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                                           (other.IsZeroInteger && other is IntConstant));
 162
 163                                 if (need_check &&
 164                                     !Convert.ImplicitConversionExists (ec, match, other.Type)) {
 165                                         Convert.Error_CannotImplicitConversion (loc, match.Type, other.Type);
 166                                         left = null;
 167                                         right = null;
 168                                         return;
 169                                 }
 170
 171                                 if (left is EnumConstant)
 172                                         left = ((EnumConstant) left).Child;
 173                                 if (right is EnumConstant)
 174                                         right = ((EnumConstant) right).Child;
 175
 176                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 177                                 return;
 178
 179                         } else {
 180                                 //
 181                                 // Force conversions to int32
 182                                 //
 183                                 if (!(left is IntConstant))
 184                                         left = left.ToInt (loc);
 185                                 if (!(right is IntConstant))
 186                                         right = right.ToInt (loc);
 187                         }
 188                         return;
 189                 }
 190
 191                 static void Error_CompileTimeOverflow (Location loc)
 192                 {
 193                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 194                 }
 195
 196                 /// <summary>
 197                 ///   Constant expression folder for binary operations.
 198                 ///
 199                 ///   Returns null if the expression can not be folded.
 200                 /// </summary>
 201                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 202                                                      Constant left, Constant right, Location loc)
 203                 {
 204                         Type lt = left.Type;
 205                         Type rt = right.Type;
 206                         Type result_type = null;
 207                         bool bool_res;
 208
 209                         //
 210                         // Enumerator folding
 211                         //
 212                         if (rt == lt && left is EnumConstant)
 213                                 result_type = lt;
 214
 215                         //
 216                         // During an enum evaluation, we need to unwrap enumerations
 217                         //
 218                         if (ec.InEnumContext){
 219                                 if (left is EnumConstant)
 220                                         left = ((EnumConstant) left).Child;
 221
 222                                 if (right is EnumConstant)
 223                                         right = ((EnumConstant) right).Child;
 224                         }
 225
 226                         Type wrap_as;
 227                         Constant result = null;
 228                         switch (oper){
 229                         case Binary.Operator.BitwiseOr:
 230                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 231                                 if (left == null || right == null)
 232                                         return null;
 233
 234                                 if (left is IntConstant){
 235                                         IntConstant v;
 236                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 237
 238                                         v = new IntConstant (res);
 239                                         if (result_type == null)
 240                                                 return v;
 241                                         else
 242                                                 return new EnumConstant (v, result_type);
 243                                 } else if (left is UIntConstant){
 244                                         UIntConstant v;
 245                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 246
 247                                         v = new UIntConstant (res);
 248                                         if (result_type == null)
 249                                                 return v;
 250                                         else
 251                                                 return new EnumConstant (v, result_type);
 252                                 } else if (left is LongConstant){
 253                                         LongConstant v;
 254                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 255
 256                                         v = new LongConstant (res);
 257                                         if (result_type == null)
 258                                                 return v;
 259                                         else
 260                                                 return new EnumConstant (v, result_type);
 261                                 } else if (left is ULongConstant){
 262                                         ULongConstant v;
 263                                         ulong res = ((ULongConstant)left).Value |
 264                                                 ((ULongConstant)right).Value;
 265
 266                                         v = new ULongConstant (res);
 267                                         if (result_type == null)
 268                                                 return v;
 269                                         else
 270                                                 return new EnumConstant (v, result_type);
 271                                 } else if (left is UShortConstant){
 272                                         UShortConstant v;
 273                                         ushort res = (ushort) (((UShortConstant)left).Value |
 274                                                                ((UShortConstant)right).Value);
 275
 276                                         v = new UShortConstant (res);
 277                                         if (result_type == null)
 278                                                 return v;
 279                                         else
 280                                                 return new EnumConstant (v, result_type);
 281                                 } else if (left is ShortConstant){
 282                                         ShortConstant v;
 283                                         short res = (short) (((ShortConstant)left).Value |
 284                                                              ((ShortConstant)right).Value);
 285
 286                                         v = new ShortConstant (res);
 287                                         if (result_type == null)
 288                                                 return v;
 289                                         else
 290                                                 return new EnumConstant (v, result_type);
 291                                 }
 292                                 break;
 293
 294                         case Binary.Operator.BitwiseAnd:
 295                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 296                                 if (left == null || right == null)
 297                                         return null;
 298
 299                                 if (left is IntConstant){
 300                                         IntConstant v;
 301                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 302
 303                                         v = new IntConstant (res);
 304                                         if (result_type == null)
 305                                                 return v;
 306                                         else
 307                                                 return new EnumConstant (v, result_type);
 308                                 } else if (left is UIntConstant){
 309                                         UIntConstant v;
 310                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 311
 312                                         v = new UIntConstant (res);
 313                                         if (result_type == null)
 314                                                 return v;
 315                                         else
 316                                                 return new EnumConstant (v, result_type);
 317                                 } else if (left is LongConstant){
 318                                         LongConstant v;
 319                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 320
 321                                         v = new LongConstant (res);
 322                                         if (result_type == null)
 323                                                 return v;
 324                                         else
 325                                                 return new EnumConstant (v, result_type);
 326                                 } else if (left is ULongConstant){
 327                                         ULongConstant v;
 328                                         ulong res = ((ULongConstant)left).Value &
 329                                                 ((ULongConstant)right).Value;
 330
 331                                         v = new ULongConstant (res);
 332                                         if (result_type == null)
 333                                                 return v;
 334                                         else
 335                                                 return new EnumConstant (v, result_type);
 336                                 } else if (left is UShortConstant){
 337                                         UShortConstant v;
 338                                         ushort res = (ushort) (((UShortConstant)left).Value &
 339                                                                ((UShortConstant)right).Value);
 340
 341                                         v = new UShortConstant (res);
 342                                         if (result_type == null)
 343                                                 return v;
 344                                         else
 345                                                 return new EnumConstant (v, result_type);
 346                                 } else if (left is ShortConstant){
 347                                         ShortConstant v;
 348                                         short res = (short) (((ShortConstant)left).Value &
 349                                                              ((ShortConstant)right).Value);
 350
 351                                         v = new ShortConstant (res);
 352                                         if (result_type == null)
 353                                                 return v;
 354                                         else
 355                                                 return new EnumConstant (v, result_type);
 356                                 }
 357                                 break;
 358
 359                         case Binary.Operator.ExclusiveOr:
 360                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 361                                 if (left == null || right == null)
 362                                         return null;
 363
 364                                 if (left is IntConstant){
 365                                         IntConstant v;
 366                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 367
 368                                         v = new IntConstant (res);
 369                                         if (result_type == null)
 370                                                 return v;
 371                                         else
 372                                                 return new EnumConstant (v, result_type);
 373                                 } else if (left is UIntConstant){
 374                                         UIntConstant v;
 375                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 376
 377                                         v = new UIntConstant (res);
 378                                         if (result_type == null)
 379                                                 return v;
 380                                         else
 381                                                 return new EnumConstant (v, result_type);
 382                                 } else if (left is LongConstant){
 383                                         LongConstant v;
 384                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 385
 386                                         v = new LongConstant (res);
 387                                         if (result_type == null)
 388                                                 return v;
 389                                         else
 390                                                 return new EnumConstant (v, result_type);
 391                                 } else if (left is ULongConstant){
 392                                         ULongConstant v;
 393                                         ulong res = ((ULongConstant)left).Value ^
 394                                                 ((ULongConstant)right).Value;
 395
 396                                         v = new ULongConstant (res);
 397                                         if (result_type == null)
 398                                                 return v;
 399                                         else
 400                                                 return new EnumConstant (v, result_type);
 401                                 } else if (left is UShortConstant){
 402                                         UShortConstant v;
 403                                         ushort res = (ushort) (((UShortConstant)left).Value ^
 404                                                                ((UShortConstant)right).Value);
 405
 406                                         v = new UShortConstant (res);
 407                                         if (result_type == null)
 408                                                 return v;
 409                                         else
 410                                                 return new EnumConstant (v, result_type);
 411                                 } else if (left is ShortConstant){
 412                                         ShortConstant v;
 413                                         short res = (short)(((ShortConstant)left).Value ^
 414                                                             ((ShortConstant)right).Value);
 415
 416                                         v = new ShortConstant (res);
 417                                         if (result_type == null)
 418                                                 return v;
 419                                         else
 420                                                 return new EnumConstant (v, result_type);
 421                                 }
 422                                 break;
 423
 424                         case Binary.Operator.Addition:
 425                                 bool left_is_string = left is StringConstant;
 426                                 bool right_is_string = right is StringConstant;
 427
 428                                 //
 429                                 // If both sides are strings, then concatenate, if
 430                                 // one is a string, and the other is not, then defer
 431                                 // to runtime concatenation
 432                                 //
 433                                 wrap_as = null;
 434                                 if (left_is_string || right_is_string){
 435                                         if (left_is_string && right_is_string)
 436                                                 return new StringConstant (
 437                                                         ((StringConstant) left).Value +
 438                                                         ((StringConstant) right).Value);
 439
 440                                         return null;
 441                                 }
 442
 443                                 //
 444                                 // handle "E operator + (E x, U y)"
 445                                 // handle "E operator + (Y y, E x)"
 446                                 //
 447                                 // note that E operator + (E x, E y) is invalid
 448                                 //
 449                                 if (left is EnumConstant){
 450                                         if (right is EnumConstant){
 451                                                 return null;
 452                                         }
 453                                         if (((EnumConstant) left).Child.Type != right.Type)
 454                                                 return null;
 455
 456                                         wrap_as = left.Type;
 457                                 } else if (right is EnumConstant){
 458                                         if (((EnumConstant) right).Child.Type != left.Type)
 459                                                 return null;
 460                                         wrap_as = right.Type;
 461                                 }
 462
 463                                 result = null;
 464                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 465                                 if (left == null || right == null)
 466                                         return null;
 467
 468                                 try {
 469                                         if (left is DoubleConstant){
 470                                                 double res;
 471
 472                                                 if (ec.ConstantCheckState)
 473                                                         res = checked (((DoubleConstant) left).Value +
 474                                                                        ((DoubleConstant) right).Value);
 475                                                 else
 476                                                         res = unchecked (((DoubleConstant) left).Value +
 477                                                                          ((DoubleConstant) right).Value);
 478
 479                                                 result = new DoubleConstant (res);
 480                                         } else if (left is FloatConstant){
 481                                                 float res;
 482
 483                                                 if (ec.ConstantCheckState)
 484                                                         res = checked (((FloatConstant) left).Value +
 485                                                                        ((FloatConstant) right).Value);
 486                                                 else
 487                                                         res = unchecked (((FloatConstant) left).Value +
 488                                                                          ((FloatConstant) right).Value);
 489
 490                                                 result = new FloatConstant (res);
 491                                         } else if (left is ULongConstant){
 492                                                 ulong res;
 493
 494                                                 if (ec.ConstantCheckState)
 495                                                         res = checked (((ULongConstant) left).Value +
 496                                                                        ((ULongConstant) right).Value);
 497                                                 else
 498                                                         res = unchecked (((ULongConstant) left).Value +
 499                                                                          ((ULongConstant) right).Value);
 500
 501                                                 result = new ULongConstant (res);
 502                                         } else if (left is LongConstant){
 503                                                 long res;
 504
 505                                                 if (ec.ConstantCheckState)
 506                                                         res = checked (((LongConstant) left).Value +
 507                                                                        ((LongConstant) right).Value);
 508                                                 else
 509                                                         res = unchecked (((LongConstant) left).Value +
 510                                                                          ((LongConstant) right).Value);
 511
 512                                                 result = new LongConstant (res);
 513                                         } else if (left is UIntConstant){
 514                                                 uint res;
 515
 516                                                 if (ec.ConstantCheckState)
 517                                                         res = checked (((UIntConstant) left).Value +
 518                                                                        ((UIntConstant) right).Value);
 519                                                 else
 520                                                         res = unchecked (((UIntConstant) left).Value +
 521                                                                          ((UIntConstant) right).Value);
 522
 523                                                 result = new UIntConstant (res);
 524                                         } else if (left is IntConstant){
 525                                                 int res;
 526
 527                                                 if (ec.ConstantCheckState)
 528                                                         res = checked (((IntConstant) left).Value +
 529                                                                        ((IntConstant) right).Value);
 530                                                 else
 531                                                         res = unchecked (((IntConstant) left).Value +
 532                                                                          ((IntConstant) right).Value);
 533
 534                                                 result = new IntConstant (res);
 535                                         } else if (left is DecimalConstant) {
 536                                                 decimal res;
 537
 538                                                 if (ec.ConstantCheckState)
 539                                                         res = checked (((DecimalConstant) left).Value +
 540                                                                 ((DecimalConstant) right).Value);
 541                                                 else
 542                                                         res = unchecked (((DecimalConstant) left).Value +
 543                                                                 ((DecimalConstant) right).Value);
 544
 545                                                 result = new DecimalConstant (res);
 546                                         } else {
 547                                                 throw new Exception ( "Unexepected addition input: " + left);
 548                                         }
 549                                 } catch (OverflowException){
 550                                         Error_CompileTimeOverflow (loc);
 551                                 }
 552
 553                                 if (wrap_as != null)
 554                                         return new EnumConstant (result, wrap_as);
 555                                 else
 556                                         return result;
 557
 558                         case Binary.Operator.Subtraction:
 559                                 //
 560                                 // handle "E operator - (E x, U y)"
 561                                 // handle "E operator - (Y y, E x)"
 562                                 // handle "U operator - (E x, E y)"
 563                                 //
 564                                 wrap_as = null;
 565                                 if (left is EnumConstant){
 566                                         if (right is EnumConstant){
 567                                                 if (left.Type == right.Type)
 568                                                         wrap_as = TypeManager.EnumToUnderlying (left.Type);
 569                                                 else
 570                                                         return null;
 571                                         }
 572                                         if (((EnumConstant) left).Child.Type != right.Type)
 573                                                 return null;
 574
 575                                         wrap_as = left.Type;
 576                                 } else if (right is EnumConstant){
 577                                         if (((EnumConstant) right).Child.Type != left.Type)
 578                                                 return null;
 579                                         wrap_as = right.Type;
 580                                 }
 581
 582                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 583                                 if (left == null || right == null)
 584                                         return null;
 585
 586                                 try {
 587                                         if (left is DoubleConstant){
 588                                                 double res;
 589
 590                                                 if (ec.ConstantCheckState)
 591                                                         res = checked (((DoubleConstant) left).Value -
 592                                                                        ((DoubleConstant) right).Value);
 593                                                 else
 594                                                         res = unchecked (((DoubleConstant) left).Value -
 595                                                                          ((DoubleConstant) right).Value);
 596
 597                                                 result = new DoubleConstant (res);
 598                                         } else if (left is FloatConstant){
 599                                                 float res;
 600
 601                                                 if (ec.ConstantCheckState)
 602                                                         res = checked (((FloatConstant) left).Value -
 603                                                                        ((FloatConstant) right).Value);
 604                                                 else
 605                                                         res = unchecked (((FloatConstant) left).Value -
 606                                                                          ((FloatConstant) right).Value);
 607
 608                                                 result = new FloatConstant (res);
 609                                         } else if (left is ULongConstant){
 610                                                 ulong res;
 611
 612                                                 if (ec.ConstantCheckState)
 613                                                         res = checked (((ULongConstant) left).Value -
 614                                                                        ((ULongConstant) right).Value);
 615                                                 else
 616                                                         res = unchecked (((ULongConstant) left).Value -
 617                                                                          ((ULongConstant) right).Value);
 618
 619                                                 result = new ULongConstant (res);
 620                                         } else if (left is LongConstant){
 621                                                 long res;
 622
 623                                                 if (ec.ConstantCheckState)
 624                                                         res = checked (((LongConstant) left).Value -
 625                                                                        ((LongConstant) right).Value);
 626                                                 else
 627                                                         res = unchecked (((LongConstant) left).Value -
 628                                                                          ((LongConstant) right).Value);
 629
 630                                                 result = new LongConstant (res);
 631                                         } else if (left is UIntConstant){
 632                                                 uint res;
 633
 634                                                 if (ec.ConstantCheckState)
 635                                                         res = checked (((UIntConstant) left).Value -
 636                                                                        ((UIntConstant) right).Value);
 637                                                 else
 638                                                         res = unchecked (((UIntConstant) left).Value -
 639                                                                          ((UIntConstant) right).Value);
 640
 641                                                 result = new UIntConstant (res);
 642                                         } else if (left is IntConstant){
 643                                                 int res;
 644
 645                                                 if (ec.ConstantCheckState)
 646                                                         res = checked (((IntConstant) left).Value -
 647                                                                        ((IntConstant) right).Value);
 648                                                 else
 649                                                         res = unchecked (((IntConstant) left).Value -
 650                                                                          ((IntConstant) right).Value);
 651
 652                                                 result = new IntConstant (res);
 653                                         } else if (left is DecimalConstant) {
 654                                                 decimal res;
 655
 656                                                 if (ec.ConstantCheckState)
 657                                                         res = checked (((DecimalConstant) left).Value -
 658                                                                 ((DecimalConstant) right).Value);
 659                                                 else
 660                                                         res = unchecked (((DecimalConstant) left).Value -
 661                                                                 ((DecimalConstant) right).Value);
 662
 663                                                 return new DecimalConstant (res);
 664                                         } else {
 665                                                 throw new Exception ( "Unexepected subtraction input: " + left);
 666                                         }
 667                                 } catch (OverflowException){
 668                                         Error_CompileTimeOverflow (loc);
 669                                 }
 670                                 if (wrap_as != null)
 671                                         return new EnumConstant (result, wrap_as);
 672                                 else
 673                                         return result;
 674
 675                         case Binary.Operator.Multiply:
 676                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 677                                 if (left == null || right == null)
 678                                         return null;
 679
 680                                 try {
 681                                         if (left is DoubleConstant){
 682                                                 double res;
 683
 684                                                 if (ec.ConstantCheckState)
 685                                                         res = checked (((DoubleConstant) left).Value *
 686                                                                 ((DoubleConstant) right).Value);
 687                                                 else
 688                                                         res = unchecked (((DoubleConstant) left).Value *
 689                                                                 ((DoubleConstant) right).Value);
 690
 691                                                 return new DoubleConstant (res);
 692                                         } else if (left is FloatConstant){
 693                                                 float res;
 694
 695                                                 if (ec.ConstantCheckState)
 696                                                         res = checked (((FloatConstant) left).Value *
 697                                                                 ((FloatConstant) right).Value);
 698                                                 else
 699                                                         res = unchecked (((FloatConstant) left).Value *
 700                                                                 ((FloatConstant) right).Value);
 701
 702                                                 return new FloatConstant (res);
 703                                         } else if (left is ULongConstant){
 704                                                 ulong res;
 705
 706                                                 if (ec.ConstantCheckState)
 707                                                         res = checked (((ULongConstant) left).Value *
 708                                                                 ((ULongConstant) right).Value);
 709                                                 else
 710                                                         res = unchecked (((ULongConstant) left).Value *
 711                                                                 ((ULongConstant) right).Value);
 712
 713                                                 return new ULongConstant (res);
 714                                         } else if (left is LongConstant){
 715                                                 long res;
 716
 717                                                 if (ec.ConstantCheckState)
 718                                                         res = checked (((LongConstant) left).Value *
 719                                                                 ((LongConstant) right).Value);
 720                                                 else
 721                                                         res = unchecked (((LongConstant) left).Value *
 722                                                                 ((LongConstant) right).Value);
 723
 724                                                 return new LongConstant (res);
 725                                         } else if (left is UIntConstant){
 726                                                 uint res;
 727
 728                                                 if (ec.ConstantCheckState)
 729                                                         res = checked (((UIntConstant) left).Value *
 730                                                                 ((UIntConstant) right).Value);
 731                                                 else
 732                                                         res = unchecked (((UIntConstant) left).Value *
 733                                                                 ((UIntConstant) right).Value);
 734
 735                                                 return new UIntConstant (res);
 736                                         } else if (left is IntConstant){
 737                                                 int res;
 738
 739                                                 if (ec.ConstantCheckState)
 740                                                         res = checked (((IntConstant) left).Value *
 741                                                                 ((IntConstant) right).Value);
 742                                                 else
 743                                                         res = unchecked (((IntConstant) left).Value *
 744                                                                 ((IntConstant) right).Value);
 745
 746                                                 return new IntConstant (res);
 747                                         } else if (left is DecimalConstant) {
 748                                                 decimal res;
 749
 750                                                 if (ec.ConstantCheckState)
 751                                                         res = checked (((DecimalConstant) left).Value *
 752                                                                 ((DecimalConstant) right).Value);
 753                                                 else
 754                                                         res = unchecked (((DecimalConstant) left).Value *
 755                                                                 ((DecimalConstant) right).Value);
 756
 757                                                 return new DecimalConstant (res);
 758                                         } else {
 759                                                 throw new Exception ( "Unexepected multiply input: " + left);
 760                                         }
 761                                 } catch (OverflowException){
 762                                         Error_CompileTimeOverflow (loc);
 763                                 }
 764                                 break;
 765
 766                         case Binary.Operator.Division:
 767                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 768                                 if (left == null || right == null)
 769                                         return null;
 770
 771                                 try {
 772                                         if (left is DoubleConstant){
 773                                                 double res;
 774
 775                                                 if (ec.ConstantCheckState)
 776                                                         res = checked (((DoubleConstant) left).Value /
 777                                                                 ((DoubleConstant) right).Value);
 778                                                 else
 779                                                         res = unchecked (((DoubleConstant) left).Value /
 780                                                                 ((DoubleConstant) right).Value);
 781
 782                                                 return new DoubleConstant (res);
 783                                         } else if (left is FloatConstant){
 784                                                 float res;
 785
 786                                                 if (ec.ConstantCheckState)
 787                                                         res = checked (((FloatConstant) left).Value /
 788                                                                 ((FloatConstant) right).Value);
 789                                                 else
 790                                                         res = unchecked (((FloatConstant) left).Value /
 791                                                                 ((FloatConstant) right).Value);
 792
 793                                                 return new FloatConstant (res);
 794                                         } else if (left is ULongConstant){
 795                                                 ulong res;
 796
 797                                                 if (ec.ConstantCheckState)
 798                                                         res = checked (((ULongConstant) left).Value /
 799                                                                 ((ULongConstant) right).Value);
 800                                                 else
 801                                                         res = unchecked (((ULongConstant) left).Value /
 802                                                                 ((ULongConstant) right).Value);
 803
 804                                                 return new ULongConstant (res);
 805                                         } else if (left is LongConstant){
 806                                                 long res;
 807
 808                                                 if (ec.ConstantCheckState)
 809                                                         res = checked (((LongConstant) left).Value /
 810                                                                 ((LongConstant) right).Value);
 811                                                 else
 812                                                         res = unchecked (((LongConstant) left).Value /
 813                                                                 ((LongConstant) right).Value);
 814
 815                                                 return new LongConstant (res);
 816                                         } else if (left is UIntConstant){
 817                                                 uint res;
 818
 819                                                 if (ec.ConstantCheckState)
 820                                                         res = checked (((UIntConstant) left).Value /
 821                                                                 ((UIntConstant) right).Value);
 822                                                 else
 823                                                         res = unchecked (((UIntConstant) left).Value /
 824                                                                 ((UIntConstant) right).Value);
 825
 826                                                 return new UIntConstant (res);
 827                                         } else if (left is IntConstant){
 828                                                 int res;
 829
 830                                                 if (ec.ConstantCheckState)
 831                                                         res = checked (((IntConstant) left).Value /
 832                                                                 ((IntConstant) right).Value);
 833                                                 else
 834                                                         res = unchecked (((IntConstant) left).Value /
 835                                                                 ((IntConstant) right).Value);
 836
 837                                                 return new IntConstant (res);
 838                                         } else if (left is DecimalConstant) {
 839                                                 decimal res;
 840
 841                                                 if (ec.ConstantCheckState)
 842                                                         res = checked (((DecimalConstant) left).Value /
 843                                                                 ((DecimalConstant) right).Value);
 844                                                 else
 845                                                         res = unchecked (((DecimalConstant) left).Value /
 846                                                                 ((DecimalConstant) right).Value);
 847
 848                                                 return new DecimalConstant (res);
 849                                         } else {
 850                                                 throw new Exception ( "Unexepected division input: " + left);
 851                                         }
 852                                 } catch (OverflowException){
 853                                         Error_CompileTimeOverflow (loc);
 854
 855                                 } catch (DivideByZeroException) {
 856                                         Report.Error (020, loc, "Division by constant zero");
 857                                 }
 858
 859                                 break;
 860
 861                         case Binary.Operator.Modulus:
 862                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 863                                 if (left == null || right == null)
 864                                         return null;
 865
 866                                 try {
 867                                         if (left is DoubleConstant){
 868                                                 double res;
 869
 870                                                 if (ec.ConstantCheckState)
 871                                                         res = checked (((DoubleConstant) left).Value %
 872                                                                        ((DoubleConstant) right).Value);
 873                                                 else
 874                                                         res = unchecked (((DoubleConstant) left).Value %
 875                                                                          ((DoubleConstant) right).Value);
 876
 877                                                 return new DoubleConstant (res);
 878                                         } else if (left is FloatConstant){
 879                                                 float res;
 880
 881                                                 if (ec.ConstantCheckState)
 882                                                         res = checked (((FloatConstant) left).Value %
 883                                                                        ((FloatConstant) right).Value);
 884                                                 else
 885                                                         res = unchecked (((FloatConstant) left).Value %
 886                                                                          ((FloatConstant) right).Value);
 887
 888                                                 return new FloatConstant (res);
 889                                         } else if (left is ULongConstant){
 890                                                 ulong res;
 891
 892                                                 if (ec.ConstantCheckState)
 893                                                         res = checked (((ULongConstant) left).Value %
 894                                                                        ((ULongConstant) right).Value);
 895                                                 else
 896                                                         res = unchecked (((ULongConstant) left).Value %
 897                                                                          ((ULongConstant) right).Value);
 898
 899                                                 return new ULongConstant (res);
 900                                         } else if (left is LongConstant){
 901                                                 long res;
 902
 903                                                 if (ec.ConstantCheckState)
 904                                                         res = checked (((LongConstant) left).Value %
 905                                                                        ((LongConstant) right).Value);
 906                                                 else
 907                                                         res = unchecked (((LongConstant) left).Value %
 908                                                                          ((LongConstant) right).Value);
 909
 910                                                 return new LongConstant (res);
 911                                         } else if (left is UIntConstant){
 912                                                 uint res;
 913
 914                                                 if (ec.ConstantCheckState)
 915                                                         res = checked (((UIntConstant) left).Value %
 916                                                                        ((UIntConstant) right).Value);
 917                                                 else
 918                                                         res = unchecked (((UIntConstant) left).Value %
 919                                                                          ((UIntConstant) right).Value);
 920
 921                                                 return new UIntConstant (res);
 922                                         } else if (left is IntConstant){
 923                                                 int res;
 924
 925                                                 if (ec.ConstantCheckState)
 926                                                         res = checked (((IntConstant) left).Value %
 927                                                                        ((IntConstant) right).Value);
 928                                                 else
 929                                                         res = unchecked (((IntConstant) left).Value %
 930                                                                          ((IntConstant) right).Value);
 931
 932                                                 return new IntConstant (res);
 933                                         } else {
 934                                                 throw new Exception ( "Unexepected modulus input: " + left);
 935                                         }
 936                                 } catch (DivideByZeroException){
 937                                         Report.Error (020, loc, "Division by constant zero");
 938                                 } catch (OverflowException){
 939                                         Error_CompileTimeOverflow (loc);
 940                                 }
 941                                 break;
 942
 943                                 //
 944                                 // There is no overflow checking on left shift
 945                                 //
 946                         case Binary.Operator.LeftShift:
 947                                 IntConstant ic = right.ToInt (loc);
 948                                 if (ic == null){
 949                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 950                                         return null;
 951                                 }
 952                                 int lshift_val = ic.Value;
 953
 954                                 IntConstant lic;
 955                                 if ((lic = left.ConvertToInt ()) != null)
 956                                         return new IntConstant (lic.Value << lshift_val);
 957
 958                                 UIntConstant luic;
 959                                 if ((luic = left.ConvertToUInt ()) != null)
 960                                         return new UIntConstant (luic.Value << lshift_val);
 961
 962                                 LongConstant llc;
 963                                 if ((llc = left.ConvertToLong ()) != null)
 964                                         return new LongConstant (llc.Value << lshift_val);
 965
 966                                 ULongConstant lulc;
 967                                 if ((lulc = left.ConvertToULong ()) != null)
 968                                         return new ULongConstant (lulc.Value << lshift_val);
 969
 970                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 971                                 break;
 972
 973                                 //
 974                                 // There is no overflow checking on right shift
 975                                 //
 976                         case Binary.Operator.RightShift:
 977                                 IntConstant sic = right.ToInt (loc);
 978                                 if (sic == null){
 979                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 980                                         return null;
 981                                 }
 982                                 int rshift_val = sic.Value;
 983
 984                                 IntConstant ric;
 985                                 if ((ric = left.ConvertToInt ()) != null)
 986                                         return new IntConstant (ric.Value >> rshift_val);
 987
 988                                 UIntConstant ruic;
 989                                 if ((ruic = left.ConvertToUInt ()) != null)
 990                                         return new UIntConstant (ruic.Value >> rshift_val);
 991
 992                                 LongConstant rlc;
 993                                 if ((rlc = left.ConvertToLong ()) != null)
 994                                         return new LongConstant (rlc.Value >> rshift_val);
 995
 996                                 ULongConstant rulc;
 997                                 if ((rulc = left.ConvertToULong ()) != null)
 998                                         return new ULongConstant (rulc.Value >> rshift_val);
 999
1000                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
1001                                 break;
1002
1003                         case Binary.Operator.LogicalAnd:
1004                                 if (left is BoolConstant && right is BoolConstant){
1005                                         return new BoolConstant (
1006                                                 ((BoolConstant) left).Value &&
1007                                                 ((BoolConstant) right).Value);
1008                                 }
1009                                 break;
1010
1011                         case Binary.Operator.LogicalOr:
1012                                 if (left is BoolConstant && right is BoolConstant){
1013                                         return new BoolConstant (
1014                                                 ((BoolConstant) left).Value ||
1015                                                 ((BoolConstant) right).Value);
1016                                 }
1017                                 break;
1018
1019                         case Binary.Operator.Equality:
1020                                 if (left is BoolConstant && right is BoolConstant){
1021                                         return new BoolConstant (
1022                                                 ((BoolConstant) left).Value ==
1023                                                 ((BoolConstant) right).Value);
1024
1025                                 }
1026                                 if (left is NullLiteral){
1027                                         if (right is NullLiteral)
1028                                                 return new BoolConstant (true);
1029                                         else if (right is StringConstant)
1030                                                 return new BoolConstant (
1031                                                         ((StringConstant) right).Value == null);
1032                                 } else if (right is NullLiteral){
1033                                         if (left is NullLiteral)
1034                                                 return new BoolConstant (true);
1035                                         else if (left is StringConstant)
1036                                                 return new BoolConstant (
1037                                                         ((StringConstant) left).Value == null);
1038                                 }
1039                                 if (left is StringConstant && right is StringConstant){
1040                                         return new BoolConstant (
1041                                                 ((StringConstant) left).Value ==
1042                                                 ((StringConstant) right).Value);
1043
1044                                 }
1045
1046                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1047                                 if (left == null || right == null)
1048                                         return null;
1049
1050                                 bool_res = false;
1051                                 if (left is DoubleConstant)
1052                                         bool_res = ((DoubleConstant) left).Value ==
1053                                                 ((DoubleConstant) right).Value;
1054                                 else if (left is FloatConstant)
1055                                         bool_res = ((FloatConstant) left).Value ==
1056                                                 ((FloatConstant) right).Value;
1057                                 else if (left is ULongConstant)
1058                                         bool_res = ((ULongConstant) left).Value ==
1059                                                 ((ULongConstant) right).Value;
1060                                 else if (left is LongConstant)
1061                                         bool_res = ((LongConstant) left).Value ==
1062                                                 ((LongConstant) right).Value;
1063                                 else if (left is UIntConstant)
1064                                         bool_res = ((UIntConstant) left).Value ==
1065                                                 ((UIntConstant) right).Value;
1066                                 else if (left is IntConstant)
1067                                         bool_res = ((IntConstant) left).Value ==
1068                                                 ((IntConstant) right).Value;
1069                                 else
1070                                         return null;
1071
1072                                 return new BoolConstant (bool_res);
1073
1074                         case Binary.Operator.Inequality:
1075                                 if (left is BoolConstant && right is BoolConstant){
1076                                         return new BoolConstant (
1077                                                 ((BoolConstant) left).Value !=
1078                                                 ((BoolConstant) right).Value);
1079                                 }
1080                                 if (left is NullLiteral){
1081                                         if (right is NullLiteral)
1082                                                 return new BoolConstant (false);
1083                                         else if (right is StringConstant)
1084                                                 return new BoolConstant (
1085                                                         ((StringConstant) right).Value != null);
1086                                 } else if (right is NullLiteral){
1087                                         if (left is NullLiteral)
1088                                                 return new BoolConstant (false);
1089                                         else if (left is StringConstant)
1090                                                 return new BoolConstant (
1091                                                         ((StringConstant) left).Value != null);
1092                                 }
1093                                 if (left is StringConstant && right is StringConstant){
1094                                         return new BoolConstant (
1095                                                 ((StringConstant) left).Value !=
1096                                                 ((StringConstant) right).Value);
1097
1098                                 }
1099                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1100                                 if (left == null || right == null)
1101                                         return null;
1102
1103                                 bool_res = false;
1104                                 if (left is DoubleConstant)
1105                                         bool_res = ((DoubleConstant) left).Value !=
1106                                                 ((DoubleConstant) right).Value;
1107                                 else if (left is FloatConstant)
1108                                         bool_res = ((FloatConstant) left).Value !=
1109                                                 ((FloatConstant) right).Value;
1110                                 else if (left is ULongConstant)
1111                                         bool_res = ((ULongConstant) left).Value !=
1112                                                 ((ULongConstant) right).Value;
1113                                 else if (left is LongConstant)
1114                                         bool_res = ((LongConstant) left).Value !=
1115                                                 ((LongConstant) right).Value;
1116                                 else if (left is UIntConstant)
1117                                         bool_res = ((UIntConstant) left).Value !=
1118                                                 ((UIntConstant) right).Value;
1119                                 else if (left is IntConstant)
1120                                         bool_res = ((IntConstant) left).Value !=
1121                                                 ((IntConstant) right).Value;
1122                                 else
1123                                         return null;
1124
1125                                 return new BoolConstant (bool_res);
1126
1127                         case Binary.Operator.LessThan:
1128                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1129                                 if (left == null || right == null)
1130                                         return null;
1131
1132                                 bool_res = false;
1133                                 if (left is DoubleConstant)
1134                                         bool_res = ((DoubleConstant) left).Value <
1135                                                 ((DoubleConstant) right).Value;
1136                                 else if (left is FloatConstant)
1137                                         bool_res = ((FloatConstant) left).Value <
1138                                                 ((FloatConstant) right).Value;
1139                                 else if (left is ULongConstant)
1140                                         bool_res = ((ULongConstant) left).Value <
1141                                                 ((ULongConstant) right).Value;
1142                                 else if (left is LongConstant)
1143                                         bool_res = ((LongConstant) left).Value <
1144                                                 ((LongConstant) right).Value;
1145                                 else if (left is UIntConstant)
1146                                         bool_res = ((UIntConstant) left).Value <
1147                                                 ((UIntConstant) right).Value;
1148                                 else if (left is IntConstant)
1149                                         bool_res = ((IntConstant) left).Value <
1150                                                 ((IntConstant) right).Value;
1151                                 else
1152                                         return null;
1153
1154                                 return new BoolConstant (bool_res);
1155
1156                         case Binary.Operator.GreaterThan:
1157                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1158                                 if (left == null || right == null)
1159                                         return null;
1160
1161                                 bool_res = false;
1162                                 if (left is DoubleConstant)
1163                                         bool_res = ((DoubleConstant) left).Value >
1164                                                 ((DoubleConstant) right).Value;
1165                                 else if (left is FloatConstant)
1166                                         bool_res = ((FloatConstant) left).Value >
1167                                                 ((FloatConstant) right).Value;
1168                                 else if (left is ULongConstant)
1169                                         bool_res = ((ULongConstant) left).Value >
1170                                                 ((ULongConstant) right).Value;
1171                                 else if (left is LongConstant)
1172                                         bool_res = ((LongConstant) left).Value >
1173                                                 ((LongConstant) right).Value;
1174                                 else if (left is UIntConstant)
1175                                         bool_res = ((UIntConstant) left).Value >
1176                                                 ((UIntConstant) right).Value;
1177                                 else if (left is IntConstant)
1178                                         bool_res = ((IntConstant) left).Value >
1179                                                 ((IntConstant) right).Value;
1180                                 else
1181                                         return null;
1182
1183                                 return new BoolConstant (bool_res);
1184
1185                         case Binary.Operator.GreaterThanOrEqual:
1186                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1187                                 if (left == null || right == null)
1188                                         return null;
1189
1190                                 bool_res = false;
1191                                 if (left is DoubleConstant)
1192                                         bool_res = ((DoubleConstant) left).Value >=
1193                                                 ((DoubleConstant) right).Value;
1194                                 else if (left is FloatConstant)
1195                                         bool_res = ((FloatConstant) left).Value >=
1196                                                 ((FloatConstant) right).Value;
1197                                 else if (left is ULongConstant)
1198                                         bool_res = ((ULongConstant) left).Value >=
1199                                                 ((ULongConstant) right).Value;
1200                                 else if (left is LongConstant)
1201                                         bool_res = ((LongConstant) left).Value >=
1202                                                 ((LongConstant) right).Value;
1203                                 else if (left is UIntConstant)
1204                                         bool_res = ((UIntConstant) left).Value >=
1205                                                 ((UIntConstant) right).Value;
1206                                 else if (left is IntConstant)
1207                                         bool_res = ((IntConstant) left).Value >=
1208                                                 ((IntConstant) right).Value;
1209                                 else
1210                                         return null;
1211
1212                                 return new BoolConstant (bool_res);
1213
1214                         case Binary.Operator.LessThanOrEqual:
1215                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1216                                 if (left == null || right == null)
1217                                         return null;
1218
1219                                 bool_res = false;
1220                                 if (left is DoubleConstant)
1221                                         bool_res = ((DoubleConstant) left).Value <=
1222                                                 ((DoubleConstant) right).Value;
1223                                 else if (left is FloatConstant)
1224                                         bool_res = ((FloatConstant) left).Value <=
1225                                                 ((FloatConstant) right).Value;
1226                                 else if (left is ULongConstant)
1227                                         bool_res = ((ULongConstant) left).Value <=
1228                                                 ((ULongConstant) right).Value;
1229                                 else if (left is LongConstant)
1230                                         bool_res = ((LongConstant) left).Value <=
1231                                                 ((LongConstant) right).Value;
1232                                 else if (left is UIntConstant)
1233                                         bool_res = ((UIntConstant) left).Value <=
1234                                                 ((UIntConstant) right).Value;
1235                                 else if (left is IntConstant)
1236                                         bool_res = ((IntConstant) left).Value <=
1237                                                 ((IntConstant) right).Value;
1238                                 else
1239                                         return null;
1240
1241                                 return new BoolConstant (bool_res);
1242                         }
1243
1244                         return null;
1245                 }
1246         }
1247 }