mcs/mcs/cfold.cs

   1 //
   2 // cfold.cs: Constant Folding
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2002, 2003 Ximian, Inc.
   8 //
   9
  10 using System;
  11
  12 namespace Mono.CSharp {
  13
  14         public class ConstantFold {
  15
  16                 //
  17                 // Performs the numeric promotions on the left and right expresions
  18                 // and desposits the results on `lc' and `rc'.
  19                 //
  20                 // On success, the types of `lc' and `rc' on output will always match,
  21                 // and the pair will be one of:
  22                 //
  23                 //   (double, double)
  24                 //   (float, float)
  25                 //   (ulong, ulong)
  26                 //   (long, long)
  27                 //   (uint, uint)
  28                 //   (int, int)
  29                 //   (short, short)   (Happens with enumerations with underlying short type)
  30                 //   (ushort, ushort) (Happens with enumerations with underlying short type)
  31                 //
  32                 static void DoConstantNumericPromotions (EmitContext ec, Binary.Operator oper,
  33                                                          ref Constant left, ref Constant right,
  34                                                          Location loc)
  35                 {
  36                         if (left is DoubleConstant || right is DoubleConstant){
  37                                 //
  38                                 // If either side is a double, convert the other to a double
  39                                 //
  40                                 if (!(left is DoubleConstant))
  41                                         left = left.ToDouble (loc);
  42
  43                                 if (!(right is DoubleConstant))
  44                                         right = right.ToDouble (loc);
  45                                 return;
  46                         } else if (left is FloatConstant || right is FloatConstant) {
  47                                 //
  48                                 // If either side is a float, convert the other to a float
  49                                 //
  50                                 if (!(left is FloatConstant))
  51                                         left = left.ToFloat (loc);
  52
  53                                 if (!(right is FloatConstant))
  54                                         right = right.ToFloat (loc);
  55 ;                               return;
  56                         } else if (left is ULongConstant || right is ULongConstant){
  57                                 //
  58                                 // If either operand is of type ulong, the other operand is
  59                                 // converted to type ulong.  or an error ocurrs if the other
  60                                 // operand is of type sbyte, short, int or long
  61                                 //
  62                                 Constant match, other;
  63
  64                                 if (left is ULongConstant){
  65                                         other = right;
  66                                         match = left;
  67                                         if (!(right is ULongConstant))
  68                                                 right = right.ToULong (loc);
  69                                 } else {
  70                                         other = left;
  71                                         match = right;
  72                                         left = left.ToULong (loc);
  73                                 }
  74
  75 #if WRONG
  76                                 if (other is SByteConstant || other is ShortConstant ||
  77                                     other is IntConstant || other is LongConstant){
  78                                         Binary.Error_OperatorAmbiguous
  79                                                 (loc, oper, other.Type, match.Type);
  80                                         left = null;
  81                                         right = null;
  82                                 }
  83 #endif
  84                                 return;
  85                         } else if (left is LongConstant || right is LongConstant){
  86                                 //
  87                                 // If either operand is of type long, the other operand is converted
  88                                 // to type long.
  89                                 //
  90                                 if (!(left is LongConstant))
  91                                         left = left.ToLong (loc);
  92                                 else if (!(right is LongConstant))
  93                                         right = right.ToLong (loc);
  94                                 return;
  95                         } else if (left is UIntConstant || right is UIntConstant){
  96                                 //
  97                                 // If either operand is of type uint, and the other
  98                                 // operand is of type sbyte, short or int, the operands are
  99                                 // converted to type long.
 100                                 //
 101                                 Constant other;
 102                                 if (left is UIntConstant)
 103                                         other = right;
 104                                 else
 105                                         other = left;
 106
 107                                 // Nothing to do.
 108                                 if (other is UIntConstant)
 109                                         return;
 110
 111                                 IntConstant ic = other as IntConstant;
 112                                 if (ic != null){
 113                                         if (ic.Value >= 0){
 114                                                 if (left == other)
 115                                                         left = new UIntConstant ((uint) ic.Value);
 116                                                 else
 117                                                         right = new UIntConstant ((uint) ic.Value);
 118                                                 return;
 119                                         }
 120                                 }
 121
 122                                 if (other is SByteConstant || other is ShortConstant || ic != null){
 123                                         left = left.ToLong (loc);
 124                                         right = right.ToLong (loc);
 125                                 }
 126
 127                                 return;
 128                         } else if (left is EnumConstant || right is EnumConstant){
 129                                 //
 130                                 // If either operand is an enum constant, the other one must
 131                                 // be implicitly convertable to that enum's underlying type.
 132                                 //
 133                                 EnumConstant match;
 134                                 Constant other;
 135                                 if (left is EnumConstant){
 136                                         other = right;
 137                                         match = (EnumConstant) left;
 138                                 } else {
 139                                         other = left;
 140                                         match = (EnumConstant) right;
 141                                 }
 142
 143                                 bool need_check = (other is EnumConstant) ||
 144                                         ((oper != Binary.Operator.Addition) &&
 145                                          (oper != Binary.Operator.Subtraction));
 146
 147                                 if (need_check &&
 148                                     !Convert.ImplicitConversionExists (ec, match, other.Type)) {
 149                                         Convert.Error_CannotImplicitConversion (loc, match.Type, other.Type);
 150                                         left = null;
 151                                         right = null;
 152                                         return;
 153                                 }
 154
 155                                 if (left is EnumConstant)
 156                                         left = ((EnumConstant) left).Child;
 157                                 if (right is EnumConstant)
 158                                         right = ((EnumConstant) right).Child;
 159                                 return;
 160
 161                         } else {
 162                                 //
 163                                 // Force conversions to int32
 164                                 //
 165                                 if (!(left is IntConstant))
 166                                         left = left.ToInt (loc);
 167                                 if (!(right is IntConstant))
 168                                         right = right.ToInt (loc);
 169                         }
 170                         return;
 171                 }
 172
 173                 static void Error_CompileTimeOverflow (Location loc)
 174                 {
 175                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 176                 }
 177
 178                 /// <summary>
 179                 ///   Constant expression folder for binary operations.
 180                 ///
 181                 ///   Returns null if the expression can not be folded.
 182                 /// </summary>
 183                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 184                                                      Constant left, Constant right, Location loc)
 185                 {
 186                         Type lt = left.Type;
 187                         Type rt = right.Type;
 188                         Type result_type = null;
 189                         bool bool_res;
 190
 191                         //
 192                         // Enumerator folding
 193                         //
 194                         if (rt == lt && left is EnumConstant)
 195                                 result_type = lt;
 196
 197                         //
 198                         // During an enum evaluation, we need to unwrap enumerations
 199                         //
 200                         if (ec.InEnumContext){
 201                                 if (left is EnumConstant)
 202                                         left = ((EnumConstant) left).Child;
 203
 204                                 if (right is EnumConstant)
 205                                         right = ((EnumConstant) right).Child;
 206                         }
 207
 208                         Type wrap_as;
 209                         Constant result = null;
 210                         switch (oper){
 211                         case Binary.Operator.BitwiseOr:
 212                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 213                                 if (left == null || right == null)
 214                                         return null;
 215
 216                                 if (left is IntConstant){
 217                                         IntConstant v;
 218                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 219
 220                                         v = new IntConstant (res);
 221                                         if (result_type == null)
 222                                                 return v;
 223                                         else
 224                                                 return new EnumConstant (v, result_type);
 225                                 } else if (left is UIntConstant){
 226                                         UIntConstant v;
 227                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 228
 229                                         v = new UIntConstant (res);
 230                                         if (result_type == null)
 231                                                 return v;
 232                                         else
 233                                                 return new EnumConstant (v, result_type);
 234                                 } else if (left is LongConstant){
 235                                         LongConstant v;
 236                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 237
 238                                         v = new LongConstant (res);
 239                                         if (result_type == null)
 240                                                 return v;
 241                                         else
 242                                                 return new EnumConstant (v, result_type);
 243                                 } else if (left is ULongConstant){
 244                                         ULongConstant v;
 245                                         ulong res = ((ULongConstant)left).Value |
 246                                                 ((ULongConstant)right).Value;
 247
 248                                         v = new ULongConstant (res);
 249                                         if (result_type == null)
 250                                                 return v;
 251                                         else
 252                                                 return new EnumConstant (v, result_type);
 253                                 } else if (left is UShortConstant){
 254                                         UShortConstant v;
 255                                         ushort res = (ushort) (((UShortConstant)left).Value |
 256                                                                ((UShortConstant)right).Value);
 257
 258                                         v = new UShortConstant (res);
 259                                         if (result_type == null)
 260                                                 return v;
 261                                         else
 262                                                 return new EnumConstant (v, result_type);
 263                                 } else if (left is ShortConstant){
 264                                         ShortConstant v;
 265                                         short res = (short) (((ShortConstant)left).Value |
 266                                                              ((ShortConstant)right).Value);
 267
 268                                         v = new ShortConstant (res);
 269                                         if (result_type == null)
 270                                                 return v;
 271                                         else
 272                                                 return new EnumConstant (v, result_type);
 273                                 }
 274                                 break;
 275
 276                         case Binary.Operator.BitwiseAnd:
 277                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 278                                 if (left == null || right == null)
 279                                         return null;
 280
 281                                 if (left is IntConstant){
 282                                         IntConstant v;
 283                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 284
 285                                         v = new IntConstant (res);
 286                                         if (result_type == null)
 287                                                 return v;
 288                                         else
 289                                                 return new EnumConstant (v, result_type);
 290                                 } else if (left is UIntConstant){
 291                                         UIntConstant v;
 292                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 293
 294                                         v = new UIntConstant (res);
 295                                         if (result_type == null)
 296                                                 return v;
 297                                         else
 298                                                 return new EnumConstant (v, result_type);
 299                                 } else if (left is LongConstant){
 300                                         LongConstant v;
 301                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 302
 303                                         v = new LongConstant (res);
 304                                         if (result_type == null)
 305                                                 return v;
 306                                         else
 307                                                 return new EnumConstant (v, result_type);
 308                                 } else if (left is ULongConstant){
 309                                         ULongConstant v;
 310                                         ulong res = ((ULongConstant)left).Value &
 311                                                 ((ULongConstant)right).Value;
 312
 313                                         v = new ULongConstant (res);
 314                                         if (result_type == null)
 315                                                 return v;
 316                                         else
 317                                                 return new EnumConstant (v, result_type);
 318                                 } else if (left is UShortConstant){
 319                                         UShortConstant v;
 320                                         ushort res = (ushort) (((UShortConstant)left).Value &
 321                                                                ((UShortConstant)right).Value);
 322
 323                                         v = new UShortConstant (res);
 324                                         if (result_type == null)
 325                                                 return v;
 326                                         else
 327                                                 return new EnumConstant (v, result_type);
 328                                 } else if (left is ShortConstant){
 329                                         ShortConstant v;
 330                                         short res = (short) (((ShortConstant)left).Value &
 331                                                              ((ShortConstant)right).Value);
 332
 333                                         v = new ShortConstant (res);
 334                                         if (result_type == null)
 335                                                 return v;
 336                                         else
 337                                                 return new EnumConstant (v, result_type);
 338                                 }
 339                                 break;
 340
 341                         case Binary.Operator.ExclusiveOr:
 342                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 343                                 if (left == null || right == null)
 344                                         return null;
 345
 346                                 if (left is IntConstant){
 347                                         IntConstant v;
 348                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 349
 350                                         v = new IntConstant (res);
 351                                         if (result_type == null)
 352                                                 return v;
 353                                         else
 354                                                 return new EnumConstant (v, result_type);
 355                                 } else if (left is UIntConstant){
 356                                         UIntConstant v;
 357                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 358
 359                                         v = new UIntConstant (res);
 360                                         if (result_type == null)
 361                                                 return v;
 362                                         else
 363                                                 return new EnumConstant (v, result_type);
 364                                 } else if (left is LongConstant){
 365                                         LongConstant v;
 366                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 367
 368                                         v = new LongConstant (res);
 369                                         if (result_type == null)
 370                                                 return v;
 371                                         else
 372                                                 return new EnumConstant (v, result_type);
 373                                 } else if (left is ULongConstant){
 374                                         ULongConstant v;
 375                                         ulong res = ((ULongConstant)left).Value ^
 376                                                 ((ULongConstant)right).Value;
 377
 378                                         v = new ULongConstant (res);
 379                                         if (result_type == null)
 380                                                 return v;
 381                                         else
 382                                                 return new EnumConstant (v, result_type);
 383                                 } else if (left is UShortConstant){
 384                                         UShortConstant v;
 385                                         ushort res = (ushort) (((UShortConstant)left).Value ^
 386                                                                ((UShortConstant)right).Value);
 387
 388                                         v = new UShortConstant (res);
 389                                         if (result_type == null)
 390                                                 return v;
 391                                         else
 392                                                 return new EnumConstant (v, result_type);
 393                                 } else if (left is ShortConstant){
 394                                         ShortConstant v;
 395                                         short res = (short)(((ShortConstant)left).Value ^
 396                                                             ((ShortConstant)right).Value);
 397
 398                                         v = new ShortConstant (res);
 399                                         if (result_type == null)
 400                                                 return v;
 401                                         else
 402                                                 return new EnumConstant (v, result_type);
 403                                 }
 404                                 break;
 405
 406                         case Binary.Operator.Addition:
 407                                 bool left_is_string = left is StringConstant;
 408                                 bool right_is_string = right is StringConstant;
 409
 410                                 //
 411                                 // If both sides are strings, then concatenate, if
 412                                 // one is a string, and the other is not, then defer
 413                                 // to runtime concatenation
 414                                 //
 415                                 wrap_as = null;
 416                                 if (left_is_string || right_is_string){
 417                                         if (left_is_string && right_is_string)
 418                                                 return new StringConstant (
 419                                                         ((StringConstant) left).Value +
 420                                                         ((StringConstant) right).Value);
 421
 422                                         return null;
 423                                 }
 424
 425                                 //
 426                                 // handle "E operator + (E x, U y)"
 427                                 // handle "E operator + (Y y, E x)"
 428                                 //
 429                                 // note that E operator + (E x, E y) is invalid
 430                                 //
 431                                 if (left is EnumConstant){
 432                                         if (right is EnumConstant){
 433                                                 return null;
 434                                         }
 435                                         if (((EnumConstant) left).Child.Type != right.Type)
 436                                                 return null;
 437
 438                                         wrap_as = left.Type;
 439                                 } else if (right is EnumConstant){
 440                                         if (((EnumConstant) right).Child.Type != left.Type)
 441                                                 return null;
 442                                         wrap_as = right.Type;
 443                                 }
 444
 445                                 result = null;
 446                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 447                                 if (left == null || right == null)
 448                                         return null;
 449
 450                                 try {
 451                                         if (left is DoubleConstant){
 452                                                 double res;
 453
 454                                                 if (ec.ConstantCheckState)
 455                                                         res = checked (((DoubleConstant) left).Value +
 456                                                                        ((DoubleConstant) right).Value);
 457                                                 else
 458                                                         res = unchecked (((DoubleConstant) left).Value +
 459                                                                          ((DoubleConstant) right).Value);
 460
 461                                                 result = new DoubleConstant (res);
 462                                         } else if (left is FloatConstant){
 463                                                 float res;
 464
 465                                                 if (ec.ConstantCheckState)
 466                                                         res = checked (((FloatConstant) left).Value +
 467                                                                        ((FloatConstant) right).Value);
 468                                                 else
 469                                                         res = unchecked (((FloatConstant) left).Value +
 470                                                                          ((FloatConstant) right).Value);
 471
 472                                                 result = new FloatConstant (res);
 473                                         } else if (left is ULongConstant){
 474                                                 ulong res;
 475
 476                                                 if (ec.ConstantCheckState)
 477                                                         res = checked (((ULongConstant) left).Value +
 478                                                                        ((ULongConstant) right).Value);
 479                                                 else
 480                                                         res = unchecked (((ULongConstant) left).Value +
 481                                                                          ((ULongConstant) right).Value);
 482
 483                                                 result = new ULongConstant (res);
 484                                         } else if (left is LongConstant){
 485                                                 long res;
 486
 487                                                 if (ec.ConstantCheckState)
 488                                                         res = checked (((LongConstant) left).Value +
 489                                                                        ((LongConstant) right).Value);
 490                                                 else
 491                                                         res = unchecked (((LongConstant) left).Value +
 492                                                                          ((LongConstant) right).Value);
 493
 494                                                 result = new LongConstant (res);
 495                                         } else if (left is UIntConstant){
 496                                                 uint res;
 497
 498                                                 if (ec.ConstantCheckState)
 499                                                         res = checked (((UIntConstant) left).Value +
 500                                                                        ((UIntConstant) right).Value);
 501                                                 else
 502                                                         res = unchecked (((UIntConstant) left).Value +
 503                                                                          ((UIntConstant) right).Value);
 504
 505                                                 result = new UIntConstant (res);
 506                                         } else if (left is IntConstant){
 507                                                 int res;
 508
 509                                                 if (ec.ConstantCheckState)
 510                                                         res = checked (((IntConstant) left).Value +
 511                                                                        ((IntConstant) right).Value);
 512                                                 else
 513                                                         res = unchecked (((IntConstant) left).Value +
 514                                                                          ((IntConstant) right).Value);
 515
 516                                                 result = new IntConstant (res);
 517                                         } else {
 518                                                 throw new Exception ( "Unexepected input: " + left);
 519                                         }
 520                                 } catch (OverflowException){
 521                                         Error_CompileTimeOverflow (loc);
 522                                 }
 523
 524                                 if (wrap_as != null)
 525                                         return new EnumConstant (result, wrap_as);
 526                                 else
 527                                         return result;
 528
 529                         case Binary.Operator.Subtraction:
 530                                 //
 531                                 // handle "E operator - (E x, U y)"
 532                                 // handle "E operator - (Y y, E x)"
 533                                 // handle "U operator - (E x, E y)"
 534                                 //
 535                                 wrap_as = null;
 536                                 if (left is EnumConstant){
 537                                         if (right is EnumConstant){
 538                                                 if (left.Type == right.Type)
 539                                                         wrap_as = TypeManager.EnumToUnderlying (left.Type);
 540                                                 else
 541                                                         return null;
 542                                         }
 543                                         if (((EnumConstant) left).Child.Type != right.Type)
 544                                                 return null;
 545
 546                                         wrap_as = left.Type;
 547                                 } else if (right is EnumConstant){
 548                                         if (((EnumConstant) right).Child.Type != left.Type)
 549                                                 return null;
 550                                         wrap_as = right.Type;
 551                                 }
 552
 553                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 554                                 if (left == null || right == null)
 555                                         return null;
 556
 557                                 try {
 558                                         if (left is DoubleConstant){
 559                                                 double res;
 560
 561                                                 if (ec.ConstantCheckState)
 562                                                         res = checked (((DoubleConstant) left).Value -
 563                                                                        ((DoubleConstant) right).Value);
 564                                                 else
 565                                                         res = unchecked (((DoubleConstant) left).Value -
 566                                                                          ((DoubleConstant) right).Value);
 567
 568                                                 result = new DoubleConstant (res);
 569                                         } else if (left is FloatConstant){
 570                                                 float res;
 571
 572                                                 if (ec.ConstantCheckState)
 573                                                         res = checked (((FloatConstant) left).Value -
 574                                                                        ((FloatConstant) right).Value);
 575                                                 else
 576                                                         res = unchecked (((FloatConstant) left).Value -
 577                                                                          ((FloatConstant) right).Value);
 578
 579                                                 result = new FloatConstant (res);
 580                                         } else if (left is ULongConstant){
 581                                                 ulong res;
 582
 583                                                 if (ec.ConstantCheckState)
 584                                                         res = checked (((ULongConstant) left).Value -
 585                                                                        ((ULongConstant) right).Value);
 586                                                 else
 587                                                         res = unchecked (((ULongConstant) left).Value -
 588                                                                          ((ULongConstant) right).Value);
 589
 590                                                 result = new ULongConstant (res);
 591                                         } else if (left is LongConstant){
 592                                                 long res;
 593
 594                                                 if (ec.ConstantCheckState)
 595                                                         res = checked (((LongConstant) left).Value -
 596                                                                        ((LongConstant) right).Value);
 597                                                 else
 598                                                         res = unchecked (((LongConstant) left).Value -
 599                                                                          ((LongConstant) right).Value);
 600
 601                                                 result = new LongConstant (res);
 602                                         } else if (left is UIntConstant){
 603                                                 uint res;
 604
 605                                                 if (ec.ConstantCheckState)
 606                                                         res = checked (((UIntConstant) left).Value -
 607                                                                        ((UIntConstant) right).Value);
 608                                                 else
 609                                                         res = unchecked (((UIntConstant) left).Value -
 610                                                                          ((UIntConstant) right).Value);
 611
 612                                                 result = new UIntConstant (res);
 613                                         } else if (left is IntConstant){
 614                                                 int res;
 615
 616                                                 if (ec.ConstantCheckState)
 617                                                         res = checked (((IntConstant) left).Value -
 618                                                                        ((IntConstant) right).Value);
 619                                                 else
 620                                                         res = unchecked (((IntConstant) left).Value -
 621                                                                          ((IntConstant) right).Value);
 622
 623                                                 result = new IntConstant (res);
 624                                         } else {
 625                                                 throw new Exception ( "Unexepected input: " + left);
 626                                         }
 627                                 } catch (OverflowException){
 628                                         Error_CompileTimeOverflow (loc);
 629                                 }
 630                                 if (wrap_as != null)
 631                                         return new EnumConstant (result, wrap_as);
 632                                 else
 633                                         return result;
 634
 635                         case Binary.Operator.Multiply:
 636                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 637                                 if (left == null || right == null)
 638                                         return null;
 639
 640                                 try {
 641                                         if (left is DoubleConstant){
 642                                                 double res;
 643
 644                                                 if (ec.ConstantCheckState)
 645                                                         res = checked (((DoubleConstant) left).Value *
 646                                                                        ((DoubleConstant) right).Value);
 647                                                 else
 648                                                         res = unchecked (((DoubleConstant) left).Value *
 649                                                                          ((DoubleConstant) right).Value);
 650
 651                                                 return new DoubleConstant (res);
 652                                         } else if (left is FloatConstant){
 653                                                 float res;
 654
 655                                                 if (ec.ConstantCheckState)
 656                                                         res = checked (((FloatConstant) left).Value *
 657                                                                        ((FloatConstant) right).Value);
 658                                                 else
 659                                                         res = unchecked (((FloatConstant) left).Value *
 660                                                                          ((FloatConstant) right).Value);
 661
 662                                                 return new FloatConstant (res);
 663                                         } else if (left is ULongConstant){
 664                                                 ulong res;
 665
 666                                                 if (ec.ConstantCheckState)
 667                                                         res = checked (((ULongConstant) left).Value *
 668                                                                        ((ULongConstant) right).Value);
 669                                                 else
 670                                                         res = unchecked (((ULongConstant) left).Value *
 671                                                                          ((ULongConstant) right).Value);
 672
 673                                                 return new ULongConstant (res);
 674                                         } else if (left is LongConstant){
 675                                                 long res;
 676
 677                                                 if (ec.ConstantCheckState)
 678                                                         res = checked (((LongConstant) left).Value *
 679                                                                        ((LongConstant) right).Value);
 680                                                 else
 681                                                         res = unchecked (((LongConstant) left).Value *
 682                                                                          ((LongConstant) right).Value);
 683
 684                                                 return new LongConstant (res);
 685                                         } else if (left is UIntConstant){
 686                                                 uint res;
 687
 688                                                 if (ec.ConstantCheckState)
 689                                                         res = checked (((UIntConstant) left).Value *
 690                                                                        ((UIntConstant) right).Value);
 691                                                 else
 692                                                         res = unchecked (((UIntConstant) left).Value *
 693                                                                          ((UIntConstant) right).Value);
 694
 695                                                 return new UIntConstant (res);
 696                                         } else if (left is IntConstant){
 697                                                 int res;
 698
 699                                                 if (ec.ConstantCheckState)
 700                                                         res = checked (((IntConstant) left).Value *
 701                                                                        ((IntConstant) right).Value);
 702                                                 else
 703                                                         res = unchecked (((IntConstant) left).Value *
 704                                                                          ((IntConstant) right).Value);
 705
 706                                                 return new IntConstant (res);
 707                                         } else {
 708                                                 throw new Exception ( "Unexepected input: " + left);
 709                                         }
 710                                 } catch (OverflowException){
 711                                         Error_CompileTimeOverflow (loc);
 712                                 }
 713                                 break;
 714
 715                         case Binary.Operator.Division:
 716                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 717                                 if (left == null || right == null)
 718                                         return null;
 719
 720                                 try {
 721                                         if (left is DoubleConstant){
 722                                                 double res;
 723
 724                                                 if (ec.ConstantCheckState)
 725                                                         res = checked (((DoubleConstant) left).Value /
 726                                                                        ((DoubleConstant) right).Value);
 727                                                 else
 728                                                         res = unchecked (((DoubleConstant) left).Value /
 729                                                                          ((DoubleConstant) right).Value);
 730
 731                                                 return new DoubleConstant (res);
 732                                         } else if (left is FloatConstant){
 733                                                 float res;
 734
 735                                                 if (ec.ConstantCheckState)
 736                                                         res = checked (((FloatConstant) left).Value /
 737                                                                        ((FloatConstant) right).Value);
 738                                                 else
 739                                                         res = unchecked (((FloatConstant) left).Value /
 740                                                                          ((FloatConstant) right).Value);
 741
 742                                                 return new FloatConstant (res);
 743                                         } else if (left is ULongConstant){
 744                                                 ulong res;
 745
 746                                                 if (ec.ConstantCheckState)
 747                                                         res = checked (((ULongConstant) left).Value /
 748                                                                        ((ULongConstant) right).Value);
 749                                                 else
 750                                                         res = unchecked (((ULongConstant) left).Value /
 751                                                                          ((ULongConstant) right).Value);
 752
 753                                                 return new ULongConstant (res);
 754                                         } else if (left is LongConstant){
 755                                                 long res;
 756
 757                                                 if (ec.ConstantCheckState)
 758                                                         res = checked (((LongConstant) left).Value /
 759                                                                        ((LongConstant) right).Value);
 760                                                 else
 761                                                         res = unchecked (((LongConstant) left).Value /
 762                                                                          ((LongConstant) right).Value);
 763
 764                                                 return new LongConstant (res);
 765                                         } else if (left is UIntConstant){
 766                                                 uint res;
 767
 768                                                 if (ec.ConstantCheckState)
 769                                                         res = checked (((UIntConstant) left).Value /
 770                                                                        ((UIntConstant) right).Value);
 771                                                 else
 772                                                         res = unchecked (((UIntConstant) left).Value /
 773                                                                          ((UIntConstant) right).Value);
 774
 775                                                 return new UIntConstant (res);
 776                                         } else if (left is IntConstant){
 777                                                 int res;
 778
 779                                                 if (ec.ConstantCheckState)
 780                                                         res = checked (((IntConstant) left).Value /
 781                                                                        ((IntConstant) right).Value);
 782                                                 else
 783                                                         res = unchecked (((IntConstant) left).Value /
 784                                                                          ((IntConstant) right).Value);
 785
 786                                                 return new IntConstant (res);
 787                                         } else {
 788                                                 throw new Exception ( "Unexepected input: " + left);
 789                                         }
 790                                 } catch (OverflowException){
 791                                         Error_CompileTimeOverflow (loc);
 792
 793                                 } catch (DivideByZeroException) {
 794                                         Report.Error (020, loc, "Division by constant zero");
 795                                 }
 796
 797                                 break;
 798
 799                         case Binary.Operator.Modulus:
 800                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 801                                 if (left == null || right == null)
 802                                         return null;
 803
 804                                 try {
 805                                         if (left is DoubleConstant){
 806                                                 double res;
 807
 808                                                 if (ec.ConstantCheckState)
 809                                                         res = checked (((DoubleConstant) left).Value %
 810                                                                        ((DoubleConstant) right).Value);
 811                                                 else
 812                                                         res = unchecked (((DoubleConstant) left).Value %
 813                                                                          ((DoubleConstant) right).Value);
 814
 815                                                 return new DoubleConstant (res);
 816                                         } else if (left is FloatConstant){
 817                                                 float res;
 818
 819                                                 if (ec.ConstantCheckState)
 820                                                         res = checked (((FloatConstant) left).Value %
 821                                                                        ((FloatConstant) right).Value);
 822                                                 else
 823                                                         res = unchecked (((FloatConstant) left).Value %
 824                                                                          ((FloatConstant) right).Value);
 825
 826                                                 return new FloatConstant (res);
 827                                         } else if (left is ULongConstant){
 828                                                 ulong res;
 829
 830                                                 if (ec.ConstantCheckState)
 831                                                         res = checked (((ULongConstant) left).Value %
 832                                                                        ((ULongConstant) right).Value);
 833                                                 else
 834                                                         res = unchecked (((ULongConstant) left).Value %
 835                                                                          ((ULongConstant) right).Value);
 836
 837                                                 return new ULongConstant (res);
 838                                         } else if (left is LongConstant){
 839                                                 long res;
 840
 841                                                 if (ec.ConstantCheckState)
 842                                                         res = checked (((LongConstant) left).Value %
 843                                                                        ((LongConstant) right).Value);
 844                                                 else
 845                                                         res = unchecked (((LongConstant) left).Value %
 846                                                                          ((LongConstant) right).Value);
 847
 848                                                 return new LongConstant (res);
 849                                         } else if (left is UIntConstant){
 850                                                 uint res;
 851
 852                                                 if (ec.ConstantCheckState)
 853                                                         res = checked (((UIntConstant) left).Value %
 854                                                                        ((UIntConstant) right).Value);
 855                                                 else
 856                                                         res = unchecked (((UIntConstant) left).Value %
 857                                                                          ((UIntConstant) right).Value);
 858
 859                                                 return new UIntConstant (res);
 860                                         } else if (left is IntConstant){
 861                                                 int res;
 862
 863                                                 if (ec.ConstantCheckState)
 864                                                         res = checked (((IntConstant) left).Value %
 865                                                                        ((IntConstant) right).Value);
 866                                                 else
 867                                                         res = unchecked (((IntConstant) left).Value %
 868                                                                          ((IntConstant) right).Value);
 869
 870                                                 return new IntConstant (res);
 871                                         } else {
 872                                                 throw new Exception ( "Unexepected input: " + left);
 873                                         }
 874                                 } catch (DivideByZeroException){
 875                                         Report.Error (020, loc, "Division by constant zero");
 876                                 } catch (OverflowException){
 877                                         Error_CompileTimeOverflow (loc);
 878                                 }
 879                                 break;
 880
 881                                 //
 882                                 // There is no overflow checking on left shift
 883                                 //
 884                         case Binary.Operator.LeftShift:
 885                                 IntConstant ic = right.ToInt (loc);
 886                                 if (ic == null){
 887                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 888                                         return null;
 889                                 }
 890                                 int lshift_val = ic.Value;
 891
 892                                 IntConstant lic;
 893                                 if ((lic = left.ConvertToInt ()) != null)
 894                                         return new IntConstant (lic.Value << lshift_val);
 895
 896                                 UIntConstant luic;
 897                                 if ((luic = left.ConvertToUInt ()) != null)
 898                                         return new UIntConstant (luic.Value << lshift_val);
 899
 900                                 LongConstant llc;
 901                                 if ((llc = left.ConvertToLong ()) != null)
 902                                         return new LongConstant (llc.Value << lshift_val);
 903
 904                                 ULongConstant lulc;
 905                                 if ((lulc = left.ConvertToULong ()) != null)
 906                                         return new ULongConstant (lulc.Value << lshift_val);
 907
 908                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 909                                 break;
 910
 911                                 //
 912                                 // There is no overflow checking on right shift
 913                                 //
 914                         case Binary.Operator.RightShift:
 915                                 IntConstant sic = right.ToInt (loc);
 916                                 if (sic == null){
 917                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 918                                         return null;
 919                                 }
 920                                 int rshift_val = sic.Value;
 921
 922                                 IntConstant ric;
 923                                 if ((ric = left.ConvertToInt ()) != null)
 924                                         return new IntConstant (ric.Value >> rshift_val);
 925
 926                                 UIntConstant ruic;
 927                                 if ((ruic = left.ConvertToUInt ()) != null)
 928                                         return new UIntConstant (ruic.Value >> rshift_val);
 929
 930                                 LongConstant rlc;
 931                                 if ((rlc = left.ConvertToLong ()) != null)
 932                                         return new LongConstant (rlc.Value >> rshift_val);
 933
 934                                 ULongConstant rulc;
 935                                 if ((rulc = left.ConvertToULong ()) != null)
 936                                         return new ULongConstant (rulc.Value >> rshift_val);
 937
 938                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 939                                 break;
 940
 941                         case Binary.Operator.LogicalAnd:
 942                                 if (left is BoolConstant && right is BoolConstant){
 943                                         return new BoolConstant (
 944                                                 ((BoolConstant) left).Value &&
 945                                                 ((BoolConstant) right).Value);
 946                                 }
 947                                 break;
 948
 949                         case Binary.Operator.LogicalOr:
 950                                 if (left is BoolConstant && right is BoolConstant){
 951                                         return new BoolConstant (
 952                                                 ((BoolConstant) left).Value ||
 953                                                 ((BoolConstant) right).Value);
 954                                 }
 955                                 break;
 956
 957                         case Binary.Operator.Equality:
 958                                 if (left is BoolConstant && right is BoolConstant){
 959                                         return new BoolConstant (
 960                                                 ((BoolConstant) left).Value ==
 961                                                 ((BoolConstant) right).Value);
 962
 963                                 }
 964                                 if (left is StringConstant && right is StringConstant){
 965                                         return new BoolConstant (
 966                                                 ((StringConstant) left).Value ==
 967                                                 ((StringConstant) right).Value);
 968
 969                                 }
 970
 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.Inequality:
1000                                 if (left is BoolConstant && right is BoolConstant){
1001                                         return new BoolConstant (
1002                                                 ((BoolConstant) left).Value !=
1003                                                 ((BoolConstant) right).Value);
1004                                 }
1005                                 if (left is StringConstant && right is StringConstant){
1006                                         return new BoolConstant (
1007                                                 ((StringConstant) left).Value !=
1008                                                 ((StringConstant) right).Value);
1009
1010                                 }
1011                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1012                                 if (left == null || right == null)
1013                                         return null;
1014
1015                                 bool_res = false;
1016                                 if (left is DoubleConstant)
1017                                         bool_res = ((DoubleConstant) left).Value !=
1018                                                 ((DoubleConstant) right).Value;
1019                                 else if (left is FloatConstant)
1020                                         bool_res = ((FloatConstant) left).Value !=
1021                                                 ((FloatConstant) right).Value;
1022                                 else if (left is ULongConstant)
1023                                         bool_res = ((ULongConstant) left).Value !=
1024                                                 ((ULongConstant) right).Value;
1025                                 else if (left is LongConstant)
1026                                         bool_res = ((LongConstant) left).Value !=
1027                                                 ((LongConstant) right).Value;
1028                                 else if (left is UIntConstant)
1029                                         bool_res = ((UIntConstant) left).Value !=
1030                                                 ((UIntConstant) right).Value;
1031                                 else if (left is IntConstant)
1032                                         bool_res = ((IntConstant) left).Value !=
1033                                                 ((IntConstant) right).Value;
1034                                 else
1035                                         return null;
1036
1037                                 return new BoolConstant (bool_res);
1038
1039                         case Binary.Operator.LessThan:
1040                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1041                                 if (left == null || right == null)
1042                                         return null;
1043
1044                                 bool_res = false;
1045                                 if (left is DoubleConstant)
1046                                         bool_res = ((DoubleConstant) left).Value <
1047                                                 ((DoubleConstant) right).Value;
1048                                 else if (left is FloatConstant)
1049                                         bool_res = ((FloatConstant) left).Value <
1050                                                 ((FloatConstant) right).Value;
1051                                 else if (left is ULongConstant)
1052                                         bool_res = ((ULongConstant) left).Value <
1053                                                 ((ULongConstant) right).Value;
1054                                 else if (left is LongConstant)
1055                                         bool_res = ((LongConstant) left).Value <
1056                                                 ((LongConstant) right).Value;
1057                                 else if (left is UIntConstant)
1058                                         bool_res = ((UIntConstant) left).Value <
1059                                                 ((UIntConstant) right).Value;
1060                                 else if (left is IntConstant)
1061                                         bool_res = ((IntConstant) left).Value <
1062                                                 ((IntConstant) right).Value;
1063                                 else
1064                                         return null;
1065
1066                                 return new BoolConstant (bool_res);
1067
1068                         case Binary.Operator.GreaterThan:
1069                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1070                                 if (left == null || right == null)
1071                                         return null;
1072
1073                                 bool_res = false;
1074                                 if (left is DoubleConstant)
1075                                         bool_res = ((DoubleConstant) left).Value >
1076                                                 ((DoubleConstant) right).Value;
1077                                 else if (left is FloatConstant)
1078                                         bool_res = ((FloatConstant) left).Value >
1079                                                 ((FloatConstant) right).Value;
1080                                 else if (left is ULongConstant)
1081                                         bool_res = ((ULongConstant) left).Value >
1082                                                 ((ULongConstant) right).Value;
1083                                 else if (left is LongConstant)
1084                                         bool_res = ((LongConstant) left).Value >
1085                                                 ((LongConstant) right).Value;
1086                                 else if (left is UIntConstant)
1087                                         bool_res = ((UIntConstant) left).Value >
1088                                                 ((UIntConstant) right).Value;
1089                                 else if (left is IntConstant)
1090                                         bool_res = ((IntConstant) left).Value >
1091                                                 ((IntConstant) right).Value;
1092                                 else
1093                                         return null;
1094
1095                                 return new BoolConstant (bool_res);
1096
1097                         case Binary.Operator.GreaterThanOrEqual:
1098                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1099                                 if (left == null || right == null)
1100                                         return null;
1101
1102                                 bool_res = false;
1103                                 if (left is DoubleConstant)
1104                                         bool_res = ((DoubleConstant) left).Value >=
1105                                                 ((DoubleConstant) right).Value;
1106                                 else if (left is FloatConstant)
1107                                         bool_res = ((FloatConstant) left).Value >=
1108                                                 ((FloatConstant) right).Value;
1109                                 else if (left is ULongConstant)
1110                                         bool_res = ((ULongConstant) left).Value >=
1111                                                 ((ULongConstant) right).Value;
1112                                 else if (left is LongConstant)
1113                                         bool_res = ((LongConstant) left).Value >=
1114                                                 ((LongConstant) right).Value;
1115                                 else if (left is UIntConstant)
1116                                         bool_res = ((UIntConstant) left).Value >=
1117                                                 ((UIntConstant) right).Value;
1118                                 else if (left is IntConstant)
1119                                         bool_res = ((IntConstant) left).Value >=
1120                                                 ((IntConstant) right).Value;
1121                                 else
1122                                         return null;
1123
1124                                 return new BoolConstant (bool_res);
1125
1126                         case Binary.Operator.LessThanOrEqual:
1127                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1128                                 if (left == null || right == null)
1129                                         return null;
1130
1131                                 bool_res = false;
1132                                 if (left is DoubleConstant)
1133                                         bool_res = ((DoubleConstant) left).Value <=
1134                                                 ((DoubleConstant) right).Value;
1135                                 else if (left is FloatConstant)
1136                                         bool_res = ((FloatConstant) left).Value <=
1137                                                 ((FloatConstant) right).Value;
1138                                 else if (left is ULongConstant)
1139                                         bool_res = ((ULongConstant) left).Value <=
1140                                                 ((ULongConstant) right).Value;
1141                                 else if (left is LongConstant)
1142                                         bool_res = ((LongConstant) left).Value <=
1143                                                 ((LongConstant) right).Value;
1144                                 else if (left is UIntConstant)
1145                                         bool_res = ((UIntConstant) left).Value <=
1146                                                 ((UIntConstant) right).Value;
1147                                 else if (left is IntConstant)
1148                                         bool_res = ((IntConstant) left).Value <=
1149                                                 ((IntConstant) right).Value;
1150                                 else
1151                                         return null;
1152
1153                                 return new BoolConstant (bool_res);
1154                         }
1155
1156                         return null;
1157                 }
1158         }
1159 }