gcc/ada/exp_imgv.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             E X P _ I M G V                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2001-2003 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 2,  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 COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- GNAT was originally developed  by the GNAT team at  New York University. --
  23 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  24 --                                                                          --
  25 ------------------------------------------------------------------------------
  26
  27 with Atree;    use Atree;
  28 with Casing;   use Casing;
  29 with Checks;   use Checks;
  30 with Einfo;    use Einfo;
  31 with Exp_Util; use Exp_Util;
  32 with Namet;    use Namet;
  33 with Nmake;    use Nmake;
  34 with Nlists;   use Nlists;
  35 with Opt;      use Opt;
  36 with Rtsfind;  use Rtsfind;
  37 with Sem_Res;  use Sem_Res;
  38 with Sinfo;    use Sinfo;
  39 with Snames;   use Snames;
  40 with Stand;    use Stand;
  41 with Stringt;  use Stringt;
  42 with Tbuild;   use Tbuild;
  43 with Ttypes;   use Ttypes;
  44 with Uintp;    use Uintp;
  45
  46 package body Exp_Imgv is
  47
  48    ------------------------------------
  49    -- Build_Enumeration_Image_Tables --
  50    ------------------------------------
  51
  52    procedure Build_Enumeration_Image_Tables (E : Entity_Id; N : Node_Id) is
  53       Loc  : constant Source_Ptr := Sloc (E);
  54       Str  : String_Id;
  55       Ind  : List_Id;
  56       Lit  : Entity_Id;
  57       Nlit : Nat;
  58       Len  : Nat;
  59       Estr : Entity_Id;
  60       Eind : Entity_Id;
  61       Ityp : Node_Id;
  62
  63    begin
  64       --  Nothing to do for other than a root enumeration type
  65
  66       if E /= Root_Type (E) then
  67          return;
  68
  69       --  Nothing to do if pragma Discard_Names applies
  70
  71       elsif Discard_Names (E) then
  72          return;
  73       end if;
  74
  75       --  Otherwise tables need constructing
  76
  77       Start_String;
  78       Ind := New_List;
  79       Lit := First_Literal (E);
  80       Len := 1;
  81       Nlit := 0;
  82
  83       loop
  84          Append_To (Ind,
  85            Make_Integer_Literal (Loc, UI_From_Int (Len)));
  86
  87          exit when No (Lit);
  88          Nlit := Nlit + 1;
  89
  90          Get_Unqualified_Decoded_Name_String (Chars (Lit));
  91
  92          if Name_Buffer (1) /= ''' then
  93             Set_Casing (All_Upper_Case);
  94          end if;
  95
  96          Store_String_Chars (Name_Buffer (1 .. Name_Len));
  97          Len := Len + Int (Name_Len);
  98          Next_Literal (Lit);
  99       end loop;
 100
 101       if Len < Int (2 ** (8 - 1)) then
 102          Ityp := Standard_Integer_8;
 103       elsif Len < Int (2 ** (16 - 1)) then
 104          Ityp := Standard_Integer_16;
 105       else
 106          Ityp := Standard_Integer_32;
 107       end if;
 108
 109       Str := End_String;
 110
 111       Estr :=
 112         Make_Defining_Identifier (Loc,
 113           Chars => New_External_Name (Chars (E), 'S'));
 114
 115       Eind :=
 116         Make_Defining_Identifier (Loc,
 117           Chars => New_External_Name (Chars (E), 'N'));
 118
 119       Set_Lit_Strings (E, Estr);
 120       Set_Lit_Indexes (E, Eind);
 121
 122       Insert_Actions (N,
 123         New_List (
 124           Make_Object_Declaration (Loc,
 125             Defining_Identifier => Estr,
 126             Constant_Present    => True,
 127             Object_Definition   =>
 128               New_Occurrence_Of (Standard_String, Loc),
 129             Expression          =>
 130               Make_String_Literal (Loc,
 131                 Strval => Str)),
 132
 133           Make_Object_Declaration (Loc,
 134             Defining_Identifier => Eind,
 135             Constant_Present    => True,
 136
 137             Object_Definition =>
 138               Make_Constrained_Array_Definition (Loc,
 139                 Discrete_Subtype_Definitions => New_List (
 140                   Make_Range (Loc,
 141                     Low_Bound  => Make_Integer_Literal (Loc, 0),
 142                     High_Bound => Make_Integer_Literal (Loc, Nlit))),
 143                 Subtype_Indication => New_Occurrence_Of (Ityp, Loc)),
 144
 145             Expression          =>
 146               Make_Aggregate (Loc,
 147                 Expressions => Ind))),
 148         Suppress => All_Checks);
 149
 150    end Build_Enumeration_Image_Tables;
 151
 152    ----------------------------
 153    -- Expand_Image_Attribute --
 154    ----------------------------
 155
 156    --  For all non-enumeration types, and for enumeration types declared
 157    --  in packages Standard or System, typ'Image (Val) expands into:
 158
 159    --     Image_xx (tp (Expr) [, pm])
 160
 161    --  The name xx and type conversion tp (Expr) (called tv below) depend on
 162    --  the root type of Expr. The argument pm is an extra type dependent
 163    --  parameter only used in some cases as follows:
 164
 165    --    For types whose root type is Character
 166    --      xx = Character
 167    --      tv = Character (Expr)
 168
 169    --    For types whose root type is Boolean
 170    --      xx = Boolean
 171    --      tv = Boolean (Expr)
 172
 173    --    For signed integer types with size <= Integer'Size
 174    --      xx = Integer
 175    --      tv = Integer (Expr)
 176
 177    --    For other signed integer types
 178    --      xx = Long_Long_Integer
 179    --      tv = Long_Long_Integer (Expr)
 180
 181    --    For modular types with modulus <= System.Unsigned_Types.Unsigned
 182    --      xx = Unsigned
 183    --      tv = System.Unsigned_Types.Unsigned (Expr)
 184
 185    --    For other modular integer types
 186    --      xx = Long_Long_Unsigned
 187    --      tv = System.Unsigned_Types.Long_Long_Unsigned (Expr)
 188
 189    --    For types whose root type is Wide_Character
 190    --      xx = Wide_Character
 191    --      tv = Wide_Character (Expr)
 192    --      pm = Wide_Character_Encoding_Method
 193
 194    --    For floating-point types
 195    --      xx = Floating_Point
 196    --      tv = Long_Long_Float (Expr)
 197    --      pm = typ'Digits
 198
 199    --    For ordinary fixed-point types
 200    --      xx = Ordinary_Fixed_Point
 201    --      tv = Long_Long_Float (Expr)
 202    --      pm = typ'Aft
 203
 204    --    For decimal fixed-point types with size = Integer'Size
 205    --      xx = Decimal
 206    --      tv = Integer (Expr)
 207    --      pm = typ'Scale
 208
 209    --    For decimal fixed-point types with size > Integer'Size
 210    --      xx = Long_Long_Decimal
 211    --      tv = Long_Long_Integer (Expr)
 212    --      pm = typ'Scale
 213
 214    --    Note: for the decimal fixed-point type cases, the conversion is
 215    --    done literally without scaling (i.e. the actual expression that
 216    --    is generated is Image_xx (tp?(Expr) [, pm])
 217
 218    --  For enumeration types other than those declared packages Standard
 219    --  or System, typ'Image (X) expands into:
 220
 221    --    Image_Enumeration_NN (typ'Pos (X), typS, typI'Address)
 222
 223    --  where typS and typI are the entities constructed as described in
 224    --  the spec for the procedure Build_Enumeration_Image_Tables and NN
 225    --  is 32/16/8 depending on the element type of Lit_Indexes.
 226
 227    procedure Expand_Image_Attribute (N : Node_Id) is
 228       Loc      : constant Source_Ptr := Sloc (N);
 229       Exprs    : constant List_Id    := Expressions (N);
 230       Pref     : constant Node_Id    := Prefix (N);
 231       Ptyp     : constant Entity_Id  := Entity (Pref);
 232       Rtyp     : constant Entity_Id  := Root_Type (Ptyp);
 233       Expr     : constant Node_Id    := Relocate_Node (First (Exprs));
 234       Imid     : RE_Id;
 235       Tent     : Entity_Id;
 236       Arglist  : List_Id;
 237       Func     : RE_Id;
 238       Ttyp     : Entity_Id;
 239       Func_Ent : Entity_Id;
 240
 241    begin
 242       if Rtyp = Standard_Boolean then
 243          Imid := RE_Image_Boolean;
 244          Tent := Rtyp;
 245
 246       elsif Rtyp = Standard_Character then
 247          Imid := RE_Image_Character;
 248          Tent := Rtyp;
 249
 250       elsif Rtyp = Standard_Wide_Character then
 251          Imid := RE_Image_Wide_Character;
 252          Tent := Rtyp;
 253
 254       elsif Is_Signed_Integer_Type (Rtyp) then
 255          if Esize (Rtyp) <= Esize (Standard_Integer) then
 256             Imid := RE_Image_Integer;
 257             Tent := Standard_Integer;
 258          else
 259             Imid := RE_Image_Long_Long_Integer;
 260             Tent := Standard_Long_Long_Integer;
 261          end if;
 262
 263       elsif Is_Modular_Integer_Type (Rtyp) then
 264          if Modulus (Rtyp) <= Modulus (RTE (RE_Unsigned)) then
 265             Imid := RE_Image_Unsigned;
 266             Tent := RTE (RE_Unsigned);
 267          else
 268             Imid := RE_Image_Long_Long_Unsigned;
 269             Tent := RTE (RE_Long_Long_Unsigned);
 270          end if;
 271
 272       elsif Is_Decimal_Fixed_Point_Type (Rtyp) then
 273          if UI_To_Int (Esize (Rtyp)) <= Standard_Integer_Size then
 274             Imid := RE_Image_Decimal;
 275             Tent := Standard_Integer;
 276          else
 277             Imid := RE_Image_Long_Long_Decimal;
 278             Tent := Standard_Long_Long_Integer;
 279          end if;
 280
 281       elsif Is_Ordinary_Fixed_Point_Type (Rtyp) then
 282          Imid := RE_Image_Ordinary_Fixed_Point;
 283          Tent := Standard_Long_Long_Float;
 284
 285       elsif Is_Floating_Point_Type (Rtyp) then
 286          Imid := RE_Image_Floating_Point;
 287          Tent := Standard_Long_Long_Float;
 288
 289       --  Only other possibility is user defined enumeration type
 290
 291       else
 292          if Discard_Names (First_Subtype (Ptyp))
 293            or else No (Lit_Strings (Root_Type (Ptyp)))
 294          then
 295             --  When pragma Discard_Names applies to the first subtype,
 296             --  then build (Pref'Pos)'Img.
 297
 298             Rewrite (N,
 299               Make_Attribute_Reference (Loc,
 300                 Prefix =>
 301                    Make_Attribute_Reference (Loc,
 302                      Prefix         => Pref,
 303                      Attribute_Name => Name_Pos,
 304                      Expressions    => New_List (Expr)),
 305                 Attribute_Name =>
 306                   Name_Img));
 307             Analyze_And_Resolve (N, Standard_String);
 308
 309          else
 310             --  Here we get the Image of an enumeration type
 311
 312             Ttyp := Component_Type (Etype (Lit_Indexes (Rtyp)));
 313
 314             if Ttyp = Standard_Integer_8 then
 315                Func := RE_Image_Enumeration_8;
 316             elsif Ttyp = Standard_Integer_16  then
 317                Func := RE_Image_Enumeration_16;
 318             else
 319                Func := RE_Image_Enumeration_32;
 320             end if;
 321
 322             --  Apply a validity check, since it is a bit drastic to
 323             --  get a completely junk image value for an invalid value.
 324
 325             if not Expr_Known_Valid (Expr) then
 326                Insert_Valid_Check (Expr);
 327             end if;
 328
 329             Rewrite (N,
 330               Make_Function_Call (Loc,
 331                 Name => New_Occurrence_Of (RTE (Func), Loc),
 332                 Parameter_Associations => New_List (
 333                   Make_Attribute_Reference (Loc,
 334                     Attribute_Name => Name_Pos,
 335                     Prefix         => New_Occurrence_Of (Ptyp, Loc),
 336                     Expressions    => New_List (Expr)),
 337                   New_Occurrence_Of (Lit_Strings (Rtyp), Loc),
 338                   Make_Attribute_Reference (Loc,
 339                     Prefix => New_Occurrence_Of (Lit_Indexes (Rtyp), Loc),
 340                     Attribute_Name => Name_Address))));
 341
 342             Analyze_And_Resolve (N, Standard_String);
 343          end if;
 344
 345          return;
 346       end if;
 347
 348       --  If we fall through, we have one of the cases that is handled by
 349       --  calling one of the System.Img_xx routines and Imid is set to the
 350       --  RE_Id for the function to be called.
 351
 352       Func_Ent := RTE (Imid);
 353
 354       --  If the function entity is empty, that means we have a case in
 355       --  no run time mode where the operation is not allowed, and an
 356       --  appropriate diagnostic has already been issued.
 357
 358       if No (Func_Ent) then
 359          return;
 360       end if;
 361
 362       --  Otherwise prepare arguments for run-time call
 363
 364       Arglist := New_List (Convert_To (Tent, Relocate_Node (Expr)));
 365
 366       --  For floating-point types, append Digits argument
 367
 368       if Is_Floating_Point_Type (Rtyp) then
 369          Append_To (Arglist,
 370            Make_Attribute_Reference (Loc,
 371              Prefix         => New_Reference_To (Ptyp, Loc),
 372              Attribute_Name => Name_Digits));
 373
 374       --  For ordinary fixed-point types, append Aft parameter
 375
 376       elsif Is_Ordinary_Fixed_Point_Type (Rtyp) then
 377          Append_To (Arglist,
 378            Make_Attribute_Reference (Loc,
 379              Prefix         => New_Reference_To (Ptyp, Loc),
 380              Attribute_Name => Name_Aft));
 381
 382       --  For wide character, append encoding method
 383
 384       elsif Rtyp = Standard_Wide_Character then
 385          Append_To (Arglist,
 386            Make_Integer_Literal (Loc,
 387              Intval => Int (Wide_Character_Encoding_Method)));
 388
 389       --  For decimal, append Scale and also set to do literal conversion
 390
 391       elsif Is_Decimal_Fixed_Point_Type (Rtyp) then
 392          Append_To (Arglist,
 393            Make_Attribute_Reference (Loc,
 394              Prefix => New_Reference_To (Ptyp, Loc),
 395              Attribute_Name => Name_Scale));
 396
 397          Set_Conversion_OK (First (Arglist));
 398          Set_Etype (First (Arglist), Tent);
 399       end if;
 400
 401       Rewrite (N,
 402         Make_Function_Call (Loc,
 403           Name => New_Reference_To (Func_Ent, Loc),
 404           Parameter_Associations => Arglist));
 405
 406       Analyze_And_Resolve (N, Standard_String);
 407    end Expand_Image_Attribute;
 408
 409    ----------------------------
 410    -- Expand_Value_Attribute --
 411    ----------------------------
 412
 413    --  For scalar types derived from Boolean, Character and integer types
 414    --  in package Standard, typ'Value (X) expands into:
 415
 416    --    btyp (Value_xx (X))
 417
 418    --  where btyp is he base type of the prefix, and
 419
 420    --    For types whose root type is Character
 421    --      xx = Character
 422
 423    --    For types whose root type is Boolean
 424    --      xx = Boolean
 425
 426    --    For signed integer types with size <= Integer'Size
 427    --      xx = Integer
 428
 429    --    For other signed integer types
 430    --      xx = Long_Long_Integer
 431
 432    --    For modular types with modulus <= System.Unsigned_Types.Unsigned
 433    --      xx = Unsigned
 434
 435    --    For other modular integer types
 436    --      xx = Long_Long_Unsigned
 437
 438    --    For floating-point types and ordinary fixed-point types
 439    --      xx = Real
 440
 441    --  For types derived from Wide_Character, typ'Value (X) expands into
 442
 443    --    Value_Wide_Character (X, Wide_Character_Encoding_Method)
 444
 445    --  For decimal types with size <= Integer'Size, typ'Value (X)
 446    --  expands into
 447
 448    --    btyp?(Value_Decimal (X, typ'Scale));
 449
 450    --  For all other decimal types, typ'Value (X) expands into
 451
 452    --    btyp?(Value_Long_Long_Decimal (X, typ'Scale))
 453
 454    --  For enumeration types other than those derived from types Boolean,
 455    --  Character, and Wide_Character in Standard, typ'Value (X) expands to:
 456
 457    --    Enum'Val (Value_Enumeration_NN (typS, typI'Address, Num, X))
 458
 459    --  where typS and typI and the Lit_Strings and Lit_Indexes entities
 460    --  from T's root type entitym and Num is Enum'Pos (Enum'Last). The
 461    --  Value_Enumeration_NN function will search the tables looking for
 462    --  X and return the position number in the table if found which is
 463    --  used to provide the result of 'Value (using Enum'Val). If the
 464    --  value is not found Constraint_Error is raised. The suffix _NN
 465    --  depends on the element type of typI.
 466
 467    procedure Expand_Value_Attribute (N : Node_Id) is
 468       Loc   : constant Source_Ptr := Sloc (N);
 469       Typ   : constant Entity_Id  := Etype (N);
 470       Btyp  : constant Entity_Id  := Base_Type (Typ);
 471       Rtyp  : constant Entity_Id  := Root_Type (Typ);
 472       Exprs : constant List_Id    := Expressions (N);
 473       Vid   : RE_Id;
 474       Args  : List_Id;
 475       Func  : RE_Id;
 476       Ttyp  : Entity_Id;
 477
 478    begin
 479       Args := Exprs;
 480
 481       if Rtyp = Standard_Character then
 482          Vid := RE_Value_Character;
 483
 484       elsif Rtyp = Standard_Boolean then
 485          Vid := RE_Value_Boolean;
 486
 487       elsif Rtyp = Standard_Wide_Character then
 488          Vid := RE_Value_Wide_Character;
 489          Append_To (Args,
 490            Make_Integer_Literal (Loc,
 491              Intval => Int (Wide_Character_Encoding_Method)));
 492
 493       elsif     Rtyp = Base_Type (Standard_Short_Short_Integer)
 494         or else Rtyp = Base_Type (Standard_Short_Integer)
 495         or else Rtyp = Base_Type (Standard_Integer)
 496       then
 497          Vid := RE_Value_Integer;
 498
 499       elsif Is_Signed_Integer_Type (Rtyp) then
 500          Vid := RE_Value_Long_Long_Integer;
 501
 502       elsif Is_Modular_Integer_Type (Rtyp) then
 503          if Modulus (Rtyp) <= Modulus (RTE (RE_Unsigned)) then
 504             Vid := RE_Value_Unsigned;
 505          else
 506             Vid := RE_Value_Long_Long_Unsigned;
 507          end if;
 508
 509       elsif Is_Decimal_Fixed_Point_Type (Rtyp) then
 510          if UI_To_Int (Esize (Rtyp)) <= Standard_Integer_Size then
 511             Vid := RE_Value_Decimal;
 512          else
 513             Vid := RE_Value_Long_Long_Decimal;
 514          end if;
 515
 516          Append_To (Args,
 517            Make_Attribute_Reference (Loc,
 518              Prefix => New_Reference_To (Typ, Loc),
 519              Attribute_Name => Name_Scale));
 520
 521          Rewrite (N,
 522            OK_Convert_To (Btyp,
 523              Make_Function_Call (Loc,
 524                Name => New_Reference_To (RTE (Vid), Loc),
 525                Parameter_Associations => Args)));
 526
 527          Set_Etype (N, Btyp);
 528          Analyze_And_Resolve (N, Btyp);
 529          return;
 530
 531       elsif Is_Real_Type (Rtyp) then
 532          Vid := RE_Value_Real;
 533
 534       --  Only other possibility is user defined enumeration type
 535
 536       else
 537          pragma Assert (Is_Enumeration_Type (Rtyp));
 538
 539          --  Case of pragma Discard_Names, transform the Value
 540          --  attribute to Btyp'Val (Long_Long_Integer'Value (Args))
 541
 542          if Discard_Names (First_Subtype (Typ))
 543            or else No (Lit_Strings (Rtyp))
 544          then
 545             Rewrite (N,
 546               Make_Attribute_Reference (Loc,
 547                 Prefix => New_Reference_To (Btyp, Loc),
 548                 Attribute_Name => Name_Val,
 549                 Expressions => New_List (
 550                   Make_Attribute_Reference (Loc,
 551                     Prefix =>
 552                       New_Occurrence_Of (Standard_Long_Long_Integer, Loc),
 553                     Attribute_Name => Name_Value,
 554                     Expressions => Args))));
 555
 556             Analyze_And_Resolve (N, Btyp);
 557
 558          --  Here for normal case where we have enumeration tables, this
 559          --  is where we build
 560
 561          --    T'Val (Value_Enumeration_NN (typS, typI'Address, Num, X))
 562
 563          else
 564             Ttyp := Component_Type (Etype (Lit_Indexes (Rtyp)));
 565
 566             if Ttyp = Standard_Integer_8 then
 567                Func := RE_Value_Enumeration_8;
 568             elsif Ttyp = Standard_Integer_16  then
 569                Func := RE_Value_Enumeration_16;
 570             else
 571                Func := RE_Value_Enumeration_32;
 572             end if;
 573
 574             Prepend_To (Args,
 575               Make_Attribute_Reference (Loc,
 576                 Prefix => New_Occurrence_Of (Rtyp, Loc),
 577                 Attribute_Name => Name_Pos,
 578                 Expressions => New_List (
 579                   Make_Attribute_Reference (Loc,
 580                     Prefix => New_Occurrence_Of (Rtyp, Loc),
 581                     Attribute_Name => Name_Last))));
 582
 583             Prepend_To (Args,
 584               Make_Attribute_Reference (Loc,
 585                 Prefix => New_Occurrence_Of (Lit_Indexes (Rtyp), Loc),
 586                 Attribute_Name => Name_Address));
 587
 588             Prepend_To (Args,
 589               New_Occurrence_Of (Lit_Strings (Rtyp), Loc));
 590
 591             Rewrite (N,
 592               Make_Attribute_Reference (Loc,
 593                 Prefix => New_Reference_To (Typ, Loc),
 594                 Attribute_Name => Name_Val,
 595                 Expressions => New_List (
 596                   Make_Function_Call (Loc,
 597                     Name =>
 598                       New_Reference_To (RTE (Func), Loc),
 599                     Parameter_Associations => Args))));
 600
 601             Analyze_And_Resolve (N, Btyp);
 602          end if;
 603
 604          return;
 605       end if;
 606
 607       --  Fall through for all cases except user defined enumeration type
 608       --  and decimal types, with Vid set to the Id of the entity for the
 609       --  Value routine and Args set to the list of parameters for the call.
 610
 611       Rewrite (N,
 612         Convert_To (Btyp,
 613           Make_Function_Call (Loc,
 614             Name => New_Reference_To (RTE (Vid), Loc),
 615             Parameter_Associations => Args)));
 616
 617       Analyze_And_Resolve (N, Btyp);
 618    end Expand_Value_Attribute;
 619
 620    ----------------------------
 621    -- Expand_Width_Attribute --
 622    ----------------------------
 623
 624    --  The processing here also handles the case of Wide_Width. With the
 625    --  exceptions noted, the processing is identical
 626
 627    --  For scalar types derived from Boolean, character and integer types
 628    --  in package Standard. Note that the Width attribute is computed at
 629    --  compile time for all cases except those involving non-static sub-
 630    --  types. For such subtypes, typ'Width and typ'Wide_Width expands into:
 631
 632    --    Result_Type (xx (yy (Ptyp'First), yy (Ptyp'Last)))
 633
 634    --  where
 635
 636    --    For types whose root type is Character
 637    --      xx = Width_Character (Wide_Width_Character for Wide_Width case)
 638    --      yy = Character
 639
 640    --    For types whose root type is Boolean
 641    --      xx = Width_Boolean
 642    --      yy = Boolean
 643
 644    --    For signed integer types
 645    --      xx = Width_Long_Long_Integer
 646    --      yy = Long_Long_Integer
 647
 648    --    For modular integer types
 649    --      xx = Width_Long_Long_Unsigned
 650    --      yy = Long_Long_Unsigned
 651
 652    --  For types derived from Wide_Character, typ'Width expands into
 653
 654    --    Result_Type (Width_Wide_Character (
 655    --      Wide_Character (typ'First),
 656    --      Wide_Character (typ'Last),
 657    --      Wide_Character_Encoding_Method);
 658
 659    --  and typ'Wide_Width expands into:
 660
 661    --    Result_Type (Wide_Width_Wide_Character (
 662    --      Wide_Character (typ'First),
 663    --      Wide_Character (typ'Last));
 664
 665    --  For real types, typ'Width and typ'Wide_Width expand into
 666
 667    --    if Ptyp'First > Ptyp'Last then 0 else btyp'Width end if
 668
 669    --  where btyp is the base type. This looks recursive but it isn't
 670    --  because the base type is always static, and hence the expression
 671    --  in the else is reduced to an integer literal.
 672
 673    --  For user defined enumeration types, typ'Width expands into
 674
 675    --    Result_Type (Width_Enumeration_NN
 676    --                  (typS,
 677    --                   typI'Address,
 678    --                   typ'Pos (typ'First),
 679    --                   typ'Pos (Typ'Last)));
 680
 681    --  and typ'Wide_Width expands into:
 682
 683    --    Result_Type (Wide_Width_Enumeration_NN
 684    --                  (typS,
 685    --                   typI,
 686    --                   typ'Pos (typ'First),
 687    --                   typ'Pos (Typ'Last))
 688    --                   Wide_Character_Encoding_Method);
 689
 690    --  where typS and typI are the enumeration image strings and
 691    --  indexes table, as described in Build_Enumeration_Image_Tables.
 692    --  NN is 8/16/32 for depending on the element type for typI.
 693
 694    procedure Expand_Width_Attribute (N : Node_Id; Wide : Boolean) is
 695       Loc     : constant Source_Ptr := Sloc (N);
 696       Typ     : constant Entity_Id  := Etype (N);
 697       Pref    : constant Node_Id    := Prefix (N);
 698       Ptyp    : constant Entity_Id  := Etype (Pref);
 699       Rtyp    : constant Entity_Id  := Root_Type (Ptyp);
 700       XX      : RE_Id;
 701       YY      : Entity_Id;
 702       Arglist : List_Id;
 703       Ttyp    : Entity_Id;
 704
 705    begin
 706       --  Types derived from Standard.Boolean
 707
 708       if Rtyp = Standard_Boolean then
 709          XX := RE_Width_Boolean;
 710          YY := Rtyp;
 711
 712       --  Types derived from Standard.Character
 713
 714       elsif Rtyp = Standard_Character then
 715          if not Wide then
 716             XX := RE_Width_Character;
 717          else
 718             XX := RE_Wide_Width_Character;
 719          end if;
 720
 721          YY := Rtyp;
 722
 723       --  Types derived from Standard.Wide_Character
 724
 725       elsif Rtyp = Standard_Wide_Character then
 726          if not Wide then
 727             XX := RE_Width_Wide_Character;
 728          else
 729             XX := RE_Wide_Width_Wide_Character;
 730          end if;
 731
 732          YY := Rtyp;
 733
 734       --  Signed integer types
 735
 736       elsif Is_Signed_Integer_Type (Rtyp) then
 737          XX := RE_Width_Long_Long_Integer;
 738          YY := Standard_Long_Long_Integer;
 739
 740       --  Modular integer types
 741
 742       elsif Is_Modular_Integer_Type (Rtyp) then
 743          XX := RE_Width_Long_Long_Unsigned;
 744          YY := RTE (RE_Long_Long_Unsigned);
 745
 746       --  Real types
 747
 748       elsif Is_Real_Type (Rtyp) then
 749
 750          Rewrite (N,
 751            Make_Conditional_Expression (Loc,
 752              Expressions => New_List (
 753
 754                Make_Op_Gt (Loc,
 755                  Left_Opnd =>
 756                    Make_Attribute_Reference (Loc,
 757                      Prefix => New_Reference_To (Ptyp, Loc),
 758                      Attribute_Name => Name_First),
 759
 760                  Right_Opnd =>
 761                    Make_Attribute_Reference (Loc,
 762                      Prefix => New_Reference_To (Ptyp, Loc),
 763                      Attribute_Name => Name_Last)),
 764
 765                Make_Integer_Literal (Loc, 0),
 766
 767                Make_Attribute_Reference (Loc,
 768                  Prefix => New_Reference_To (Base_Type (Ptyp), Loc),
 769                  Attribute_Name => Name_Width))));
 770
 771          Analyze_And_Resolve (N, Typ);
 772          return;
 773
 774       --  User defined enumeration types
 775
 776       else
 777          pragma Assert (Is_Enumeration_Type (Rtyp));
 778
 779          Ttyp := Component_Type (Etype (Lit_Indexes (Rtyp)));
 780
 781          if not Wide then
 782             if Ttyp = Standard_Integer_8 then
 783                XX := RE_Width_Enumeration_8;
 784             elsif Ttyp = Standard_Integer_16  then
 785                XX := RE_Width_Enumeration_16;
 786             else
 787                XX := RE_Width_Enumeration_32;
 788             end if;
 789
 790          else
 791             if Ttyp = Standard_Integer_8 then
 792                XX := RE_Wide_Width_Enumeration_8;
 793             elsif Ttyp = Standard_Integer_16  then
 794                XX := RE_Wide_Width_Enumeration_16;
 795             else
 796                XX := RE_Wide_Width_Enumeration_32;
 797             end if;
 798          end if;
 799
 800          Arglist :=
 801            New_List (
 802              New_Occurrence_Of (Lit_Strings (Rtyp), Loc),
 803
 804              Make_Attribute_Reference (Loc,
 805                Prefix => New_Occurrence_Of (Lit_Indexes (Rtyp), Loc),
 806                Attribute_Name => Name_Address),
 807
 808              Make_Attribute_Reference (Loc,
 809                Prefix => New_Reference_To (Ptyp, Loc),
 810                Attribute_Name => Name_Pos,
 811
 812                Expressions => New_List (
 813                  Make_Attribute_Reference (Loc,
 814                    Prefix => New_Reference_To (Ptyp, Loc),
 815                    Attribute_Name => Name_First))),
 816
 817              Make_Attribute_Reference (Loc,
 818                Prefix => New_Reference_To (Ptyp, Loc),
 819                Attribute_Name => Name_Pos,
 820
 821                Expressions => New_List (
 822                  Make_Attribute_Reference (Loc,
 823                    Prefix => New_Reference_To (Ptyp, Loc),
 824                    Attribute_Name => Name_Last))));
 825
 826          --  For enumeration'Wide_Width, add encoding method parameter
 827
 828          if Wide then
 829             Append_To (Arglist,
 830               Make_Integer_Literal (Loc,
 831                 Intval => Int (Wide_Character_Encoding_Method)));
 832          end if;
 833
 834          Rewrite (N,
 835            Convert_To (Typ,
 836              Make_Function_Call (Loc,
 837                Name => New_Reference_To (RTE (XX), Loc),
 838                Parameter_Associations => Arglist)));
 839
 840          Analyze_And_Resolve (N, Typ);
 841          return;
 842       end if;
 843
 844       --  If we fall through XX and YY are set
 845
 846       Arglist := New_List (
 847         Convert_To (YY,
 848           Make_Attribute_Reference (Loc,
 849             Prefix => New_Reference_To (Ptyp, Loc),
 850             Attribute_Name => Name_First)),
 851
 852         Convert_To (YY,
 853           Make_Attribute_Reference (Loc,
 854             Prefix => New_Reference_To (Ptyp, Loc),
 855             Attribute_Name => Name_Last)));
 856
 857       --  For Wide_Character'Width, add encoding method parameter
 858
 859       if Rtyp = Standard_Wide_Character and then Wide then
 860          Append_To (Arglist,
 861            Make_Integer_Literal (Loc,
 862              Intval => Int (Wide_Character_Encoding_Method)));
 863       end if;
 864
 865       Rewrite (N,
 866         Convert_To (Typ,
 867           Make_Function_Call (Loc,
 868             Name => New_Reference_To (RTE (XX), Loc),
 869             Parameter_Associations => Arglist)));
 870
 871       Analyze_And_Resolve (N, Typ);
 872    end Expand_Width_Attribute;
 873
 874 end Exp_Imgv;