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, EnumSpec.GetUnderlyingType (lt), 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                                 //
 197                                 // bool? operator &(bool? x, bool? y);
 198                                 //
 199                                 if ((lt == TypeManager.bool_type && right is NullLiteral) ||
 200                                         (rt == TypeManager.bool_type && left is NullLiteral)) {
 201                                         var b = new Nullable.LiftedBinaryOperator (oper, left, right, loc).Resolve (ec);
 202
 203                                         // false | null => null
 204                                         // null | false => null
 205                                         if ((right is NullLiteral && left.IsDefaultValue) || (left is NullLiteral && right.IsDefaultValue))
 206                                                 return Nullable.LiftedNull.CreateFromExpression (ec, b);
 207
 208                                         // true | null => true
 209                                         // null | true => true
 210                                         return ReducedExpression.Create (new BoolConstant (true, loc).Resolve (ec), b);
 211                                 }
 212
 213                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 214                                         return null;
 215
 216                                 if (left is IntConstant){
 217                                         int res = ((IntConstant) left).Value | ((IntConstant) right).Value;
 218
 219                                         return new IntConstant (res, left.Location);
 220                                 }
 221                                 if (left is UIntConstant){
 222                                         uint res = ((UIntConstant)left).Value | ((UIntConstant)right).Value;
 223
 224                                         return new UIntConstant (res, left.Location);
 225                                 }
 226                                 if (left is LongConstant){
 227                                         long res = ((LongConstant)left).Value | ((LongConstant)right).Value;
 228
 229                                         return new LongConstant (res, left.Location);
 230                                 }
 231                                 if (left is ULongConstant){
 232                                         ulong res = ((ULongConstant)left).Value |
 233                                                 ((ULongConstant)right).Value;
 234
 235                                         return new ULongConstant (res, left.Location);
 236                                 }
 237                                 break;
 238
 239                         case Binary.Operator.BitwiseAnd:
 240                                 //
 241                                 // bool? operator &(bool? x, bool? y);
 242                                 //
 243                                 if ((lt == TypeManager.bool_type && right is NullLiteral) ||
 244                                         (rt == TypeManager.bool_type && left is NullLiteral)) {
 245                                         var b = new Nullable.LiftedBinaryOperator (oper, left, right, loc).Resolve (ec);
 246
 247                                         // false & null => false
 248                                         // null & false => false
 249                                         if ((right is NullLiteral && left.IsDefaultValue) || (left is NullLiteral && right.IsDefaultValue))
 250                                                 return ReducedExpression.Create (new BoolConstant (false, loc).Resolve (ec), b);
 251
 252                                         // true & null => null
 253                                         // null & true => null
 254                                         return Nullable.LiftedNull.CreateFromExpression (ec, b);
 255                                 }
 256
 257                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 258                                         return null;
 259
 260                                 ///
 261                                 /// int operator &(int x, int y);
 262                                 /// uint operator &(uint x, uint y);
 263                                 /// long operator &(long x, long y);
 264                                 /// ulong operator &(ulong x, ulong y);
 265                                 ///
 266                                 if (left is IntConstant){
 267                                         int res = ((IntConstant) left).Value & ((IntConstant) right).Value;
 268                                         return new IntConstant (res, left.Location);
 269                                 }
 270                                 if (left is UIntConstant){
 271                                         uint res = ((UIntConstant)left).Value & ((UIntConstant)right).Value;
 272                                         return new UIntConstant (res, left.Location);
 273                                 }
 274                                 if (left is LongConstant){
 275                                         long res = ((LongConstant)left).Value & ((LongConstant)right).Value;
 276                                         return new LongConstant (res, left.Location);
 277                                 }
 278                                 if (left is ULongConstant){
 279                                         ulong res = ((ULongConstant)left).Value &
 280                                                 ((ULongConstant)right).Value;
 281
 282                                         return new ULongConstant (res, left.Location);
 283                                 }
 284                                 break;
 285
 286                         case Binary.Operator.ExclusiveOr:
 287                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 288                                         return null;
 289
 290                                 if (left is IntConstant){
 291                                         int res = ((IntConstant) left).Value ^ ((IntConstant) right).Value;
 292                                         return new IntConstant (res, left.Location);
 293                                 }
 294                                 if (left is UIntConstant){
 295                                         uint res = ((UIntConstant)left).Value ^ ((UIntConstant)right).Value;
 296
 297                                         return  new UIntConstant (res, left.Location);
 298                                 }
 299                                 if (left is LongConstant){
 300                                         long res = ((LongConstant)left).Value ^ ((LongConstant)right).Value;
 301
 302                                         return new LongConstant (res, left.Location);
 303                                 }
 304                                 if (left is ULongConstant){
 305                                         ulong res = ((ULongConstant)left).Value ^
 306                                                 ((ULongConstant)right).Value;
 307
 308                                         return new ULongConstant (res, left.Location);
 309                                 }
 310                                 break;
 311
 312                         case Binary.Operator.Addition:
 313                                 if (lt == InternalType.Null)
 314                                         return right;
 315
 316                                 if (rt == InternalType.Null)
 317                                         return left;
 318
 319                                 //
 320                                 // If both sides are strings, then concatenate, if
 321                                 // one is a string, and the other is not, then defer
 322                                 // to runtime concatenation
 323                                 //
 324                                 if (lt == TypeManager.string_type || rt == TypeManager.string_type){
 325                                         if (lt == rt)
 326                                                 return new StringConstant ((string)left.GetValue () + (string)right.GetValue (),
 327                                                         left.Location);
 328
 329                                         return null;
 330                                 }
 331
 332                                 //
 333                                 // handle "E operator + (E x, U y)"
 334                                 // handle "E operator + (Y y, E x)"
 335                                 //
 336                                 EnumConstant lc = left as EnumConstant;
 337                                 EnumConstant rc = right as EnumConstant;
 338                                 if (lc != null || rc != null){
 339                                         if (lc == null) {
 340                                                 lc = rc;
 341                                                 lt = lc.Type;
 342                                                 right = left;
 343                                         }
 344
 345                                         // U has to be implicitly convetible to E.base
 346                                         right = right.ConvertImplicitly (ec, lc.Child.Type);
 347                                         if (right == null)
 348                                                 return null;
 349
 350                                         result = BinaryFold (ec, oper, lc.Child, right, loc);
 351                                         if (result == null)
 352                                                 return null;
 353
 354                                         result = result.Resolve (ec).TryReduce (ec, lt, loc);
 355                                         if (result == null)
 356                                                 return null;
 357
 358                                         return new EnumConstant (result, lt);
 359                                 }
 360
 361                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 362                                         return null;
 363
 364                                 try {
 365                                         if (left is DoubleConstant){
 366                                                 double res;
 367
 368                                                 if (ec.ConstantCheckState)
 369                                                         res = checked (((DoubleConstant) left).Value +
 370                                                                        ((DoubleConstant) right).Value);
 371                                                 else
 372                                                         res = unchecked (((DoubleConstant) left).Value +
 373                                                                          ((DoubleConstant) right).Value);
 374
 375                                                 return new DoubleConstant (res, left.Location);
 376                                         }
 377                                         if (left is FloatConstant){
 378                                                 float res;
 379
 380                                                 if (ec.ConstantCheckState)
 381                                                         res = checked (((FloatConstant) left).Value +
 382                                                                        ((FloatConstant) right).Value);
 383                                                 else
 384                                                         res = unchecked (((FloatConstant) left).Value +
 385                                                                          ((FloatConstant) right).Value);
 386
 387                                                 result = new FloatConstant (res, left.Location);
 388                                         } else if (left is ULongConstant){
 389                                                 ulong res;
 390
 391                                                 if (ec.ConstantCheckState)
 392                                                         res = checked (((ULongConstant) left).Value +
 393                                                                        ((ULongConstant) right).Value);
 394                                                 else
 395                                                         res = unchecked (((ULongConstant) left).Value +
 396                                                                          ((ULongConstant) right).Value);
 397
 398                                                 result = new ULongConstant (res, left.Location);
 399                                         } else if (left is LongConstant){
 400                                                 long res;
 401
 402                                                 if (ec.ConstantCheckState)
 403                                                         res = checked (((LongConstant) left).Value +
 404                                                                        ((LongConstant) right).Value);
 405                                                 else
 406                                                         res = unchecked (((LongConstant) left).Value +
 407                                                                          ((LongConstant) right).Value);
 408
 409                                                 result = new LongConstant (res, left.Location);
 410                                         } else if (left is UIntConstant){
 411                                                 uint res;
 412
 413                                                 if (ec.ConstantCheckState)
 414                                                         res = checked (((UIntConstant) left).Value +
 415                                                                        ((UIntConstant) right).Value);
 416                                                 else
 417                                                         res = unchecked (((UIntConstant) left).Value +
 418                                                                          ((UIntConstant) right).Value);
 419
 420                                                 result = new UIntConstant (res, left.Location);
 421                                         } else if (left is IntConstant){
 422                                                 int res;
 423
 424                                                 if (ec.ConstantCheckState)
 425                                                         res = checked (((IntConstant) left).Value +
 426                                                                        ((IntConstant) right).Value);
 427                                                 else
 428                                                         res = unchecked (((IntConstant) left).Value +
 429                                                                          ((IntConstant) right).Value);
 430
 431                                                 result = new IntConstant (res, left.Location);
 432                                         } else if (left is DecimalConstant) {
 433                                                 decimal res;
 434
 435                                                 if (ec.ConstantCheckState)
 436                                                         res = checked (((DecimalConstant) left).Value +
 437                                                                 ((DecimalConstant) right).Value);
 438                                                 else
 439                                                         res = unchecked (((DecimalConstant) left).Value +
 440                                                                 ((DecimalConstant) right).Value);
 441
 442                                                 result = new DecimalConstant (res, left.Location);
 443                                         }
 444                                 } catch (OverflowException){
 445                                         Error_CompileTimeOverflow (ec, loc);
 446                                 }
 447
 448                                 return result;
 449
 450                         case Binary.Operator.Subtraction:
 451                                 //
 452                                 // handle "E operator - (E x, U y)"
 453                                 // handle "E operator - (Y y, E x)"
 454                                 //
 455                                 lc = left as EnumConstant;
 456                                 rc = right as EnumConstant;
 457                                 if (lc != null || rc != null){
 458                                         if (lc == null) {
 459                                                 lc = rc;
 460                                                 lt = lc.Type;
 461                                                 right = left;
 462                                         }
 463
 464                                         // U has to be implicitly convetible to E.base
 465                                         right = right.ConvertImplicitly (ec, lc.Child.Type);
 466                                         if (right == null)
 467                                                 return null;
 468
 469                                         result = BinaryFold (ec, oper, lc.Child, right, loc);
 470                                         if (result == null)
 471                                                 return null;
 472
 473                                         result = result.Resolve (ec).TryReduce (ec, lt, loc);
 474                                         if (result == null)
 475                                                 return null;
 476
 477                                         return new EnumConstant (result, lt);
 478                                 }
 479
 480                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 481                                         return null;
 482
 483                                 try {
 484                                         if (left is DoubleConstant){
 485                                                 double res;
 486
 487                                                 if (ec.ConstantCheckState)
 488                                                         res = checked (((DoubleConstant) left).Value -
 489                                                                        ((DoubleConstant) right).Value);
 490                                                 else
 491                                                         res = unchecked (((DoubleConstant) left).Value -
 492                                                                          ((DoubleConstant) right).Value);
 493
 494                                                 result = new DoubleConstant (res, left.Location);
 495                                         } else if (left is FloatConstant){
 496                                                 float res;
 497
 498                                                 if (ec.ConstantCheckState)
 499                                                         res = checked (((FloatConstant) left).Value -
 500                                                                        ((FloatConstant) right).Value);
 501                                                 else
 502                                                         res = unchecked (((FloatConstant) left).Value -
 503                                                                          ((FloatConstant) right).Value);
 504
 505                                                 result = new FloatConstant (res, left.Location);
 506                                         } else if (left is ULongConstant){
 507                                                 ulong res;
 508
 509                                                 if (ec.ConstantCheckState)
 510                                                         res = checked (((ULongConstant) left).Value -
 511                                                                        ((ULongConstant) right).Value);
 512                                                 else
 513                                                         res = unchecked (((ULongConstant) left).Value -
 514                                                                          ((ULongConstant) right).Value);
 515
 516                                                 result = new ULongConstant (res, left.Location);
 517                                         } else if (left is LongConstant){
 518                                                 long res;
 519
 520                                                 if (ec.ConstantCheckState)
 521                                                         res = checked (((LongConstant) left).Value -
 522                                                                        ((LongConstant) right).Value);
 523                                                 else
 524                                                         res = unchecked (((LongConstant) left).Value -
 525                                                                          ((LongConstant) right).Value);
 526
 527                                                 result = new LongConstant (res, left.Location);
 528                                         } else if (left is UIntConstant){
 529                                                 uint res;
 530
 531                                                 if (ec.ConstantCheckState)
 532                                                         res = checked (((UIntConstant) left).Value -
 533                                                                        ((UIntConstant) right).Value);
 534                                                 else
 535                                                         res = unchecked (((UIntConstant) left).Value -
 536                                                                          ((UIntConstant) right).Value);
 537
 538                                                 result = new UIntConstant (res, left.Location);
 539                                         } else if (left is IntConstant){
 540                                                 int res;
 541
 542                                                 if (ec.ConstantCheckState)
 543                                                         res = checked (((IntConstant) left).Value -
 544                                                                        ((IntConstant) right).Value);
 545                                                 else
 546                                                         res = unchecked (((IntConstant) left).Value -
 547                                                                          ((IntConstant) right).Value);
 548
 549                                                 result = new IntConstant (res, left.Location);
 550                                         } else if (left is DecimalConstant) {
 551                                                 decimal res;
 552
 553                                                 if (ec.ConstantCheckState)
 554                                                         res = checked (((DecimalConstant) left).Value -
 555                                                                 ((DecimalConstant) right).Value);
 556                                                 else
 557                                                         res = unchecked (((DecimalConstant) left).Value -
 558                                                                 ((DecimalConstant) right).Value);
 559
 560                                                 return new DecimalConstant (res, left.Location);
 561                                         } else {
 562                                                 throw new Exception ( "Unexepected subtraction input: " + left);
 563                                         }
 564                                 } catch (OverflowException){
 565                                         Error_CompileTimeOverflow (ec, loc);
 566                                 }
 567
 568                                 return result;
 569
 570                         case Binary.Operator.Multiply:
 571                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 572                                         return null;
 573
 574                                 try {
 575                                         if (left is DoubleConstant){
 576                                                 double res;
 577
 578                                                 if (ec.ConstantCheckState)
 579                                                         res = checked (((DoubleConstant) left).Value *
 580                                                                 ((DoubleConstant) right).Value);
 581                                                 else
 582                                                         res = unchecked (((DoubleConstant) left).Value *
 583                                                                 ((DoubleConstant) right).Value);
 584
 585                                                 return new DoubleConstant (res, left.Location);
 586                                         } else if (left is FloatConstant){
 587                                                 float res;
 588
 589                                                 if (ec.ConstantCheckState)
 590                                                         res = checked (((FloatConstant) left).Value *
 591                                                                 ((FloatConstant) right).Value);
 592                                                 else
 593                                                         res = unchecked (((FloatConstant) left).Value *
 594                                                                 ((FloatConstant) right).Value);
 595
 596                                                 return new FloatConstant (res, left.Location);
 597                                         } else if (left is ULongConstant){
 598                                                 ulong res;
 599
 600                                                 if (ec.ConstantCheckState)
 601                                                         res = checked (((ULongConstant) left).Value *
 602                                                                 ((ULongConstant) right).Value);
 603                                                 else
 604                                                         res = unchecked (((ULongConstant) left).Value *
 605                                                                 ((ULongConstant) right).Value);
 606
 607                                                 return new ULongConstant (res, left.Location);
 608                                         } else if (left is LongConstant){
 609                                                 long res;
 610
 611                                                 if (ec.ConstantCheckState)
 612                                                         res = checked (((LongConstant) left).Value *
 613                                                                 ((LongConstant) right).Value);
 614                                                 else
 615                                                         res = unchecked (((LongConstant) left).Value *
 616                                                                 ((LongConstant) right).Value);
 617
 618                                                 return new LongConstant (res, left.Location);
 619                                         } else if (left is UIntConstant){
 620                                                 uint res;
 621
 622                                                 if (ec.ConstantCheckState)
 623                                                         res = checked (((UIntConstant) left).Value *
 624                                                                 ((UIntConstant) right).Value);
 625                                                 else
 626                                                         res = unchecked (((UIntConstant) left).Value *
 627                                                                 ((UIntConstant) right).Value);
 628
 629                                                 return new UIntConstant (res, left.Location);
 630                                         } else if (left is IntConstant){
 631                                                 int res;
 632
 633                                                 if (ec.ConstantCheckState)
 634                                                         res = checked (((IntConstant) left).Value *
 635                                                                 ((IntConstant) right).Value);
 636                                                 else
 637                                                         res = unchecked (((IntConstant) left).Value *
 638                                                                 ((IntConstant) right).Value);
 639
 640                                                 return new IntConstant (res, left.Location);
 641                                         } else if (left is DecimalConstant) {
 642                                                 decimal res;
 643
 644                                                 if (ec.ConstantCheckState)
 645                                                         res = checked (((DecimalConstant) left).Value *
 646                                                                 ((DecimalConstant) right).Value);
 647                                                 else
 648                                                         res = unchecked (((DecimalConstant) left).Value *
 649                                                                 ((DecimalConstant) right).Value);
 650
 651                                                 return new DecimalConstant (res, left.Location);
 652                                         } else {
 653                                                 throw new Exception ( "Unexepected multiply input: " + left);
 654                                         }
 655                                 } catch (OverflowException){
 656                                         Error_CompileTimeOverflow (ec, loc);
 657                                 }
 658                                 break;
 659
 660                         case Binary.Operator.Division:
 661                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 662                                         return null;
 663
 664                                 try {
 665                                         if (left is DoubleConstant){
 666                                                 double res;
 667
 668                                                 if (ec.ConstantCheckState)
 669                                                         res = checked (((DoubleConstant) left).Value /
 670                                                                 ((DoubleConstant) right).Value);
 671                                                 else
 672                                                         res = unchecked (((DoubleConstant) left).Value /
 673                                                                 ((DoubleConstant) right).Value);
 674
 675                                                 return new DoubleConstant (res, left.Location);
 676                                         } else if (left is FloatConstant){
 677                                                 float res;
 678
 679                                                 if (ec.ConstantCheckState)
 680                                                         res = checked (((FloatConstant) left).Value /
 681                                                                 ((FloatConstant) right).Value);
 682                                                 else
 683                                                         res = unchecked (((FloatConstant) left).Value /
 684                                                                 ((FloatConstant) right).Value);
 685
 686                                                 return new FloatConstant (res, left.Location);
 687                                         } else if (left is ULongConstant){
 688                                                 ulong res;
 689
 690                                                 if (ec.ConstantCheckState)
 691                                                         res = checked (((ULongConstant) left).Value /
 692                                                                 ((ULongConstant) right).Value);
 693                                                 else
 694                                                         res = unchecked (((ULongConstant) left).Value /
 695                                                                 ((ULongConstant) right).Value);
 696
 697                                                 return new ULongConstant (res, left.Location);
 698                                         } else if (left is LongConstant){
 699                                                 long res;
 700
 701                                                 if (ec.ConstantCheckState)
 702                                                         res = checked (((LongConstant) left).Value /
 703                                                                 ((LongConstant) right).Value);
 704                                                 else
 705                                                         res = unchecked (((LongConstant) left).Value /
 706                                                                 ((LongConstant) right).Value);
 707
 708                                                 return new LongConstant (res, left.Location);
 709                                         } else if (left is UIntConstant){
 710                                                 uint res;
 711
 712                                                 if (ec.ConstantCheckState)
 713                                                         res = checked (((UIntConstant) left).Value /
 714                                                                 ((UIntConstant) right).Value);
 715                                                 else
 716                                                         res = unchecked (((UIntConstant) left).Value /
 717                                                                 ((UIntConstant) right).Value);
 718
 719                                                 return new UIntConstant (res, left.Location);
 720                                         } else if (left is IntConstant){
 721                                                 int res;
 722
 723                                                 if (ec.ConstantCheckState)
 724                                                         res = checked (((IntConstant) left).Value /
 725                                                                 ((IntConstant) right).Value);
 726                                                 else
 727                                                         res = unchecked (((IntConstant) left).Value /
 728                                                                 ((IntConstant) right).Value);
 729
 730                                                 return new IntConstant (res, left.Location);
 731                                         } else if (left is DecimalConstant) {
 732                                                 decimal res;
 733
 734                                                 if (ec.ConstantCheckState)
 735                                                         res = checked (((DecimalConstant) left).Value /
 736                                                                 ((DecimalConstant) right).Value);
 737                                                 else
 738                                                         res = unchecked (((DecimalConstant) left).Value /
 739                                                                 ((DecimalConstant) right).Value);
 740
 741                                                 return new DecimalConstant (res, left.Location);
 742                                         } else {
 743                                                 throw new Exception ( "Unexepected division input: " + left);
 744                                         }
 745                                 } catch (OverflowException){
 746                                         Error_CompileTimeOverflow (ec, loc);
 747
 748                                 } catch (DivideByZeroException) {
 749                                         ec.Report.Error (20, loc, "Division by constant zero");
 750                                 }
 751
 752                                 break;
 753
 754                         case Binary.Operator.Modulus:
 755                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 756                                         return null;
 757
 758                                 try {
 759                                         if (left is DoubleConstant){
 760                                                 double res;
 761
 762                                                 if (ec.ConstantCheckState)
 763                                                         res = checked (((DoubleConstant) left).Value %
 764                                                                        ((DoubleConstant) right).Value);
 765                                                 else
 766                                                         res = unchecked (((DoubleConstant) left).Value %
 767                                                                          ((DoubleConstant) right).Value);
 768
 769                                                 return new DoubleConstant (res, left.Location);
 770                                         } else if (left is FloatConstant){
 771                                                 float res;
 772
 773                                                 if (ec.ConstantCheckState)
 774                                                         res = checked (((FloatConstant) left).Value %
 775                                                                        ((FloatConstant) right).Value);
 776                                                 else
 777                                                         res = unchecked (((FloatConstant) left).Value %
 778                                                                          ((FloatConstant) right).Value);
 779
 780                                                 return new FloatConstant (res, left.Location);
 781                                         } else if (left is ULongConstant){
 782                                                 ulong res;
 783
 784                                                 if (ec.ConstantCheckState)
 785                                                         res = checked (((ULongConstant) left).Value %
 786                                                                        ((ULongConstant) right).Value);
 787                                                 else
 788                                                         res = unchecked (((ULongConstant) left).Value %
 789                                                                          ((ULongConstant) right).Value);
 790
 791                                                 return new ULongConstant (res, left.Location);
 792                                         } else if (left is LongConstant){
 793                                                 long res;
 794
 795                                                 if (ec.ConstantCheckState)
 796                                                         res = checked (((LongConstant) left).Value %
 797                                                                        ((LongConstant) right).Value);
 798                                                 else
 799                                                         res = unchecked (((LongConstant) left).Value %
 800                                                                          ((LongConstant) right).Value);
 801
 802                                                 return new LongConstant (res, left.Location);
 803                                         } else if (left is UIntConstant){
 804                                                 uint res;
 805
 806                                                 if (ec.ConstantCheckState)
 807                                                         res = checked (((UIntConstant) left).Value %
 808                                                                        ((UIntConstant) right).Value);
 809                                                 else
 810                                                         res = unchecked (((UIntConstant) left).Value %
 811                                                                          ((UIntConstant) right).Value);
 812
 813                                                 return new UIntConstant (res, left.Location);
 814                                         } else if (left is IntConstant){
 815                                                 int res;
 816
 817                                                 if (ec.ConstantCheckState)
 818                                                         res = checked (((IntConstant) left).Value %
 819                                                                        ((IntConstant) right).Value);
 820                                                 else
 821                                                         res = unchecked (((IntConstant) left).Value %
 822                                                                          ((IntConstant) right).Value);
 823
 824                                                 return new IntConstant (res, left.Location);
 825                                         } else {
 826                                                 throw new Exception ( "Unexepected modulus input: " + left);
 827                                         }
 828                                 } catch (DivideByZeroException){
 829                                         ec.Report.Error (20, loc, "Division by constant zero");
 830                                 } catch (OverflowException){
 831                                         Error_CompileTimeOverflow (ec, loc);
 832                                 }
 833                                 break;
 834
 835                                 //
 836                                 // There is no overflow checking on left shift
 837                                 //
 838                         case Binary.Operator.LeftShift:
 839                                 IntConstant ic = right.ConvertImplicitly (ec, TypeManager.int32_type) as IntConstant;
 840                                 if (ic == null){
 841                                         Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc);
 842                                         return null;
 843                                 }
 844
 845                                 int lshift_val = ic.Value;
 846                                 if (left.Type == TypeManager.uint64_type)
 847                                         return new ULongConstant (((ULongConstant)left).Value << lshift_val, left.Location);
 848                                 if (left.Type == TypeManager.int64_type)
 849                                         return new LongConstant (((LongConstant)left).Value << lshift_val, left.Location);
 850                                 if (left.Type == TypeManager.uint32_type)
 851                                         return new UIntConstant (((UIntConstant)left).Value << lshift_val, left.Location);
 852
 853                                 // null << value => null
 854                                 if (left is NullLiteral)
 855                                         return (Constant) new Nullable.LiftedBinaryOperator (oper, left, right, loc).Resolve (ec);
 856
 857                                 left = left.ConvertImplicitly (ec, TypeManager.int32_type);
 858                                 if (left.Type == TypeManager.int32_type)
 859                                         return new IntConstant (((IntConstant)left).Value << lshift_val, left.Location);
 860
 861                                 Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc);
 862                                 break;
 863
 864                                 //
 865                                 // There is no overflow checking on right shift
 866                                 //
 867                         case Binary.Operator.RightShift:
 868                                 IntConstant sic = right.ConvertImplicitly (ec, TypeManager.int32_type) as IntConstant;
 869                                 if (sic == null){
 870                                         Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc); ;
 871                                         return null;
 872                                 }
 873                                 int rshift_val = sic.Value;
 874                                 if (left.Type == TypeManager.uint64_type)
 875                                         return new ULongConstant (((ULongConstant)left).Value >> rshift_val, left.Location);
 876                                 if (left.Type == TypeManager.int64_type)
 877                                         return new LongConstant (((LongConstant)left).Value >> rshift_val, left.Location);
 878                                 if (left.Type == TypeManager.uint32_type)
 879                                         return new UIntConstant (((UIntConstant)left).Value >> rshift_val, left.Location);
 880
 881                                 // null >> value => null
 882                                 if (left is NullLiteral)
 883                                         return (Constant) new Nullable.LiftedBinaryOperator (oper, left, right, loc).Resolve (ec);
 884
 885                                 left = left.ConvertImplicitly (ec, TypeManager.int32_type);
 886                                 if (left.Type == TypeManager.int32_type)
 887                                         return new IntConstant (((IntConstant)left).Value >> rshift_val, left.Location);
 888
 889                                 Binary.Error_OperatorCannotBeApplied (ec, left, right, oper, loc);
 890                                 break;
 891
 892                         case Binary.Operator.Equality:
 893                                 if (TypeManager.IsReferenceType (lt) && TypeManager.IsReferenceType (rt) ||
 894                                         (left is Nullable.LiftedNull && right.IsNull) ||
 895                                         (right is Nullable.LiftedNull && left.IsNull)) {
 896                                         if (left.IsNull || right.IsNull) {
 897                                                 return ReducedExpression.Create (
 898                                                         new BoolConstant (left.IsNull == right.IsNull, left.Location).Resolve (ec),
 899                                                         new Binary (oper, left, right, loc));
 900                                         }
 901
 902                                         if (left is StringConstant && right is StringConstant)
 903                                                 return new BoolConstant (
 904                                                         ((StringConstant) left).Value == ((StringConstant) right).Value, left.Location);
 905
 906                                         return null;
 907                                 }
 908
 909                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 910                                         return null;
 911
 912                                 bool_res = false;
 913                                 if (left is DoubleConstant)
 914                                         bool_res = ((DoubleConstant) left).Value ==
 915                                                 ((DoubleConstant) right).Value;
 916                                 else if (left is FloatConstant)
 917                                         bool_res = ((FloatConstant) left).Value ==
 918                                                 ((FloatConstant) right).Value;
 919                                 else if (left is ULongConstant)
 920                                         bool_res = ((ULongConstant) left).Value ==
 921                                                 ((ULongConstant) right).Value;
 922                                 else if (left is LongConstant)
 923                                         bool_res = ((LongConstant) left).Value ==
 924                                                 ((LongConstant) right).Value;
 925                                 else if (left is UIntConstant)
 926                                         bool_res = ((UIntConstant) left).Value ==
 927                                                 ((UIntConstant) right).Value;
 928                                 else if (left is IntConstant)
 929                                         bool_res = ((IntConstant) left).Value ==
 930                                                 ((IntConstant) right).Value;
 931                                 else
 932                                         return null;
 933
 934                                 return new BoolConstant (bool_res, left.Location);
 935
 936                         case Binary.Operator.Inequality:
 937                                 if (TypeManager.IsReferenceType (lt) && TypeManager.IsReferenceType (rt) ||
 938                                         (left is Nullable.LiftedNull && right.IsNull) ||
 939                                         (right is Nullable.LiftedNull && left.IsNull)) {
 940                                         if (left.IsNull || right.IsNull) {
 941                                                 return ReducedExpression.Create (
 942                                                         new BoolConstant (left.IsNull != right.IsNull, left.Location).Resolve (ec),
 943                                                         new Binary (oper, left, right, loc));
 944                                         }
 945
 946                                         if (left is StringConstant && right is StringConstant)
 947                                                 return new BoolConstant (
 948                                                         ((StringConstant) left).Value != ((StringConstant) right).Value, left.Location);
 949
 950                                         return null;
 951                                 }
 952
 953                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 954                                         return null;
 955
 956                                 bool_res = false;
 957                                 if (left is DoubleConstant)
 958                                         bool_res = ((DoubleConstant) left).Value !=
 959                                                 ((DoubleConstant) right).Value;
 960                                 else if (left is FloatConstant)
 961                                         bool_res = ((FloatConstant) left).Value !=
 962                                                 ((FloatConstant) right).Value;
 963                                 else if (left is ULongConstant)
 964                                         bool_res = ((ULongConstant) left).Value !=
 965                                                 ((ULongConstant) right).Value;
 966                                 else if (left is LongConstant)
 967                                         bool_res = ((LongConstant) left).Value !=
 968                                                 ((LongConstant) right).Value;
 969                                 else if (left is UIntConstant)
 970                                         bool_res = ((UIntConstant) left).Value !=
 971                                                 ((UIntConstant) right).Value;
 972                                 else if (left is IntConstant)
 973                                         bool_res = ((IntConstant) left).Value !=
 974                                                 ((IntConstant) right).Value;
 975                                 else
 976                                         return null;
 977
 978                                 return new BoolConstant (bool_res, left.Location);
 979
 980                         case Binary.Operator.LessThan:
 981                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
 982                                         return null;
 983
 984                                 bool_res = false;
 985                                 if (left is DoubleConstant)
 986                                         bool_res = ((DoubleConstant) left).Value <
 987                                                 ((DoubleConstant) right).Value;
 988                                 else if (left is FloatConstant)
 989                                         bool_res = ((FloatConstant) left).Value <
 990                                                 ((FloatConstant) right).Value;
 991                                 else if (left is ULongConstant)
 992                                         bool_res = ((ULongConstant) left).Value <
 993                                                 ((ULongConstant) right).Value;
 994                                 else if (left is LongConstant)
 995                                         bool_res = ((LongConstant) left).Value <
 996                                                 ((LongConstant) right).Value;
 997                                 else if (left is UIntConstant)
 998                                         bool_res = ((UIntConstant) left).Value <
 999                                                 ((UIntConstant) right).Value;
1000                                 else if (left is IntConstant)
1001                                         bool_res = ((IntConstant) left).Value <
1002                                                 ((IntConstant) right).Value;
1003                                 else
1004                                         return null;
1005
1006                                 return new BoolConstant (bool_res, left.Location);
1007
1008                         case Binary.Operator.GreaterThan:
1009                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
1010                                         return null;
1011
1012                                 bool_res = false;
1013                                 if (left is DoubleConstant)
1014                                         bool_res = ((DoubleConstant) left).Value >
1015                                                 ((DoubleConstant) right).Value;
1016                                 else if (left is FloatConstant)
1017                                         bool_res = ((FloatConstant) left).Value >
1018                                                 ((FloatConstant) right).Value;
1019                                 else if (left is ULongConstant)
1020                                         bool_res = ((ULongConstant) left).Value >
1021                                                 ((ULongConstant) right).Value;
1022                                 else if (left is LongConstant)
1023                                         bool_res = ((LongConstant) left).Value >
1024                                                 ((LongConstant) right).Value;
1025                                 else if (left is UIntConstant)
1026                                         bool_res = ((UIntConstant) left).Value >
1027                                                 ((UIntConstant) right).Value;
1028                                 else if (left is IntConstant)
1029                                         bool_res = ((IntConstant) left).Value >
1030                                                 ((IntConstant) right).Value;
1031                                 else
1032                                         return null;
1033
1034                                 return new BoolConstant (bool_res, left.Location);
1035
1036                         case Binary.Operator.GreaterThanOrEqual:
1037                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
1038                                         return null;
1039
1040                                 bool_res = false;
1041                                 if (left is DoubleConstant)
1042                                         bool_res = ((DoubleConstant) left).Value >=
1043                                                 ((DoubleConstant) right).Value;
1044                                 else if (left is FloatConstant)
1045                                         bool_res = ((FloatConstant) left).Value >=
1046                                                 ((FloatConstant) right).Value;
1047                                 else if (left is ULongConstant)
1048                                         bool_res = ((ULongConstant) left).Value >=
1049                                                 ((ULongConstant) right).Value;
1050                                 else if (left is LongConstant)
1051                                         bool_res = ((LongConstant) left).Value >=
1052                                                 ((LongConstant) right).Value;
1053                                 else if (left is UIntConstant)
1054                                         bool_res = ((UIntConstant) left).Value >=
1055                                                 ((UIntConstant) right).Value;
1056                                 else if (left is IntConstant)
1057                                         bool_res = ((IntConstant) left).Value >=
1058                                                 ((IntConstant) right).Value;
1059                                 else
1060                                         return null;
1061
1062                                 return new BoolConstant (bool_res, left.Location);
1063
1064                         case Binary.Operator.LessThanOrEqual:
1065                                 if (!DoBinaryNumericPromotions (ec, ref left, ref right))
1066                                         return null;
1067
1068                                 bool_res = false;
1069                                 if (left is DoubleConstant)
1070                                         bool_res = ((DoubleConstant) left).Value <=
1071                                                 ((DoubleConstant) right).Value;
1072                                 else if (left is FloatConstant)
1073                                         bool_res = ((FloatConstant) left).Value <=
1074                                                 ((FloatConstant) right).Value;
1075                                 else if (left is ULongConstant)
1076                                         bool_res = ((ULongConstant) left).Value <=
1077                                                 ((ULongConstant) right).Value;
1078                                 else if (left is LongConstant)
1079                                         bool_res = ((LongConstant) left).Value <=
1080                                                 ((LongConstant) right).Value;
1081                                 else if (left is UIntConstant)
1082                                         bool_res = ((UIntConstant) left).Value <=
1083                                                 ((UIntConstant) right).Value;
1084                                 else if (left is IntConstant)
1085                                         bool_res = ((IntConstant) left).Value <=
1086                                                 ((IntConstant) right).Value;
1087                                 else
1088                                         return null;
1089
1090                                 return new BoolConstant (bool_res, left.Location);
1091                         }
1092
1093                         return null;
1094                 }
1095         }
1096 }