mcs/mcs/cfold.cs

   1 //
   2 // cfold.cs: Constant Folding
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // (C) 2002, 2003 Ximian, Inc.
   9 //
  10
  11 using System;
  12
  13 namespace Mono.CSharp {
  14
  15         public class ConstantFold {
  16
  17                 static Type[] binary_promotions = new Type[] {
  18                         TypeManager.decimal_type, TypeManager.double_type, TypeManager.float_type,
  19                         TypeManager.uint64_type, TypeManager.int64_type, TypeManager.uint32_type };
  20
  21                 //
  22                 // Performs the numeric promotions on the left and right expresions
  23                 // and desposits the results on `lc' and `rc'.
  24                 //
  25                 // On success, the types of `lc' and `rc' on output will always match,
  26                 // and the pair will be one of:
  27                 //
  28                 static void DoBinaryNumericPromotions (ref Constant left, ref Constant right)
  29                 {
  30                         Type ltype = left.Type;
  31                         Type rtype = right.Type;
  32
  33                         foreach (Type t in binary_promotions) {
  34                                 if (t == ltype || t == rtype) {
  35                                         left = left.ConvertImplicitly (t);
  36                                         right = right.ConvertImplicitly (t);
  37                                         return;
  38                                 }
  39                         }
  40
  41                         left = left.ConvertImplicitly (TypeManager.int32_type);
  42                         right = right.ConvertImplicitly (TypeManager.int32_type);
  43                 }
  44
  45                 internal static void Error_CompileTimeOverflow (Location loc)
  46                 {
  47                         Report.Error (220, loc, "The operation overflows at compile time in checked mode");
  48                 }
  49
  50                 /// <summary>
  51                 ///   Constant expression folder for binary operations.
  52                 ///
  53                 ///   Returns null if the expression can not be folded.
  54                 /// </summary>
  55                 static public Constant BinaryFold (EmitContext ec, Binary.Operator oper,
  56                                                      Constant left, Constant right, Location loc)
  57                 {
  58                         if (left is EmptyConstantCast)
  59                                 return BinaryFold (ec, oper, ((EmptyConstantCast)left).child, right, loc);
  60
  61                         if (right is EmptyConstantCast)
  62                                 return BinaryFold (ec, oper, left, ((EmptyConstantCast)right).child, loc);
  63
  64                         Type lt = left.Type;
  65                         Type rt = right.Type;
  66                         bool bool_res;
  67                         Constant result = null;
  68
  69                         if (lt == TypeManager.bool_type && lt == rt) {
  70                                 bool lv = ((BoolConstant) left ).Value;
  71                                 bool rv = ((BoolConstant) right).Value;
  72                                 switch (oper) {
  73                                 case Binary.Operator.BitwiseAnd:
  74                                 case Binary.Operator.LogicalAnd:
  75                                         return new BoolConstant (lv && rv, left.Location);
  76                                 case Binary.Operator.BitwiseOr:
  77                                 case Binary.Operator.LogicalOr:
  78                                         return new BoolConstant (lv || rv, left.Location);
  79                                 case Binary.Operator.ExclusiveOr:
  80                                         return new BoolConstant (lv ^ rv, left.Location);
  81                                 case Binary.Operator.Equality:
  82                                         return new BoolConstant (lv == rv, left.Location);
  83                                 case Binary.Operator.Inequality:
  84                                         return new BoolConstant (lv != rv, left.Location);
  85                                 }
  86                                 return null;
  87                         }
  88
  89                         //
  90                         // During an enum evaluation, none of the rules are valid
  91                         // Not sure whether it is bug in csc or in documentation
  92                         //
  93                         if (ec.InEnumContext){
  94                                 if (left is EnumConstant)
  95                                         left = ((EnumConstant) left).Child;
  96
  97                                 if (right is EnumConstant)
  98                                         right = ((EnumConstant) right).Child;
  99                         } else if (left is EnumConstant && rt == lt) {
 100                                 switch (oper){
 101                                         ///
 102                                         /// E operator |(E x, E y);
 103                                         /// E operator &(E x, E y);
 104                                         /// E operator ^(E x, E y);
 105                                         ///
 106                                         case Binary.Operator.BitwiseOr:
 107                                         case Binary.Operator.BitwiseAnd:
 108                                         case Binary.Operator.ExclusiveOr:
 109                                                 return BinaryFold (ec, oper, ((EnumConstant)left).Child,
 110                                                                 ((EnumConstant)right).Child, loc).TryReduce (ec, lt, loc);
 111
 112                                         ///
 113                                         /// U operator -(E x, E y);
 114                                         ///
 115                                         case Binary.Operator.Subtraction:
 116                                                 result = BinaryFold (ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
 117                                                 return result.TryReduce (ec, ((EnumConstant)left).Child.Type, loc);
 118
 119                                         ///
 120                                         /// bool operator ==(E x, E y);
 121                                         /// bool operator !=(E x, E y);
 122                                         /// bool operator <(E x, E y);
 123                                         /// bool operator >(E x, E y);
 124                                         /// bool operator <=(E x, E y);
 125                                         /// bool operator >=(E x, E y);
 126                                         ///
 127                                         case Binary.Operator.Equality:
 128                                         case Binary.Operator.Inequality:
 129                                         case Binary.Operator.LessThan:
 130                                         case Binary.Operator.GreaterThan:
 131                                         case Binary.Operator.LessThanOrEqual:
 132                                         case Binary.Operator.GreaterThanOrEqual:
 133                                                 return BinaryFold(ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
 134                                 }
 135                                 return null;
 136                         }
 137
 138                         switch (oper){
 139                         case Binary.Operator.BitwiseOr:
 140                                 DoBinaryNumericPromotions (ref left, ref right);
 141                                 if (left == null || right == null)
 142                                         return null;
 143
 144                                 if (left is IntConstant){
 145                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 146
 147                                         return new IntConstant (res, left.Location);
 148                                 }
 149                                 if (left is UIntConstant){
 150                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 151
 152                                         return new UIntConstant (res, left.Location);
 153                                 }
 154                                 if (left is LongConstant){
 155                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 156
 157                                         return new LongConstant (res, left.Location);
 158                                 }
 159                                 if (left is ULongConstant){
 160                                         ulong res = ((ULongConstant)left).Value |
 161                                                 ((ULongConstant)right).Value;
 162
 163                                         return new ULongConstant (res, left.Location);
 164                                 }
 165                                 break;
 166
 167                         case Binary.Operator.BitwiseAnd:
 168                                 DoBinaryNumericPromotions (ref left, ref right);
 169                                 if (left == null || right == null)
 170                                         return null;
 171
 172                                 ///
 173                                 /// int operator &(int x, int y);
 174                                 /// uint operator &(uint x, uint y);
 175                                 /// long operator &(long x, long y);
 176                                 /// ulong operator &(ulong x, ulong y);
 177                                 ///
 178                                 if (left is IntConstant){
 179                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 180                                         return new IntConstant (res, left.Location);
 181                                 }
 182                                 if (left is UIntConstant){
 183                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 184                                         return new UIntConstant (res, left.Location);
 185                                 }
 186                                 if (left is LongConstant){
 187                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 188                                         return new LongConstant (res, left.Location);
 189                                 }
 190                                 if (left is ULongConstant){
 191                                         ulong res = ((ULongConstant)left).Value &
 192                                                 ((ULongConstant)right).Value;
 193
 194                                         return new ULongConstant (res, left.Location);
 195                                 }
 196                                 break;
 197
 198                         case Binary.Operator.ExclusiveOr:
 199                                 DoBinaryNumericPromotions (ref left, ref right);
 200                                 if (left == null || right == null)
 201                                         return null;
 202
 203                                 if (left is IntConstant){
 204                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 205                                         return new IntConstant (res, left.Location);
 206                                 }
 207                                 if (left is UIntConstant){
 208                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 209
 210                                         return  new UIntConstant (res, left.Location);
 211                                 }
 212                                 if (left is LongConstant){
 213                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 214
 215                                         return new LongConstant (res, left.Location);
 216                                 }
 217                                 if (left is ULongConstant){
 218                                         ulong res = ((ULongConstant)left).Value ^
 219                                                 ((ULongConstant)right).Value;
 220
 221                                         return new ULongConstant (res, left.Location);
 222                                 }
 223                                 break;
 224
 225                         case Binary.Operator.Addition:
 226                                 //
 227                                 // If both sides are strings, then concatenate, if
 228                                 // one is a string, and the other is not, then defer
 229                                 // to runtime concatenation
 230                                 //
 231                                 if (lt == TypeManager.string_type || rt == TypeManager.string_type){
 232                                         if (lt == TypeManager.string_type && rt == TypeManager.string_type)
 233                                                 return new StringConstant (
 234                                                         ((StringConstant) left).Value +
 235                                                         ((StringConstant) right).Value, left.Location);
 236
 237                                         return null;
 238                                 }
 239
 240                                 //
 241                                 // handle "E operator + (E x, U y)"
 242                                 // handle "E operator + (Y y, E x)"
 243                                 //
 244                                 EnumConstant lc = left as EnumConstant;
 245                                 EnumConstant rc = right as EnumConstant;
 246                                 if (lc != null || rc != null){
 247                                         if (lc == null) {
 248                                                 lc = rc;
 249                                                 lt = lc.Type;
 250                                                 right = left;
 251                                         }
 252
 253                                         // U has to be implicitly convetible to E.base
 254                                         right = right.ConvertImplicitly (lc.Child.Type);
 255                                         if (right == null)
 256                                                 return null;
 257
 258                                         result = BinaryFold (ec, oper, lc.Child, right, loc);
 259                                         if (result == null)
 260                                                 return null;
 261
 262                                         result = result.TryReduce (ec, lt, loc);
 263                                         if (result == null)
 264                                                 return null;
 265
 266                                         return new EnumConstant (result, lt);
 267                                 }
 268
 269                                 DoBinaryNumericPromotions (ref left, ref right);
 270                                 if (left == null || right == null)
 271                                         return null;
 272
 273                                 try {
 274                                         if (left is DoubleConstant){
 275                                                 double res;
 276
 277                                                 if (ec.ConstantCheckState)
 278                                                         res = checked (((DoubleConstant) left).Value +
 279                                                                        ((DoubleConstant) right).Value);
 280                                                 else
 281                                                         res = unchecked (((DoubleConstant) left).Value +
 282                                                                          ((DoubleConstant) right).Value);
 283
 284                                                 return new DoubleConstant (res, left.Location);
 285                                         }
 286                                         if (left is FloatConstant){
 287                                                 float res;
 288
 289                                                 if (ec.ConstantCheckState)
 290                                                         res = checked (((FloatConstant) left).Value +
 291                                                                        ((FloatConstant) right).Value);
 292                                                 else
 293                                                         res = unchecked (((FloatConstant) left).Value +
 294                                                                          ((FloatConstant) right).Value);
 295
 296                                                 result = new FloatConstant (res, left.Location);
 297                                         } else if (left is ULongConstant){
 298                                                 ulong res;
 299
 300                                                 if (ec.ConstantCheckState)
 301                                                         res = checked (((ULongConstant) left).Value +
 302                                                                        ((ULongConstant) right).Value);
 303                                                 else
 304                                                         res = unchecked (((ULongConstant) left).Value +
 305                                                                          ((ULongConstant) right).Value);
 306
 307                                                 result = new ULongConstant (res, left.Location);
 308                                         } else if (left is LongConstant){
 309                                                 long res;
 310
 311                                                 if (ec.ConstantCheckState)
 312                                                         res = checked (((LongConstant) left).Value +
 313                                                                        ((LongConstant) right).Value);
 314                                                 else
 315                                                         res = unchecked (((LongConstant) left).Value +
 316                                                                          ((LongConstant) right).Value);
 317
 318                                                 result = new LongConstant (res, left.Location);
 319                                         } else if (left is UIntConstant){
 320                                                 uint res;
 321
 322                                                 if (ec.ConstantCheckState)
 323                                                         res = checked (((UIntConstant) left).Value +
 324                                                                        ((UIntConstant) right).Value);
 325                                                 else
 326                                                         res = unchecked (((UIntConstant) left).Value +
 327                                                                          ((UIntConstant) right).Value);
 328
 329                                                 result = new UIntConstant (res, left.Location);
 330                                         } else if (left is IntConstant){
 331                                                 int res;
 332
 333                                                 if (ec.ConstantCheckState)
 334                                                         res = checked (((IntConstant) left).Value +
 335                                                                        ((IntConstant) right).Value);
 336                                                 else
 337                                                         res = unchecked (((IntConstant) left).Value +
 338                                                                          ((IntConstant) right).Value);
 339
 340                                                 result = new IntConstant (res, left.Location);
 341                                         } else if (left is DecimalConstant) {
 342                                                 decimal res;
 343
 344                                                 if (ec.ConstantCheckState)
 345                                                         res = checked (((DecimalConstant) left).Value +
 346                                                                 ((DecimalConstant) right).Value);
 347                                                 else
 348                                                         res = unchecked (((DecimalConstant) left).Value +
 349                                                                 ((DecimalConstant) right).Value);
 350
 351                                                 result = new DecimalConstant (res, left.Location);
 352                                         } else {
 353                                                 throw new Exception ( "Unexepected addition input: " + left);
 354                                         }
 355                                 } catch (OverflowException){
 356                                         Error_CompileTimeOverflow (loc);
 357                                 }
 358
 359                                 return result;
 360
 361                         case Binary.Operator.Subtraction:
 362                                 //
 363                                 // handle "E operator - (E x, U y)"
 364                                 // handle "E operator - (Y y, E x)"
 365                                 //
 366                                 lc = left as EnumConstant;
 367                                 rc = right as EnumConstant;
 368                                 if (lc != null || rc != null){
 369                                         if (lc == null) {
 370                                                 lc = rc;
 371                                                 lt = lc.Type;
 372                                                 right = left;
 373                                         }
 374
 375                                         // U has to be implicitly convetible to E.base
 376                                         right = right.ConvertImplicitly (lc.Child.Type);
 377                                         if (right == null)
 378                                                 return null;
 379
 380                                         result = BinaryFold (ec, oper, lc.Child, right, loc);
 381                                         if (result == null)
 382                                                 return null;
 383
 384                                         result = result.TryReduce (ec, lt, loc);
 385                                         if (result == null)
 386                                                 return null;
 387
 388                                         return new EnumConstant (result, lt);
 389                                 }
 390
 391                                 DoBinaryNumericPromotions (ref left, ref right);
 392                                 if (left == null || right == null)
 393                                         return null;
 394
 395                                 try {
 396                                         if (left is DoubleConstant){
 397                                                 double res;
 398
 399                                                 if (ec.ConstantCheckState)
 400                                                         res = checked (((DoubleConstant) left).Value -
 401                                                                        ((DoubleConstant) right).Value);
 402                                                 else
 403                                                         res = unchecked (((DoubleConstant) left).Value -
 404                                                                          ((DoubleConstant) right).Value);
 405
 406                                                 result = new DoubleConstant (res, left.Location);
 407                                         } else if (left is FloatConstant){
 408                                                 float res;
 409
 410                                                 if (ec.ConstantCheckState)
 411                                                         res = checked (((FloatConstant) left).Value -
 412                                                                        ((FloatConstant) right).Value);
 413                                                 else
 414                                                         res = unchecked (((FloatConstant) left).Value -
 415                                                                          ((FloatConstant) right).Value);
 416
 417                                                 result = new FloatConstant (res, left.Location);
 418                                         } else if (left is ULongConstant){
 419                                                 ulong res;
 420
 421                                                 if (ec.ConstantCheckState)
 422                                                         res = checked (((ULongConstant) left).Value -
 423                                                                        ((ULongConstant) right).Value);
 424                                                 else
 425                                                         res = unchecked (((ULongConstant) left).Value -
 426                                                                          ((ULongConstant) right).Value);
 427
 428                                                 result = new ULongConstant (res, left.Location);
 429                                         } else if (left is LongConstant){
 430                                                 long res;
 431
 432                                                 if (ec.ConstantCheckState)
 433                                                         res = checked (((LongConstant) left).Value -
 434                                                                        ((LongConstant) right).Value);
 435                                                 else
 436                                                         res = unchecked (((LongConstant) left).Value -
 437                                                                          ((LongConstant) right).Value);
 438
 439                                                 result = new LongConstant (res, left.Location);
 440                                         } else if (left is UIntConstant){
 441                                                 uint res;
 442
 443                                                 if (ec.ConstantCheckState)
 444                                                         res = checked (((UIntConstant) left).Value -
 445                                                                        ((UIntConstant) right).Value);
 446                                                 else
 447                                                         res = unchecked (((UIntConstant) left).Value -
 448                                                                          ((UIntConstant) right).Value);
 449
 450                                                 result = new UIntConstant (res, left.Location);
 451                                         } else if (left is IntConstant){
 452                                                 int res;
 453
 454                                                 if (ec.ConstantCheckState)
 455                                                         res = checked (((IntConstant) left).Value -
 456                                                                        ((IntConstant) right).Value);
 457                                                 else
 458                                                         res = unchecked (((IntConstant) left).Value -
 459                                                                          ((IntConstant) right).Value);
 460
 461                                                 result = new IntConstant (res, left.Location);
 462                                         } else if (left is DecimalConstant) {
 463                                                 decimal res;
 464
 465                                                 if (ec.ConstantCheckState)
 466                                                         res = checked (((DecimalConstant) left).Value -
 467                                                                 ((DecimalConstant) right).Value);
 468                                                 else
 469                                                         res = unchecked (((DecimalConstant) left).Value -
 470                                                                 ((DecimalConstant) right).Value);
 471
 472                                                 return new DecimalConstant (res, left.Location);
 473                                         } else {
 474                                                 throw new Exception ( "Unexepected subtraction input: " + left);
 475                                         }
 476                                 } catch (OverflowException){
 477                                         Error_CompileTimeOverflow (loc);
 478                                 }
 479
 480                                 return result;
 481
 482                         case Binary.Operator.Multiply:
 483                                 DoBinaryNumericPromotions (ref left, ref right);
 484                                 if (left == null || right == null)
 485                                         return null;
 486
 487                                 try {
 488                                         if (left is DoubleConstant){
 489                                                 double res;
 490
 491                                                 if (ec.ConstantCheckState)
 492                                                         res = checked (((DoubleConstant) left).Value *
 493                                                                 ((DoubleConstant) right).Value);
 494                                                 else
 495                                                         res = unchecked (((DoubleConstant) left).Value *
 496                                                                 ((DoubleConstant) right).Value);
 497
 498                                                 return new DoubleConstant (res, left.Location);
 499                                         } else if (left is FloatConstant){
 500                                                 float res;
 501
 502                                                 if (ec.ConstantCheckState)
 503                                                         res = checked (((FloatConstant) left).Value *
 504                                                                 ((FloatConstant) right).Value);
 505                                                 else
 506                                                         res = unchecked (((FloatConstant) left).Value *
 507                                                                 ((FloatConstant) right).Value);
 508
 509                                                 return new FloatConstant (res, left.Location);
 510                                         } else if (left is ULongConstant){
 511                                                 ulong res;
 512
 513                                                 if (ec.ConstantCheckState)
 514                                                         res = checked (((ULongConstant) left).Value *
 515                                                                 ((ULongConstant) right).Value);
 516                                                 else
 517                                                         res = unchecked (((ULongConstant) left).Value *
 518                                                                 ((ULongConstant) right).Value);
 519
 520                                                 return new ULongConstant (res, left.Location);
 521                                         } else if (left is LongConstant){
 522                                                 long res;
 523
 524                                                 if (ec.ConstantCheckState)
 525                                                         res = checked (((LongConstant) left).Value *
 526                                                                 ((LongConstant) right).Value);
 527                                                 else
 528                                                         res = unchecked (((LongConstant) left).Value *
 529                                                                 ((LongConstant) right).Value);
 530
 531                                                 return new LongConstant (res, left.Location);
 532                                         } else if (left is UIntConstant){
 533                                                 uint res;
 534
 535                                                 if (ec.ConstantCheckState)
 536                                                         res = checked (((UIntConstant) left).Value *
 537                                                                 ((UIntConstant) right).Value);
 538                                                 else
 539                                                         res = unchecked (((UIntConstant) left).Value *
 540                                                                 ((UIntConstant) right).Value);
 541
 542                                                 return new UIntConstant (res, left.Location);
 543                                         } else if (left is IntConstant){
 544                                                 int res;
 545
 546                                                 if (ec.ConstantCheckState)
 547                                                         res = checked (((IntConstant) left).Value *
 548                                                                 ((IntConstant) right).Value);
 549                                                 else
 550                                                         res = unchecked (((IntConstant) left).Value *
 551                                                                 ((IntConstant) right).Value);
 552
 553                                                 return new IntConstant (res, left.Location);
 554                                         } else if (left is DecimalConstant) {
 555                                                 decimal res;
 556
 557                                                 if (ec.ConstantCheckState)
 558                                                         res = checked (((DecimalConstant) left).Value *
 559                                                                 ((DecimalConstant) right).Value);
 560                                                 else
 561                                                         res = unchecked (((DecimalConstant) left).Value *
 562                                                                 ((DecimalConstant) right).Value);
 563
 564                                                 return new DecimalConstant (res, left.Location);
 565                                         } else {
 566                                                 throw new Exception ( "Unexepected multiply input: " + left);
 567                                         }
 568                                 } catch (OverflowException){
 569                                         Error_CompileTimeOverflow (loc);
 570                                 }
 571                                 break;
 572
 573                         case Binary.Operator.Division:
 574                                 DoBinaryNumericPromotions (ref left, ref right);
 575                                 if (left == null || right == null)
 576                                         return null;
 577
 578                                 try {
 579                                         if (left is DoubleConstant){
 580                                                 double res;
 581
 582                                                 if (ec.ConstantCheckState)
 583                                                         res = checked (((DoubleConstant) left).Value /
 584                                                                 ((DoubleConstant) right).Value);
 585                                                 else
 586                                                         res = unchecked (((DoubleConstant) left).Value /
 587                                                                 ((DoubleConstant) right).Value);
 588
 589                                                 return new DoubleConstant (res, left.Location);
 590                                         } else if (left is FloatConstant){
 591                                                 float res;
 592
 593                                                 if (ec.ConstantCheckState)
 594                                                         res = checked (((FloatConstant) left).Value /
 595                                                                 ((FloatConstant) right).Value);
 596                                                 else
 597                                                         res = unchecked (((FloatConstant) left).Value /
 598                                                                 ((FloatConstant) right).Value);
 599
 600                                                 return new FloatConstant (res, left.Location);
 601                                         } else if (left is ULongConstant){
 602                                                 ulong res;
 603
 604                                                 if (ec.ConstantCheckState)
 605                                                         res = checked (((ULongConstant) left).Value /
 606                                                                 ((ULongConstant) right).Value);
 607                                                 else
 608                                                         res = unchecked (((ULongConstant) left).Value /
 609                                                                 ((ULongConstant) right).Value);
 610
 611                                                 return new ULongConstant (res, left.Location);
 612                                         } else if (left is LongConstant){
 613                                                 long res;
 614
 615                                                 if (ec.ConstantCheckState)
 616                                                         res = checked (((LongConstant) left).Value /
 617                                                                 ((LongConstant) right).Value);
 618                                                 else
 619                                                         res = unchecked (((LongConstant) left).Value /
 620                                                                 ((LongConstant) right).Value);
 621
 622                                                 return new LongConstant (res, left.Location);
 623                                         } else if (left is UIntConstant){
 624                                                 uint res;
 625
 626                                                 if (ec.ConstantCheckState)
 627                                                         res = checked (((UIntConstant) left).Value /
 628                                                                 ((UIntConstant) right).Value);
 629                                                 else
 630                                                         res = unchecked (((UIntConstant) left).Value /
 631                                                                 ((UIntConstant) right).Value);
 632
 633                                                 return new UIntConstant (res, left.Location);
 634                                         } else if (left is IntConstant){
 635                                                 int res;
 636
 637                                                 if (ec.ConstantCheckState)
 638                                                         res = checked (((IntConstant) left).Value /
 639                                                                 ((IntConstant) right).Value);
 640                                                 else
 641                                                         res = unchecked (((IntConstant) left).Value /
 642                                                                 ((IntConstant) right).Value);
 643
 644                                                 return new IntConstant (res, left.Location);
 645                                         } else if (left is DecimalConstant) {
 646                                                 decimal res;
 647
 648                                                 if (ec.ConstantCheckState)
 649                                                         res = checked (((DecimalConstant) left).Value /
 650                                                                 ((DecimalConstant) right).Value);
 651                                                 else
 652                                                         res = unchecked (((DecimalConstant) left).Value /
 653                                                                 ((DecimalConstant) right).Value);
 654
 655                                                 return new DecimalConstant (res, left.Location);
 656                                         } else {
 657                                                 throw new Exception ( "Unexepected division input: " + left);
 658                                         }
 659                                 } catch (OverflowException){
 660                                         Error_CompileTimeOverflow (loc);
 661
 662                                 } catch (DivideByZeroException) {
 663                                         Report.Error (020, loc, "Division by constant zero");
 664                                 }
 665
 666                                 break;
 667
 668                         case Binary.Operator.Modulus:
 669                                 DoBinaryNumericPromotions (ref left, ref right);
 670                                 if (left == null || right == null)
 671                                         return null;
 672
 673                                 try {
 674                                         if (left is DoubleConstant){
 675                                                 double res;
 676
 677                                                 if (ec.ConstantCheckState)
 678                                                         res = checked (((DoubleConstant) left).Value %
 679                                                                        ((DoubleConstant) right).Value);
 680                                                 else
 681                                                         res = unchecked (((DoubleConstant) left).Value %
 682                                                                          ((DoubleConstant) right).Value);
 683
 684                                                 return new DoubleConstant (res, left.Location);
 685                                         } else if (left is FloatConstant){
 686                                                 float res;
 687
 688                                                 if (ec.ConstantCheckState)
 689                                                         res = checked (((FloatConstant) left).Value %
 690                                                                        ((FloatConstant) right).Value);
 691                                                 else
 692                                                         res = unchecked (((FloatConstant) left).Value %
 693                                                                          ((FloatConstant) right).Value);
 694
 695                                                 return new FloatConstant (res, left.Location);
 696                                         } else if (left is ULongConstant){
 697                                                 ulong res;
 698
 699                                                 if (ec.ConstantCheckState)
 700                                                         res = checked (((ULongConstant) left).Value %
 701                                                                        ((ULongConstant) right).Value);
 702                                                 else
 703                                                         res = unchecked (((ULongConstant) left).Value %
 704                                                                          ((ULongConstant) right).Value);
 705
 706                                                 return new ULongConstant (res, left.Location);
 707                                         } else if (left is LongConstant){
 708                                                 long res;
 709
 710                                                 if (ec.ConstantCheckState)
 711                                                         res = checked (((LongConstant) left).Value %
 712                                                                        ((LongConstant) right).Value);
 713                                                 else
 714                                                         res = unchecked (((LongConstant) left).Value %
 715                                                                          ((LongConstant) right).Value);
 716
 717                                                 return new LongConstant (res, left.Location);
 718                                         } else if (left is UIntConstant){
 719                                                 uint res;
 720
 721                                                 if (ec.ConstantCheckState)
 722                                                         res = checked (((UIntConstant) left).Value %
 723                                                                        ((UIntConstant) right).Value);
 724                                                 else
 725                                                         res = unchecked (((UIntConstant) left).Value %
 726                                                                          ((UIntConstant) right).Value);
 727
 728                                                 return new UIntConstant (res, left.Location);
 729                                         } else if (left is IntConstant){
 730                                                 int res;
 731
 732                                                 if (ec.ConstantCheckState)
 733                                                         res = checked (((IntConstant) left).Value %
 734                                                                        ((IntConstant) right).Value);
 735                                                 else
 736                                                         res = unchecked (((IntConstant) left).Value %
 737                                                                          ((IntConstant) right).Value);
 738
 739                                                 return new IntConstant (res, left.Location);
 740                                         } else {
 741                                                 throw new Exception ( "Unexepected modulus input: " + left);
 742                                         }
 743                                 } catch (DivideByZeroException){
 744                                         Report.Error (020, loc, "Division by constant zero");
 745                                 } catch (OverflowException){
 746                                         Error_CompileTimeOverflow (loc);
 747                                 }
 748                                 break;
 749
 750                                 //
 751                                 // There is no overflow checking on left shift
 752                                 //
 753                         case Binary.Operator.LeftShift:
 754                                 IntConstant ic = right.ConvertImplicitly (TypeManager.int32_type) as IntConstant;
 755                                 if (ic == null){
 756                                         Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 757                                         return null;
 758                                 }
 759
 760                                 int lshift_val = ic.Value;
 761                                 if (left.Type == TypeManager.uint64_type)
 762                                         return new ULongConstant (((ULongConstant)left).Value << lshift_val, left.Location);
 763                                 if (left.Type == TypeManager.int64_type)
 764                                         return new LongConstant (((LongConstant)left).Value << lshift_val, left.Location);
 765                                 if (left.Type == TypeManager.uint32_type)
 766                                         return new UIntConstant (((UIntConstant)left).Value << lshift_val, left.Location);
 767
 768                                 left = left.ConvertImplicitly (TypeManager.int32_type);
 769                                 if (left.Type == TypeManager.int32_type)
 770                                         return new IntConstant (((IntConstant)left).Value << lshift_val, left.Location);
 771
 772                                 Binary.Error_OperatorCannotBeApplied (loc, "<<", lt, rt);
 773                                 break;
 774
 775                                 //
 776                                 // There is no overflow checking on right shift
 777                                 //
 778                         case Binary.Operator.RightShift:
 779                                 IntConstant sic = right.ConvertImplicitly (TypeManager.int32_type) as IntConstant;
 780                                 if (sic == null){
 781                                         Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 782                                         return null;
 783                                 }
 784                                 int rshift_val = sic.Value;
 785                                 if (left.Type == TypeManager.uint64_type)
 786                                         return new ULongConstant (((ULongConstant)left).Value >> rshift_val, left.Location);
 787                                 if (left.Type == TypeManager.int64_type)
 788                                         return new LongConstant (((LongConstant)left).Value >> rshift_val, left.Location);
 789                                 if (left.Type == TypeManager.uint32_type)
 790                                         return new UIntConstant (((UIntConstant)left).Value >> rshift_val, left.Location);
 791
 792                                 left = left.ConvertImplicitly (TypeManager.int32_type);
 793                                 if (left.Type == TypeManager.int32_type)
 794                                         return new IntConstant (((IntConstant)left).Value >> rshift_val, left.Location);
 795
 796                                 Binary.Error_OperatorCannotBeApplied (loc, ">>", lt, rt);
 797                                 break;
 798
 799                         case Binary.Operator.Equality:
 800                                 if (left is NullConstant){
 801                                         if (right is NullConstant)
 802                                                 return new BoolConstant (true, left.Location);
 803                                         else if (right is StringConstant)
 804                                                 return new BoolConstant (
 805                                                         ((StringConstant) right).Value == null, left.Location);
 806                                 } else if (right is NullConstant){
 807                                         if (left is NullConstant)
 808                                                 return new BoolConstant (true, left.Location);
 809                                         else if (left is StringConstant)
 810                                                 return new BoolConstant (
 811                                                         ((StringConstant) left).Value == null, left.Location);
 812                                 }
 813                                 if (left is StringConstant && right is StringConstant){
 814                                         return new BoolConstant (
 815                                                 ((StringConstant) left).Value ==
 816                                                 ((StringConstant) right).Value, left.Location);
 817
 818                                 }
 819
 820                                 DoBinaryNumericPromotions (ref left, ref right);
 821                                 if (left == null || right == null)
 822                                         return null;
 823
 824                                 bool_res = false;
 825                                 if (left is DoubleConstant)
 826                                         bool_res = ((DoubleConstant) left).Value ==
 827                                                 ((DoubleConstant) right).Value;
 828                                 else if (left is FloatConstant)
 829                                         bool_res = ((FloatConstant) left).Value ==
 830                                                 ((FloatConstant) right).Value;
 831                                 else if (left is ULongConstant)
 832                                         bool_res = ((ULongConstant) left).Value ==
 833                                                 ((ULongConstant) right).Value;
 834                                 else if (left is LongConstant)
 835                                         bool_res = ((LongConstant) left).Value ==
 836                                                 ((LongConstant) right).Value;
 837                                 else if (left is UIntConstant)
 838                                         bool_res = ((UIntConstant) left).Value ==
 839                                                 ((UIntConstant) right).Value;
 840                                 else if (left is IntConstant)
 841                                         bool_res = ((IntConstant) left).Value ==
 842                                                 ((IntConstant) right).Value;
 843                                 else
 844                                         return null;
 845
 846                                 return new BoolConstant (bool_res, left.Location);
 847
 848                         case Binary.Operator.Inequality:
 849                                 if (left is NullConstant){
 850                                         if (right is NullConstant)
 851                                                 return new BoolConstant (false, left.Location);
 852                                         else if (right is StringConstant)
 853                                                 return new BoolConstant (
 854                                                         ((StringConstant) right).Value != null, left.Location);
 855                                 } else if (right is NullConstant){
 856                                         if (left is NullConstant)
 857                                                 return new BoolConstant (false, left.Location);
 858                                         else if (left is StringConstant)
 859                                                 return new BoolConstant (
 860                                                         ((StringConstant) left).Value != null, left.Location);
 861                                 }
 862                                 if (left is StringConstant && right is StringConstant){
 863                                         return new BoolConstant (
 864                                                 ((StringConstant) left).Value !=
 865                                                 ((StringConstant) right).Value, left.Location);
 866
 867                                 }
 868
 869                                 DoBinaryNumericPromotions (ref left, ref right);
 870                                 if (left == null || right == null)
 871                                         return null;
 872
 873                                 bool_res = false;
 874                                 if (left is DoubleConstant)
 875                                         bool_res = ((DoubleConstant) left).Value !=
 876                                                 ((DoubleConstant) right).Value;
 877                                 else if (left is FloatConstant)
 878                                         bool_res = ((FloatConstant) left).Value !=
 879                                                 ((FloatConstant) right).Value;
 880                                 else if (left is ULongConstant)
 881                                         bool_res = ((ULongConstant) left).Value !=
 882                                                 ((ULongConstant) right).Value;
 883                                 else if (left is LongConstant)
 884                                         bool_res = ((LongConstant) left).Value !=
 885                                                 ((LongConstant) right).Value;
 886                                 else if (left is UIntConstant)
 887                                         bool_res = ((UIntConstant) left).Value !=
 888                                                 ((UIntConstant) right).Value;
 889                                 else if (left is IntConstant)
 890                                         bool_res = ((IntConstant) left).Value !=
 891                                                 ((IntConstant) right).Value;
 892                                 else
 893                                         return null;
 894
 895                                 return new BoolConstant (bool_res, left.Location);
 896
 897                         case Binary.Operator.LessThan:
 898                                 DoBinaryNumericPromotions (ref left, ref right);
 899                                 if (left == null || right == null)
 900                                         return null;
 901
 902                                 bool_res = false;
 903                                 if (left is DoubleConstant)
 904                                         bool_res = ((DoubleConstant) left).Value <
 905                                                 ((DoubleConstant) right).Value;
 906                                 else if (left is FloatConstant)
 907                                         bool_res = ((FloatConstant) left).Value <
 908                                                 ((FloatConstant) right).Value;
 909                                 else if (left is ULongConstant)
 910                                         bool_res = ((ULongConstant) left).Value <
 911                                                 ((ULongConstant) right).Value;
 912                                 else if (left is LongConstant)
 913                                         bool_res = ((LongConstant) left).Value <
 914                                                 ((LongConstant) right).Value;
 915                                 else if (left is UIntConstant)
 916                                         bool_res = ((UIntConstant) left).Value <
 917                                                 ((UIntConstant) right).Value;
 918                                 else if (left is IntConstant)
 919                                         bool_res = ((IntConstant) left).Value <
 920                                                 ((IntConstant) right).Value;
 921                                 else
 922                                         return null;
 923
 924                                 return new BoolConstant (bool_res, left.Location);
 925
 926                         case Binary.Operator.GreaterThan:
 927                                 DoBinaryNumericPromotions (ref left, ref right);
 928                                 if (left == null || right == null)
 929                                         return null;
 930
 931                                 bool_res = false;
 932                                 if (left is DoubleConstant)
 933                                         bool_res = ((DoubleConstant) left).Value >
 934                                                 ((DoubleConstant) right).Value;
 935                                 else if (left is FloatConstant)
 936                                         bool_res = ((FloatConstant) left).Value >
 937                                                 ((FloatConstant) right).Value;
 938                                 else if (left is ULongConstant)
 939                                         bool_res = ((ULongConstant) left).Value >
 940                                                 ((ULongConstant) right).Value;
 941                                 else if (left is LongConstant)
 942                                         bool_res = ((LongConstant) left).Value >
 943                                                 ((LongConstant) right).Value;
 944                                 else if (left is UIntConstant)
 945                                         bool_res = ((UIntConstant) left).Value >
 946                                                 ((UIntConstant) right).Value;
 947                                 else if (left is IntConstant)
 948                                         bool_res = ((IntConstant) left).Value >
 949                                                 ((IntConstant) right).Value;
 950                                 else
 951                                         return null;
 952
 953                                 return new BoolConstant (bool_res, left.Location);
 954
 955                         case Binary.Operator.GreaterThanOrEqual:
 956                                 DoBinaryNumericPromotions (ref left, ref right);
 957                                 if (left == null || right == null)
 958                                         return null;
 959
 960                                 bool_res = false;
 961                                 if (left is DoubleConstant)
 962                                         bool_res = ((DoubleConstant) left).Value >=
 963                                                 ((DoubleConstant) right).Value;
 964                                 else if (left is FloatConstant)
 965                                         bool_res = ((FloatConstant) left).Value >=
 966                                                 ((FloatConstant) right).Value;
 967                                 else if (left is ULongConstant)
 968                                         bool_res = ((ULongConstant) left).Value >=
 969                                                 ((ULongConstant) right).Value;
 970                                 else if (left is LongConstant)
 971                                         bool_res = ((LongConstant) left).Value >=
 972                                                 ((LongConstant) right).Value;
 973                                 else if (left is UIntConstant)
 974                                         bool_res = ((UIntConstant) left).Value >=
 975                                                 ((UIntConstant) right).Value;
 976                                 else if (left is IntConstant)
 977                                         bool_res = ((IntConstant) left).Value >=
 978                                                 ((IntConstant) right).Value;
 979                                 else
 980                                         return null;
 981
 982                                 return new BoolConstant (bool_res, left.Location);
 983
 984                         case Binary.Operator.LessThanOrEqual:
 985                                 DoBinaryNumericPromotions (ref left, ref right);
 986                                 if (left == null || right == null)
 987                                         return null;
 988
 989                                 bool_res = false;
 990                                 if (left is DoubleConstant)
 991                                         bool_res = ((DoubleConstant) left).Value <=
 992                                                 ((DoubleConstant) right).Value;
 993                                 else if (left is FloatConstant)
 994                                         bool_res = ((FloatConstant) left).Value <=
 995                                                 ((FloatConstant) right).Value;
 996                                 else if (left is ULongConstant)
 997                                         bool_res = ((ULongConstant) left).Value <=
 998                                                 ((ULongConstant) right).Value;
 999                                 else if (left is LongConstant)
1000                                         bool_res = ((LongConstant) left).Value <=
1001                                                 ((LongConstant) right).Value;
1002                                 else if (left is UIntConstant)
1003                                         bool_res = ((UIntConstant) left).Value <=
1004                                                 ((UIntConstant) right).Value;
1005                                 else if (left is IntConstant)
1006                                         bool_res = ((IntConstant) left).Value <=
1007                                                 ((IntConstant) right).Value;
1008                                 else
1009                                         return null;
1010
1011                                 return new BoolConstant (bool_res, left.Location);
1012                         }
1013
1014                         return null;
1015                 }
1016         }
1017 }