mcs/mbas/cfold.cs

   1 //
   2 // cfold.cs: Constant Folding
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2002 Ximian, Inc.
   8 //
   9
  10 using System;
  11
  12 namespace Mono.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 WRONG
  74                                 if (other is SByteConstant || other is ShortConstant ||
  75                                     other is IntConstant || other is LongConstant){
  76                                         Binary.Error_OperatorAmbiguous
  77                                                 (loc, oper, other.Type, match.Type);
  78                                         left = null;
  79                                         right = null;
  80                                 }
  81 #endif
  82                                 return;
  83                         } else if (left is LongConstant || right is LongConstant){
  84                                 //
  85                                 // If either operand is of type long, the other operand is converted
  86                                 // to type long.
  87                                 //
  88                                 if (!(left is LongConstant))
  89                                         left = left.ToLong (loc);
  90                                 else if (!(right is LongConstant))
  91                                         right = right.ToLong (loc);
  92                                 return;
  93                         } else if (left is UIntConstant || right is UIntConstant){
  94                                 //
  95                                 // If either operand is of type uint, and the other
  96                                 // operand is of type sbyte, short or int, othe operands are
  97                                 // converted to type long.
  98                                 //
  99                                 if (!(left is UIntConstant))
 100                                         left = left.ToUInt (loc);
 101                                 else if (!(right is UIntConstant))
 102                                         right = right.ToUInt (loc);
 103                                 return;
 104                         } else {
 105                                 //
 106                                 // Force conversions to int32
 107                                 //
 108                                 if (!(left is IntConstant))
 109                                         left = left.ToInt (loc);
 110                                 if (!(right is IntConstant))
 111                                         right = right.ToInt (loc);
 112                         }
 113                         return;
 114                 }
 115
 116                 static void Error_CompileTimeOverflow (Location loc)
 117                 {
 118                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 119                 }
 120
 121                 /// <summary>
 122                 ///   Constant expression folder for binary operations.
 123                 ///
 124                 ///   Returns null if the expression can not be folded.
 125                 /// </summary>
 126                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 127                                                      Constant left, Constant right, Location loc)
 128                 {
 129                         Type lt = left.Type;
 130                         Type rt = right.Type;
 131                         Type result_type = null;
 132                         bool bool_res;
 133
 134                         //
 135                         // Enumerator folding
 136                         //
 137                         if (rt == lt && left is EnumConstant)
 138                                 result_type = lt;
 139
 140                         //
 141                         // During an enum evaluation, we need to unwrap enumerations
 142                         //
 143                         if (ec.InEnumContext){
 144                                 if (left is EnumConstant)
 145                                         left = ((EnumConstant) left).Child;
 146
 147                                 if (right is EnumConstant)
 148                                         right = ((EnumConstant) right).Child;
 149                         }
 150
 151                         switch (oper){
 152                         case Binary.Operator.BitwiseOr:
 153                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 154                                 if (left == null || right == null)
 155                                         return null;
 156
 157                                 if (left is IntConstant){
 158                                         IntConstant v;
 159                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 160
 161                                         v = new IntConstant (res);
 162                                         if (result_type == null)
 163                                                 return v;
 164                                         else
 165                                                 return new EnumConstant (v, result_type);
 166                                 } else if (left is UIntConstant){
 167                                         UIntConstant v;
 168                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 169
 170                                         v = new UIntConstant (res);
 171                                         if (result_type == null)
 172                                                 return v;
 173                                         else
 174                                                 return new EnumConstant (v, result_type);
 175                                 } else if (left is LongConstant){
 176                                         LongConstant v;
 177                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 178
 179                                         v = new LongConstant (res);
 180                                         if (result_type == null)
 181                                                 return v;
 182                                         else
 183                                                 return new EnumConstant (v, result_type);
 184                                 } else if (left is ULongConstant){
 185                                         ULongConstant v;
 186                                         ulong res = ((ULongConstant)left).Value |
 187                                                 ((ULongConstant)right).Value;
 188
 189                                         v = new ULongConstant (res);
 190                                         if (result_type == null)
 191                                                 return v;
 192                                         else
 193                                                 return new EnumConstant (v, result_type);
 194                                 }
 195                                 break;
 196
 197                         case Binary.Operator.BitwiseAnd:
 198                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 199                                 if (left == null || right == null)
 200                                         return null;
 201
 202                                 if (left is IntConstant){
 203                                         IntConstant v;
 204                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 205
 206                                         v = new IntConstant (res);
 207                                         if (result_type == null)
 208                                                 return v;
 209                                         else
 210                                                 return new EnumConstant (v, result_type);
 211                                 } else if (left is UIntConstant){
 212                                         UIntConstant v;
 213                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 214
 215                                         v = new UIntConstant (res);
 216                                         if (result_type == null)
 217                                                 return v;
 218                                         else
 219                                                 return new EnumConstant (v, result_type);
 220                                 } else if (left is LongConstant){
 221                                         LongConstant v;
 222                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 223
 224                                         v = new LongConstant (res);
 225                                         if (result_type == null)
 226                                                 return v;
 227                                         else
 228                                                 return new EnumConstant (v, result_type);
 229                                 } else if (left is ULongConstant){
 230                                         ULongConstant v;
 231                                         ulong res = ((ULongConstant)left).Value &
 232                                                 ((ULongConstant)right).Value;
 233
 234                                         v = new ULongConstant (res);
 235                                         if (result_type == null)
 236                                                 return v;
 237                                         else
 238                                                 return new EnumConstant (v, result_type);
 239                                 }
 240                                 break;
 241
 242                         case Binary.Operator.ExclusiveOr:
 243                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 244                                 if (left == null || right == null)
 245                                         return null;
 246
 247                                 if (left is IntConstant){
 248                                         IntConstant v;
 249                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 250
 251                                         v = new IntConstant (res);
 252                                         if (result_type == null)
 253                                                 return v;
 254                                         else
 255                                                 return new EnumConstant (v, result_type);
 256                                 } else if (left is UIntConstant){
 257                                         UIntConstant v;
 258                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 259
 260                                         v = new UIntConstant (res);
 261                                         if (result_type == null)
 262                                                 return v;
 263                                         else
 264                                                 return new EnumConstant (v, result_type);
 265                                 } else if (left is LongConstant){
 266                                         LongConstant v;
 267                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 268
 269                                         v = new LongConstant (res);
 270                                         if (result_type == null)
 271                                                 return v;
 272                                         else
 273                                                 return new EnumConstant (v, result_type);
 274                                 } else if (left is ULongConstant){
 275                                         ULongConstant v;
 276                                         ulong res = ((ULongConstant)left).Value ^
 277                                                 ((ULongConstant)right).Value;
 278
 279                                         v = new ULongConstant (res);
 280                                         if (result_type == null)
 281                                                 return v;
 282                                         else
 283                                                 return new EnumConstant (v, result_type);
 284                                 }
 285                                 break;
 286
 287                         case Binary.Operator.Addition:
 288                                 Constant result;
 289                                 bool left_is_string = left is StringConstant;
 290                                 bool right_is_string = right is StringConstant;
 291
 292                                 //
 293                                 // If both sides are strings, then concatenate, if
 294                                 // one is a string, and the other is not, then defer
 295                                 // to runtime concatenation
 296                                 //
 297                                 if (left_is_string || right_is_string){
 298                                         if (left_is_string && right_is_string)
 299                                                 return new StringConstant (
 300                                                         ((StringConstant) left).Value +
 301                                                         ((StringConstant) right).Value);
 302
 303                                         return null;
 304                                 }
 305
 306                                 //
 307                                 // handle "E operator + (E x, U y)"
 308                                 // handle "E operator + (Y y, E x)"
 309                                 //
 310                                 // note that E operator + (E x, E y) is invalid
 311                                 //
 312                                 Type wrap_as = null;
 313                                 if (left is EnumConstant){
 314                                         if (right is EnumConstant){
 315                                                 return null;
 316                                         }
 317                                         if (((EnumConstant) left).Child.Type != right.Type)
 318                                                 return null;
 319
 320                                         wrap_as = left.Type;
 321                                 } else if (right is EnumConstant){
 322                                         if (((EnumConstant) right).Child.Type != left.Type)
 323                                                 return null;
 324                                         wrap_as = right.Type;
 325                                 }
 326
 327                                 result = null;
 328                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 329                                 if (left == null || right == null)
 330                                         return null;
 331
 332                                 try {
 333                                         if (left is DoubleConstant){
 334                                                 double res;
 335
 336                                                 if (ec.ConstantCheckState)
 337                                                         res = checked (((DoubleConstant) left).Value +
 338                                                                        ((DoubleConstant) right).Value);
 339                                                 else
 340                                                         res = unchecked (((DoubleConstant) left).Value +
 341                                                                          ((DoubleConstant) right).Value);
 342
 343                                                 result = new DoubleConstant (res);
 344                                         } else if (left is FloatConstant){
 345                                                 float res;
 346
 347                                                 if (ec.ConstantCheckState)
 348                                                         res = checked (((FloatConstant) left).Value +
 349                                                                        ((FloatConstant) right).Value);
 350                                                 else
 351                                                         res = unchecked (((FloatConstant) left).Value +
 352                                                                          ((FloatConstant) right).Value);
 353
 354                                                 result = new FloatConstant (res);
 355                                         } else if (left is ULongConstant){
 356                                                 ulong res;
 357
 358                                                 if (ec.ConstantCheckState)
 359                                                         res = checked (((ULongConstant) left).Value +
 360                                                                        ((ULongConstant) right).Value);
 361                                                 else
 362                                                         res = unchecked (((ULongConstant) left).Value +
 363                                                                          ((ULongConstant) right).Value);
 364
 365                                                 result = new ULongConstant (res);
 366                                         } else if (left is LongConstant){
 367                                                 long res;
 368
 369                                                 if (ec.ConstantCheckState)
 370                                                         res = checked (((LongConstant) left).Value +
 371                                                                        ((LongConstant) right).Value);
 372                                                 else
 373                                                         res = unchecked (((LongConstant) left).Value +
 374                                                                          ((LongConstant) right).Value);
 375
 376                                                 result = new LongConstant (res);
 377                                         } else if (left is UIntConstant){
 378                                                 uint res;
 379
 380                                                 if (ec.ConstantCheckState)
 381                                                         res = checked (((UIntConstant) left).Value +
 382                                                                        ((UIntConstant) right).Value);
 383                                                 else
 384                                                         res = unchecked (((UIntConstant) left).Value +
 385                                                                          ((UIntConstant) right).Value);
 386
 387                                                 result = new UIntConstant (res);
 388                                         } else if (left is IntConstant){
 389                                                 int res;
 390
 391                                                 if (ec.ConstantCheckState)
 392                                                         res = checked (((IntConstant) left).Value +
 393                                                                        ((IntConstant) right).Value);
 394                                                 else
 395                                                         res = unchecked (((IntConstant) left).Value +
 396                                                                          ((IntConstant) right).Value);
 397
 398                                                 result = new IntConstant (res);
 399                                         } else {
 400                                                 throw new Exception ( "Unexepected input: " + left);
 401                                         }
 402                                 } catch (OverflowException){
 403                                         Error_CompileTimeOverflow (loc);
 404                                 }
 405
 406                                 if (wrap_as != null)
 407                                         return new EnumConstant (result, wrap_as);
 408                                 else
 409                                         return result;
 410
 411                         case Binary.Operator.Subtraction:
 412                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 413                                 if (left == null || right == null)
 414                                         return null;
 415
 416                                 try {
 417                                         if (left is DoubleConstant){
 418                                                 double res;
 419
 420                                                 if (ec.ConstantCheckState)
 421                                                         res = checked (((DoubleConstant) left).Value -
 422                                                                        ((DoubleConstant) right).Value);
 423                                                 else
 424                                                         res = unchecked (((DoubleConstant) left).Value -
 425                                                                          ((DoubleConstant) right).Value);
 426
 427                                                 return new DoubleConstant (res);
 428                                         } else if (left is FloatConstant){
 429                                                 float res;
 430
 431                                                 if (ec.ConstantCheckState)
 432                                                         res = checked (((FloatConstant) left).Value -
 433                                                                        ((FloatConstant) right).Value);
 434                                                 else
 435                                                         res = unchecked (((FloatConstant) left).Value -
 436                                                                          ((FloatConstant) right).Value);
 437
 438                                                 return new FloatConstant (res);
 439                                         } else if (left is ULongConstant){
 440                                                 ulong res;
 441
 442                                                 if (ec.ConstantCheckState)
 443                                                         res = checked (((ULongConstant) left).Value -
 444                                                                        ((ULongConstant) right).Value);
 445                                                 else
 446                                                         res = unchecked (((ULongConstant) left).Value -
 447                                                                          ((ULongConstant) right).Value);
 448
 449                                                 return new ULongConstant (res);
 450                                         } else if (left is LongConstant){
 451                                                 long res;
 452
 453                                                 if (ec.ConstantCheckState)
 454                                                         res = checked (((LongConstant) left).Value -
 455                                                                        ((LongConstant) right).Value);
 456                                                 else
 457                                                         res = unchecked (((LongConstant) left).Value -
 458                                                                          ((LongConstant) right).Value);
 459
 460                                                 return new LongConstant (res);
 461                                         } else if (left is UIntConstant){
 462                                                 uint res;
 463
 464                                                 if (ec.ConstantCheckState)
 465                                                         res = checked (((UIntConstant) left).Value -
 466                                                                        ((UIntConstant) right).Value);
 467                                                 else
 468                                                         res = unchecked (((UIntConstant) left).Value -
 469                                                                          ((UIntConstant) right).Value);
 470
 471                                                 return new UIntConstant (res);
 472                                         } else if (left is IntConstant){
 473                                                 int res;
 474
 475                                                 if (ec.ConstantCheckState)
 476                                                         res = checked (((IntConstant) left).Value -
 477                                                                        ((IntConstant) right).Value);
 478                                                 else
 479                                                         res = unchecked (((IntConstant) left).Value -
 480                                                                          ((IntConstant) right).Value);
 481
 482                                                 return new IntConstant (res);
 483                                         } else {
 484                                                 throw new Exception ( "Unexepected input: " + left);
 485                                         }
 486                                 } catch (OverflowException){
 487                                         Error_CompileTimeOverflow (loc);
 488                                 }
 489                                 break;
 490
 491                         case Binary.Operator.Multiply:
 492                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 493                                 if (left == null || right == null)
 494                                         return null;
 495
 496                                 try {
 497                                         if (left is DoubleConstant){
 498                                                 double res;
 499
 500                                                 if (ec.ConstantCheckState)
 501                                                         res = checked (((DoubleConstant) left).Value *
 502                                                                        ((DoubleConstant) right).Value);
 503                                                 else
 504                                                         res = unchecked (((DoubleConstant) left).Value *
 505                                                                          ((DoubleConstant) right).Value);
 506
 507                                                 return new DoubleConstant (res);
 508                                         } else if (left is FloatConstant){
 509                                                 float res;
 510
 511                                                 if (ec.ConstantCheckState)
 512                                                         res = checked (((FloatConstant) left).Value *
 513                                                                        ((FloatConstant) right).Value);
 514                                                 else
 515                                                         res = unchecked (((FloatConstant) left).Value *
 516                                                                          ((FloatConstant) right).Value);
 517
 518                                                 return new FloatConstant (res);
 519                                         } else if (left is ULongConstant){
 520                                                 ulong res;
 521
 522                                                 if (ec.ConstantCheckState)
 523                                                         res = checked (((ULongConstant) left).Value *
 524                                                                        ((ULongConstant) right).Value);
 525                                                 else
 526                                                         res = unchecked (((ULongConstant) left).Value *
 527                                                                          ((ULongConstant) right).Value);
 528
 529                                                 return new ULongConstant (res);
 530                                         } else if (left is LongConstant){
 531                                                 long res;
 532
 533                                                 if (ec.ConstantCheckState)
 534                                                         res = checked (((LongConstant) left).Value *
 535                                                                        ((LongConstant) right).Value);
 536                                                 else
 537                                                         res = unchecked (((LongConstant) left).Value *
 538                                                                          ((LongConstant) right).Value);
 539
 540                                                 return new LongConstant (res);
 541                                         } else if (left is UIntConstant){
 542                                                 uint res;
 543
 544                                                 if (ec.ConstantCheckState)
 545                                                         res = checked (((UIntConstant) left).Value *
 546                                                                        ((UIntConstant) right).Value);
 547                                                 else
 548                                                         res = unchecked (((UIntConstant) left).Value *
 549                                                                          ((UIntConstant) right).Value);
 550
 551                                                 return new UIntConstant (res);
 552                                         } else if (left is IntConstant){
 553                                                 int res;
 554
 555                                                 if (ec.ConstantCheckState)
 556                                                         res = checked (((IntConstant) left).Value *
 557                                                                        ((IntConstant) right).Value);
 558                                                 else
 559                                                         res = unchecked (((IntConstant) left).Value *
 560                                                                          ((IntConstant) right).Value);
 561
 562                                                 return new IntConstant (res);
 563                                         } else {
 564                                                 throw new Exception ( "Unexepected input: " + left);
 565                                         }
 566                                 } catch (OverflowException){
 567                                         Error_CompileTimeOverflow (loc);
 568                                 }
 569                                 break;
 570
 571                         case Binary.Operator.Division:
 572                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 573                                 if (left == null || right == null)
 574                                         return null;
 575
 576                                 try {
 577                                         if (left is DoubleConstant){
 578                                                 double res;
 579
 580                                                 if (ec.ConstantCheckState)
 581                                                         res = checked (((DoubleConstant) left).Value /
 582                                                                        ((DoubleConstant) right).Value);
 583                                                 else
 584                                                         res = unchecked (((DoubleConstant) left).Value /
 585                                                                          ((DoubleConstant) right).Value);
 586
 587                                                 return new DoubleConstant (res);
 588                                         } else if (left is FloatConstant){
 589                                                 float res;
 590
 591                                                 if (ec.ConstantCheckState)
 592                                                         res = checked (((FloatConstant) left).Value /
 593                                                                        ((FloatConstant) right).Value);
 594                                                 else
 595                                                         res = unchecked (((FloatConstant) left).Value /
 596                                                                          ((FloatConstant) right).Value);
 597
 598                                                 return new FloatConstant (res);
 599                                         } else if (left is ULongConstant){
 600                                                 ulong res;
 601
 602                                                 if (ec.ConstantCheckState)
 603                                                         res = checked (((ULongConstant) left).Value /
 604                                                                        ((ULongConstant) right).Value);
 605                                                 else
 606                                                         res = unchecked (((ULongConstant) left).Value /
 607                                                                          ((ULongConstant) right).Value);
 608
 609                                                 return new ULongConstant (res);
 610                                         } else if (left is LongConstant){
 611                                                 long res;
 612
 613                                                 if (ec.ConstantCheckState)
 614                                                         res = checked (((LongConstant) left).Value /
 615                                                                        ((LongConstant) right).Value);
 616                                                 else
 617                                                         res = unchecked (((LongConstant) left).Value /
 618                                                                          ((LongConstant) right).Value);
 619
 620                                                 return new LongConstant (res);
 621                                         } else if (left is UIntConstant){
 622                                                 uint res;
 623
 624                                                 if (ec.ConstantCheckState)
 625                                                         res = checked (((UIntConstant) left).Value /
 626                                                                        ((UIntConstant) right).Value);
 627                                                 else
 628                                                         res = unchecked (((UIntConstant) left).Value /
 629                                                                          ((UIntConstant) right).Value);
 630
 631                                                 return new UIntConstant (res);
 632                                         } else if (left is IntConstant){
 633                                                 int res;
 634
 635                                                 if (ec.ConstantCheckState)
 636                                                         res = checked (((IntConstant) left).Value /
 637                                                                        ((IntConstant) right).Value);
 638                                                 else
 639                                                         res = unchecked (((IntConstant) left).Value /
 640                                                                          ((IntConstant) right).Value);
 641
 642                                                 return new IntConstant (res);
 643                                         } else {
 644                                                 throw new Exception ( "Unexepected input: " + left);
 645                                         }
 646                                 } catch (OverflowException){
 647                                         Error_CompileTimeOverflow (loc);
 648
 649                                 } catch (DivideByZeroException) {
 650                                         Report.Error (020, loc, "Division by constant zero");
 651                                 }
 652
 653                                 break;
 654
 655                         case Binary.Operator.Modulus:
 656                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 657                                 if (left == null || right == null)
 658                                         return null;
 659
 660                                 try {
 661                                         if (left is DoubleConstant){
 662                                                 double res;
 663
 664                                                 if (ec.ConstantCheckState)
 665                                                         res = checked (((DoubleConstant) left).Value %
 666                                                                        ((DoubleConstant) right).Value);
 667                                                 else
 668                                                         res = unchecked (((DoubleConstant) left).Value %
 669                                                                          ((DoubleConstant) right).Value);
 670
 671                                                 return new DoubleConstant (res);
 672                                         } else if (left is FloatConstant){
 673                                                 float res;
 674
 675                                                 if (ec.ConstantCheckState)
 676                                                         res = checked (((FloatConstant) left).Value %
 677                                                                        ((FloatConstant) right).Value);
 678                                                 else
 679                                                         res = unchecked (((FloatConstant) left).Value %
 680                                                                          ((FloatConstant) right).Value);
 681
 682                                                 return new FloatConstant (res);
 683                                         } else if (left is ULongConstant){
 684                                                 ulong res;
 685
 686                                                 if (ec.ConstantCheckState)
 687                                                         res = checked (((ULongConstant) left).Value %
 688                                                                        ((ULongConstant) right).Value);
 689                                                 else
 690                                                         res = unchecked (((ULongConstant) left).Value %
 691                                                                          ((ULongConstant) right).Value);
 692
 693                                                 return new ULongConstant (res);
 694                                         } else if (left is LongConstant){
 695                                                 long res;
 696
 697                                                 if (ec.ConstantCheckState)
 698                                                         res = checked (((LongConstant) left).Value %
 699                                                                        ((LongConstant) right).Value);
 700                                                 else
 701                                                         res = unchecked (((LongConstant) left).Value %
 702                                                                          ((LongConstant) right).Value);
 703
 704                                                 return new LongConstant (res);
 705                                         } else if (left is UIntConstant){
 706                                                 uint res;
 707
 708                                                 if (ec.ConstantCheckState)
 709                                                         res = checked (((UIntConstant) left).Value %
 710                                                                        ((UIntConstant) right).Value);
 711                                                 else
 712                                                         res = unchecked (((UIntConstant) left).Value %
 713                                                                          ((UIntConstant) right).Value);
 714
 715                                                 return new UIntConstant (res);
 716                                         } else if (left is IntConstant){
 717                                                 int res;
 718
 719                                                 if (ec.ConstantCheckState)
 720                                                         res = checked (((IntConstant) left).Value %
 721                                                                        ((IntConstant) right).Value);
 722                                                 else
 723                                                         res = unchecked (((IntConstant) left).Value %
 724                                                                          ((IntConstant) right).Value);
 725
 726                                                 return new IntConstant (res);
 727                                         } else {
 728                                                 throw new Exception ( "Unexepected input: " + left);
 729                                         }
 730                                 } catch (OverflowException){
 731                                         Error_CompileTimeOverflow (loc);
 732                                 }
 733                                 break;
 734
 735                                 //
 736                                 // There is no overflow checking on left shift
 737                                 //
 738                         case Binary.Operator.LeftShift:
 739                                 IntConstant ic = right.ToInt (loc);
 740                                 if (ic == null){
 741                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 742                                         return null;
 743                                 }
 744                                 int lshift_val = ic.Value;
 745
 746                                 IntConstant lic;
 747                                 if ((lic = left.ConvertToInt ()) != null)
 748                                         return new IntConstant (lic.Value << lshift_val);
 749
 750                                 UIntConstant luic;
 751                                 if ((luic = left.ConvertToUInt ()) != null)
 752                                         return new UIntConstant (luic.Value << lshift_val);
 753
 754                                 LongConstant llc;
 755                                 if ((llc = left.ConvertToLong ()) != null)
 756                                         return new LongConstant (llc.Value << lshift_val);
 757
 758                                 ULongConstant lulc;
 759                                 if ((lulc = left.ConvertToULong ()) != null)
 760                                         return new ULongConstant (lulc.Value << lshift_val);
 761
 762                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 763                                 break;
 764
 765                                 //
 766                                 // There is no overflow checking on right shift
 767                                 //
 768                         case Binary.Operator.RightShift:
 769                                 IntConstant sic = right.ToInt (loc);
 770                                 if (sic == null){
 771                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 772                                         return null;
 773                                 }
 774                                 int rshift_val = sic.Value;
 775
 776                                 IntConstant ric;
 777                                 if ((ric = left.ConvertToInt ()) != null)
 778                                         return new IntConstant (ric.Value >> rshift_val);
 779
 780                                 UIntConstant ruic;
 781                                 if ((ruic = left.ConvertToUInt ()) != null)
 782                                         return new UIntConstant (ruic.Value >> rshift_val);
 783
 784                                 LongConstant rlc;
 785                                 if ((rlc = left.ConvertToLong ()) != null)
 786                                         return new LongConstant (rlc.Value >> rshift_val);
 787
 788                                 ULongConstant rulc;
 789                                 if ((rulc = left.ConvertToULong ()) != null)
 790                                         return new ULongConstant (rulc.Value >> rshift_val);
 791
 792                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 793                                 break;
 794
 795                         case Binary.Operator.LogicalAnd:
 796                                 if (left is BoolConstant && right is BoolConstant){
 797                                         return new BoolConstant (
 798                                                 ((BoolConstant) left).Value &&
 799                                                 ((BoolConstant) right).Value);
 800                                 }
 801                                 break;
 802
 803                         case Binary.Operator.LogicalOr:
 804                                 if (left is BoolConstant && right is BoolConstant){
 805                                         return new BoolConstant (
 806                                                 ((BoolConstant) left).Value ||
 807                                                 ((BoolConstant) right).Value);
 808                                 }
 809                                 break;
 810
 811                         case Binary.Operator.Equality:
 812                                 if (left is BoolConstant && right is BoolConstant){
 813                                         return new BoolConstant (
 814                                                 ((BoolConstant) left).Value ==
 815                                                 ((BoolConstant) right).Value);
 816
 817                                 }
 818                                 if (left is StringConstant && right is StringConstant){
 819                                         return new BoolConstant (
 820                                                 ((StringConstant) left).Value ==
 821                                                 ((StringConstant) right).Value);
 822
 823                                 }
 824
 825                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 826                                 if (left == null || right == null)
 827                                         return null;
 828
 829                                 bool_res = false;
 830                                 if (left is DoubleConstant)
 831                                         bool_res = ((DoubleConstant) left).Value ==
 832                                                 ((DoubleConstant) right).Value;
 833                                 else if (left is FloatConstant)
 834                                         bool_res = ((FloatConstant) left).Value ==
 835                                                 ((FloatConstant) right).Value;
 836                                 else if (left is ULongConstant)
 837                                         bool_res = ((ULongConstant) left).Value ==
 838                                                 ((ULongConstant) right).Value;
 839                                 else if (left is LongConstant)
 840                                         bool_res = ((LongConstant) left).Value ==
 841                                                 ((LongConstant) right).Value;
 842                                 else if (left is UIntConstant)
 843                                         bool_res = ((UIntConstant) left).Value ==
 844                                                 ((UIntConstant) right).Value;
 845                                 else if (left is IntConstant)
 846                                         bool_res = ((IntConstant) left).Value ==
 847                                                 ((IntConstant) right).Value;
 848                                 else
 849                                         return null;
 850
 851                                 return new BoolConstant (bool_res);
 852
 853                         case Binary.Operator.Inequality:
 854                                 if (left is BoolConstant && right is BoolConstant){
 855                                         return new BoolConstant (
 856                                                 ((BoolConstant) left).Value !=
 857                                                 ((BoolConstant) right).Value);
 858                                 }
 859                                 if (left is StringConstant && right is StringConstant){
 860                                         return new BoolConstant (
 861                                                 ((StringConstant) left).Value !=
 862                                                 ((StringConstant) right).Value);
 863
 864                                 }
 865                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 866                                 if (left == null || right == null)
 867                                         return null;
 868
 869                                 bool_res = false;
 870                                 if (left is DoubleConstant)
 871                                         bool_res = ((DoubleConstant) left).Value !=
 872                                                 ((DoubleConstant) right).Value;
 873                                 else if (left is FloatConstant)
 874                                         bool_res = ((FloatConstant) left).Value !=
 875                                                 ((FloatConstant) right).Value;
 876                                 else if (left is ULongConstant)
 877                                         bool_res = ((ULongConstant) left).Value !=
 878                                                 ((ULongConstant) right).Value;
 879                                 else if (left is LongConstant)
 880                                         bool_res = ((LongConstant) left).Value !=
 881                                                 ((LongConstant) right).Value;
 882                                 else if (left is UIntConstant)
 883                                         bool_res = ((UIntConstant) left).Value !=
 884                                                 ((UIntConstant) right).Value;
 885                                 else if (left is IntConstant)
 886                                         bool_res = ((IntConstant) left).Value !=
 887                                                 ((IntConstant) right).Value;
 888                                 else
 889                                         return null;
 890
 891                                 return new BoolConstant (bool_res);
 892
 893                         case Binary.Operator.LessThan:
 894                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 895                                 if (left == null || right == null)
 896                                         return null;
 897
 898                                 bool_res = false;
 899                                 if (left is DoubleConstant)
 900                                         bool_res = ((DoubleConstant) left).Value <
 901                                                 ((DoubleConstant) right).Value;
 902                                 else if (left is FloatConstant)
 903                                         bool_res = ((FloatConstant) left).Value <
 904                                                 ((FloatConstant) right).Value;
 905                                 else if (left is ULongConstant)
 906                                         bool_res = ((ULongConstant) left).Value <
 907                                                 ((ULongConstant) right).Value;
 908                                 else if (left is LongConstant)
 909                                         bool_res = ((LongConstant) left).Value <
 910                                                 ((LongConstant) right).Value;
 911                                 else if (left is UIntConstant)
 912                                         bool_res = ((UIntConstant) left).Value <
 913                                                 ((UIntConstant) right).Value;
 914                                 else if (left is IntConstant)
 915                                         bool_res = ((IntConstant) left).Value <
 916                                                 ((IntConstant) right).Value;
 917                                 else
 918                                         return null;
 919
 920                                 return new BoolConstant (bool_res);
 921
 922                         case Binary.Operator.GreaterThan:
 923                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 924                                 if (left == null || right == null)
 925                                         return null;
 926
 927                                 bool_res = false;
 928                                 if (left is DoubleConstant)
 929                                         bool_res = ((DoubleConstant) left).Value >
 930                                                 ((DoubleConstant) right).Value;
 931                                 else if (left is FloatConstant)
 932                                         bool_res = ((FloatConstant) left).Value >
 933                                                 ((FloatConstant) right).Value;
 934                                 else if (left is ULongConstant)
 935                                         bool_res = ((ULongConstant) left).Value >
 936                                                 ((ULongConstant) right).Value;
 937                                 else if (left is LongConstant)
 938                                         bool_res = ((LongConstant) left).Value >
 939                                                 ((LongConstant) right).Value;
 940                                 else if (left is UIntConstant)
 941                                         bool_res = ((UIntConstant) left).Value >
 942                                                 ((UIntConstant) right).Value;
 943                                 else if (left is IntConstant)
 944                                         bool_res = ((IntConstant) left).Value >
 945                                                 ((IntConstant) right).Value;
 946                                 else
 947                                         return null;
 948
 949                                 return new BoolConstant (bool_res);
 950
 951                         case Binary.Operator.GreaterThanOrEqual:
 952                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 953                                 if (left == null || right == null)
 954                                         return null;
 955
 956                                 bool_res = false;
 957                                 if (left is DoubleConstant)
 958                                         bool_res = ((DoubleConstant) left).Value >=
 959                                                 ((DoubleConstant) right).Value;
 960                                 else if (left is FloatConstant)
 961                                         bool_res = ((FloatConstant) left).Value >=
 962                                                 ((FloatConstant) right).Value;
 963                                 else if (left is ULongConstant)
 964                                         bool_res = ((ULongConstant) left).Value >=
 965                                                 ((ULongConstant) right).Value;
 966                                 else if (left is LongConstant)
 967                                         bool_res = ((LongConstant) left).Value >=
 968                                                 ((LongConstant) right).Value;
 969                                 else if (left is UIntConstant)
 970                                         bool_res = ((UIntConstant) left).Value >=
 971                                                 ((UIntConstant) right).Value;
 972                                 else if (left is IntConstant)
 973                                         bool_res = ((IntConstant) left).Value >=
 974                                                 ((IntConstant) right).Value;
 975                                 else
 976                                         return null;
 977
 978                                 return new BoolConstant (bool_res);
 979
 980                         case Binary.Operator.LessThanOrEqual:
 981                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 982                                 if (left == null || right == null)
 983                                         return null;
 984
 985                                 bool_res = false;
 986                                 if (left is DoubleConstant)
 987                                         bool_res = ((DoubleConstant) left).Value <=
 988                                                 ((DoubleConstant) right).Value;
 989                                 else if (left is FloatConstant)
 990                                         bool_res = ((FloatConstant) left).Value <=
 991                                                 ((FloatConstant) right).Value;
 992                                 else if (left is ULongConstant)
 993                                         bool_res = ((ULongConstant) left).Value <=
 994                                                 ((ULongConstant) right).Value;
 995                                 else if (left is LongConstant)
 996                                         bool_res = ((LongConstant) left).Value <=
 997                                                 ((LongConstant) right).Value;
 998                                 else if (left is UIntConstant)
 999                                         bool_res = ((UIntConstant) left).Value <=
1000                                                 ((UIntConstant) right).Value;
1001                                 else if (left is IntConstant)
1002                                         bool_res = ((IntConstant) left).Value <=
1003                                                 ((IntConstant) right).Value;
1004                                 else
1005                                         return null;
1006
1007                                 return new BoolConstant (bool_res);
1008                         }
1009
1010                         return null;
1011                 }
1012         }
1013 }