mcs/mcs/cfold.cs

   1 //
   2 // cfold.cs: Constant Folding
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2002 Ximian, Inc.
   8 //
   9
  10 using System;
  11
  12 namespace Mono.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                 //
  30                 static void DoConstantNumericPromotions (Binary.Operator oper,
  31                                                          ref Constant left, ref Constant right,
  32                                                          Location loc)
  33                 {
  34                         if (left is DoubleConstant || right is DoubleConstant){
  35                                 //
  36                                 // If either side is a double, convert the other to a double
  37                                 //
  38                                 if (!(left is DoubleConstant))
  39                                         left = left.ToDouble (loc);
  40
  41                                 if (!(right is DoubleConstant))
  42                                         right = right.ToDouble (loc);
  43                                 return;
  44                         } else if (left is FloatConstant || right is FloatConstant) {
  45                                 //
  46                                 // If either side is a float, convert the other to a float
  47                                 //
  48                                 if (!(left is FloatConstant))
  49                                         left = left.ToFloat (loc);
  50
  51                                 if (!(right is FloatConstant))
  52                                         right = right.ToFloat (loc);
  53                                 return;
  54                         } else if (left is ULongConstant || right is ULongConstant){
  55                                 //
  56                                 // If either operand is of type ulong, the other operand is
  57                                 // converted to type ulong.  or an error ocurrs if the other
  58                                 // operand is of type sbyte, short, int or long
  59                                 //
  60                                 Constant match, other;
  61
  62                                 if (left is ULongConstant){
  63                                         other = right;
  64                                         match = left;
  65                                         if (!(right is ULongConstant))
  66                                                 right = right.ToULong (loc);
  67                                 } else {
  68                                         other = left;
  69                                         match = right;
  70                                         left = left.ToULong (loc);
  71                                 }
  72
  73                                 if (other is SByteConstant || other is ShortConstant ||
  74                                     other is IntConstant || other is LongConstant){
  75                                         Binary.Error_OperatorAmbiguous
  76                                                 (loc, oper, other.Type, match.Type);
  77                                         left = null;
  78                                         right = null;
  79                                 }
  80                                 return;
  81                         } else if (left is LongConstant || right is LongConstant){
  82                                 //
  83                                 // If either operand is of type long, the other operand is converted
  84                                 // to type long.
  85                                 //
  86                                 if (!(left is LongConstant))
  87                                         left = left.ToLong (loc);
  88                                 else if (!(right is LongConstant))
  89                                         right = right.ToLong (loc);
  90                                 return;
  91                         } else if (left is UIntConstant || right is UIntConstant){
  92                                 //
  93                                 // If either operand is of type uint, and the other
  94                                 // operand is of type sbyte, short or int, othe operands are
  95                                 // converted to type long.
  96                                 //
  97                                 if (!(left is UIntConstant))
  98                                         left = left.ToUInt (loc);
  99                                 else if (!(right is UIntConstant))
 100                                         right = right.ToUInt (loc);
 101                                 return;
 102                         } else {
 103                                 //
 104                                 // Force conversions to int32
 105                                 //
 106                                 if (!(left is IntConstant))
 107                                         left = left.ToInt (loc);
 108                                 if (!(right is IntConstant))
 109                                         right = right.ToInt (loc);
 110                         }
 111                         return;
 112                 }
 113
 114                 static void Error_CompileTimeOverflow (Location loc)
 115                 {
 116                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 117                 }
 118
 119                 /// <summary>
 120                 ///   Constant expression folder for binary operations.
 121                 ///
 122                 ///   Returns null if the expression can not be folded.
 123                 /// </summary>
 124                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 125                                                      Constant left, Constant right, Location loc)
 126                 {
 127                         Type lt = left.Type;
 128                         Type rt = right.Type;
 129                         Type result_type = null;
 130                         bool bool_res;
 131
 132                         //
 133                         // Enumerator folding
 134                         //
 135                         if (rt == lt && left is EnumConstant)
 136                                 result_type = lt;
 137
 138                         switch (oper){
 139                         case Binary.Operator.BitwiseOr:
 140                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 141                                 if (left == null || right == null)
 142                                         return null;
 143
 144                                 if (left is IntConstant){
 145                                         IntConstant v;
 146                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 147
 148                                         v = new IntConstant (res);
 149                                         if (result_type == null)
 150                                                 return v;
 151                                         else
 152                                                 return new EnumConstant (v, result_type);
 153                                 } else if (left is UIntConstant){
 154                                         UIntConstant v;
 155                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 156
 157                                         v = new UIntConstant (res);
 158                                         if (result_type == null)
 159                                                 return v;
 160                                         else
 161                                                 return new EnumConstant (v, result_type);
 162                                 } else if (left is LongConstant){
 163                                         LongConstant v;
 164                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 165
 166                                         v = new LongConstant (res);
 167                                         if (result_type == null)
 168                                                 return v;
 169                                         else
 170                                                 return new EnumConstant (v, result_type);
 171                                 } else if (left is ULongConstant){
 172                                         ULongConstant v;
 173                                         ulong res = ((ULongConstant)left).Value |
 174                                                 ((ULongConstant)right).Value;
 175
 176                                         v = new ULongConstant (res);
 177                                         if (result_type == null)
 178                                                 return v;
 179                                         else
 180                                                 return new EnumConstant (v, result_type);
 181                                 }
 182                                 break;
 183
 184                         case Binary.Operator.BitwiseAnd:
 185                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 186                                 if (left == null || right == null)
 187                                         return null;
 188
 189                                 if (left is IntConstant){
 190                                         IntConstant v;
 191                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 192
 193                                         v = new IntConstant (res);
 194                                         if (result_type == null)
 195                                                 return v;
 196                                         else
 197                                                 return new EnumConstant (v, result_type);
 198                                 } else if (left is UIntConstant){
 199                                         UIntConstant v;
 200                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 201
 202                                         v = new UIntConstant (res);
 203                                         if (result_type == null)
 204                                                 return v;
 205                                         else
 206                                                 return new EnumConstant (v, result_type);
 207                                 } else if (left is LongConstant){
 208                                         LongConstant v;
 209                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 210
 211                                         v = new LongConstant (res);
 212                                         if (result_type == null)
 213                                                 return v;
 214                                         else
 215                                                 return new EnumConstant (v, result_type);
 216                                 } else if (left is ULongConstant){
 217                                         ULongConstant v;
 218                                         ulong res = ((ULongConstant)left).Value &
 219                                                 ((ULongConstant)right).Value;
 220
 221                                         v = new ULongConstant (res);
 222                                         if (result_type == null)
 223                                                 return v;
 224                                         else
 225                                                 return new EnumConstant (v, result_type);
 226                                 }
 227                                 break;
 228
 229                         case Binary.Operator.ExclusiveOr:
 230                                 DoConstantNumericPromotions (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                                 }
 272                                 break;
 273
 274                         case Binary.Operator.Addition:
 275                                 bool left_is_string = left is StringConstant;
 276                                 bool right_is_string = right is StringConstant;
 277
 278                                 //
 279                                 // If both sides are strings, then concatenate, if
 280                                 // one is a string, and the other is not, then defer
 281                                 // to runtime concatenation
 282                                 //
 283                                 if (left_is_string || right_is_string){
 284                                         if (left_is_string && right_is_string)
 285                                                 return new StringConstant (
 286                                                         ((StringConstant) left).Value +
 287                                                         ((StringConstant) right).Value);
 288
 289                                         return null;
 290                                 }
 291
 292                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 293                                 if (left == null || right == null)
 294                                         return null;
 295
 296                                 try {
 297                                         if (left is DoubleConstant){
 298                                                 double res;
 299
 300                                                 if (ec.ConstantCheckState)
 301                                                         res = checked (((DoubleConstant) left).Value +
 302                                                                        ((DoubleConstant) right).Value);
 303                                                 else
 304                                                         res = unchecked (((DoubleConstant) left).Value +
 305                                                                          ((DoubleConstant) right).Value);
 306
 307                                                 return new DoubleConstant (res);
 308                                         } else if (left is FloatConstant){
 309                                                 float res;
 310
 311                                                 if (ec.ConstantCheckState)
 312                                                         res = checked (((FloatConstant) left).Value +
 313                                                                        ((FloatConstant) right).Value);
 314                                                 else
 315                                                         res = unchecked (((FloatConstant) left).Value +
 316                                                                          ((FloatConstant) right).Value);
 317
 318                                                 return new FloatConstant (res);
 319                                         } else if (left is ULongConstant){
 320                                                 ulong res;
 321
 322                                                 if (ec.ConstantCheckState)
 323                                                         res = checked (((ULongConstant) left).Value +
 324                                                                        ((ULongConstant) right).Value);
 325                                                 else
 326                                                         res = unchecked (((ULongConstant) left).Value +
 327                                                                          ((ULongConstant) right).Value);
 328
 329                                                 return new ULongConstant (res);
 330                                         } else if (left is LongConstant){
 331                                                 long res;
 332
 333                                                 if (ec.ConstantCheckState)
 334                                                         res = checked (((LongConstant) left).Value +
 335                                                                        ((LongConstant) right).Value);
 336                                                 else
 337                                                         res = unchecked (((LongConstant) left).Value +
 338                                                                          ((LongConstant) right).Value);
 339
 340                                                 return new LongConstant (res);
 341                                         } else if (left is UIntConstant){
 342                                                 uint res;
 343
 344                                                 if (ec.ConstantCheckState)
 345                                                         res = checked (((UIntConstant) left).Value +
 346                                                                        ((UIntConstant) right).Value);
 347                                                 else
 348                                                         res = unchecked (((UIntConstant) left).Value +
 349                                                                          ((UIntConstant) right).Value);
 350
 351                                                 return new UIntConstant (res);
 352                                         } else if (left is IntConstant){
 353                                                 int res;
 354
 355                                                 if (ec.ConstantCheckState)
 356                                                         res = checked (((IntConstant) left).Value +
 357                                                                        ((IntConstant) right).Value);
 358                                                 else
 359                                                         res = unchecked (((IntConstant) left).Value +
 360                                                                          ((IntConstant) right).Value);
 361
 362                                                 return new IntConstant (res);
 363                                         } else {
 364                                                 throw new Exception ( "Unexepected input: " + left);
 365                                         }
 366                                 } catch (OverflowException){
 367                                         Error_CompileTimeOverflow (loc);
 368                                 }
 369                                 break;
 370
 371                         case Binary.Operator.Subtraction:
 372                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 373                                 if (left == null || right == null)
 374                                         return null;
 375
 376                                 try {
 377                                         if (left is DoubleConstant){
 378                                                 double res;
 379
 380                                                 if (ec.ConstantCheckState)
 381                                                         res = checked (((DoubleConstant) left).Value -
 382                                                                        ((DoubleConstant) right).Value);
 383                                                 else
 384                                                         res = unchecked (((DoubleConstant) left).Value -
 385                                                                          ((DoubleConstant) right).Value);
 386
 387                                                 return new DoubleConstant (res);
 388                                         } else if (left is FloatConstant){
 389                                                 float res;
 390
 391                                                 if (ec.ConstantCheckState)
 392                                                         res = checked (((FloatConstant) left).Value -
 393                                                                        ((FloatConstant) right).Value);
 394                                                 else
 395                                                         res = unchecked (((FloatConstant) left).Value -
 396                                                                          ((FloatConstant) right).Value);
 397
 398                                                 return new FloatConstant (res);
 399                                         } else if (left is ULongConstant){
 400                                                 ulong res;
 401
 402                                                 if (ec.ConstantCheckState)
 403                                                         res = checked (((ULongConstant) left).Value -
 404                                                                        ((ULongConstant) right).Value);
 405                                                 else
 406                                                         res = unchecked (((ULongConstant) left).Value -
 407                                                                          ((ULongConstant) right).Value);
 408
 409                                                 return new ULongConstant (res);
 410                                         } else if (left is LongConstant){
 411                                                 long res;
 412
 413                                                 if (ec.ConstantCheckState)
 414                                                         res = checked (((LongConstant) left).Value -
 415                                                                        ((LongConstant) right).Value);
 416                                                 else
 417                                                         res = unchecked (((LongConstant) left).Value -
 418                                                                          ((LongConstant) right).Value);
 419
 420                                                 return new LongConstant (res);
 421                                         } else if (left is UIntConstant){
 422                                                 uint res;
 423
 424                                                 if (ec.ConstantCheckState)
 425                                                         res = checked (((UIntConstant) left).Value -
 426                                                                        ((UIntConstant) right).Value);
 427                                                 else
 428                                                         res = unchecked (((UIntConstant) left).Value -
 429                                                                          ((UIntConstant) right).Value);
 430
 431                                                 return new UIntConstant (res);
 432                                         } else if (left is IntConstant){
 433                                                 int res;
 434
 435                                                 if (ec.ConstantCheckState)
 436                                                         res = checked (((IntConstant) left).Value -
 437                                                                        ((IntConstant) right).Value);
 438                                                 else
 439                                                         res = unchecked (((IntConstant) left).Value -
 440                                                                          ((IntConstant) right).Value);
 441
 442                                                 return new IntConstant (res);
 443                                         } else {
 444                                                 throw new Exception ( "Unexepected input: " + left);
 445                                         }
 446                                 } catch (OverflowException){
 447                                         Error_CompileTimeOverflow (loc);
 448                                 }
 449                                 break;
 450
 451                         case Binary.Operator.Multiply:
 452                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 453                                 if (left == null || right == null)
 454                                         return null;
 455
 456                                 try {
 457                                         if (left is DoubleConstant){
 458                                                 double res;
 459
 460                                                 if (ec.ConstantCheckState)
 461                                                         res = checked (((DoubleConstant) left).Value *
 462                                                                        ((DoubleConstant) right).Value);
 463                                                 else
 464                                                         res = unchecked (((DoubleConstant) left).Value *
 465                                                                          ((DoubleConstant) right).Value);
 466
 467                                                 return new DoubleConstant (res);
 468                                         } else if (left is FloatConstant){
 469                                                 float res;
 470
 471                                                 if (ec.ConstantCheckState)
 472                                                         res = checked (((FloatConstant) left).Value *
 473                                                                        ((FloatConstant) right).Value);
 474                                                 else
 475                                                         res = unchecked (((FloatConstant) left).Value *
 476                                                                          ((FloatConstant) right).Value);
 477
 478                                                 return new FloatConstant (res);
 479                                         } else if (left is ULongConstant){
 480                                                 ulong res;
 481
 482                                                 if (ec.ConstantCheckState)
 483                                                         res = checked (((ULongConstant) left).Value *
 484                                                                        ((ULongConstant) right).Value);
 485                                                 else
 486                                                         res = unchecked (((ULongConstant) left).Value *
 487                                                                          ((ULongConstant) right).Value);
 488
 489                                                 return new ULongConstant (res);
 490                                         } else if (left is LongConstant){
 491                                                 long res;
 492
 493                                                 if (ec.ConstantCheckState)
 494                                                         res = checked (((LongConstant) left).Value *
 495                                                                        ((LongConstant) right).Value);
 496                                                 else
 497                                                         res = unchecked (((LongConstant) left).Value *
 498                                                                          ((LongConstant) right).Value);
 499
 500                                                 return new LongConstant (res);
 501                                         } else if (left is UIntConstant){
 502                                                 uint res;
 503
 504                                                 if (ec.ConstantCheckState)
 505                                                         res = checked (((UIntConstant) left).Value *
 506                                                                        ((UIntConstant) right).Value);
 507                                                 else
 508                                                         res = unchecked (((UIntConstant) left).Value *
 509                                                                          ((UIntConstant) right).Value);
 510
 511                                                 return new UIntConstant (res);
 512                                         } else if (left is IntConstant){
 513                                                 int res;
 514
 515                                                 if (ec.ConstantCheckState)
 516                                                         res = checked (((IntConstant) left).Value *
 517                                                                        ((IntConstant) right).Value);
 518                                                 else
 519                                                         res = unchecked (((IntConstant) left).Value *
 520                                                                          ((IntConstant) right).Value);
 521
 522                                                 return new IntConstant (res);
 523                                         } else {
 524                                                 throw new Exception ( "Unexepected input: " + left);
 525                                         }
 526                                 } catch (OverflowException){
 527                                         Error_CompileTimeOverflow (loc);
 528                                 }
 529                                 break;
 530
 531                         case Binary.Operator.Division:
 532                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 533                                 if (left == null || right == null)
 534                                         return null;
 535
 536                                 try {
 537                                         if (left is DoubleConstant){
 538                                                 double res;
 539
 540                                                 if (ec.ConstantCheckState)
 541                                                         res = checked (((DoubleConstant) left).Value /
 542                                                                        ((DoubleConstant) right).Value);
 543                                                 else
 544                                                         res = unchecked (((DoubleConstant) left).Value /
 545                                                                          ((DoubleConstant) right).Value);
 546
 547                                                 return new DoubleConstant (res);
 548                                         } else if (left is FloatConstant){
 549                                                 float res;
 550
 551                                                 if (ec.ConstantCheckState)
 552                                                         res = checked (((FloatConstant) left).Value /
 553                                                                        ((FloatConstant) right).Value);
 554                                                 else
 555                                                         res = unchecked (((FloatConstant) left).Value /
 556                                                                          ((FloatConstant) right).Value);
 557
 558                                                 return new FloatConstant (res);
 559                                         } else if (left is ULongConstant){
 560                                                 ulong res;
 561
 562                                                 if (ec.ConstantCheckState)
 563                                                         res = checked (((ULongConstant) left).Value /
 564                                                                        ((ULongConstant) right).Value);
 565                                                 else
 566                                                         res = unchecked (((ULongConstant) left).Value /
 567                                                                          ((ULongConstant) right).Value);
 568
 569                                                 return new ULongConstant (res);
 570                                         } else if (left is LongConstant){
 571                                                 long res;
 572
 573                                                 if (ec.ConstantCheckState)
 574                                                         res = checked (((LongConstant) left).Value /
 575                                                                        ((LongConstant) right).Value);
 576                                                 else
 577                                                         res = unchecked (((LongConstant) left).Value /
 578                                                                          ((LongConstant) right).Value);
 579
 580                                                 return new LongConstant (res);
 581                                         } else if (left is UIntConstant){
 582                                                 uint res;
 583
 584                                                 if (ec.ConstantCheckState)
 585                                                         res = checked (((UIntConstant) left).Value /
 586                                                                        ((UIntConstant) right).Value);
 587                                                 else
 588                                                         res = unchecked (((UIntConstant) left).Value /
 589                                                                          ((UIntConstant) right).Value);
 590
 591                                                 return new UIntConstant (res);
 592                                         } else if (left is IntConstant){
 593                                                 int res;
 594
 595                                                 if (ec.ConstantCheckState)
 596                                                         res = checked (((IntConstant) left).Value /
 597                                                                        ((IntConstant) right).Value);
 598                                                 else
 599                                                         res = unchecked (((IntConstant) left).Value /
 600                                                                          ((IntConstant) right).Value);
 601
 602                                                 return new IntConstant (res);
 603                                         } else {
 604                                                 throw new Exception ( "Unexepected input: " + left);
 605                                         }
 606                                 } catch (OverflowException){
 607                                         Error_CompileTimeOverflow (loc);
 608                                 }
 609                                 break;
 610
 611                         case Binary.Operator.Modulus:
 612                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 613                                 if (left == null || right == null)
 614                                         return null;
 615
 616                                 try {
 617                                         if (left is DoubleConstant){
 618                                                 double res;
 619
 620                                                 if (ec.ConstantCheckState)
 621                                                         res = checked (((DoubleConstant) left).Value %
 622                                                                        ((DoubleConstant) right).Value);
 623                                                 else
 624                                                         res = unchecked (((DoubleConstant) left).Value %
 625                                                                          ((DoubleConstant) right).Value);
 626
 627                                                 return new DoubleConstant (res);
 628                                         } else if (left is FloatConstant){
 629                                                 float res;
 630
 631                                                 if (ec.ConstantCheckState)
 632                                                         res = checked (((FloatConstant) left).Value %
 633                                                                        ((FloatConstant) right).Value);
 634                                                 else
 635                                                         res = unchecked (((FloatConstant) left).Value %
 636                                                                          ((FloatConstant) right).Value);
 637
 638                                                 return new FloatConstant (res);
 639                                         } else if (left is ULongConstant){
 640                                                 ulong res;
 641
 642                                                 if (ec.ConstantCheckState)
 643                                                         res = checked (((ULongConstant) left).Value %
 644                                                                        ((ULongConstant) right).Value);
 645                                                 else
 646                                                         res = unchecked (((ULongConstant) left).Value %
 647                                                                          ((ULongConstant) right).Value);
 648
 649                                                 return new ULongConstant (res);
 650                                         } else if (left is LongConstant){
 651                                                 long res;
 652
 653                                                 if (ec.ConstantCheckState)
 654                                                         res = checked (((LongConstant) left).Value %
 655                                                                        ((LongConstant) right).Value);
 656                                                 else
 657                                                         res = unchecked (((LongConstant) left).Value %
 658                                                                          ((LongConstant) right).Value);
 659
 660                                                 return new LongConstant (res);
 661                                         } else if (left is UIntConstant){
 662                                                 uint res;
 663
 664                                                 if (ec.ConstantCheckState)
 665                                                         res = checked (((UIntConstant) left).Value %
 666                                                                        ((UIntConstant) right).Value);
 667                                                 else
 668                                                         res = unchecked (((UIntConstant) left).Value %
 669                                                                          ((UIntConstant) right).Value);
 670
 671                                                 return new UIntConstant (res);
 672                                         } else if (left is IntConstant){
 673                                                 int res;
 674
 675                                                 if (ec.ConstantCheckState)
 676                                                         res = checked (((IntConstant) left).Value %
 677                                                                        ((IntConstant) right).Value);
 678                                                 else
 679                                                         res = unchecked (((IntConstant) left).Value %
 680                                                                          ((IntConstant) right).Value);
 681
 682                                                 return new IntConstant (res);
 683                                         } else {
 684                                                 throw new Exception ( "Unexepected input: " + left);
 685                                         }
 686                                 } catch (OverflowException){
 687                                         Error_CompileTimeOverflow (loc);
 688                                 }
 689                                 break;
 690
 691                                 //
 692                                 // There is no overflow checking on left shift
 693                                 //
 694                         case Binary.Operator.LeftShift:
 695                                 IntConstant ic = right.ToInt (loc);
 696                                 if (ic == null){
 697                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 698                                         return null;
 699                                 }
 700                                 int lshift_val = ic.Value;
 701
 702                                 IntConstant lic;
 703                                 if ((lic = left.ConvertToInt ()) != null)
 704                                         return new IntConstant (lic.Value << lshift_val);
 705
 706                                 UIntConstant luic;
 707                                 if ((luic = left.ConvertToUInt ()) != null)
 708                                         return new UIntConstant (luic.Value << lshift_val);
 709
 710                                 LongConstant llc;
 711                                 if ((llc = left.ConvertToLong ()) != null)
 712                                         return new LongConstant (llc.Value << lshift_val);
 713
 714                                 ULongConstant lulc;
 715                                 if ((lulc = left.ConvertToULong ()) != null)
 716                                         return new ULongConstant (lulc.Value << lshift_val);
 717
 718                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 719                                 break;
 720
 721                                 //
 722                                 // There is no overflow checking on right shift
 723                                 //
 724                         case Binary.Operator.RightShift:
 725                                 IntConstant sic = right.ToInt (loc);
 726                                 if (sic == null){
 727                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 728                                         return null;
 729                                 }
 730                                 int rshift_val = sic.Value;
 731
 732                                 IntConstant ric;
 733                                 if ((ric = left.ConvertToInt ()) != null)
 734                                         return new IntConstant (ric.Value >> rshift_val);
 735
 736                                 UIntConstant ruic;
 737                                 if ((ruic = left.ConvertToUInt ()) != null)
 738                                         return new UIntConstant (ruic.Value >> rshift_val);
 739
 740                                 LongConstant rlc;
 741                                 if ((rlc = left.ConvertToLong ()) != null)
 742                                         return new LongConstant (rlc.Value >> rshift_val);
 743
 744                                 ULongConstant rulc;
 745                                 if ((rulc = left.ConvertToULong ()) != null)
 746                                         return new ULongConstant (rulc.Value >> rshift_val);
 747
 748                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 749                                 break;
 750
 751                         case Binary.Operator.LogicalAnd:
 752                                 if (left is BoolConstant && right is BoolConstant){
 753                                         return new BoolConstant (
 754                                                 ((BoolConstant) left).Value &&
 755                                                 ((BoolConstant) right).Value);
 756                                 }
 757                                 break;
 758
 759                         case Binary.Operator.LogicalOr:
 760                                 if (left is BoolConstant && right is BoolConstant){
 761                                         return new BoolConstant (
 762                                                 ((BoolConstant) left).Value ||
 763                                                 ((BoolConstant) right).Value);
 764                                 }
 765                                 break;
 766
 767                         case Binary.Operator.Equality:
 768                                 if (left is BoolConstant && right is BoolConstant){
 769                                         return new BoolConstant (
 770                                                 ((BoolConstant) left).Value ==
 771                                                 ((BoolConstant) right).Value);
 772
 773                                 }
 774                                 if (left is StringConstant && right is StringConstant){
 775                                         return new BoolConstant (
 776                                                 ((StringConstant) left).Value ==
 777                                                 ((StringConstant) right).Value);
 778
 779                                 }
 780
 781                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 782                                 if (left == null || right == null)
 783                                         return null;
 784
 785                                 bool_res = false;
 786                                 if (left is DoubleConstant)
 787                                         bool_res = ((DoubleConstant) left).Value ==
 788                                                 ((DoubleConstant) right).Value;
 789                                 else if (left is FloatConstant)
 790                                         bool_res = ((FloatConstant) left).Value ==
 791                                                 ((FloatConstant) right).Value;
 792                                 else if (left is ULongConstant)
 793                                         bool_res = ((ULongConstant) left).Value ==
 794                                                 ((ULongConstant) right).Value;
 795                                 else if (left is LongConstant)
 796                                         bool_res = ((LongConstant) left).Value ==
 797                                                 ((LongConstant) right).Value;
 798                                 else if (left is UIntConstant)
 799                                         bool_res = ((UIntConstant) left).Value ==
 800                                                 ((UIntConstant) right).Value;
 801                                 else if (left is IntConstant)
 802                                         bool_res = ((IntConstant) left).Value ==
 803                                                 ((IntConstant) right).Value;
 804                                 else
 805                                         return null;
 806
 807                                 return new BoolConstant (bool_res);
 808
 809                         case Binary.Operator.Inequality:
 810                                 if (left is BoolConstant && right is BoolConstant){
 811                                         return new BoolConstant (
 812                                                 ((BoolConstant) left).Value !=
 813                                                 ((BoolConstant) right).Value);
 814                                 }
 815                                 if (left is StringConstant && right is StringConstant){
 816                                         return new BoolConstant (
 817                                                 ((StringConstant) left).Value !=
 818                                                 ((StringConstant) right).Value);
 819
 820                                 }
 821                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 822                                 if (left == null || right == null)
 823                                         return null;
 824
 825                                 bool_res = false;
 826                                 if (left is DoubleConstant)
 827                                         bool_res = ((DoubleConstant) left).Value !=
 828                                                 ((DoubleConstant) right).Value;
 829                                 else if (left is FloatConstant)
 830                                         bool_res = ((FloatConstant) left).Value !=
 831                                                 ((FloatConstant) right).Value;
 832                                 else if (left is ULongConstant)
 833                                         bool_res = ((ULongConstant) left).Value !=
 834                                                 ((ULongConstant) right).Value;
 835                                 else if (left is LongConstant)
 836                                         bool_res = ((LongConstant) left).Value !=
 837                                                 ((LongConstant) right).Value;
 838                                 else if (left is UIntConstant)
 839                                         bool_res = ((UIntConstant) left).Value !=
 840                                                 ((UIntConstant) right).Value;
 841                                 else if (left is IntConstant)
 842                                         bool_res = ((IntConstant) left).Value !=
 843                                                 ((IntConstant) right).Value;
 844                                 else
 845                                         return null;
 846
 847                                 return new BoolConstant (bool_res);
 848
 849                         case Binary.Operator.LessThan:
 850                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 851                                 if (left == null || right == null)
 852                                         return null;
 853
 854                                 bool_res = false;
 855                                 if (left is DoubleConstant)
 856                                         bool_res = ((DoubleConstant) left).Value <
 857                                                 ((DoubleConstant) right).Value;
 858                                 else if (left is FloatConstant)
 859                                         bool_res = ((FloatConstant) left).Value <
 860                                                 ((FloatConstant) right).Value;
 861                                 else if (left is ULongConstant)
 862                                         bool_res = ((ULongConstant) left).Value <
 863                                                 ((ULongConstant) right).Value;
 864                                 else if (left is LongConstant)
 865                                         bool_res = ((LongConstant) left).Value <
 866                                                 ((LongConstant) right).Value;
 867                                 else if (left is UIntConstant)
 868                                         bool_res = ((UIntConstant) left).Value <
 869                                                 ((UIntConstant) right).Value;
 870                                 else if (left is IntConstant)
 871                                         bool_res = ((IntConstant) left).Value <
 872                                                 ((IntConstant) right).Value;
 873                                 else
 874                                         return null;
 875
 876                                 return new BoolConstant (bool_res);
 877
 878                         case Binary.Operator.GreaterThan:
 879                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 880                                 if (left == null || right == null)
 881                                         return null;
 882
 883                                 bool_res = false;
 884                                 if (left is DoubleConstant)
 885                                         bool_res = ((DoubleConstant) left).Value >
 886                                                 ((DoubleConstant) right).Value;
 887                                 else if (left is FloatConstant)
 888                                         bool_res = ((FloatConstant) left).Value >
 889                                                 ((FloatConstant) right).Value;
 890                                 else if (left is ULongConstant)
 891                                         bool_res = ((ULongConstant) left).Value >
 892                                                 ((ULongConstant) right).Value;
 893                                 else if (left is LongConstant)
 894                                         bool_res = ((LongConstant) left).Value >
 895                                                 ((LongConstant) right).Value;
 896                                 else if (left is UIntConstant)
 897                                         bool_res = ((UIntConstant) left).Value >
 898                                                 ((UIntConstant) right).Value;
 899                                 else if (left is IntConstant)
 900                                         bool_res = ((IntConstant) left).Value >
 901                                                 ((IntConstant) right).Value;
 902                                 else
 903                                         return null;
 904
 905                                 return new BoolConstant (bool_res);
 906
 907                         case Binary.Operator.GreaterThanOrEqual:
 908                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 909                                 if (left == null || right == null)
 910                                         return null;
 911
 912                                 bool_res = false;
 913                                 if (left is DoubleConstant)
 914                                         bool_res = ((DoubleConstant) left).Value >=
 915                                                 ((DoubleConstant) right).Value;
 916                                 else if (left is FloatConstant)
 917                                         bool_res = ((FloatConstant) left).Value >=
 918                                                 ((FloatConstant) right).Value;
 919                                 else if (left is ULongConstant)
 920                                         bool_res = ((ULongConstant) left).Value >=
 921                                                 ((ULongConstant) right).Value;
 922                                 else if (left is LongConstant)
 923                                         bool_res = ((LongConstant) left).Value >=
 924                                                 ((LongConstant) right).Value;
 925                                 else if (left is UIntConstant)
 926                                         bool_res = ((UIntConstant) left).Value >=
 927                                                 ((UIntConstant) right).Value;
 928                                 else if (left is IntConstant)
 929                                         bool_res = ((IntConstant) left).Value >=
 930                                                 ((IntConstant) right).Value;
 931                                 else
 932                                         return null;
 933
 934                                 return new BoolConstant (bool_res);
 935
 936                         case Binary.Operator.LessThanOrEqual:
 937                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 938                                 if (left == null || right == null)
 939                                         return null;
 940
 941                                 bool_res = false;
 942                                 if (left is DoubleConstant)
 943                                         bool_res = ((DoubleConstant) left).Value <=
 944                                                 ((DoubleConstant) right).Value;
 945                                 else if (left is FloatConstant)
 946                                         bool_res = ((FloatConstant) left).Value <=
 947                                                 ((FloatConstant) right).Value;
 948                                 else if (left is ULongConstant)
 949                                         bool_res = ((ULongConstant) left).Value <=
 950                                                 ((ULongConstant) right).Value;
 951                                 else if (left is LongConstant)
 952                                         bool_res = ((LongConstant) left).Value <=
 953                                                 ((LongConstant) right).Value;
 954                                 else if (left is UIntConstant)
 955                                         bool_res = ((UIntConstant) left).Value <=
 956                                                 ((UIntConstant) right).Value;
 957                                 else if (left is IntConstant)
 958                                         bool_res = ((IntConstant) left).Value <=
 959                                                 ((IntConstant) right).Value;
 960                                 else
 961                                         return null;
 962
 963                                 return new BoolConstant (bool_res);
 964                         }
 965
 966                         return null;
 967                 }
 968         }
 969 }