set up if required, now start phase one by visiting
9734       --  top node (we will recursively visit the descendents).
9735
9736       Visit_Node (Source);
9737
9738       --  Now the second phase of the copy can start. First we process
9739       --  all the mapped entities, copying their descendents.
9740
9741       if Present (Actual_Map) then
9742          declare
9743             Elmt      : Elmt_Id;
9744             New_Itype : Entity_Id;
9745          begin
9746             Elmt := First_Elmt (Actual_Map);
9747             while Present (Elmt) loop
9748                Next_Elmt (Elmt);
9749                New_Itype := Node (Elmt);
9750                Copy_Itype_With_Replacement (New_Itype);
9751                Next_Elmt (Elmt);
9752             end loop;
9753          end;
9754       end if;
9755
9756       --  Now we can copy the actual tree
9757
9758       return Copy_Node_With_Replacement (Source);
9759    end New_Copy_Tree;
9760
9761    -------------------------
9762    -- New_External_Entity --
9763    -------------------------
9764
9765    function New_External_Entity
9766      (Kind         : Entity_Kind;
9767       Scope_Id     : Entity_Id;
9768       Sloc_Value   : Source_Ptr;
9769       Related_Id   : Entity_Id;
9770       Suffix       : Character;
9771       Suffix_Index : Nat := 0;
9772       Prefix       : Character := ' ') return Entity_Id
9773    is
9774       N : constant Entity_Id :=
9775             Make_Defining_Identifier (Sloc_Value,
9776               New_External_Name
9777                 (Chars (Related_Id), Suffix, Suffix_Index, Prefix));
9778
9779    begin
9780       Set_Ekind          (N, Kind);
9781       Set_Is_Internal    (N, True);
9782       Append_Entity      (N, Scope_Id);
9783       Set_Public_Status  (N);
9784
9785       if Kind in Type_Kind then
9786          Init_Size_Align (N);
9787       end if;
9788
9789       return N;
9790    end New_External_Entity;
9791
9792    -------------------------
9793    -- New_Internal_Entity --
9794    -------------------------
9795
9796    function New_Internal_Entity
9797      (Kind       : Entity_Kind;
9798       Scope_Id   : Entity_Id;
9799       Sloc_Value : Source_Ptr;
9800       Id_Char    : Character) return Entity_Id
9801    is
9802       N : constant Entity_Id := Make_Temporary (Sloc_Value, Id_Char);
9803
9804    begin
9805       Set_Ekind          (N, Kind);
9806       Set_Is_Internal    (N, True);
9807       Append_Entity      (N, Scope_Id);
9808
9809       if Kind in Type_Kind then
9810          Init_Size_Align (N);
9811       end if;
9812
9813       return N;
9814    end New_Internal_Entity;
9815
9816    -----------------
9817    -- Next_Actual --
9818    -----------------
9819
9820    function Next_Actual (Actual_Id : Node_Id) return Node_Id is
9821       N  : Node_Id;
9822
9823    begin
9824       --  If we are pointing at a positional parameter, it is a member of a
9825       --  node list (the list of parameters), and the next parameter is the
9826       --  next node on the list, unless we hit a parameter association, then
9827       --  we shift to using the chain whose head is the First_Named_Actual in
9828       --  the parent, and then is threaded using the Next_Named_Actual of the
9829       --  Parameter_Association. All this fiddling is because the original node
9830       --  list is in the textual call order, and what we need is the
9831       --  declaration order.
9832
9833       if Is_List_Member (Actual_Id) then
9834          N := Next (Actual_Id);
9835
9836          if Nkind (N) = N_Parameter_Association then
9837             return First_Named_Actual (Parent (Actual_Id));
9838          else
9839             return N;
9840          end if;
9841
9842       else
9843          return Next_Named_Actual (Parent (Actual_Id));
9844       end if;
9845    end Next_Actual;
9846
9847    procedure Next_Actual (Actual_Id : in out Node_Id) is
9848    begin
9849       Actual_Id := Next_Actual (Actual_Id);
9850    end Next_Actual;
9851
9852    -----------------------
9853    -- Normalize_Actuals --
9854    -----------------------
9855
9856    --  Chain actuals according to formals of subprogram. If there are no named
9857    --  associations, the chain is simply the list of Parameter Associations,
9858    --  since the order is the same as the declaration order. If there are named
9859    --  associations, then the First_Named_Actual field in the N_Function_Call
9860    --  or N_Procedure_Call_Statement node points to the Parameter_Association
9861    --  node for the parameter that comes first in declaration order. The
9862    --  remaining named parameters are then chained in declaration order using
9863    --  Next_Named_Actual.
9864
9865    --  This routine also verifies that the number of actuals is compatible with
9866    --  the number and default values of formals, but performs no type checking
9867    --  (type checking is done by the caller).
9868
9869    --  If the matching succeeds, Success is set to True and the caller proceeds
9870    --  with type-checking. If the match is unsuccessful, then Success is set to
9871    --  False, and the caller attempts a different interpretation, if there is
9872    --  one.
9873
9874    --  If the flag Report is on, the call is not overloaded, and a failure to
9875    --  match can be reported here, rather than in the caller.
9876
9877    procedure Normalize_Actuals
9878      (N       : Node_Id;
9879       S       : Entity_Id;
9880       Report  : Boolean;
9881       Success : out Boolean)
9882    is
9883       Actuals     : constant List_Id := Parameter_Associations (N);
9884       Actual      : Node_Id := Empty;
9885       Formal      : Entity_Id;
9886       Last        : Node_Id := Empty;
9887       First_Named : Node_Id := Empty;
9888       Found       : Boolean;
9889
9890       Formals_To_Match : Integer := 0;
9891       Actuals_To_Match : Integer := 0;
9892
9893       procedure Chain (A : Node_Id);
9894       --  Add named actual at the proper place in the list, using the
9895       --  Next_Named_Actual link.
9896
9897       function Reporting return Boolean;
9898       --  Determines if an error is to be reported. To report an error, we
9899       --  need Report to be True, and also we do not report errors caused
9900       --  by calls to init procs that occur within other init procs. Such
9901       --  errors must always be cascaded errors, since if all the types are
9902       --  declared correctly, the compiler will certainly build decent calls!
9903
9904       -----------
9905       -- Chain --
9906       -----------
9907
9908       procedure Chain (A : Node_Id) is
9909       begin
9910          if No (Last) then
9911
9912             --  Call node points to first actual in list
9913
9914             Set_First_Named_Actual (N, Explicit_Actual_Parameter (A));
9915
9916          else
9917             Set_Next_Named_Actual (Last, Explicit_Actual_Parameter (A));
9918          end if;
9919
9920          Last := A;
9921          Set_Next_Named_Actual (Last, Empty);
9922       end Chain;
9923
9924       ---------------
9925       -- Reporting --
9926       ---------------
9927
9928       function Reporting return Boolean is
9929       begin
9930          if not Report then
9931             return False;
9932
9933          elsif not Within_Init_Proc then
9934             return True;
9935
9936          elsif Is_Init_Proc (Entity (Name (N))) then
9937             return False;
9938
9939          else
9940             return True;
9941          end if;
9942       end Reporting;
9943
9944    --  Start of processing for Normalize_Actuals
9945
9946    begin
9947       if Is_Access_Type (S) then
9948
9949          --  The name in the call is a function call that returns an access
9950          --  to subprogram. The designated type has the list of formals.
9951
9952          Formal := First_Formal (Designated_Type (S));
9953       else
9954          Formal := First_Formal (S);
9955       end if;
9956
9957       while Present (Formal) loop
9958          Formals_To_Match := Formals_To_Match + 1;
9959          Next_Formal (Formal);
9960       end loop;
9961
9962       --  Find if there is a named association, and verify that no positional
9963       --  associations appear after named ones.
9964
9965       if Present (Actuals) then
9966          Actual := First (Actuals);
9967       end if;
9968
9969       while Present (Actual)
9970         and then Nkind (Actual) /= N_Parameter_Association
9971       loop
9972          Actuals_To_Match := Actuals_To_Match + 1;
9973          Next (Actual);
9974       end loop;
9975
9976       if No (Actual) and Actuals_To_Match = Formals_To_Match then
9977
9978          --  Most common case: positional notation, no defaults
9979
9980          Success := True;
9981          return;
9982
9983       elsif Actuals_To_Match > Formals_To_Match then
9984
9985          --  Too many actuals: will not work
9986
9987          if Reporting then
9988             if Is_Entity_Name (Name (N)) then
9989                Error_Msg_N ("too many arguments in call to&", Name (N));
9990             else
9991                Error_Msg_N ("too many arguments in call", N);
9992             end if;
9993          end if;
9994
9995          Success := False;
9996          return;
9997       end if;
9998
9999       First_Named := Actual;
10000
10001       while Present (Actual) loop
10002          if Nkind (Actual) /= N_Parameter_Association then
10003             Error_Msg_N
10004               ("positional parameters not allowed after named ones", Actual);
10005             Success := False;
10006             return;
10007
10008          else
10009             Actuals_To_Match := Actuals_To_Match + 1;
10010          end if;
10011
10012          Next (Actual);
10013       end loop;
10014
10015       if Present (Actuals) then
10016          Actual := First (Actuals);
10017       end if;
10018
10019       Formal := First_Formal (S);
10020       while Present (Formal) loop
10021
10022          --  Match the formals in order. If the corresponding actual is
10023          --  positional, nothing to do. Else scan the list of named actuals
10024          --  to find the one with the right name.
10025
10026          if Present (Actual)
10027            and then Nkind (Actual) /= N_Parameter_Association
10028          then
10029             Next (Actual);
10030             Actuals_To_Match := Actuals_To_Match - 1;
10031             Formals_To_Match := Formals_To_Match - 1;
10032
10033          else
10034             --  For named parameters, search the list of actuals to find
10035             --  one that matches the next formal name.
10036
10037             Actual := First_Named;
10038             Found  := False;
10039             while Present (Actual) loop
10040                if Chars (Selector_Name (Actual)) = Chars (Formal) then
10041                   Found := True;
10042                   Chain (Actual);
10043                   Actuals_To_Match := Actuals_To_Match - 1;
10044                   Formals_To_Match := Formals_To_Match - 1;
10045                   exit;
10046                end if;
10047
10048                Next (Actual);
10049             end loop;
10050
10051             if not Found then
10052                if Ekind (Formal) /= E_In_Parameter
10053                  or else No (Default_Value (Formal))
10054                then
10055                   if Reporting then
10056                      if (Comes_From_Source (S)
10057                           or else Sloc (S) = Standard_Location)
10058                        and then Is_Overloadable (S)
10059                      then
10060                         if No (Actuals)
10061                           and then
10062                            (Nkind (Parent (N)) = N_Procedure_Call_Statement
10063                              or else
10064                            (Nkind (Parent (N)) = N_Function_Call
10065                              or else
10066                             Nkind (Parent (N)) = N_Parameter_Association))
10067                           and then Ekind (S) /= E_Function
10068                         then
10069                            Set_Etype (N, Etype (S));
10070                         else
10071                            Error_Msg_Name_1 := Chars (S);
10072                            Error_Msg_Sloc := Sloc (S);
10073                            Error_Msg_NE
10074                              ("missing argument for parameter & " &
10075                                 "in call to % declared #", N, Formal);
10076                         end if;
10077
10078                      elsif Is_Overloadable (S) then
10079                         Error_Msg_Name_1 := Chars (S);
10080
10081                         --  Point to type derivation that generated the
10082                         --  operation.
10083
10084                         Error_Msg_Sloc := Sloc (Parent (S));
10085
10086                         Error_Msg_NE
10087                           ("missing argument for parameter & " &
10088                              "in call to % (inherited) #", N, Formal);
10089
10090                      else
10091                         Error_Msg_NE
10092                           ("missing argument for parameter &", N, Formal);
10093                      end if;
10094                   end if;
10095
10096                   Success := False;
10097                   return;
10098
10099                else
10100                   Formals_To_Match := Formals_To_Match - 1;
10101                end if;
10102             end if;
10103          end if;
10104
10105          Next_Formal (Formal);
10106       end loop;
10107
10108       if Formals_To_Match = 0 and then Actuals_To_Match = 0 then
10109          Success := True;
10110          return;
10111
10112       else
10113          if Reporting then
10114
10115             --  Find some superfluous named actual that did not get
10116             --  attached to the list of associations.
10117
10118             Actual := First (Actuals);
10119             while Present (Actual) loop
10120                if Nkind (Actual) = N_Parameter_Association
10121                  and then Actual /= Last
10122                  and then No (Next_Named_Actual (Actual))
10123                then
10124                   Error_Msg_N ("unmatched actual & in call",
10125                     Selector_Name (Actual));
10126                   exit;
10127                end if;
10128
10129                Next (Actual);
10130             end loop;
10131          end if;
10132
10133          Success := False;
10134          return;
10135       end if;
10136    end Normalize_Actuals;
10137
10138    --------------------------------
10139    -- Note_Possible_Modification --
10140    --------------------------------
10141
10142    procedure Note_Possible_Modification (N : Node_Id; Sure : Boolean) is
10143       Modification_Comes_From_Source : constant Boolean :=
10144                                          Comes_From_Source (Parent (N));
10145
10146       Ent : Entity_Id;
10147       Exp : Node_Id;
10148
10149    begin
10150       --  Loop to find referenced entity, if there is one
10151
10152       Exp := N;
10153       loop
10154          <<Continue>>
10155          Ent := Empty;
10156
10157          if Is_Entity_Name (Exp) then
10158             Ent := Entity (Exp);
10159
10160             --  If the entity is missing, it is an undeclared identifier,
10161             --  and there is nothing to annotate.
10162
10163             if No (Ent) then
10164                return;
10165             end if;
10166
10167          elsif Nkind (Exp) = N_Explicit_Dereference then
10168             declare
10169                P : constant Node_Id := Prefix (Exp);
10170
10171             begin
10172                if Nkind (P) = N_Selected_Component
10173                  and then Present (
10174                    Entry_Formal (Entity (Selector_Name (P))))
10175                then
10176                   --  Case of a reference to an entry formal
10177
10178                   Ent := Entry_Formal (Entity (Selector_Name (P)));
10179
10180                elsif Nkind (P) = N_Identifier
10181                  and then Nkind (Parent (Entity (P))) = N_Object_Declaration
10182                  and then Present (Expression (Parent (Entity (P))))
10183                  and then Nkind (Expression (Parent (Entity (P))))
10184                    = N_Reference
10185                then
10186                   --  Case of a reference to a value on which side effects have
10187                   --  been removed.
10188
10189                   Exp := Prefix (Expression (Parent (Entity (P))));
10190                   goto Continue;
10191
10192                else
10193                   return;
10194
10195                end if;
10196             end;
10197
10198          elsif     Nkind (Exp) = N_Type_Conversion
10199            or else Nkind (Exp) = N_Unchecked_Type_Conversion
10200          then
10201             Exp := Expression (Exp);
10202             goto Continue;
10203
10204          elsif     Nkind (Exp) = N_Slice
10205            or else Nkind (Exp) = N_Indexed_Component
10206            or else Nkind (Exp) = N_Selected_Component
10207          then
10208             Exp := Prefix (Exp);
10209             goto Continue;
10210
10211          else
10212             return;
10213          end if;
10214
10215          --  Now look for entity being referenced
10216
10217          if Present (Ent) then
10218             if Is_Object (Ent) then
10219                if Comes_From_Source (Exp)
10220                  or else Modification_Comes_From_Source
10221                then
10222                   --  Give warning if pragma unmodified given and we are
10223                   --  sure this is a modification.
10224
10225                   if Has_Pragma_Unmodified (Ent) and then Sure then
10226                      Error_Msg_NE ("?pragma Unmodified given for &!", N, Ent);
10227                   end if;
10228
10229                   Set_Never_Set_In_Source (Ent, False);
10230                end if;
10231
10232                Set_Is_True_Constant (Ent, False);
10233                Set_Current_Value    (Ent, Empty);
10234                Set_Is_Known_Null    (Ent, False);
10235
10236                if not Can_Never_Be_Null (Ent) then
10237                   Set_Is_Known_Non_Null (Ent, False);
10238                end if;
10239
10240                --  Follow renaming chain
10241
10242                if (Ekind (Ent) = E_Variable or else Ekind (Ent) = E_Constant)
10243                  and then Present (Renamed_Object (Ent))
10244                then
10245                   Exp := Renamed_Object (Ent);
10246                   goto Continue;
10247                end if;
10248
10249                --  Generate a reference only if the assignment comes from
10250                --  source. This excludes, for example, calls to a dispatching
10251                --  assignment operation when the left-hand side is tagged.
10252
10253                if Modification_Comes_From_Source then
10254                   Generate_Reference (Ent, Exp, 'm');
10255
10256                   --  If the target of the assignment is the bound variable
10257                   --  in an iterator, indicate that the corresponding array
10258                   --  or container is also modified.
10259
10260                   if Ada_Version >= Ada_2012
10261                     and then
10262                       Nkind (Parent (Ent)) = N_Iterator_Specification
10263                   then
10264                      declare
10265                         Domain : constant Node_Id := Name (Parent (Ent));
10266
10267                      begin
10268                         --  TBD : in the full version of the construct, the
10269                         --  domain of iteration can be given by an expression.
10270
10271                         if Is_Entity_Name (Domain) then
10272                            Generate_Reference      (Entity (Domain), Exp, 'm');
10273                            Set_Is_True_Constant    (Entity (Domain), False);
10274                            Set_Never_Set_In_Source (Entity (Domain), False);
10275                         end if;
10276                      end;
10277                   end if;
10278                end if;
10279
10280                Check_Nested_Access (Ent);
10281             end if;
10282
10283             Kill_Checks (Ent);
10284
10285             --  If we are sure this is a modification from source, and we know
10286             --  this modifies a constant, then give an appropriate warning.
10287
10288             if Overlays_Constant (Ent)
10289               and then Modification_Comes_From_Source
10290               and then Sure
10291             then
10292                declare
10293                   A : constant Node_Id := Address_Clause (Ent);
10294                begin
10295                   if Present (A) then
10296                      declare
10297                         Exp : constant Node_Id := Expression (A);
10298                      begin
10299                         if Nkind (Exp) = N_Attribute_Reference
10300                           and then Attribute_Name (Exp) = Name_Address
10301                           and then Is_Entity_Name (Prefix (Exp))
10302                         then
10303                            Error_Msg_Sloc := Sloc (A);
10304                            Error_Msg_NE
10305                              ("constant& may be modified via address clause#?",
10306                               N, Entity (Prefix (Exp)));
10307                         end if;
10308                      end;
10309                   end if;
10310                end;
10311             end if;
10312
10313             return;
10314          end if;
10315       end loop;
10316    end Note_Possible_Modification;
10317
10318    -------------------------
10319    -- Object_Access_Level --
10320    -------------------------
10321
10322    function Object_Access_Level (Obj : Node_Id) return Uint is
10323       E : Entity_Id;
10324
10325    --  Returns the static accessibility level of the view denoted by Obj. Note
10326    --  that the value returned is the result of a call to Scope_Depth. Only
10327    --  scope depths associated with dynamic scopes can actually be returned.
10328    --  Since only relative levels matter for accessibility checking, the fact
10329    --  that the distance between successive levels of accessibility is not
10330    --  always one is immaterial (invariant: if level(E2) is deeper than
10331    --  level(E1), then Scope_Depth(E1) < Scope_Depth(E2)).
10332
10333       function Reference_To (Obj : Node_Id) return Node_Id;
10334       --  An explicit dereference is created when removing side-effects from
10335       --  expressions for constraint checking purposes. In this case a local
10336       --  access type is created for it. The correct access level is that of
10337       --  the original source node. We detect this case by noting that the
10338       --  prefix of the dereference is created by an object declaration whose
10339       --  initial expression is a reference.
10340
10341       ------------------
10342       -- Reference_To --
10343       ------------------
10344
10345       function Reference_To (Obj : Node_Id) return Node_Id is
10346          Pref : constant Node_Id := Prefix (Obj);
10347       begin
10348          if Is_Entity_Name (Pref)
10349            and then Nkind (Parent (Entity (Pref))) = N_Object_Declaration
10350            and then Present (Expression (Parent (Entity (Pref))))
10351            and then Nkind (Expression (Parent (Entity (Pref)))) = N_Reference
10352          then
10353             return (Prefix (Expression (Parent (Entity (Pref)))));
10354          else
10355             return Empty;
10356          end if;
10357       end Reference_To;
10358
10359    --  Start of processing for Object_Access_Level
10360
10361    begin
10362       if Is_Entity_Name (Obj) then
10363          E := Entity (Obj);
10364
10365          if Is_Prival (E) then
10366             E := Prival_Link (E);
10367          end if;
10368
10369          --  If E is a type then it denotes a current instance. For this case
10370          --  we add one to the normal accessibility level of the type to ensure
10371          --  that current instances are treated as always being deeper than
10372          --  than the level of any visible named access type (see 3.10.2(21)).
10373
10374          if Is_Type (E) then
10375             return Type_Access_Level (E) +  1;
10376
10377          elsif Present (Renamed_Object (E)) then
10378             return Object_Access_Level (Renamed_Object (E));
10379
10380          --  Similarly, if E is a component of the current instance of a
10381          --  protected type, any instance of it is assumed to be at a deeper
10382          --  level than the type. For a protected object (whose type is an
10383          --  anonymous protected type) its components are at the same level
10384          --  as the type itself.
10385
10386          elsif not Is_Overloadable (E)
10387            and then Ekind (Scope (E)) = E_Protected_Type
10388            and then Comes_From_Source (Scope (E))
10389          then
10390             return Type_Access_Level (Scope (E)) + 1;
10391
10392          else
10393             return Scope_Depth (Enclosing_Dynamic_Scope (E));
10394          end if;
10395
10396       elsif Nkind (Obj) = N_Selected_Component then
10397          if Is_Access_Type (Etype (Prefix (Obj))) then
10398             return Type_Access_Level (Etype (Prefix (Obj)));
10399          else
10400             return Object_Access_Level (Prefix (Obj));
10401          end if;
10402
10403       elsif Nkind (Obj) = N_Indexed_Component then
10404          if Is_Access_Type (Etype (Prefix (Obj))) then
10405             return Type_Access_Level (Etype (Prefix (Obj)));
10406          else
10407             return Object_Access_Level (Prefix (Obj));
10408          end if;
10409
10410       elsif Nkind (Obj) = N_Explicit_Dereference then
10411
10412          --  If the prefix is a selected access discriminant then we make a
10413          --  recursive call on the prefix, which will in turn check the level
10414          --  of the prefix object of the selected discriminant.
10415
10416          if Nkind (Prefix (Obj)) = N_Selected_Component
10417            and then Ekind (Etype (Prefix (Obj))) = E_Anonymous_Access_Type
10418            and then
10419              Ekind (Entity (Selector_Name (Prefix (Obj)))) = E_Discriminant
10420          then
10421             return Object_Access_Level (Prefix (Obj));
10422
10423          elsif not (Comes_From_Source (Obj)) then
10424             declare
10425                Ref : constant Node_Id := Reference_To (Obj);
10426             begin
10427                if Present (Ref) then
10428                   return Object_Access_Level (Ref);
10429                else
10430                   return Type_Access_Level (Etype (Prefix (Obj)));
10431                end if;
10432             end;
10433
10434          else
10435             return Type_Access_Level (Etype (Prefix (Obj)));
10436          end if;
10437
10438       elsif Nkind (Obj) = N_Type_Conversion
10439         or else Nkind (Obj) = N_Unchecked_Type_Conversion
10440       then
10441          return Object_Access_Level (Expression (Obj));
10442
10443       elsif Nkind (Obj) = N_Function_Call then
10444
10445          --  Function results are objects, so we get either the access level of
10446          --  the function or, in the case of an indirect call, the level of the
10447          --  access-to-subprogram type. (This code is used for Ada 95, but it
10448          --  looks wrong, because it seems that we should be checking the level
10449          --  of the call itself, even for Ada 95. However, using the Ada 2005
10450          --  version of the code causes regressions in several tests that are
10451          --  compiled with -gnat95. ???)
10452
10453          if Ada_Version < Ada_2005 then
10454             if Is_Entity_Name (Name (Obj)) then
10455                return Subprogram_Access_Level (Entity (Name (Obj)));
10456             else
10457                return Type_Access_Level (Etype (Prefix (Name (Obj))));
10458             end if;
10459
10460          --  For Ada 2005, the level of the result object of a function call is
10461          --  defined to be the level of the call's innermost enclosing master.
10462          --  We determine that by querying the depth of the innermost enclosing
10463          --  dynamic scope.
10464
10465          else
10466             Return_Master_Scope_Depth_Of_Call : declare
10467
10468                function Innermost_Master_Scope_Depth
10469                  (N : Node_Id) return Uint;
10470                --  Returns the scope depth of the given node's innermost
10471                --  enclosing dynamic scope (effectively the accessibility
10472                --  level of the innermost enclosing master).
10473
10474                ----------------------------------
10475                -- Innermost_Master_Scope_Depth --
10476                ----------------------------------
10477
10478                function Innermost_Master_Scope_Depth
10479                  (N : Node_Id) return Uint
10480                is
10481                   Node_Par : Node_Id := Parent (N);
10482
10483                begin
10484                   --  Locate the nearest enclosing node (by traversing Parents)
10485                   --  that Defining_Entity can be applied to, and return the
10486                   --  depth of that entity's nearest enclosing dynamic scope.
10487
10488                   while Present (Node_Par) loop
10489                      case Nkind (Node_Par) is
10490                         when N_Component_Declaration           |
10491                              N_Entry_Declaration               |
10492                              N_Formal_Object_Declaration       |
10493                              N_Formal_Type_Declaration         |
10494                              N_Full_Type_Declaration           |
10495                              N_Incomplete_Type_Declaration     |
10496                              N_Loop_Parameter_Specification    |
10497                              N_Object_Declaration              |
10498                              N_Protected_Type_Declaration      |
10499                              N_Private_Extension_Declaration   |
10500                              N_Private_Type_Declaration        |
10501                              N_Subtype_Declaration             |
10502                              N_Function_Specification          |
10503                              N_Procedure_Specification         |
10504                              N_Task_Type_Declaration           |
10505                              N_Body_Stub                       |
10506                              N_Generic_Instantiation           |
10507                              N_Proper_Body                     |
10508                              N_Implicit_Label_Declaration      |
10509                              N_Package_Declaration             |
10510                              N_Single_Task_Declaration         |
10511                              N_Subprogram_Declaration          |
10512                              N_Generic_Declaration             |
10513                              N_Renaming_Declaration            |
10514                              N_Block_Statement                 |
10515                              N_Formal_Subprogram_Declaration   |
10516                              N_Abstract_Subprogram_Declaration |
10517                              N_Entry_Body                      |
10518                              N_Exception_Declaration           |
10519                              N_Formal_Package_Declaration      |
10520                              N_Number_Declaration              |
10521                              N_Package_Specification           |
10522                              N_Parameter_Specification         |
10523                              N_Single_Protected_Declaration    |
10524                              N_Subunit                         =>
10525
10526                            return Scope_Depth
10527                                     (Nearest_Dynamic_Scope
10528                                        (Defining_Entity (Node_Par)));
10529
10530                         when others =>
10531                            null;
10532                      end case;
10533
10534                      Node_Par := Parent (Node_Par);
10535                   end loop;
10536
10537                   pragma Assert (False);
10538
10539                   --  Should never reach the following return
10540
10541                   return Scope_Depth (Current_Scope) + 1;
10542                end Innermost_Master_Scope_Depth;
10543
10544             --  Start of processing for Return_Master_Scope_Depth_Of_Call
10545
10546             begin
10547                return Innermost_Master_Scope_Depth (Obj);
10548             end Return_Master_Scope_Depth_Of_Call;
10549          end if;
10550
10551       --  For convenience we handle qualified expressions, even though
10552       --  they aren't technically object names.
10553
10554       elsif Nkind (Obj) = N_Qualified_Expression then
10555          return Object_Access_Level (Expression (Obj));
10556
10557       --  Otherwise return the scope level of Standard.
10558       --  (If there are cases that fall through
10559       --  to this point they will be treated as
10560       --  having global accessibility for now. ???)
10561
10562       else
10563          return Scope_Depth (Standard_Standard);
10564       end if;
10565    end Object_Access_Level;
10566
10567    --------------------------------------
10568    -- Original_Corresponding_Operation --
10569    --------------------------------------
10570
10571    function Original_Corresponding_Operation (S : Entity_Id) return Entity_Id
10572    is
10573       Typ : constant Entity_Id := Find_Dispatching_Type (S);
10574
10575    begin
10576       --  If S is an inherited primitive S2 the original corresponding
10577       --  operation of S is the original corresponding operation of S2
10578
10579       if Present (Alias (S))
10580         and then Find_Dispatching_Type (Alias (S)) /= Typ
10581       then
10582          return Original_Corresponding_Operation (Alias (S));
10583
10584       --  If S overrides an inherited subprogram S2 the original corresponding
10585       --  operation of S is the original corresponding operation of S2
10586
10587       elsif Present (Overridden_Operation (S)) then
10588          return Original_Corresponding_Operation (Overridden_Operation (S));
10589
10590       --  otherwise it is S itself
10591
10592       else
10593          return S;
10594       end if;
10595    end Original_Corresponding_Operation;
10596
10597    -----------------------
10598    -- Private_Component --
10599    -----------------------
10600
10601    function Private_Component (Type_Id : Entity_Id) return Entity_Id is
10602       Ancestor  : constant Entity_Id := Base_Type (Type_Id);
10603
10604       function Trace_Components
10605         (T     : Entity_Id;
10606          Check : Boolean) return Entity_Id;
10607       --  Recursive function that does the work, and checks against circular
10608       --  definition for each subcomponent type.
10609
10610       ----------------------
10611       -- Trace_Components --
10612       ----------------------
10613
10614       function Trace_Components
10615          (T     : Entity_Id;
10616           Check : Boolean) return Entity_Id
10617        is
10618          Btype     : constant Entity_Id := Base_Type (T);
10619          Component : Entity_Id;
10620          P         : Entity_Id;
10621          Candidate : Entity_Id := Empty;
10622
10623       begin
10624          if Check and then Btype = Ancestor then
10625             Error_Msg_N ("circular type definition", Type_Id);
10626             return Any_Type;
10627          end if;
10628
10629          if Is_Private_Type (Btype)
10630            and then not Is_Generic_Type (Btype)
10631          then
10632             if Present (Full_View (Btype))
10633               and then Is_Record_Type (Full_View (Btype))
10634               and then not Is_Frozen (Btype)
10635             then
10636                --  To indicate that the ancestor depends on a private type, the
10637                --  current Btype is sufficient. However, to check for circular
10638                --  definition we must recurse on the full view.
10639
10640                Candidate := Trace_Components (Full_View (Btype), True);
10641
10642                if Candidate = Any_Type then
10643                   return Any_Type;
10644                else
10645                   return Btype;
10646                end if;
10647
10648             else
10649                return Btype;
10650             end if;
10651
10652          elsif Is_Array_Type (Btype) then
10653             return Trace_Components (Component_Type (Btype), True);
10654
10655          elsif Is_Record_Type (Btype) then
10656             Component := First_Entity (Btype);
10657             while Present (Component) loop
10658
10659                --  Skip anonymous types generated by constrained components
10660
10661                if not Is_Type (Component) then
10662                   P := Trace_Components (Etype (Component), True);
10663
10664                   if Present (P) then
10665                      if P = Any_Type then
10666                         return P;
10667                      else
10668                         Candidate := P;
10669                      end if;
10670                   end if;
10671                end if;
10672
10673                Next_Entity (Component);
10674             end loop;
10675
10676             return Candidate;
10677
10678          else
10679             return Empty;
10680          end if;
10681       end Trace_Components;
10682
10683    --  Start of processing for Private_Component
10684
10685    begin
10686       return Trace_Components (Type_Id, False);
10687    end Private_Component;
10688
10689    ---------------------------
10690    -- Primitive_Names_Match --
10691    ---------------------------
10692
10693    function Primitive_Names_Match (E1, E2 : Entity_Id) return Boolean is
10694
10695       function Non_Internal_Name (E : Entity_Id) return Name_Id;
10696       --  Given an internal name, returns the corresponding non-internal name
10697
10698       ------------------------
10699       --  Non_Internal_Name --
10700       ------------------------
10701
10702       function Non_Internal_Name (E : Entity_Id) return Name_Id is
10703       begin
10704          Get_Name_String (Chars (E));
10705          Name_Len := Name_Len - 1;
10706          return Name_Find;
10707       end Non_Internal_Name;
10708
10709    --  Start of processing for Primitive_Names_Match
10710
10711    begin
10712       pragma Assert (Present (E1) and then Present (E2));
10713
10714       return Chars (E1) = Chars (E2)
10715         or else
10716            (not Is_Internal_Name (Chars (E1))
10717               and then Is_Internal_Name (Chars (E2))
10718               and then Non_Internal_Name (E2) = Chars (E1))
10719         or else
10720            (not Is_Internal_Name (Chars (E2))
10721               and then Is_Internal_Name (Chars (E1))
10722               and then Non_Internal_Name (E1) = Chars (E2))
10723         or else
10724            (Is_Predefined_Dispatching_Operation (E1)
10725               and then Is_Predefined_Dispatching_Operation (E2)
10726               and then Same_TSS (E1, E2))
10727         or else
10728            (Is_Init_Proc (E1) and then Is_Init_Proc (E2));
10729    end Primitive_Names_Match;
10730
10731    -----------------------
10732    -- Process_End_Label --
10733    -----------------------
10734
10735    procedure Process_End_Label
10736      (N   : Node_Id;
10737       Typ : Character;
10738       Ent : Entity_Id)
10739    is
10740       Loc  : Source_Ptr;
10741       Nam  : Node_Id;
10742       Scop : Entity_Id;
10743
10744       Label_Ref : Boolean;
10745       --  Set True if reference to end label itself is required
10746
10747       Endl : Node_Id;
10748       --  Gets set to the operator symbol or identifier that references the
10749       --  entity Ent. For the child unit case, this is the identifier from the
10750       --  designator. For other cases, this is simply Endl.
10751
10752       procedure Generate_Parent_Ref (N : Node_Id; E : Entity_Id);
10753       --  N is an identifier node that appears as a parent unit reference in
10754       --  the case where Ent is a child unit. This procedure generates an
10755       --  appropriate cross-reference entry. E is the corresponding entity.
10756
10757       -------------------------
10758       -- Generate_Parent_Ref --
10759       -------------------------
10760
10761       procedure Generate_Parent_Ref (N : Node_Id; E : Entity_Id) is
10762       begin
10763          --  If names do not match, something weird, skip reference
10764
10765          if Chars (E) = Chars (N) then
10766
10767             --  Generate the reference. We do NOT consider this as a reference
10768             --  for unreferenced symbol purposes.
10769
10770             Generate_Reference (E, N, 'r', Set_Ref => False, Force => True);
10771
10772             if Style_Check then
10773                Style.Check_Identifier (N, E);
10774             end if;
10775          end if;
10776       end Generate_Parent_Ref;
10777
10778    --  Start of processing for Process_End_Label
10779
10780    begin
10781       --  If no node, ignore. This happens in some error situations, and
10782       --  also for some internally generated structures where no end label
10783       --  references are required in any case.
10784
10785       if No (N) then
10786          return;
10787       end if;
10788
10789       --  Nothing to do if no End_Label, happens for internally generated
10790       --  constructs where we don't want an end label reference anyway. Also
10791       --  nothing to do if Endl is a string literal, which means there was
10792       --  some prior error (bad operator symbol)
10793
10794       Endl := End_Label (N);
10795
10796       if No (Endl) or else Nkind (Endl) = N_String_Literal then
10797          return;
10798       end if;
10799
10800       --  Reference node is not in extended main source unit
10801
10802       if not In_Extended_Main_Source_Unit (N) then
10803
10804          --  Generally we do not collect references except for the extended
10805          --  main source unit. The one exception is the 'e' entry for a
10806          --  package spec, where it is useful for a client to have the
10807          --  ending information to define scopes.
10808
10809          if Typ /= 'e' then
10810             return;
10811
10812          else
10813             Label_Ref := False;
10814
10815             --  For this case, we can ignore any parent references, but we
10816             --  need the package name itself for the 'e' entry.
10817
10818             if Nkind (Endl) = N_Designator then
10819                Endl := Identifier (Endl);
10820             end if;
10821          end if;
10822
10823       --  Reference is in extended main source unit
10824
10825       else
10826          Label_Ref := True;
10827
10828          --  For designator, generate references for the parent entries
10829
10830          if Nkind (Endl) = N_Designator then
10831
10832             --  Generate references for the prefix if the END line comes from
10833             --  source (otherwise we do not need these references) We climb the
10834             --  scope stack to find the expected entities.
10835
10836             if Comes_From_Source (Endl) then
10837                Nam  := Name (Endl);
10838                Scop := Current_Scope;
10839                while Nkind (Nam) = N_Selected_Component loop
10840                   Scop := Scope (Scop);
10841                   exit when No (Scop);
10842                   Generate_Parent_Ref (Selector_Name (Nam), Scop);
10843                   Nam := Prefix (Nam);
10844                end loop;
10845
10846                if Present (Scop) then
10847                   Generate_Parent_Ref (Nam, Scope (Scop));
10848                end if;
10849             end if;
10850
10851             Endl := Identifier (Endl);
10852          end if;
10853       end if;
10854
10855       --  If the end label is not for the given entity, then either we have
10856       --  some previous error, or this is a generic instantiation for which
10857       --  we do not need to make a cross-reference in this case anyway. In
10858       --  either case we simply ignore the call.
10859
10860       if Chars (Ent) /= Chars (Endl) then
10861          return;
10862       end if;
10863
10864       --  If label was really there, then generate a normal reference and then
10865       --  adjust the location in the end label to point past the name (which
10866       --  should almost always be the semicolon).
10867
10868       Loc := Sloc (Endl);
10869
10870       if Comes_From_Source (Endl) then
10871
10872          --  If a label reference is required, then do the style check and
10873          --  generate an l-type cross-reference entry for the label
10874
10875          if Label_Ref then
10876             if Style_Check then
10877                Style.Check_Identifier (Endl, Ent);
10878             end if;
10879
10880             Generate_Reference (Ent, Endl, 'l', Set_Ref => False);
10881          end if;
10882
10883          --  Set the location to point past the label (normally this will
10884          --  mean the semicolon immediately following the label). This is
10885          --  done for the sake of the 'e' or 't' entry generated below.
10886
10887          Get_Decoded_Name_String (Chars (Endl));
10888          Set_Sloc (Endl, Sloc (Endl) + Source_Ptr (Name_Len));
10889
10890       else
10891          --  In SPARK mode, no missing label is allowed for packages and
10892          --  subprogram bodies. Detect those cases by testing whether
10893          --  Process_End_Label was called for a body (Typ = 't') or a package.
10894
10895          if (SPARK_Mode or else Restriction_Check_Required (SPARK))
10896            and then (Typ = 't' or else Ekind (Ent) = E_Package)
10897          then
10898             Error_Msg_Node_1 := Endl;
10899             Check_SPARK_Restriction ("`END &` required", Endl, Force => True);
10900          end if;
10901       end if;
10902
10903       --  Now generate the e/t reference
10904
10905       Generate_Reference (Ent, Endl, Typ, Set_Ref => False, Force => True);
10906
10907       --  Restore Sloc, in case modified above, since we have an identifier
10908       --  and the normal Sloc should be left set in the tree.
10909
10910       Set_Sloc (Endl, Loc);
10911    end Process_End_Label;
10912
10913    ------------------------------------
10914    -- References_Generic_Formal_Type --
10915    ------------------------------------
10916
10917    function References_Generic_Formal_Type (N : Node_Id) return Boolean is
10918
10919       function Process (N : Node_Id) return Traverse_Result;
10920       --  Process one node in search for generic formal type
10921
10922       -------------
10923       -- Process --
10924       -------------
10925
10926       function Process (N : Node_Id) return Traverse_Result is
10927       begin
10928          if Nkind (N) in N_Has_Entity then
10929             declare
10930                E : constant Entity_Id := Entity (N);
10931             begin
10932                if Present (E) then
10933                   if Is_Generic_Type (E) then
10934                      return Abandon;
10935                   elsif Present (Etype (E))
10936                     and then Is_Generic_Type (Etype (E))
10937                   then
10938                      return Abandon;
10939                   end if;
10940                end if;
10941             end;
10942          end if;
10943
10944          return Atree.OK;
10945       end Process;
10946
10947       function Traverse is new Traverse_Func (Process);
10948       --  Traverse tree to look for generic type
10949
10950    begin
10951       if Inside_A_Generic then
10952          return Traverse (N) = Abandon;
10953       else
10954          return False;
10955       end if;
10956    end References_Generic_Formal_Type;
10957
10958    --------------------
10959    -- Remove_Homonym --
10960    --------------------
10961
10962    procedure Remove_Homonym (E : Entity_Id) is
10963       Prev  : Entity_Id := Empty;
10964       H     : Entity_Id;
10965
10966    begin
10967       if E = Current_Entity (E) then
10968          if Present (Homonym (E)) then
10969             Set_Current_Entity (Homonym (E));
10970          else
10971             Set_Name_Entity_Id (Chars (E), Empty);
10972          end if;
10973       else
10974          H := Current_Entity (E);
10975          while Present (H) and then H /= E loop
10976             Prev := H;
10977             H    := Homonym (H);
10978          end loop;
10979
10980          Set_Homonym (Prev, Homonym (E));
10981       end if;
10982    end Remove_Homonym;
10983
10984    ---------------------
10985    -- Rep_To_Pos_Flag --
10986    ---------------------
10987
10988    function Rep_To_Pos_Flag (E : Entity_Id; Loc : Source_Ptr) return Node_Id is
10989    begin
10990       return New_Occurrence_Of
10991                (Boolean_Literals (not Range_Checks_Suppressed (E)), Loc);
10992    end Rep_To_Pos_Flag;
10993
10994    --------------------
10995    -- Require_Entity --
10996    --------------------
10997
10998    procedure Require_Entity (N : Node_Id) is
10999    begin
11000       if Is_Entity_Name (N) and then No (Entity (N)) then
11001          if Total_Errors_Detected /= 0 then
11002             Set_Entity (N, Any_Id);
11003          else
11004             raise Program_Error;
11005          end if;
11006       end if;
11007    end Require_Entity;
11008
11009    ------------------------------
11010    -- Requires_Transient_Scope --
11011    ------------------------------
11012
11013    --  A transient scope is required when variable-sized temporaries are
11014    --  allocated in the primary or secondary stack, or when finalization
11015    --  actions must be generated before the next instruction.
11016
11017    function Requires_Transient_Scope (Id : Entity_Id) return Boolean is
11018       Typ : constant Entity_Id := Underlying_Type (Id);
11019
11020    --  Start of processing for Requires_Transient_Scope
11021
11022    begin
11023       --  This is a private type which is not completed yet. This can only
11024       --  happen in a default expression (of a formal parameter or of a
11025       --  record component). Do not expand transient scope in this case
11026
11027       if No (Typ) then
11028          return False;
11029
11030       --  Do not expand transient scope for non-existent procedure return
11031
11032       elsif Typ = Standard_Void_Type then
11033          return False;
11034
11035       --  Elementary types do not require a transient scope
11036
11037       elsif Is_Elementary_Type (Typ) then
11038          return False;
11039
11040       --  Generally, indefinite subtypes require a transient scope, since the
11041       --  back end cannot generate temporaries, since this is not a valid type
11042       --  for declaring an object. It might be possible to relax this in the
11043       --  future, e.g. by declaring the maximum possible space for the type.
11044
11045       elsif Is_Indefinite_Subtype (Typ) then
11046          return True;
11047
11048       --  Functions returning tagged types may dispatch on result so their
11049       --  returned value is allocated on the secondary stack. Controlled
11050       --  type temporaries need finalization.
11051
11052       elsif Is_Tagged_Type (Typ)
11053         or else Has_Controlled_Component (Typ)
11054       then
11055          return not Is_Value_Type (Typ);
11056
11057       --  Record type
11058
11059       elsif Is_Record_Type (Typ) then
11060          declare
11061             Comp : Entity_Id;
11062          begin
11063             Comp := First_Entity (Typ);
11064             while Present (Comp) loop
11065                if Ekind (Comp) = E_Component
11066                   and then Requires_Transient_Scope (Etype (Comp))
11067                then
11068                   return True;
11069                else
11070                   Next_Entity (Comp);
11071                end if;
11072             end loop;
11073          end;
11074
11075          return False;
11076
11077       --  String literal types never require transient scope
11078
11079       elsif Ekind (Typ) = E_String_Literal_Subtype then
11080          return False;
11081
11082       --  Array type. Note that we already know that this is a constrained
11083       --  array, since unconstrained arrays will fail the indefinite test.
11084
11085       elsif Is_Array_Type (Typ) then
11086
11087          --  If component type requires a transient scope, the array does too
11088
11089          if Requires_Transient_Scope (Component_Type (Typ)) then
11090             return True;
11091
11092          --  Otherwise, we only need a transient scope if the size depends on
11093          --  the value of one or more discriminants.
11094
11095          else
11096             return Size_Depends_On_Discriminant (Typ);
11097          end if;
11098
11099       --  All other cases do not require a transient scope
11100
11101       else
11102          return False;
11103       end if;
11104    end Requires_Transient_Scope;
11105
11106    --------------------------
11107    -- Reset_Analyzed_Flags --
11108    --------------------------
11109
11110    procedure Reset_Analyzed_Flags (N : Node_Id) is
11111
11112       function Clear_Analyzed (N : Node_Id) return Traverse_Result;
11113       --  Function used to reset Analyzed flags in tree. Note that we do
11114       --  not reset Analyzed flags in entities, since there is no need to
11115       --  reanalyze entities, and indeed, it is wrong to do so, since it
11116       --  can result in generating auxiliary stuff more than once.
11117
11118       --------------------
11119       -- Clear_Analyzed --
11120       --------------------
11121
11122       function Clear_Analyzed (N : Node_Id) return Traverse_Result is
11123       begin
11124          if not Has_Extension (N) then
11125             Set_Analyzed (N, False);
11126          end if;
11127
11128          return OK;
11129       end Clear_Analyzed;
11130
11131       procedure Reset_Analyzed is new Traverse_Proc (Clear_Analyzed);
11132
11133    --  Start of processing for Reset_Analyzed_Flags
11134
11135    begin
11136       Reset_Analyzed (N);
11137    end Reset_Analyzed_Flags;
11138
11139    ---------------------------
11140    -- Safe_To_Capture_Value --
11141    ---------------------------
11142
11143    function Safe_To_Capture_Value
11144      (N    : Node_Id;
11145       Ent  : Entity_Id;
11146       Cond : Boolean := False) return Boolean
11147    is
11148    begin
11149       --  The only entities for which we track constant values are variables
11150       --  which are not renamings, constants, out parameters, and in out
11151       --  parameters, so check if we have this case.
11152
11153       --  Note: it may seem odd to track constant values for constants, but in
11154       --  fact this routine is used for other purposes than simply capturing
11155       --  the value. In particular, the setting of Known[_Non]_Null.
11156
11157       if (Ekind (Ent) = E_Variable and then No (Renamed_Object (Ent)))
11158             or else
11159           Ekind (Ent) = E_Constant
11160             or else
11161           Ekind (Ent) = E_Out_Parameter
11162             or else
11163           Ekind (Ent) = E_In_Out_Parameter
11164       then
11165          null;
11166
11167       --  For conditionals, we also allow loop parameters and all formals,
11168       --  including in parameters.
11169
11170       elsif Cond
11171         and then
11172           (Ekind (Ent) = E_Loop_Parameter
11173              or else
11174            Ekind (Ent) = E_In_Parameter)
11175       then
11176          null;
11177
11178       --  For all other cases, not just unsafe, but impossible to capture
11179       --  Current_Value, since the above are the only entities which have
11180       --  Current_Value fields.
11181
11182       else
11183          return False;
11184       end if;
11185
11186       --  Skip if volatile or aliased, since funny things might be going on in
11187       --  these cases which we cannot necessarily track. Also skip any variable
11188       --  for which an address clause is given, or whose address is taken. Also
11189       --  never capture value of library level variables (an attempt to do so
11190       --  can occur in the case of package elaboration code).
11191
11192       if Treat_As_Volatile (Ent)
11193         or else Is_Aliased (Ent)
11194         or else Present (Address_Clause (Ent))
11195         or else Address_Taken (Ent)
11196         or else (Is_Library_Level_Entity (Ent)
11197                    and then Ekind (Ent) = E_Variable)
11198       then
11199          return False;
11200       end if;
11201
11202       --  OK, all above conditions are met. We also require that the scope of
11203       --  the reference be the same as the scope of the entity, not counting
11204       --  packages and blocks and loops.
11205
11206       declare
11207          E_Scope : constant Entity_Id := Scope (Ent);
11208          R_Scope : Entity_Id;
11209
11210       begin
11211          R_Scope := Current_Scope;
11212          while R_Scope /= Standard_Standard loop
11213             exit when R_Scope = E_Scope;
11214
11215             if not Ekind_In (R_Scope, E_Package, E_Block, E_Loop) then
11216                return False;
11217             else
11218                R_Scope := Scope (R_Scope);
11219             end if;
11220          end loop;
11221       end;
11222
11223       --  We also require that the reference does not appear in a context
11224       --  where it is not sure to be executed (i.e. a conditional context
11225       --  or an exception handler). We skip this if Cond is True, since the
11226       --  capturing of values from conditional tests handles this ok.
11227
11228       if Cond then
11229          return True;
11230       end if;
11231
11232       declare
11233          Desc : Node_Id;
11234          P    : Node_Id;
11235
11236       begin
11237          Desc := N;
11238
11239          P := Parent (N);
11240          while Present (P) loop
11241             if         Nkind (P) = N_If_Statement
11242               or else  Nkind (P) = N_Case_Statement
11243               or else (Nkind (P) in N_Short_Circuit
11244                          and then Desc = Right_Opnd (P))
11245               or else (Nkind (P) = N_Conditional_Expression
11246                          and then Desc /= First (Expressions (P)))
11247               or else  Nkind (P) = N_Exception_Handler
11248               or else  Nkind (P) = N_Selective_Accept
11249               or else  Nkind (P) = N_Conditional_Entry_Call
11250               or else  Nkind (P) = N_Timed_Entry_Call
11251               or else  Nkind (P) = N_Asynchronous_Select
11252             then
11253                return False;
11254             else
11255                Desc := P;
11256                P    := Parent (P);
11257             end if;
11258          end loop;
11259       end;
11260
11261       --  OK, looks safe to set value
11262
11263       return True;
11264    end Safe_To_Capture_Value;
11265
11266    ---------------
11267    -- Same_Name --
11268    ---------------
11269
11270    function Same_Name (N1, N2 : Node_Id) return Boolean is
11271       K1 : constant Node_Kind := Nkind (N1);
11272       K2 : constant Node_Kind := Nkind (N2);
11273
11274    begin
11275       if (K1 = N_Identifier or else K1 = N_Defining_Identifier)
11276         and then (K2 = N_Identifier or else K2 = N_Defining_Identifier)
11277       then
11278          return Chars (N1) = Chars (N2);
11279
11280       elsif (K1 = N_Selected_Component or else K1 = N_Expanded_Name)
11281         and then (K2 = N_Selected_Component or else K2 = N_Expanded_Name)
11282       then
11283          return Same_Name (Selector_Name (N1), Selector_Name (N2))
11284            and then Same_Name (Prefix (N1), Prefix (N2));
11285
11286       else
11287          return False;
11288       end if;
11289    end Same_Name;
11290
11291    -----------------
11292    -- Same_Object --
11293    -----------------
11294
11295    function Same_Object (Node1, Node2 : Node_Id) return Boolean is
11296       N1 : constant Node_Id := Original_Node (Node1);
11297       N2 : constant Node_Id := Original_Node (Node2);
11298       --  We do the tests on original nodes, since we are most interested
11299       --  in the original source, not any expansion that got in the way.
11300
11301       K1 : constant Node_Kind := Nkind (N1);
11302       K2 : constant Node_Kind := Nkind (N2);
11303
11304    begin
11305       --  First case, both are entities with same entity
11306
11307       if K1 in N_Has_Entity and then K2 in N_Has_Entity then
11308          declare
11309             EN1 : constant Entity_Id := Entity (N1);
11310             EN2 : constant Entity_Id := Entity (N2);
11311          begin
11312             if Present (EN1) and then Present (EN2)
11313               and then (Ekind_In (EN1, E_Variable, E_Constant)
11314                          or else Is_Formal (EN1))
11315               and then EN1 = EN2
11316             then
11317                return True;
11318             end if;
11319          end;
11320       end if;
11321
11322       --  Second case, selected component with same selector, same record
11323
11324       if K1 = N_Selected_Component
11325         and then K2 = N_Selected_Component
11326         and then Chars (Selector_Name (N1)) = Chars (Selector_Name (N2))
11327       then
11328          return Same_Object (Prefix (N1), Prefix (N2));
11329
11330       --  Third case, indexed component with same subscripts, same array
11331
11332       elsif K1 = N_Indexed_Component
11333         and then K2 = N_Indexed_Component
11334         and then Same_Object (Prefix (N1), Prefix (N2))
11335       then
11336          declare
11337             E1, E2 : Node_Id;
11338          begin
11339             E1 := First (Expressions (N1));
11340             E2 := First (Expressions (N2));
11341             while Present (E1) loop
11342                if not Same_Value (E1, E2) then
11343                   return False;
11344                else
11345                   Next (E1);
11346                   Next (E2);
11347                end if;
11348             end loop;
11349
11350             return True;
11351          end;
11352
11353       --  Fourth case, slice of same array with same bounds
11354
11355       elsif K1 = N_Slice
11356         and then K2 = N_Slice
11357         and then Nkind (Discrete_Range (N1)) = N_Range
11358         and then Nkind (Discrete_Range (N2)) = N_Range
11359         and then Same_Value (Low_Bound (Discrete_Range (N1)),
11360                              Low_Bound (Discrete_Range (N2)))
11361         and then Same_Value (High_Bound (Discrete_Range (N1)),
11362                              High_Bound (Discrete_Range (N2)))
11363       then
11364          return Same_Name (Prefix (N1), Prefix (N2));
11365
11366       --  All other cases, not clearly the same object
11367
11368       else
11369          return False;
11370       end if;
11371    end Same_Object;
11372
11373    ---------------
11374    -- Same_Type --
11375    ---------------
11376
11377    function Same_Type (T1, T2 : Entity_Id) return Boolean is
11378    begin
11379       if T1 = T2 then
11380          return True;
11381
11382       elsif not Is_Constrained (T1)
11383         and then not Is_Constrained (T2)
11384         and then Base_Type (T1) = Base_Type (T2)
11385       then
11386          return True;
11387
11388       --  For now don't bother with case of identical constraints, to be
11389       --  fiddled with later on perhaps (this is only used for optimization
11390       --  purposes, so it is not critical to do a best possible job)
11391
11392       else
11393          return False;
11394       end if;
11395    end Same_Type;
11396
11397    ----------------
11398    -- Same_Value --
11399    ----------------
11400
11401    function Same_Value (Node1, Node2 : Node_Id) return Boolean is
11402    begin
11403       if Compile_Time_Known_Value (Node1)
11404         and then Compile_Time_Known_Value (Node2)
11405         and then Expr_Value (Node1) = Expr_Value (Node2)
11406       then
11407          return True;
11408       elsif Same_Object (Node1, Node2) then
11409          return True;
11410       else
11411          return False;
11412       end if;
11413    end Same_Value;
11414
11415    -----------------
11416    -- Save_Actual --
11417    -----------------
11418
11419    procedure Save_Actual (N : Node_Id;  Writable : Boolean := False) is
11420    begin
11421       if Ada_Version < Ada_2012 then
11422          return;
11423
11424       elsif Is_Entity_Name (N)
11425         or else
11426           Nkind_In (N, N_Indexed_Component, N_Selected_Component, N_Slice)
11427         or else
11428           (Nkind (N) = N_Attribute_Reference
11429             and then Attribute_Name (N) = Name_Access)
11430
11431       then
11432          --  We are only interested in IN OUT parameters of inner calls
11433
11434          if not Writable
11435            or else Nkind (Parent (N)) = N_Function_Call
11436            or else Nkind (Parent (N)) in N_Op
11437          then
11438             Actuals_In_Call.Increment_Last;
11439             Actuals_In_Call.Table (Actuals_In_Call.Last) := (N, Writable);
11440          end if;
11441       end if;
11442    end Save_Actual;
11443
11444    ------------------------
11445    -- Scope_Is_Transient --
11446    ------------------------
11447
11448    function Scope_Is_Transient return Boolean is
11449    begin
11450       return Scope_Stack.Table (Scope_Stack.Last).Is_Transient;
11451    end Scope_Is_Transient;
11452
11453    ------------------
11454    -- Scope_Within --
11455    ------------------
11456
11457    function Scope_Within (Scope1, Scope2 : Entity_Id) return Boolean is
11458       Scop : Entity_Id;
11459
11460    begin
11461       Scop := Scope1;
11462       while Scop /= Standard_Standard loop
11463          Scop := Scope (Scop);
11464
11465          if Scop = Scope2 then
11466             return True;
11467          end if;
11468       end loop;
11469
11470       return False;
11471    end Scope_Within;
11472
11473    --------------------------
11474    -- Scope_Within_Or_Same --
11475    --------------------------
11476
11477    function Scope_Within_Or_Same (Scope1, Scope2 : Entity_Id) return Boolean is
11478       Scop : Entity_Id;
11479
11480    begin
11481       Scop := Scope1;
11482       while Scop /= Standard_Standard loop
11483          if Scop = Scope2 then
11484             return True;
11485          else
11486             Scop := Scope (Scop);
11487          end if;
11488       end loop;
11489
11490       return False;
11491    end Scope_Within_Or_Same;
11492
11493    --------------------
11494    -- Set_Convention --
11495    --------------------
11496
11497    procedure Set_Convention (E : Entity_Id; Val : Snames.Convention_Id) is
11498    begin
11499       Basic_Set_Convention (E, Val);
11500
11501       if Is_Type (E)
11502         and then Is_Access_Subprogram_Type (Base_Type (E))
11503         and then Has_Foreign_Convention (E)
11504       then
11505          Set_Can_Use_Internal_Rep (E, False);
11506       end if;
11507    end Set_Convention;
11508
11509    ------------------------
11510    -- Set_Current_Entity --
11511    ------------------------
11512
11513    --  The given entity is to be set as the currently visible definition
11514    --  of its associated name (i.e. the Node_Id associated with its name).
11515    --  All we have to do is to get the name from the identifier, and
11516    --  then set the associated Node_Id to point to the given entity.
11517
11518    procedure Set_Current_Entity (E : Entity_Id) is
11519    begin
11520       Set_Name_Entity_Id (Chars (E), E);
11521    end Set_Current_Entity;
11522
11523    ---------------------------
11524    -- Set_Debug_Info_Needed --
11525    ---------------------------
11526
11527    procedure Set_Debug_Info_Needed (T : Entity_Id) is
11528
11529       procedure Set_Debug_Info_Needed_If_Not_Set (E : Entity_Id);
11530       pragma Inline (Set_Debug_Info_Needed_If_Not_Set);
11531       --  Used to set debug info in a related node if not set already
11532
11533       --------------------------------------
11534       -- Set_Debug_Info_Needed_If_Not_Set --
11535       --------------------------------------
11536
11537       procedure Set_Debug_Info_Needed_If_Not_Set (E : Entity_Id) is
11538       begin
11539          if Present (E)
11540            and then not Needs_Debug_Info (E)
11541          then
11542             Set_Debug_Info_Needed (E);
11543
11544             --  For a private type, indicate that the full view also needs
11545             --  debug information.
11546
11547             if Is_Type (E)
11548               and then Is_Private_Type (E)
11549               and then Present (Full_View (E))
11550             then
11551                Set_Debug_Info_Needed (Full_View (E));
11552             end if;
11553          end if;
11554       end Set_Debug_Info_Needed_If_Not_Set;
11555
11556    --  Start of processing for Set_Debug_Info_Needed
11557
11558    begin
11559       --  Nothing to do if argument is Empty or has Debug_Info_Off set, which
11560       --  indicates that Debug_Info_Needed is never required for the entity.
11561
11562       if No (T)
11563         or else Debug_Info_Off (T)
11564       then
11565          return;
11566       end if;
11567
11568       --  Set flag in entity itself. Note that we will go through the following
11569       --  circuitry even if the flag is already set on T. That's intentional,
11570       --  it makes sure that the flag will be set in subsidiary entities.
11571
11572       Set_Needs_Debug_Info (T);
11573
11574       --  Set flag on subsidiary entities if not set already
11575
11576       if Is_Object (T) then
11577          Set_Debug_Info_Needed_If_Not_Set (Etype (T));
11578
11579       elsif Is_Type (T) then
11580          Set_Debug_Info_Needed_If_Not_Set (Etype (T));
11581
11582          if Is_Record_Type (T) then
11583             declare
11584                Ent : Entity_Id := First_Entity (T);
11585             begin
11586                while Present (Ent) loop
11587                   Set_Debug_Info_Needed_If_Not_Set (Ent);
11588                   Next_Entity (Ent);
11589                end loop;
11590             end;
11591
11592             --  For a class wide subtype, we also need debug information
11593             --  for the equivalent type.
11594
11595             if Ekind (T) = E_Class_Wide_Subtype then
11596                Set_Debug_Info_Needed_If_Not_Set (Equivalent_Type (T));
11597             end if;
11598
11599          elsif Is_Array_Type (T) then
11600             Set_Debug_Info_Needed_If_Not_Set (Component_Type (T));
11601
11602             declare
11603                Indx : Node_Id := First_Index (T);
11604             begin
11605                while Present (Indx) loop
11606                   Set_Debug_Info_Needed_If_Not_Set (Etype (Indx));
11607                   Indx := Next_Index (Indx);
11608                end loop;
11609             end;
11610
11611             if Is_Packed (T) then
11612                Set_Debug_Info_Needed_If_Not_Set (Packed_Array_Type (T));
11613             end if;
11614
11615          elsif Is_Access_Type (T) then
11616             Set_Debug_Info_Needed_If_Not_Set (Directly_Designated_Type (T));
11617
11618          elsif Is_Private_Type (T) then
11619             Set_Debug_Info_Needed_If_Not_Set (Full_View (T));
11620
11621          elsif Is_Protected_Type (T) then
11622             Set_Debug_Info_Needed_If_Not_Set (Corresponding_Record_Type (T));
11623          end if;
11624       end if;
11625    end Set_Debug_Info_Needed;
11626
11627    ---------------------------------
11628    -- Set_Entity_With_Style_Check --
11629    ---------------------------------
11630
11631    procedure Set_Entity_With_Style_Check (N : Node_Id; Val : Entity_Id) is
11632       Val_Actual : Entity_Id;
11633       Nod        : Node_Id;
11634
11635    begin
11636       Set_Entity (N, Val);
11637
11638       if Style_Check
11639         and then not Suppress_Style_Checks (Val)
11640         and then not In_Instance
11641       then
11642          if Nkind (N) = N_Identifier then
11643             Nod := N;
11644          elsif Nkind (N) = N_Expanded_Name then
11645             Nod := Selector_Name (N);
11646          else
11647             return;
11648          end if;
11649
11650          --  A special situation arises for derived operations, where we want
11651          --  to do the check against the parent (since the Sloc of the derived
11652          --  operation points to the derived type declaration itself).
11653
11654          Val_Actual := Val;
11655          while not Comes_From_Source (Val_Actual)
11656            and then Nkind (Val_Actual) in N_Entity
11657            and then (Ekind (Val_Actual) = E_Enumeration_Literal
11658                       or else Is_Subprogram (Val_Actual)
11659                       or else Is_Generic_Subprogram (Val_Actual))
11660            and then Present (Alias (Val_Actual))
11661          loop
11662             Val_Actual := Alias (Val_Actual);
11663          end loop;
11664
11665          --  Renaming declarations for generic actuals do not come from source,
11666          --  and have a different name from that of the entity they rename, so
11667          --  there is no style check to perform here.
11668
11669          if Chars (Nod) = Chars (Val_Actual) then
11670             Style.Check_Identifier (Nod, Val_Actual);
11671          end if;
11672       end if;
11673
11674       Set_Entity (N, Val);
11675    end Set_Entity_With_Style_Check;
11676
11677    ------------------------
11678    -- Set_Name_Entity_Id --
11679    ------------------------
11680
11681    procedure Set_Name_Entity_Id (Id : Name_Id; Val : Entity_Id) is
11682    begin
11683       Set_Name_Table_Info (Id, Int (Val));
11684    end Set_Name_Entity_Id;
11685
11686    ---------------------
11687    -- Set_Next_Actual --
11688    ---------------------
11689
11690    procedure Set_Next_Actual (Ass1_Id : Node_Id; Ass2_Id : Node_Id) is
11691    begin
11692       if Nkind (Parent (Ass1_Id)) = N_Parameter_Association then
11693          Set_First_Named_Actual (Parent (Ass1_Id), Ass2_Id);
11694       end if;
11695    end Set_Next_Actual;
11696
11697    ----------------------------------
11698    -- Set_Optimize_Alignment_Flags --
11699    ----------------------------------
11700
11701    procedure Set_Optimize_Alignment_Flags (E : Entity_Id) is
11702    begin
11703       if Optimize_Alignment = 'S' then
11704          Set_Optimize_Alignment_Space (E);
11705       elsif Optimize_Alignment = 'T' then
11706          Set_Optimize_Alignment_Time (E);
11707       end if;
11708    end Set_Optimize_Alignment_Flags;
11709
11710    -----------------------
11711    -- Set_Public_Status --
11712    -----------------------
11713
11714    procedure Set_Public_Status (Id : Entity_Id) is
11715       S : constant Entity_Id := Current_Scope;
11716
11717       function Within_HSS_Or_If (E : Entity_Id) return Boolean;
11718       --  Determines if E is defined within handled statement sequence or
11719       --  an if statement, returns True if so, False otherwise.
11720
11721       ----------------------
11722       -- Within_HSS_Or_If --
11723       ----------------------
11724
11725       function Within_HSS_Or_If (E : Entity_Id) return Boolean is
11726          N : Node_Id;
11727       begin
11728          N := Declaration_Node (E);
11729          loop
11730             N := Parent (N);
11731
11732             if No (N) then
11733                return False;
11734
11735             elsif Nkind_In (N, N_Handled_Sequence_Of_Statements,
11736                                N_If_Statement)
11737             then
11738                return True;
11739             end if;
11740          end loop;
11741       end Within_HSS_Or_If;
11742
11743    --  Start of processing for Set_Public_Status
11744
11745    begin
11746       --  Everything in the scope of Standard is public
11747
11748       if S = Standard_Standard then
11749          Set_Is_Public (Id);
11750
11751       --  Entity is definitely not public if enclosing scope is not public
11752
11753       elsif not Is_Public (S) then
11754          return;
11755
11756       --  An object or function declaration that occurs in a handled sequence
11757       --  of statements or within an if statement is the declaration for a
11758       --  temporary object or local subprogram generated by the expander. It
11759       --  never needs to be made public and furthermore, making it public can
11760       --  cause back end problems.
11761
11762       elsif Nkind_In (Parent (Id), N_Object_Declaration,
11763                                    N_Function_Specification)
11764         and then Within_HSS_Or_If (Id)
11765       then
11766          return;
11767
11768       --  Entities in public packages or records are public
11769
11770       elsif Ekind (S) = E_Package or Is_Record_Type (S) then
11771          Set_Is_Public (Id);
11772
11773       --  The bounds of an entry family declaration can generate object
11774       --  declarations that are visible to the back-end, e.g. in the
11775       --  the declaration of a composite type that contains tasks.
11776
11777       elsif Is_Concurrent_Type (S)
11778         and then not Has_Completion (S)
11779         and then Nkind (Parent (Id)) = N_Object_Declaration
11780       then
11781          Set_Is_Public (Id);
11782       end if;
11783    end Set_Public_Status;
11784
11785    -----------------------------
11786    -- Set_Referenced_Modified --
11787    -----------------------------
11788
11789    procedure Set_Referenced_Modified (N : Node_Id; Out_Param : Boolean) is
11790       Pref : Node_Id;
11791
11792    begin
11793       --  Deal with indexed or selected component where prefix is modified
11794
11795       if Nkind_In (N, N_Indexed_Component, N_Selected_Component) then
11796          Pref := Prefix (N);
11797
11798          --  If prefix is access type, then it is the designated object that is
11799          --  being modified, which means we have no entity to set the flag on.
11800
11801          if No (Etype (Pref)) or else Is_Access_Type (Etype (Pref)) then
11802             return;
11803
11804             --  Otherwise chase the prefix
11805
11806          else
11807             Set_Referenced_Modified (Pref, Out_Param);
11808          end if;
11809
11810       --  Otherwise see if we have an entity name (only other case to process)
11811
11812       elsif Is_Entity_Name (N) and then Present (Entity (N)) then
11813          Set_Referenced_As_LHS           (Entity (N), not Out_Param);
11814          Set_Referenced_As_Out_Parameter (Entity (N), Out_Param);
11815       end if;
11816    end Set_Referenced_Modified;
11817
11818    ----------------------------
11819    -- Set_Scope_Is_Transient --
11820    ----------------------------
11821
11822    procedure Set_Scope_Is_Transient (V : Boolean := True) is
11823    begin
11824       Scope_Stack.Table (Scope_Stack.Last).Is_Transient := V;
11825    end Set_Scope_Is_Transient;
11826
11827    -------------------
11828    -- Set_Size_Info --
11829    -------------------
11830
11831    procedure Set_Size_Info (T1, T2 : Entity_Id) is
11832    begin
11833       --  We copy Esize, but not RM_Size, since in general RM_Size is
11834       --  subtype specific and does not get inherited by all subtypes.
11835
11836       Set_Esize                     (T1, Esize                     (T2));
11837       Set_Has_Biased_Representation (T1, Has_Biased_Representation (T2));
11838
11839       if Is_Discrete_Or_Fixed_Point_Type (T1)
11840            and then
11841          Is_Discrete_Or_Fixed_Point_Type (T2)
11842       then
11843          Set_Is_Unsigned_Type       (T1, Is_Unsigned_Type          (T2));
11844       end if;
11845
11846       Set_Alignment                 (T1, Alignment                 (T2));
11847    end Set_Size_Info;
11848
11849    --------------------
11850    -- Static_Boolean --
11851    --------------------
11852
11853    function Static_Boolean (N : Node_Id) return Uint is
11854    begin
11855       Analyze_And_Resolve (N, Standard_Boolean);
11856
11857       if N = Error
11858         or else Error_Posted (N)
11859         or else Etype (N) = Any_Type
11860       then
11861          return No_Uint;
11862       end if;
11863
11864       if Is_Static_Expression (N) then
11865          if not Raises_Constraint_Error (N) then
11866             return Expr_Value (N);
11867          else
11868             return No_Uint;
11869          end if;
11870
11871       elsif Etype (N) = Any_Type then
11872          return No_Uint;
11873
11874       else
11875          Flag_Non_Static_Expr
11876            ("static boolean expression required here", N);
11877          return No_Uint;
11878       end if;
11879    end Static_Boolean;
11880
11881    --------------------
11882    -- Static_Integer --
11883    --------------------
11884
11885    function Static_Integer (N : Node_Id) return Uint is
11886    begin
11887       Analyze_And_Resolve (N, Any_Integer);
11888
11889       if N = Error
11890         or else Error_Posted (N)
11891         or else Etype (N) = Any_Type
11892       then
11893          return No_Uint;
11894       end if;
11895
11896       if Is_Static_Expression (N) then
11897          if not Raises_Constraint_Error (N) then
11898             return Expr_Value (N);
11899          else
11900             return No_Uint;
11901          end if;
11902
11903       elsif Etype (N) = Any_Type then
11904          return No_Uint;
11905
11906       else
11907          Flag_Non_Static_Expr
11908            ("static integer expression required here", N);
11909          return No_Uint;
11910       end if;
11911    end Static_Integer;
11912
11913    --------------------------
11914    -- Statically_Different --
11915    --------------------------
11916
11917    function Statically_Different (E1, E2 : Node_Id) return Boolean is
11918       R1 : constant Node_Id := Get_Referenced_Object (E1);
11919       R2 : constant Node_Id := Get_Referenced_Object (E2);
11920    begin
11921       return     Is_Entity_Name (R1)
11922         and then Is_Entity_Name (R2)
11923         and then Entity (R1) /= Entity (R2)
11924         and then not Is_Formal (Entity (R1))
11925         and then not Is_Formal (Entity (R2));
11926    end Statically_Different;
11927
11928    -----------------------------
11929    -- Subprogram_Access_Level --
11930    -----------------------------
11931
11932    function Subprogram_Access_Level (Subp : Entity_Id) return Uint is
11933    begin
11934       if Present (Alias (Subp)) then
11935          return Subprogram_Access_Level (Alias (Subp));
11936       else
11937          return Scope_Depth (Enclosing_Dynamic_Scope (Subp));
11938       end if;
11939    end Subprogram_Access_Level;
11940
11941    -----------------
11942    -- Trace_Scope --
11943    -----------------
11944
11945    procedure Trace_Scope (N : Node_Id; E : Entity_Id; Msg : String) is
11946    begin
11947       if Debug_Flag_W then
11948          for J in 0 .. Scope_Stack.Last loop
11949             Write_Str ("  ");
11950          end loop;
11951
11952          Write_Str (Msg);
11953          Write_Name (Chars (E));
11954          Write_Str (" from ");
11955          Write_Location (Sloc (N));
11956          Write_Eol;
11957       end if;
11958    end Trace_Scope;
11959
11960    -----------------------
11961    -- Transfer_Entities --
11962    -----------------------
11963
11964    procedure Transfer_Entities (From : Entity_Id; To : Entity_Id) is
11965       Ent : Entity_Id := First_Entity (From);
11966
11967    begin
11968       if No (Ent) then
11969          return;
11970       end if;
11971
11972       if (Last_Entity (To)) = Empty then
11973          Set_First_Entity (To, Ent);
11974       else
11975          Set_Next_Entity (Last_Entity (To), Ent);
11976       end if;
11977
11978       Set_Last_Entity (To, Last_Entity (From));
11979
11980       while Present (Ent) loop
11981          Set_Scope (Ent, To);
11982
11983          if not Is_Public (Ent) then
11984             Set_Public_Status (Ent);
11985
11986             if Is_Public (Ent)
11987               and then Ekind (Ent) = E_Record_Subtype
11988
11989             then
11990                --  The components of the propagated Itype must be public
11991                --  as well.
11992
11993                declare
11994                   Comp : Entity_Id;
11995                begin
11996                   Comp := First_Entity (Ent);
11997                   while Present (Comp) loop
11998                      Set_Is_Public (Comp);
11999                      Next_Entity (Comp);
12000                   end loop;
12001                end;
12002             end if;
12003          end if;
12004
12005          Next_Entity (Ent);
12006       end loop;
12007
12008       Set_First_Entity (From, Empty);
12009       Set_Last_Entity (From, Empty);
12010    end Transfer_Entities;
12011
12012    -----------------------
12013    -- Type_Access_Level --
12014    -----------------------
12015
12016    function Type_Access_Level (Typ : Entity_Id) return Uint is
12017       Btyp : Entity_Id;
12018
12019    begin
12020       Btyp := Base_Type (Typ);
12021
12022       --  Ada 2005 (AI-230): For most cases of anonymous access types, we
12023       --  simply use the level where the type is declared. This is true for
12024       --  stand-alone object declarations, and for anonymous access types
12025       --  associated with components the level is the same as that of the
12026       --  enclosing composite type. However, special treatment is needed for
12027       --  the cases of access parameters, return objects of an anonymous access
12028       --  type, and, in Ada 95, access discriminants of limited types.
12029
12030       if Ekind (Btyp) in Access_Kind then
12031          if Ekind (Btyp) = E_Anonymous_Access_Type then
12032
12033             --  If the type is a nonlocal anonymous access type (such as for
12034             --  an access parameter) we treat it as being declared at the
12035             --  library level to ensure that names such as X.all'access don't
12036             --  fail static accessibility checks.
12037
12038             if not Is_Local_Anonymous_Access (Typ) then
12039                return Scope_Depth (Standard_Standard);
12040
12041             --  If this is a return object, the accessibility level is that of
12042             --  the result subtype of the enclosing function. The test here is
12043             --  little complicated, because we have to account for extended
12044             --  return statements that have been rewritten as blocks, in which
12045             --  case we have to find and the Is_Return_Object attribute of the
12046             --  itype's associated object. It would be nice to find a way to
12047             --  simplify this test, but it doesn't seem worthwhile to add a new
12048             --  flag just for purposes of this test. ???
12049
12050             elsif Ekind (Scope (Btyp)) = E_Return_Statement
12051               or else
12052                 (Is_Itype (Btyp)
12053                   and then Nkind (Associated_Node_For_Itype (Btyp)) =
12054                              N_Object_Declaration
12055                   and then Is_Return_Object
12056                              (Defining_Identifier
12057                                 (Associated_Node_For_Itype (Btyp))))
12058             then
12059                declare
12060                   Scop : Entity_Id;
12061
12062                begin
12063                   Scop := Scope (Scope (Btyp));
12064                   while Present (Scop) loop
12065                      exit when Ekind (Scop) = E_Function;
12066                      Scop := Scope (Scop);
12067                   end loop;
12068
12069                   --  Treat the return object's type as having the level of the
12070                   --  function's result subtype (as per RM05-6.5(5.3/2)).
12071
12072                   return Type_Access_Level (Etype (Scop));
12073                end;
12074             end if;
12075          end if;
12076
12077          Btyp := Root_Type (Btyp);
12078
12079          --  The accessibility level of anonymous access types associated with
12080          --  discriminants is that of the current instance of the type, and
12081          --  that's deeper than the type itself (AARM 3.10.2 (12.3.21)).
12082
12083          --  AI-402: access discriminants have accessibility based on the
12084          --  object rather than the type in Ada 2005, so the above paragraph
12085          --  doesn't apply.
12086
12087          --  ??? Needs completion with rules from AI-416
12088
12089          if Ada_Version <= Ada_95
12090            and then Ekind (Typ) = E_Anonymous_Access_Type
12091            and then Present (Associated_Node_For_Itype (Typ))
12092            and then Nkind (Associated_Node_For_Itype (Typ)) =
12093                                                  N_Discriminant_Specification
12094          then
12095             return Scope_Depth (Enclosing_Dynamic_Scope (Btyp)) + 1;
12096          end if;
12097       end if;
12098
12099       return Scope_Depth (Enclosing_Dynamic_Scope (Btyp));
12100    end Type_Access_Level;
12101
12102    --------------------------
12103    -- Unit_Declaration_Node --
12104    --------------------------
12105
12106    function Unit_Declaration_Node (Unit_Id : Entity_Id) return Node_Id is
12107       N : Node_Id := Parent (Unit_Id);
12108
12109    begin
12110       --  Predefined operators do not have a full function declaration
12111
12112       if Ekind (Unit_Id) = E_Operator then
12113          return N;
12114       end if;
12115
12116       --  Isn't there some better way to express the following ???
12117
12118       while Nkind (N) /= N_Abstract_Subprogram_Declaration
12119         and then Nkind (N) /= N_Formal_Package_Declaration
12120         and then Nkind (N) /= N_Function_Instantiation
12121         and then Nkind (N) /= N_Generic_Package_Declaration
12122         and then Nkind (N) /= N_Generic_Subprogram_Declaration
12123         and then Nkind (N) /= N_Package_Declaration
12124         and then Nkind (N) /= N_Package_Body
12125         and then Nkind (N) /= N_Package_Instantiation
12126         and then Nkind (N) /= N_Package_Renaming_Declaration
12127         and then Nkind (N) /= N_Procedure_Instantiation
12128         and then Nkind (N) /= N_Protected_Body
12129         and then Nkind (N) /= N_Subprogram_Declaration
12130         and then Nkind (N) /= N_Subprogram_Body
12131         and then Nkind (N) /= N_Subprogram_Body_Stub
12132         and then Nkind (N) /= N_Subprogram_Renaming_Declaration
12133         and then Nkind (N) /= N_Task_Body
12134         and then Nkind (N) /= N_Task_Type_Declaration
12135         and then Nkind (N) not in N_Formal_Subprogram_Declaration
12136         and then Nkind (N) not in N_Generic_Renaming_Declaration
12137       loop
12138          N := Parent (N);
12139          pragma Assert (Present (N));
12140       end loop;
12141
12142       return N;
12143    end Unit_Declaration_Node;
12144
12145    ---------------------
12146    -- Unit_Is_Visible --
12147    ---------------------
12148
12149    function Unit_Is_Visible (U : Entity_Id) return Boolean is
12150       Curr        : constant Node_Id   := Cunit (Current_Sem_Unit);
12151       Curr_Entity : constant Entity_Id := Cunit_Entity (Current_Sem_Unit);
12152
12153       function Unit_In_Parent_Context (Par_Unit : Node_Id) return Boolean;
12154       --  For a child unit, check whether unit appears in a with_clause
12155       --  of a parent.
12156
12157       function Unit_In_Context (Comp_Unit : Node_Id) return Boolean;
12158       --  Scan the context clause of one compilation unit looking for a
12159       --  with_clause for the unit in question.
12160
12161       ----------------------------
12162       -- Unit_In_Parent_Context --
12163       ----------------------------
12164
12165       function Unit_In_Parent_Context (Par_Unit : Node_Id) return Boolean is
12166       begin
12167          if Unit_In_Context (Par_Unit) then
12168             return True;
12169
12170          elsif Is_Child_Unit (Defining_Entity (Unit (Par_Unit))) then
12171             return Unit_In_Parent_Context (Parent_Spec (Unit (Par_Unit)));
12172
12173          else
12174             return False;
12175          end if;
12176       end Unit_In_Parent_Context;
12177
12178       ---------------------
12179       -- Unit_In_Context --
12180       ---------------------
12181
12182       function Unit_In_Context (Comp_Unit : Node_Id) return Boolean is
12183          Clause : Node_Id;
12184
12185       begin
12186          Clause := First (Context_Items (Comp_Unit));
12187          while Present (Clause) loop
12188             if Nkind (Clause) = N_With_Clause then
12189                if Library_Unit (Clause) = U then
12190                   return True;
12191
12192                --  The with_clause may denote a renaming of the unit we are
12193                --  looking for, eg. Text_IO which renames Ada.Text_IO.
12194
12195                elsif
12196                  Renamed_Entity (Entity (Name (Clause))) =
12197                                                 Defining_Entity (Unit (U))
12198                then
12199                   return True;
12200                end if;
12201             end if;
12202
12203             Next (Clause);
12204          end loop;
12205
12206          return False;
12207       end Unit_In_Context;
12208
12209    --  Start of processing for Unit_Is_Visible
12210
12211    begin
12212       --  The currrent unit is directly visible.
12213
12214       if Curr = U then
12215          return True;
12216
12217       elsif Unit_In_Context (Curr) then
12218          return True;
12219
12220       --  If the current unit is a body, check the context of the spec.
12221
12222       elsif Nkind (Unit (Curr)) = N_Package_Body
12223         or else
12224           (Nkind (Unit (Curr)) = N_Subprogram_Body
12225             and then not Acts_As_Spec (Unit (Curr)))
12226       then
12227          if Unit_In_Context (Library_Unit (Curr)) then
12228             return True;
12229          end if;
12230       end if;
12231
12232       --  If the spec is a child unit, examine the parents.
12233
12234       if Is_Child_Unit (Curr_Entity) then
12235          if Nkind (Unit (Curr)) in N_Unit_Body then
12236             return
12237               Unit_In_Parent_Context
12238                 (Parent_Spec (Unit (Library_Unit (Curr))));
12239          else
12240             return Unit_In_Parent_Context (Parent_Spec (Unit (Curr)));
12241          end if;
12242
12243       else
12244          return False;
12245       end if;
12246    end Unit_Is_Visible;
12247
12248    ------------------------------
12249    -- Universal_Interpretation --
12250    ------------------------------
12251
12252    function Universal_Interpretation (Opnd : Node_Id) return Entity_Id is
12253       Index : Interp_Index;
12254       It    : Interp;
12255
12256    begin
12257       --  The argument may be a formal parameter of an operator or subprogram
12258       --  with multiple interpretations, or else an expression for an actual.
12259
12260       if Nkind (Opnd) = N_Defining_Identifier
12261         or else not Is_Overloaded (Opnd)
12262       then
12263          if Etype (Opnd) = Universal_Integer
12264            or else Etype (Opnd) = Universal_Real
12265          then
12266             return Etype (Opnd);
12267          else
12268             return Empty;
12269          end if;
12270
12271       else
12272          Get_First_Interp (Opnd, Index, It);
12273          while Present (It.Typ) loop
12274             if It.Typ = Universal_Integer
12275               or else It.Typ = Universal_Real
12276             then
12277                return It.Typ;
12278             end if;
12279
12280             Get_Next_Interp (Index, It);
12281          end loop;
12282
12283          return Empty;
12284       end if;
12285    end Universal_Interpretation;
12286
12287    ---------------
12288    -- Unqualify --
12289    ---------------
12290
12291    function Unqualify (Expr : Node_Id) return Node_Id is
12292    begin
12293       --  Recurse to handle unlikely case of multiple levels of qualification
12294
12295       if Nkind (Expr) = N_Qualified_Expression then
12296          return Unqualify (Expression (Expr));
12297
12298       --  Normal case, not a qualified expression
12299
12300       else
12301          return Expr;
12302       end if;
12303    end Unqualify;
12304
12305    -----------------------
12306    -- Visible_Ancestors --
12307    -----------------------
12308
12309    function Visible_Ancestors (Typ : Entity_Id) return Elist_Id is
12310       List_1 : Elist_Id;
12311       List_2 : Elist_Id;
12312       Elmt   : Elmt_Id;
12313
12314    begin
12315       pragma Assert (Is_Record_Type (Typ)
12316         and then Is_Tagged_Type (Typ));
12317
12318       --  Collect all the parents and progenitors of Typ. If the full-view of
12319       --  private parents and progenitors is available then it is used to
12320       --  generate the list of visible ancestors; otherwise their partial
12321       --  view is added to the resulting list.
12322
12323       Collect_Parents
12324         (T               => Typ,
12325          List            => List_1,
12326          Use_Full_View   => True);
12327
12328       Collect_Interfaces
12329         (T               => Typ,
12330          Ifaces_List     => List_2,
12331          Exclude_Parents => True,
12332          Use_Full_View   => True);
12333
12334       --  Join the two lists. Avoid duplications because an interface may
12335       --  simultaneously be parent and progenitor of a type.
12336
12337       Elmt := First_Elmt (List_2);
12338       while Present (Elmt) loop
12339          Append_Unique_Elmt (Node (Elmt), List_1);
12340          Next_Elmt (Elmt);
12341       end loop;
12342
12343       return List_1;
12344    end Visible_Ancestors;
12345
12346    ----------------------
12347    -- Within_Init_Proc --
12348    ----------------------
12349
12350    function Within_Init_Proc return Boolean is
12351       S : Entity_Id;
12352
12353    begin
12354       S := Current_Scope;
12355       while not Is_Overloadable (S) loop
12356          if S = Standard_Standard then
12357             return False;
12358          else
12359             S := Scope (S);
12360          end if;
12361       end loop;
12362
12363       return Is_Init_Proc (S);
12364    end Within_Init_Proc;
12365
12366    ----------------
12367    -- Wrong_Type --
12368    ----------------
12369
12370    procedure Wrong_Type (Expr : Node_Id; Expected_Type : Entity_Id) is
12371       Found_Type : constant Entity_Id := First_Subtype (Etype (Expr));
12372       Expec_Type : constant Entity_Id := First_Subtype (Expected_Type);
12373
12374       function Has_One_Matching_Field return Boolean;
12375       --  Determines if Expec_Type is a record type with a single component or
12376       --  discriminant whose type matches the found type or is one dimensional
12377       --  array whose component type matches the found type.
12378
12379       ----------------------------
12380       -- Has_One_Matching_Field --
12381       ----------------------------
12382
12383       function Has_One_Matching_Field return Boolean is
12384          E : Entity_Id;
12385
12386       begin
12387          if Is_Array_Type (Expec_Type)
12388            and then Number_Dimensions (Expec_Type) = 1
12389            and then
12390              Covers (Etype (Component_Type (Expec_Type)), Found_Type)
12391          then
12392             return True;
12393
12394          elsif not Is_Record_Type (Expec_Type) then
12395             return False;
12396
12397          else
12398             E := First_Entity (Expec_Type);
12399             loop
12400                if No (E) then
12401                   return False;
12402
12403                elsif (Ekind (E) /= E_Discriminant
12404                        and then Ekind (E) /= E_Component)
12405                  or else (Chars (E) = Name_uTag
12406                            or else Chars (E) = Name_uParent)
12407                then
12408                   Next_Entity (E);
12409
12410                else
12411                   exit;
12412                end if;
12413             end loop;
12414
12415             if not Covers (Etype (E), Found_Type) then
12416                return False;
12417
12418             elsif Present (Next_Entity (E)) then
12419                return False;
12420
12421             else
12422                return True;
12423             end if;
12424          end if;
12425       end Has_One_Matching_Field;
12426
12427    --  Start of processing for Wrong_Type
12428
12429    begin
12430       --  Don't output message if either type is Any_Type, or if a message
12431       --  has already been posted for this node. We need to do the latter
12432       --  check explicitly (it is ordinarily done in Errout), because we
12433       --  are using ! to force the output of the error messages.
12434
12435       if Expec_Type = Any_Type
12436         or else Found_Type = Any_Type
12437         or else Error_Posted (Expr)
12438       then
12439          return;
12440
12441       --  In  an instance, there is an ongoing problem with completion of
12442       --  type derived from private types. Their structure is what Gigi
12443       --  expects, but the  Etype is the parent type rather than the
12444       --  derived private type itself. Do not flag error in this case. The
12445       --  private completion is an entity without a parent, like an Itype.
12446       --  Similarly, full and partial views may be incorrect in the instance.
12447       --  There is no simple way to insure that it is consistent ???
12448
12449       elsif In_Instance then
12450          if Etype (Etype (Expr)) = Etype (Expected_Type)
12451            and then
12452              (Has_Private_Declaration (Expected_Type)
12453                or else Has_Private_Declaration (Etype (Expr)))
12454            and then No (Parent (Expected_Type))
12455          then
12456             return;
12457          end if;
12458       end if;
12459
12460       --  An interesting special check. If the expression is parenthesized
12461       --  and its type corresponds to the type of the sole component of the
12462       --  expected record type, or to the component type of the expected one
12463       --  dimensional array type, then assume we have a bad aggregate attempt.
12464
12465       if Nkind (Expr) in N_Subexpr
12466         and then Paren_Count (Expr) /= 0
12467         and then Has_One_Matching_Field
12468       then
12469          Error_Msg_N ("positional aggregate cannot have one component", Expr);
12470
12471       --  Another special check, if we are looking for a pool-specific access
12472       --  type and we found an E_Access_Attribute_Type, then we have the case
12473       --  of an Access attribute being used in a context which needs a pool-
12474       --  specific type, which is never allowed. The one extra check we make
12475       --  is that the expected designated type covers the Found_Type.
12476
12477       elsif Is_Access_Type (Expec_Type)
12478         and then Ekind (Found_Type) = E_Access_Attribute_Type
12479         and then Ekind (Base_Type (Expec_Type)) /= E_General_Access_Type
12480         and then Ekind (Base_Type (Expec_Type)) /= E_Anonymous_Access_Type
12481         and then Covers
12482           (Designated_Type (Expec_Type), Designated_Type (Found_Type))
12483       then
12484          Error_Msg_N -- CODEFIX
12485            ("result must be general access type!", Expr);
12486          Error_Msg_NE -- CODEFIX
12487            ("add ALL to }!", Expr, Expec_Type);
12488
12489       --  Another special check, if the expected type is an integer type,
12490       --  but the expression is of type System.Address, and the parent is
12491       --  an addition or subtraction operation whose left operand is the
12492       --  expression in question and whose right operand is of an integral
12493       --  type, then this is an attempt at address arithmetic, so give
12494       --  appropriate message.
12495
12496       elsif Is_Integer_Type (Expec_Type)
12497         and then Is_RTE (Found_Type, RE_Address)
12498         and then (Nkind (Parent (Expr)) = N_Op_Add
12499                     or else
12500                   Nkind (Parent (Expr)) = N_Op_Subtract)
12501         and then Expr = Left_Opnd (Parent (Expr))
12502         and then Is_Integer_Type (Etype (Right_Opnd (Parent (Expr))))
12503       then
12504          Error_Msg_N
12505            ("address arithmetic not predefined in package System",
12506             Parent (Expr));
12507          Error_Msg_N
12508            ("\possible missing with/use of System.Storage_Elements",
12509             Parent (Expr));
12510          return;
12511
12512       --  If the expected type is an anonymous access type, as for access
12513       --  parameters and discriminants, the error is on the designated types.
12514
12515       elsif Ekind (Expec_Type) = E_Anonymous_Access_Type then
12516          if Comes_From_Source (Expec_Type) then
12517             Error_Msg_NE ("expected}!", Expr, Expec_Type);
12518          else
12519             Error_Msg_NE
12520               ("expected an access type with designated}",
12521                  Expr, Designated_Type (Expec_Type));
12522          end if;
12523
12524          if Is_Access_Type (Found_Type)
12525            and then not Comes_From_Source (Found_Type)
12526          then
12527             Error_Msg_NE
12528               ("\\found an access type with designated}!",
12529                 Expr, Designated_Type (Found_Type));
12530          else
12531             if From_With_Type (Found_Type) then
12532                Error_Msg_NE ("\\found incomplete}!", Expr, Found_Type);
12533                Error_Msg_Qual_Level := 99;
12534                Error_Msg_NE -- CODEFIX
12535                  ("\\missing `WITH &;", Expr, Scope (Found_Type));
12536                Error_Msg_Qual_Level := 0;
12537             else
12538                Error_Msg_NE ("found}!", Expr, Found_Type);
12539             end if;
12540          end if;
12541
12542       --  Normal case of one type found, some other type expected
12543
12544       else
12545          --  If the names of the two types are the same, see if some number
12546          --  of levels of qualification will help. Don't try more than three
12547          --  levels, and if we get to standard, it's no use (and probably
12548          --  represents an error in the compiler) Also do not bother with
12549          --  internal scope names.
12550
12551          declare
12552             Expec_Scope : Entity_Id;
12553             Found_Scope : Entity_Id;
12554
12555          begin
12556             Expec_Scope := Expec_Type;
12557             Found_Scope := Found_Type;
12558
12559             for Levels in Int range 0 .. 3 loop
12560                if Chars (Expec_Scope) /= Chars (Found_Scope) then
12561                   Error_Msg_Qual_Level := Levels;
12562                   exit;
12563                end if;
12564
12565                Expec_Scope := Scope (Expec_Scope);
12566                Found_Scope := Scope (Found_Scope);
12567
12568                exit when Expec_Scope = Standard_Standard
12569                  or else Found_Scope = Standard_Standard
12570                  or else not Comes_From_Source (Expec_Scope)
12571                  or else not Comes_From_Source (Found_Scope);
12572             end loop;
12573          end;
12574
12575          if Is_Record_Type (Expec_Type)
12576            and then Present (Corresponding_Remote_Type (Expec_Type))
12577          then
12578             Error_Msg_NE ("expected}!", Expr,
12579                           Corresponding_Remote_Type (Expec_Type));
12580          else
12581             Error_Msg_NE ("expected}!", Expr, Expec_Type);
12582          end if;
12583
12584          if Is_Entity_Name (Expr)
12585            and then Is_Package_Or_Generic_Package (Entity (Expr))
12586          then
12587             Error_Msg_N ("\\found package name!", Expr);
12588
12589          elsif Is_Entity_Name (Expr)
12590            and then
12591              (Ekind (Entity (Expr)) = E_Procedure
12592                 or else
12593               Ekind (Entity (Expr)) = E_Generic_Procedure)
12594          then
12595             if Ekind (Expec_Type) = E_Access_Subprogram_Type then
12596                Error_Msg_N
12597                  ("found procedure name, possibly missing Access attribute!",
12598                    Expr);
12599             else
12600                Error_Msg_N
12601                  ("\\found procedure name instead of function!", Expr);
12602             end if;
12603
12604          elsif Nkind (Expr) = N_Function_Call
12605            and then Ekind (Expec_Type) = E_Access_Subprogram_Type
12606            and then Etype (Designated_Type (Expec_Type)) = Etype (Expr)
12607            and then No (Parameter_Associations (Expr))
12608          then
12609             Error_Msg_N
12610               ("found function name, possibly missing Access attribute!",
12611                Expr);
12612
12613          --  Catch common error: a prefix or infix operator which is not
12614          --  directly visible because the type isn't.
12615
12616          elsif Nkind (Expr) in N_Op
12617             and then Is_Overloaded (Expr)
12618             and then not Is_Immediately_Visible (Expec_Type)
12619             and then not Is_Potentially_Use_Visible (Expec_Type)
12620             and then not In_Use (Expec_Type)
12621             and then Has_Compatible_Type (Right_Opnd (Expr), Expec_Type)
12622          then
12623             Error_Msg_N
12624               ("operator of the type is not directly visible!", Expr);
12625
12626          elsif Ekind (Found_Type) = E_Void
12627            and then Present (Parent (Found_Type))
12628            and then Nkind (Parent (Found_Type)) = N_Full_Type_Declaration
12629          then
12630             Error_Msg_NE ("\\found premature usage of}!", Expr, Found_Type);
12631
12632          else
12633             Error_Msg_NE ("\\found}!", Expr, Found_Type);
12634          end if;
12635
12636          --  A special check for cases like M1 and M2 = 0 where M1 and M2 are
12637          --  of the same modular type, and (M1 and M2) = 0 was intended.
12638
12639          if Expec_Type = Standard_Boolean
12640            and then Is_Modular_Integer_Type (Found_Type)
12641            and then Nkind_In (Parent (Expr), N_Op_And, N_Op_Or, N_Op_Xor)
12642            and then Nkind (Right_Opnd (Parent (Expr))) in N_Op_Compare
12643          then
12644             declare
12645                Op : constant Node_Id := Right_Opnd (Parent (Expr));
12646                L  : constant Node_Id := Left_Opnd (Op);
12647                R  : constant Node_Id := Right_Opnd (Op);
12648             begin
12649                --  The case for the message is when the left operand of the
12650                --  comparison is the same modular type, or when it is an
12651                --  integer literal (or other universal integer expression),
12652                --  which would have been typed as the modular type if the
12653                --  parens had been there.
12654
12655                if (Etype (L) = Found_Type
12656                      or else
12657                    Etype (L) = Universal_Integer)
12658                  and then Is_Integer_Type (Etype (R))
12659                then
12660                   Error_Msg_N
12661                     ("\\possible missing parens for modular operation", Expr);
12662                end if;
12663             end;
12664          end if;
12665
12666          --  Reset error message qualification indication
12667
12668          Error_Msg_Qual_Level := 0;
12669       end if;
12670    end Wrong_Type;
12671
12672 end Sem_Util;