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, ic.Location);
 122                                                 else
 123                                                         right = new UIntConstant ((uint) ic.Value, ic.Location);
 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                                 if (left is EnumConstant)
 145                                         left = ((EnumConstant) left).Child;
 146                                 if (right is EnumConstant)
 147                                         right = ((EnumConstant) right).Child;
 148
 149                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 150                                 return;
 151
 152                         } else {
 153                                 //
 154                                 // Force conversions to int32
 155                                 //
 156                                 if (!(left is IntConstant))
 157                                         left = left.ToInt (loc);
 158                                 if (!(right is IntConstant))
 159                                         right = right.ToInt (loc);
 160                         }
 161                         return;
 162                 }
 163
 164                 static void Error_CompileTimeOverflow (Location loc)
 165                 {
 166                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 167                 }
 168
 169                 /// <summary>
 170                 ///   Constant expression folder for binary operations.
 171                 ///
 172                 ///   Returns null if the expression can not be folded.
 173                 /// </summary>
 174                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 175                                                      Constant left, Constant right, Location loc)
 176                 {
 177                         if (left is NullCast)
 178                                 return BinaryFold (ec, oper, ((NullCast)left).child, right, loc);
 179
 180                         if (right is NullCast)
 181                                 return BinaryFold (ec, oper, left, ((NullCast)right).child, loc);
 182
 183                         Type lt = left.Type;
 184                         Type rt = right.Type;
 185                         Type result_type = null;
 186                         bool bool_res;
 187
 188                         //
 189                         // Enumerator folding
 190                         //
 191                         if (rt == lt && left is EnumConstant)
 192                                 result_type = lt;
 193
 194                         //
 195                         // During an enum evaluation, we need to unwrap enumerations
 196                         //
 197                         if (ec.InEnumContext){
 198                                 if (left is EnumConstant)
 199                                         left = ((EnumConstant) left).Child;
 200
 201                                 if (right is EnumConstant)
 202                                         right = ((EnumConstant) right).Child;
 203                         }
 204
 205                         Type wrap_as;
 206                         Constant result = null;
 207                         switch (oper){
 208                         case Binary.Operator.BitwiseOr:
 209                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 210                                 if (left == null || right == null)
 211                                         return null;
 212
 213                                 if (left is IntConstant){
 214                                         IntConstant v;
 215                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 216
 217                                         v = new IntConstant (res, left.Location);
 218                                         if (result_type == null)
 219                                                 return v;
 220                                         else
 221                                                 return new EnumConstant (v, result_type);
 222                                 } else if (left is UIntConstant){
 223                                         UIntConstant v;
 224                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 225
 226                                         v = new UIntConstant (res, left.Location);
 227                                         if (result_type == null)
 228                                                 return v;
 229                                         else
 230                                                 return new EnumConstant (v, result_type);
 231                                 } else if (left is LongConstant){
 232                                         LongConstant v;
 233                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 234
 235                                         v = new LongConstant (res, left.Location);
 236                                         if (result_type == null)
 237                                                 return v;
 238                                         else
 239                                                 return new EnumConstant (v, result_type);
 240                                 } else if (left is ULongConstant){
 241                                         ULongConstant v;
 242                                         ulong res = ((ULongConstant)left).Value |
 243                                                 ((ULongConstant)right).Value;
 244
 245                                         v = new ULongConstant (res, left.Location);
 246                                         if (result_type == null)
 247                                                 return v;
 248                                         else
 249                                                 return new EnumConstant (v, result_type);
 250                                 } else if (left is UShortConstant){
 251                                         UShortConstant v;
 252                                         ushort res = (ushort) (((UShortConstant)left).Value |
 253                                                                ((UShortConstant)right).Value);
 254
 255                                         v = new UShortConstant (res, left.Location);
 256                                         if (result_type == null)
 257                                                 return v;
 258                                         else
 259                                                 return new EnumConstant (v, result_type);
 260                                 } else if (left is ShortConstant){
 261                                         ShortConstant v;
 262                                         short res = (short) (((ShortConstant)left).Value |
 263                                                              ((ShortConstant)right).Value);
 264
 265                                         v = new ShortConstant (res, left.Location);
 266                                         if (result_type == null)
 267                                                 return v;
 268                                         else
 269                                                 return new EnumConstant (v, result_type);
 270                                 }
 271                                 break;
 272
 273                         case Binary.Operator.BitwiseAnd:
 274                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 275                                 if (left == null || right == null)
 276                                         return null;
 277
 278                                 if (left is IntConstant){
 279                                         IntConstant v;
 280                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 281
 282                                         v = new IntConstant (res, left.Location);
 283                                         if (result_type == null)
 284                                                 return v;
 285                                         else
 286                                                 return new EnumConstant (v, result_type);
 287                                 } else if (left is UIntConstant){
 288                                         UIntConstant v;
 289                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 290
 291                                         v = new UIntConstant (res, left.Location);
 292                                         if (result_type == null)
 293                                                 return v;
 294                                         else
 295                                                 return new EnumConstant (v, result_type);
 296                                 } else if (left is LongConstant){
 297                                         LongConstant v;
 298                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 299
 300                                         v = new LongConstant (res, left.Location);
 301                                         if (result_type == null)
 302                                                 return v;
 303                                         else
 304                                                 return new EnumConstant (v, result_type);
 305                                 } else if (left is ULongConstant){
 306                                         ULongConstant v;
 307                                         ulong res = ((ULongConstant)left).Value &
 308                                                 ((ULongConstant)right).Value;
 309
 310                                         v = new ULongConstant (res, left.Location);
 311                                         if (result_type == null)
 312                                                 return v;
 313                                         else
 314                                                 return new EnumConstant (v, result_type);
 315                                 } else if (left is UShortConstant){
 316                                         UShortConstant v;
 317                                         ushort res = (ushort) (((UShortConstant)left).Value &
 318                                                                ((UShortConstant)right).Value);
 319
 320                                         v = new UShortConstant (res, left.Location);
 321                                         if (result_type == null)
 322                                                 return v;
 323                                         else
 324                                                 return new EnumConstant (v, result_type);
 325                                 } else if (left is ShortConstant){
 326                                         ShortConstant v;
 327                                         short res = (short) (((ShortConstant)left).Value &
 328                                                              ((ShortConstant)right).Value);
 329
 330                                         v = new ShortConstant (res, left.Location);
 331                                         if (result_type == null)
 332                                                 return v;
 333                                         else
 334                                                 return new EnumConstant (v, result_type);
 335                                 }
 336                                 break;
 337
 338                         case Binary.Operator.ExclusiveOr:
 339                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 340                                 if (left == null || right == null)
 341                                         return null;
 342
 343                                 if (left is IntConstant){
 344                                         IntConstant v;
 345                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 346
 347                                         v = new IntConstant (res, left.Location);
 348                                         if (result_type == null)
 349                                                 return v;
 350                                         else
 351                                                 return new EnumConstant (v, result_type);
 352                                 } else if (left is UIntConstant){
 353                                         UIntConstant v;
 354                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 355
 356                                         v = new UIntConstant (res, left.Location);
 357                                         if (result_type == null)
 358                                                 return v;
 359                                         else
 360                                                 return new EnumConstant (v, result_type);
 361                                 } else if (left is LongConstant){
 362                                         LongConstant v;
 363                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 364
 365                                         v = new LongConstant (res, left.Location);
 366                                         if (result_type == null)
 367                                                 return v;
 368                                         else
 369                                                 return new EnumConstant (v, result_type);
 370                                 } else if (left is ULongConstant){
 371                                         ULongConstant v;
 372                                         ulong res = ((ULongConstant)left).Value ^
 373                                                 ((ULongConstant)right).Value;
 374
 375                                         v = new ULongConstant (res, left.Location);
 376                                         if (result_type == null)
 377                                                 return v;
 378                                         else
 379                                                 return new EnumConstant (v, result_type);
 380                                 } else if (left is UShortConstant){
 381                                         UShortConstant v;
 382                                         ushort res = (ushort) (((UShortConstant)left).Value ^
 383                                                                ((UShortConstant)right).Value);
 384
 385                                         v = new UShortConstant (res, left.Location);
 386                                         if (result_type == null)
 387                                                 return v;
 388                                         else
 389                                                 return new EnumConstant (v, result_type);
 390                                 } else if (left is ShortConstant){
 391                                         ShortConstant v;
 392                                         short res = (short)(((ShortConstant)left).Value ^
 393                                                             ((ShortConstant)right).Value);
 394
 395                                         v = new ShortConstant (res, left.Location);
 396                                         if (result_type == null)
 397                                                 return v;
 398                                         else
 399                                                 return new EnumConstant (v, result_type);
 400                                 }
 401                                 break;
 402
 403                         case Binary.Operator.Addition:
 404                                 bool left_is_string = left is StringConstant;
 405                                 bool right_is_string = right is StringConstant;
 406
 407                                 //
 408                                 // If both sides are strings, then concatenate, if
 409                                 // one is a string, and the other is not, then defer
 410                                 // to runtime concatenation
 411                                 //
 412                                 wrap_as = null;
 413                                 if (left_is_string || right_is_string){
 414                                         if (left_is_string && right_is_string)
 415                                                 return new StringConstant (
 416                                                         ((StringConstant) left).Value +
 417                                                         ((StringConstant) right).Value, left.Location);
 418
 419                                         return null;
 420                                 }
 421
 422                                 //
 423                                 // handle "E operator + (E x, U y)"
 424                                 // handle "E operator + (Y y, E x)"
 425                                 //
 426                                 // note that E operator + (E x, E y) is invalid
 427                                 //
 428                                 if (left is EnumConstant){
 429                                         if (right is EnumConstant){
 430                                                 return null;
 431                                         }
 432
 433                                         right = right.ToType (((EnumConstant) left).Child.Type, loc);
 434                                         if (right == null)
 435                                                 return null;
 436
 437                                         wrap_as = left.Type;
 438                                 } else if (right is EnumConstant){
 439                                         left = left.ToType (((EnumConstant) right).Child.Type, loc);
 440                                         if (left == null)
 441                                                 return null;
 442
 443                                         wrap_as = right.Type;
 444                                 }
 445
 446                                 result = null;
 447                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 448                                 if (left == null || right == null)
 449                                         return null;
 450
 451                                 try {
 452                                         if (left is DoubleConstant){
 453                                                 double res;
 454
 455                                                 if (ec.ConstantCheckState)
 456                                                         res = checked (((DoubleConstant) left).Value +
 457                                                                        ((DoubleConstant) right).Value);
 458                                                 else
 459                                                         res = unchecked (((DoubleConstant) left).Value +
 460                                                                          ((DoubleConstant) right).Value);
 461
 462                                                 result = new DoubleConstant (res, left.Location);
 463                                         } else if (left is FloatConstant){
 464                                                 float res;
 465
 466                                                 if (ec.ConstantCheckState)
 467                                                         res = checked (((FloatConstant) left).Value +
 468                                                                        ((FloatConstant) right).Value);
 469                                                 else
 470                                                         res = unchecked (((FloatConstant) left).Value +
 471                                                                          ((FloatConstant) right).Value);
 472
 473                                                 result = new FloatConstant (res, left.Location);
 474                                         } else if (left is ULongConstant){
 475                                                 ulong res;
 476
 477                                                 if (ec.ConstantCheckState)
 478                                                         res = checked (((ULongConstant) left).Value +
 479                                                                        ((ULongConstant) right).Value);
 480                                                 else
 481                                                         res = unchecked (((ULongConstant) left).Value +
 482                                                                          ((ULongConstant) right).Value);
 483
 484                                                 result = new ULongConstant (res, left.Location);
 485                                         } else if (left is LongConstant){
 486                                                 long res;
 487
 488                                                 if (ec.ConstantCheckState)
 489                                                         res = checked (((LongConstant) left).Value +
 490                                                                        ((LongConstant) right).Value);
 491                                                 else
 492                                                         res = unchecked (((LongConstant) left).Value +
 493                                                                          ((LongConstant) right).Value);
 494
 495                                                 result = new LongConstant (res, left.Location);
 496                                         } else if (left is UIntConstant){
 497                                                 uint res;
 498
 499                                                 if (ec.ConstantCheckState)
 500                                                         res = checked (((UIntConstant) left).Value +
 501                                                                        ((UIntConstant) right).Value);
 502                                                 else
 503                                                         res = unchecked (((UIntConstant) left).Value +
 504                                                                          ((UIntConstant) right).Value);
 505
 506                                                 result = new UIntConstant (res, left.Location);
 507                                         } else if (left is IntConstant){
 508                                                 int res;
 509
 510                                                 if (ec.ConstantCheckState)
 511                                                         res = checked (((IntConstant) left).Value +
 512                                                                        ((IntConstant) right).Value);
 513                                                 else
 514                                                         res = unchecked (((IntConstant) left).Value +
 515                                                                          ((IntConstant) right).Value);
 516
 517                                                 result = new IntConstant (res, left.Location);
 518                                         } else if (left is DecimalConstant) {
 519                                                 decimal res;
 520
 521                                                 if (ec.ConstantCheckState)
 522                                                         res = checked (((DecimalConstant) left).Value +
 523                                                                 ((DecimalConstant) right).Value);
 524                                                 else
 525                                                         res = unchecked (((DecimalConstant) left).Value +
 526                                                                 ((DecimalConstant) right).Value);
 527
 528                                                 result = new DecimalConstant (res, left.Location);
 529                                         } else {
 530                                                 throw new Exception ( "Unexepected addition input: " + left);
 531                                         }
 532                                 } catch (OverflowException){
 533                                         Error_CompileTimeOverflow (loc);
 534                                 }
 535
 536                                 if (wrap_as != null)
 537                                         return result.TryReduce (ec, wrap_as, loc);
 538                                 else
 539                                         return result;
 540
 541                         case Binary.Operator.Subtraction:
 542                                 //
 543                                 // handle "E operator - (E x, U y)"
 544                                 // handle "E operator - (Y y, E x)"
 545                                 // handle "U operator - (E x, E y)"
 546                                 //
 547                                 wrap_as = null;
 548                                 if (left is EnumConstant){
 549                                         if (right is EnumConstant){
 550                                                 if (left.Type != right.Type) {
 551                                                         Binary.Error_OperatorCannotBeApplied (loc, "-", left.Type, right.Type);
 552                                                         return null;
 553                                                 }
 554
 555                                                 wrap_as = TypeManager.EnumToUnderlying (left.Type);
 556                                                 right = ((EnumConstant) right).Child.ToType (wrap_as, loc);
 557                                                 if (right == null)
 558                                                         return null;
 559
 560                                                 left = ((EnumConstant) left).Child.ToType (wrap_as, loc);
 561                                                 if (left == null)
 562                                                         return null;
 563                                         }
 564                                         else {
 565                                                 right = right.ToType (((EnumConstant) left).Child.Type, loc);
 566                                                 if (right == null)
 567                                                         return null;
 568
 569                                                 wrap_as = left.Type;
 570                                         }
 571                                 } else if (right is EnumConstant){
 572                                         left = left.ToType (((EnumConstant) right).Child.Type, loc);
 573                                         if (left == null)
 574                                                 return null;
 575
 576                                         wrap_as = right.Type;
 577                                 }
 578
 579                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 580                                 if (left == null || right == null)
 581                                         return null;
 582
 583                                 try {
 584                                         if (left is DoubleConstant){
 585                                                 double res;
 586
 587                                                 if (ec.ConstantCheckState)
 588                                                         res = checked (((DoubleConstant) left).Value -
 589                                                                        ((DoubleConstant) right).Value);
 590                                                 else
 591                                                         res = unchecked (((DoubleConstant) left).Value -
 592                                                                          ((DoubleConstant) right).Value);
 593
 594                                                 result = new DoubleConstant (res, left.Location);
 595                                         } else if (left is FloatConstant){
 596                                                 float res;
 597
 598                                                 if (ec.ConstantCheckState)
 599                                                         res = checked (((FloatConstant) left).Value -
 600                                                                        ((FloatConstant) right).Value);
 601                                                 else
 602                                                         res = unchecked (((FloatConstant) left).Value -
 603                                                                          ((FloatConstant) right).Value);
 604
 605                                                 result = new FloatConstant (res, left.Location);
 606                                         } else if (left is ULongConstant){
 607                                                 ulong res;
 608
 609                                                 if (ec.ConstantCheckState)
 610                                                         res = checked (((ULongConstant) left).Value -
 611                                                                        ((ULongConstant) right).Value);
 612                                                 else
 613                                                         res = unchecked (((ULongConstant) left).Value -
 614                                                                          ((ULongConstant) right).Value);
 615
 616                                                 result = new ULongConstant (res, left.Location);
 617                                         } else if (left is LongConstant){
 618                                                 long res;
 619
 620                                                 if (ec.ConstantCheckState)
 621                                                         res = checked (((LongConstant) left).Value -
 622                                                                        ((LongConstant) right).Value);
 623                                                 else
 624                                                         res = unchecked (((LongConstant) left).Value -
 625                                                                          ((LongConstant) right).Value);
 626
 627                                                 result = new LongConstant (res, left.Location);
 628                                         } else if (left is UIntConstant){
 629                                                 uint res;
 630
 631                                                 if (ec.ConstantCheckState)
 632                                                         res = checked (((UIntConstant) left).Value -
 633                                                                        ((UIntConstant) right).Value);
 634                                                 else
 635                                                         res = unchecked (((UIntConstant) left).Value -
 636                                                                          ((UIntConstant) right).Value);
 637
 638                                                 result = new UIntConstant (res, left.Location);
 639                                         } else if (left is IntConstant){
 640                                                 int res;
 641
 642                                                 if (ec.ConstantCheckState)
 643                                                         res = checked (((IntConstant) left).Value -
 644                                                                        ((IntConstant) right).Value);
 645                                                 else
 646                                                         res = unchecked (((IntConstant) left).Value -
 647                                                                          ((IntConstant) right).Value);
 648
 649                                                 result = new IntConstant (res, left.Location);
 650                                         } else if (left is DecimalConstant) {
 651                                                 decimal res;
 652
 653                                                 if (ec.ConstantCheckState)
 654                                                         res = checked (((DecimalConstant) left).Value -
 655                                                                 ((DecimalConstant) right).Value);
 656                                                 else
 657                                                         res = unchecked (((DecimalConstant) left).Value -
 658                                                                 ((DecimalConstant) right).Value);
 659
 660                                                 return new DecimalConstant (res, left.Location);
 661                                         } else {
 662                                                 throw new Exception ( "Unexepected subtraction input: " + left);
 663                                         }
 664                                 } catch (OverflowException){
 665                                         Error_CompileTimeOverflow (loc);
 666                                 }
 667
 668                                 if (wrap_as != null)
 669                                         return result.TryReduce (ec, wrap_as, loc);
 670
 671                                 return result;
 672
 673                         case Binary.Operator.Multiply:
 674                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 675                                 if (left == null || right == null)
 676                                         return null;
 677
 678                                 try {
 679                                         if (left is DoubleConstant){
 680                                                 double res;
 681
 682                                                 if (ec.ConstantCheckState)
 683                                                         res = checked (((DoubleConstant) left).Value *
 684                                                                 ((DoubleConstant) right).Value);
 685                                                 else
 686                                                         res = unchecked (((DoubleConstant) left).Value *
 687                                                                 ((DoubleConstant) right).Value);
 688
 689                                                 return new DoubleConstant (res, left.Location);
 690                                         } else if (left is FloatConstant){
 691                                                 float res;
 692
 693                                                 if (ec.ConstantCheckState)
 694                                                         res = checked (((FloatConstant) left).Value *
 695                                                                 ((FloatConstant) right).Value);
 696                                                 else
 697                                                         res = unchecked (((FloatConstant) left).Value *
 698                                                                 ((FloatConstant) right).Value);
 699
 700                                                 return new FloatConstant (res, left.Location);
 701                                         } else if (left is ULongConstant){
 702                                                 ulong res;
 703
 704                                                 if (ec.ConstantCheckState)
 705                                                         res = checked (((ULongConstant) left).Value *
 706                                                                 ((ULongConstant) right).Value);
 707                                                 else
 708                                                         res = unchecked (((ULongConstant) left).Value *
 709                                                                 ((ULongConstant) right).Value);
 710
 711                                                 return new ULongConstant (res, left.Location);
 712                                         } else if (left is LongConstant){
 713                                                 long res;
 714
 715                                                 if (ec.ConstantCheckState)
 716                                                         res = checked (((LongConstant) left).Value *
 717                                                                 ((LongConstant) right).Value);
 718                                                 else
 719                                                         res = unchecked (((LongConstant) left).Value *
 720                                                                 ((LongConstant) right).Value);
 721
 722                                                 return new LongConstant (res, left.Location);
 723                                         } else if (left is UIntConstant){
 724                                                 uint res;
 725
 726                                                 if (ec.ConstantCheckState)
 727                                                         res = checked (((UIntConstant) left).Value *
 728                                                                 ((UIntConstant) right).Value);
 729                                                 else
 730                                                         res = unchecked (((UIntConstant) left).Value *
 731                                                                 ((UIntConstant) right).Value);
 732
 733                                                 return new UIntConstant (res, left.Location);
 734                                         } else if (left is IntConstant){
 735                                                 int res;
 736
 737                                                 if (ec.ConstantCheckState)
 738                                                         res = checked (((IntConstant) left).Value *
 739                                                                 ((IntConstant) right).Value);
 740                                                 else
 741                                                         res = unchecked (((IntConstant) left).Value *
 742                                                                 ((IntConstant) right).Value);
 743
 744                                                 return new IntConstant (res, left.Location);
 745                                         } else if (left is DecimalConstant) {
 746                                                 decimal res;
 747
 748                                                 if (ec.ConstantCheckState)
 749                                                         res = checked (((DecimalConstant) left).Value *
 750                                                                 ((DecimalConstant) right).Value);
 751                                                 else
 752                                                         res = unchecked (((DecimalConstant) left).Value *
 753                                                                 ((DecimalConstant) right).Value);
 754
 755                                                 return new DecimalConstant (res, left.Location);
 756                                         } else {
 757                                                 throw new Exception ( "Unexepected multiply input: " + left);
 758                                         }
 759                                 } catch (OverflowException){
 760                                         Error_CompileTimeOverflow (loc);
 761                                 }
 762                                 break;
 763
 764                         case Binary.Operator.Division:
 765                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 766                                 if (left == null || right == null)
 767                                         return null;
 768
 769                                 try {
 770                                         if (left is DoubleConstant){
 771                                                 double res;
 772
 773                                                 if (ec.ConstantCheckState)
 774                                                         res = checked (((DoubleConstant) left).Value /
 775                                                                 ((DoubleConstant) right).Value);
 776                                                 else
 777                                                         res = unchecked (((DoubleConstant) left).Value /
 778                                                                 ((DoubleConstant) right).Value);
 779
 780                                                 return new DoubleConstant (res, left.Location);
 781                                         } else if (left is FloatConstant){
 782                                                 float res;
 783
 784                                                 if (ec.ConstantCheckState)
 785                                                         res = checked (((FloatConstant) left).Value /
 786                                                                 ((FloatConstant) right).Value);
 787                                                 else
 788                                                         res = unchecked (((FloatConstant) left).Value /
 789                                                                 ((FloatConstant) right).Value);
 790
 791                                                 return new FloatConstant (res, left.Location);
 792                                         } else if (left is ULongConstant){
 793                                                 ulong res;
 794
 795                                                 if (ec.ConstantCheckState)
 796                                                         res = checked (((ULongConstant) left).Value /
 797                                                                 ((ULongConstant) right).Value);
 798                                                 else
 799                                                         res = unchecked (((ULongConstant) left).Value /
 800                                                                 ((ULongConstant) right).Value);
 801
 802                                                 return new ULongConstant (res, left.Location);
 803                                         } else if (left is LongConstant){
 804                                                 long res;
 805
 806                                                 if (ec.ConstantCheckState)
 807                                                         res = checked (((LongConstant) left).Value /
 808                                                                 ((LongConstant) right).Value);
 809                                                 else
 810                                                         res = unchecked (((LongConstant) left).Value /
 811                                                                 ((LongConstant) right).Value);
 812
 813                                                 return new LongConstant (res, left.Location);
 814                                         } else if (left is UIntConstant){
 815                                                 uint res;
 816
 817                                                 if (ec.ConstantCheckState)
 818                                                         res = checked (((UIntConstant) left).Value /
 819                                                                 ((UIntConstant) right).Value);
 820                                                 else
 821                                                         res = unchecked (((UIntConstant) left).Value /
 822                                                                 ((UIntConstant) right).Value);
 823
 824                                                 return new UIntConstant (res, left.Location);
 825                                         } else if (left is IntConstant){
 826                                                 int res;
 827
 828                                                 if (ec.ConstantCheckState)
 829                                                         res = checked (((IntConstant) left).Value /
 830                                                                 ((IntConstant) right).Value);
 831                                                 else
 832                                                         res = unchecked (((IntConstant) left).Value /
 833                                                                 ((IntConstant) right).Value);
 834
 835                                                 return new IntConstant (res, left.Location);
 836                                         } else if (left is DecimalConstant) {
 837                                                 decimal res;
 838
 839                                                 if (ec.ConstantCheckState)
 840                                                         res = checked (((DecimalConstant) left).Value /
 841                                                                 ((DecimalConstant) right).Value);
 842                                                 else
 843                                                         res = unchecked (((DecimalConstant) left).Value /
 844                                                                 ((DecimalConstant) right).Value);
 845
 846                                                 return new DecimalConstant (res, left.Location);
 847                                         } else {
 848                                                 throw new Exception ( "Unexepected division input: " + left);
 849                                         }
 850                                 } catch (OverflowException){
 851                                         Error_CompileTimeOverflow (loc);
 852
 853                                 } catch (DivideByZeroException) {
 854                                         Report.Error (020, loc, "Division by constant zero");
 855                                 }
 856
 857                                 break;
 858
 859                         case Binary.Operator.Modulus:
 860                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 861                                 if (left == null || right == null)
 862                                         return null;
 863
 864                                 try {
 865                                         if (left is DoubleConstant){
 866                                                 double res;
 867
 868                                                 if (ec.ConstantCheckState)
 869                                                         res = checked (((DoubleConstant) left).Value %
 870                                                                        ((DoubleConstant) right).Value);
 871                                                 else
 872                                                         res = unchecked (((DoubleConstant) left).Value %
 873                                                                          ((DoubleConstant) right).Value);
 874
 875                                                 return new DoubleConstant (res, left.Location);
 876                                         } else if (left is FloatConstant){
 877                                                 float res;
 878
 879                                                 if (ec.ConstantCheckState)
 880                                                         res = checked (((FloatConstant) left).Value %
 881                                                                        ((FloatConstant) right).Value);
 882                                                 else
 883                                                         res = unchecked (((FloatConstant) left).Value %
 884                                                                          ((FloatConstant) right).Value);
 885
 886                                                 return new FloatConstant (res, left.Location);
 887                                         } else if (left is ULongConstant){
 888                                                 ulong res;
 889
 890                                                 if (ec.ConstantCheckState)
 891                                                         res = checked (((ULongConstant) left).Value %
 892                                                                        ((ULongConstant) right).Value);
 893                                                 else
 894                                                         res = unchecked (((ULongConstant) left).Value %
 895                                                                          ((ULongConstant) right).Value);
 896
 897                                                 return new ULongConstant (res, left.Location);
 898                                         } else if (left is LongConstant){
 899                                                 long res;
 900
 901                                                 if (ec.ConstantCheckState)
 902                                                         res = checked (((LongConstant) left).Value %
 903                                                                        ((LongConstant) right).Value);
 904                                                 else
 905                                                         res = unchecked (((LongConstant) left).Value %
 906                                                                          ((LongConstant) right).Value);
 907
 908                                                 return new LongConstant (res, left.Location);
 909                                         } else if (left is UIntConstant){
 910                                                 uint res;
 911
 912                                                 if (ec.ConstantCheckState)
 913                                                         res = checked (((UIntConstant) left).Value %
 914                                                                        ((UIntConstant) right).Value);
 915                                                 else
 916                                                         res = unchecked (((UIntConstant) left).Value %
 917                                                                          ((UIntConstant) right).Value);
 918
 919                                                 return new UIntConstant (res, left.Location);
 920                                         } else if (left is IntConstant){
 921                                                 int res;
 922
 923                                                 if (ec.ConstantCheckState)
 924                                                         res = checked (((IntConstant) left).Value %
 925                                                                        ((IntConstant) right).Value);
 926                                                 else
 927                                                         res = unchecked (((IntConstant) left).Value %
 928                                                                          ((IntConstant) right).Value);
 929
 930                                                 return new IntConstant (res, left.Location);
 931                                         } else {
 932                                                 throw new Exception ( "Unexepected modulus input: " + left);
 933                                         }
 934                                 } catch (DivideByZeroException){
 935                                         Report.Error (020, loc, "Division by constant zero");
 936                                 } catch (OverflowException){
 937                                         Error_CompileTimeOverflow (loc);
 938                                 }
 939                                 break;
 940
 941                                 //
 942                                 // There is no overflow checking on left shift
 943                                 //
 944                         case Binary.Operator.LeftShift:
 945                                 IntConstant ic = right.ToInt (loc);
 946                                 if (ic == null){
 947                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 948                                         return null;
 949                                 }
 950                                 int lshift_val = ic.Value;
 951
 952                                 IntConstant lic;
 953                                 if ((lic = left.ConvertToInt ()) != null)
 954                                         return new IntConstant (lic.Value << lshift_val, left.Location);
 955
 956                                 UIntConstant luic;
 957                                 if ((luic = left.ConvertToUInt ()) != null)
 958                                         return new UIntConstant (luic.Value << lshift_val, left.Location);
 959
 960                                 LongConstant llc;
 961                                 if ((llc = left.ConvertToLong ()) != null)
 962                                         return new LongConstant (llc.Value << lshift_val, left.Location);
 963
 964                                 ULongConstant lulc;
 965                                 if ((lulc = left.ConvertToULong ()) != null)
 966                                         return new ULongConstant (lulc.Value << lshift_val, left.Location);
 967
 968                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 969                                 break;
 970
 971                                 //
 972                                 // There is no overflow checking on right shift
 973                                 //
 974                         case Binary.Operator.RightShift:
 975                                 IntConstant sic = right.ToInt (loc);
 976                                 if (sic == null){
 977                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 978                                         return null;
 979                                 }
 980                                 int rshift_val = sic.Value;
 981
 982                                 IntConstant ric;
 983                                 if ((ric = left.ConvertToInt ()) != null)
 984                                         return new IntConstant (ric.Value >> rshift_val, left.Location);
 985
 986                                 UIntConstant ruic;
 987                                 if ((ruic = left.ConvertToUInt ()) != null)
 988                                         return new UIntConstant (ruic.Value >> rshift_val, left.Location);
 989
 990                                 LongConstant rlc;
 991                                 if ((rlc = left.ConvertToLong ()) != null)
 992                                         return new LongConstant (rlc.Value >> rshift_val, left.Location);
 993
 994                                 ULongConstant rulc;
 995                                 if ((rulc = left.ConvertToULong ()) != null)
 996                                         return new ULongConstant (rulc.Value >> rshift_val, left.Location);
 997
 998                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 999                                 break;
1000
1001                         case Binary.Operator.LogicalAnd:
1002                                 if (left is BoolConstant && right is BoolConstant){
1003                                         return new BoolConstant (
1004                                                 ((BoolConstant) left).Value &&
1005                                                 ((BoolConstant) right).Value, left.Location);
1006                                 }
1007                                 break;
1008
1009                         case Binary.Operator.LogicalOr:
1010                                 if (left is BoolConstant && right is BoolConstant){
1011                                         return new BoolConstant (
1012                                                 ((BoolConstant) left).Value ||
1013                                                 ((BoolConstant) right).Value, left.Location);
1014                                 }
1015                                 break;
1016
1017                         case Binary.Operator.Equality:
1018                                 if (left is BoolConstant && right is BoolConstant){
1019                                         return new BoolConstant (
1020                                                 ((BoolConstant) left).Value ==
1021                                                 ((BoolConstant) right).Value, left.Location);
1022
1023                                 }
1024                                 if (left is NullLiteral){
1025                                         if (right is NullLiteral)
1026                                                 return new BoolConstant (true, left.Location);
1027                                         else if (right is StringConstant)
1028                                                 return new BoolConstant (
1029                                                         ((StringConstant) right).Value == null, left.Location);
1030                                 } else if (right is NullLiteral){
1031                                         if (left is NullLiteral)
1032                                                 return new BoolConstant (true, left.Location);
1033                                         else if (left is StringConstant)
1034                                                 return new BoolConstant (
1035                                                         ((StringConstant) left).Value == null, left.Location);
1036                                 }
1037                                 if (left is StringConstant && right is StringConstant){
1038                                         return new BoolConstant (
1039                                                 ((StringConstant) left).Value ==
1040                                                 ((StringConstant) right).Value, left.Location);
1041
1042                                 }
1043
1044                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1045                                 if (left == null || right == null)
1046                                         return null;
1047
1048                                 bool_res = false;
1049                                 if (left is DoubleConstant)
1050                                         bool_res = ((DoubleConstant) left).Value ==
1051                                                 ((DoubleConstant) right).Value;
1052                                 else if (left is FloatConstant)
1053                                         bool_res = ((FloatConstant) left).Value ==
1054                                                 ((FloatConstant) right).Value;
1055                                 else if (left is ULongConstant)
1056                                         bool_res = ((ULongConstant) left).Value ==
1057                                                 ((ULongConstant) right).Value;
1058                                 else if (left is LongConstant)
1059                                         bool_res = ((LongConstant) left).Value ==
1060                                                 ((LongConstant) right).Value;
1061                                 else if (left is UIntConstant)
1062                                         bool_res = ((UIntConstant) left).Value ==
1063                                                 ((UIntConstant) right).Value;
1064                                 else if (left is IntConstant)
1065                                         bool_res = ((IntConstant) left).Value ==
1066                                                 ((IntConstant) right).Value;
1067                                 else
1068                                         return null;
1069
1070                                 return new BoolConstant (bool_res, left.Location);
1071
1072                         case Binary.Operator.Inequality:
1073                                 if (left is BoolConstant && right is BoolConstant){
1074                                         return new BoolConstant (
1075                                                 ((BoolConstant) left).Value !=
1076                                                 ((BoolConstant) right).Value, left.Location);
1077                                 }
1078                                 if (left is NullLiteral){
1079                                         if (right is NullLiteral)
1080                                                 return new BoolConstant (false, left.Location);
1081                                         else if (right is StringConstant)
1082                                                 return new BoolConstant (
1083                                                         ((StringConstant) right).Value != null, left.Location);
1084                                 } else if (right is NullLiteral){
1085                                         if (left is NullLiteral)
1086                                                 return new BoolConstant (false, left.Location);
1087                                         else if (left is StringConstant)
1088                                                 return new BoolConstant (
1089                                                         ((StringConstant) left).Value != null, left.Location);
1090                                 }
1091                                 if (left is StringConstant && right is StringConstant){
1092                                         return new BoolConstant (
1093                                                 ((StringConstant) left).Value !=
1094                                                 ((StringConstant) right).Value, left.Location);
1095
1096                                 }
1097                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1098                                 if (left == null || right == null)
1099                                         return null;
1100
1101                                 bool_res = false;
1102                                 if (left is DoubleConstant)
1103                                         bool_res = ((DoubleConstant) left).Value !=
1104                                                 ((DoubleConstant) right).Value;
1105                                 else if (left is FloatConstant)
1106                                         bool_res = ((FloatConstant) left).Value !=
1107                                                 ((FloatConstant) right).Value;
1108                                 else if (left is ULongConstant)
1109                                         bool_res = ((ULongConstant) left).Value !=
1110                                                 ((ULongConstant) right).Value;
1111                                 else if (left is LongConstant)
1112                                         bool_res = ((LongConstant) left).Value !=
1113                                                 ((LongConstant) right).Value;
1114                                 else if (left is UIntConstant)
1115                                         bool_res = ((UIntConstant) left).Value !=
1116                                                 ((UIntConstant) right).Value;
1117                                 else if (left is IntConstant)
1118                                         bool_res = ((IntConstant) left).Value !=
1119                                                 ((IntConstant) right).Value;
1120                                 else
1121                                         return null;
1122
1123                                 return new BoolConstant (bool_res, left.Location);
1124
1125                         case Binary.Operator.LessThan:
1126                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1127                                 if (left == null || right == null)
1128                                         return null;
1129
1130                                 bool_res = false;
1131                                 if (left is DoubleConstant)
1132                                         bool_res = ((DoubleConstant) left).Value <
1133                                                 ((DoubleConstant) right).Value;
1134                                 else if (left is FloatConstant)
1135                                         bool_res = ((FloatConstant) left).Value <
1136                                                 ((FloatConstant) right).Value;
1137                                 else if (left is ULongConstant)
1138                                         bool_res = ((ULongConstant) left).Value <
1139                                                 ((ULongConstant) right).Value;
1140                                 else if (left is LongConstant)
1141                                         bool_res = ((LongConstant) left).Value <
1142                                                 ((LongConstant) right).Value;
1143                                 else if (left is UIntConstant)
1144                                         bool_res = ((UIntConstant) left).Value <
1145                                                 ((UIntConstant) right).Value;
1146                                 else if (left is IntConstant)
1147                                         bool_res = ((IntConstant) left).Value <
1148                                                 ((IntConstant) right).Value;
1149                                 else
1150                                         return null;
1151
1152                                 return new BoolConstant (bool_res, left.Location);
1153
1154                         case Binary.Operator.GreaterThan:
1155                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1156                                 if (left == null || right == null)
1157                                         return null;
1158
1159                                 bool_res = false;
1160                                 if (left is DoubleConstant)
1161                                         bool_res = ((DoubleConstant) left).Value >
1162                                                 ((DoubleConstant) right).Value;
1163                                 else if (left is FloatConstant)
1164                                         bool_res = ((FloatConstant) left).Value >
1165                                                 ((FloatConstant) right).Value;
1166                                 else if (left is ULongConstant)
1167                                         bool_res = ((ULongConstant) left).Value >
1168                                                 ((ULongConstant) right).Value;
1169                                 else if (left is LongConstant)
1170                                         bool_res = ((LongConstant) left).Value >
1171                                                 ((LongConstant) right).Value;
1172                                 else if (left is UIntConstant)
1173                                         bool_res = ((UIntConstant) left).Value >
1174                                                 ((UIntConstant) right).Value;
1175                                 else if (left is IntConstant)
1176                                         bool_res = ((IntConstant) left).Value >
1177                                                 ((IntConstant) right).Value;
1178                                 else
1179                                         return null;
1180
1181                                 return new BoolConstant (bool_res, left.Location);
1182
1183                         case Binary.Operator.GreaterThanOrEqual:
1184                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1185                                 if (left == null || right == null)
1186                                         return null;
1187
1188                                 bool_res = false;
1189                                 if (left is DoubleConstant)
1190                                         bool_res = ((DoubleConstant) left).Value >=
1191                                                 ((DoubleConstant) right).Value;
1192                                 else if (left is FloatConstant)
1193                                         bool_res = ((FloatConstant) left).Value >=
1194                                                 ((FloatConstant) right).Value;
1195                                 else if (left is ULongConstant)
1196                                         bool_res = ((ULongConstant) left).Value >=
1197                                                 ((ULongConstant) right).Value;
1198                                 else if (left is LongConstant)
1199                                         bool_res = ((LongConstant) left).Value >=
1200                                                 ((LongConstant) right).Value;
1201                                 else if (left is UIntConstant)
1202                                         bool_res = ((UIntConstant) left).Value >=
1203                                                 ((UIntConstant) right).Value;
1204                                 else if (left is IntConstant)
1205                                         bool_res = ((IntConstant) left).Value >=
1206                                                 ((IntConstant) right).Value;
1207                                 else
1208                                         return null;
1209
1210                                 return new BoolConstant (bool_res, left.Location);
1211
1212                         case Binary.Operator.LessThanOrEqual:
1213                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1214                                 if (left == null || right == null)
1215                                         return null;
1216
1217                                 bool_res = false;
1218                                 if (left is DoubleConstant)
1219                                         bool_res = ((DoubleConstant) left).Value <=
1220                                                 ((DoubleConstant) right).Value;
1221                                 else if (left is FloatConstant)
1222                                         bool_res = ((FloatConstant) left).Value <=
1223                                                 ((FloatConstant) right).Value;
1224                                 else if (left is ULongConstant)
1225                                         bool_res = ((ULongConstant) left).Value <=
1226                                                 ((ULongConstant) right).Value;
1227                                 else if (left is LongConstant)
1228                                         bool_res = ((LongConstant) left).Value <=
1229                                                 ((LongConstant) right).Value;
1230                                 else if (left is UIntConstant)
1231                                         bool_res = ((UIntConstant) left).Value <=
1232                                                 ((UIntConstant) right).Value;
1233                                 else if (left is IntConstant)
1234                                         bool_res = ((IntConstant) left).Value <=
1235                                                 ((IntConstant) right).Value;
1236                                 else
1237                                         return null;
1238
1239                                 return new BoolConstant (bool_res, left.Location);
1240                         }
1241
1242                         return null;
1243                 }
1244         }
1245 }