mcs/mbas/cfold.cs

   1 //
   2 // cfold.cs: Constant Folding
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2002 Ximian, Inc.
   8 //
   9
  10 using System;
  11
  12 namespace Mono.MonoBASIC {
  13
  14         public class ConstantFold {
  15
  16                  static public Constant ConvertNothingToDefaultConst (EmitContext ec,
  17                                                                         Type target_type, Location loc)
  18                 {
  19                         switch (Type.GetTypeCode (target_type)) {
  20                         case TypeCode.Boolean  :
  21                                 return new BoolConstant (false);
  22                         case TypeCode.Byte  :
  23                                 return new ByteConstant (0);
  24                         case TypeCode.Char  :
  25                                 return new CharConstant ((char)0);
  26                         case TypeCode.SByte :
  27                                 return new SByteConstant (0);
  28                         case TypeCode.Int16 :
  29                                 return new ShortConstant (0);
  30                         case TypeCode.Int32 :
  31                                 return new IntConstant (0);
  32                         case TypeCode.Int64 :
  33                                 return new LongConstant (0);
  34                         case TypeCode.Decimal :
  35                                 return new DecimalConstant (System.Decimal.Zero);
  36                         case TypeCode.Single :
  37                                 return new FloatConstant (0.0F);
  38                         case TypeCode.Double :
  39                                  return new DoubleConstant (0.0);
  40                         }
  41
  42                         return null;
  43                 }
  44
  45
  46                 //
  47                 // Performs the numeric promotions on the left and right expresions
  48                 // and desposits the results on `lc' and `rc'.
  49                 //
  50                 // On success, the types of `lc' and `rc' on output will always match,
  51                 // and the pair will be one of:
  52                 //
  53                 //   (double, double)
  54                 //   (float, float)
  55                 //   (ulong, ulong)
  56                 //   (long, long)
  57                 //   (uint, uint)
  58                 //   (int, int)
  59                 //
  60                 static void DoConstantNumericPromotions (EmitContext ec, Binary.Operator oper,
  61                                                          ref Constant left, ref Constant right,
  62                                                          Location loc)
  63                 {
  64
  65                         Type conv_left_as = null;
  66                         Type conv_right_as = null;
  67                         Type lt = left.Type;
  68                         Type rt = right.Type;
  69
  70
  71                         if (left is NullLiteral)
  72                                 conv_left_as = rt;
  73                         if (right is NullLiteral)
  74                                 conv_right_as = lt;
  75
  76                          if (conv_left_as != null)
  77                                 left = ConvertNothingToDefaultConst (ec, conv_left_as, loc);
  78                         if (conv_right_as != null)
  79                                 right = ConvertNothingToDefaultConst (ec, conv_right_as, loc);
  80                         if (left is DoubleConstant || right is DoubleConstant ||
  81                             oper == Binary.Operator.Exponentiation || oper == Binary.Operator.Division) {
  82                                 //
  83                                 // If either side is a double, convert the other to a double
  84                                 //
  85                                 if (!(left is DoubleConstant))
  86                                         left = left.ToDouble (loc);
  87
  88                                 if (!(right is DoubleConstant))
  89                                         right = right.ToDouble (loc);
  90                                 return;
  91                         } else if (left is FloatConstant || right is FloatConstant) {
  92                                 //
  93                                 // If either side is a float, convert the other to a float
  94                                 //
  95                                 if (!(left is FloatConstant))
  96                                         left = left.ToFloat (loc);
  97
  98                                 if (!(right is FloatConstant))
  99                                         right = right.ToFloat (loc);
 100 ;                               return;
 101                         } else if (left is ULongConstant || right is ULongConstant){
 102                                 //
 103                                 // If either operand is of type ulong, the other operand is
 104                                 // converted to type ulong.  or an error ocurrs if the other
 105                                 // operand is of type sbyte, short, int or long
 106                                 //
 107 #if WRONG
 108                                 Constant match, other;
 109 #endif
 110
 111                                 if (left is ULongConstant){
 112 #if WRONG
 113                                         other = right;
 114                                         match = left;
 115 #endif
 116                                         if (!(right is ULongConstant))
 117                                                 right = right.ToULong (loc);
 118                                 } else {
 119 #if WRONG
 120                                         other = left;
 121                                         match = right;
 122 #endif
 123                                         left = left.ToULong (loc);
 124                                 }
 125
 126 #if WRONG
 127                                 if (other is SByteConstant || other is ShortConstant ||
 128                                     other is IntConstant || other is LongConstant){
 129                                         Binary.Error_OperatorAmbiguous
 130                                                 (loc, oper, other.Type, match.Type);
 131                                         left = null;
 132                                         right = null;
 133                                 }
 134 #endif
 135                                 return;
 136                         } else if (left is LongConstant || right is LongConstant){
 137                                 //
 138                                 // If either operand is of type long, the other operand is converted
 139                                 // to type long.
 140                                 //
 141                                 if (!(left is LongConstant))
 142                                         left = left.ToLong (loc);
 143                                 else if (!(right is LongConstant))
 144                                         right = right.ToLong (loc);
 145                                 return;
 146                         } else if (left is UIntConstant || right is UIntConstant){
 147                                 //
 148                                 // If either operand is of type uint, and the other
 149                                 // operand is of type sbyte, short or int, the operands are
 150                                 // converted to type long.
 151                                 //
 152                                 Constant other;
 153                                 if (left is UIntConstant){
 154                                         other = right;
 155                                 } else {
 156                                         other = left;
 157                                 }
 158
 159                                 // Nothing to do.
 160                                 if (other is UIntConstant)
 161                                         return;
 162
 163                                 if (other is SByteConstant || other is ShortConstant ||
 164                                     other is IntConstant){
 165                                         left = left.ToLong (loc);
 166                                         right = right.ToLong (loc);
 167                                 }
 168
 169                                 return;
 170                         } else if (left is EnumConstant || right is EnumConstant){
 171                                 //
 172                                 // If either operand is an enum constant, the other one must
 173                                 // be implicitly convertable to that enum's underlying type.
 174                                 //
 175                                 EnumConstant match;
 176                                 Constant other;
 177                                 if (left is EnumConstant){
 178                                         other = right;
 179                                         match = (EnumConstant) left;
 180                                 } else {
 181                                         other = left;
 182                                         match = (EnumConstant) right;
 183                                 }
 184
 185                                 bool need_check = (other is EnumConstant) ||
 186                                         ((oper != Binary.Operator.Addition) &&
 187                                          (oper != Binary.Operator.Subtraction));
 188
 189                                 if (need_check &&
 190                                     !Expression.ImplicitConversionExists (ec, match, other.Type)) {
 191                                         Expression.Error_CannotConvertImplicit (loc, match.Type, other.Type);
 192                                         left = null;
 193                                         right = null;
 194                                         return;
 195                                 }
 196
 197                                 if (left is EnumConstant)
 198                                         left = ((EnumConstant) left).Child;
 199                                 if (right is EnumConstant)
 200                                         right = ((EnumConstant) right).Child;
 201                                 return;
 202
 203                         } else {
 204                                 //
 205                                 // Force conversions to int32
 206                                 //
 207                                 if (!(left is IntConstant))
 208                                         left = left.ToInt (loc);
 209                                 if (!(right is IntConstant))
 210                                         right = right.ToInt (loc);
 211                         }
 212                         return;
 213                 }
 214
 215                 static void Error_CompileTimeOverflow (Location loc)
 216                 {
 217                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 218                 }
 219
 220                 /// <summary>
 221                 ///   Constant expression folder for binary operations.
 222                 ///
 223                 ///   Returns null if the expression can not be folded.
 224                 /// </summary>
 225                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 226                                                      Constant left, Constant right, Location loc)
 227                 {
 228                         Type lt = left.Type;
 229                         Type rt = right.Type;
 230                         Type result_type = null;
 231                         bool bool_res;
 232
 233                         //
 234                         // Enumerator folding
 235                         //
 236                         if (rt == lt && left is EnumConstant)
 237                                 result_type = lt;
 238
 239                         //
 240                         // During an enum evaluation, we need to unwrap enumerations
 241                         //
 242                         if (ec.InEnumContext){
 243                                 if (left is EnumConstant)
 244                                         left = ((EnumConstant) left).Child;
 245
 246                                 if (right is EnumConstant)
 247                                         right = ((EnumConstant) right).Child;
 248                         }
 249
 250                         Type wrap_as;
 251                         Constant result = null;
 252                         switch (oper){
 253                         case Binary.Operator.BitwiseOr:
 254                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 255                                 if (left == null || right == null)
 256                                         return null;
 257
 258                                 if (left is IntConstant){
 259                                         IntConstant v;
 260                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 261
 262                                         v = new IntConstant (res);
 263                                         if (result_type == null)
 264                                                 return v;
 265                                         else
 266                                                 return new EnumConstant (v, result_type);
 267                                 } else if (left is UIntConstant){
 268                                         UIntConstant v;
 269                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 270
 271                                         v = new UIntConstant (res);
 272                                         if (result_type == null)
 273                                                 return v;
 274                                         else
 275                                                 return new EnumConstant (v, result_type);
 276                                 } else if (left is LongConstant){
 277                                         LongConstant v;
 278                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 279
 280                                         v = new LongConstant (res);
 281                                         if (result_type == null)
 282                                                 return v;
 283                                         else
 284                                                 return new EnumConstant (v, result_type);
 285                                 } else if (left is ULongConstant){
 286                                         ULongConstant v;
 287                                         ulong res = ((ULongConstant)left).Value |
 288                                                 ((ULongConstant)right).Value;
 289
 290                                         v = new ULongConstant (res);
 291                                         if (result_type == null)
 292                                                 return v;
 293                                         else
 294                                                 return new EnumConstant (v, result_type);
 295                                 }
 296                                 break;
 297
 298                         case Binary.Operator.BitwiseAnd:
 299                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 300                                 if (left == null || right == null)
 301                                         return null;
 302
 303                                 if (left is IntConstant){
 304                                         IntConstant v;
 305                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 306
 307                                         v = new IntConstant (res);
 308                                         if (result_type == null)
 309                                                 return v;
 310                                         else
 311                                                 return new EnumConstant (v, result_type);
 312                                 } else if (left is UIntConstant){
 313                                         UIntConstant v;
 314                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 315
 316                                         v = new UIntConstant (res);
 317                                         if (result_type == null)
 318                                                 return v;
 319                                         else
 320                                                 return new EnumConstant (v, result_type);
 321                                 } else if (left is LongConstant){
 322                                         LongConstant v;
 323                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 324
 325                                         v = new LongConstant (res);
 326                                         if (result_type == null)
 327                                                 return v;
 328                                         else
 329                                                 return new EnumConstant (v, result_type);
 330                                 } else if (left is ULongConstant){
 331                                         ULongConstant v;
 332                                         ulong res = ((ULongConstant)left).Value &
 333                                                 ((ULongConstant)right).Value;
 334
 335                                         v = new ULongConstant (res);
 336                                         if (result_type == null)
 337                                                 return v;
 338                                         else
 339                                                 return new EnumConstant (v, result_type);
 340                                 }
 341                                 break;
 342
 343                         case Binary.Operator.ExclusiveOr:
 344                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 345                                 if (left == null || right == null)
 346                                         return null;
 347
 348                                 if (left is IntConstant){
 349                                         IntConstant v;
 350                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 351
 352                                         v = new IntConstant (res);
 353                                         if (result_type == null)
 354                                                 return v;
 355                                         else
 356                                                 return new EnumConstant (v, result_type);
 357                                 } else if (left is UIntConstant){
 358                                         UIntConstant v;
 359                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 360
 361                                         v = new UIntConstant (res);
 362                                         if (result_type == null)
 363                                                 return v;
 364                                         else
 365                                                 return new EnumConstant (v, result_type);
 366                                 } else if (left is LongConstant){
 367                                         LongConstant v;
 368                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 369
 370                                         v = new LongConstant (res);
 371                                         if (result_type == null)
 372                                                 return v;
 373                                         else
 374                                                 return new EnumConstant (v, result_type);
 375                                 } else if (left is ULongConstant){
 376                                         ULongConstant v;
 377                                         ulong res = ((ULongConstant)left).Value ^
 378                                                 ((ULongConstant)right).Value;
 379
 380                                         v = new ULongConstant (res);
 381                                         if (result_type == null)
 382                                                 return v;
 383                                         else
 384                                                 return new EnumConstant (v, result_type);
 385                                 }
 386                                 break;
 387
 388                         case Binary.Operator.Addition:
 389                                 bool left_is_string = left is StringConstant;
 390                                 bool right_is_string = right is StringConstant;
 391
 392                                 //
 393                                 // If both sides are strings, then concatenate, if
 394                                 // one is a string, and the other is not, then defer
 395                                 // to runtime concatenation
 396                                 //
 397                                 wrap_as = null;
 398                                 if (left_is_string || right_is_string){
 399                                         if (left_is_string && right_is_string)
 400                                                 return new StringConstant (
 401                                                         ((StringConstant) left).Value +
 402                                                         ((StringConstant) right).Value);
 403
 404                                         return null;
 405                                 }
 406
 407                                 //
 408                                 // handle "E operator + (E x, U y)"
 409                                 // handle "E operator + (Y y, E x)"
 410                                 //
 411                                 // note that E operator + (E x, E y) is invalid
 412                                 //
 413                                 if (left is EnumConstant){
 414                                         if (right is EnumConstant){
 415                                                 return null;
 416                                         }
 417                                         if (((EnumConstant) left).Child.Type != right.Type)
 418                                                 return null;
 419
 420                                         wrap_as = left.Type;
 421                                 } else if (right is EnumConstant){
 422                                         if (((EnumConstant) right).Child.Type != left.Type)
 423                                                 return null;
 424                                         wrap_as = right.Type;
 425                                 }
 426
 427                                 result = null;
 428                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 429                                 if (left == null || right == null)
 430                                         return null;
 431
 432                                 try {
 433                                         if (left is DoubleConstant){
 434                                                 double res;
 435
 436                                                 if (ec.ConstantCheckState)
 437                                                         res = checked (((DoubleConstant) left).Value +
 438                                                                        ((DoubleConstant) right).Value);
 439                                                 else
 440                                                         res = unchecked (((DoubleConstant) left).Value +
 441                                                                          ((DoubleConstant) right).Value);
 442
 443                                                 result = new DoubleConstant (res);
 444                                         } else if (left is FloatConstant){
 445                                                 float res;
 446
 447                                                 if (ec.ConstantCheckState)
 448                                                         res = checked (((FloatConstant) left).Value +
 449                                                                        ((FloatConstant) right).Value);
 450                                                 else
 451                                                         res = unchecked (((FloatConstant) left).Value +
 452                                                                          ((FloatConstant) right).Value);
 453
 454                                                 result = new FloatConstant (res);
 455                                         } else if (left is ULongConstant){
 456                                                 ulong res;
 457
 458                                                 if (ec.ConstantCheckState)
 459                                                         res = checked (((ULongConstant) left).Value +
 460                                                                        ((ULongConstant) right).Value);
 461                                                 else
 462                                                         res = unchecked (((ULongConstant) left).Value +
 463                                                                          ((ULongConstant) right).Value);
 464
 465                                                 result = new ULongConstant (res);
 466                                         } else if (left is LongConstant){
 467                                                 long res;
 468
 469                                                 if (ec.ConstantCheckState)
 470                                                         res = checked (((LongConstant) left).Value +
 471                                                                        ((LongConstant) right).Value);
 472                                                 else
 473                                                         res = unchecked (((LongConstant) left).Value +
 474                                                                          ((LongConstant) right).Value);
 475
 476                                                 result = new LongConstant (res);
 477                                         } else if (left is UIntConstant){
 478                                                 uint res;
 479
 480                                                 if (ec.ConstantCheckState)
 481                                                         res = checked (((UIntConstant) left).Value +
 482                                                                        ((UIntConstant) right).Value);
 483                                                 else
 484                                                         res = unchecked (((UIntConstant) left).Value +
 485                                                                          ((UIntConstant) right).Value);
 486
 487                                                 result = new UIntConstant (res);
 488                                         } else if (left is IntConstant){
 489                                                 int res;
 490
 491                                                 if (ec.ConstantCheckState)
 492                                                         res = checked (((IntConstant) left).Value +
 493                                                                        ((IntConstant) right).Value);
 494                                                 else
 495                                                         res = unchecked (((IntConstant) left).Value +
 496                                                                          ((IntConstant) right).Value);
 497
 498                                                 result = new IntConstant (res);
 499                                         } else {
 500                                                 throw new Exception ( "Unexepected input: " + left);
 501                                         }
 502                                 } catch (OverflowException){
 503                                         Error_CompileTimeOverflow (loc);
 504                                 }
 505
 506                                 if (wrap_as != null)
 507                                         return new EnumConstant (result, wrap_as);
 508                                 else
 509                                         return result;
 510
 511                         case Binary.Operator.Subtraction:
 512                                 //
 513                                 // handle "E operator - (E x, U y)"
 514                                 // handle "E operator - (Y y, E x)"
 515                                 // handle "U operator - (E x, E y)"
 516                                 //
 517                                 wrap_as = null;
 518                                 if (left is EnumConstant){
 519                                         if (right is EnumConstant){
 520                                                 if (left.Type == right.Type)
 521                                                         wrap_as = TypeManager.EnumToUnderlying (left.Type);
 522                                                 else
 523                                                         return null;
 524                                         }
 525                                         if (((EnumConstant) left).Child.Type != right.Type)
 526                                                 return null;
 527
 528                                         wrap_as = left.Type;
 529                                 } else if (right is EnumConstant){
 530                                         if (((EnumConstant) right).Child.Type != left.Type)
 531                                                 return null;
 532                                         wrap_as = right.Type;
 533                                 }
 534
 535                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 536                                 if (left == null || right == null)
 537                                         return null;
 538
 539                                 try {
 540                                         if (left is DoubleConstant){
 541                                                 double res;
 542
 543                                                 if (ec.ConstantCheckState)
 544                                                         res = checked (((DoubleConstant) left).Value -
 545                                                                        ((DoubleConstant) right).Value);
 546                                                 else
 547                                                         res = unchecked (((DoubleConstant) left).Value -
 548                                                                          ((DoubleConstant) right).Value);
 549
 550                                                 result = new DoubleConstant (res);
 551                                         } else if (left is FloatConstant){
 552                                                 float res;
 553
 554                                                 if (ec.ConstantCheckState)
 555                                                         res = checked (((FloatConstant) left).Value -
 556                                                                        ((FloatConstant) right).Value);
 557                                                 else
 558                                                         res = unchecked (((FloatConstant) left).Value -
 559                                                                          ((FloatConstant) right).Value);
 560
 561                                                 result = new FloatConstant (res);
 562                                         } else if (left is ULongConstant){
 563                                                 ulong res;
 564
 565                                                 if (ec.ConstantCheckState)
 566                                                         res = checked (((ULongConstant) left).Value -
 567                                                                        ((ULongConstant) right).Value);
 568                                                 else
 569                                                         res = unchecked (((ULongConstant) left).Value -
 570                                                                          ((ULongConstant) right).Value);
 571
 572                                                 result = new ULongConstant (res);
 573                                         } else if (left is LongConstant){
 574                                                 long res;
 575
 576                                                 if (ec.ConstantCheckState)
 577                                                         res = checked (((LongConstant) left).Value -
 578                                                                        ((LongConstant) right).Value);
 579                                                 else
 580                                                         res = unchecked (((LongConstant) left).Value -
 581                                                                          ((LongConstant) right).Value);
 582
 583                                                 result = new LongConstant (res);
 584                                         } else if (left is UIntConstant){
 585                                                 uint res;
 586
 587                                                 if (ec.ConstantCheckState)
 588                                                         res = checked (((UIntConstant) left).Value -
 589                                                                        ((UIntConstant) right).Value);
 590                                                 else
 591                                                         res = unchecked (((UIntConstant) left).Value -
 592                                                                          ((UIntConstant) right).Value);
 593
 594                                                 result = new UIntConstant (res);
 595                                         } else if (left is IntConstant){
 596                                                 int res;
 597
 598                                                 if (ec.ConstantCheckState)
 599                                                         res = checked (((IntConstant) left).Value -
 600                                                                        ((IntConstant) right).Value);
 601                                                 else
 602                                                         res = unchecked (((IntConstant) left).Value -
 603                                                                          ((IntConstant) right).Value);
 604
 605                                                 result = new IntConstant (res);
 606                                         } else {
 607                                                 throw new Exception ( "Unexepected input: " + left);
 608                                         }
 609                                 } catch (OverflowException){
 610                                         Error_CompileTimeOverflow (loc);
 611                                 }
 612                                 if (wrap_as != null)
 613                                         return new EnumConstant (result, wrap_as);
 614                                 else
 615                                         return result;
 616
 617                         case Binary.Operator.Multiply:
 618                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 619                                 if (left == null || right == null)
 620                                         return null;
 621
 622                                 try {
 623                                         if (left is DoubleConstant){
 624                                                 double res;
 625
 626                                                 if (ec.ConstantCheckState)
 627                                                         res = checked (((DoubleConstant) left).Value *
 628                                                                        ((DoubleConstant) right).Value);
 629                                                 else
 630                                                         res = unchecked (((DoubleConstant) left).Value *
 631                                                                          ((DoubleConstant) right).Value);
 632
 633                                                 return new DoubleConstant (res);
 634                                         } else if (left is FloatConstant){
 635                                                 float res;
 636
 637                                                 if (ec.ConstantCheckState)
 638                                                         res = checked (((FloatConstant) left).Value *
 639                                                                        ((FloatConstant) right).Value);
 640                                                 else
 641                                                         res = unchecked (((FloatConstant) left).Value *
 642                                                                          ((FloatConstant) right).Value);
 643
 644                                                 return new FloatConstant (res);
 645                                         } else if (left is ULongConstant){
 646                                                 ulong res;
 647
 648                                                 if (ec.ConstantCheckState)
 649                                                         res = checked (((ULongConstant) left).Value *
 650                                                                        ((ULongConstant) right).Value);
 651                                                 else
 652                                                         res = unchecked (((ULongConstant) left).Value *
 653                                                                          ((ULongConstant) right).Value);
 654
 655                                                 return new ULongConstant (res);
 656                                         } else if (left is LongConstant){
 657                                                 long res;
 658
 659                                                 if (ec.ConstantCheckState)
 660                                                         res = checked (((LongConstant) left).Value *
 661                                                                        ((LongConstant) right).Value);
 662                                                 else
 663                                                         res = unchecked (((LongConstant) left).Value *
 664                                                                          ((LongConstant) right).Value);
 665
 666                                                 return new LongConstant (res);
 667                                         } else if (left is UIntConstant){
 668                                                 uint res;
 669
 670                                                 if (ec.ConstantCheckState)
 671                                                         res = checked (((UIntConstant) left).Value *
 672                                                                        ((UIntConstant) right).Value);
 673                                                 else
 674                                                         res = unchecked (((UIntConstant) left).Value *
 675                                                                          ((UIntConstant) right).Value);
 676
 677                                                 return new UIntConstant (res);
 678                                         } else if (left is IntConstant){
 679                                                 int res;
 680
 681                                                 if (ec.ConstantCheckState)
 682                                                         res = checked (((IntConstant) left).Value *
 683                                                                        ((IntConstant) right).Value);
 684                                                 else
 685                                                         res = unchecked (((IntConstant) left).Value *
 686                                                                          ((IntConstant) right).Value);
 687
 688                                                 return new IntConstant (res);
 689                                         } else {
 690                                                 throw new Exception ( "Unexepected input: " + left);
 691                                         }
 692                                 } catch (OverflowException){
 693                                         Error_CompileTimeOverflow (loc);
 694                                 }
 695                                 break;
 696
 697                         case Binary.Operator.IntDivision:
 698                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 699                                 if (left == null || right == null)
 700                                         return null;
 701
 702                                 try {
 703                                         if (Mono.MonoBASIC.Parser.OptionStrict && (!(left is LongConstant) && !(left is IntConstant)) )
 704                                         {
 705                                                 Expression.Error_CannotConvertTypeStrict (left.Type, Type.GetType("System.Int64"), loc);
 706
 707                                                 return null;
 708                                         }
 709
 710                                         if (left is DoubleConstant) {
 711                                                 long left_val, right_val, res;
 712                                                 left_val = (long) ((DoubleConstant) left).Value;
 713                                                 right_val = (long) ((DoubleConstant) right).Value;
 714
 715                                                 if (ec.ConstantCheckState)
 716                                                         res = checked (left_val / right_val);
 717                                                 else
 718                                                         res = unchecked (left_val / right_val);
 719
 720                                                 return new LongConstant (res);
 721                                         } else if (left is FloatConstant) {
 722                                                 long left_val, right_val, res;
 723                                                 left_val = (long) ((FloatConstant) left).Value;
 724                                                 right_val = (long) ((FloatConstant) right).Value;
 725
 726                                                 if (ec.ConstantCheckState)
 727                                                         res = checked (left_val / right_val);
 728                                                 else
 729                                                         res = unchecked (left_val / right_val);
 730
 731                                                 return new LongConstant (res);
 732                                         } else if (left is DecimalConstant) {
 733                                                 long left_val, right_val, res;
 734                                                 left_val = (long) ((DecimalConstant) left).Value;
 735                                                 right_val = (long) ((DecimalConstant) right).Value;
 736
 737                                                 if (ec.ConstantCheckState)
 738                                                         res = checked (left_val / right_val);
 739                                                 else
 740                                                         res = unchecked (left_val / right_val);
 741
 742                                                 return new LongConstant (res);
 743                                         } else if (left is LongConstant) {
 744                                                 long res;
 745
 746                                                 if (ec.ConstantCheckState)
 747                                                         res = checked (((LongConstant) left).Value /
 748                                                                        ((LongConstant) right).Value);
 749                                                 else
 750                                                         res = unchecked (((LongConstant) left).Value /
 751                                                                          ((LongConstant) right).Value);
 752
 753                                                 return new LongConstant (res);
 754                                         } else {
 755                                                 int res;
 756
 757                                                 if (ec.ConstantCheckState)
 758                                                         res = checked (((IntConstant) left).Value /
 759                                                                        ((IntConstant) right).Value);
 760                                                 else
 761                                                         res = unchecked (((IntConstant) left).Value /
 762                                                                          ((IntConstant) right).Value);
 763
 764                                                 return new IntConstant (res);
 765                                         }
 766                                 } catch (OverflowException){
 767                                         Error_CompileTimeOverflow (loc);
 768
 769                                 } catch (DivideByZeroException) {
 770                                         Report.Error (30542, loc, "Division by constant zero");
 771                                 }
 772
 773                                 break;
 774                         case Binary.Operator.Division:
 775                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 776                                 if (left == null || right == null)
 777                                         return null;
 778
 779                                 try {
 780                                         double res;
 781
 782                                         if (ec.ConstantCheckState)
 783                                                 res = checked (((DoubleConstant) left).Value /
 784                                                                ((DoubleConstant) right).Value);
 785                                         else
 786                                                 res = unchecked (((DoubleConstant) left).Value /
 787                                                                  ((DoubleConstant) right).Value);
 788
 789                                         return new DoubleConstant (res);
 790                                 } catch (OverflowException){
 791                                         Error_CompileTimeOverflow (loc);
 792
 793                                 } catch (DivideByZeroException) {
 794                                         Report.Error (30542, loc, "Division by constant zero");
 795                                 }
 796
 797                                 break;
 798
 799                         case Binary.Operator.Modulus:
 800                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 801                                 if (left == null || right == null)
 802                                         return null;
 803
 804                                 try {
 805                                         if (left is DoubleConstant){
 806                                                 double res;
 807
 808                                                 if (ec.ConstantCheckState)
 809                                                         res = checked (((DoubleConstant) left).Value %
 810                                                                        ((DoubleConstant) right).Value);
 811                                                 else
 812                                                         res = unchecked (((DoubleConstant) left).Value %
 813                                                                          ((DoubleConstant) right).Value);
 814
 815                                                 return new DoubleConstant (res);
 816                                         } else if (left is FloatConstant){
 817                                                 float res;
 818
 819                                                 if (ec.ConstantCheckState)
 820                                                         res = checked (((FloatConstant) left).Value %
 821                                                                        ((FloatConstant) right).Value);
 822                                                 else
 823                                                         res = unchecked (((FloatConstant) left).Value %
 824                                                                          ((FloatConstant) right).Value);
 825
 826                                                 return new FloatConstant (res);
 827                                         } else if (left is ULongConstant){
 828                                                 ulong res;
 829
 830                                                 if (ec.ConstantCheckState)
 831                                                         res = checked (((ULongConstant) left).Value %
 832                                                                        ((ULongConstant) right).Value);
 833                                                 else
 834                                                         res = unchecked (((ULongConstant) left).Value %
 835                                                                          ((ULongConstant) right).Value);
 836
 837                                                 return new ULongConstant (res);
 838                                         } else if (left is LongConstant){
 839                                                 long res;
 840
 841                                                 if (ec.ConstantCheckState)
 842                                                         res = checked (((LongConstant) left).Value %
 843                                                                        ((LongConstant) right).Value);
 844                                                 else
 845                                                         res = unchecked (((LongConstant) left).Value %
 846                                                                          ((LongConstant) right).Value);
 847
 848                                                 return new LongConstant (res);
 849                                         } else if (left is UIntConstant){
 850                                                 uint res;
 851
 852                                                 if (ec.ConstantCheckState)
 853                                                         res = checked (((UIntConstant) left).Value %
 854                                                                        ((UIntConstant) right).Value);
 855                                                 else
 856                                                         res = unchecked (((UIntConstant) left).Value %
 857                                                                          ((UIntConstant) right).Value);
 858
 859                                                 return new UIntConstant (res);
 860                                         } else if (left is IntConstant){
 861                                                 int res;
 862
 863                                                 if (ec.ConstantCheckState)
 864                                                         res = checked (((IntConstant) left).Value %
 865                                                                        ((IntConstant) right).Value);
 866                                                 else
 867                                                         res = unchecked (((IntConstant) left).Value %
 868                                                                          ((IntConstant) right).Value);
 869
 870                                                 return new IntConstant (res);
 871                                         } else {
 872                                                 throw new Exception ( "Unexepected input: " + left);
 873                                         }
 874                                 } catch (OverflowException){
 875                                         Error_CompileTimeOverflow (loc);
 876
 877                                 } catch (DivideByZeroException) {
 878                                         Report.Error (30542, loc, "Division by constant zero");
 879                                 }
 880                                 break;
 881
 882                         case Binary.Operator.Exponentiation:
 883                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 884                                 if (left == null || right == null)
 885                                         return null;
 886
 887                                 double powVal = System.Math.Pow(((DoubleConstant) left).Value,
 888                                                                 ((DoubleConstant) right).Value);
 889
 890                                 return new DoubleConstant(powVal);
 891
 892                                 //
 893                                 // There is no overflow checking on left shift
 894                                 //
 895                         case Binary.Operator.LeftShift:
 896                                 IntConstant ic = right.ToInt (loc);
 897                                 if (ic == null){
 898                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 899                                         return null;
 900                                 }
 901                                 int lshift_val = ic.Value;
 902
 903                                 IntConstant lic;
 904                                 if ((lic = left.ConvertToInt ()) != null)
 905                                         return new IntConstant (lic.Value << lshift_val);
 906
 907                                 UIntConstant luic;
 908                                 if ((luic = left.ConvertToUInt ()) != null)
 909                                         return new UIntConstant (luic.Value << lshift_val);
 910
 911                                 LongConstant llc;
 912                                 if ((llc = left.ConvertToLong ()) != null)
 913                                         return new LongConstant (llc.Value << lshift_val);
 914
 915                                 ULongConstant lulc;
 916                                 if ((lulc = left.ConvertToULong ()) != null)
 917                                         return new ULongConstant (lulc.Value << lshift_val);
 918
 919                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 920                                 break;
 921
 922                                 //
 923                                 // There is no overflow checking on right shift
 924                                 //
 925                         case Binary.Operator.RightShift:
 926                                 IntConstant sic = right.ToInt (loc);
 927                                 if (sic == null){
 928                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 929                                         return null;
 930                                 }
 931                                 int rshift_val = sic.Value;
 932
 933                                 IntConstant ric;
 934                                 if ((ric = left.ConvertToInt ()) != null)
 935                                         return new IntConstant (ric.Value >> rshift_val);
 936
 937                                 UIntConstant ruic;
 938                                 if ((ruic = left.ConvertToUInt ()) != null)
 939                                         return new UIntConstant (ruic.Value >> rshift_val);
 940
 941                                 LongConstant rlc;
 942                                 if ((rlc = left.ConvertToLong ()) != null)
 943                                         return new LongConstant (rlc.Value >> rshift_val);
 944
 945                                 ULongConstant rulc;
 946                                 if ((rulc = left.ConvertToULong ()) != null)
 947                                         return new ULongConstant (rulc.Value >> rshift_val);
 948
 949                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 950                                 break;
 951
 952                         case Binary.Operator.LogicalAnd:
 953                                 if (left is BoolConstant && right is BoolConstant){
 954                                         return new BoolConstant (
 955                                                 ((BoolConstant) left).Value &&
 956                                                 ((BoolConstant) right).Value);
 957                                 }
 958                                 break;
 959
 960                         case Binary.Operator.LogicalOr:
 961                                 if (left is BoolConstant && right is BoolConstant){
 962                                         return new BoolConstant (
 963                                                 ((BoolConstant) left).Value ||
 964                                                 ((BoolConstant) right).Value);
 965                                 }
 966                                 break;
 967
 968                         case Binary.Operator.Equality:
 969                                 if (left is BoolConstant && right is BoolConstant){
 970                                         return new BoolConstant (
 971                                                 ((BoolConstant) left).Value ==
 972                                                 ((BoolConstant) right).Value);
 973
 974                                 }
 975                                 if (left is StringConstant && right is StringConstant){
 976                                         return new BoolConstant (
 977                                                 ((StringConstant) left).Value ==
 978                                                 ((StringConstant) right).Value);
 979
 980                                 }
 981
 982                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 983                                 if (left == null || right == null)
 984                                         return null;
 985
 986                                 bool_res = false;
 987                                 if (left is DoubleConstant)
 988                                         bool_res = ((DoubleConstant) left).Value ==
 989                                                 ((DoubleConstant) right).Value;
 990                                 else if (left is FloatConstant)
 991                                         bool_res = ((FloatConstant) left).Value ==
 992                                                 ((FloatConstant) right).Value;
 993                                 else if (left is ULongConstant)
 994                                         bool_res = ((ULongConstant) left).Value ==
 995                                                 ((ULongConstant) right).Value;
 996                                 else if (left is LongConstant)
 997                                         bool_res = ((LongConstant) left).Value ==
 998                                                 ((LongConstant) right).Value;
 999                                 else if (left is UIntConstant)
1000                                         bool_res = ((UIntConstant) left).Value ==
1001                                                 ((UIntConstant) right).Value;
1002                                 else if (left is IntConstant)
1003                                         bool_res = ((IntConstant) left).Value ==
1004                                                 ((IntConstant) right).Value;
1005                                 else
1006                                         return null;
1007
1008                                 return new BoolConstant (bool_res);
1009
1010                         case Binary.Operator.Inequality:
1011                                 if (left is BoolConstant && right is BoolConstant){
1012                                         return new BoolConstant (
1013                                                 ((BoolConstant) left).Value !=
1014                                                 ((BoolConstant) right).Value);
1015                                 }
1016                                 if (left is StringConstant && right is StringConstant){
1017                                         return new BoolConstant (
1018                                                 ((StringConstant) left).Value !=
1019                                                 ((StringConstant) right).Value);
1020
1021                                 }
1022                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1023                                 if (left == null || right == null)
1024                                         return null;
1025
1026                                 bool_res = false;
1027                                 if (left is DoubleConstant)
1028                                         bool_res = ((DoubleConstant) left).Value !=
1029                                                 ((DoubleConstant) right).Value;
1030                                 else if (left is FloatConstant)
1031                                         bool_res = ((FloatConstant) left).Value !=
1032                                                 ((FloatConstant) right).Value;
1033                                 else if (left is ULongConstant)
1034                                         bool_res = ((ULongConstant) left).Value !=
1035                                                 ((ULongConstant) right).Value;
1036                                 else if (left is LongConstant)
1037                                         bool_res = ((LongConstant) left).Value !=
1038                                                 ((LongConstant) right).Value;
1039                                 else if (left is UIntConstant)
1040                                         bool_res = ((UIntConstant) left).Value !=
1041                                                 ((UIntConstant) right).Value;
1042                                 else if (left is IntConstant)
1043                                         bool_res = ((IntConstant) left).Value !=
1044                                                 ((IntConstant) right).Value;
1045                                 else
1046                                         return null;
1047
1048                                 return new BoolConstant (bool_res);
1049
1050                         case Binary.Operator.LessThan:
1051                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1052                                 if (left == null || right == null)
1053                                         return null;
1054
1055                                 bool_res = false;
1056                                 if (left is DoubleConstant)
1057                                         bool_res = ((DoubleConstant) left).Value <
1058                                                 ((DoubleConstant) right).Value;
1059                                 else if (left is FloatConstant)
1060                                         bool_res = ((FloatConstant) left).Value <
1061                                                 ((FloatConstant) right).Value;
1062                                 else if (left is ULongConstant)
1063                                         bool_res = ((ULongConstant) left).Value <
1064                                                 ((ULongConstant) right).Value;
1065                                 else if (left is LongConstant)
1066                                         bool_res = ((LongConstant) left).Value <
1067                                                 ((LongConstant) right).Value;
1068                                 else if (left is UIntConstant)
1069                                         bool_res = ((UIntConstant) left).Value <
1070                                                 ((UIntConstant) right).Value;
1071                                 else if (left is IntConstant)
1072                                         bool_res = ((IntConstant) left).Value <
1073                                                 ((IntConstant) right).Value;
1074                                 else
1075                                         return null;
1076
1077                                 return new BoolConstant (bool_res);
1078
1079                         case Binary.Operator.GreaterThan:
1080                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1081                                 if (left == null || right == null)
1082                                         return null;
1083
1084                                 bool_res = false;
1085                                 if (left is DoubleConstant)
1086                                         bool_res = ((DoubleConstant) left).Value >
1087                                                 ((DoubleConstant) right).Value;
1088                                 else if (left is FloatConstant)
1089                                         bool_res = ((FloatConstant) left).Value >
1090                                                 ((FloatConstant) right).Value;
1091                                 else if (left is ULongConstant)
1092                                         bool_res = ((ULongConstant) left).Value >
1093                                                 ((ULongConstant) right).Value;
1094                                 else if (left is LongConstant)
1095                                         bool_res = ((LongConstant) left).Value >
1096                                                 ((LongConstant) right).Value;
1097                                 else if (left is UIntConstant)
1098                                         bool_res = ((UIntConstant) left).Value >
1099                                                 ((UIntConstant) right).Value;
1100                                 else if (left is IntConstant)
1101                                         bool_res = ((IntConstant) left).Value >
1102                                                 ((IntConstant) right).Value;
1103                                 else
1104                                         return null;
1105
1106                                 return new BoolConstant (bool_res);
1107
1108                         case Binary.Operator.GreaterThanOrEqual:
1109                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1110                                 if (left == null || right == null)
1111                                         return null;
1112
1113                                 bool_res = false;
1114                                 if (left is DoubleConstant)
1115                                         bool_res = ((DoubleConstant) left).Value >=
1116                                                 ((DoubleConstant) right).Value;
1117                                 else if (left is FloatConstant)
1118                                         bool_res = ((FloatConstant) left).Value >=
1119                                                 ((FloatConstant) right).Value;
1120                                 else if (left is ULongConstant)
1121                                         bool_res = ((ULongConstant) left).Value >=
1122                                                 ((ULongConstant) right).Value;
1123                                 else if (left is LongConstant)
1124                                         bool_res = ((LongConstant) left).Value >=
1125                                                 ((LongConstant) right).Value;
1126                                 else if (left is UIntConstant)
1127                                         bool_res = ((UIntConstant) left).Value >=
1128                                                 ((UIntConstant) right).Value;
1129                                 else if (left is IntConstant)
1130                                         bool_res = ((IntConstant) left).Value >=
1131                                                 ((IntConstant) right).Value;
1132                                 else
1133                                         return null;
1134
1135                                 return new BoolConstant (bool_res);
1136
1137                         case Binary.Operator.LessThanOrEqual:
1138                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1139                                 if (left == null || right == null)
1140                                         return null;
1141
1142                                 bool_res = false;
1143                                 if (left is DoubleConstant)
1144                                         bool_res = ((DoubleConstant) left).Value <=
1145                                                 ((DoubleConstant) right).Value;
1146                                 else if (left is FloatConstant)
1147                                         bool_res = ((FloatConstant) left).Value <=
1148                                                 ((FloatConstant) right).Value;
1149                                 else if (left is ULongConstant)
1150                                         bool_res = ((ULongConstant) left).Value <=
1151                                                 ((ULongConstant) right).Value;
1152                                 else if (left is LongConstant)
1153                                         bool_res = ((LongConstant) left).Value <=
1154                                                 ((LongConstant) right).Value;
1155                                 else if (left is UIntConstant)
1156                                         bool_res = ((UIntConstant) left).Value <=
1157                                                 ((UIntConstant) right).Value;
1158                                 else if (left is IntConstant)
1159                                         bool_res = ((IntConstant) left).Value <=
1160                                                 ((IntConstant) right).Value;
1161                                 else
1162                                         return null;
1163
1164                                 return new BoolConstant (bool_res);
1165                         }
1166
1167                         return null;
1168                 }
1169         }
1170 }