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, the operands are
  97                                 // converted to type long.
  98                                 //
  99                                 Constant match, other;
 100                                 if (left is UIntConstant){
 101                                         other = right;
 102                                         match = left;
 103                                 } else {
 104                                         other = left;
 105                                         match = right;
 106                                 }
 107
 108                                 // Nothing to do.
 109                                 if (other is UIntConstant)
 110                                         return;
 111
 112                                 if (other is SByteConstant || other is ShortConstant ||
 113                                     other is IntConstant){
 114                                         left = left.ToLong (loc);
 115                                         right = right.ToLong (loc);
 116                                 }
 117
 118                                 return;
 119                         } else {
 120                                 //
 121                                 // Force conversions to int32
 122                                 //
 123                                 if (!(left is IntConstant))
 124                                         left = left.ToInt (loc);
 125                                 if (!(right is IntConstant))
 126                                         right = right.ToInt (loc);
 127                         }
 128                         return;
 129                 }
 130
 131                 static void Error_CompileTimeOverflow (Location loc)
 132                 {
 133                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 134                 }
 135
 136                 /// <summary>
 137                 ///   Constant expression folder for binary operations.
 138                 ///
 139                 ///   Returns null if the expression can not be folded.
 140                 /// </summary>
 141                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 142                                                      Constant left, Constant right, Location loc)
 143                 {
 144                         Type lt = left.Type;
 145                         Type rt = right.Type;
 146                         Type result_type = null;
 147                         bool bool_res;
 148
 149                         //
 150                         // Enumerator folding
 151                         //
 152                         if (rt == lt && left is EnumConstant)
 153                                 result_type = lt;
 154
 155                         //
 156                         // During an enum evaluation, we need to unwrap enumerations
 157                         //
 158                         if (ec.InEnumContext){
 159                                 if (left is EnumConstant)
 160                                         left = ((EnumConstant) left).Child;
 161
 162                                 if (right is EnumConstant)
 163                                         right = ((EnumConstant) right).Child;
 164                         }
 165
 166                         switch (oper){
 167                         case Binary.Operator.BitwiseOr:
 168                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 169                                 if (left == null || right == null)
 170                                         return null;
 171
 172                                 if (left is IntConstant){
 173                                         IntConstant v;
 174                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 175
 176                                         v = new IntConstant (res);
 177                                         if (result_type == null)
 178                                                 return v;
 179                                         else
 180                                                 return new EnumConstant (v, result_type);
 181                                 } else if (left is UIntConstant){
 182                                         UIntConstant v;
 183                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 184
 185                                         v = new UIntConstant (res);
 186                                         if (result_type == null)
 187                                                 return v;
 188                                         else
 189                                                 return new EnumConstant (v, result_type);
 190                                 } else if (left is LongConstant){
 191                                         LongConstant v;
 192                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 193
 194                                         v = new LongConstant (res);
 195                                         if (result_type == null)
 196                                                 return v;
 197                                         else
 198                                                 return new EnumConstant (v, result_type);
 199                                 } else if (left is ULongConstant){
 200                                         ULongConstant v;
 201                                         ulong res = ((ULongConstant)left).Value |
 202                                                 ((ULongConstant)right).Value;
 203
 204                                         v = new ULongConstant (res);
 205                                         if (result_type == null)
 206                                                 return v;
 207                                         else
 208                                                 return new EnumConstant (v, result_type);
 209                                 }
 210                                 break;
 211
 212                         case Binary.Operator.BitwiseAnd:
 213                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 214                                 if (left == null || right == null)
 215                                         return null;
 216
 217                                 if (left is IntConstant){
 218                                         IntConstant v;
 219                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 220
 221                                         v = new IntConstant (res);
 222                                         if (result_type == null)
 223                                                 return v;
 224                                         else
 225                                                 return new EnumConstant (v, result_type);
 226                                 } else if (left is UIntConstant){
 227                                         UIntConstant v;
 228                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 229
 230                                         v = new UIntConstant (res);
 231                                         if (result_type == null)
 232                                                 return v;
 233                                         else
 234                                                 return new EnumConstant (v, result_type);
 235                                 } else if (left is LongConstant){
 236                                         LongConstant v;
 237                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 238
 239                                         v = new LongConstant (res);
 240                                         if (result_type == null)
 241                                                 return v;
 242                                         else
 243                                                 return new EnumConstant (v, result_type);
 244                                 } else if (left is ULongConstant){
 245                                         ULongConstant v;
 246                                         ulong res = ((ULongConstant)left).Value &
 247                                                 ((ULongConstant)right).Value;
 248
 249                                         v = new ULongConstant (res);
 250                                         if (result_type == null)
 251                                                 return v;
 252                                         else
 253                                                 return new EnumConstant (v, result_type);
 254                                 }
 255                                 break;
 256
 257                         case Binary.Operator.ExclusiveOr:
 258                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 259                                 if (left == null || right == null)
 260                                         return null;
 261
 262                                 if (left is IntConstant){
 263                                         IntConstant v;
 264                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 265
 266                                         v = new IntConstant (res);
 267                                         if (result_type == null)
 268                                                 return v;
 269                                         else
 270                                                 return new EnumConstant (v, result_type);
 271                                 } else if (left is UIntConstant){
 272                                         UIntConstant v;
 273                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 274
 275                                         v = new UIntConstant (res);
 276                                         if (result_type == null)
 277                                                 return v;
 278                                         else
 279                                                 return new EnumConstant (v, result_type);
 280                                 } else if (left is LongConstant){
 281                                         LongConstant v;
 282                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 283
 284                                         v = new LongConstant (res);
 285                                         if (result_type == null)
 286                                                 return v;
 287                                         else
 288                                                 return new EnumConstant (v, result_type);
 289                                 } else if (left is ULongConstant){
 290                                         ULongConstant v;
 291                                         ulong res = ((ULongConstant)left).Value ^
 292                                                 ((ULongConstant)right).Value;
 293
 294                                         v = new ULongConstant (res);
 295                                         if (result_type == null)
 296                                                 return v;
 297                                         else
 298                                                 return new EnumConstant (v, result_type);
 299                                 }
 300                                 break;
 301
 302                         case Binary.Operator.Addition:
 303                                 Constant result;
 304                                 bool left_is_string = left is StringConstant;
 305                                 bool right_is_string = right is StringConstant;
 306
 307                                 //
 308                                 // If both sides are strings, then concatenate, if
 309                                 // one is a string, and the other is not, then defer
 310                                 // to runtime concatenation
 311                                 //
 312                                 if (left_is_string || right_is_string){
 313                                         if (left_is_string && right_is_string)
 314                                                 return new StringConstant (
 315                                                         ((StringConstant) left).Value +
 316                                                         ((StringConstant) right).Value);
 317
 318                                         return null;
 319                                 }
 320
 321                                 //
 322                                 // handle "E operator + (E x, U y)"
 323                                 // handle "E operator + (Y y, E x)"
 324                                 //
 325                                 // note that E operator + (E x, E y) is invalid
 326                                 //
 327                                 Type wrap_as = null;
 328                                 if (left is EnumConstant){
 329                                         if (right is EnumConstant){
 330                                                 return null;
 331                                         }
 332                                         if (((EnumConstant) left).Child.Type != right.Type)
 333                                                 return null;
 334
 335                                         wrap_as = left.Type;
 336                                 } else if (right is EnumConstant){
 337                                         if (((EnumConstant) right).Child.Type != left.Type)
 338                                                 return null;
 339                                         wrap_as = right.Type;
 340                                 }
 341
 342                                 result = null;
 343                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 344                                 if (left == null || right == null)
 345                                         return null;
 346
 347                                 try {
 348                                         if (left is DoubleConstant){
 349                                                 double res;
 350
 351                                                 if (ec.ConstantCheckState)
 352                                                         res = checked (((DoubleConstant) left).Value +
 353                                                                        ((DoubleConstant) right).Value);
 354                                                 else
 355                                                         res = unchecked (((DoubleConstant) left).Value +
 356                                                                          ((DoubleConstant) right).Value);
 357
 358                                                 result = new DoubleConstant (res);
 359                                         } else if (left is FloatConstant){
 360                                                 float res;
 361
 362                                                 if (ec.ConstantCheckState)
 363                                                         res = checked (((FloatConstant) left).Value +
 364                                                                        ((FloatConstant) right).Value);
 365                                                 else
 366                                                         res = unchecked (((FloatConstant) left).Value +
 367                                                                          ((FloatConstant) right).Value);
 368
 369                                                 result = new FloatConstant (res);
 370                                         } else if (left is ULongConstant){
 371                                                 ulong res;
 372
 373                                                 if (ec.ConstantCheckState)
 374                                                         res = checked (((ULongConstant) left).Value +
 375                                                                        ((ULongConstant) right).Value);
 376                                                 else
 377                                                         res = unchecked (((ULongConstant) left).Value +
 378                                                                          ((ULongConstant) right).Value);
 379
 380                                                 result = new ULongConstant (res);
 381                                         } else if (left is LongConstant){
 382                                                 long res;
 383
 384                                                 if (ec.ConstantCheckState)
 385                                                         res = checked (((LongConstant) left).Value +
 386                                                                        ((LongConstant) right).Value);
 387                                                 else
 388                                                         res = unchecked (((LongConstant) left).Value +
 389                                                                          ((LongConstant) right).Value);
 390
 391                                                 result = new LongConstant (res);
 392                                         } else if (left is UIntConstant){
 393                                                 uint res;
 394
 395                                                 if (ec.ConstantCheckState)
 396                                                         res = checked (((UIntConstant) left).Value +
 397                                                                        ((UIntConstant) right).Value);
 398                                                 else
 399                                                         res = unchecked (((UIntConstant) left).Value +
 400                                                                          ((UIntConstant) right).Value);
 401
 402                                                 result = new UIntConstant (res);
 403                                         } else if (left is IntConstant){
 404                                                 int res;
 405
 406                                                 if (ec.ConstantCheckState)
 407                                                         res = checked (((IntConstant) left).Value +
 408                                                                        ((IntConstant) right).Value);
 409                                                 else
 410                                                         res = unchecked (((IntConstant) left).Value +
 411                                                                          ((IntConstant) right).Value);
 412
 413                                                 result = new IntConstant (res);
 414                                         } else {
 415                                                 throw new Exception ( "Unexepected input: " + left);
 416                                         }
 417                                 } catch (OverflowException){
 418                                         Error_CompileTimeOverflow (loc);
 419                                 }
 420
 421                                 if (wrap_as != null)
 422                                         return new EnumConstant (result, wrap_as);
 423                                 else
 424                                         return result;
 425
 426                         case Binary.Operator.Subtraction:
 427                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 428                                 if (left == null || right == null)
 429                                         return null;
 430
 431                                 try {
 432                                         if (left is DoubleConstant){
 433                                                 double res;
 434
 435                                                 if (ec.ConstantCheckState)
 436                                                         res = checked (((DoubleConstant) left).Value -
 437                                                                        ((DoubleConstant) right).Value);
 438                                                 else
 439                                                         res = unchecked (((DoubleConstant) left).Value -
 440                                                                          ((DoubleConstant) right).Value);
 441
 442                                                 return new DoubleConstant (res);
 443                                         } else if (left is FloatConstant){
 444                                                 float res;
 445
 446                                                 if (ec.ConstantCheckState)
 447                                                         res = checked (((FloatConstant) left).Value -
 448                                                                        ((FloatConstant) right).Value);
 449                                                 else
 450                                                         res = unchecked (((FloatConstant) left).Value -
 451                                                                          ((FloatConstant) right).Value);
 452
 453                                                 return new FloatConstant (res);
 454                                         } else if (left is ULongConstant){
 455                                                 ulong res;
 456
 457                                                 if (ec.ConstantCheckState)
 458                                                         res = checked (((ULongConstant) left).Value -
 459                                                                        ((ULongConstant) right).Value);
 460                                                 else
 461                                                         res = unchecked (((ULongConstant) left).Value -
 462                                                                          ((ULongConstant) right).Value);
 463
 464                                                 return new ULongConstant (res);
 465                                         } else if (left is LongConstant){
 466                                                 long res;
 467
 468                                                 if (ec.ConstantCheckState)
 469                                                         res = checked (((LongConstant) left).Value -
 470                                                                        ((LongConstant) right).Value);
 471                                                 else
 472                                                         res = unchecked (((LongConstant) left).Value -
 473                                                                          ((LongConstant) right).Value);
 474
 475                                                 return new LongConstant (res);
 476                                         } else if (left is UIntConstant){
 477                                                 uint res;
 478
 479                                                 if (ec.ConstantCheckState)
 480                                                         res = checked (((UIntConstant) left).Value -
 481                                                                        ((UIntConstant) right).Value);
 482                                                 else
 483                                                         res = unchecked (((UIntConstant) left).Value -
 484                                                                          ((UIntConstant) right).Value);
 485
 486                                                 return new UIntConstant (res);
 487                                         } else if (left is IntConstant){
 488                                                 int res;
 489
 490                                                 if (ec.ConstantCheckState)
 491                                                         res = checked (((IntConstant) left).Value -
 492                                                                        ((IntConstant) right).Value);
 493                                                 else
 494                                                         res = unchecked (((IntConstant) left).Value -
 495                                                                          ((IntConstant) right).Value);
 496
 497                                                 return new IntConstant (res);
 498                                         } else {
 499                                                 throw new Exception ( "Unexepected input: " + left);
 500                                         }
 501                                 } catch (OverflowException){
 502                                         Error_CompileTimeOverflow (loc);
 503                                 }
 504                                 break;
 505
 506                         case Binary.Operator.Multiply:
 507                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 508                                 if (left == null || right == null)
 509                                         return null;
 510
 511                                 try {
 512                                         if (left is DoubleConstant){
 513                                                 double res;
 514
 515                                                 if (ec.ConstantCheckState)
 516                                                         res = checked (((DoubleConstant) left).Value *
 517                                                                        ((DoubleConstant) right).Value);
 518                                                 else
 519                                                         res = unchecked (((DoubleConstant) left).Value *
 520                                                                          ((DoubleConstant) right).Value);
 521
 522                                                 return new DoubleConstant (res);
 523                                         } else if (left is FloatConstant){
 524                                                 float res;
 525
 526                                                 if (ec.ConstantCheckState)
 527                                                         res = checked (((FloatConstant) left).Value *
 528                                                                        ((FloatConstant) right).Value);
 529                                                 else
 530                                                         res = unchecked (((FloatConstant) left).Value *
 531                                                                          ((FloatConstant) right).Value);
 532
 533                                                 return new FloatConstant (res);
 534                                         } else if (left is ULongConstant){
 535                                                 ulong res;
 536
 537                                                 if (ec.ConstantCheckState)
 538                                                         res = checked (((ULongConstant) left).Value *
 539                                                                        ((ULongConstant) right).Value);
 540                                                 else
 541                                                         res = unchecked (((ULongConstant) left).Value *
 542                                                                          ((ULongConstant) right).Value);
 543
 544                                                 return new ULongConstant (res);
 545                                         } else if (left is LongConstant){
 546                                                 long res;
 547
 548                                                 if (ec.ConstantCheckState)
 549                                                         res = checked (((LongConstant) left).Value *
 550                                                                        ((LongConstant) right).Value);
 551                                                 else
 552                                                         res = unchecked (((LongConstant) left).Value *
 553                                                                          ((LongConstant) right).Value);
 554
 555                                                 return new LongConstant (res);
 556                                         } else if (left is UIntConstant){
 557                                                 uint res;
 558
 559                                                 if (ec.ConstantCheckState)
 560                                                         res = checked (((UIntConstant) left).Value *
 561                                                                        ((UIntConstant) right).Value);
 562                                                 else
 563                                                         res = unchecked (((UIntConstant) left).Value *
 564                                                                          ((UIntConstant) right).Value);
 565
 566                                                 return new UIntConstant (res);
 567                                         } else if (left is IntConstant){
 568                                                 int res;
 569
 570                                                 if (ec.ConstantCheckState)
 571                                                         res = checked (((IntConstant) left).Value *
 572                                                                        ((IntConstant) right).Value);
 573                                                 else
 574                                                         res = unchecked (((IntConstant) left).Value *
 575                                                                          ((IntConstant) right).Value);
 576
 577                                                 return new IntConstant (res);
 578                                         } else {
 579                                                 throw new Exception ( "Unexepected input: " + left);
 580                                         }
 581                                 } catch (OverflowException){
 582                                         Error_CompileTimeOverflow (loc);
 583                                 }
 584                                 break;
 585
 586                         case Binary.Operator.Division:
 587                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 588                                 if (left == null || right == null)
 589                                         return null;
 590
 591                                 try {
 592                                         if (left is DoubleConstant){
 593                                                 double res;
 594
 595                                                 if (ec.ConstantCheckState)
 596                                                         res = checked (((DoubleConstant) left).Value /
 597                                                                        ((DoubleConstant) right).Value);
 598                                                 else
 599                                                         res = unchecked (((DoubleConstant) left).Value /
 600                                                                          ((DoubleConstant) right).Value);
 601
 602                                                 return new DoubleConstant (res);
 603                                         } else if (left is FloatConstant){
 604                                                 float res;
 605
 606                                                 if (ec.ConstantCheckState)
 607                                                         res = checked (((FloatConstant) left).Value /
 608                                                                        ((FloatConstant) right).Value);
 609                                                 else
 610                                                         res = unchecked (((FloatConstant) left).Value /
 611                                                                          ((FloatConstant) right).Value);
 612
 613                                                 return new FloatConstant (res);
 614                                         } else if (left is ULongConstant){
 615                                                 ulong res;
 616
 617                                                 if (ec.ConstantCheckState)
 618                                                         res = checked (((ULongConstant) left).Value /
 619                                                                        ((ULongConstant) right).Value);
 620                                                 else
 621                                                         res = unchecked (((ULongConstant) left).Value /
 622                                                                          ((ULongConstant) right).Value);
 623
 624                                                 return new ULongConstant (res);
 625                                         } else if (left is LongConstant){
 626                                                 long res;
 627
 628                                                 if (ec.ConstantCheckState)
 629                                                         res = checked (((LongConstant) left).Value /
 630                                                                        ((LongConstant) right).Value);
 631                                                 else
 632                                                         res = unchecked (((LongConstant) left).Value /
 633                                                                          ((LongConstant) right).Value);
 634
 635                                                 return new LongConstant (res);
 636                                         } else if (left is UIntConstant){
 637                                                 uint res;
 638
 639                                                 if (ec.ConstantCheckState)
 640                                                         res = checked (((UIntConstant) left).Value /
 641                                                                        ((UIntConstant) right).Value);
 642                                                 else
 643                                                         res = unchecked (((UIntConstant) left).Value /
 644                                                                          ((UIntConstant) right).Value);
 645
 646                                                 return new UIntConstant (res);
 647                                         } else if (left is IntConstant){
 648                                                 int res;
 649
 650                                                 if (ec.ConstantCheckState)
 651                                                         res = checked (((IntConstant) left).Value /
 652                                                                        ((IntConstant) right).Value);
 653                                                 else
 654                                                         res = unchecked (((IntConstant) left).Value /
 655                                                                          ((IntConstant) right).Value);
 656
 657                                                 return new IntConstant (res);
 658                                         } else {
 659                                                 throw new Exception ( "Unexepected input: " + left);
 660                                         }
 661                                 } catch (OverflowException){
 662                                         Error_CompileTimeOverflow (loc);
 663
 664                                 } catch (DivideByZeroException) {
 665                                         Report.Error (020, loc, "Division by constant zero");
 666                                 }
 667
 668                                 break;
 669
 670                         case Binary.Operator.Modulus:
 671                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 672                                 if (left == null || right == null)
 673                                         return null;
 674
 675                                 try {
 676                                         if (left is DoubleConstant){
 677                                                 double res;
 678
 679                                                 if (ec.ConstantCheckState)
 680                                                         res = checked (((DoubleConstant) left).Value %
 681                                                                        ((DoubleConstant) right).Value);
 682                                                 else
 683                                                         res = unchecked (((DoubleConstant) left).Value %
 684                                                                          ((DoubleConstant) right).Value);
 685
 686                                                 return new DoubleConstant (res);
 687                                         } else if (left is FloatConstant){
 688                                                 float res;
 689
 690                                                 if (ec.ConstantCheckState)
 691                                                         res = checked (((FloatConstant) left).Value %
 692                                                                        ((FloatConstant) right).Value);
 693                                                 else
 694                                                         res = unchecked (((FloatConstant) left).Value %
 695                                                                          ((FloatConstant) right).Value);
 696
 697                                                 return new FloatConstant (res);
 698                                         } else if (left is ULongConstant){
 699                                                 ulong res;
 700
 701                                                 if (ec.ConstantCheckState)
 702                                                         res = checked (((ULongConstant) left).Value %
 703                                                                        ((ULongConstant) right).Value);
 704                                                 else
 705                                                         res = unchecked (((ULongConstant) left).Value %
 706                                                                          ((ULongConstant) right).Value);
 707
 708                                                 return new ULongConstant (res);
 709                                         } else if (left is LongConstant){
 710                                                 long res;
 711
 712                                                 if (ec.ConstantCheckState)
 713                                                         res = checked (((LongConstant) left).Value %
 714                                                                        ((LongConstant) right).Value);
 715                                                 else
 716                                                         res = unchecked (((LongConstant) left).Value %
 717                                                                          ((LongConstant) right).Value);
 718
 719                                                 return new LongConstant (res);
 720                                         } else if (left is UIntConstant){
 721                                                 uint res;
 722
 723                                                 if (ec.ConstantCheckState)
 724                                                         res = checked (((UIntConstant) left).Value %
 725                                                                        ((UIntConstant) right).Value);
 726                                                 else
 727                                                         res = unchecked (((UIntConstant) left).Value %
 728                                                                          ((UIntConstant) right).Value);
 729
 730                                                 return new UIntConstant (res);
 731                                         } else if (left is IntConstant){
 732                                                 int res;
 733
 734                                                 if (ec.ConstantCheckState)
 735                                                         res = checked (((IntConstant) left).Value %
 736                                                                        ((IntConstant) right).Value);
 737                                                 else
 738                                                         res = unchecked (((IntConstant) left).Value %
 739                                                                          ((IntConstant) right).Value);
 740
 741                                                 return new IntConstant (res);
 742                                         } else {
 743                                                 throw new Exception ( "Unexepected input: " + left);
 744                                         }
 745                                 } catch (OverflowException){
 746                                         Error_CompileTimeOverflow (loc);
 747                                 }
 748                                 break;
 749
 750                                 //
 751                                 // There is no overflow checking on left shift
 752                                 //
 753                         case Binary.Operator.LeftShift:
 754                                 IntConstant ic = right.ToInt (loc);
 755                                 if (ic == null){
 756                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 757                                         return null;
 758                                 }
 759                                 int lshift_val = ic.Value;
 760
 761                                 IntConstant lic;
 762                                 if ((lic = left.ConvertToInt ()) != null)
 763                                         return new IntConstant (lic.Value << lshift_val);
 764
 765                                 UIntConstant luic;
 766                                 if ((luic = left.ConvertToUInt ()) != null)
 767                                         return new UIntConstant (luic.Value << lshift_val);
 768
 769                                 LongConstant llc;
 770                                 if ((llc = left.ConvertToLong ()) != null)
 771                                         return new LongConstant (llc.Value << lshift_val);
 772
 773                                 ULongConstant lulc;
 774                                 if ((lulc = left.ConvertToULong ()) != null)
 775                                         return new ULongConstant (lulc.Value << lshift_val);
 776
 777                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 778                                 break;
 779
 780                                 //
 781                                 // There is no overflow checking on right shift
 782                                 //
 783                         case Binary.Operator.RightShift:
 784                                 IntConstant sic = right.ToInt (loc);
 785                                 if (sic == null){
 786                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 787                                         return null;
 788                                 }
 789                                 int rshift_val = sic.Value;
 790
 791                                 IntConstant ric;
 792                                 if ((ric = left.ConvertToInt ()) != null)
 793                                         return new IntConstant (ric.Value >> rshift_val);
 794
 795                                 UIntConstant ruic;
 796                                 if ((ruic = left.ConvertToUInt ()) != null)
 797                                         return new UIntConstant (ruic.Value >> rshift_val);
 798
 799                                 LongConstant rlc;
 800                                 if ((rlc = left.ConvertToLong ()) != null)
 801                                         return new LongConstant (rlc.Value >> rshift_val);
 802
 803                                 ULongConstant rulc;
 804                                 if ((rulc = left.ConvertToULong ()) != null)
 805                                         return new ULongConstant (rulc.Value >> rshift_val);
 806
 807                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 808                                 break;
 809
 810                         case Binary.Operator.LogicalAnd:
 811                                 if (left is BoolConstant && right is BoolConstant){
 812                                         return new BoolConstant (
 813                                                 ((BoolConstant) left).Value &&
 814                                                 ((BoolConstant) right).Value);
 815                                 }
 816                                 break;
 817
 818                         case Binary.Operator.LogicalOr:
 819                                 if (left is BoolConstant && right is BoolConstant){
 820                                         return new BoolConstant (
 821                                                 ((BoolConstant) left).Value ||
 822                                                 ((BoolConstant) right).Value);
 823                                 }
 824                                 break;
 825
 826                         case Binary.Operator.Equality:
 827                                 if (left is BoolConstant && right is BoolConstant){
 828                                         return new BoolConstant (
 829                                                 ((BoolConstant) left).Value ==
 830                                                 ((BoolConstant) right).Value);
 831
 832                                 }
 833                                 if (left is StringConstant && right is StringConstant){
 834                                         return new BoolConstant (
 835                                                 ((StringConstant) left).Value ==
 836                                                 ((StringConstant) right).Value);
 837
 838                                 }
 839
 840                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 841                                 if (left == null || right == null)
 842                                         return null;
 843
 844                                 bool_res = false;
 845                                 if (left is DoubleConstant)
 846                                         bool_res = ((DoubleConstant) left).Value ==
 847                                                 ((DoubleConstant) right).Value;
 848                                 else if (left is FloatConstant)
 849                                         bool_res = ((FloatConstant) left).Value ==
 850                                                 ((FloatConstant) right).Value;
 851                                 else if (left is ULongConstant)
 852                                         bool_res = ((ULongConstant) left).Value ==
 853                                                 ((ULongConstant) right).Value;
 854                                 else if (left is LongConstant)
 855                                         bool_res = ((LongConstant) left).Value ==
 856                                                 ((LongConstant) right).Value;
 857                                 else if (left is UIntConstant)
 858                                         bool_res = ((UIntConstant) left).Value ==
 859                                                 ((UIntConstant) right).Value;
 860                                 else if (left is IntConstant)
 861                                         bool_res = ((IntConstant) left).Value ==
 862                                                 ((IntConstant) right).Value;
 863                                 else
 864                                         return null;
 865
 866                                 return new BoolConstant (bool_res);
 867
 868                         case Binary.Operator.Inequality:
 869                                 if (left is BoolConstant && right is BoolConstant){
 870                                         return new BoolConstant (
 871                                                 ((BoolConstant) left).Value !=
 872                                                 ((BoolConstant) right).Value);
 873                                 }
 874                                 if (left is StringConstant && right is StringConstant){
 875                                         return new BoolConstant (
 876                                                 ((StringConstant) left).Value !=
 877                                                 ((StringConstant) right).Value);
 878
 879                                 }
 880                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 881                                 if (left == null || right == null)
 882                                         return null;
 883
 884                                 bool_res = false;
 885                                 if (left is DoubleConstant)
 886                                         bool_res = ((DoubleConstant) left).Value !=
 887                                                 ((DoubleConstant) right).Value;
 888                                 else if (left is FloatConstant)
 889                                         bool_res = ((FloatConstant) left).Value !=
 890                                                 ((FloatConstant) right).Value;
 891                                 else if (left is ULongConstant)
 892                                         bool_res = ((ULongConstant) left).Value !=
 893                                                 ((ULongConstant) right).Value;
 894                                 else if (left is LongConstant)
 895                                         bool_res = ((LongConstant) left).Value !=
 896                                                 ((LongConstant) right).Value;
 897                                 else if (left is UIntConstant)
 898                                         bool_res = ((UIntConstant) left).Value !=
 899                                                 ((UIntConstant) right).Value;
 900                                 else if (left is IntConstant)
 901                                         bool_res = ((IntConstant) left).Value !=
 902                                                 ((IntConstant) right).Value;
 903                                 else
 904                                         return null;
 905
 906                                 return new BoolConstant (bool_res);
 907
 908                         case Binary.Operator.LessThan:
 909                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 910                                 if (left == null || right == null)
 911                                         return null;
 912
 913                                 bool_res = false;
 914                                 if (left is DoubleConstant)
 915                                         bool_res = ((DoubleConstant) left).Value <
 916                                                 ((DoubleConstant) right).Value;
 917                                 else if (left is FloatConstant)
 918                                         bool_res = ((FloatConstant) left).Value <
 919                                                 ((FloatConstant) right).Value;
 920                                 else if (left is ULongConstant)
 921                                         bool_res = ((ULongConstant) left).Value <
 922                                                 ((ULongConstant) right).Value;
 923                                 else if (left is LongConstant)
 924                                         bool_res = ((LongConstant) left).Value <
 925                                                 ((LongConstant) right).Value;
 926                                 else if (left is UIntConstant)
 927                                         bool_res = ((UIntConstant) left).Value <
 928                                                 ((UIntConstant) right).Value;
 929                                 else if (left is IntConstant)
 930                                         bool_res = ((IntConstant) left).Value <
 931                                                 ((IntConstant) right).Value;
 932                                 else
 933                                         return null;
 934
 935                                 return new BoolConstant (bool_res);
 936
 937                         case Binary.Operator.GreaterThan:
 938                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 939                                 if (left == null || right == null)
 940                                         return null;
 941
 942                                 bool_res = false;
 943                                 if (left is DoubleConstant)
 944                                         bool_res = ((DoubleConstant) left).Value >
 945                                                 ((DoubleConstant) right).Value;
 946                                 else if (left is FloatConstant)
 947                                         bool_res = ((FloatConstant) left).Value >
 948                                                 ((FloatConstant) right).Value;
 949                                 else if (left is ULongConstant)
 950                                         bool_res = ((ULongConstant) left).Value >
 951                                                 ((ULongConstant) right).Value;
 952                                 else if (left is LongConstant)
 953                                         bool_res = ((LongConstant) left).Value >
 954                                                 ((LongConstant) right).Value;
 955                                 else if (left is UIntConstant)
 956                                         bool_res = ((UIntConstant) left).Value >
 957                                                 ((UIntConstant) right).Value;
 958                                 else if (left is IntConstant)
 959                                         bool_res = ((IntConstant) left).Value >
 960                                                 ((IntConstant) right).Value;
 961                                 else
 962                                         return null;
 963
 964                                 return new BoolConstant (bool_res);
 965
 966                         case Binary.Operator.GreaterThanOrEqual:
 967                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 968                                 if (left == null || right == null)
 969                                         return null;
 970
 971                                 bool_res = false;
 972                                 if (left is DoubleConstant)
 973                                         bool_res = ((DoubleConstant) left).Value >=
 974                                                 ((DoubleConstant) right).Value;
 975                                 else if (left is FloatConstant)
 976                                         bool_res = ((FloatConstant) left).Value >=
 977                                                 ((FloatConstant) right).Value;
 978                                 else if (left is ULongConstant)
 979                                         bool_res = ((ULongConstant) left).Value >=
 980                                                 ((ULongConstant) right).Value;
 981                                 else if (left is LongConstant)
 982                                         bool_res = ((LongConstant) left).Value >=
 983                                                 ((LongConstant) right).Value;
 984                                 else if (left is UIntConstant)
 985                                         bool_res = ((UIntConstant) left).Value >=
 986                                                 ((UIntConstant) right).Value;
 987                                 else if (left is IntConstant)
 988                                         bool_res = ((IntConstant) left).Value >=
 989                                                 ((IntConstant) right).Value;
 990                                 else
 991                                         return null;
 992
 993                                 return new BoolConstant (bool_res);
 994
 995                         case Binary.Operator.LessThanOrEqual:
 996                                 DoConstantNumericPromotions (oper, ref left, ref right, loc);
 997                                 if (left == null || right == null)
 998                                         return null;
 999
1000                                 bool_res = false;
1001                                 if (left is DoubleConstant)
1002                                         bool_res = ((DoubleConstant) left).Value <=
1003                                                 ((DoubleConstant) right).Value;
1004                                 else if (left is FloatConstant)
1005                                         bool_res = ((FloatConstant) left).Value <=
1006                                                 ((FloatConstant) right).Value;
1007                                 else if (left is ULongConstant)
1008                                         bool_res = ((ULongConstant) left).Value <=
1009                                                 ((ULongConstant) right).Value;
1010                                 else if (left is LongConstant)
1011                                         bool_res = ((LongConstant) left).Value <=
1012                                                 ((LongConstant) right).Value;
1013                                 else if (left is UIntConstant)
1014                                         bool_res = ((UIntConstant) left).Value <=
1015                                                 ((UIntConstant) right).Value;
1016                                 else if (left is IntConstant)
1017                                         bool_res = ((IntConstant) left).Value <=
1018                                                 ((IntConstant) right).Value;
1019                                 else
1020                                         return null;
1021
1022                                 return new BoolConstant (bool_res);
1023                         }
1024
1025                         return null;
1026                 }
1027         }
1028 }