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 // Copyright 2002, 2003 Ximian, Inc.
   9 // Copyright 2003-2008, Novell, Inc.
  10 //
  11 using System;
  12
  13 namespace Mono.CSharp {
  14
  15         public class ConstantFold {
  16
  17                 static TypeSpec[] binary_promotions;
  18
  19                 public static TypeSpec[] BinaryPromotionsTypes {
  20                         get {
  21                                 if (binary_promotions == null) {
  22                                          binary_promotions = new TypeSpec[] {
  23                                                 TypeManager.decimal_type, TypeManager.double_type, TypeManager.float_type,
  24                                                 TypeManager.uint64_type, TypeManager.int64_type, TypeManager.uint32_type };
  25                                 }
  26
  27                                 return binary_promotions;
  28                         }
  29                 }
  30
  31                 public static void Reset ()
  32                 {
  33                         binary_promotions = null;
  34                 }
  35
  36                 //
  37                 // Performs the numeric promotions on the left and right expresions
  38                 // and deposits the results on `lc' and `rc'.
  39                 //
  40                 // On success, the types of `lc' and `rc' on output will always match,
  41                 // and the pair will be one of:
  42                 //
  43                 // TODO: BinaryFold should be called as an optimization step only,
  44                 // error checking here is weak
  45                 //
  46                 static bool DoBinaryNumericPromotions (ResolveContext rc, ref Constant left, ref Constant right)
  47                 {
  48                         TypeSpec ltype = left.Type;
  49                         TypeSpec rtype = right.Type;
  50
  51                         foreach (TypeSpec t in BinaryPromotionsTypes) {
  52                                 if (t == ltype)
  53                                         return t == rtype || ConvertPromotion (rc, ref right, ref left, t);
  54
  55                                 if (t == rtype)
  56                                         return t == ltype || ConvertPromotion (rc, ref left, ref right, t);
  57                         }
  58
  59                         left = left.ConvertImplicitly (rc, TypeManager.int32_type);
  60                         right = right.ConvertImplicitly (rc, TypeManager.int32_type);
  61                         return left != null && right != null;
  62                 }
  63
  64                 static bool ConvertPromotion (ResolveContext rc, ref Constant prim, ref Constant second, TypeSpec type)
  65                 {
  66                         Constant c = prim.ConvertImplicitly (rc, type);
  67                         if (c != null) {
  68                                 prim = c;
  69                                 return true;
  70                         }
  71
  72                         if (type == TypeManager.uint32_type) {
  73                                 type = TypeManager.int64_type;
  74                                 prim = prim.ConvertImplicitly (rc, type);
  75                                 second = second.ConvertImplicitly (rc, type);
  76                                 return prim != null && second != null;
  77                         }
  78
  79                         return false;
  80                 }
  81
  82                 internal static void Error_CompileTimeOverflow (ResolveContext rc, Location loc)
  83                 {
  84                         rc.Report.Error (220, loc, "The operation overflows at compile time in checked mode");
  85                 }
  86
  87                 /// <summary>
  88                 ///   Constant expression folder for binary operations.
  89                 ///
  90                 ///   Returns null if the expression can not be folded.
  91                 /// </summary>
  92                 static public Constant BinaryFold (ResolveContext ec, Binary.Operator oper,
  93                                                      Constant left, Constant right, Location loc)
  94                 {
  95                         Constant result = null;
  96
  97                         if (left is EmptyConstantCast)
  98                                 return BinaryFold (ec, oper, ((EmptyConstantCast)left).child, right, loc);
  99
 100                         if (left is SideEffectConstant) {
 101                                 result = BinaryFold (ec, oper, ((SideEffectConstant) left).value, right, loc);
 102                                 if (result == null)
 103                                         return null;
 104                                 return new SideEffectConstant (result, left, loc);
 105                         }
 106
 107                         if (right is EmptyConstantCast)
 108                                 return BinaryFold (ec, oper, left, ((EmptyConstantCast)right).child, loc);
 109
 110                         if (right is SideEffectConstant) {
 111                                 result = BinaryFold (ec, oper, left, ((SideEffectConstant) right).value, loc);
 112                                 if (result == null)
 113                                         return null;
 114                                 return new SideEffectConstant (result, right, loc);
 115                         }
 116
 117                         TypeSpec lt = left.Type;
 118                         TypeSpec rt = right.Type;
 119                         bool bool_res;
 120
 121                         if (lt == TypeManager.bool_type && lt == rt) {
 122                                 bool lv = (bool) left.GetValue ();
 123                                 bool rv = (bool) right.GetValue ();
 124                                 switch (oper) {
 125                                 case Binary.Operator.BitwiseAnd:
 126                                 case Binary.Operator.LogicalAnd:
 127                                         return new BoolConstant (lv && rv, left.Location);
 128                                 case Binary.Operator.BitwiseOr:
 129                                 case Binary.Operator.LogicalOr:
 130                                         return new BoolConstant (lv || rv, left.Location);
 131                                 case Binary.Operator.ExclusiveOr:
 132                                         return new BoolConstant (lv ^ rv, left.Location);
 133                                 case Binary.Operator.Equality:
 134                                         return new BoolConstant (lv == rv, left.Location);
 135                                 case Binary.Operator.Inequality:
 136                                         return new BoolConstant (lv != rv, left.Location);
 137                                 }
 138                                 return null;
 139                         }
 140
 141                         //
 142                         // During an enum evaluation, none of the rules are valid
 143                         // Not sure whether it is bug in csc or in documentation
 144                         //
 145                         if (ec.HasSet (ResolveContext.Options.EnumScope)){
 146                                 if (left is EnumConstant)
 147                                         left = ((EnumConstant) left).Child;
 148
 149                                 if (right is EnumConstant)
 150                                         right = ((EnumConstant) right).Child;
 151                         } else if (left is EnumConstant && rt == lt) {
 152                                 switch (oper){
 153                                         ///
 154                                         /// E operator |(E x, E y);
 155                                         /// E operator &(E x, E y);
 156                                         /// E operator ^(E x, E y);
 157                                         ///
 158                                         case Binary.Operator.BitwiseOr:
 159                                         case Binary.Operator.BitwiseAnd:
 160                                         case Binary.Operator.ExclusiveOr:
 161                                                 result = BinaryFold (ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
 162                                                 if (result != null)
 163                                                         result = result.Resolve (ec).TryReduce (ec, lt, loc);
 164                                                 return result;
 165
 166                                         ///
 167                                         /// U operator -(E x, E y);
 168                                         ///
 169                                         case Binary.Operator.Subtraction:
 170                                                 result = BinaryFold (ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
 171                                                 if (result != null)
 172                                                         result = result.Resolve (ec).TryReduce (ec, ((EnumConstant)left).Child.Type, loc);
 173                                                 return result;
 174
 175                                         ///
 176                                         /// bool operator ==(E x, E y);
 177                                         /// bool operator !=(E x, E y);
 178                                         /// bool operator <(E x, E y);
 179                                         /// bool operator >(E x, E y);
 180                                         /// bool operator <=(E x, E y);
 181                                         /// bool operator >=(E x, E y);
 182                                         ///
 183                                         case Binary.Operator.Equality:
 184                                         case Binary.Operator.Inequality:
 185                                         case Binary.Operator.LessThan:
 186                                         case Binary.Operator.GreaterThan:
 187                                         case Binary.Operator.LessThanOrEqual:
 188                                         case Binary.Operator.GreaterThanOrEqual:
 189                                                 return BinaryFold(ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
 190                                 }
 191                                 return null;
 192                         }
 193
 194                         switch (oper){
 195                         case Binary.Operator.BitwiseOr:
 196                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 197                                         return null;
 198
 199                                 if (left is IntConstant){
 200                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 201
 202                                         return new IntConstant (res, left.Location);
 203                                 }
 204                                 if (left is UIntConstant){
 205                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 206
 207                                         return new UIntConstant (res, left.Location);
 208                                 }
 209                                 if (left is LongConstant){
 210                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 211
 212                                         return new LongConstant (res, left.Location);
 213                                 }
 214                                 if (left is ULongConstant){
 215                                         ulong res = ((ULongConstant)left).Value |
 216                                                 ((ULongConstant)right).Value;
 217
 218                                         return new ULongConstant (res, left.Location);
 219                                 }
 220                                 break;
 221
 222                         case Binary.Operator.BitwiseAnd:
 223                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 224                                         return null;
 225
 226                                 ///
 227                                 /// int operator &(int x, int y);
 228                                 /// uint operator &(uint x, uint y);
 229                                 /// long operator &(long x, long y);
 230                                 /// ulong operator &(ulong x, ulong y);
 231                                 ///
 232                                 if (left is IntConstant){
 233                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 234                                         return new IntConstant (res, left.Location);
 235                                 }
 236                                 if (left is UIntConstant){
 237                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 238                                         return new UIntConstant (res, left.Location);
 239                                 }
 240                                 if (left is LongConstant){
 241                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 242                                         return new LongConstant (res, left.Location);
 243                                 }
 244                                 if (left is ULongConstant){
 245                                         ulong res = ((ULongConstant)left).Value &
 246                                                 ((ULongConstant)right).Value;
 247
 248                                         return new ULongConstant (res, left.Location);
 249                                 }
 250                                 break;
 251
 252                         case Binary.Operator.ExclusiveOr:
 253                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 254                                         return null;
 255
 256                                 if (left is IntConstant){
 257                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 258                                         return new IntConstant (res, left.Location);
 259                                 }
 260                                 if (left is UIntConstant){
 261                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 262
 263                                         return  new UIntConstant (res, left.Location);
 264                                 }
 265                                 if (left is LongConstant){
 266                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 267
 268                                         return new LongConstant (res, left.Location);
 269                                 }
 270                                 if (left is ULongConstant){
 271                                         ulong res = ((ULongConstant)left).Value ^
 272                                                 ((ULongConstant)right).Value;
 273
 274                                         return new ULongConstant (res, left.Location);
 275                                 }
 276                                 break;
 277
 278                         case Binary.Operator.Addition:
 279                                 if (lt == InternalType.Null)
 280                                         return right;
 281
 282                                 if (rt == InternalType.Null)
 283                                         return left;
 284
 285                                 //
 286                                 // If both sides are strings, then concatenate, if
 287                                 // one is a string, and the other is not, then defer
 288                                 // to runtime concatenation
 289                                 //
 290                                 if (lt == TypeManager.string_type || rt == TypeManager.string_type){
 291                                         if (lt == rt)
 292                                                 return new StringConstant ((string)left.GetValue () + (string)right.GetValue (),
 293                                                         left.Location);
 294
 295                                         return null;
 296                                 }
 297
 298                                 //
 299                                 // handle "E operator + (E x, U y)"
 300                                 // handle "E operator + (Y y, E x)"
 301                                 //
 302                                 EnumConstant lc = left as EnumConstant;
 303                                 EnumConstant rc = right as EnumConstant;
 304                                 if (lc != null || rc != null){
 305                                         if (lc == null) {
 306                                                 lc = rc;
 307                                                 lt = lc.Type;
 308                                                 right = left;
 309                                         }
 310
 311                                         // U has to be implicitly convetible to E.base
 312                                         right = right.ConvertImplicitly (ec, lc.Child.Type);
 313                                         if (right == null)
 314                                                 return null;
 315
 316                                         result = BinaryFold (ec, oper, lc.Child, right, loc);
 317                                         if (result == null)
 318                                                 return null;
 319
 320                                         result = result.Resolve (ec).TryReduce (ec, lt, loc);
 321                                         if (result == null)
 322                                                 return null;
 323
 324                                         return new EnumConstant (result, lt);
 325                                 }
 326
 327                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 328                                         return null;
 329
 330                                 try {
 331                                         if (left is DoubleConstant){
 332                                                 double res;
 333
 334                                                 if (ec.ConstantCheckState)
 335                                                         res = checked (((DoubleConstant) left).Value +
 336                                                                        ((DoubleConstant) right).Value);
 337                                                 else
 338                                                         res = unchecked (((DoubleConstant) left).Value +
 339                                                                          ((DoubleConstant) right).Value);
 340
 341                                                 return new DoubleConstant (res, left.Location);
 342                                         }
 343                                         if (left is FloatConstant){
 344                                                 float res;
 345
 346                                                 if (ec.ConstantCheckState)
 347                                                         res = checked (((FloatConstant) left).Value +
 348                                                                        ((FloatConstant) right).Value);
 349                                                 else
 350                                                         res = unchecked (((FloatConstant) left).Value +
 351                                                                          ((FloatConstant) right).Value);
 352
 353                                                 result = new FloatConstant (res, left.Location);
 354                                         } else if (left is ULongConstant){
 355                                                 ulong res;
 356
 357                                                 if (ec.ConstantCheckState)
 358                                                         res = checked (((ULongConstant) left).Value +
 359                                                                        ((ULongConstant) right).Value);
 360                                                 else
 361                                                         res = unchecked (((ULongConstant) left).Value +
 362                                                                          ((ULongConstant) right).Value);
 363
 364                                                 result = new ULongConstant (res, left.Location);
 365                                         } else if (left is LongConstant){
 366                                                 long res;
 367
 368                                                 if (ec.ConstantCheckState)
 369                                                         res = checked (((LongConstant) left).Value +
 370                                                                        ((LongConstant) right).Value);
 371                                                 else
 372                                                         res = unchecked (((LongConstant) left).Value +
 373                                                                          ((LongConstant) right).Value);
 374
 375                                                 result = new LongConstant (res, left.Location);
 376                                         } else if (left is UIntConstant){
 377                                                 uint res;
 378
 379                                                 if (ec.ConstantCheckState)
 380                                                         res = checked (((UIntConstant) left).Value +
 381                                                                        ((UIntConstant) right).Value);
 382                                                 else
 383                                                         res = unchecked (((UIntConstant) left).Value +
 384                                                                          ((UIntConstant) right).Value);
 385
 386                                                 result = new UIntConstant (res, left.Location);
 387                                         } else if (left is IntConstant){
 388                                                 int res;
 389
 390                                                 if (ec.ConstantCheckState)
 391                                                         res = checked (((IntConstant) left).Value +
 392                                                                        ((IntConstant) right).Value);
 393                                                 else
 394                                                         res = unchecked (((IntConstant) left).Value +
 395                                                                          ((IntConstant) right).Value);
 396
 397                                                 result = new IntConstant (res, left.Location);
 398                                         } else if (left is DecimalConstant) {
 399                                                 decimal res;
 400
 401                                                 if (ec.ConstantCheckState)
 402                                                         res = checked (((DecimalConstant) left).Value +
 403                                                                 ((DecimalConstant) right).Value);
 404                                                 else
 405                                                         res = unchecked (((DecimalConstant) left).Value +
 406                                                                 ((DecimalConstant) right).Value);
 407
 408                                                 result = new DecimalConstant (res, left.Location);
 409                                         }
 410                                 } catch (OverflowException){
 411                                         Error_CompileTimeOverflow (ec, loc);
 412                                 }
 413
 414                                 return result;
 415
 416                         case Binary.Operator.Subtraction:
 417                                 //
 418                                 // handle "E operator - (E x, U y)"
 419                                 // handle "E operator - (Y y, E x)"
 420                                 //
 421                                 lc = left as EnumConstant;
 422                                 rc = right as EnumConstant;
 423                                 if (lc != null || rc != null){
 424                                         if (lc == null) {
 425                                                 lc = rc;
 426                                                 lt = lc.Type;
 427                                                 right = left;
 428                                         }
 429
 430                                         // U has to be implicitly convetible to E.base
 431                                         right = right.ConvertImplicitly (ec, lc.Child.Type);
 432                                         if (right == null)
 433                                                 return null;
 434
 435                                         result = BinaryFold (ec, oper, lc.Child, right, loc);
 436                                         if (result == null)
 437                                                 return null;
 438
 439                                         result = result.Resolve (ec).TryReduce (ec, lt, loc);
 440                                         if (result == null)
 441                                                 return null;
 442
 443                                         return new EnumConstant (result, lt);
 444                                 }
 445
 446                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 447                                         return null;
 448
 449                                 try {
 450                                         if (left is DoubleConstant){
 451                                                 double res;
 452
 453                                                 if (ec.ConstantCheckState)
 454                                                         res = checked (((DoubleConstant) left).Value -
 455                                                                        ((DoubleConstant) right).Value);
 456                                                 else
 457                                                         res = unchecked (((DoubleConstant) left).Value -
 458                                                                          ((DoubleConstant) right).Value);
 459
 460                                                 result = new DoubleConstant (res, left.Location);
 461                                         } else if (left is FloatConstant){
 462                                                 float res;
 463
 464                                                 if (ec.ConstantCheckState)
 465                                                         res = checked (((FloatConstant) left).Value -
 466                                                                        ((FloatConstant) right).Value);
 467                                                 else
 468                                                         res = unchecked (((FloatConstant) left).Value -
 469                                                                          ((FloatConstant) right).Value);
 470
 471                                                 result = new FloatConstant (res, left.Location);
 472                                         } else if (left is ULongConstant){
 473                                                 ulong res;
 474
 475                                                 if (ec.ConstantCheckState)
 476                                                         res = checked (((ULongConstant) left).Value -
 477                                                                        ((ULongConstant) right).Value);
 478                                                 else
 479                                                         res = unchecked (((ULongConstant) left).Value -
 480                                                                          ((ULongConstant) right).Value);
 481
 482                                                 result = new ULongConstant (res, left.Location);
 483                                         } else if (left is LongConstant){
 484                                                 long res;
 485
 486                                                 if (ec.ConstantCheckState)
 487                                                         res = checked (((LongConstant) left).Value -
 488                                                                        ((LongConstant) right).Value);
 489                                                 else
 490                                                         res = unchecked (((LongConstant) left).Value -
 491                                                                          ((LongConstant) right).Value);
 492
 493                                                 result = new LongConstant (res, left.Location);
 494                                         } else if (left is UIntConstant){
 495                                                 uint res;
 496
 497                                                 if (ec.ConstantCheckState)
 498                                                         res = checked (((UIntConstant) left).Value -
 499                                                                        ((UIntConstant) right).Value);
 500                                                 else
 501                                                         res = unchecked (((UIntConstant) left).Value -
 502                                                                          ((UIntConstant) right).Value);
 503
 504                                                 result = new UIntConstant (res, left.Location);
 505                                         } else if (left is IntConstant){
 506                                                 int res;
 507
 508                                                 if (ec.ConstantCheckState)
 509                                                         res = checked (((IntConstant) left).Value -
 510                                                                        ((IntConstant) right).Value);
 511                                                 else
 512                                                         res = unchecked (((IntConstant) left).Value -
 513                                                                          ((IntConstant) right).Value);
 514
 515                                                 result = new IntConstant (res, left.Location);
 516                                         } else if (left is DecimalConstant) {
 517                                                 decimal res;
 518
 519                                                 if (ec.ConstantCheckState)
 520                                                         res = checked (((DecimalConstant) left).Value -
 521                                                                 ((DecimalConstant) right).Value);
 522                                                 else
 523                                                         res = unchecked (((DecimalConstant) left).Value -
 524                                                                 ((DecimalConstant) right).Value);
 525
 526                                                 return new DecimalConstant (res, left.Location);
 527                                         } else {
 528                                                 throw new Exception ( "Unexepected subtraction input: " + left);
 529                                         }
 530                                 } catch (OverflowException){
 531                                         Error_CompileTimeOverflow (ec, loc);
 532                                 }
 533
 534                                 return result;
 535
 536                         case Binary.Operator.Multiply:
 537                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 538                                         return null;
 539
 540                                 try {
 541                                         if (left is DoubleConstant){
 542                                                 double res;
 543
 544                                                 if (ec.ConstantCheckState)
 545                                                         res = checked (((DoubleConstant) left).Value *
 546                                                                 ((DoubleConstant) right).Value);
 547                                                 else
 548                                                         res = unchecked (((DoubleConstant) left).Value *
 549                                                                 ((DoubleConstant) right).Value);
 550
 551                                                 return new DoubleConstant (res, left.Location);
 552                                         } else if (left is FloatConstant){
 553                                                 float res;
 554
 555                                                 if (ec.ConstantCheckState)
 556                                                         res = checked (((FloatConstant) left).Value *
 557                                                                 ((FloatConstant) right).Value);
 558                                                 else
 559                                                         res = unchecked (((FloatConstant) left).Value *
 560                                                                 ((FloatConstant) right).Value);
 561
 562                                                 return new FloatConstant (res, left.Location);
 563                                         } else if (left is ULongConstant){
 564                                                 ulong res;
 565
 566                                                 if (ec.ConstantCheckState)
 567                                                         res = checked (((ULongConstant) left).Value *
 568                                                                 ((ULongConstant) right).Value);
 569                                                 else
 570                                                         res = unchecked (((ULongConstant) left).Value *
 571                                                                 ((ULongConstant) right).Value);
 572
 573                                                 return new ULongConstant (res, left.Location);
 574                                         } else if (left is LongConstant){
 575                                                 long res;
 576
 577                                                 if (ec.ConstantCheckState)
 578                                                         res = checked (((LongConstant) left).Value *
 579                                                                 ((LongConstant) right).Value);
 580                                                 else
 581                                                         res = unchecked (((LongConstant) left).Value *
 582                                                                 ((LongConstant) right).Value);
 583
 584                                                 return new LongConstant (res, left.Location);
 585                                         } else if (left is UIntConstant){
 586                                                 uint res;
 587
 588                                                 if (ec.ConstantCheckState)
 589                                                         res = checked (((UIntConstant) left).Value *
 590                                                                 ((UIntConstant) right).Value);
 591                                                 else
 592                                                         res = unchecked (((UIntConstant) left).Value *
 593                                                                 ((UIntConstant) right).Value);
 594
 595                                                 return new UIntConstant (res, left.Location);
 596                                         } else if (left is IntConstant){
 597                                                 int res;
 598
 599                                                 if (ec.ConstantCheckState)
 600                                                         res = checked (((IntConstant) left).Value *
 601                                                                 ((IntConstant) right).Value);
 602                                                 else
 603                                                         res = unchecked (((IntConstant) left).Value *
 604                                                                 ((IntConstant) right).Value);
 605
 606                                                 return new IntConstant (res, left.Location);
 607                                         } else if (left is DecimalConstant) {
 608                                                 decimal res;
 609
 610                                                 if (ec.ConstantCheckState)
 611                                                         res = checked (((DecimalConstant) left).Value *
 612                                                                 ((DecimalConstant) right).Value);
 613                                                 else
 614                                                         res = unchecked (((DecimalConstant) left).Value *
 615                                                                 ((DecimalConstant) right).Value);
 616
 617                                                 return new DecimalConstant (res, left.Location);
 618                                         } else {
 619                                                 throw new Exception ( "Unexepected multiply input: " + left);
 620                                         }
 621                                 } catch (OverflowException){
 622                                         Error_CompileTimeOverflow (ec, loc);
 623                                 }
 624                                 break;
 625
 626                         case Binary.Operator.Division:
 627                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 628                                         return null;
 629
 630                                 try {
 631                                         if (left is DoubleConstant){
 632                                                 double res;
 633
 634                                                 if (ec.ConstantCheckState)
 635                                                         res = checked (((DoubleConstant) left).Value /
 636                                                                 ((DoubleConstant) right).Value);
 637                                                 else
 638                                                         res = unchecked (((DoubleConstant) left).Value /
 639                                                                 ((DoubleConstant) right).Value);
 640
 641                                                 return new DoubleConstant (res, left.Location);
 642                                         } else if (left is FloatConstant){
 643                                                 float res;
 644
 645                                                 if (ec.ConstantCheckState)
 646                                                         res = checked (((FloatConstant) left).Value /
 647                                                                 ((FloatConstant) right).Value);
 648                                                 else
 649                                                         res = unchecked (((FloatConstant) left).Value /
 650                                                                 ((FloatConstant) right).Value);
 651
 652                                                 return new FloatConstant (res, left.Location);
 653                                         } else if (left is ULongConstant){
 654                                                 ulong res;
 655
 656                                                 if (ec.ConstantCheckState)
 657                                                         res = checked (((ULongConstant) left).Value /
 658                                                                 ((ULongConstant) right).Value);
 659                                                 else
 660                                                         res = unchecked (((ULongConstant) left).Value /
 661                                                                 ((ULongConstant) right).Value);
 662
 663                                                 return new ULongConstant (res, left.Location);
 664                                         } else if (left is LongConstant){
 665                                                 long res;
 666
 667                                                 if (ec.ConstantCheckState)
 668                                                         res = checked (((LongConstant) left).Value /
 669                                                                 ((LongConstant) right).Value);
 670                                                 else
 671                                                         res = unchecked (((LongConstant) left).Value /
 672                                                                 ((LongConstant) right).Value);
 673
 674                                                 return new LongConstant (res, left.Location);
 675                                         } else if (left is UIntConstant){
 676                                                 uint res;
 677
 678                                                 if (ec.ConstantCheckState)
 679                                                         res = checked (((UIntConstant) left).Value /
 680                                                                 ((UIntConstant) right).Value);
 681                                                 else
 682                                                         res = unchecked (((UIntConstant) left).Value /
 683                                                                 ((UIntConstant) right).Value);
 684
 685                                                 return new UIntConstant (res, left.Location);
 686                                         } else if (left is IntConstant){
 687                                                 int res;
 688
 689                                                 if (ec.ConstantCheckState)
 690                                                         res = checked (((IntConstant) left).Value /
 691                                                                 ((IntConstant) right).Value);
 692                                                 else
 693                                                         res = unchecked (((IntConstant) left).Value /
 694                                                                 ((IntConstant) right).Value);
 695
 696                                                 return new IntConstant (res, left.Location);
 697                                         } else if (left is DecimalConstant) {
 698                                                 decimal res;
 699
 700                                                 if (ec.ConstantCheckState)
 701                                                         res = checked (((DecimalConstant) left).Value /
 702                                                                 ((DecimalConstant) right).Value);
 703                                                 else
 704                                                         res = unchecked (((DecimalConstant) left).Value /
 705                                                                 ((DecimalConstant) right).Value);
 706
 707                                                 return new DecimalConstant (res, left.Location);
 708                                         } else {
 709                                                 throw new Exception ( "Unexepected division input: " + left);
 710                                         }
 711                                 } catch (OverflowException){
 712                                         Error_CompileTimeOverflow (ec, loc);
 713
 714                                 } catch (DivideByZeroException) {
 715                                         ec.Report.Error (20, loc, "Division by constant zero");
 716                                 }
 717
 718                                 break;
 719
 720                         case Binary.Operator.Modulus:
 721                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 722                                         return null;
 723
 724                                 try {
 725                                         if (left is DoubleConstant){
 726                                                 double res;
 727
 728                                                 if (ec.ConstantCheckState)
 729                                                         res = checked (((DoubleConstant) left).Value %
 730                                                                        ((DoubleConstant) right).Value);
 731                                                 else
 732                                                         res = unchecked (((DoubleConstant) left).Value %
 733                                                                          ((DoubleConstant) right).Value);
 734
 735                                                 return new DoubleConstant (res, left.Location);
 736                                         } else if (left is FloatConstant){
 737                                                 float res;
 738
 739                                                 if (ec.ConstantCheckState)
 740                                                         res = checked (((FloatConstant) left).Value %
 741                                                                        ((FloatConstant) right).Value);
 742                                                 else
 743                                                         res = unchecked (((FloatConstant) left).Value %
 744                                                                          ((FloatConstant) right).Value);
 745
 746                                                 return new FloatConstant (res, left.Location);
 747                                         } else if (left is ULongConstant){
 748                                                 ulong res;
 749
 750                                                 if (ec.ConstantCheckState)
 751                                                         res = checked (((ULongConstant) left).Value %
 752                                                                        ((ULongConstant) right).Value);
 753                                                 else
 754                                                         res = unchecked (((ULongConstant) left).Value %
 755                                                                          ((ULongConstant) right).Value);
 756
 757                                                 return new ULongConstant (res, left.Location);
 758                                         } else if (left is LongConstant){
 759                                                 long res;
 760
 761                                                 if (ec.ConstantCheckState)
 762                                                         res = checked (((LongConstant) left).Value %
 763                                                                        ((LongConstant) right).Value);
 764                                                 else
 765                                                         res = unchecked (((LongConstant) left).Value %
 766                                                                          ((LongConstant) right).Value);
 767
 768                                                 return new LongConstant (res, left.Location);
 769                                         } else if (left is UIntConstant){
 770                                                 uint res;
 771
 772                                                 if (ec.ConstantCheckState)
 773                                                         res = checked (((UIntConstant) left).Value %
 774                                                                        ((UIntConstant) right).Value);
 775                                                 else
 776                                                         res = unchecked (((UIntConstant) left).Value %
 777                                                                          ((UIntConstant) right).Value);
 778
 779                                                 return new UIntConstant (res, left.Location);
 780                                         } else if (left is IntConstant){
 781                                                 int res;
 782
 783                                                 if (ec.ConstantCheckState)
 784                                                         res = checked (((IntConstant) left).Value %
 785                                                                        ((IntConstant) right).Value);
 786                                                 else
 787                                                         res = unchecked (((IntConstant) left).Value %
 788                                                                          ((IntConstant) right).Value);
 789
 790                                                 return new IntConstant (res, left.Location);
 791                                         } else {
 792                                                 throw new Exception ( "Unexepected modulus input: " + left);
 793                                         }
 794                                 } catch (DivideByZeroException){
 795                                         ec.Report.Error (20, loc, "Division by constant zero");
 796                                 } catch (OverflowException){
 797                                         Error_CompileTimeOverflow (ec, loc);
 798                                 }
 799                                 break;
 800
 801                                 //
 802                                 // There is no overflow checking on left shift
 803                                 //
 804                         case Binary.Operator.LeftShift:
 805                                 IntConstant ic = right.ConvertImplicitly (ec, TypeManager.int32_type) as IntConstant;
 806                                 if (ic == null){
 807                                         Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc);
 808                                         return null;
 809                                 }
 810
 811                                 int lshift_val = ic.Value;
 812                                 if (left.Type == TypeManager.uint64_type)
 813                                         return new ULongConstant (((ULongConstant)left).Value << lshift_val, left.Location);
 814                                 if (left.Type == TypeManager.int64_type)
 815                                         return new LongConstant (((LongConstant)left).Value << lshift_val, left.Location);
 816                                 if (left.Type == TypeManager.uint32_type)
 817                                         return new UIntConstant (((UIntConstant)left).Value << lshift_val, left.Location);
 818
 819                                 left = left.ConvertImplicitly (ec, TypeManager.int32_type);
 820                                 if (left.Type == TypeManager.int32_type)
 821                                         return new IntConstant (((IntConstant)left).Value << lshift_val, left.Location);
 822
 823                                 Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc);
 824                                 break;
 825
 826                                 //
 827                                 // There is no overflow checking on right shift
 828                                 //
 829                         case Binary.Operator.RightShift:
 830                                 IntConstant sic = right.ConvertImplicitly (ec, TypeManager.int32_type) as IntConstant;
 831                                 if (sic == null){
 832                                         Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc); ;
 833                                         return null;
 834                                 }
 835                                 int rshift_val = sic.Value;
 836                                 if (left.Type == TypeManager.uint64_type)
 837                                         return new ULongConstant (((ULongConstant)left).Value >> rshift_val, left.Location);
 838                                 if (left.Type == TypeManager.int64_type)
 839                                         return new LongConstant (((LongConstant)left).Value >> rshift_val, left.Location);
 840                                 if (left.Type == TypeManager.uint32_type)
 841                                         return new UIntConstant (((UIntConstant)left).Value >> rshift_val, left.Location);
 842
 843                                 left = left.ConvertImplicitly (ec, TypeManager.int32_type);
 844                                 if (left.Type == TypeManager.int32_type)
 845                                         return new IntConstant (((IntConstant)left).Value >> rshift_val, left.Location);
 846
 847                                 Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc);
 848                                 break;
 849
 850                         case Binary.Operator.Equality:
 851                                 if (TypeManager.IsReferenceType (lt) && TypeManager.IsReferenceType (lt)) {
 852                                         if (left.IsNull || right.IsNull) {
 853                                                 return ReducedExpression.Create (
 854                                                         new BoolConstant (left.IsNull == right.IsNull, left.Location).Resolve (ec),
 855                                                         new Binary (oper, left, right, loc));
 856                                         }
 857
 858                                         if (left is StringConstant && right is StringConstant)
 859                                                 return new BoolConstant (
 860                                                         ((StringConstant) left).Value == ((StringConstant) right).Value, left.Location);
 861
 862                                         return null;
 863                                 }
 864
 865                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 866                                         return null;
 867
 868                                 bool_res = false;
 869                                 if (left is DoubleConstant)
 870                                         bool_res = ((DoubleConstant) left).Value ==
 871                                                 ((DoubleConstant) right).Value;
 872                                 else if (left is FloatConstant)
 873                                         bool_res = ((FloatConstant) left).Value ==
 874                                                 ((FloatConstant) right).Value;
 875                                 else if (left is ULongConstant)
 876                                         bool_res = ((ULongConstant) left).Value ==
 877                                                 ((ULongConstant) right).Value;
 878                                 else if (left is LongConstant)
 879                                         bool_res = ((LongConstant) left).Value ==
 880                                                 ((LongConstant) right).Value;
 881                                 else if (left is UIntConstant)
 882                                         bool_res = ((UIntConstant) left).Value ==
 883                                                 ((UIntConstant) right).Value;
 884                                 else if (left is IntConstant)
 885                                         bool_res = ((IntConstant) left).Value ==
 886                                                 ((IntConstant) right).Value;
 887                                 else
 888                                         return null;
 889
 890                                 return new BoolConstant (bool_res, left.Location);
 891
 892                         case Binary.Operator.Inequality:
 893                                 if (TypeManager.IsReferenceType (lt) && TypeManager.IsReferenceType (lt)) {
 894                                         if (left.IsNull || right.IsNull) {
 895                                                 return ReducedExpression.Create (
 896                                                         new BoolConstant (left.IsNull != right.IsNull, left.Location).Resolve (ec),
 897                                                         new Binary (oper, left, right, loc));
 898                                         }
 899
 900                                         if (left is StringConstant && right is StringConstant)
 901                                                 return new BoolConstant (
 902                                                         ((StringConstant) left).Value != ((StringConstant) right).Value, left.Location);
 903
 904                                         return null;
 905                                 }
 906
 907                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 908                                         return null;
 909
 910                                 bool_res = false;
 911                                 if (left is DoubleConstant)
 912                                         bool_res = ((DoubleConstant) left).Value !=
 913                                                 ((DoubleConstant) right).Value;
 914                                 else if (left is FloatConstant)
 915                                         bool_res = ((FloatConstant) left).Value !=
 916                                                 ((FloatConstant) right).Value;
 917                                 else if (left is ULongConstant)
 918                                         bool_res = ((ULongConstant) left).Value !=
 919                                                 ((ULongConstant) right).Value;
 920                                 else if (left is LongConstant)
 921                                         bool_res = ((LongConstant) left).Value !=
 922                                                 ((LongConstant) right).Value;
 923                                 else if (left is UIntConstant)
 924                                         bool_res = ((UIntConstant) left).Value !=
 925                                                 ((UIntConstant) right).Value;
 926                                 else if (left is IntConstant)
 927                                         bool_res = ((IntConstant) left).Value !=
 928                                                 ((IntConstant) right).Value;
 929                                 else
 930                                         return null;
 931
 932                                 return new BoolConstant (bool_res, left.Location);
 933
 934                         case Binary.Operator.LessThan:
 935                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 936                                         return null;
 937
 938                                 bool_res = false;
 939                                 if (left is DoubleConstant)
 940                                         bool_res = ((DoubleConstant) left).Value <
 941                                                 ((DoubleConstant) right).Value;
 942                                 else if (left is FloatConstant)
 943                                         bool_res = ((FloatConstant) left).Value <
 944                                                 ((FloatConstant) right).Value;
 945                                 else if (left is ULongConstant)
 946                                         bool_res = ((ULongConstant) left).Value <
 947                                                 ((ULongConstant) right).Value;
 948                                 else if (left is LongConstant)
 949                                         bool_res = ((LongConstant) left).Value <
 950                                                 ((LongConstant) right).Value;
 951                                 else if (left is UIntConstant)
 952                                         bool_res = ((UIntConstant) left).Value <
 953                                                 ((UIntConstant) right).Value;
 954                                 else if (left is IntConstant)
 955                                         bool_res = ((IntConstant) left).Value <
 956                                                 ((IntConstant) right).Value;
 957                                 else
 958                                         return null;
 959
 960                                 return new BoolConstant (bool_res, left.Location);
 961
 962                         case Binary.Operator.GreaterThan:
 963                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 964                                         return null;
 965
 966                                 bool_res = false;
 967                                 if (left is DoubleConstant)
 968                                         bool_res = ((DoubleConstant) left).Value >
 969                                                 ((DoubleConstant) right).Value;
 970                                 else if (left is FloatConstant)
 971                                         bool_res = ((FloatConstant) left).Value >
 972                                                 ((FloatConstant) right).Value;
 973                                 else if (left is ULongConstant)
 974                                         bool_res = ((ULongConstant) left).Value >
 975                                                 ((ULongConstant) right).Value;
 976                                 else if (left is LongConstant)
 977                                         bool_res = ((LongConstant) left).Value >
 978                                                 ((LongConstant) right).Value;
 979                                 else if (left is UIntConstant)
 980                                         bool_res = ((UIntConstant) left).Value >
 981                                                 ((UIntConstant) right).Value;
 982                                 else if (left is IntConstant)
 983                                         bool_res = ((IntConstant) left).Value >
 984                                                 ((IntConstant) right).Value;
 985                                 else
 986                                         return null;
 987
 988                                 return new BoolConstant (bool_res, left.Location);
 989
 990                         case Binary.Operator.GreaterThanOrEqual:
 991                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 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, left.Location);
1017
1018                         case Binary.Operator.LessThanOrEqual:
1019                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
1020                                         return null;
1021
1022                                 bool_res = false;
1023                                 if (left is DoubleConstant)
1024                                         bool_res = ((DoubleConstant) left).Value <=
1025                                                 ((DoubleConstant) right).Value;
1026                                 else if (left is FloatConstant)
1027                                         bool_res = ((FloatConstant) left).Value <=
1028                                                 ((FloatConstant) right).Value;
1029                                 else if (left is ULongConstant)
1030                                         bool_res = ((ULongConstant) left).Value <=
1031                                                 ((ULongConstant) right).Value;
1032                                 else if (left is LongConstant)
1033                                         bool_res = ((LongConstant) left).Value <=
1034                                                 ((LongConstant) right).Value;
1035                                 else if (left is UIntConstant)
1036                                         bool_res = ((UIntConstant) left).Value <=
1037                                                 ((UIntConstant) right).Value;
1038                                 else if (left is IntConstant)
1039                                         bool_res = ((IntConstant) left).Value <=
1040                                                 ((IntConstant) right).Value;
1041                                 else
1042                                         return null;
1043
1044                                 return new BoolConstant (bool_res, left.Location);
1045                         }
1046
1047                         return null;
1048                 }
1049         }
1050 }