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                 public static readonly 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 deposits 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                 // TODO: BinaryFold should be called as an optimization step only,
  29                 // error checking here is weak
  30                 //
  31                 static bool DoBinaryNumericPromotions (ResolveContext rc, ref Constant left, ref Constant right)
  32                 {
  33                         Type ltype = left.Type;
  34                         Type rtype = right.Type;
  35
  36                         foreach (Type t in binary_promotions) {
  37                                 if (t == ltype)
  38                                         return t == rtype || ConvertPromotion (rc, ref right, ref left, t);
  39
  40                                 if (t == rtype)
  41                                         return t == ltype || ConvertPromotion (rc, ref left, ref right, t);
  42                         }
  43
  44                         left = left.ConvertImplicitly (rc, TypeManager.int32_type);
  45                         right = right.ConvertImplicitly (rc, TypeManager.int32_type);
  46                         return left != null && right != null;
  47                 }
  48
  49                 static bool ConvertPromotion (ResolveContext rc, ref Constant prim, ref Constant second, Type type)
  50                 {
  51                         Constant c = prim.ConvertImplicitly (rc, type);
  52                         if (c != null) {
  53                                 prim = c;
  54                                 return true;
  55                         }
  56
  57                         if (type == TypeManager.uint32_type) {
  58                                 type = TypeManager.int64_type;
  59                                 prim = prim.ConvertImplicitly (rc, type);
  60                                 second = second.ConvertImplicitly (rc, type);
  61                                 return prim != null && second != null;
  62                         }
  63
  64                         return false;
  65                 }
  66
  67                 internal static void Error_CompileTimeOverflow (ResolveContext rc, Location loc)
  68                 {
  69                         rc.Report.Error (220, loc, "The operation overflows at compile time in checked mode");
  70                 }
  71
  72                 /// <summary>
  73                 ///   Constant expression folder for binary operations.
  74                 ///
  75                 ///   Returns null if the expression can not be folded.
  76                 /// </summary>
  77                 static public Constant BinaryFold (ResolveContext ec, Binary.Operator oper,
  78                                                      Constant left, Constant right, Location loc)
  79                 {
  80                         Constant result = null;
  81
  82                         if (left is EmptyConstantCast)
  83                                 return BinaryFold (ec, oper, ((EmptyConstantCast)left).child, right, loc);
  84
  85                         if (left is SideEffectConstant) {
  86                                 result = BinaryFold (ec, oper, ((SideEffectConstant) left).value, right, loc);
  87                                 if (result == null)
  88                                         return null;
  89                                 return new SideEffectConstant (result, left, loc);
  90                         }
  91
  92                         if (right is EmptyConstantCast)
  93                                 return BinaryFold (ec, oper, left, ((EmptyConstantCast)right).child, loc);
  94
  95                         if (right is SideEffectConstant) {
  96                                 result = BinaryFold (ec, oper, left, ((SideEffectConstant) right).value, loc);
  97                                 if (result == null)
  98                                         return null;
  99                                 return new SideEffectConstant (result, right, loc);
 100                         }
 101
 102                         Type lt = left.Type;
 103                         Type rt = right.Type;
 104                         bool bool_res;
 105
 106                         if (lt == TypeManager.bool_type && lt == rt) {
 107                                 bool lv = (bool) left.GetValue ();
 108                                 bool rv = (bool) right.GetValue ();
 109                                 switch (oper) {
 110                                 case Binary.Operator.BitwiseAnd:
 111                                 case Binary.Operator.LogicalAnd:
 112                                         return new BoolConstant (lv && rv, left.Location);
 113                                 case Binary.Operator.BitwiseOr:
 114                                 case Binary.Operator.LogicalOr:
 115                                         return new BoolConstant (lv || rv, left.Location);
 116                                 case Binary.Operator.ExclusiveOr:
 117                                         return new BoolConstant (lv ^ rv, left.Location);
 118                                 case Binary.Operator.Equality:
 119                                         return new BoolConstant (lv == rv, left.Location);
 120                                 case Binary.Operator.Inequality:
 121                                         return new BoolConstant (lv != rv, left.Location);
 122                                 }
 123                                 return null;
 124                         }
 125
 126                         //
 127                         // During an enum evaluation, none of the rules are valid
 128                         // Not sure whether it is bug in csc or in documentation
 129                         //
 130                         if (ec.HasSet (ResolveContext.Options.EnumScope)){
 131                                 if (left is EnumConstant)
 132                                         left = ((EnumConstant) left).Child;
 133
 134                                 if (right is EnumConstant)
 135                                         right = ((EnumConstant) right).Child;
 136                         } else if (left is EnumConstant && rt == lt) {
 137                                 switch (oper){
 138                                         ///
 139                                         /// E operator |(E x, E y);
 140                                         /// E operator &(E x, E y);
 141                                         /// E operator ^(E x, E y);
 142                                         ///
 143                                         case Binary.Operator.BitwiseOr:
 144                                         case Binary.Operator.BitwiseAnd:
 145                                         case Binary.Operator.ExclusiveOr:
 146                                                 result = BinaryFold (ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
 147                                                 if (result != null)
 148                                                         result = result.Resolve (ec).TryReduce (ec, lt, loc);
 149                                                 return result;
 150
 151                                         ///
 152                                         /// U operator -(E x, E y);
 153                                         ///
 154                                         case Binary.Operator.Subtraction:
 155                                                 result = BinaryFold (ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
 156                                                 if (result != null)
 157                                                         result = result.Resolve (ec).TryReduce (ec, ((EnumConstant)left).Child.Type, loc);
 158                                                 return result;
 159
 160                                         ///
 161                                         /// bool operator ==(E x, E y);
 162                                         /// bool operator !=(E x, E y);
 163                                         /// bool operator <(E x, E y);
 164                                         /// bool operator >(E x, E y);
 165                                         /// bool operator <=(E x, E y);
 166                                         /// bool operator >=(E x, E y);
 167                                         ///
 168                                         case Binary.Operator.Equality:
 169                                         case Binary.Operator.Inequality:
 170                                         case Binary.Operator.LessThan:
 171                                         case Binary.Operator.GreaterThan:
 172                                         case Binary.Operator.LessThanOrEqual:
 173                                         case Binary.Operator.GreaterThanOrEqual:
 174                                                 return BinaryFold(ec, oper, ((EnumConstant)left).Child, ((EnumConstant)right).Child, loc);
 175                                 }
 176                                 return null;
 177                         }
 178
 179                         switch (oper){
 180                         case Binary.Operator.BitwiseOr:
 181                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 182                                         return null;
 183
 184                                 if (left is IntConstant){
 185                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 186
 187                                         return new IntConstant (res, left.Location);
 188                                 }
 189                                 if (left is UIntConstant){
 190                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 191
 192                                         return new UIntConstant (res, left.Location);
 193                                 }
 194                                 if (left is LongConstant){
 195                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 196
 197                                         return new LongConstant (res, left.Location);
 198                                 }
 199                                 if (left is ULongConstant){
 200                                         ulong res = ((ULongConstant)left).Value |
 201                                                 ((ULongConstant)right).Value;
 202
 203                                         return new ULongConstant (res, left.Location);
 204                                 }
 205                                 break;
 206
 207                         case Binary.Operator.BitwiseAnd:
 208                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 209                                         return null;
 210
 211                                 ///
 212                                 /// int operator &(int x, int y);
 213                                 /// uint operator &(uint x, uint y);
 214                                 /// long operator &(long x, long y);
 215                                 /// ulong operator &(ulong x, ulong y);
 216                                 ///
 217                                 if (left is IntConstant){
 218                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 219                                         return new IntConstant (res, left.Location);
 220                                 }
 221                                 if (left is UIntConstant){
 222                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 223                                         return new UIntConstant (res, left.Location);
 224                                 }
 225                                 if (left is LongConstant){
 226                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 227                                         return new LongConstant (res, left.Location);
 228                                 }
 229                                 if (left is ULongConstant){
 230                                         ulong res = ((ULongConstant)left).Value &
 231                                                 ((ULongConstant)right).Value;
 232
 233                                         return new ULongConstant (res, left.Location);
 234                                 }
 235                                 break;
 236
 237                         case Binary.Operator.ExclusiveOr:
 238                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 239                                         return null;
 240
 241                                 if (left is IntConstant){
 242                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 243                                         return new IntConstant (res, left.Location);
 244                                 }
 245                                 if (left is UIntConstant){
 246                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 247
 248                                         return  new UIntConstant (res, left.Location);
 249                                 }
 250                                 if (left is LongConstant){
 251                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 252
 253                                         return new LongConstant (res, left.Location);
 254                                 }
 255                                 if (left is ULongConstant){
 256                                         ulong res = ((ULongConstant)left).Value ^
 257                                                 ((ULongConstant)right).Value;
 258
 259                                         return new ULongConstant (res, left.Location);
 260                                 }
 261                                 break;
 262
 263                         case Binary.Operator.Addition:
 264                                 if (lt == TypeManager.null_type)
 265                                         return right;
 266
 267                                 if (rt == TypeManager.null_type)
 268                                         return left;
 269
 270                                 //
 271                                 // If both sides are strings, then concatenate, if
 272                                 // one is a string, and the other is not, then defer
 273                                 // to runtime concatenation
 274                                 //
 275                                 if (lt == TypeManager.string_type || rt == TypeManager.string_type){
 276                                         if (lt == rt)
 277                                                 return new StringConstant ((string)left.GetValue () + (string)right.GetValue (),
 278                                                         left.Location);
 279
 280                                         return null;
 281                                 }
 282
 283                                 //
 284                                 // handle "E operator + (E x, U y)"
 285                                 // handle "E operator + (Y y, E x)"
 286                                 //
 287                                 EnumConstant lc = left as EnumConstant;
 288                                 EnumConstant rc = right as EnumConstant;
 289                                 if (lc != null || rc != null){
 290                                         if (lc == null) {
 291                                                 lc = rc;
 292                                                 lt = lc.Type;
 293                                                 right = left;
 294                                         }
 295
 296                                         // U has to be implicitly convetible to E.base
 297                                         right = right.ConvertImplicitly (ec, lc.Child.Type);
 298                                         if (right == null)
 299                                                 return null;
 300
 301                                         result = BinaryFold (ec, oper, lc.Child, right, loc);
 302                                         if (result == null)
 303                                                 return null;
 304
 305                                         result = result.Resolve (ec).TryReduce (ec, lt, loc);
 306                                         if (result == null)
 307                                                 return null;
 308
 309                                         return new EnumConstant (result, lt);
 310                                 }
 311
 312                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 313                                         return null;
 314
 315                                 try {
 316                                         if (left is DoubleConstant){
 317                                                 double res;
 318
 319                                                 if (ec.ConstantCheckState)
 320                                                         res = checked (((DoubleConstant) left).Value +
 321                                                                        ((DoubleConstant) right).Value);
 322                                                 else
 323                                                         res = unchecked (((DoubleConstant) left).Value +
 324                                                                          ((DoubleConstant) right).Value);
 325
 326                                                 return new DoubleConstant (res, left.Location);
 327                                         }
 328                                         if (left is FloatConstant){
 329                                                 float res;
 330
 331                                                 if (ec.ConstantCheckState)
 332                                                         res = checked (((FloatConstant) left).Value +
 333                                                                        ((FloatConstant) right).Value);
 334                                                 else
 335                                                         res = unchecked (((FloatConstant) left).Value +
 336                                                                          ((FloatConstant) right).Value);
 337
 338                                                 result = new FloatConstant (res, left.Location);
 339                                         } else if (left is ULongConstant){
 340                                                 ulong res;
 341
 342                                                 if (ec.ConstantCheckState)
 343                                                         res = checked (((ULongConstant) left).Value +
 344                                                                        ((ULongConstant) right).Value);
 345                                                 else
 346                                                         res = unchecked (((ULongConstant) left).Value +
 347                                                                          ((ULongConstant) right).Value);
 348
 349                                                 result = new ULongConstant (res, left.Location);
 350                                         } else if (left is LongConstant){
 351                                                 long res;
 352
 353                                                 if (ec.ConstantCheckState)
 354                                                         res = checked (((LongConstant) left).Value +
 355                                                                        ((LongConstant) right).Value);
 356                                                 else
 357                                                         res = unchecked (((LongConstant) left).Value +
 358                                                                          ((LongConstant) right).Value);
 359
 360                                                 result = new LongConstant (res, left.Location);
 361                                         } else if (left is UIntConstant){
 362                                                 uint res;
 363
 364                                                 if (ec.ConstantCheckState)
 365                                                         res = checked (((UIntConstant) left).Value +
 366                                                                        ((UIntConstant) right).Value);
 367                                                 else
 368                                                         res = unchecked (((UIntConstant) left).Value +
 369                                                                          ((UIntConstant) right).Value);
 370
 371                                                 result = new UIntConstant (res, left.Location);
 372                                         } else if (left is IntConstant){
 373                                                 int res;
 374
 375                                                 if (ec.ConstantCheckState)
 376                                                         res = checked (((IntConstant) left).Value +
 377                                                                        ((IntConstant) right).Value);
 378                                                 else
 379                                                         res = unchecked (((IntConstant) left).Value +
 380                                                                          ((IntConstant) right).Value);
 381
 382                                                 result = new IntConstant (res, left.Location);
 383                                         } else if (left is DecimalConstant) {
 384                                                 decimal res;
 385
 386                                                 if (ec.ConstantCheckState)
 387                                                         res = checked (((DecimalConstant) left).Value +
 388                                                                 ((DecimalConstant) right).Value);
 389                                                 else
 390                                                         res = unchecked (((DecimalConstant) left).Value +
 391                                                                 ((DecimalConstant) right).Value);
 392
 393                                                 result = new DecimalConstant (res, left.Location);
 394                                         }
 395                                 } catch (OverflowException){
 396                                         Error_CompileTimeOverflow (ec, loc);
 397                                 }
 398
 399                                 return result;
 400
 401                         case Binary.Operator.Subtraction:
 402                                 //
 403                                 // handle "E operator - (E x, U y)"
 404                                 // handle "E operator - (Y y, E x)"
 405                                 //
 406                                 lc = left as EnumConstant;
 407                                 rc = right as EnumConstant;
 408                                 if (lc != null || rc != null){
 409                                         if (lc == null) {
 410                                                 lc = rc;
 411                                                 lt = lc.Type;
 412                                                 right = left;
 413                                         }
 414
 415                                         // U has to be implicitly convetible to E.base
 416                                         right = right.ConvertImplicitly (ec, lc.Child.Type);
 417                                         if (right == null)
 418                                                 return null;
 419
 420                                         result = BinaryFold (ec, oper, lc.Child, right, loc);
 421                                         if (result == null)
 422                                                 return null;
 423
 424                                         result = result.Resolve (ec).TryReduce (ec, lt, loc);
 425                                         if (result == null)
 426                                                 return null;
 427
 428                                         return new EnumConstant (result, lt);
 429                                 }
 430
 431                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 432                                         return null;
 433
 434                                 try {
 435                                         if (left is DoubleConstant){
 436                                                 double res;
 437
 438                                                 if (ec.ConstantCheckState)
 439                                                         res = checked (((DoubleConstant) left).Value -
 440                                                                        ((DoubleConstant) right).Value);
 441                                                 else
 442                                                         res = unchecked (((DoubleConstant) left).Value -
 443                                                                          ((DoubleConstant) right).Value);
 444
 445                                                 result = new DoubleConstant (res, left.Location);
 446                                         } else if (left is FloatConstant){
 447                                                 float res;
 448
 449                                                 if (ec.ConstantCheckState)
 450                                                         res = checked (((FloatConstant) left).Value -
 451                                                                        ((FloatConstant) right).Value);
 452                                                 else
 453                                                         res = unchecked (((FloatConstant) left).Value -
 454                                                                          ((FloatConstant) right).Value);
 455
 456                                                 result = new FloatConstant (res, left.Location);
 457                                         } else if (left is ULongConstant){
 458                                                 ulong res;
 459
 460                                                 if (ec.ConstantCheckState)
 461                                                         res = checked (((ULongConstant) left).Value -
 462                                                                        ((ULongConstant) right).Value);
 463                                                 else
 464                                                         res = unchecked (((ULongConstant) left).Value -
 465                                                                          ((ULongConstant) right).Value);
 466
 467                                                 result = new ULongConstant (res, left.Location);
 468                                         } else if (left is LongConstant){
 469                                                 long res;
 470
 471                                                 if (ec.ConstantCheckState)
 472                                                         res = checked (((LongConstant) left).Value -
 473                                                                        ((LongConstant) right).Value);
 474                                                 else
 475                                                         res = unchecked (((LongConstant) left).Value -
 476                                                                          ((LongConstant) right).Value);
 477
 478                                                 result = new LongConstant (res, left.Location);
 479                                         } else if (left is UIntConstant){
 480                                                 uint res;
 481
 482                                                 if (ec.ConstantCheckState)
 483                                                         res = checked (((UIntConstant) left).Value -
 484                                                                        ((UIntConstant) right).Value);
 485                                                 else
 486                                                         res = unchecked (((UIntConstant) left).Value -
 487                                                                          ((UIntConstant) right).Value);
 488
 489                                                 result = new UIntConstant (res, left.Location);
 490                                         } else if (left is IntConstant){
 491                                                 int res;
 492
 493                                                 if (ec.ConstantCheckState)
 494                                                         res = checked (((IntConstant) left).Value -
 495                                                                        ((IntConstant) right).Value);
 496                                                 else
 497                                                         res = unchecked (((IntConstant) left).Value -
 498                                                                          ((IntConstant) right).Value);
 499
 500                                                 result = new IntConstant (res, left.Location);
 501                                         } else if (left is DecimalConstant) {
 502                                                 decimal res;
 503
 504                                                 if (ec.ConstantCheckState)
 505                                                         res = checked (((DecimalConstant) left).Value -
 506                                                                 ((DecimalConstant) right).Value);
 507                                                 else
 508                                                         res = unchecked (((DecimalConstant) left).Value -
 509                                                                 ((DecimalConstant) right).Value);
 510
 511                                                 return new DecimalConstant (res, left.Location);
 512                                         } else {
 513                                                 throw new Exception ( "Unexepected subtraction input: " + left);
 514                                         }
 515                                 } catch (OverflowException){
 516                                         Error_CompileTimeOverflow (ec, loc);
 517                                 }
 518
 519                                 return result;
 520
 521                         case Binary.Operator.Multiply:
 522                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 523                                         return null;
 524
 525                                 try {
 526                                         if (left is DoubleConstant){
 527                                                 double res;
 528
 529                                                 if (ec.ConstantCheckState)
 530                                                         res = checked (((DoubleConstant) left).Value *
 531                                                                 ((DoubleConstant) right).Value);
 532                                                 else
 533                                                         res = unchecked (((DoubleConstant) left).Value *
 534                                                                 ((DoubleConstant) right).Value);
 535
 536                                                 return new DoubleConstant (res, left.Location);
 537                                         } else if (left is FloatConstant){
 538                                                 float res;
 539
 540                                                 if (ec.ConstantCheckState)
 541                                                         res = checked (((FloatConstant) left).Value *
 542                                                                 ((FloatConstant) right).Value);
 543                                                 else
 544                                                         res = unchecked (((FloatConstant) left).Value *
 545                                                                 ((FloatConstant) right).Value);
 546
 547                                                 return new FloatConstant (res, left.Location);
 548                                         } else if (left is ULongConstant){
 549                                                 ulong res;
 550
 551                                                 if (ec.ConstantCheckState)
 552                                                         res = checked (((ULongConstant) left).Value *
 553                                                                 ((ULongConstant) right).Value);
 554                                                 else
 555                                                         res = unchecked (((ULongConstant) left).Value *
 556                                                                 ((ULongConstant) right).Value);
 557
 558                                                 return new ULongConstant (res, left.Location);
 559                                         } else if (left is LongConstant){
 560                                                 long res;
 561
 562                                                 if (ec.ConstantCheckState)
 563                                                         res = checked (((LongConstant) left).Value *
 564                                                                 ((LongConstant) right).Value);
 565                                                 else
 566                                                         res = unchecked (((LongConstant) left).Value *
 567                                                                 ((LongConstant) right).Value);
 568
 569                                                 return new LongConstant (res, left.Location);
 570                                         } else if (left is UIntConstant){
 571                                                 uint res;
 572
 573                                                 if (ec.ConstantCheckState)
 574                                                         res = checked (((UIntConstant) left).Value *
 575                                                                 ((UIntConstant) right).Value);
 576                                                 else
 577                                                         res = unchecked (((UIntConstant) left).Value *
 578                                                                 ((UIntConstant) right).Value);
 579
 580                                                 return new UIntConstant (res, left.Location);
 581                                         } else if (left is IntConstant){
 582                                                 int res;
 583
 584                                                 if (ec.ConstantCheckState)
 585                                                         res = checked (((IntConstant) left).Value *
 586                                                                 ((IntConstant) right).Value);
 587                                                 else
 588                                                         res = unchecked (((IntConstant) left).Value *
 589                                                                 ((IntConstant) right).Value);
 590
 591                                                 return new IntConstant (res, left.Location);
 592                                         } else if (left is DecimalConstant) {
 593                                                 decimal res;
 594
 595                                                 if (ec.ConstantCheckState)
 596                                                         res = checked (((DecimalConstant) left).Value *
 597                                                                 ((DecimalConstant) right).Value);
 598                                                 else
 599                                                         res = unchecked (((DecimalConstant) left).Value *
 600                                                                 ((DecimalConstant) right).Value);
 601
 602                                                 return new DecimalConstant (res, left.Location);
 603                                         } else {
 604                                                 throw new Exception ( "Unexepected multiply input: " + left);
 605                                         }
 606                                 } catch (OverflowException){
 607                                         Error_CompileTimeOverflow (ec, loc);
 608                                 }
 609                                 break;
 610
 611                         case Binary.Operator.Division:
 612                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 613                                         return null;
 614
 615                                 try {
 616                                         if (left is DoubleConstant){
 617                                                 double res;
 618
 619                                                 if (ec.ConstantCheckState)
 620                                                         res = checked (((DoubleConstant) left).Value /
 621                                                                 ((DoubleConstant) right).Value);
 622                                                 else
 623                                                         res = unchecked (((DoubleConstant) left).Value /
 624                                                                 ((DoubleConstant) right).Value);
 625
 626                                                 return new DoubleConstant (res, left.Location);
 627                                         } else if (left is FloatConstant){
 628                                                 float res;
 629
 630                                                 if (ec.ConstantCheckState)
 631                                                         res = checked (((FloatConstant) left).Value /
 632                                                                 ((FloatConstant) right).Value);
 633                                                 else
 634                                                         res = unchecked (((FloatConstant) left).Value /
 635                                                                 ((FloatConstant) right).Value);
 636
 637                                                 return new FloatConstant (res, left.Location);
 638                                         } else if (left is ULongConstant){
 639                                                 ulong res;
 640
 641                                                 if (ec.ConstantCheckState)
 642                                                         res = checked (((ULongConstant) left).Value /
 643                                                                 ((ULongConstant) right).Value);
 644                                                 else
 645                                                         res = unchecked (((ULongConstant) left).Value /
 646                                                                 ((ULongConstant) right).Value);
 647
 648                                                 return new ULongConstant (res, left.Location);
 649                                         } else if (left is LongConstant){
 650                                                 long res;
 651
 652                                                 if (ec.ConstantCheckState)
 653                                                         res = checked (((LongConstant) left).Value /
 654                                                                 ((LongConstant) right).Value);
 655                                                 else
 656                                                         res = unchecked (((LongConstant) left).Value /
 657                                                                 ((LongConstant) right).Value);
 658
 659                                                 return new LongConstant (res, left.Location);
 660                                         } else if (left is UIntConstant){
 661                                                 uint res;
 662
 663                                                 if (ec.ConstantCheckState)
 664                                                         res = checked (((UIntConstant) left).Value /
 665                                                                 ((UIntConstant) right).Value);
 666                                                 else
 667                                                         res = unchecked (((UIntConstant) left).Value /
 668                                                                 ((UIntConstant) right).Value);
 669
 670                                                 return new UIntConstant (res, left.Location);
 671                                         } else if (left is IntConstant){
 672                                                 int res;
 673
 674                                                 if (ec.ConstantCheckState)
 675                                                         res = checked (((IntConstant) left).Value /
 676                                                                 ((IntConstant) right).Value);
 677                                                 else
 678                                                         res = unchecked (((IntConstant) left).Value /
 679                                                                 ((IntConstant) right).Value);
 680
 681                                                 return new IntConstant (res, left.Location);
 682                                         } else if (left is DecimalConstant) {
 683                                                 decimal res;
 684
 685                                                 if (ec.ConstantCheckState)
 686                                                         res = checked (((DecimalConstant) left).Value /
 687                                                                 ((DecimalConstant) right).Value);
 688                                                 else
 689                                                         res = unchecked (((DecimalConstant) left).Value /
 690                                                                 ((DecimalConstant) right).Value);
 691
 692                                                 return new DecimalConstant (res, left.Location);
 693                                         } else {
 694                                                 throw new Exception ( "Unexepected division input: " + left);
 695                                         }
 696                                 } catch (OverflowException){
 697                                         Error_CompileTimeOverflow (ec, loc);
 698
 699                                 } catch (DivideByZeroException) {
 700                                         ec.Report.Error (20, loc, "Division by constant zero");
 701                                 }
 702
 703                                 break;
 704
 705                         case Binary.Operator.Modulus:
 706                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 707                                         return null;
 708
 709                                 try {
 710                                         if (left is DoubleConstant){
 711                                                 double res;
 712
 713                                                 if (ec.ConstantCheckState)
 714                                                         res = checked (((DoubleConstant) left).Value %
 715                                                                        ((DoubleConstant) right).Value);
 716                                                 else
 717                                                         res = unchecked (((DoubleConstant) left).Value %
 718                                                                          ((DoubleConstant) right).Value);
 719
 720                                                 return new DoubleConstant (res, left.Location);
 721                                         } else if (left is FloatConstant){
 722                                                 float res;
 723
 724                                                 if (ec.ConstantCheckState)
 725                                                         res = checked (((FloatConstant) left).Value %
 726                                                                        ((FloatConstant) right).Value);
 727                                                 else
 728                                                         res = unchecked (((FloatConstant) left).Value %
 729                                                                          ((FloatConstant) right).Value);
 730
 731                                                 return new FloatConstant (res, left.Location);
 732                                         } else if (left is ULongConstant){
 733                                                 ulong res;
 734
 735                                                 if (ec.ConstantCheckState)
 736                                                         res = checked (((ULongConstant) left).Value %
 737                                                                        ((ULongConstant) right).Value);
 738                                                 else
 739                                                         res = unchecked (((ULongConstant) left).Value %
 740                                                                          ((ULongConstant) right).Value);
 741
 742                                                 return new ULongConstant (res, left.Location);
 743                                         } else if (left is LongConstant){
 744                                                 long res;
 745
 746                                                 if (ec.ConstantCheckState)
 747                                                         res = checked (((LongConstant) left).Value %
 748                                                                        ((LongConstant) right).Value);
 749                                                 else
 750                                                         res = unchecked (((LongConstant) left).Value %
 751                                                                          ((LongConstant) right).Value);
 752
 753                                                 return new LongConstant (res, left.Location);
 754                                         } else if (left is UIntConstant){
 755                                                 uint res;
 756
 757                                                 if (ec.ConstantCheckState)
 758                                                         res = checked (((UIntConstant) left).Value %
 759                                                                        ((UIntConstant) right).Value);
 760                                                 else
 761                                                         res = unchecked (((UIntConstant) left).Value %
 762                                                                          ((UIntConstant) right).Value);
 763
 764                                                 return new UIntConstant (res, left.Location);
 765                                         } else if (left is IntConstant){
 766                                                 int res;
 767
 768                                                 if (ec.ConstantCheckState)
 769                                                         res = checked (((IntConstant) left).Value %
 770                                                                        ((IntConstant) right).Value);
 771                                                 else
 772                                                         res = unchecked (((IntConstant) left).Value %
 773                                                                          ((IntConstant) right).Value);
 774
 775                                                 return new IntConstant (res, left.Location);
 776                                         } else {
 777                                                 throw new Exception ( "Unexepected modulus input: " + left);
 778                                         }
 779                                 } catch (DivideByZeroException){
 780                                         ec.Report.Error (20, loc, "Division by constant zero");
 781                                 } catch (OverflowException){
 782                                         Error_CompileTimeOverflow (ec, loc);
 783                                 }
 784                                 break;
 785
 786                                 //
 787                                 // There is no overflow checking on left shift
 788                                 //
 789                         case Binary.Operator.LeftShift:
 790                                 IntConstant ic = right.ConvertImplicitly (ec, TypeManager.int32_type) as IntConstant;
 791                                 if (ic == null){
 792                                         Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc);
 793                                         return null;
 794                                 }
 795
 796                                 int lshift_val = ic.Value;
 797                                 if (left.Type == TypeManager.uint64_type)
 798                                         return new ULongConstant (((ULongConstant)left).Value << lshift_val, left.Location);
 799                                 if (left.Type == TypeManager.int64_type)
 800                                         return new LongConstant (((LongConstant)left).Value << lshift_val, left.Location);
 801                                 if (left.Type == TypeManager.uint32_type)
 802                                         return new UIntConstant (((UIntConstant)left).Value << lshift_val, left.Location);
 803
 804                                 left = left.ConvertImplicitly (ec, TypeManager.int32_type);
 805                                 if (left.Type == TypeManager.int32_type)
 806                                         return new IntConstant (((IntConstant)left).Value << lshift_val, left.Location);
 807
 808                                 Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc);
 809                                 break;
 810
 811                                 //
 812                                 // There is no overflow checking on right shift
 813                                 //
 814                         case Binary.Operator.RightShift:
 815                                 IntConstant sic = right.ConvertImplicitly (ec, TypeManager.int32_type) as IntConstant;
 816                                 if (sic == null){
 817                                         Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc); ;
 818                                         return null;
 819                                 }
 820                                 int rshift_val = sic.Value;
 821                                 if (left.Type == TypeManager.uint64_type)
 822                                         return new ULongConstant (((ULongConstant)left).Value >> rshift_val, left.Location);
 823                                 if (left.Type == TypeManager.int64_type)
 824                                         return new LongConstant (((LongConstant)left).Value >> rshift_val, left.Location);
 825                                 if (left.Type == TypeManager.uint32_type)
 826                                         return new UIntConstant (((UIntConstant)left).Value >> rshift_val, left.Location);
 827
 828                                 left = left.ConvertImplicitly (ec, TypeManager.int32_type);
 829                                 if (left.Type == TypeManager.int32_type)
 830                                         return new IntConstant (((IntConstant)left).Value >> rshift_val, left.Location);
 831
 832                                 Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc);
 833                                 break;
 834
 835                         case Binary.Operator.Equality:
 836                                 if (TypeManager.IsReferenceType (lt) && TypeManager.IsReferenceType (lt)) {
 837                                         if (left.IsNull || right.IsNull) {
 838                                                 return ReducedExpression.Create (
 839                                                         new BoolConstant (left.IsNull == right.IsNull, left.Location).Resolve (ec),
 840                                                         new Binary (oper, left, right, loc));
 841                                         }
 842
 843                                         if (left is StringConstant && right is StringConstant)
 844                                                 return new BoolConstant (
 845                                                         ((StringConstant) left).Value == ((StringConstant) right).Value, left.Location);
 846
 847                                         return null;
 848                                 }
 849
 850                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 851                                         return null;
 852
 853                                 bool_res = false;
 854                                 if (left is DoubleConstant)
 855                                         bool_res = ((DoubleConstant) left).Value ==
 856                                                 ((DoubleConstant) right).Value;
 857                                 else if (left is FloatConstant)
 858                                         bool_res = ((FloatConstant) left).Value ==
 859                                                 ((FloatConstant) right).Value;
 860                                 else if (left is ULongConstant)
 861                                         bool_res = ((ULongConstant) left).Value ==
 862                                                 ((ULongConstant) right).Value;
 863                                 else if (left is LongConstant)
 864                                         bool_res = ((LongConstant) left).Value ==
 865                                                 ((LongConstant) right).Value;
 866                                 else if (left is UIntConstant)
 867                                         bool_res = ((UIntConstant) left).Value ==
 868                                                 ((UIntConstant) right).Value;
 869                                 else if (left is IntConstant)
 870                                         bool_res = ((IntConstant) left).Value ==
 871                                                 ((IntConstant) right).Value;
 872                                 else
 873                                         return null;
 874
 875                                 return new BoolConstant (bool_res, left.Location);
 876
 877                         case Binary.Operator.Inequality:
 878                                 if (TypeManager.IsReferenceType (lt) && TypeManager.IsReferenceType (lt)) {
 879                                         if (left.IsNull || right.IsNull) {
 880                                                 return ReducedExpression.Create (
 881                                                         new BoolConstant (left.IsNull != right.IsNull, left.Location).Resolve (ec),
 882                                                         new Binary (oper, left, right, loc));
 883                                         }
 884
 885                                         if (left is StringConstant && right is StringConstant)
 886                                                 return new BoolConstant (
 887                                                         ((StringConstant) left).Value != ((StringConstant) right).Value, left.Location);
 888
 889                                         return null;
 890                                 }
 891
 892                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 893                                         return null;
 894
 895                                 bool_res = false;
 896                                 if (left is DoubleConstant)
 897                                         bool_res = ((DoubleConstant) left).Value !=
 898                                                 ((DoubleConstant) right).Value;
 899                                 else if (left is FloatConstant)
 900                                         bool_res = ((FloatConstant) left).Value !=
 901                                                 ((FloatConstant) right).Value;
 902                                 else if (left is ULongConstant)
 903                                         bool_res = ((ULongConstant) left).Value !=
 904                                                 ((ULongConstant) right).Value;
 905                                 else if (left is LongConstant)
 906                                         bool_res = ((LongConstant) left).Value !=
 907                                                 ((LongConstant) right).Value;
 908                                 else if (left is UIntConstant)
 909                                         bool_res = ((UIntConstant) left).Value !=
 910                                                 ((UIntConstant) right).Value;
 911                                 else if (left is IntConstant)
 912                                         bool_res = ((IntConstant) left).Value !=
 913                                                 ((IntConstant) right).Value;
 914                                 else
 915                                         return null;
 916
 917                                 return new BoolConstant (bool_res, left.Location);
 918
 919                         case Binary.Operator.LessThan:
 920                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 921                                         return null;
 922
 923                                 bool_res = false;
 924                                 if (left is DoubleConstant)
 925                                         bool_res = ((DoubleConstant) left).Value <
 926                                                 ((DoubleConstant) right).Value;
 927                                 else if (left is FloatConstant)
 928                                         bool_res = ((FloatConstant) left).Value <
 929                                                 ((FloatConstant) right).Value;
 930                                 else if (left is ULongConstant)
 931                                         bool_res = ((ULongConstant) left).Value <
 932                                                 ((ULongConstant) right).Value;
 933                                 else if (left is LongConstant)
 934                                         bool_res = ((LongConstant) left).Value <
 935                                                 ((LongConstant) right).Value;
 936                                 else if (left is UIntConstant)
 937                                         bool_res = ((UIntConstant) left).Value <
 938                                                 ((UIntConstant) right).Value;
 939                                 else if (left is IntConstant)
 940                                         bool_res = ((IntConstant) left).Value <
 941                                                 ((IntConstant) right).Value;
 942                                 else
 943                                         return null;
 944
 945                                 return new BoolConstant (bool_res, left.Location);
 946
 947                         case Binary.Operator.GreaterThan:
 948                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 949                                         return null;
 950
 951                                 bool_res = false;
 952                                 if (left is DoubleConstant)
 953                                         bool_res = ((DoubleConstant) left).Value >
 954                                                 ((DoubleConstant) right).Value;
 955                                 else if (left is FloatConstant)
 956                                         bool_res = ((FloatConstant) left).Value >
 957                                                 ((FloatConstant) right).Value;
 958                                 else if (left is ULongConstant)
 959                                         bool_res = ((ULongConstant) left).Value >
 960                                                 ((ULongConstant) right).Value;
 961                                 else if (left is LongConstant)
 962                                         bool_res = ((LongConstant) left).Value >
 963                                                 ((LongConstant) right).Value;
 964                                 else if (left is UIntConstant)
 965                                         bool_res = ((UIntConstant) left).Value >
 966                                                 ((UIntConstant) right).Value;
 967                                 else if (left is IntConstant)
 968                                         bool_res = ((IntConstant) left).Value >
 969                                                 ((IntConstant) right).Value;
 970                                 else
 971                                         return null;
 972
 973                                 return new BoolConstant (bool_res, left.Location);
 974
 975                         case Binary.Operator.GreaterThanOrEqual:
 976                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 977                                         return null;
 978
 979                                 bool_res = false;
 980                                 if (left is DoubleConstant)
 981                                         bool_res = ((DoubleConstant) left).Value >=
 982                                                 ((DoubleConstant) right).Value;
 983                                 else if (left is FloatConstant)
 984                                         bool_res = ((FloatConstant) left).Value >=
 985                                                 ((FloatConstant) right).Value;
 986                                 else if (left is ULongConstant)
 987                                         bool_res = ((ULongConstant) left).Value >=
 988                                                 ((ULongConstant) right).Value;
 989                                 else if (left is LongConstant)
 990                                         bool_res = ((LongConstant) left).Value >=
 991                                                 ((LongConstant) right).Value;
 992                                 else if (left is UIntConstant)
 993                                         bool_res = ((UIntConstant) left).Value >=
 994                                                 ((UIntConstant) right).Value;
 995                                 else if (left is IntConstant)
 996                                         bool_res = ((IntConstant) left).Value >=
 997                                                 ((IntConstant) right).Value;
 998                                 else
 999                                         return null;
1000
1001                                 return new BoolConstant (bool_res, left.Location);
1002
1003                         case Binary.Operator.LessThanOrEqual:
1004                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
1005                                         return null;
1006
1007                                 bool_res = false;
1008                                 if (left is DoubleConstant)
1009                                         bool_res = ((DoubleConstant) left).Value <=
1010                                                 ((DoubleConstant) right).Value;
1011                                 else if (left is FloatConstant)
1012                                         bool_res = ((FloatConstant) left).Value <=
1013                                                 ((FloatConstant) right).Value;
1014                                 else if (left is ULongConstant)
1015                                         bool_res = ((ULongConstant) left).Value <=
1016                                                 ((ULongConstant) right).Value;
1017                                 else if (left is LongConstant)
1018                                         bool_res = ((LongConstant) left).Value <=
1019                                                 ((LongConstant) right).Value;
1020                                 else if (left is UIntConstant)
1021                                         bool_res = ((UIntConstant) left).Value <=
1022                                                 ((UIntConstant) right).Value;
1023                                 else if (left is IntConstant)
1024                                         bool_res = ((IntConstant) left).Value <=
1025                                                 ((IntConstant) right).Value;
1026                                 else
1027                                         return null;
1028
1029                                 return new BoolConstant (bool_res, left.Location);
1030                         }
1031
1032                         return null;
1033                 }
1034         }
1035 }