mcs/class/System.Core/System.Linq.Expressions/BinaryExpression.cs

   1 //
   2 // BinaryExpression.cs
   3 //
   4 // Author:
   5 //   Jb Evain (jbevain@novell.com)
   6 //   Miguel de Icaza (miguel@novell.com)
   7 //
   8 // Contains code from the Mono C# compiler:
   9 //   Marek Safar (marek.safar@seznam.cz)
  10 //   Martin Baulig (martin@ximian.com)
  11 //   Raja Harinath (harinath@gmail.com)
  12 //
  13 // (C) 2001-2003 Ximian, Inc.
  14 // (C) 2004-2008 Novell, Inc. (http://www.novell.com)
  15 //
  16 // Permission is hereby granted, free of charge, to any person obtaining
  17 // a copy of this software and associated documentation files (the
  18 // "Software"), to deal in the Software without restriction, including
  19 // without limitation the rights to use, copy, modify, merge, publish,
  20 // distribute, sublicense, and/or sell copies of the Software, and to
  21 // permit persons to whom the Software is furnished to do so, subject to
  22 // the following conditions:
  23 //
  24 // The above copyright notice and this permission notice shall be
  25 // included in all copies or substantial portions of the Software.
  26 //
  27 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  28 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  29 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  30 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  31 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  32 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  33 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  34 //
  35
  36 using System;
  37 using System.Reflection;
  38 using System.Reflection.Emit;
  39
  40 namespace System.Linq.Expressions {
  41
  42         public sealed class BinaryExpression : Expression {
  43
  44                 Expression left;
  45                 Expression right;
  46                 LambdaExpression conversion;
  47                 MethodInfo method;
  48                 bool lift_to_null, is_lifted;
  49
  50                 public Expression Left {
  51                         get { return left; }
  52                 }
  53
  54                 public Expression Right {
  55                         get { return right; }
  56                 }
  57
  58                 public MethodInfo Method {
  59                         get { return method; }
  60                 }
  61
  62                 public bool IsLifted {
  63                         get { return is_lifted;  }
  64                 }
  65
  66                 public bool IsLiftedToNull {
  67                         get { return lift_to_null; }
  68                 }
  69
  70                 public LambdaExpression Conversion {
  71                         get { return conversion; }
  72                 }
  73
  74                 internal BinaryExpression (ExpressionType node_type, Type type, Expression left, Expression right)
  75                         : base (node_type, type)
  76                 {
  77                         this.left = left;
  78                         this.right = right;
  79                 }
  80
  81                 internal BinaryExpression (ExpressionType node_type, Type type, Expression left, Expression right, MethodInfo method)
  82                         : base (node_type, type)
  83                 {
  84                         this.left = left;
  85                         this.right = right;
  86                         this.method = method;
  87                 }
  88
  89                 internal BinaryExpression (ExpressionType node_type, Type type, Expression left, Expression right, bool lift_to_null,
  90                         bool is_lifted, MethodInfo method, LambdaExpression conversion) : base (node_type, type)
  91                 {
  92                         this.left = left;
  93                         this.right = right;
  94                         this.method = method;
  95                         this.conversion = conversion;
  96                         this.lift_to_null = lift_to_null;
  97                         this.is_lifted = is_lifted;
  98                 }
  99
 100                 void EmitArrayAccess (EmitContext ec)
 101                 {
 102                         left.Emit (ec);
 103                         right.Emit (ec);
 104                         ec.ig.Emit (OpCodes.Ldelem, this.Type);
 105                 }
 106
 107                 void EmitLogicalBinary (EmitContext ec)
 108                 {
 109                         switch (NodeType) {
 110                         case ExpressionType.And:
 111                         case ExpressionType.Or:
 112                                 if (!IsLifted)
 113                                         EmitLogical (ec);
 114                                 else if (Type == typeof (bool?))
 115                                         EmitLiftedLogical (ec);
 116                                 else
 117                                         EmitLiftedArithmeticBinary (ec);
 118                                 break;
 119                         case ExpressionType.AndAlso:
 120                         case ExpressionType.OrElse:
 121                                 if (!IsLifted)
 122                                         EmitLogicalShortCircuit (ec);
 123                                 else
 124                                         EmitLiftedLogicalShortCircuit (ec);
 125                                 break;
 126                         }
 127                 }
 128
 129                 void EmitLogical (EmitContext ec)
 130                 {
 131                         EmitNonLiftedBinary (ec);
 132                 }
 133
 134                 void EmitLiftedLogical (EmitContext ec)
 135                 {
 136                         var ig = ec.ig;
 137                         var and = NodeType == ExpressionType.And;
 138                         var left = ec.EmitStored (this.left);
 139                         var right = ec.EmitStored (this.right);
 140
 141                         var ret_from_left = ig.DefineLabel ();
 142                         var ret_from_right = ig.DefineLabel ();
 143                         var done = ig.DefineLabel ();
 144
 145                         ec.EmitNullableGetValueOrDefault (left);
 146                         ig.Emit (OpCodes.Brtrue, ret_from_left);
 147                         ec.EmitNullableGetValueOrDefault (right);
 148                         ig.Emit (OpCodes.Brtrue, ret_from_right);
 149
 150                         ec.EmitNullableHasValue (left);
 151                         ig.Emit (OpCodes.Brfalse, ret_from_left);
 152
 153                         ig.MarkLabel (ret_from_right);
 154                         ec.EmitLoad (and ? left : right);
 155                         ig.Emit (OpCodes.Br, done);
 156
 157                         ig.MarkLabel (ret_from_left);
 158                         ec.EmitLoad (and ? right : left);
 159
 160                         ig.MarkLabel (done);
 161                 }
 162
 163                 void EmitLogicalShortCircuit (EmitContext ec)
 164                 {
 165                         var ig = ec.ig;
 166                         var and = NodeType == ExpressionType.AndAlso;
 167                         var ret = ig.DefineLabel ();
 168                         var done = ig.DefineLabel ();
 169
 170                         ec.Emit (left);
 171                         ig.Emit (and ? OpCodes.Brfalse : OpCodes.Brtrue, ret);
 172
 173                         ec.Emit (right);
 174
 175                         ig.Emit (OpCodes.Br, done);
 176
 177                         ig.MarkLabel (ret);
 178                         ig.Emit (and ? OpCodes.Ldc_I4_0 : OpCodes.Ldc_I4_1);
 179
 180                         ig.MarkLabel (done);
 181                 }
 182
 183                 MethodInfo GetFalseOperator ()
 184                 {
 185                         return left.Type.GetMethod ("op_False", AllStatic);
 186                 }
 187
 188                 MethodInfo GetTrueOperator ()
 189                 {
 190                         return left.Type.GetMethod ("op_True", AllStatic);
 191                 }
 192
 193                 void EmitUserDefinedLogicalShortCircuit (EmitContext ec)
 194                 {
 195                         var ig = ec.ig;
 196                         var and = NodeType == ExpressionType.AndAlso;
 197
 198                         var done = ig.DefineLabel ();
 199
 200                         var left = ec.EmitStored (this.left);
 201
 202                         ec.EmitLoad (left);
 203                         ig.Emit (OpCodes.Dup);
 204                         ec.EmitCall (and ? GetFalseOperator () : GetTrueOperator ());
 205                         ig.Emit (OpCodes.Brtrue, done);
 206
 207                         ec.Emit (this.right);
 208                         ec.EmitCall (method);
 209
 210                         ig.MarkLabel (done);
 211                 }
 212
 213                 void EmitLiftedLogicalShortCircuit (EmitContext ec)
 214                 {
 215                         var ig = ec.ig;
 216                         var and = NodeType == ExpressionType.AndAlso;
 217                         var left_is_null = ig.DefineLabel ();
 218                         var ret_from_left = ig.DefineLabel ();
 219                         var ret_null = ig.DefineLabel ();
 220                         var ret_new = ig.DefineLabel();
 221                         var done = ig.DefineLabel();
 222
 223                         var left = ec.EmitStored (this.left);
 224
 225                         ec.EmitNullableHasValue (left);
 226                         ig.Emit (OpCodes.Brfalse, left_is_null);
 227
 228                         ec.EmitNullableGetValueOrDefault (left);
 229
 230                         ig.Emit (OpCodes.Ldc_I4_0);
 231                         ig.Emit (OpCodes.Ceq);
 232                         ig.Emit (and ? OpCodes.Brtrue : OpCodes.Brfalse, ret_from_left);
 233
 234                         ig.MarkLabel (left_is_null);
 235                         var right = ec.EmitStored (this.right);
 236
 237                         ec.EmitNullableHasValue (right);
 238                         ig.Emit (OpCodes.Brfalse_S, ret_null);
 239
 240                         ec.EmitNullableGetValueOrDefault (right);
 241
 242                         ig.Emit (OpCodes.Ldc_I4_0);
 243                         ig.Emit (OpCodes.Ceq);
 244
 245                         ig.Emit (and ? OpCodes.Brtrue : OpCodes.Brfalse, ret_from_left);
 246
 247                         ec.EmitNullableHasValue (left);
 248                         ig.Emit (OpCodes.Brfalse, ret_null);
 249
 250                         ig.Emit (and ? OpCodes.Ldc_I4_1 : OpCodes.Ldc_I4_0);
 251                         ig.Emit (OpCodes.Br_S, ret_new);
 252
 253                         ig.MarkLabel (ret_from_left);
 254                         ig.Emit (and ? OpCodes.Ldc_I4_0 : OpCodes.Ldc_I4_1);
 255
 256                         ig.MarkLabel (ret_new);
 257                         ec.EmitNullableNew (typeof (bool?));
 258                         ig.Emit (OpCodes.Br, done);
 259
 260                         ig.MarkLabel (ret_null);
 261                         var ret = ig.DeclareLocal (typeof (bool?));
 262                         ec.EmitNullableInitialize (ret);
 263
 264                         ig.MarkLabel (done);
 265                 }
 266
 267                 void EmitCoalesce (EmitContext ec)
 268                 {
 269                         var ig = ec.ig;
 270                         var done = ig.DefineLabel ();
 271                         var load_right = ig.DefineLabel ();
 272
 273                         var left = ec.EmitStored (this.left);
 274                         var left_is_nullable = left.LocalType.IsNullable ();
 275
 276                         if (left_is_nullable)
 277                                 ec.EmitNullableHasValue (left);
 278                         else
 279                                 ec.EmitLoad (left);
 280
 281                         ig.Emit (OpCodes.Brfalse, load_right);
 282
 283                         if (left_is_nullable && !Type.IsNullable ())
 284                                 ec.EmitNullableGetValue (left);
 285                         else
 286                                 ec.EmitLoad (left);
 287
 288                         ig.Emit (OpCodes.Br, done);
 289
 290                         ig.MarkLabel (load_right);
 291                         ec.Emit (this.right);
 292
 293                         ig.MarkLabel (done);
 294                 }
 295
 296                 void EmitConvertedCoalesce (EmitContext ec)
 297                 {
 298                         throw new NotImplementedException ();
 299                 }
 300
 301                 static bool IsInt32OrInt64 (Type type)
 302                 {
 303                         return type == typeof (int) || type == typeof (long);
 304                 }
 305
 306                 static bool IsSingleOrDouble (Type type)
 307                 {
 308                         return type == typeof (float) || type == typeof (double);
 309                 }
 310
 311                 void EmitBinaryOperator (EmitContext ec)
 312                 {
 313                         var ig = ec.ig;
 314                         bool is_unsigned = IsUnsigned (left.Type);
 315
 316                         switch (NodeType) {
 317                         case ExpressionType.Add:
 318                                 ig.Emit (OpCodes.Add);
 319                                 break;
 320                         case ExpressionType.AddChecked:
 321                                 if (IsInt32OrInt64 (left.Type))
 322                                         ig.Emit (OpCodes.Add_Ovf);
 323                                 else
 324                                         ig.Emit (is_unsigned ? OpCodes.Add_Ovf_Un : OpCodes.Add);
 325                                 break;
 326                         case ExpressionType.Subtract:
 327                                 ig.Emit (OpCodes.Sub);
 328                                 break;
 329                         case ExpressionType.SubtractChecked:
 330                                 if (IsInt32OrInt64 (left.Type))
 331                                         ig.Emit (OpCodes.Sub_Ovf);
 332                                 else
 333                                         ig.Emit (is_unsigned ? OpCodes.Sub_Ovf_Un : OpCodes.Sub);
 334                                 break;
 335                         case ExpressionType.Multiply:
 336                                 ig.Emit (OpCodes.Mul);
 337                                 break;
 338                         case ExpressionType.MultiplyChecked:
 339                                 if (IsInt32OrInt64 (left.Type))
 340                                         ig.Emit (OpCodes.Mul_Ovf);
 341                                 else
 342                                         ig.Emit (is_unsigned ? OpCodes.Mul_Ovf_Un : OpCodes.Mul);
 343                                 break;
 344                         case ExpressionType.Divide:
 345                                 ig.Emit (is_unsigned ? OpCodes.Div_Un : OpCodes.Div);
 346                                 break;
 347                         case ExpressionType.Modulo:
 348                                 ig.Emit (is_unsigned ? OpCodes.Rem_Un : OpCodes.Rem);
 349                                 break;
 350                         case ExpressionType.RightShift:
 351                                 ig.Emit (is_unsigned ? OpCodes.Shr_Un : OpCodes.Shr);
 352                                 break;
 353                         case ExpressionType.LeftShift:
 354                                 ig.Emit (OpCodes.Shl);
 355                                 break;
 356                         case ExpressionType.And:
 357                                 ig.Emit (OpCodes.And);
 358                                 break;
 359                         case ExpressionType.Or:
 360                                 ig.Emit (OpCodes.Or);
 361                                 break;
 362                         case ExpressionType.ExclusiveOr:
 363                                 ig.Emit (OpCodes.Xor);
 364                                 break;
 365                         case ExpressionType.GreaterThan:
 366                                 ig.Emit (is_unsigned ? OpCodes.Cgt_Un : OpCodes.Cgt);
 367                                 break;
 368                         case ExpressionType.GreaterThanOrEqual:
 369                                 if (is_unsigned || IsSingleOrDouble (left.Type))
 370                                         ig.Emit (OpCodes.Clt_Un);
 371                                 else
 372                                         ig.Emit (OpCodes.Clt);
 373
 374                                 ig.Emit (OpCodes.Ldc_I4_0);
 375                                 ig.Emit (OpCodes.Ceq);
 376                                 break;
 377                         case ExpressionType.LessThan:
 378                                 ig.Emit (is_unsigned ? OpCodes.Clt_Un : OpCodes.Clt);
 379                                 break;
 380                         case ExpressionType.LessThanOrEqual:
 381                                 if (is_unsigned || IsSingleOrDouble (left.Type))
 382                                         ig.Emit (OpCodes.Cgt_Un);
 383                                 else
 384                                         ig.Emit (OpCodes.Cgt);
 385
 386                                 ig.Emit (OpCodes.Ldc_I4_0);
 387                                 ig.Emit (OpCodes.Ceq);
 388                                 break;
 389                         case ExpressionType.Equal:
 390                                 ig.Emit (OpCodes.Ceq);
 391                                 break;
 392                         case ExpressionType.NotEqual:
 393                                 ig.Emit (OpCodes.Ceq);
 394                                 ig.Emit (OpCodes.Ldc_I4_0);
 395                                 ig.Emit (OpCodes.Ceq);
 396                                 break;
 397                         case ExpressionType.Power:
 398                                 ig.Emit (OpCodes.Call, typeof (Math).GetMethod ("Pow"));
 399                                 break;
 400                         default:
 401                                 throw new InvalidOperationException (
 402                                         string.Format ("Internal error: BinaryExpression contains non-Binary nodetype {0}", NodeType));
 403                         }
 404                 }
 405
 406                 bool IsLeftLiftedBinary ()
 407                 {
 408                         return left.Type.IsNullable () && !right.Type.IsNullable ();
 409                 }
 410
 411                 void EmitLeftLiftedToNullBinary (EmitContext ec)
 412                 {
 413                         var ig = ec.ig;
 414
 415                         var ret = ig.DefineLabel ();
 416                         var done = ig.DefineLabel ();
 417
 418                         var left = ec.EmitStored (this.left);
 419
 420                         ec.EmitNullableHasValue (left);
 421                         ig.Emit (OpCodes.Brfalse, ret);
 422
 423                         ec.EmitNullableGetValueOrDefault (left);
 424                         ec.Emit (right);
 425
 426                         EmitBinaryOperator (ec);
 427
 428                         ec.EmitNullableNew (Type);
 429
 430                         ig.Emit (OpCodes.Br, done);
 431
 432                         ig.MarkLabel (ret);
 433
 434                         var temp = ig.DeclareLocal (Type);
 435                         ec.EmitNullableInitialize (temp);
 436
 437                         ig.MarkLabel (done);
 438                 }
 439
 440                 void EmitLiftedArithmeticBinary (EmitContext ec)
 441                 {
 442                         if (IsLeftLiftedBinary ())
 443                                 EmitLeftLiftedToNullBinary (ec);
 444                         else
 445                                 EmitLiftedToNullBinary (ec);
 446                 }
 447
 448                 void EmitLiftedToNullBinary (EmitContext ec)
 449                 {
 450                         var ig = ec.ig;
 451                         var left = ec.EmitStored (this.left);
 452                         var right = ec.EmitStored (this.right);
 453                         var result = ig.DeclareLocal (Type);
 454
 455                         var has_value = ig.DefineLabel ();
 456                         var done = ig.DefineLabel ();
 457
 458                         ec.EmitNullableHasValue (left);
 459                         ec.EmitNullableHasValue (right);
 460                         ig.Emit (OpCodes.And);
 461                         ig.Emit (OpCodes.Brtrue, has_value);
 462
 463                         ec.EmitNullableInitialize (result);
 464
 465                         ig.Emit (OpCodes.Br, done);
 466
 467                         ig.MarkLabel (has_value);
 468
 469                         ec.EmitNullableGetValueOrDefault (left);
 470                         ec.EmitNullableGetValueOrDefault (right);
 471
 472                         EmitBinaryOperator (ec);
 473
 474                         ec.EmitNullableNew (result.LocalType);
 475
 476                         ig.MarkLabel (done);
 477                 }
 478
 479                 void EmitLiftedRelationalBinary (EmitContext ec)
 480                 {
 481                         var ig = ec.ig;
 482                         var left = ec.EmitStored (this.left);
 483                         var right = ec.EmitStored (this.right);
 484
 485                         var ret = ig.DefineLabel ();
 486                         var done = ig.DefineLabel ();
 487
 488                         ec.EmitNullableGetValueOrDefault (left);
 489                         ec.EmitNullableGetValueOrDefault (right);
 490
 491                         switch (NodeType) {
 492                         case ExpressionType.Equal:
 493                         case ExpressionType.NotEqual:
 494                                 ig.Emit (OpCodes.Bne_Un, ret);
 495                                 break;
 496                         default:
 497                                 EmitBinaryOperator (ec);
 498                                 ig.Emit (OpCodes.Brfalse, ret);
 499                                 break;
 500                         }
 501
 502                         ec.EmitNullableHasValue (left);
 503                         ec.EmitNullableHasValue (right);
 504
 505                         switch (NodeType) {
 506                         case ExpressionType.Equal:
 507                                 ig.Emit (OpCodes.Ceq);
 508                                 break;
 509                         case ExpressionType.NotEqual:
 510                                 ig.Emit (OpCodes.Ceq);
 511                                 ig.Emit (OpCodes.Ldc_I4_0);
 512                                 ig.Emit (OpCodes.Ceq);
 513                                 break;
 514                         default:
 515                                 ig.Emit (OpCodes.And);
 516                                 break;
 517                         }
 518
 519                         ig.Emit (OpCodes.Br, done);
 520
 521                         ig.MarkLabel (ret);
 522
 523                         ig.Emit (NodeType == ExpressionType.NotEqual ? OpCodes.Ldc_I4_1 : OpCodes.Ldc_I4_0);
 524
 525                         ig.MarkLabel (done);
 526                 }
 527
 528                 void EmitArithmeticBinary (EmitContext ec)
 529                 {
 530                         if (!IsLifted)
 531                                 EmitNonLiftedBinary (ec);
 532                         else
 533                                 EmitLiftedArithmeticBinary (ec);
 534                 }
 535
 536                 void EmitNonLiftedBinary (EmitContext ec)
 537                 {
 538                         ec.Emit (left);
 539                         ec.Emit (right);
 540                         EmitBinaryOperator (ec);
 541                 }
 542
 543                 void EmitRelationalBinary (EmitContext ec)
 544                 {
 545                         if (!IsLifted)
 546                                 EmitNonLiftedBinary (ec);
 547                         else if (IsLiftedToNull)
 548                                 EmitLiftedToNullBinary (ec);
 549                         else
 550                                 EmitLiftedRelationalBinary (ec);
 551                 }
 552
 553                 void EmitLiftedUserDefinedOperator (EmitContext ec)
 554                 {
 555                         var ig = ec.ig;
 556
 557                         var ret_true = ig.DefineLabel ();
 558                         var ret_false = ig.DefineLabel ();
 559                         var done = ig.DefineLabel ();
 560
 561                         var left = ec.EmitStored (this.left);
 562                         var right = ec.EmitStored (this.right);
 563
 564                         ec.EmitNullableHasValue (left);
 565                         ec.EmitNullableHasValue (right);
 566                         switch (NodeType) {
 567                         case ExpressionType.Equal:
 568                                 ig.Emit (OpCodes.Bne_Un, ret_false);
 569                                 ec.EmitNullableHasValue (left);
 570                                 ig.Emit (OpCodes.Brfalse, ret_true);
 571                                 break;
 572                         case ExpressionType.NotEqual:
 573                                 ig.Emit (OpCodes.Bne_Un, ret_true);
 574                                 ec.EmitNullableHasValue (left);
 575                                 ig.Emit (OpCodes.Brfalse, ret_false);
 576                                 break;
 577                         default:
 578                                 ig.Emit (OpCodes.And);
 579                                 ig.Emit (OpCodes.Brfalse, ret_false);
 580                                 break;
 581                         }
 582
 583                         ec.EmitNullableGetValueOrDefault (left);
 584                         ec.EmitNullableGetValueOrDefault (right);
 585                         ec.EmitCall (method);
 586                         ig.Emit (OpCodes.Br, done);
 587
 588                         ig.MarkLabel (ret_true);
 589                         ig.Emit (OpCodes.Ldc_I4_1);
 590                         ig.Emit (OpCodes.Br, done);
 591
 592                         ig.MarkLabel (ret_false);
 593                         ig.Emit (OpCodes.Ldc_I4_0);
 594                         ig.Emit (OpCodes.Br, done);
 595
 596                         ig.MarkLabel (done);
 597                 }
 598
 599                 void EmitLiftedToNullUserDefinedOperator (EmitContext ec)
 600                 {
 601                         var ig = ec.ig;
 602
 603                         var ret = ig.DefineLabel ();
 604                         var done = ig.DefineLabel ();
 605
 606                         var left = ec.EmitStored (this.left);
 607                         var right = ec.EmitStored (this.right);
 608
 609                         ec.EmitNullableHasValue (left);
 610                         ec.EmitNullableHasValue (right);
 611                         ig.Emit (OpCodes.And);
 612                         ig.Emit (OpCodes.Brfalse, ret);
 613
 614                         ec.EmitNullableGetValueOrDefault (left);
 615                         ec.EmitNullableGetValueOrDefault (right);
 616                         ec.EmitCall (method);
 617                         ec.EmitNullableNew (Type);
 618                         ig.Emit (OpCodes.Br, done);
 619
 620                         ig.MarkLabel (ret);
 621                         var temp = ig.DeclareLocal (Type);
 622                         ec.EmitNullableInitialize (temp);
 623
 624                         ig.MarkLabel (done);
 625                 }
 626
 627                 void EmitUserDefinedLiftedLogicalShortCircuit (EmitContext ec)
 628                 {
 629                         throw new NotImplementedException ();
 630                 }
 631
 632                 void EmitUserDefinedOperator (EmitContext ec)
 633                 {
 634                         if (!IsLifted) {
 635                                 switch (NodeType) {
 636                                 case ExpressionType.AndAlso:
 637                                 case ExpressionType.OrElse:
 638                                         EmitUserDefinedLogicalShortCircuit (ec);
 639                                         break;
 640                                 default:
 641                                         left.Emit (ec);
 642                                         right.Emit (ec);
 643                                         ec.EmitCall (method);
 644                                         break;
 645                                 }
 646                         } else if (IsLiftedToNull) {
 647                                 switch (NodeType) {
 648                                 case ExpressionType.AndAlso:
 649                                 case ExpressionType.OrElse:
 650                                         EmitUserDefinedLiftedLogicalShortCircuit (ec);
 651                                         break;
 652                                 default:
 653                                         EmitLiftedToNullUserDefinedOperator (ec);
 654                                         break;
 655                                 }
 656                         }  else
 657                                 EmitLiftedUserDefinedOperator (ec);
 658                 }
 659
 660                 internal override void Emit (EmitContext ec)
 661                 {
 662                         if (method != null){
 663                                 EmitUserDefinedOperator (ec);
 664                                 return;
 665                         }
 666
 667                         switch (NodeType){
 668                         case ExpressionType.ArrayIndex:
 669                                 EmitArrayAccess (ec);
 670                                 return;
 671                         case ExpressionType.Coalesce:
 672                                 if (conversion != null)
 673                                         EmitConvertedCoalesce (ec);
 674                                 else
 675                                         EmitCoalesce (ec);
 676                                 return;
 677                         case ExpressionType.Power:
 678                         case ExpressionType.Add:
 679                         case ExpressionType.AddChecked:
 680                         case ExpressionType.Divide:
 681                         case ExpressionType.ExclusiveOr:
 682                         case ExpressionType.LeftShift:
 683                         case ExpressionType.Modulo:
 684                         case ExpressionType.Multiply:
 685                         case ExpressionType.MultiplyChecked:
 686                         case ExpressionType.RightShift:
 687                         case ExpressionType.Subtract:
 688                         case ExpressionType.SubtractChecked:
 689                                 EmitArithmeticBinary (ec);
 690                                 return;
 691                         case ExpressionType.Equal:
 692                         case ExpressionType.GreaterThan:
 693                         case ExpressionType.GreaterThanOrEqual:
 694                         case ExpressionType.LessThan:
 695                         case ExpressionType.LessThanOrEqual:
 696                         case ExpressionType.NotEqual:
 697                                 EmitRelationalBinary (ec);
 698                                 return;
 699                         case ExpressionType.And:
 700                         case ExpressionType.Or:
 701                         case ExpressionType.AndAlso:
 702                         case ExpressionType.OrElse:
 703                                 EmitLogicalBinary (ec);
 704                                 return;
 705                         default:
 706                                 throw new NotSupportedException (this.NodeType.ToString ());
 707                         }
 708                 }
 709         }
 710 }