mcs/gmcs/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 #if WRONG
  63                                 Constant match, other;
  64 #endif
  65
  66                                 if (left is ULongConstant){
  67 #if WRONG
  68                                         other = right;
  69                                         match = left;
  70 #endif
  71                                         if (!(right is ULongConstant))
  72                                                 right = right.ToULong (loc);
  73                                 } else {
  74 #if WRONG
  75                                         other = left;
  76                                         match = right;
  77 #endif
  78                                         left = left.ToULong (loc);
  79                                 }
  80
  81 #if WRONG
  82                                 if (other is SByteConstant || other is ShortConstant ||
  83                                     other is IntConstant || other is LongConstant){
  84                                         Binary.Error_OperatorAmbiguous
  85                                                 (loc, oper, other.Type, match.Type);
  86                                         left = null;
  87                                         right = null;
  88                                 }
  89 #endif
  90                                 return;
  91                         } else if (left is LongConstant || right is LongConstant){
  92                                 //
  93                                 // If either operand is of type long, the other operand is converted
  94                                 // to type long.
  95                                 //
  96                                 if (!(left is LongConstant))
  97                                         left = left.ToLong (loc);
  98                                 else if (!(right is LongConstant))
  99                                         right = right.ToLong (loc);
 100                                 return;
 101                         } else if (left is UIntConstant || right is UIntConstant){
 102                                 //
 103                                 // If either operand is of type uint, and the other
 104                                 // operand is of type sbyte, short or int, the operands are
 105                                 // converted to type long.
 106                                 //
 107                                 Constant other;
 108                                 if (left is UIntConstant)
 109                                         other = right;
 110                                 else
 111                                         other = left;
 112
 113                                 // Nothing to do.
 114                                 if (other is UIntConstant)
 115                                         return;
 116
 117                                 IntConstant ic = other as IntConstant;
 118                                 if (ic != null){
 119                                         if (ic.Value >= 0){
 120                                                 if (left == other)
 121                                                         left = new UIntConstant ((uint) ic.Value);
 122                                                 else
 123                                                         right = new UIntConstant ((uint) ic.Value);
 124                                                 return;
 125                                         }
 126                                 }
 127
 128                                 if (other is SByteConstant || other is ShortConstant || ic != null){
 129                                         left = left.ToLong (loc);
 130                                         right = right.ToLong (loc);
 131                                 }
 132
 133                                 return;
 134                         } else if (left is EnumConstant || right is EnumConstant){
 135                                 //
 136                                 // If either operand is an enum constant, the other one must
 137                                 // be implicitly convertable to that enum's underlying type.
 138                                 //
 139                                 EnumConstant match;
 140                                 Constant other;
 141                                 if (left is EnumConstant){
 142                                         other = right;
 143                                         match = (EnumConstant) left;
 144                                 } else {
 145                                         other = left;
 146                                         match = (EnumConstant) right;
 147                                 }
 148
 149                                 bool need_check = (other is EnumConstant) ||
 150                                         ((oper != Binary.Operator.Addition) &&
 151                                          (oper != Binary.Operator.Subtraction));
 152
 153                                 if (need_check &&
 154                                     !Convert.ImplicitConversionExists (ec, match, other.Type)) {
 155                                         Convert.Error_CannotImplicitConversion (loc, match.Type, other.Type);
 156                                         left = null;
 157                                         right = null;
 158                                         return;
 159                                 }
 160
 161                                 if (left is EnumConstant)
 162                                         left = ((EnumConstant) left).Child;
 163                                 if (right is EnumConstant)
 164                                         right = ((EnumConstant) right).Child;
 165                                 return;
 166
 167                         } else {
 168                                 //
 169                                 // Force conversions to int32
 170                                 //
 171                                 if (!(left is IntConstant))
 172                                         left = left.ToInt (loc);
 173                                 if (!(right is IntConstant))
 174                                         right = right.ToInt (loc);
 175                         }
 176                         return;
 177                 }
 178
 179                 static void Error_CompileTimeOverflow (Location loc)
 180                 {
 181                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
 182                 }
 183
 184                 /// <summary>
 185                 ///   Constant expression folder for binary operations.
 186                 ///
 187                 ///   Returns null if the expression can not be folded.
 188                 /// </summary>
 189                 static public Expression BinaryFold (EmitContext ec, Binary.Operator oper,
 190                                                      Constant left, Constant right, Location loc)
 191                 {
 192                         Type lt = left.Type;
 193                         Type rt = right.Type;
 194                         Type result_type = null;
 195                         bool bool_res;
 196
 197                         //
 198                         // Enumerator folding
 199                         //
 200                         if (rt == lt && left is EnumConstant)
 201                                 result_type = lt;
 202
 203                         //
 204                         // During an enum evaluation, we need to unwrap enumerations
 205                         //
 206                         if (ec.InEnumContext){
 207                                 if (left is EnumConstant)
 208                                         left = ((EnumConstant) left).Child;
 209
 210                                 if (right is EnumConstant)
 211                                         right = ((EnumConstant) right).Child;
 212                         }
 213
 214                         Type wrap_as;
 215                         Constant result = null;
 216                         switch (oper){
 217                         case Binary.Operator.BitwiseOr:
 218                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 219                                 if (left == null || right == null)
 220                                         return null;
 221
 222                                 if (left is IntConstant){
 223                                         IntConstant v;
 224                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 225
 226                                         v = new IntConstant (res);
 227                                         if (result_type == null)
 228                                                 return v;
 229                                         else
 230                                                 return new EnumConstant (v, result_type);
 231                                 } else if (left is UIntConstant){
 232                                         UIntConstant v;
 233                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 234
 235                                         v = new UIntConstant (res);
 236                                         if (result_type == null)
 237                                                 return v;
 238                                         else
 239                                                 return new EnumConstant (v, result_type);
 240                                 } else if (left is LongConstant){
 241                                         LongConstant v;
 242                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 243
 244                                         v = new LongConstant (res);
 245                                         if (result_type == null)
 246                                                 return v;
 247                                         else
 248                                                 return new EnumConstant (v, result_type);
 249                                 } else if (left is ULongConstant){
 250                                         ULongConstant v;
 251                                         ulong res = ((ULongConstant)left).Value |
 252                                                 ((ULongConstant)right).Value;
 253
 254                                         v = new ULongConstant (res);
 255                                         if (result_type == null)
 256                                                 return v;
 257                                         else
 258                                                 return new EnumConstant (v, result_type);
 259                                 } else if (left is UShortConstant){
 260                                         UShortConstant v;
 261                                         ushort res = (ushort) (((UShortConstant)left).Value |
 262                                                                ((UShortConstant)right).Value);
 263
 264                                         v = new UShortConstant (res);
 265                                         if (result_type == null)
 266                                                 return v;
 267                                         else
 268                                                 return new EnumConstant (v, result_type);
 269                                 } else if (left is ShortConstant){
 270                                         ShortConstant v;
 271                                         short res = (short) (((ShortConstant)left).Value |
 272                                                              ((ShortConstant)right).Value);
 273
 274                                         v = new ShortConstant (res);
 275                                         if (result_type == null)
 276                                                 return v;
 277                                         else
 278                                                 return new EnumConstant (v, result_type);
 279                                 }
 280                                 break;
 281
 282                         case Binary.Operator.BitwiseAnd:
 283                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 284                                 if (left == null || right == null)
 285                                         return null;
 286
 287                                 if (left is IntConstant){
 288                                         IntConstant v;
 289                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 290
 291                                         v = new IntConstant (res);
 292                                         if (result_type == null)
 293                                                 return v;
 294                                         else
 295                                                 return new EnumConstant (v, result_type);
 296                                 } else if (left is UIntConstant){
 297                                         UIntConstant v;
 298                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 299
 300                                         v = new UIntConstant (res);
 301                                         if (result_type == null)
 302                                                 return v;
 303                                         else
 304                                                 return new EnumConstant (v, result_type);
 305                                 } else if (left is LongConstant){
 306                                         LongConstant v;
 307                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 308
 309                                         v = new LongConstant (res);
 310                                         if (result_type == null)
 311                                                 return v;
 312                                         else
 313                                                 return new EnumConstant (v, result_type);
 314                                 } else if (left is ULongConstant){
 315                                         ULongConstant v;
 316                                         ulong res = ((ULongConstant)left).Value &
 317                                                 ((ULongConstant)right).Value;
 318
 319                                         v = new ULongConstant (res);
 320                                         if (result_type == null)
 321                                                 return v;
 322                                         else
 323                                                 return new EnumConstant (v, result_type);
 324                                 } else if (left is UShortConstant){
 325                                         UShortConstant v;
 326                                         ushort res = (ushort) (((UShortConstant)left).Value &
 327                                                                ((UShortConstant)right).Value);
 328
 329                                         v = new UShortConstant (res);
 330                                         if (result_type == null)
 331                                                 return v;
 332                                         else
 333                                                 return new EnumConstant (v, result_type);
 334                                 } else if (left is ShortConstant){
 335                                         ShortConstant v;
 336                                         short res = (short) (((ShortConstant)left).Value &
 337                                                              ((ShortConstant)right).Value);
 338
 339                                         v = new ShortConstant (res);
 340                                         if (result_type == null)
 341                                                 return v;
 342                                         else
 343                                                 return new EnumConstant (v, result_type);
 344                                 }
 345                                 break;
 346
 347                         case Binary.Operator.ExclusiveOr:
 348                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 349                                 if (left == null || right == null)
 350                                         return null;
 351
 352                                 if (left is IntConstant){
 353                                         IntConstant v;
 354                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 355
 356                                         v = new IntConstant (res);
 357                                         if (result_type == null)
 358                                                 return v;
 359                                         else
 360                                                 return new EnumConstant (v, result_type);
 361                                 } else if (left is UIntConstant){
 362                                         UIntConstant v;
 363                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 364
 365                                         v = new UIntConstant (res);
 366                                         if (result_type == null)
 367                                                 return v;
 368                                         else
 369                                                 return new EnumConstant (v, result_type);
 370                                 } else if (left is LongConstant){
 371                                         LongConstant v;
 372                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 373
 374                                         v = new LongConstant (res);
 375                                         if (result_type == null)
 376                                                 return v;
 377                                         else
 378                                                 return new EnumConstant (v, result_type);
 379                                 } else if (left is ULongConstant){
 380                                         ULongConstant v;
 381                                         ulong res = ((ULongConstant)left).Value ^
 382                                                 ((ULongConstant)right).Value;
 383
 384                                         v = new ULongConstant (res);
 385                                         if (result_type == null)
 386                                                 return v;
 387                                         else
 388                                                 return new EnumConstant (v, result_type);
 389                                 } else if (left is UShortConstant){
 390                                         UShortConstant v;
 391                                         ushort res = (ushort) (((UShortConstant)left).Value ^
 392                                                                ((UShortConstant)right).Value);
 393
 394                                         v = new UShortConstant (res);
 395                                         if (result_type == null)
 396                                                 return v;
 397                                         else
 398                                                 return new EnumConstant (v, result_type);
 399                                 } else if (left is ShortConstant){
 400                                         ShortConstant v;
 401                                         short res = (short)(((ShortConstant)left).Value ^
 402                                                             ((ShortConstant)right).Value);
 403
 404                                         v = new ShortConstant (res);
 405                                         if (result_type == null)
 406                                                 return v;
 407                                         else
 408                                                 return new EnumConstant (v, result_type);
 409                                 }
 410                                 break;
 411
 412                         case Binary.Operator.Addition:
 413                                 bool left_is_string = left is StringConstant;
 414                                 bool right_is_string = right is StringConstant;
 415
 416                                 //
 417                                 // If both sides are strings, then concatenate, if
 418                                 // one is a string, and the other is not, then defer
 419                                 // to runtime concatenation
 420                                 //
 421                                 wrap_as = null;
 422                                 if (left_is_string || right_is_string){
 423                                         if (left_is_string && right_is_string)
 424                                                 return new StringConstant (
 425                                                         ((StringConstant) left).Value +
 426                                                         ((StringConstant) right).Value);
 427
 428                                         return null;
 429                                 }
 430
 431                                 //
 432                                 // handle "E operator + (E x, U y)"
 433                                 // handle "E operator + (Y y, E x)"
 434                                 //
 435                                 // note that E operator + (E x, E y) is invalid
 436                                 //
 437                                 if (left is EnumConstant){
 438                                         if (right is EnumConstant){
 439                                                 return null;
 440                                         }
 441                                         if (((EnumConstant) left).Child.Type != right.Type)
 442                                                 return null;
 443
 444                                         wrap_as = left.Type;
 445                                 } else if (right is EnumConstant){
 446                                         if (((EnumConstant) right).Child.Type != left.Type)
 447                                                 return null;
 448                                         wrap_as = right.Type;
 449                                 }
 450
 451                                 result = null;
 452                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 453                                 if (left == null || right == null)
 454                                         return null;
 455
 456                                 try {
 457                                         if (left is DoubleConstant){
 458                                                 double res;
 459
 460                                                 if (ec.ConstantCheckState)
 461                                                         res = checked (((DoubleConstant) left).Value +
 462                                                                        ((DoubleConstant) right).Value);
 463                                                 else
 464                                                         res = unchecked (((DoubleConstant) left).Value +
 465                                                                          ((DoubleConstant) right).Value);
 466
 467                                                 result = new DoubleConstant (res);
 468                                         } else if (left is FloatConstant){
 469                                                 float res;
 470
 471                                                 if (ec.ConstantCheckState)
 472                                                         res = checked (((FloatConstant) left).Value +
 473                                                                        ((FloatConstant) right).Value);
 474                                                 else
 475                                                         res = unchecked (((FloatConstant) left).Value +
 476                                                                          ((FloatConstant) right).Value);
 477
 478                                                 result = new FloatConstant (res);
 479                                         } else if (left is ULongConstant){
 480                                                 ulong res;
 481
 482                                                 if (ec.ConstantCheckState)
 483                                                         res = checked (((ULongConstant) left).Value +
 484                                                                        ((ULongConstant) right).Value);
 485                                                 else
 486                                                         res = unchecked (((ULongConstant) left).Value +
 487                                                                          ((ULongConstant) right).Value);
 488
 489                                                 result = new ULongConstant (res);
 490                                         } else if (left is LongConstant){
 491                                                 long res;
 492
 493                                                 if (ec.ConstantCheckState)
 494                                                         res = checked (((LongConstant) left).Value +
 495                                                                        ((LongConstant) right).Value);
 496                                                 else
 497                                                         res = unchecked (((LongConstant) left).Value +
 498                                                                          ((LongConstant) right).Value);
 499
 500                                                 result = new LongConstant (res);
 501                                         } else if (left is UIntConstant){
 502                                                 uint res;
 503
 504                                                 if (ec.ConstantCheckState)
 505                                                         res = checked (((UIntConstant) left).Value +
 506                                                                        ((UIntConstant) right).Value);
 507                                                 else
 508                                                         res = unchecked (((UIntConstant) left).Value +
 509                                                                          ((UIntConstant) right).Value);
 510
 511                                                 result = new UIntConstant (res);
 512                                         } else if (left is IntConstant){
 513                                                 int res;
 514
 515                                                 if (ec.ConstantCheckState)
 516                                                         res = checked (((IntConstant) left).Value +
 517                                                                        ((IntConstant) right).Value);
 518                                                 else
 519                                                         res = unchecked (((IntConstant) left).Value +
 520                                                                          ((IntConstant) right).Value);
 521
 522                                                 result = new IntConstant (res);
 523                                         } else {
 524                                                 throw new Exception ( "Unexepected input: " + left);
 525                                         }
 526                                 } catch (OverflowException){
 527                                         Error_CompileTimeOverflow (loc);
 528                                 }
 529
 530                                 if (wrap_as != null)
 531                                         return new EnumConstant (result, wrap_as);
 532                                 else
 533                                         return result;
 534
 535                         case Binary.Operator.Subtraction:
 536                                 //
 537                                 // handle "E operator - (E x, U y)"
 538                                 // handle "E operator - (Y y, E x)"
 539                                 // handle "U operator - (E x, E y)"
 540                                 //
 541                                 wrap_as = null;
 542                                 if (left is EnumConstant){
 543                                         if (right is EnumConstant){
 544                                                 if (left.Type == right.Type)
 545                                                         wrap_as = TypeManager.EnumToUnderlying (left.Type);
 546                                                 else
 547                                                         return null;
 548                                         }
 549                                         if (((EnumConstant) left).Child.Type != right.Type)
 550                                                 return null;
 551
 552                                         wrap_as = left.Type;
 553                                 } else if (right is EnumConstant){
 554                                         if (((EnumConstant) right).Child.Type != left.Type)
 555                                                 return null;
 556                                         wrap_as = right.Type;
 557                                 }
 558
 559                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 560                                 if (left == null || right == null)
 561                                         return null;
 562
 563                                 try {
 564                                         if (left is DoubleConstant){
 565                                                 double res;
 566
 567                                                 if (ec.ConstantCheckState)
 568                                                         res = checked (((DoubleConstant) left).Value -
 569                                                                        ((DoubleConstant) right).Value);
 570                                                 else
 571                                                         res = unchecked (((DoubleConstant) left).Value -
 572                                                                          ((DoubleConstant) right).Value);
 573
 574                                                 result = new DoubleConstant (res);
 575                                         } else if (left is FloatConstant){
 576                                                 float res;
 577
 578                                                 if (ec.ConstantCheckState)
 579                                                         res = checked (((FloatConstant) left).Value -
 580                                                                        ((FloatConstant) right).Value);
 581                                                 else
 582                                                         res = unchecked (((FloatConstant) left).Value -
 583                                                                          ((FloatConstant) right).Value);
 584
 585                                                 result = new FloatConstant (res);
 586                                         } else if (left is ULongConstant){
 587                                                 ulong res;
 588
 589                                                 if (ec.ConstantCheckState)
 590                                                         res = checked (((ULongConstant) left).Value -
 591                                                                        ((ULongConstant) right).Value);
 592                                                 else
 593                                                         res = unchecked (((ULongConstant) left).Value -
 594                                                                          ((ULongConstant) right).Value);
 595
 596                                                 result = new ULongConstant (res);
 597                                         } else if (left is LongConstant){
 598                                                 long res;
 599
 600                                                 if (ec.ConstantCheckState)
 601                                                         res = checked (((LongConstant) left).Value -
 602                                                                        ((LongConstant) right).Value);
 603                                                 else
 604                                                         res = unchecked (((LongConstant) left).Value -
 605                                                                          ((LongConstant) right).Value);
 606
 607                                                 result = new LongConstant (res);
 608                                         } else if (left is UIntConstant){
 609                                                 uint res;
 610
 611                                                 if (ec.ConstantCheckState)
 612                                                         res = checked (((UIntConstant) left).Value -
 613                                                                        ((UIntConstant) right).Value);
 614                                                 else
 615                                                         res = unchecked (((UIntConstant) left).Value -
 616                                                                          ((UIntConstant) right).Value);
 617
 618                                                 result = new UIntConstant (res);
 619                                         } else if (left is IntConstant){
 620                                                 int res;
 621
 622                                                 if (ec.ConstantCheckState)
 623                                                         res = checked (((IntConstant) left).Value -
 624                                                                        ((IntConstant) right).Value);
 625                                                 else
 626                                                         res = unchecked (((IntConstant) left).Value -
 627                                                                          ((IntConstant) right).Value);
 628
 629                                                 result = new IntConstant (res);
 630                                         } else {
 631                                                 throw new Exception ( "Unexepected input: " + left);
 632                                         }
 633                                 } catch (OverflowException){
 634                                         Error_CompileTimeOverflow (loc);
 635                                 }
 636                                 if (wrap_as != null)
 637                                         return new EnumConstant (result, wrap_as);
 638                                 else
 639                                         return result;
 640
 641                         case Binary.Operator.Multiply:
 642                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 643                                 if (left == null || right == null)
 644                                         return null;
 645
 646                                 try {
 647                                         if (left is DoubleConstant){
 648                                                 double res;
 649
 650                                                 if (ec.ConstantCheckState)
 651                                                         res = checked (((DoubleConstant) left).Value *
 652                                                                        ((DoubleConstant) right).Value);
 653                                                 else
 654                                                         res = unchecked (((DoubleConstant) left).Value *
 655                                                                          ((DoubleConstant) right).Value);
 656
 657                                                 return new DoubleConstant (res);
 658                                         } else if (left is FloatConstant){
 659                                                 float res;
 660
 661                                                 if (ec.ConstantCheckState)
 662                                                         res = checked (((FloatConstant) left).Value *
 663                                                                        ((FloatConstant) right).Value);
 664                                                 else
 665                                                         res = unchecked (((FloatConstant) left).Value *
 666                                                                          ((FloatConstant) right).Value);
 667
 668                                                 return new FloatConstant (res);
 669                                         } else if (left is ULongConstant){
 670                                                 ulong res;
 671
 672                                                 if (ec.ConstantCheckState)
 673                                                         res = checked (((ULongConstant) left).Value *
 674                                                                        ((ULongConstant) right).Value);
 675                                                 else
 676                                                         res = unchecked (((ULongConstant) left).Value *
 677                                                                          ((ULongConstant) right).Value);
 678
 679                                                 return new ULongConstant (res);
 680                                         } else if (left is LongConstant){
 681                                                 long res;
 682
 683                                                 if (ec.ConstantCheckState)
 684                                                         res = checked (((LongConstant) left).Value *
 685                                                                        ((LongConstant) right).Value);
 686                                                 else
 687                                                         res = unchecked (((LongConstant) left).Value *
 688                                                                          ((LongConstant) right).Value);
 689
 690                                                 return new LongConstant (res);
 691                                         } else if (left is UIntConstant){
 692                                                 uint res;
 693
 694                                                 if (ec.ConstantCheckState)
 695                                                         res = checked (((UIntConstant) left).Value *
 696                                                                        ((UIntConstant) right).Value);
 697                                                 else
 698                                                         res = unchecked (((UIntConstant) left).Value *
 699                                                                          ((UIntConstant) right).Value);
 700
 701                                                 return new UIntConstant (res);
 702                                         } else if (left is IntConstant){
 703                                                 int res;
 704
 705                                                 if (ec.ConstantCheckState)
 706                                                         res = checked (((IntConstant) left).Value *
 707                                                                        ((IntConstant) right).Value);
 708                                                 else
 709                                                         res = unchecked (((IntConstant) left).Value *
 710                                                                          ((IntConstant) right).Value);
 711
 712                                                 return new IntConstant (res);
 713                                         } else {
 714                                                 throw new Exception ( "Unexepected input: " + left);
 715                                         }
 716                                 } catch (OverflowException){
 717                                         Error_CompileTimeOverflow (loc);
 718                                 }
 719                                 break;
 720
 721                         case Binary.Operator.Division:
 722                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 723                                 if (left == null || right == null)
 724                                         return null;
 725
 726                                 try {
 727                                         if (left is DoubleConstant){
 728                                                 double res;
 729
 730                                                 if (ec.ConstantCheckState)
 731                                                         res = checked (((DoubleConstant) left).Value /
 732                                                                        ((DoubleConstant) right).Value);
 733                                                 else
 734                                                         res = unchecked (((DoubleConstant) left).Value /
 735                                                                          ((DoubleConstant) right).Value);
 736
 737                                                 return new DoubleConstant (res);
 738                                         } else if (left is FloatConstant){
 739                                                 float res;
 740
 741                                                 if (ec.ConstantCheckState)
 742                                                         res = checked (((FloatConstant) left).Value /
 743                                                                        ((FloatConstant) right).Value);
 744                                                 else
 745                                                         res = unchecked (((FloatConstant) left).Value /
 746                                                                          ((FloatConstant) right).Value);
 747
 748                                                 return new FloatConstant (res);
 749                                         } else if (left is ULongConstant){
 750                                                 ulong res;
 751
 752                                                 if (ec.ConstantCheckState)
 753                                                         res = checked (((ULongConstant) left).Value /
 754                                                                        ((ULongConstant) right).Value);
 755                                                 else
 756                                                         res = unchecked (((ULongConstant) left).Value /
 757                                                                          ((ULongConstant) right).Value);
 758
 759                                                 return new ULongConstant (res);
 760                                         } else if (left is LongConstant){
 761                                                 long res;
 762
 763                                                 if (ec.ConstantCheckState)
 764                                                         res = checked (((LongConstant) left).Value /
 765                                                                        ((LongConstant) right).Value);
 766                                                 else
 767                                                         res = unchecked (((LongConstant) left).Value /
 768                                                                          ((LongConstant) right).Value);
 769
 770                                                 return new LongConstant (res);
 771                                         } else if (left is UIntConstant){
 772                                                 uint res;
 773
 774                                                 if (ec.ConstantCheckState)
 775                                                         res = checked (((UIntConstant) left).Value /
 776                                                                        ((UIntConstant) right).Value);
 777                                                 else
 778                                                         res = unchecked (((UIntConstant) left).Value /
 779                                                                          ((UIntConstant) right).Value);
 780
 781                                                 return new UIntConstant (res);
 782                                         } else if (left is IntConstant){
 783                                                 int res;
 784
 785                                                 if (ec.ConstantCheckState)
 786                                                         res = checked (((IntConstant) left).Value /
 787                                                                        ((IntConstant) right).Value);
 788                                                 else
 789                                                         res = unchecked (((IntConstant) left).Value /
 790                                                                          ((IntConstant) right).Value);
 791
 792                                                 return new IntConstant (res);
 793                                         } else {
 794                                                 throw new Exception ( "Unexepected input: " + left);
 795                                         }
 796                                 } catch (OverflowException){
 797                                         Error_CompileTimeOverflow (loc);
 798
 799                                 } catch (DivideByZeroException) {
 800                                         Report.Error (020, loc, "Division by constant zero");
 801                                 }
 802
 803                                 break;
 804
 805                         case Binary.Operator.Modulus:
 806                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 807                                 if (left == null || right == null)
 808                                         return null;
 809
 810                                 try {
 811                                         if (left is DoubleConstant){
 812                                                 double res;
 813
 814                                                 if (ec.ConstantCheckState)
 815                                                         res = checked (((DoubleConstant) left).Value %
 816                                                                        ((DoubleConstant) right).Value);
 817                                                 else
 818                                                         res = unchecked (((DoubleConstant) left).Value %
 819                                                                          ((DoubleConstant) right).Value);
 820
 821                                                 return new DoubleConstant (res);
 822                                         } else if (left is FloatConstant){
 823                                                 float res;
 824
 825                                                 if (ec.ConstantCheckState)
 826                                                         res = checked (((FloatConstant) left).Value %
 827                                                                        ((FloatConstant) right).Value);
 828                                                 else
 829                                                         res = unchecked (((FloatConstant) left).Value %
 830                                                                          ((FloatConstant) right).Value);
 831
 832                                                 return new FloatConstant (res);
 833                                         } else if (left is ULongConstant){
 834                                                 ulong res;
 835
 836                                                 if (ec.ConstantCheckState)
 837                                                         res = checked (((ULongConstant) left).Value %
 838                                                                        ((ULongConstant) right).Value);
 839                                                 else
 840                                                         res = unchecked (((ULongConstant) left).Value %
 841                                                                          ((ULongConstant) right).Value);
 842
 843                                                 return new ULongConstant (res);
 844                                         } else if (left is LongConstant){
 845                                                 long res;
 846
 847                                                 if (ec.ConstantCheckState)
 848                                                         res = checked (((LongConstant) left).Value %
 849                                                                        ((LongConstant) right).Value);
 850                                                 else
 851                                                         res = unchecked (((LongConstant) left).Value %
 852                                                                          ((LongConstant) right).Value);
 853
 854                                                 return new LongConstant (res);
 855                                         } else if (left is UIntConstant){
 856                                                 uint res;
 857
 858                                                 if (ec.ConstantCheckState)
 859                                                         res = checked (((UIntConstant) left).Value %
 860                                                                        ((UIntConstant) right).Value);
 861                                                 else
 862                                                         res = unchecked (((UIntConstant) left).Value %
 863                                                                          ((UIntConstant) right).Value);
 864
 865                                                 return new UIntConstant (res);
 866                                         } else if (left is IntConstant){
 867                                                 int res;
 868
 869                                                 if (ec.ConstantCheckState)
 870                                                         res = checked (((IntConstant) left).Value %
 871                                                                        ((IntConstant) right).Value);
 872                                                 else
 873                                                         res = unchecked (((IntConstant) left).Value %
 874                                                                          ((IntConstant) right).Value);
 875
 876                                                 return new IntConstant (res);
 877                                         } else {
 878                                                 throw new Exception ( "Unexepected input: " + left);
 879                                         }
 880                                 } catch (DivideByZeroException){
 881                                         Report.Error (020, loc, "Division by constant zero");
 882                                 } catch (OverflowException){
 883                                         Error_CompileTimeOverflow (loc);
 884                                 }
 885                                 break;
 886
 887                                 //
 888                                 // There is no overflow checking on left shift
 889                                 //
 890                         case Binary.Operator.LeftShift:
 891                                 IntConstant ic = right.ToInt (loc);
 892                                 if (ic == null){
 893                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 894                                         return null;
 895                                 }
 896                                 int lshift_val = ic.Value;
 897
 898                                 IntConstant lic;
 899                                 if ((lic = left.ConvertToInt ()) != null)
 900                                         return new IntConstant (lic.Value << lshift_val);
 901
 902                                 UIntConstant luic;
 903                                 if ((luic = left.ConvertToUInt ()) != null)
 904                                         return new UIntConstant (luic.Value << lshift_val);
 905
 906                                 LongConstant llc;
 907                                 if ((llc = left.ConvertToLong ()) != null)
 908                                         return new LongConstant (llc.Value << lshift_val);
 909
 910                                 ULongConstant lulc;
 911                                 if ((lulc = left.ConvertToULong ()) != null)
 912                                         return new ULongConstant (lulc.Value << lshift_val);
 913
 914                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 915                                 break;
 916
 917                                 //
 918                                 // There is no overflow checking on right shift
 919                                 //
 920                         case Binary.Operator.RightShift:
 921                                 IntConstant sic = right.ToInt (loc);
 922                                 if (sic == null){
 923                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 924                                         return null;
 925                                 }
 926                                 int rshift_val = sic.Value;
 927
 928                                 IntConstant ric;
 929                                 if ((ric = left.ConvertToInt ()) != null)
 930                                         return new IntConstant (ric.Value >> rshift_val);
 931
 932                                 UIntConstant ruic;
 933                                 if ((ruic = left.ConvertToUInt ()) != null)
 934                                         return new UIntConstant (ruic.Value >> rshift_val);
 935
 936                                 LongConstant rlc;
 937                                 if ((rlc = left.ConvertToLong ()) != null)
 938                                         return new LongConstant (rlc.Value >> rshift_val);
 939
 940                                 ULongConstant rulc;
 941                                 if ((rulc = left.ConvertToULong ()) != null)
 942                                         return new ULongConstant (rulc.Value >> rshift_val);
 943
 944                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 945                                 break;
 946
 947                         case Binary.Operator.LogicalAnd:
 948                                 if (left is BoolConstant && right is BoolConstant){
 949                                         return new BoolConstant (
 950                                                 ((BoolConstant) left).Value &&
 951                                                 ((BoolConstant) right).Value);
 952                                 }
 953                                 break;
 954
 955                         case Binary.Operator.LogicalOr:
 956                                 if (left is BoolConstant && right is BoolConstant){
 957                                         return new BoolConstant (
 958                                                 ((BoolConstant) left).Value ||
 959                                                 ((BoolConstant) right).Value);
 960                                 }
 961                                 break;
 962
 963                         case Binary.Operator.Equality:
 964                                 if (left is BoolConstant && right is BoolConstant){
 965                                         return new BoolConstant (
 966                                                 ((BoolConstant) left).Value ==
 967                                                 ((BoolConstant) right).Value);
 968
 969                                 }
 970                                 if (left is NullLiteral){
 971                                         if (right is NullLiteral)
 972                                                 return new BoolConstant (true);
 973                                         else if (right is StringConstant)
 974                                                 return new BoolConstant (
 975                                                         ((StringConstant) right).Value == null);
 976                                 } else if (right is NullLiteral){
 977                                         if (left is NullLiteral)
 978                                                 return new BoolConstant (true);
 979                                         else if (left is StringConstant)
 980                                                 return new BoolConstant (
 981                                                         ((StringConstant) left).Value == null);
 982                                 }
 983                                 if (left is StringConstant && right is StringConstant){
 984                                         return new BoolConstant (
 985                                                 ((StringConstant) left).Value ==
 986                                                 ((StringConstant) right).Value);
 987
 988                                 }
 989
 990                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
 991                                 if (left == null || right == null)
 992                                         return null;
 993
 994                                 bool_res = false;
 995                                 if (left is DoubleConstant)
 996                                         bool_res = ((DoubleConstant) left).Value ==
 997                                                 ((DoubleConstant) right).Value;
 998                                 else if (left is FloatConstant)
 999                                         bool_res = ((FloatConstant) left).Value ==
1000                                                 ((FloatConstant) right).Value;
1001                                 else if (left is ULongConstant)
1002                                         bool_res = ((ULongConstant) left).Value ==
1003                                                 ((ULongConstant) right).Value;
1004                                 else if (left is LongConstant)
1005                                         bool_res = ((LongConstant) left).Value ==
1006                                                 ((LongConstant) right).Value;
1007                                 else if (left is UIntConstant)
1008                                         bool_res = ((UIntConstant) left).Value ==
1009                                                 ((UIntConstant) right).Value;
1010                                 else if (left is IntConstant)
1011                                         bool_res = ((IntConstant) left).Value ==
1012                                                 ((IntConstant) right).Value;
1013                                 else
1014                                         return null;
1015
1016                                 return new BoolConstant (bool_res);
1017
1018                         case Binary.Operator.Inequality:
1019                                 if (left is BoolConstant && right is BoolConstant){
1020                                         return new BoolConstant (
1021                                                 ((BoolConstant) left).Value !=
1022                                                 ((BoolConstant) right).Value);
1023                                 }
1024                                 if (left is NullLiteral){
1025                                         if (right is NullLiteral)
1026                                                 return new BoolConstant (false);
1027                                         else if (right is StringConstant)
1028                                                 return new BoolConstant (
1029                                                         ((StringConstant) right).Value != null);
1030                                 } else if (right is NullLiteral){
1031                                         if (left is NullLiteral)
1032                                                 return new BoolConstant (false);
1033                                         else if (left is StringConstant)
1034                                                 return new BoolConstant (
1035                                                         ((StringConstant) left).Value != null);
1036                                 }
1037                                 if (left is StringConstant && right is StringConstant){
1038                                         return new BoolConstant (
1039                                                 ((StringConstant) left).Value !=
1040                                                 ((StringConstant) right).Value);
1041
1042                                 }
1043                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1044                                 if (left == null || right == null)
1045                                         return null;
1046
1047                                 bool_res = false;
1048                                 if (left is DoubleConstant)
1049                                         bool_res = ((DoubleConstant) left).Value !=
1050                                                 ((DoubleConstant) right).Value;
1051                                 else if (left is FloatConstant)
1052                                         bool_res = ((FloatConstant) left).Value !=
1053                                                 ((FloatConstant) right).Value;
1054                                 else if (left is ULongConstant)
1055                                         bool_res = ((ULongConstant) left).Value !=
1056                                                 ((ULongConstant) right).Value;
1057                                 else if (left is LongConstant)
1058                                         bool_res = ((LongConstant) left).Value !=
1059                                                 ((LongConstant) right).Value;
1060                                 else if (left is UIntConstant)
1061                                         bool_res = ((UIntConstant) left).Value !=
1062                                                 ((UIntConstant) right).Value;
1063                                 else if (left is IntConstant)
1064                                         bool_res = ((IntConstant) left).Value !=
1065                                                 ((IntConstant) right).Value;
1066                                 else
1067                                         return null;
1068
1069                                 return new BoolConstant (bool_res);
1070
1071                         case Binary.Operator.LessThan:
1072                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1073                                 if (left == null || right == null)
1074                                         return null;
1075
1076                                 bool_res = false;
1077                                 if (left is DoubleConstant)
1078                                         bool_res = ((DoubleConstant) left).Value <
1079                                                 ((DoubleConstant) right).Value;
1080                                 else if (left is FloatConstant)
1081                                         bool_res = ((FloatConstant) left).Value <
1082                                                 ((FloatConstant) right).Value;
1083                                 else if (left is ULongConstant)
1084                                         bool_res = ((ULongConstant) left).Value <
1085                                                 ((ULongConstant) right).Value;
1086                                 else if (left is LongConstant)
1087                                         bool_res = ((LongConstant) left).Value <
1088                                                 ((LongConstant) right).Value;
1089                                 else if (left is UIntConstant)
1090                                         bool_res = ((UIntConstant) left).Value <
1091                                                 ((UIntConstant) right).Value;
1092                                 else if (left is IntConstant)
1093                                         bool_res = ((IntConstant) left).Value <
1094                                                 ((IntConstant) right).Value;
1095                                 else
1096                                         return null;
1097
1098                                 return new BoolConstant (bool_res);
1099
1100                         case Binary.Operator.GreaterThan:
1101                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1102                                 if (left == null || right == null)
1103                                         return null;
1104
1105                                 bool_res = false;
1106                                 if (left is DoubleConstant)
1107                                         bool_res = ((DoubleConstant) left).Value >
1108                                                 ((DoubleConstant) right).Value;
1109                                 else if (left is FloatConstant)
1110                                         bool_res = ((FloatConstant) left).Value >
1111                                                 ((FloatConstant) right).Value;
1112                                 else if (left is ULongConstant)
1113                                         bool_res = ((ULongConstant) left).Value >
1114                                                 ((ULongConstant) right).Value;
1115                                 else if (left is LongConstant)
1116                                         bool_res = ((LongConstant) left).Value >
1117                                                 ((LongConstant) right).Value;
1118                                 else if (left is UIntConstant)
1119                                         bool_res = ((UIntConstant) left).Value >
1120                                                 ((UIntConstant) right).Value;
1121                                 else if (left is IntConstant)
1122                                         bool_res = ((IntConstant) left).Value >
1123                                                 ((IntConstant) right).Value;
1124                                 else
1125                                         return null;
1126
1127                                 return new BoolConstant (bool_res);
1128
1129                         case Binary.Operator.GreaterThanOrEqual:
1130                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1131                                 if (left == null || right == null)
1132                                         return null;
1133
1134                                 bool_res = false;
1135                                 if (left is DoubleConstant)
1136                                         bool_res = ((DoubleConstant) left).Value >=
1137                                                 ((DoubleConstant) right).Value;
1138                                 else if (left is FloatConstant)
1139                                         bool_res = ((FloatConstant) left).Value >=
1140                                                 ((FloatConstant) right).Value;
1141                                 else if (left is ULongConstant)
1142                                         bool_res = ((ULongConstant) left).Value >=
1143                                                 ((ULongConstant) right).Value;
1144                                 else if (left is LongConstant)
1145                                         bool_res = ((LongConstant) left).Value >=
1146                                                 ((LongConstant) right).Value;
1147                                 else if (left is UIntConstant)
1148                                         bool_res = ((UIntConstant) left).Value >=
1149                                                 ((UIntConstant) right).Value;
1150                                 else if (left is IntConstant)
1151                                         bool_res = ((IntConstant) left).Value >=
1152                                                 ((IntConstant) right).Value;
1153                                 else
1154                                         return null;
1155
1156                                 return new BoolConstant (bool_res);
1157
1158                         case Binary.Operator.LessThanOrEqual:
1159                                 DoConstantNumericPromotions (ec, oper, ref left, ref right, loc);
1160                                 if (left == null || right == null)
1161                                         return null;
1162
1163                                 bool_res = false;
1164                                 if (left is DoubleConstant)
1165                                         bool_res = ((DoubleConstant) left).Value <=
1166                                                 ((DoubleConstant) right).Value;
1167                                 else if (left is FloatConstant)
1168                                         bool_res = ((FloatConstant) left).Value <=
1169                                                 ((FloatConstant) right).Value;
1170                                 else if (left is ULongConstant)
1171                                         bool_res = ((ULongConstant) left).Value <=
1172                                                 ((ULongConstant) right).Value;
1173                                 else if (left is LongConstant)
1174                                         bool_res = ((LongConstant) left).Value <=
1175                                                 ((LongConstant) right).Value;
1176                                 else if (left is UIntConstant)
1177                                         bool_res = ((UIntConstant) left).Value <=
1178                                                 ((UIntConstant) right).Value;
1179                                 else if (left is IntConstant)
1180                                         bool_res = ((IntConstant) left).Value <=
1181                                                 ((IntConstant) right).Value;
1182                                 else
1183                                         return null;
1184
1185                                 return new BoolConstant (bool_res);
1186                         }
1187
1188                         return null;
1189                 }
1190         }
1191 }