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 (EmitContext ec, 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 if (left is EnumConstant || right is EnumConstant){
 120                                 //
 121                                 // If either operand is an enum constant, the other one must
 122                                 // be implicitly convertable to that enum's underlying type.
 123                                 //
 124                                 EnumConstant match;
 125                                 Constant other;
 126                                 if (left is EnumConstant){
 127                                         other = right;
 128                                         match = (EnumConstant) left;
 129                                 } else {
 130                                         other = left;
 131                                         match = (EnumConstant) right;
 132                                 }
 133
 134                                 bool need_check = (other is EnumConstant) ||
 135                                         ((oper != Binary.Operator.Addition) &&
 136                                          (oper != Binary.Operator.Subtraction));
 137
 138                                 if (need_check &&
 139                                     !Expression.ImplicitConversionExists (ec, match, other.Type)) {
 140                                         Expression.Error_CannotConvertImplicit (loc, match.Type, other.Type);
 141                                         left = null;
 142                                         right = null;
 143                                         return;
 144                                 }
 145
 146                                 if (left is EnumConstant)
 147                                         left = ((EnumConstant) left).Child;
 148                                 if (right is EnumConstant)
 149                                         right = ((EnumConstant) right).Child;
 150                                 return;
 151
 152                         } else {
 153                                 //
 154                                 // Force conversions to int32
 155                                 //
 156                                 if (!(left is IntConstant))
 157                                         left = left.ToInt (loc);
 158                                 if (!(right is IntConstant))
 159                                         right = right.ToInt (loc);
 160                         }
 161                         return;
 162                 }
 163
 164                 static void Error_CompileTimeOverflow (Location loc)
 165                 {
 166                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 167                 }
 168
 169                 /// <summary>
 170                 ///   Constant expression folder for binary operations.
 171                 ///
 172                 ///   Returns null if the expression can not be folded.
 173                 /// </summary>
 174                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 175                                                      Constant left, Constant right, Location loc)
 176                 {
 177                         Type lt = left.Type;
 178                         Type rt = right.Type;
 179                         Type result_type = null;
 180                         bool bool_res;
 181
 182                         //
 183                         // Enumerator folding
 184                         //
 185                         if (rt == lt && left is EnumConstant)
 186                                 result_type = lt;
 187
 188                         //
 189                         // During an enum evaluation, we need to unwrap enumerations
 190                         //
 191                         if (ec.InEnumContext){
 192                                 if (left is EnumConstant)
 193                                         left = ((EnumConstant) left).Child;
 194
 195                                 if (right is EnumConstant)
 196                                         right = ((EnumConstant) right).Child;
 197                         }
 198
 199                         switch (oper){
 200                         case Binary.Operator.BitwiseOr:
 201                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 202                                 if (left == null || right == null)
 203                                         return null;
 204
 205                                 if (left is IntConstant){
 206                                         IntConstant v;
 207                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 208
 209                                         v = new IntConstant (res);
 210                                         if (result_type == null)
 211                                                 return v;
 212                                         else
 213                                                 return new EnumConstant (v, result_type);
 214                                 } else if (left is UIntConstant){
 215                                         UIntConstant v;
 216                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 217
 218                                         v = new UIntConstant (res);
 219                                         if (result_type == null)
 220                                                 return v;
 221                                         else
 222                                                 return new EnumConstant (v, result_type);
 223                                 } else if (left is LongConstant){
 224                                         LongConstant v;
 225                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 226
 227                                         v = new LongConstant (res);
 228                                         if (result_type == null)
 229                                                 return v;
 230                                         else
 231                                                 return new EnumConstant (v, result_type);
 232                                 } else if (left is ULongConstant){
 233                                         ULongConstant v;
 234                                         ulong res = ((ULongConstant)left).Value |
 235                                                 ((ULongConstant)right).Value;
 236
 237                                         v = new ULongConstant (res);
 238                                         if (result_type == null)
 239                                                 return v;
 240                                         else
 241                                                 return new EnumConstant (v, result_type);
 242                                 }
 243                                 break;
 244
 245                         case Binary.Operator.BitwiseAnd:
 246                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 247                                 if (left == null || right == null)
 248                                         return null;
 249
 250                                 if (left is IntConstant){
 251                                         IntConstant v;
 252                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 253
 254                                         v = new IntConstant (res);
 255                                         if (result_type == null)
 256                                                 return v;
 257                                         else
 258                                                 return new EnumConstant (v, result_type);
 259                                 } else if (left is UIntConstant){
 260                                         UIntConstant v;
 261                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 262
 263                                         v = new UIntConstant (res);
 264                                         if (result_type == null)
 265                                                 return v;
 266                                         else
 267                                                 return new EnumConstant (v, result_type);
 268                                 } else if (left is LongConstant){
 269                                         LongConstant v;
 270                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 271
 272                                         v = new LongConstant (res);
 273                                         if (result_type == null)
 274                                                 return v;
 275                                         else
 276                                                 return new EnumConstant (v, result_type);
 277                                 } else if (left is ULongConstant){
 278                                         ULongConstant v;
 279                                         ulong res = ((ULongConstant)left).Value &
 280                                                 ((ULongConstant)right).Value;
 281
 282                                         v = new ULongConstant (res);
 283                                         if (result_type == null)
 284                                                 return v;
 285                                         else
 286                                                 return new EnumConstant (v, result_type);
 287                                 }
 288                                 break;
 289
 290                         case Binary.Operator.ExclusiveOr:
 291                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 292                                 if (left == null || right == null)
 293                                         return null;
 294
 295                                 if (left is IntConstant){
 296                                         IntConstant v;
 297                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 298
 299                                         v = new IntConstant (res);
 300                                         if (result_type == null)
 301                                                 return v;
 302                                         else
 303                                                 return new EnumConstant (v, result_type);
 304                                 } else if (left is UIntConstant){
 305                                         UIntConstant v;
 306                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 307
 308                                         v = new UIntConstant (res);
 309                                         if (result_type == null)
 310                                                 return v;
 311                                         else
 312                                                 return new EnumConstant (v, result_type);
 313                                 } else if (left is LongConstant){
 314                                         LongConstant v;
 315                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 316
 317                                         v = new LongConstant (res);
 318                                         if (result_type == null)
 319                                                 return v;
 320                                         else
 321                                                 return new EnumConstant (v, result_type);
 322                                 } else if (left is ULongConstant){
 323                                         ULongConstant v;
 324                                         ulong res = ((ULongConstant)left).Value ^
 325                                                 ((ULongConstant)right).Value;
 326
 327                                         v = new ULongConstant (res);
 328                                         if (result_type == null)
 329                                                 return v;
 330                                         else
 331                                                 return new EnumConstant (v, result_type);
 332                                 }
 333                                 break;
 334
 335                         case Binary.Operator.Addition:
 336                                 Constant result;
 337                                 bool left_is_string = left is StringConstant;
 338                                 bool right_is_string = right is StringConstant;
 339
 340                                 //
 341                                 // If both sides are strings, then concatenate, if
 342                                 // one is a string, and the other is not, then defer
 343                                 // to runtime concatenation
 344                                 //
 345                                 if (left_is_string || right_is_string){
 346                                         if (left_is_string && right_is_string)
 347                                                 return new StringConstant (
 348                                                         ((StringConstant) left).Value +
 349                                                         ((StringConstant) right).Value);
 350
 351                                         return null;
 352                                 }
 353
 354                                 //
 355                                 // handle "E operator + (E x, U y)"
 356                                 // handle "E operator + (Y y, E x)"
 357                                 //
 358                                 // note that E operator + (E x, E y) is invalid
 359                                 //
 360                                 Type wrap_as = null;
 361                                 if (left is EnumConstant){
 362                                         if (right is EnumConstant){
 363                                                 return null;
 364                                         }
 365                                         if (((EnumConstant) left).Child.Type != right.Type)
 366                                                 return null;
 367
 368                                         wrap_as = left.Type;
 369                                 } else if (right is EnumConstant){
 370                                         if (((EnumConstant) right).Child.Type != left.Type)
 371                                                 return null;
 372                                         wrap_as = right.Type;
 373                                 }
 374
 375                                 result = null;
 376                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 377                                 if (left == null || right == null)
 378                                         return null;
 379
 380                                 try {
 381                                         if (left is DoubleConstant){
 382                                                 double res;
 383
 384                                                 if (ec.ConstantCheckState)
 385                                                         res = checked (((DoubleConstant) left).Value +
 386                                                                        ((DoubleConstant) right).Value);
 387                                                 else
 388                                                         res = unchecked (((DoubleConstant) left).Value +
 389                                                                          ((DoubleConstant) right).Value);
 390
 391                                                 result = new DoubleConstant (res);
 392                                         } else if (left is FloatConstant){
 393                                                 float res;
 394
 395                                                 if (ec.ConstantCheckState)
 396                                                         res = checked (((FloatConstant) left).Value +
 397                                                                        ((FloatConstant) right).Value);
 398                                                 else
 399                                                         res = unchecked (((FloatConstant) left).Value +
 400                                                                          ((FloatConstant) right).Value);
 401
 402                                                 result = new FloatConstant (res);
 403                                         } else if (left is ULongConstant){
 404                                                 ulong res;
 405
 406                                                 if (ec.ConstantCheckState)
 407                                                         res = checked (((ULongConstant) left).Value +
 408                                                                        ((ULongConstant) right).Value);
 409                                                 else
 410                                                         res = unchecked (((ULongConstant) left).Value +
 411                                                                          ((ULongConstant) right).Value);
 412
 413                                                 result = new ULongConstant (res);
 414                                         } else if (left is LongConstant){
 415                                                 long res;
 416
 417                                                 if (ec.ConstantCheckState)
 418                                                         res = checked (((LongConstant) left).Value +
 419                                                                        ((LongConstant) right).Value);
 420                                                 else
 421                                                         res = unchecked (((LongConstant) left).Value +
 422                                                                          ((LongConstant) right).Value);
 423
 424                                                 result = new LongConstant (res);
 425                                         } else if (left is UIntConstant){
 426                                                 uint res;
 427
 428                                                 if (ec.ConstantCheckState)
 429                                                         res = checked (((UIntConstant) left).Value +
 430                                                                        ((UIntConstant) right).Value);
 431                                                 else
 432                                                         res = unchecked (((UIntConstant) left).Value +
 433                                                                          ((UIntConstant) right).Value);
 434
 435                                                 result = new UIntConstant (res);
 436                                         } else if (left is IntConstant){
 437                                                 int res;
 438
 439                                                 if (ec.ConstantCheckState)
 440                                                         res = checked (((IntConstant) left).Value +
 441                                                                        ((IntConstant) right).Value);
 442                                                 else
 443                                                         res = unchecked (((IntConstant) left).Value +
 444                                                                          ((IntConstant) right).Value);
 445
 446                                                 result = new IntConstant (res);
 447                                         } else {
 448                                                 throw new Exception ( "Unexepected input: " + left);
 449                                         }
 450                                 } catch (OverflowException){
 451                                         Error_CompileTimeOverflow (loc);
 452                                 }
 453
 454                                 if (wrap_as != null)
 455                                         return new EnumConstant (result, wrap_as);
 456                                 else
 457                                         return result;
 458
 459                         case Binary.Operator.Subtraction:
 460                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 461                                 if (left == null || right == null)
 462                                         return null;
 463
 464                                 try {
 465                                         if (left is DoubleConstant){
 466                                                 double res;
 467
 468                                                 if (ec.ConstantCheckState)
 469                                                         res = checked (((DoubleConstant) left).Value -
 470                                                                        ((DoubleConstant) right).Value);
 471                                                 else
 472                                                         res = unchecked (((DoubleConstant) left).Value -
 473                                                                          ((DoubleConstant) right).Value);
 474
 475                                                 return new DoubleConstant (res);
 476                                         } else if (left is FloatConstant){
 477                                                 float res;
 478
 479                                                 if (ec.ConstantCheckState)
 480                                                         res = checked (((FloatConstant) left).Value -
 481                                                                        ((FloatConstant) right).Value);
 482                                                 else
 483                                                         res = unchecked (((FloatConstant) left).Value -
 484                                                                          ((FloatConstant) right).Value);
 485
 486                                                 return new FloatConstant (res);
 487                                         } else if (left is ULongConstant){
 488                                                 ulong res;
 489
 490                                                 if (ec.ConstantCheckState)
 491                                                         res = checked (((ULongConstant) left).Value -
 492                                                                        ((ULongConstant) right).Value);
 493                                                 else
 494                                                         res = unchecked (((ULongConstant) left).Value -
 495                                                                          ((ULongConstant) right).Value);
 496
 497                                                 return new ULongConstant (res);
 498                                         } else if (left is LongConstant){
 499                                                 long res;
 500
 501                                                 if (ec.ConstantCheckState)
 502                                                         res = checked (((LongConstant) left).Value -
 503                                                                        ((LongConstant) right).Value);
 504                                                 else
 505                                                         res = unchecked (((LongConstant) left).Value -
 506                                                                          ((LongConstant) right).Value);
 507
 508                                                 return new LongConstant (res);
 509                                         } else if (left is UIntConstant){
 510                                                 uint res;
 511
 512                                                 if (ec.ConstantCheckState)
 513                                                         res = checked (((UIntConstant) left).Value -
 514                                                                        ((UIntConstant) right).Value);
 515                                                 else
 516                                                         res = unchecked (((UIntConstant) left).Value -
 517                                                                          ((UIntConstant) right).Value);
 518
 519                                                 return new UIntConstant (res);
 520                                         } else if (left is IntConstant){
 521                                                 int res;
 522
 523                                                 if (ec.ConstantCheckState)
 524                                                         res = checked (((IntConstant) left).Value -
 525                                                                        ((IntConstant) right).Value);
 526                                                 else
 527                                                         res = unchecked (((IntConstant) left).Value -
 528                                                                          ((IntConstant) right).Value);
 529
 530                                                 return new IntConstant (res);
 531                                         } else {
 532                                                 throw new Exception ( "Unexepected input: " + left);
 533                                         }
 534                                 } catch (OverflowException){
 535                                         Error_CompileTimeOverflow (loc);
 536                                 }
 537                                 break;
 538
 539                         case Binary.Operator.Multiply:
 540                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 541                                 if (left == null || right == null)
 542                                         return null;
 543
 544                                 try {
 545                                         if (left is DoubleConstant){
 546                                                 double res;
 547
 548                                                 if (ec.ConstantCheckState)
 549                                                         res = checked (((DoubleConstant) left).Value *
 550                                                                        ((DoubleConstant) right).Value);
 551                                                 else
 552                                                         res = unchecked (((DoubleConstant) left).Value *
 553                                                                          ((DoubleConstant) right).Value);
 554
 555                                                 return new DoubleConstant (res);
 556                                         } else if (left is FloatConstant){
 557                                                 float res;
 558
 559                                                 if (ec.ConstantCheckState)
 560                                                         res = checked (((FloatConstant) left).Value *
 561                                                                        ((FloatConstant) right).Value);
 562                                                 else
 563                                                         res = unchecked (((FloatConstant) left).Value *
 564                                                                          ((FloatConstant) right).Value);
 565
 566                                                 return new FloatConstant (res);
 567                                         } else if (left is ULongConstant){
 568                                                 ulong res;
 569
 570                                                 if (ec.ConstantCheckState)
 571                                                         res = checked (((ULongConstant) left).Value *
 572                                                                        ((ULongConstant) right).Value);
 573                                                 else
 574                                                         res = unchecked (((ULongConstant) left).Value *
 575                                                                          ((ULongConstant) right).Value);
 576
 577                                                 return new ULongConstant (res);
 578                                         } else if (left is LongConstant){
 579                                                 long res;
 580
 581                                                 if (ec.ConstantCheckState)
 582                                                         res = checked (((LongConstant) left).Value *
 583                                                                        ((LongConstant) right).Value);
 584                                                 else
 585                                                         res = unchecked (((LongConstant) left).Value *
 586                                                                          ((LongConstant) right).Value);
 587
 588                                                 return new LongConstant (res);
 589                                         } else if (left is UIntConstant){
 590                                                 uint res;
 591
 592                                                 if (ec.ConstantCheckState)
 593                                                         res = checked (((UIntConstant) left).Value *
 594                                                                        ((UIntConstant) right).Value);
 595                                                 else
 596                                                         res = unchecked (((UIntConstant) left).Value *
 597                                                                          ((UIntConstant) right).Value);
 598
 599                                                 return new UIntConstant (res);
 600                                         } else if (left is IntConstant){
 601                                                 int res;
 602
 603                                                 if (ec.ConstantCheckState)
 604                                                         res = checked (((IntConstant) left).Value *
 605                                                                        ((IntConstant) right).Value);
 606                                                 else
 607                                                         res = unchecked (((IntConstant) left).Value *
 608                                                                          ((IntConstant) right).Value);
 609
 610                                                 return new IntConstant (res);
 611                                         } else {
 612                                                 throw new Exception ( "Unexepected input: " + left);
 613                                         }
 614                                 } catch (OverflowException){
 615                                         Error_CompileTimeOverflow (loc);
 616                                 }
 617                                 break;
 618
 619                         case Binary.Operator.Division:
 620                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 621                                 if (left == null || right == null)
 622                                         return null;
 623
 624                                 try {
 625                                         if (left is DoubleConstant){
 626                                                 double res;
 627
 628                                                 if (ec.ConstantCheckState)
 629                                                         res = checked (((DoubleConstant) left).Value /
 630                                                                        ((DoubleConstant) right).Value);
 631                                                 else
 632                                                         res = unchecked (((DoubleConstant) left).Value /
 633                                                                          ((DoubleConstant) right).Value);
 634
 635                                                 return new DoubleConstant (res);
 636                                         } else if (left is FloatConstant){
 637                                                 float res;
 638
 639                                                 if (ec.ConstantCheckState)
 640                                                         res = checked (((FloatConstant) left).Value /
 641                                                                        ((FloatConstant) right).Value);
 642                                                 else
 643                                                         res = unchecked (((FloatConstant) left).Value /
 644                                                                          ((FloatConstant) right).Value);
 645
 646                                                 return new FloatConstant (res);
 647                                         } else if (left is ULongConstant){
 648                                                 ulong res;
 649
 650                                                 if (ec.ConstantCheckState)
 651                                                         res = checked (((ULongConstant) left).Value /
 652                                                                        ((ULongConstant) right).Value);
 653                                                 else
 654                                                         res = unchecked (((ULongConstant) left).Value /
 655                                                                          ((ULongConstant) right).Value);
 656
 657                                                 return new ULongConstant (res);
 658                                         } else if (left is LongConstant){
 659                                                 long res;
 660
 661                                                 if (ec.ConstantCheckState)
 662                                                         res = checked (((LongConstant) left).Value /
 663                                                                        ((LongConstant) right).Value);
 664                                                 else
 665                                                         res = unchecked (((LongConstant) left).Value /
 666                                                                          ((LongConstant) right).Value);
 667
 668                                                 return new LongConstant (res);
 669                                         } else if (left is UIntConstant){
 670                                                 uint res;
 671
 672                                                 if (ec.ConstantCheckState)
 673                                                         res = checked (((UIntConstant) left).Value /
 674                                                                        ((UIntConstant) right).Value);
 675                                                 else
 676                                                         res = unchecked (((UIntConstant) left).Value /
 677                                                                          ((UIntConstant) right).Value);
 678
 679                                                 return new UIntConstant (res);
 680                                         } else if (left is IntConstant){
 681                                                 int res;
 682
 683                                                 if (ec.ConstantCheckState)
 684                                                         res = checked (((IntConstant) left).Value /
 685                                                                        ((IntConstant) right).Value);
 686                                                 else
 687                                                         res = unchecked (((IntConstant) left).Value /
 688                                                                          ((IntConstant) right).Value);
 689
 690                                                 return new IntConstant (res);
 691                                         } else {
 692                                                 throw new Exception ( "Unexepected input: " + left);
 693                                         }
 694                                 } catch (OverflowException){
 695                                         Error_CompileTimeOverflow (loc);
 696
 697                                 } catch (DivideByZeroException) {
 698                                         Report.Error (020, loc, "Division by constant zero");
 699                                 }
 700
 701                                 break;
 702
 703                         case Binary.Operator.Modulus:
 704                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 705                                 if (left == null || right == null)
 706                                         return null;
 707
 708                                 try {
 709                                         if (left is DoubleConstant){
 710                                                 double res;
 711
 712                                                 if (ec.ConstantCheckState)
 713                                                         res = checked (((DoubleConstant) left).Value %
 714                                                                        ((DoubleConstant) right).Value);
 715                                                 else
 716                                                         res = unchecked (((DoubleConstant) left).Value %
 717                                                                          ((DoubleConstant) right).Value);
 718
 719                                                 return new DoubleConstant (res);
 720                                         } else if (left is FloatConstant){
 721                                                 float res;
 722
 723                                                 if (ec.ConstantCheckState)
 724                                                         res = checked (((FloatConstant) left).Value %
 725                                                                        ((FloatConstant) right).Value);
 726                                                 else
 727                                                         res = unchecked (((FloatConstant) left).Value %
 728                                                                          ((FloatConstant) right).Value);
 729
 730                                                 return new FloatConstant (res);
 731                                         } else if (left is ULongConstant){
 732                                                 ulong res;
 733
 734                                                 if (ec.ConstantCheckState)
 735                                                         res = checked (((ULongConstant) left).Value %
 736                                                                        ((ULongConstant) right).Value);
 737                                                 else
 738                                                         res = unchecked (((ULongConstant) left).Value %
 739                                                                          ((ULongConstant) right).Value);
 740
 741                                                 return new ULongConstant (res);
 742                                         } else if (left is LongConstant){
 743                                                 long res;
 744
 745                                                 if (ec.ConstantCheckState)
 746                                                         res = checked (((LongConstant) left).Value %
 747                                                                        ((LongConstant) right).Value);
 748                                                 else
 749                                                         res = unchecked (((LongConstant) left).Value %
 750                                                                          ((LongConstant) right).Value);
 751
 752                                                 return new LongConstant (res);
 753                                         } else if (left is UIntConstant){
 754                                                 uint res;
 755
 756                                                 if (ec.ConstantCheckState)
 757                                                         res = checked (((UIntConstant) left).Value %
 758                                                                        ((UIntConstant) right).Value);
 759                                                 else
 760                                                         res = unchecked (((UIntConstant) left).Value %
 761                                                                          ((UIntConstant) right).Value);
 762
 763                                                 return new UIntConstant (res);
 764                                         } else if (left is IntConstant){
 765                                                 int res;
 766
 767                                                 if (ec.ConstantCheckState)
 768                                                         res = checked (((IntConstant) left).Value %
 769                                                                        ((IntConstant) right).Value);
 770                                                 else
 771                                                         res = unchecked (((IntConstant) left).Value %
 772                                                                          ((IntConstant) right).Value);
 773
 774                                                 return new IntConstant (res);
 775                                         } else {
 776                                                 throw new Exception ( "Unexepected input: " + left);
 777                                         }
 778                                 } catch (OverflowException){
 779                                         Error_CompileTimeOverflow (loc);
 780                                 }
 781                                 break;
 782
 783                                 //
 784                                 // There is no overflow checking on left shift
 785                                 //
 786                         case Binary.Operator.LeftShift:
 787                                 IntConstant ic = right.ToInt (loc);
 788                                 if (ic == null){
 789                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 790                                         return null;
 791                                 }
 792                                 int lshift_val = ic.Value;
 793
 794                                 IntConstant lic;
 795                                 if ((lic = left.ConvertToInt ()) != null)
 796                                         return new IntConstant (lic.Value << lshift_val);
 797
 798                                 UIntConstant luic;
 799                                 if ((luic = left.ConvertToUInt ()) != null)
 800                                         return new UIntConstant (luic.Value << lshift_val);
 801
 802                                 LongConstant llc;
 803                                 if ((llc = left.ConvertToLong ()) != null)
 804                                         return new LongConstant (llc.Value << lshift_val);
 805
 806                                 ULongConstant lulc;
 807                                 if ((lulc = left.ConvertToULong ()) != null)
 808                                         return new ULongConstant (lulc.Value << lshift_val);
 809
 810                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 811                                 break;
 812
 813                                 //
 814                                 // There is no overflow checking on right shift
 815                                 //
 816                         case Binary.Operator.RightShift:
 817                                 IntConstant sic = right.ToInt (loc);
 818                                 if (sic == null){
 819                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 820                                         return null;
 821                                 }
 822                                 int rshift_val = sic.Value;
 823
 824                                 IntConstant ric;
 825                                 if ((ric = left.ConvertToInt ()) != null)
 826                                         return new IntConstant (ric.Value >> rshift_val);
 827
 828                                 UIntConstant ruic;
 829                                 if ((ruic = left.ConvertToUInt ()) != null)
 830                                         return new UIntConstant (ruic.Value >> rshift_val);
 831
 832                                 LongConstant rlc;
 833                                 if ((rlc = left.ConvertToLong ()) != null)
 834                                         return new LongConstant (rlc.Value >> rshift_val);
 835
 836                                 ULongConstant rulc;
 837                                 if ((rulc = left.ConvertToULong ()) != null)
 838                                         return new ULongConstant (rulc.Value >> rshift_val);
 839
 840                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 841                                 break;
 842
 843                         case Binary.Operator.LogicalAnd:
 844                                 if (left is BoolConstant && right is BoolConstant){
 845                                         return new BoolConstant (
 846                                                 ((BoolConstant) left).Value &&
 847                                                 ((BoolConstant) right).Value);
 848                                 }
 849                                 break;
 850
 851                         case Binary.Operator.LogicalOr:
 852                                 if (left is BoolConstant && right is BoolConstant){
 853                                         return new BoolConstant (
 854                                                 ((BoolConstant) left).Value ||
 855                                                 ((BoolConstant) right).Value);
 856                                 }
 857                                 break;
 858
 859                         case Binary.Operator.Equality:
 860                                 if (left is BoolConstant && right is BoolConstant){
 861                                         return new BoolConstant (
 862                                                 ((BoolConstant) left).Value ==
 863                                                 ((BoolConstant) right).Value);
 864
 865                                 }
 866                                 if (left is StringConstant && right is StringConstant){
 867                                         return new BoolConstant (
 868                                                 ((StringConstant) left).Value ==
 869                                                 ((StringConstant) right).Value);
 870
 871                                 }
 872
 873                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 874                                 if (left == null || right == null)
 875                                         return null;
 876
 877                                 bool_res = false;
 878                                 if (left is DoubleConstant)
 879                                         bool_res = ((DoubleConstant) left).Value ==
 880                                                 ((DoubleConstant) right).Value;
 881                                 else if (left is FloatConstant)
 882                                         bool_res = ((FloatConstant) left).Value ==
 883                                                 ((FloatConstant) right).Value;
 884                                 else if (left is ULongConstant)
 885                                         bool_res = ((ULongConstant) left).Value ==
 886                                                 ((ULongConstant) right).Value;
 887                                 else if (left is LongConstant)
 888                                         bool_res = ((LongConstant) left).Value ==
 889                                                 ((LongConstant) right).Value;
 890                                 else if (left is UIntConstant)
 891                                         bool_res = ((UIntConstant) left).Value ==
 892                                                 ((UIntConstant) right).Value;
 893                                 else if (left is IntConstant)
 894                                         bool_res = ((IntConstant) left).Value ==
 895                                                 ((IntConstant) right).Value;
 896                                 else
 897                                         return null;
 898
 899                                 return new BoolConstant (bool_res);
 900
 901                         case Binary.Operator.Inequality:
 902                                 if (left is BoolConstant && right is BoolConstant){
 903                                         return new BoolConstant (
 904                                                 ((BoolConstant) left).Value !=
 905                                                 ((BoolConstant) right).Value);
 906                                 }
 907                                 if (left is StringConstant && right is StringConstant){
 908                                         return new BoolConstant (
 909                                                 ((StringConstant) left).Value !=
 910                                                 ((StringConstant) right).Value);
 911
 912                                 }
 913                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 914                                 if (left == null || right == null)
 915                                         return null;
 916
 917                                 bool_res = false;
 918                                 if (left is DoubleConstant)
 919                                         bool_res = ((DoubleConstant) left).Value !=
 920                                                 ((DoubleConstant) right).Value;
 921                                 else if (left is FloatConstant)
 922                                         bool_res = ((FloatConstant) left).Value !=
 923                                                 ((FloatConstant) right).Value;
 924                                 else if (left is ULongConstant)
 925                                         bool_res = ((ULongConstant) left).Value !=
 926                                                 ((ULongConstant) right).Value;
 927                                 else if (left is LongConstant)
 928                                         bool_res = ((LongConstant) left).Value !=
 929                                                 ((LongConstant) right).Value;
 930                                 else if (left is UIntConstant)
 931                                         bool_res = ((UIntConstant) left).Value !=
 932                                                 ((UIntConstant) right).Value;
 933                                 else if (left is IntConstant)
 934                                         bool_res = ((IntConstant) left).Value !=
 935                                                 ((IntConstant) right).Value;
 936                                 else
 937                                         return null;
 938
 939                                 return new BoolConstant (bool_res);
 940
 941                         case Binary.Operator.LessThan:
 942                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 943                                 if (left == null || right == null)
 944                                         return null;
 945
 946                                 bool_res = false;
 947                                 if (left is DoubleConstant)
 948                                         bool_res = ((DoubleConstant) left).Value <
 949                                                 ((DoubleConstant) right).Value;
 950                                 else if (left is FloatConstant)
 951                                         bool_res = ((FloatConstant) left).Value <
 952                                                 ((FloatConstant) right).Value;
 953                                 else if (left is ULongConstant)
 954                                         bool_res = ((ULongConstant) left).Value <
 955                                                 ((ULongConstant) right).Value;
 956                                 else if (left is LongConstant)
 957                                         bool_res = ((LongConstant) left).Value <
 958                                                 ((LongConstant) right).Value;
 959                                 else if (left is UIntConstant)
 960                                         bool_res = ((UIntConstant) left).Value <
 961                                                 ((UIntConstant) right).Value;
 962                                 else if (left is IntConstant)
 963                                         bool_res = ((IntConstant) left).Value <
 964                                                 ((IntConstant) right).Value;
 965                                 else
 966                                         return null;
 967
 968                                 return new BoolConstant (bool_res);
 969
 970                         case Binary.Operator.GreaterThan:
 971                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 972                                 if (left == null || right == null)
 973                                         return null;
 974
 975                                 bool_res = false;
 976                                 if (left is DoubleConstant)
 977                                         bool_res = ((DoubleConstant) left).Value >
 978                                                 ((DoubleConstant) right).Value;
 979                                 else if (left is FloatConstant)
 980                                         bool_res = ((FloatConstant) left).Value >
 981                                                 ((FloatConstant) right).Value;
 982                                 else if (left is ULongConstant)
 983                                         bool_res = ((ULongConstant) left).Value >
 984                                                 ((ULongConstant) right).Value;
 985                                 else if (left is LongConstant)
 986                                         bool_res = ((LongConstant) left).Value >
 987                                                 ((LongConstant) right).Value;
 988                                 else if (left is UIntConstant)
 989                                         bool_res = ((UIntConstant) left).Value >
 990                                                 ((UIntConstant) right).Value;
 991                                 else if (left is IntConstant)
 992                                         bool_res = ((IntConstant) left).Value >
 993                                                 ((IntConstant) right).Value;
 994                                 else
 995                                         return null;
 996
 997                                 return new BoolConstant (bool_res);
 998
 999                         case Binary.Operator.GreaterThanOrEqual:
1000                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1001                                 if (left == null || right == null)
1002                                         return null;
1003
1004                                 bool_res = false;
1005                                 if (left is DoubleConstant)
1006                                         bool_res = ((DoubleConstant) left).Value >=
1007                                                 ((DoubleConstant) right).Value;
1008                                 else if (left is FloatConstant)
1009                                         bool_res = ((FloatConstant) left).Value >=
1010                                                 ((FloatConstant) right).Value;
1011                                 else if (left is ULongConstant)
1012                                         bool_res = ((ULongConstant) left).Value >=
1013                                                 ((ULongConstant) right).Value;
1014                                 else if (left is LongConstant)
1015                                         bool_res = ((LongConstant) left).Value >=
1016                                                 ((LongConstant) right).Value;
1017                                 else if (left is UIntConstant)
1018                                         bool_res = ((UIntConstant) left).Value >=
1019                                                 ((UIntConstant) right).Value;
1020                                 else if (left is IntConstant)
1021                                         bool_res = ((IntConstant) left).Value >=
1022                                                 ((IntConstant) right).Value;
1023                                 else
1024                                         return null;
1025
1026                                 return new BoolConstant (bool_res);
1027
1028                         case Binary.Operator.LessThanOrEqual:
1029                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1030                                 if (left == null || right == null)
1031                                         return null;
1032
1033                                 bool_res = false;
1034                                 if (left is DoubleConstant)
1035                                         bool_res = ((DoubleConstant) left).Value <=
1036                                                 ((DoubleConstant) right).Value;
1037                                 else if (left is FloatConstant)
1038                                         bool_res = ((FloatConstant) left).Value <=
1039                                                 ((FloatConstant) right).Value;
1040                                 else if (left is ULongConstant)
1041                                         bool_res = ((ULongConstant) left).Value <=
1042                                                 ((ULongConstant) right).Value;
1043                                 else if (left is LongConstant)
1044                                         bool_res = ((LongConstant) left).Value <=
1045                                                 ((LongConstant) right).Value;
1046                                 else if (left is UIntConstant)
1047                                         bool_res = ((UIntConstant) left).Value <=
1048                                                 ((UIntConstant) right).Value;
1049                                 else if (left is IntConstant)
1050                                         bool_res = ((IntConstant) left).Value <=
1051                                                 ((IntConstant) right).Value;
1052                                 else
1053                                         return null;
1054
1055                                 return new BoolConstant (bool_res);
1056                         }
1057
1058                         return null;
1059                 }
1060         }
1061 }