mcs/mcs/cfold.cs

   1 //
   2 // cfold.cs: Constant Folding
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2002, 2003 Ximian, Inc.
   8 //
   9
  10 using System;
  11
  12 namespace Mono.CSharp {
  13
  14         public class ConstantFold {
  15
  16                 //
  17                 // Performs the numeric promotions on the left and right expresions
  18                 // and desposits the results on `lc' and `rc'.
  19                 //
  20                 // On success, the types of `lc' and `rc' on output will always match,
  21                 // and the pair will be one of:
  22                 //
  23                 //   (double, double)
  24                 //   (float, float)
  25                 //   (ulong, ulong)
  26                 //   (long, long)
  27                 //   (uint, uint)
  28                 //   (int, int)
  29                 //   (short, short)   (Happens with enumerations with underlying short type)
  30                 //   (ushort, ushort) (Happens with enumerations with underlying short type)
  31                 //
  32                 static void DoConstantNumericPromotions (EmitContext ec, Binary.Operator oper,
  33                                                          ref Constant left, ref Constant right,
  34                                                          Location loc)
  35                 {
  36                         if (left is DoubleConstant || right is DoubleConstant){
  37                                 //
  38                                 // If either side is a double, convert the other to a double
  39                                 //
  40                                 if (!(left is DoubleConstant))
  41                                         left = left.ToDouble (loc);
  42
  43                                 if (!(right is DoubleConstant))
  44                                         right = right.ToDouble (loc);
  45                                 return;
  46                         } else if (left is FloatConstant || right is FloatConstant) {
  47                                 //
  48                                 // If either side is a float, convert the other to a float
  49                                 //
  50                                 if (!(left is FloatConstant))
  51                                         left = left.ToFloat (loc);
  52
  53                                 if (!(right is FloatConstant))
  54                                         right = right.ToFloat (loc);
  55 ;                               return;
  56                         } else if (left is ULongConstant || right is ULongConstant){
  57                                 //
  58                                 // If either operand is of type ulong, the other operand is
  59                                 // converted to type ulong.  or an error ocurrs if the other
  60                                 // operand is of type sbyte, short, int or long
  61                                 //
  62 #if WRONG
  63                                 Constant match, other;
  64 #endif
  65
  66                                 if (left is ULongConstant){
  67 #if WRONG
  68                                         other = right;
  69                                         match = left;
  70 #endif
  71                                         if (!(right is ULongConstant))
  72                                                 right = right.ToULong (loc);
  73                                 } else {
  74 #if WRONG
  75                                         other = left;
  76                                         match = right;
  77 #endif
  78                                         left = left.ToULong (loc);
  79                                 }
  80
  81 #if WRONG
  82                                 if (other is SByteConstant || other is ShortConstant ||
  83                                     other is IntConstant || other is LongConstant){
  84                                         Binary.Error_OperatorAmbiguous
  85                                                 (loc, oper, other.Type, match.Type);
  86                                         left = null;
  87                                         right = null;
  88                                 }
  89 #endif
  90                                 return;
  91                         } else if (left is LongConstant || right is LongConstant){
  92                                 //
  93                                 // If either operand is of type long, the other operand is converted
  94                                 // to type long.
  95                                 //
  96                                 if (!(left is LongConstant))
  97                                         left = left.ToLong (loc);
  98                                 else if (!(right is LongConstant))
  99                                         right = right.ToLong (loc);
 100                                 return;
 101                         } else if (left is UIntConstant || right is UIntConstant){
 102                                 //
 103                                 // If either operand is of type uint, and the other
 104                                 // operand is of type sbyte, short or int, the operands are
 105                                 // converted to type long.
 106                                 //
 107                                 Constant other;
 108                                 if (left is UIntConstant)
 109                                         other = right;
 110                                 else
 111                                         other = left;
 112
 113                                 // Nothing to do.
 114                                 if (other is UIntConstant)
 115                                         return;
 116
 117                                 IntConstant ic = other as IntConstant;
 118                                 if (ic != null){
 119                                         if (ic.Value >= 0){
 120                                                 if (left == other)
 121                                                         left = new UIntConstant ((uint) ic.Value);
 122                                                 else
 123                                                         right = new UIntConstant ((uint) ic.Value);
 124                                                 return;
 125                                         }
 126                                 }
 127
 128                                 if (other is SByteConstant || other is ShortConstant || ic != null){
 129                                         left = left.ToLong (loc);
 130                                         right = right.ToLong (loc);
 131                                 } else {
 132                                         left = left.ToUInt (loc);
 133                                         right = left.ToUInt (loc);
 134                                 }
 135
 136                                 return;
 137                         } else if (left is DecimalConstant || right is DecimalConstant) {
 138                                 if (!(left is DecimalConstant))
 139                                         left = left.ToDecimal (loc);
 140                                 else if (!(right is DecimalConstant))
 141                                         right = right.ToDecimal (loc);
 142                                 return;
 143                         } else if (left is EnumConstant || right is EnumConstant){
 144                                 //
 145                                 // If either operand is an enum constant, the other one must
 146                                 // be implicitly convertable to that enum's underlying type.
 147                                 //
 148                                 EnumConstant match;
 149                                 Constant other;
 150                                 if (left is EnumConstant){
 151                                         other = right;
 152                                         match = (EnumConstant) left;
 153                                 } else {
 154                                         other = left;
 155                                         match = (EnumConstant) right;
 156                                 }
 157
 158                                 bool need_check = (other is EnumConstant) ||
 159                                         ((oper != Binary.Operator.Addition) &&
 160                                          (oper != Binary.Operator.Subtraction));
 161
 162                                 if (need_check &&
 163                                     !Convert.ImplicitConversionExists (ec, match, other.Type)) {
 164                                         Convert.Error_CannotImplicitConversion (loc, match.Type, other.Type);
 165                                         left = null;
 166                                         right = null;
 167                                         return;
 168                                 }
 169
 170                                 if (left is EnumConstant)
 171                                         left = ((EnumConstant) left).Child;
 172                                 if (right is EnumConstant)
 173                                         right = ((EnumConstant) right).Child;
 174                                 return;
 175
 176                         } else {
 177                                 //
 178                                 // Force conversions to int32
 179                                 //
 180                                 if (!(left is IntConstant))
 181                                         left = left.ToInt (loc);
 182                                 if (!(right is IntConstant))
 183                                         right = right.ToInt (loc);
 184                         }
 185                         return;
 186                 }
 187
 188                 static void Error_CompileTimeOverflow (Location loc)
 189                 {
 190                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 191                 }
 192
 193                 /// <summary>
 194                 ///   Constant expression folder for binary operations.
 195                 ///
 196                 ///   Returns null if the expression can not be folded.
 197                 /// </summary>
 198                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 199                                                      Constant left, Constant right, Location loc)
 200                 {
 201                         Type lt = left.Type;
 202                         Type rt = right.Type;
 203                         Type result_type = null;
 204                         bool bool_res;
 205
 206                         //
 207                         // Enumerator folding
 208                         //
 209                         if (rt == lt && left is EnumConstant)
 210                                 result_type = lt;
 211
 212                         //
 213                         // During an enum evaluation, we need to unwrap enumerations
 214                         //
 215                         if (ec.InEnumContext){
 216                                 if (left is EnumConstant)
 217                                         left = ((EnumConstant) left).Child;
 218
 219                                 if (right is EnumConstant)
 220                                         right = ((EnumConstant) right).Child;
 221                         }
 222
 223                         Type wrap_as;
 224                         Constant result = null;
 225                         switch (oper){
 226                         case Binary.Operator.BitwiseOr:
 227                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 228                                 if (left == null || right == null)
 229                                         return null;
 230
 231                                 if (left is IntConstant){
 232                                         IntConstant v;
 233                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 234
 235                                         v = new IntConstant (res);
 236                                         if (result_type == null)
 237                                                 return v;
 238                                         else
 239                                                 return new EnumConstant (v, result_type);
 240                                 } else if (left is UIntConstant){
 241                                         UIntConstant v;
 242                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 243
 244                                         v = new UIntConstant (res);
 245                                         if (result_type == null)
 246                                                 return v;
 247                                         else
 248                                                 return new EnumConstant (v, result_type);
 249                                 } else if (left is LongConstant){
 250                                         LongConstant v;
 251                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 252
 253                                         v = new LongConstant (res);
 254                                         if (result_type == null)
 255                                                 return v;
 256                                         else
 257                                                 return new EnumConstant (v, result_type);
 258                                 } else if (left is ULongConstant){
 259                                         ULongConstant v;
 260                                         ulong res = ((ULongConstant)left).Value |
 261                                                 ((ULongConstant)right).Value;
 262
 263                                         v = new ULongConstant (res);
 264                                         if (result_type == null)
 265                                                 return v;
 266                                         else
 267                                                 return new EnumConstant (v, result_type);
 268                                 } else if (left is UShortConstant){
 269                                         UShortConstant v;
 270                                         ushort res = (ushort) (((UShortConstant)left).Value |
 271                                                                ((UShortConstant)right).Value);
 272
 273                                         v = new UShortConstant (res);
 274                                         if (result_type == null)
 275                                                 return v;
 276                                         else
 277                                                 return new EnumConstant (v, result_type);
 278                                 } else if (left is ShortConstant){
 279                                         ShortConstant v;
 280                                         short res = (short) (((ShortConstant)left).Value |
 281                                                              ((ShortConstant)right).Value);
 282
 283                                         v = new ShortConstant (res);
 284                                         if (result_type == null)
 285                                                 return v;
 286                                         else
 287                                                 return new EnumConstant (v, result_type);
 288                                 }
 289                                 break;
 290
 291                         case Binary.Operator.BitwiseAnd:
 292                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 293                                 if (left == null || right == null)
 294                                         return null;
 295
 296                                 if (left is IntConstant){
 297                                         IntConstant v;
 298                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 299
 300                                         v = new IntConstant (res);
 301                                         if (result_type == null)
 302                                                 return v;
 303                                         else
 304                                                 return new EnumConstant (v, result_type);
 305                                 } else if (left is UIntConstant){
 306                                         UIntConstant v;
 307                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 308
 309                                         v = new UIntConstant (res);
 310                                         if (result_type == null)
 311                                                 return v;
 312                                         else
 313                                                 return new EnumConstant (v, result_type);
 314                                 } else if (left is LongConstant){
 315                                         LongConstant v;
 316                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 317
 318                                         v = new LongConstant (res);
 319                                         if (result_type == null)
 320                                                 return v;
 321                                         else
 322                                                 return new EnumConstant (v, result_type);
 323                                 } else if (left is ULongConstant){
 324                                         ULongConstant v;
 325                                         ulong res = ((ULongConstant)left).Value &
 326                                                 ((ULongConstant)right).Value;
 327
 328                                         v = new ULongConstant (res);
 329                                         if (result_type == null)
 330                                                 return v;
 331                                         else
 332                                                 return new EnumConstant (v, result_type);
 333                                 } else if (left is UShortConstant){
 334                                         UShortConstant v;
 335                                         ushort res = (ushort) (((UShortConstant)left).Value &
 336                                                                ((UShortConstant)right).Value);
 337
 338                                         v = new UShortConstant (res);
 339                                         if (result_type == null)
 340                                                 return v;
 341                                         else
 342                                                 return new EnumConstant (v, result_type);
 343                                 } else if (left is ShortConstant){
 344                                         ShortConstant v;
 345                                         short res = (short) (((ShortConstant)left).Value &
 346                                                              ((ShortConstant)right).Value);
 347
 348                                         v = new ShortConstant (res);
 349                                         if (result_type == null)
 350                                                 return v;
 351                                         else
 352                                                 return new EnumConstant (v, result_type);
 353                                 }
 354                                 break;
 355
 356                         case Binary.Operator.ExclusiveOr:
 357                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 358                                 if (left == null || right == null)
 359                                         return null;
 360
 361                                 if (left is IntConstant){
 362                                         IntConstant v;
 363                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 364
 365                                         v = new IntConstant (res);
 366                                         if (result_type == null)
 367                                                 return v;
 368                                         else
 369                                                 return new EnumConstant (v, result_type);
 370                                 } else if (left is UIntConstant){
 371                                         UIntConstant v;
 372                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 373
 374                                         v = new UIntConstant (res);
 375                                         if (result_type == null)
 376                                                 return v;
 377                                         else
 378                                                 return new EnumConstant (v, result_type);
 379                                 } else if (left is LongConstant){
 380                                         LongConstant v;
 381                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 382
 383                                         v = new LongConstant (res);
 384                                         if (result_type == null)
 385                                                 return v;
 386                                         else
 387                                                 return new EnumConstant (v, result_type);
 388                                 } else if (left is ULongConstant){
 389                                         ULongConstant v;
 390                                         ulong res = ((ULongConstant)left).Value ^
 391                                                 ((ULongConstant)right).Value;
 392
 393                                         v = new ULongConstant (res);
 394                                         if (result_type == null)
 395                                                 return v;
 396                                         else
 397                                                 return new EnumConstant (v, result_type);
 398                                 } else if (left is UShortConstant){
 399                                         UShortConstant v;
 400                                         ushort res = (ushort) (((UShortConstant)left).Value ^
 401                                                                ((UShortConstant)right).Value);
 402
 403                                         v = new UShortConstant (res);
 404                                         if (result_type == null)
 405                                                 return v;
 406                                         else
 407                                                 return new EnumConstant (v, result_type);
 408                                 } else if (left is ShortConstant){
 409                                         ShortConstant v;
 410                                         short res = (short)(((ShortConstant)left).Value ^
 411                                                             ((ShortConstant)right).Value);
 412
 413                                         v = new ShortConstant (res);
 414                                         if (result_type == null)
 415                                                 return v;
 416                                         else
 417                                                 return new EnumConstant (v, result_type);
 418                                 }
 419                                 break;
 420
 421                         case Binary.Operator.Addition:
 422                                 bool left_is_string = left is StringConstant;
 423                                 bool right_is_string = right is StringConstant;
 424
 425                                 //
 426                                 // If both sides are strings, then concatenate, if
 427                                 // one is a string, and the other is not, then defer
 428                                 // to runtime concatenation
 429                                 //
 430                                 wrap_as = null;
 431                                 if (left_is_string || right_is_string){
 432                                         if (left_is_string && right_is_string)
 433                                                 return new StringConstant (
 434                                                         ((StringConstant) left).Value +
 435                                                         ((StringConstant) right).Value);
 436
 437                                         return null;
 438                                 }
 439
 440                                 //
 441                                 // handle "E operator + (E x, U y)"
 442                                 // handle "E operator + (Y y, E x)"
 443                                 //
 444                                 // note that E operator + (E x, E y) is invalid
 445                                 //
 446                                 if (left is EnumConstant){
 447                                         if (right is EnumConstant){
 448                                                 return null;
 449                                         }
 450                                         if (((EnumConstant) left).Child.Type != right.Type)
 451                                                 return null;
 452
 453                                         wrap_as = left.Type;
 454                                 } else if (right is EnumConstant){
 455                                         if (((EnumConstant) right).Child.Type != left.Type)
 456                                                 return null;
 457                                         wrap_as = right.Type;
 458                                 }
 459
 460                                 result = null;
 461                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 462                                 if (left == null || right == null)
 463                                         return null;
 464
 465                                 try {
 466                                         if (left is DoubleConstant){
 467                                                 double res;
 468
 469                                                 if (ec.ConstantCheckState)
 470                                                         res = checked (((DoubleConstant) left).Value +
 471                                                                        ((DoubleConstant) right).Value);
 472                                                 else
 473                                                         res = unchecked (((DoubleConstant) left).Value +
 474                                                                          ((DoubleConstant) right).Value);
 475
 476                                                 result = new DoubleConstant (res);
 477                                         } else if (left is FloatConstant){
 478                                                 float res;
 479
 480                                                 if (ec.ConstantCheckState)
 481                                                         res = checked (((FloatConstant) left).Value +
 482                                                                        ((FloatConstant) right).Value);
 483                                                 else
 484                                                         res = unchecked (((FloatConstant) left).Value +
 485                                                                          ((FloatConstant) right).Value);
 486
 487                                                 result = new FloatConstant (res);
 488                                         } else if (left is ULongConstant){
 489                                                 ulong res;
 490
 491                                                 if (ec.ConstantCheckState)
 492                                                         res = checked (((ULongConstant) left).Value +
 493                                                                        ((ULongConstant) right).Value);
 494                                                 else
 495                                                         res = unchecked (((ULongConstant) left).Value +
 496                                                                          ((ULongConstant) right).Value);
 497
 498                                                 result = new ULongConstant (res);
 499                                         } else if (left is LongConstant){
 500                                                 long res;
 501
 502                                                 if (ec.ConstantCheckState)
 503                                                         res = checked (((LongConstant) left).Value +
 504                                                                        ((LongConstant) right).Value);
 505                                                 else
 506                                                         res = unchecked (((LongConstant) left).Value +
 507                                                                          ((LongConstant) right).Value);
 508
 509                                                 result = new LongConstant (res);
 510                                         } else if (left is UIntConstant){
 511                                                 uint res;
 512
 513                                                 if (ec.ConstantCheckState)
 514                                                         res = checked (((UIntConstant) left).Value +
 515                                                                        ((UIntConstant) right).Value);
 516                                                 else
 517                                                         res = unchecked (((UIntConstant) left).Value +
 518                                                                          ((UIntConstant) right).Value);
 519
 520                                                 result = new UIntConstant (res);
 521                                         } else if (left is IntConstant){
 522                                                 int res;
 523
 524                                                 if (ec.ConstantCheckState)
 525                                                         res = checked (((IntConstant) left).Value +
 526                                                                        ((IntConstant) right).Value);
 527                                                 else
 528                                                         res = unchecked (((IntConstant) left).Value +
 529                                                                          ((IntConstant) right).Value);
 530
 531                                                 result = new IntConstant (res);
 532                                         } else {
 533                                                 throw new Exception ( "Unexepected addition input: " + left);
 534                                         }
 535                                 } catch (OverflowException){
 536                                         Error_CompileTimeOverflow (loc);
 537                                 }
 538
 539                                 if (wrap_as != null)
 540                                         return new EnumConstant (result, wrap_as);
 541                                 else
 542                                         return result;
 543
 544                         case Binary.Operator.Subtraction:
 545                                 //
 546                                 // handle "E operator - (E x, U y)"
 547                                 // handle "E operator - (Y y, E x)"
 548                                 // handle "U operator - (E x, E y)"
 549                                 //
 550                                 wrap_as = null;
 551                                 if (left is EnumConstant){
 552                                         if (right is EnumConstant){
 553                                                 if (left.Type == right.Type)
 554                                                         wrap_as = TypeManager.EnumToUnderlying (left.Type);
 555                                                 else
 556                                                         return null;
 557                                         }
 558                                         if (((EnumConstant) left).Child.Type != right.Type)
 559                                                 return null;
 560
 561                                         wrap_as = left.Type;
 562                                 } else if (right is EnumConstant){
 563                                         if (((EnumConstant) right).Child.Type != left.Type)
 564                                                 return null;
 565                                         wrap_as = right.Type;
 566                                 }
 567
 568                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 569                                 if (left == null || right == null)
 570                                         return null;
 571
 572                                 try {
 573                                         if (left is DoubleConstant){
 574                                                 double res;
 575
 576                                                 if (ec.ConstantCheckState)
 577                                                         res = checked (((DoubleConstant) left).Value -
 578                                                                        ((DoubleConstant) right).Value);
 579                                                 else
 580                                                         res = unchecked (((DoubleConstant) left).Value -
 581                                                                          ((DoubleConstant) right).Value);
 582
 583                                                 result = new DoubleConstant (res);
 584                                         } else if (left is FloatConstant){
 585                                                 float res;
 586
 587                                                 if (ec.ConstantCheckState)
 588                                                         res = checked (((FloatConstant) left).Value -
 589                                                                        ((FloatConstant) right).Value);
 590                                                 else
 591                                                         res = unchecked (((FloatConstant) left).Value -
 592                                                                          ((FloatConstant) right).Value);
 593
 594                                                 result = new FloatConstant (res);
 595                                         } else if (left is ULongConstant){
 596                                                 ulong res;
 597
 598                                                 if (ec.ConstantCheckState)
 599                                                         res = checked (((ULongConstant) left).Value -
 600                                                                        ((ULongConstant) right).Value);
 601                                                 else
 602                                                         res = unchecked (((ULongConstant) left).Value -
 603                                                                          ((ULongConstant) right).Value);
 604
 605                                                 result = new ULongConstant (res);
 606                                         } else if (left is LongConstant){
 607                                                 long res;
 608
 609                                                 if (ec.ConstantCheckState)
 610                                                         res = checked (((LongConstant) left).Value -
 611                                                                        ((LongConstant) right).Value);
 612                                                 else
 613                                                         res = unchecked (((LongConstant) left).Value -
 614                                                                          ((LongConstant) right).Value);
 615
 616                                                 result = new LongConstant (res);
 617                                         } else if (left is UIntConstant){
 618                                                 uint res;
 619
 620                                                 if (ec.ConstantCheckState)
 621                                                         res = checked (((UIntConstant) left).Value -
 622                                                                        ((UIntConstant) right).Value);
 623                                                 else
 624                                                         res = unchecked (((UIntConstant) left).Value -
 625                                                                          ((UIntConstant) right).Value);
 626
 627                                                 result = new UIntConstant (res);
 628                                         } else if (left is IntConstant){
 629                                                 int res;
 630
 631                                                 if (ec.ConstantCheckState)
 632                                                         res = checked (((IntConstant) left).Value -
 633                                                                        ((IntConstant) right).Value);
 634                                                 else
 635                                                         res = unchecked (((IntConstant) left).Value -
 636                                                                          ((IntConstant) right).Value);
 637
 638                                                 result = new IntConstant (res);
 639                                         } else {
 640                                                 throw new Exception ( "Unexepected subtraction input: " + left);
 641                                         }
 642                                 } catch (OverflowException){
 643                                         Error_CompileTimeOverflow (loc);
 644                                 }
 645                                 if (wrap_as != null)
 646                                         return new EnumConstant (result, wrap_as);
 647                                 else
 648                                         return result;
 649
 650                         case Binary.Operator.Multiply:
 651                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 652                                 if (left == null || right == null)
 653                                         return null;
 654
 655                                 try {
 656                                         if (left is DoubleConstant){
 657                                                 double res;
 658
 659                                                 if (ec.ConstantCheckState)
 660                                                         res = checked (((DoubleConstant) left).Value *
 661                                                                 ((DoubleConstant) right).Value);
 662                                                 else
 663                                                         res = unchecked (((DoubleConstant) left).Value *
 664                                                                 ((DoubleConstant) right).Value);
 665
 666                                                 return new DoubleConstant (res);
 667                                         } else if (left is FloatConstant){
 668                                                 float res;
 669
 670                                                 if (ec.ConstantCheckState)
 671                                                         res = checked (((FloatConstant) left).Value *
 672                                                                 ((FloatConstant) right).Value);
 673                                                 else
 674                                                         res = unchecked (((FloatConstant) left).Value *
 675                                                                 ((FloatConstant) right).Value);
 676
 677                                                 return new FloatConstant (res);
 678                                         } else if (left is ULongConstant){
 679                                                 ulong res;
 680
 681                                                 if (ec.ConstantCheckState)
 682                                                         res = checked (((ULongConstant) left).Value *
 683                                                                 ((ULongConstant) right).Value);
 684                                                 else
 685                                                         res = unchecked (((ULongConstant) left).Value *
 686                                                                 ((ULongConstant) right).Value);
 687
 688                                                 return new ULongConstant (res);
 689                                         } else if (left is LongConstant){
 690                                                 long res;
 691
 692                                                 if (ec.ConstantCheckState)
 693                                                         res = checked (((LongConstant) left).Value *
 694                                                                 ((LongConstant) right).Value);
 695                                                 else
 696                                                         res = unchecked (((LongConstant) left).Value *
 697                                                                 ((LongConstant) right).Value);
 698
 699                                                 return new LongConstant (res);
 700                                         } else if (left is UIntConstant){
 701                                                 uint res;
 702
 703                                                 if (ec.ConstantCheckState)
 704                                                         res = checked (((UIntConstant) left).Value *
 705                                                                 ((UIntConstant) right).Value);
 706                                                 else
 707                                                         res = unchecked (((UIntConstant) left).Value *
 708                                                                 ((UIntConstant) right).Value);
 709
 710                                                 return new UIntConstant (res);
 711                                         } else if (left is IntConstant){
 712                                                 int res;
 713
 714                                                 if (ec.ConstantCheckState)
 715                                                         res = checked (((IntConstant) left).Value *
 716                                                                 ((IntConstant) right).Value);
 717                                                 else
 718                                                         res = unchecked (((IntConstant) left).Value *
 719                                                                 ((IntConstant) right).Value);
 720
 721                                                 return new IntConstant (res);
 722                                         } else if (left is DecimalConstant) {
 723                                                 decimal res;
 724
 725                                                 if (ec.ConstantCheckState)
 726                                                         res = checked (((DecimalConstant) left).Value *
 727                                                                 ((DecimalConstant) right).Value);
 728                                                 else
 729                                                         res = unchecked (((DecimalConstant) left).Value *
 730                                                                 ((DecimalConstant) right).Value);
 731
 732                                                 return new DecimalConstant (res);
 733                                         } else {
 734                                                 throw new Exception ( "Unexepected multiply input: " + left);
 735                                         }
 736                                 } catch (OverflowException){
 737                                         Error_CompileTimeOverflow (loc);
 738                                 }
 739                                 break;
 740
 741                         case Binary.Operator.Division:
 742                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 743                                 if (left == null || right == null)
 744                                         return null;
 745
 746                                 try {
 747                                         if (left is DoubleConstant){
 748                                                 double res;
 749
 750                                                 if (ec.ConstantCheckState)
 751                                                         res = checked (((DoubleConstant) left).Value /
 752                                                                 ((DoubleConstant) right).Value);
 753                                                 else
 754                                                         res = unchecked (((DoubleConstant) left).Value /
 755                                                                 ((DoubleConstant) right).Value);
 756
 757                                                 return new DoubleConstant (res);
 758                                         } else if (left is FloatConstant){
 759                                                 float res;
 760
 761                                                 if (ec.ConstantCheckState)
 762                                                         res = checked (((FloatConstant) left).Value /
 763                                                                 ((FloatConstant) right).Value);
 764                                                 else
 765                                                         res = unchecked (((FloatConstant) left).Value /
 766                                                                 ((FloatConstant) right).Value);
 767
 768                                                 return new FloatConstant (res);
 769                                         } else if (left is ULongConstant){
 770                                                 ulong res;
 771
 772                                                 if (ec.ConstantCheckState)
 773                                                         res = checked (((ULongConstant) left).Value /
 774                                                                 ((ULongConstant) right).Value);
 775                                                 else
 776                                                         res = unchecked (((ULongConstant) left).Value /
 777                                                                 ((ULongConstant) right).Value);
 778
 779                                                 return new ULongConstant (res);
 780                                         } else if (left is LongConstant){
 781                                                 long res;
 782
 783                                                 if (ec.ConstantCheckState)
 784                                                         res = checked (((LongConstant) left).Value /
 785                                                                 ((LongConstant) right).Value);
 786                                                 else
 787                                                         res = unchecked (((LongConstant) left).Value /
 788                                                                 ((LongConstant) right).Value);
 789
 790                                                 return new LongConstant (res);
 791                                         } else if (left is UIntConstant){
 792                                                 uint res;
 793
 794                                                 if (ec.ConstantCheckState)
 795                                                         res = checked (((UIntConstant) left).Value /
 796                                                                 ((UIntConstant) right).Value);
 797                                                 else
 798                                                         res = unchecked (((UIntConstant) left).Value /
 799                                                                 ((UIntConstant) right).Value);
 800
 801                                                 return new UIntConstant (res);
 802                                         } else if (left is IntConstant){
 803                                                 int res;
 804
 805                                                 if (ec.ConstantCheckState)
 806                                                         res = checked (((IntConstant) left).Value /
 807                                                                 ((IntConstant) right).Value);
 808                                                 else
 809                                                         res = unchecked (((IntConstant) left).Value /
 810                                                                 ((IntConstant) right).Value);
 811
 812                                                 return new IntConstant (res);
 813                                         } else if (left is DecimalConstant) {
 814                                                 decimal res;
 815
 816                                                 if (ec.ConstantCheckState)
 817                                                         res = checked (((DecimalConstant) left).Value /
 818                                                                 ((DecimalConstant) right).Value);
 819                                                 else
 820                                                         res = unchecked (((DecimalConstant) left).Value /
 821                                                                 ((DecimalConstant) right).Value);
 822
 823                                                 return new DecimalConstant (res);
 824                                         } else {
 825                                                 throw new Exception ( "Unexepected division input: " + left);
 826                                         }
 827                                 } catch (OverflowException){
 828                                         Error_CompileTimeOverflow (loc);
 829
 830                                 } catch (DivideByZeroException) {
 831                                         Report.Error (020, loc, "Division by constant zero");
 832                                 }
 833
 834                                 break;
 835
 836                         case Binary.Operator.Modulus:
 837                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 838                                 if (left == null || right == null)
 839                                         return null;
 840
 841                                 try {
 842                                         if (left is DoubleConstant){
 843                                                 double res;
 844
 845                                                 if (ec.ConstantCheckState)
 846                                                         res = checked (((DoubleConstant) left).Value %
 847                                                                        ((DoubleConstant) right).Value);
 848                                                 else
 849                                                         res = unchecked (((DoubleConstant) left).Value %
 850                                                                          ((DoubleConstant) right).Value);
 851
 852                                                 return new DoubleConstant (res);
 853                                         } else if (left is FloatConstant){
 854                                                 float res;
 855
 856                                                 if (ec.ConstantCheckState)
 857                                                         res = checked (((FloatConstant) left).Value %
 858                                                                        ((FloatConstant) right).Value);
 859                                                 else
 860                                                         res = unchecked (((FloatConstant) left).Value %
 861                                                                          ((FloatConstant) right).Value);
 862
 863                                                 return new FloatConstant (res);
 864                                         } else if (left is ULongConstant){
 865                                                 ulong res;
 866
 867                                                 if (ec.ConstantCheckState)
 868                                                         res = checked (((ULongConstant) left).Value %
 869                                                                        ((ULongConstant) right).Value);
 870                                                 else
 871                                                         res = unchecked (((ULongConstant) left).Value %
 872                                                                          ((ULongConstant) right).Value);
 873
 874                                                 return new ULongConstant (res);
 875                                         } else if (left is LongConstant){
 876                                                 long res;
 877
 878                                                 if (ec.ConstantCheckState)
 879                                                         res = checked (((LongConstant) left).Value %
 880                                                                        ((LongConstant) right).Value);
 881                                                 else
 882                                                         res = unchecked (((LongConstant) left).Value %
 883                                                                          ((LongConstant) right).Value);
 884
 885                                                 return new LongConstant (res);
 886                                         } else if (left is UIntConstant){
 887                                                 uint res;
 888
 889                                                 if (ec.ConstantCheckState)
 890                                                         res = checked (((UIntConstant) left).Value %
 891                                                                        ((UIntConstant) right).Value);
 892                                                 else
 893                                                         res = unchecked (((UIntConstant) left).Value %
 894                                                                          ((UIntConstant) right).Value);
 895
 896                                                 return new UIntConstant (res);
 897                                         } else if (left is IntConstant){
 898                                                 int res;
 899
 900                                                 if (ec.ConstantCheckState)
 901                                                         res = checked (((IntConstant) left).Value %
 902                                                                        ((IntConstant) right).Value);
 903                                                 else
 904                                                         res = unchecked (((IntConstant) left).Value %
 905                                                                          ((IntConstant) right).Value);
 906
 907                                                 return new IntConstant (res);
 908                                         } else {
 909                                                 throw new Exception ( "Unexepected modulus input: " + left);
 910                                         }
 911                                 } catch (DivideByZeroException){
 912                                         Report.Error (020, loc, "Division by constant zero");
 913                                 } catch (OverflowException){
 914                                         Error_CompileTimeOverflow (loc);
 915                                 }
 916                                 break;
 917
 918                                 //
 919                                 // There is no overflow checking on left shift
 920                                 //
 921                         case Binary.Operator.LeftShift:
 922                                 IntConstant ic = right.ToInt (loc);
 923                                 if (ic == null){
 924                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 925                                         return null;
 926                                 }
 927                                 int lshift_val = ic.Value;
 928
 929                                 IntConstant lic;
 930                                 if ((lic = left.ConvertToInt ()) != null)
 931                                         return new IntConstant (lic.Value << lshift_val);
 932
 933                                 UIntConstant luic;
 934                                 if ((luic = left.ConvertToUInt ()) != null)
 935                                         return new UIntConstant (luic.Value << lshift_val);
 936
 937                                 LongConstant llc;
 938                                 if ((llc = left.ConvertToLong ()) != null)
 939                                         return new LongConstant (llc.Value << lshift_val);
 940
 941                                 ULongConstant lulc;
 942                                 if ((lulc = left.ConvertToULong ()) != null)
 943                                         return new ULongConstant (lulc.Value << lshift_val);
 944
 945                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 946                                 break;
 947
 948                                 //
 949                                 // There is no overflow checking on right shift
 950                                 //
 951                         case Binary.Operator.RightShift:
 952                                 IntConstant sic = right.ToInt (loc);
 953                                 if (sic == null){
 954                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 955                                         return null;
 956                                 }
 957                                 int rshift_val = sic.Value;
 958
 959                                 IntConstant ric;
 960                                 if ((ric = left.ConvertToInt ()) != null)
 961                                         return new IntConstant (ric.Value >> rshift_val);
 962
 963                                 UIntConstant ruic;
 964                                 if ((ruic = left.ConvertToUInt ()) != null)
 965                                         return new UIntConstant (ruic.Value >> rshift_val);
 966
 967                                 LongConstant rlc;
 968                                 if ((rlc = left.ConvertToLong ()) != null)
 969                                         return new LongConstant (rlc.Value >> rshift_val);
 970
 971                                 ULongConstant rulc;
 972                                 if ((rulc = left.ConvertToULong ()) != null)
 973                                         return new ULongConstant (rulc.Value >> rshift_val);
 974
 975                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 976                                 break;
 977
 978                         case Binary.Operator.LogicalAnd:
 979                                 if (left is BoolConstant && right is BoolConstant){
 980                                         return new BoolConstant (
 981                                                 ((BoolConstant) left).Value &&
 982                                                 ((BoolConstant) right).Value);
 983                                 }
 984                                 break;
 985
 986                         case Binary.Operator.LogicalOr:
 987                                 if (left is BoolConstant && right is BoolConstant){
 988                                         return new BoolConstant (
 989                                                 ((BoolConstant) left).Value ||
 990                                                 ((BoolConstant) right).Value);
 991                                 }
 992                                 break;
 993
 994                         case Binary.Operator.Equality:
 995                                 if (left is BoolConstant && right is BoolConstant){
 996                                         return new BoolConstant (
 997                                                 ((BoolConstant) left).Value ==
 998                                                 ((BoolConstant) right).Value);
 999
1000                                 }
1001                                 if (left is NullLiteral){
1002                                         if (right is NullLiteral)
1003                                                 return new BoolConstant (true);
1004                                         else if (right is StringConstant)
1005                                                 return new BoolConstant (
1006                                                         ((StringConstant) right).Value == null);
1007                                 } else if (right is NullLiteral){
1008                                         if (left is NullLiteral)
1009                                                 return new BoolConstant (true);
1010                                         else if (left is StringConstant)
1011                                                 return new BoolConstant (
1012                                                         ((StringConstant) left).Value == null);
1013                                 }
1014                                 if (left is StringConstant && right is StringConstant){
1015                                         return new BoolConstant (
1016                                                 ((StringConstant) left).Value ==
1017                                                 ((StringConstant) right).Value);
1018
1019                                 }
1020
1021                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1022                                 if (left == null || right == null)
1023                                         return null;
1024
1025                                 bool_res = false;
1026                                 if (left is DoubleConstant)
1027                                         bool_res = ((DoubleConstant) left).Value ==
1028                                                 ((DoubleConstant) right).Value;
1029                                 else if (left is FloatConstant)
1030                                         bool_res = ((FloatConstant) left).Value ==
1031                                                 ((FloatConstant) right).Value;
1032                                 else if (left is ULongConstant)
1033                                         bool_res = ((ULongConstant) left).Value ==
1034                                                 ((ULongConstant) right).Value;
1035                                 else if (left is LongConstant)
1036                                         bool_res = ((LongConstant) left).Value ==
1037                                                 ((LongConstant) right).Value;
1038                                 else if (left is UIntConstant)
1039                                         bool_res = ((UIntConstant) left).Value ==
1040                                                 ((UIntConstant) right).Value;
1041                                 else if (left is IntConstant)
1042                                         bool_res = ((IntConstant) left).Value ==
1043                                                 ((IntConstant) right).Value;
1044                                 else
1045                                         return null;
1046
1047                                 return new BoolConstant (bool_res);
1048
1049                         case Binary.Operator.Inequality:
1050                                 if (left is BoolConstant && right is BoolConstant){
1051                                         return new BoolConstant (
1052                                                 ((BoolConstant) left).Value !=
1053                                                 ((BoolConstant) right).Value);
1054                                 }
1055                                 if (left is NullLiteral){
1056                                         if (right is NullLiteral)
1057                                                 return new BoolConstant (false);
1058                                         else if (right is StringConstant)
1059                                                 return new BoolConstant (
1060                                                         ((StringConstant) right).Value != null);
1061                                 } else if (right is NullLiteral){
1062                                         if (left is NullLiteral)
1063                                                 return new BoolConstant (false);
1064                                         else if (left is StringConstant)
1065                                                 return new BoolConstant (
1066                                                         ((StringConstant) left).Value != null);
1067                                 }
1068                                 if (left is StringConstant && right is StringConstant){
1069                                         return new BoolConstant (
1070                                                 ((StringConstant) left).Value !=
1071                                                 ((StringConstant) right).Value);
1072
1073                                 }
1074                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1075                                 if (left == null || right == null)
1076                                         return null;
1077
1078                                 bool_res = false;
1079                                 if (left is DoubleConstant)
1080                                         bool_res = ((DoubleConstant) left).Value !=
1081                                                 ((DoubleConstant) right).Value;
1082                                 else if (left is FloatConstant)
1083                                         bool_res = ((FloatConstant) left).Value !=
1084                                                 ((FloatConstant) right).Value;
1085                                 else if (left is ULongConstant)
1086                                         bool_res = ((ULongConstant) left).Value !=
1087                                                 ((ULongConstant) right).Value;
1088                                 else if (left is LongConstant)
1089                                         bool_res = ((LongConstant) left).Value !=
1090                                                 ((LongConstant) right).Value;
1091                                 else if (left is UIntConstant)
1092                                         bool_res = ((UIntConstant) left).Value !=
1093                                                 ((UIntConstant) right).Value;
1094                                 else if (left is IntConstant)
1095                                         bool_res = ((IntConstant) left).Value !=
1096                                                 ((IntConstant) right).Value;
1097                                 else
1098                                         return null;
1099
1100                                 return new BoolConstant (bool_res);
1101
1102                         case Binary.Operator.LessThan:
1103                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1104                                 if (left == null || right == null)
1105                                         return null;
1106
1107                                 bool_res = false;
1108                                 if (left is DoubleConstant)
1109                                         bool_res = ((DoubleConstant) left).Value <
1110                                                 ((DoubleConstant) right).Value;
1111                                 else if (left is FloatConstant)
1112                                         bool_res = ((FloatConstant) left).Value <
1113                                                 ((FloatConstant) right).Value;
1114                                 else if (left is ULongConstant)
1115                                         bool_res = ((ULongConstant) left).Value <
1116                                                 ((ULongConstant) right).Value;
1117                                 else if (left is LongConstant)
1118                                         bool_res = ((LongConstant) left).Value <
1119                                                 ((LongConstant) right).Value;
1120                                 else if (left is UIntConstant)
1121                                         bool_res = ((UIntConstant) left).Value <
1122                                                 ((UIntConstant) right).Value;
1123                                 else if (left is IntConstant)
1124                                         bool_res = ((IntConstant) left).Value <
1125                                                 ((IntConstant) right).Value;
1126                                 else
1127                                         return null;
1128
1129                                 return new BoolConstant (bool_res);
1130
1131                         case Binary.Operator.GreaterThan:
1132                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1133                                 if (left == null || right == null)
1134                                         return null;
1135
1136                                 bool_res = false;
1137                                 if (left is DoubleConstant)
1138                                         bool_res = ((DoubleConstant) left).Value >
1139                                                 ((DoubleConstant) right).Value;
1140                                 else if (left is FloatConstant)
1141                                         bool_res = ((FloatConstant) left).Value >
1142                                                 ((FloatConstant) right).Value;
1143                                 else if (left is ULongConstant)
1144                                         bool_res = ((ULongConstant) left).Value >
1145                                                 ((ULongConstant) right).Value;
1146                                 else if (left is LongConstant)
1147                                         bool_res = ((LongConstant) left).Value >
1148                                                 ((LongConstant) right).Value;
1149                                 else if (left is UIntConstant)
1150                                         bool_res = ((UIntConstant) left).Value >
1151                                                 ((UIntConstant) right).Value;
1152                                 else if (left is IntConstant)
1153                                         bool_res = ((IntConstant) left).Value >
1154                                                 ((IntConstant) right).Value;
1155                                 else
1156                                         return null;
1157
1158                                 return new BoolConstant (bool_res);
1159
1160                         case Binary.Operator.GreaterThanOrEqual:
1161                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1162                                 if (left == null || right == null)
1163                                         return null;
1164
1165                                 bool_res = false;
1166                                 if (left is DoubleConstant)
1167                                         bool_res = ((DoubleConstant) left).Value >=
1168                                                 ((DoubleConstant) right).Value;
1169                                 else if (left is FloatConstant)
1170                                         bool_res = ((FloatConstant) left).Value >=
1171                                                 ((FloatConstant) right).Value;
1172                                 else if (left is ULongConstant)
1173                                         bool_res = ((ULongConstant) left).Value >=
1174                                                 ((ULongConstant) right).Value;
1175                                 else if (left is LongConstant)
1176                                         bool_res = ((LongConstant) left).Value >=
1177                                                 ((LongConstant) right).Value;
1178                                 else if (left is UIntConstant)
1179                                         bool_res = ((UIntConstant) left).Value >=
1180                                                 ((UIntConstant) right).Value;
1181                                 else if (left is IntConstant)
1182                                         bool_res = ((IntConstant) left).Value >=
1183                                                 ((IntConstant) right).Value;
1184                                 else
1185                                         return null;
1186
1187                                 return new BoolConstant (bool_res);
1188
1189                         case Binary.Operator.LessThanOrEqual:
1190                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1191                                 if (left == null || right == null)
1192                                         return null;
1193
1194                                 bool_res = false;
1195                                 if (left is DoubleConstant)
1196                                         bool_res = ((DoubleConstant) left).Value <=
1197                                                 ((DoubleConstant) right).Value;
1198                                 else if (left is FloatConstant)
1199                                         bool_res = ((FloatConstant) left).Value <=
1200                                                 ((FloatConstant) right).Value;
1201                                 else if (left is ULongConstant)
1202                                         bool_res = ((ULongConstant) left).Value <=
1203                                                 ((ULongConstant) right).Value;
1204                                 else if (left is LongConstant)
1205                                         bool_res = ((LongConstant) left).Value <=
1206                                                 ((LongConstant) right).Value;
1207                                 else if (left is UIntConstant)
1208                                         bool_res = ((UIntConstant) left).Value <=
1209                                                 ((UIntConstant) right).Value;
1210                                 else if (left is IntConstant)
1211                                         bool_res = ((IntConstant) left).Value <=
1212                                                 ((IntConstant) right).Value;
1213                                 else
1214                                         return null;
1215
1216                                 return new BoolConstant (bool_res);
1217                         }
1218
1219                         return null;
1220                 }
1221         }
1222 }