mcs/mcs/expression.cs

   1 //
   2 // expression.cs: Expression representation for the IL tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2001 Ximian, Inc.
   8 //
   9 //
  10 #define USE_OLD
  11
  12 namespace Mono.CSharp {
  13         using System;
  14         using System.Collections;
  15         using System.Reflection;
  16         using System.Reflection.Emit;
  17         using System.Text;
  18
  19         /// <summary>
  20         ///   This is just a helper class, it is generated by Unary, UnaryMutator
  21         ///   when an overloaded method has been found.  It just emits the code for a
  22         ///   static call.
  23         /// </summary>
  24         public class StaticCallExpr : ExpressionStatement {
  25                 ArrayList args;
  26                 MethodInfo mi;
  27
  28                 StaticCallExpr (MethodInfo m, ArrayList a, Location l)
  29                 {
  30                         mi = m;
  31                         args = a;
  32
  33                         type = m.ReturnType;
  34                         eclass = ExprClass.Value;
  35                         loc = l;
  36                 }
  37
  38                 public override Expression DoResolve (EmitContext ec)
  39                 {
  40                         //
  41                         // We are born fully resolved
  42                         //
  43                         return this;
  44                 }
  45
  46                 public override void Emit (EmitContext ec)
  47                 {
  48                         if (args != null)
  49                                 Invocation.EmitArguments (ec, mi, args);
  50
  51                         ec.ig.Emit (OpCodes.Call, mi);
  52                         return;
  53                 }
  54
  55                 static public Expression MakeSimpleCall (EmitContext ec, MethodGroupExpr mg,
  56                                                          Expression e, Location loc)
  57                 {
  58                         ArrayList args;
  59                         MethodBase method;
  60
  61                         args = new ArrayList (1);
  62                         args.Add (new Argument (e, Argument.AType.Expression));
  63                         method = Invocation.OverloadResolve (ec, (MethodGroupExpr) mg, args, loc);
  64
  65                         if (method == null)
  66                                 return null;
  67
  68                         return new StaticCallExpr ((MethodInfo) method, args, loc);
  69                 }
  70
  71                 public override void EmitStatement (EmitContext ec)
  72                 {
  73                         Emit (ec);
  74                         if (TypeManager.TypeToCoreType (type) != TypeManager.void_type)
  75                                 ec.ig.Emit (OpCodes.Pop);
  76                 }
  77         }
  78
  79         /// <summary>
  80         ///   Unary expressions.
  81         /// </summary>
  82         ///
  83         /// <remarks>
  84         ///   Unary implements unary expressions.   It derives from
  85         ///   ExpressionStatement becuase the pre/post increment/decrement
  86         ///   operators can be used in a statement context.
  87         /// </remarks>
  88         public class Unary : Expression {
  89                 public enum Operator : byte {
  90                         UnaryPlus, UnaryNegation, LogicalNot, OnesComplement,
  91                         Indirection, AddressOf,  TOP
  92                 }
  93
  94                 public Operator Oper;
  95                 public Expression Expr;
  96
  97                 public Unary (Operator op, Expression expr, Location loc)
  98                 {
  99                         this.Oper = op;
 100                         this.Expr = expr;
 101                         this.loc = loc;
 102                 }
 103
 104                 /// <summary>
 105                 ///   Returns a stringified representation of the Operator
 106                 /// </summary>
 107                 static public string OperName (Operator oper)
 108                 {
 109                         switch (oper){
 110                         case Operator.UnaryPlus:
 111                                 return "+";
 112                         case Operator.UnaryNegation:
 113                                 return "-";
 114                         case Operator.LogicalNot:
 115                                 return "!";
 116                         case Operator.OnesComplement:
 117                                 return "~";
 118                         case Operator.AddressOf:
 119                                 return "&";
 120                         case Operator.Indirection:
 121                                 return "*";
 122                         }
 123
 124                         return oper.ToString ();
 125                 }
 126
 127                 static string [] oper_names;
 128
 129                 static Unary ()
 130                 {
 131                         oper_names = new string [(int)Operator.TOP];
 132
 133                         oper_names [(int) Operator.UnaryPlus] = "op_UnaryPlus";
 134                         oper_names [(int) Operator.UnaryNegation] = "op_UnaryNegation";
 135                         oper_names [(int) Operator.LogicalNot] = "op_LogicalNot";
 136                         oper_names [(int) Operator.OnesComplement] = "op_OnesComplement";
 137                         oper_names [(int) Operator.Indirection] = "op_Indirection";
 138                         oper_names [(int) Operator.AddressOf] = "op_AddressOf";
 139                 }
 140
 141                 void Error23 (Type t)
 142                 {
 143                         Error (
 144                                 23, "Operator " + OperName (Oper) +
 145                                 " cannot be applied to operand of type `" +
 146                                 TypeManager.CSharpName (t) + "'");
 147                 }
 148
 149                 /// <remarks>
 150                 ///   The result has been already resolved:
 151                 ///
 152                 ///   FIXME: a minus constant -128 sbyte cant be turned into a
 153                 ///   constant byte.
 154                 /// </remarks>
 155                 static Expression TryReduceNegative (Constant expr)
 156                 {
 157                         Expression e = null;
 158
 159                         if (expr is IntConstant)
 160                                 e = new IntConstant (-((IntConstant) expr).Value);
 161                         else if (expr is UIntConstant){
 162                                 uint value = ((UIntConstant) expr).Value;
 163
 164                                 if (value < 2147483649)
 165                                         return new IntConstant (-(int)value);
 166                                 else
 167                                         e = new LongConstant (value);
 168                         }
 169                         else if (expr is LongConstant)
 170                                 e = new LongConstant (-((LongConstant) expr).Value);
 171                         else if (expr is ULongConstant){
 172                                 ulong value = ((ULongConstant) expr).Value;
 173
 174                                 if (value < 9223372036854775809)
 175                                         return new LongConstant(-(long)value);
 176                         }
 177                         else if (expr is FloatConstant)
 178                                 e = new FloatConstant (-((FloatConstant) expr).Value);
 179                         else if (expr is DoubleConstant)
 180                                 e = new DoubleConstant (-((DoubleConstant) expr).Value);
 181                         else if (expr is DecimalConstant)
 182                                 e = new DecimalConstant (-((DecimalConstant) expr).Value);
 183                         else if (expr is ShortConstant)
 184                                 e = new IntConstant (-((ShortConstant) expr).Value);
 185                         else if (expr is UShortConstant)
 186                                 e = new IntConstant (-((UShortConstant) expr).Value);
 187                         return e;
 188                 }
 189
 190                 // <summary>
 191                 //   This routine will attempt to simplify the unary expression when the
 192                 //   argument is a constant.  The result is returned in `result' and the
 193                 //   function returns true or false depending on whether a reduction
 194                 //   was performed or not
 195                 // </summary>
 196                 bool Reduce (EmitContext ec, Constant e, out Expression result)
 197                 {
 198                         Type expr_type = e.Type;
 199
 200                         switch (Oper){
 201                         case Operator.UnaryPlus:
 202                                 result = e;
 203                                 return true;
 204
 205                         case Operator.UnaryNegation:
 206                                 result = TryReduceNegative (e);
 207                                 return true;
 208
 209                         case Operator.LogicalNot:
 210                                 if (expr_type != TypeManager.bool_type) {
 211                                         result = null;
 212                                         Error23 (expr_type);
 213                                         return false;
 214                                 }
 215
 216                                 BoolConstant b = (BoolConstant) e;
 217                                 result = new BoolConstant (!(b.Value));
 218                                 return true;
 219
 220                         case Operator.OnesComplement:
 221                                 if (!((expr_type == TypeManager.int32_type) ||
 222                                       (expr_type == TypeManager.uint32_type) ||
 223                                       (expr_type == TypeManager.int64_type) ||
 224                                       (expr_type == TypeManager.uint64_type) ||
 225                                       (expr_type.IsSubclassOf (TypeManager.enum_type)))){
 226                                         result = null;
 227                                         Error23 (expr_type);
 228                                         return false;
 229                                 }
 230
 231                                 if (e is EnumConstant){
 232                                         EnumConstant enum_constant = (EnumConstant) e;
 233                                         Expression reduced;
 234
 235                                         if (Reduce (ec, enum_constant.Child, out reduced)){
 236                                                 result = new EnumConstant ((Constant) reduced, enum_constant.Type);
 237                                                 return true;
 238                                         } else {
 239                                                 result = null;
 240                                                 return false;
 241                                         }
 242                                 }
 243
 244                                 if (expr_type == TypeManager.int32_type){
 245                                         result = new IntConstant (~ ((IntConstant) e).Value);
 246                                 } else if (expr_type == TypeManager.uint32_type){
 247                                         result = new UIntConstant (~ ((UIntConstant) e).Value);
 248                                 } else if (expr_type == TypeManager.int64_type){
 249                                         result = new LongConstant (~ ((LongConstant) e).Value);
 250                                 } else if (expr_type == TypeManager.uint64_type){
 251                                         result = new ULongConstant (~ ((ULongConstant) e).Value);
 252                                 } else {
 253                                         result = null;
 254                                         Error23 (expr_type);
 255                                         return false;
 256                                 }
 257                                 return true;
 258
 259                         case Operator.AddressOf:
 260                                 result = this;
 261                                 return false;
 262
 263                         case Operator.Indirection:
 264                                 result = this;
 265                                 return false;
 266                         }
 267                         throw new Exception ("Can not constant fold: " + Oper.ToString());
 268                 }
 269
 270                 Expression ResolveOperator (EmitContext ec)
 271                 {
 272                         Type expr_type = Expr.Type;
 273
 274                         //
 275                         // Step 1: Perform Operator Overload location
 276                         //
 277                         Expression mg;
 278                         string op_name;
 279
 280                         op_name = oper_names [(int) Oper];
 281
 282                         mg = MemberLookup (ec, expr_type, op_name, MemberTypes.Method, AllBindingFlags, loc);
 283
 284                         if (mg != null) {
 285                                 Expression e = StaticCallExpr.MakeSimpleCall (
 286                                         ec, (MethodGroupExpr) mg, Expr, loc);
 287
 288                                 if (e == null){
 289                                         Error23 (expr_type);
 290                                         return null;
 291                                 }
 292
 293                                 return e;
 294                         }
 295
 296                         // Only perform numeric promotions on:
 297                         // +, -
 298
 299                         if (expr_type == null)
 300                                 return null;
 301
 302                         //
 303                         // Step 2: Default operations on CLI native types.
 304                         //
 305
 306                         // Attempt to use a constant folding operation.
 307                         if (Expr is Constant){
 308                                 Expression result;
 309
 310                                 if (Reduce (ec, (Constant) Expr, out result))
 311                                         return result;
 312                         }
 313
 314                         switch (Oper){
 315                         case Operator.LogicalNot:
 316                                 if (expr_type != TypeManager.bool_type) {
 317                                         Error23 (Expr.Type);
 318                                         return null;
 319                                 }
 320
 321                                 type = TypeManager.bool_type;
 322                                 return this;
 323
 324                         case Operator.OnesComplement:
 325                                 if (!((expr_type == TypeManager.int32_type) ||
 326                                       (expr_type == TypeManager.uint32_type) ||
 327                                       (expr_type == TypeManager.int64_type) ||
 328                                       (expr_type == TypeManager.uint64_type) ||
 329                                       (expr_type.IsSubclassOf (TypeManager.enum_type)))){
 330                                         Expression e;
 331
 332                                         e = ConvertImplicit (ec, Expr, TypeManager.int32_type, loc);
 333                                         if (e != null){
 334                                                 type = TypeManager.int32_type;
 335                                                 return this;
 336                                         }
 337                                         e = ConvertImplicit (ec, Expr, TypeManager.uint32_type, loc);
 338                                         if (e != null){
 339                                                 type = TypeManager.uint32_type;
 340                                                 return this;
 341                                         }
 342                                         e = ConvertImplicit (ec, Expr, TypeManager.int64_type, loc);
 343                                         if (e != null){
 344                                                 type = TypeManager.int64_type;
 345                                                 return this;
 346                                         }
 347                                         e = ConvertImplicit (ec, Expr, TypeManager.uint64_type, loc);
 348                                         if (e != null){
 349                                                 type = TypeManager.uint64_type;
 350                                                 return this;
 351                                         }
 352                                         Error23 (expr_type);
 353                                         return null;
 354                                 }
 355                                 type = expr_type;
 356                                 return this;
 357
 358                         case Operator.AddressOf:
 359                                 if (Expr.eclass != ExprClass.Variable){
 360                                         Error (211, "Cannot take the address of non-variables");
 361                                         return null;
 362                                 }
 363
 364                                 if (!ec.InUnsafe) {
 365                                         UnsafeError (loc);
 366                                         return null;
 367                                 }
 368
 369                                 if (!TypeManager.VerifyUnManaged (Expr.Type, loc)){
 370                                         return null;
 371                                 }
 372
 373                                 string ptr_type_name = Expr.Type.FullName + "*";
 374                                 type = TypeManager.LookupType (ptr_type_name);
 375
 376                                 return this;
 377
 378                         case Operator.Indirection:
 379                                 if (!ec.InUnsafe){
 380                                         UnsafeError (loc);
 381                                         return null;
 382                                 }
 383
 384                                 if (!expr_type.IsPointer){
 385                                         Error (
 386                                                 193,
 387                                                 "The * or -> operator can only be applied to pointers");
 388                                         return null;
 389                                 }
 390
 391                                 //
 392                                 // We create an Indirection expression, because
 393                                 // it can implement the IMemoryLocation.
 394                                 //
 395                                 return new Indirection (Expr, loc);
 396
 397                         case Operator.UnaryPlus:
 398                                 //
 399                                 // A plus in front of something is just a no-op, so return the child.
 400                                 //
 401                                 return Expr;
 402
 403                         case Operator.UnaryNegation:
 404                                 //
 405                                 // Deals with -literals
 406                                 // int     operator- (int x)
 407                                 // long    operator- (long x)
 408                                 // float   operator- (float f)
 409                                 // double  operator- (double d)
 410                                 // decimal operator- (decimal d)
 411                                 //
 412                                 Expression expr = null;
 413
 414                                 //
 415                                 // transform - - expr into expr
 416                                 //
 417                                 if (Expr is Unary){
 418                                         Unary unary = (Unary) Expr;
 419
 420                                         if (unary.Oper == Operator.UnaryNegation)
 421                                                 return unary.Expr;
 422                                 }
 423
 424                                 //
 425                                 // perform numeric promotions to int,
 426                                 // long, double.
 427                                 //
 428                                 //
 429                                 // The following is inneficient, because we call
 430                                 // ConvertImplicit too many times.
 431                                 //
 432                                 // It is also not clear if we should convert to Float
 433                                 // or Double initially.
 434                                 //
 435                                 if (expr_type == TypeManager.uint32_type){
 436                                         //
 437                                         // FIXME: handle exception to this rule that
 438                                         // permits the int value -2147483648 (-2^31) to
 439                                         // bt wrote as a decimal interger literal
 440                                         //
 441                                         type = TypeManager.int64_type;
 442                                         Expr = ConvertImplicit (ec, Expr, type, loc);
 443                                         return this;
 444                                 }
 445
 446                                 if (expr_type == TypeManager.uint64_type){
 447                                         //
 448                                         // FIXME: Handle exception of `long value'
 449                                         // -92233720368547758087 (-2^63) to be wrote as
 450                                         // decimal integer literal.
 451                                         //
 452                                         Error23 (expr_type);
 453                                         return null;
 454                                 }
 455
 456                                 if (expr_type == TypeManager.float_type){
 457                                         type = expr_type;
 458                                         return this;
 459                                 }
 460
 461                                 expr = ConvertImplicit (ec, Expr, TypeManager.int32_type, loc);
 462                                 if (expr != null){
 463                                         Expr = expr;
 464                                         type = expr.Type;
 465                                         return this;
 466                                 }
 467
 468                                 expr = ConvertImplicit (ec, Expr, TypeManager.int64_type, loc);
 469                                 if (expr != null){
 470                                         Expr = expr;
 471                                         type = expr.Type;
 472                                         return this;
 473                                 }
 474
 475                                 expr = ConvertImplicit (ec, Expr, TypeManager.double_type, loc);
 476                                 if (expr != null){
 477                                         Expr = expr;
 478                                         type = expr.Type;
 479                                         return this;
 480                                 }
 481
 482                                 Error23 (expr_type);
 483                                 return null;
 484                         }
 485
 486                         Error (187, "No such operator '" + OperName (Oper) + "' defined for type '" +
 487                                TypeManager.CSharpName (expr_type) + "'");
 488                         return null;
 489                 }
 490
 491                 public override Expression DoResolve (EmitContext ec)
 492                 {
 493                         if (Oper == Operator.AddressOf)
 494                                 Expr = Expr.ResolveLValue (ec, new EmptyExpression ());
 495                         else
 496                                 Expr = Expr.Resolve (ec);
 497
 498                         if (Expr == null)
 499                                 return null;
 500
 501                         eclass = ExprClass.Value;
 502                         return ResolveOperator (ec);
 503                 }
 504
 505                 public override void Emit (EmitContext ec)
 506                 {
 507                         ILGenerator ig = ec.ig;
 508                         Type expr_type = Expr.Type;
 509
 510                         switch (Oper) {
 511                         case Operator.UnaryPlus:
 512                                 throw new Exception ("This should be caught by Resolve");
 513
 514                         case Operator.UnaryNegation:
 515                                 Expr.Emit (ec);
 516                                 ig.Emit (OpCodes.Neg);
 517                                 break;
 518
 519                         case Operator.LogicalNot:
 520                                 Expr.Emit (ec);
 521                                 ig.Emit (OpCodes.Ldc_I4_0);
 522                                 ig.Emit (OpCodes.Ceq);
 523                                 break;
 524
 525                         case Operator.OnesComplement:
 526                                 Expr.Emit (ec);
 527                                 ig.Emit (OpCodes.Not);
 528                                 break;
 529
 530                         case Operator.AddressOf:
 531                                 ((IMemoryLocation)Expr).AddressOf (ec, AddressOp.LoadStore);
 532                                 break;
 533
 534                         default:
 535                                 throw new Exception ("This should not happen: Operator = "
 536                                                      + Oper.ToString ());
 537                         }
 538                 }
 539
 540                 /// <summary>
 541                 ///   This will emit the child expression for `ec' avoiding the logical
 542                 ///   not.  The parent will take care of changing brfalse/brtrue
 543                 /// </summary>
 544                 public void EmitLogicalNot (EmitContext ec)
 545                 {
 546                         if (Oper != Operator.LogicalNot)
 547                                 throw new Exception ("EmitLogicalNot can only be called with !expr");
 548
 549                         Expr.Emit (ec);
 550                 }
 551
 552                 public override string ToString ()
 553                 {
 554                         return "Unary (" + Oper + ", " + Expr + ")";
 555                 }
 556
 557         }
 558
 559         //
 560         // Unary operators are turned into Indirection expressions
 561         // after semantic analysis (this is so we can take the address
 562         // of an indirection).
 563         //
 564         public class Indirection : Expression, IMemoryLocation, IAssignMethod {
 565                 Expression expr;
 566                 LocalTemporary temporary;
 567                 bool have_temporary;
 568
 569                 public Indirection (Expression expr, Location l)
 570                 {
 571                         this.expr = expr;
 572                         this.type = TypeManager.TypeToCoreType (expr.Type.GetElementType ());
 573                         eclass = ExprClass.Variable;
 574                         loc = l;
 575                 }
 576
 577                 void LoadExprValue (EmitContext ec)
 578                 {
 579                 }
 580
 581                 public override void Emit (EmitContext ec)
 582                 {
 583                         ILGenerator ig = ec.ig;
 584
 585                         if (temporary != null){
 586                                 if (have_temporary){
 587                                         temporary.Emit (ec);
 588                                         return;
 589                                 }
 590                                 expr.Emit (ec);
 591                                 ec.ig.Emit (OpCodes.Dup);
 592                                 temporary.Store (ec);
 593                                 have_temporary = true;
 594                         } else
 595                                 expr.Emit (ec);
 596
 597                         LoadFromPtr (ig, Type);
 598                 }
 599
 600                 public void EmitAssign (EmitContext ec, Expression source)
 601                 {
 602                         if (temporary != null){
 603                                 if (have_temporary){
 604                                         temporary.Emit (ec);
 605                                         return;
 606                                 }
 607                                 expr.Emit (ec);
 608                                 ec.ig.Emit (OpCodes.Dup);
 609                                 temporary.Store (ec);
 610                                 have_temporary = true;
 611                         } else
 612                                 expr.Emit (ec);
 613
 614                         source.Emit (ec);
 615                         StoreFromPtr (ec.ig, type);
 616                 }
 617
 618                 public void AddressOf (EmitContext ec, AddressOp Mode)
 619                 {
 620                         if (temporary != null){
 621                                 if (have_temporary){
 622                                         temporary.Emit (ec);
 623                                         return;
 624                                 }
 625                                 expr.Emit (ec);
 626                                 ec.ig.Emit (OpCodes.Dup);
 627                                 temporary.Store (ec);
 628                                 have_temporary = true;
 629                         } else
 630                                 expr.Emit (ec);
 631                 }
 632
 633                 public override Expression DoResolve (EmitContext ec)
 634                 {
 635                         //
 636                         // Born fully resolved
 637                         //
 638                         return this;
 639                 }
 640
 641                 public new void CacheTemporaries (EmitContext ec)
 642                 {
 643                         temporary = new LocalTemporary (ec, type);
 644                 }
 645         }
 646
 647         /// <summary>
 648         ///   Unary Mutator expressions (pre and post ++ and --)
 649         /// </summary>
 650         ///
 651         /// <remarks>
 652         ///   UnaryMutator implements ++ and -- expressions.   It derives from
 653         ///   ExpressionStatement becuase the pre/post increment/decrement
 654         ///   operators can be used in a statement context.
 655         ///
 656         /// FIXME: Idea, we could split this up in two classes, one simpler
 657         /// for the common case, and one with the extra fields for more complex
 658         /// classes (indexers require temporary access;  overloaded require method)
 659         ///
 660         /// Maybe we should have classes PreIncrement, PostIncrement, PreDecrement,
 661         /// PostDecrement, that way we could save the `Mode' byte as well.
 662         /// </remarks>
 663         public class UnaryMutator : ExpressionStatement {
 664                 public enum Mode : byte {
 665                         PreIncrement, PreDecrement, PostIncrement, PostDecrement
 666                 }
 667
 668                 Mode mode;
 669                 Expression expr;
 670                 LocalTemporary temp_storage;
 671
 672                 //
 673                 // This is expensive for the simplest case.
 674                 //
 675                 Expression method;
 676
 677                 public UnaryMutator (Mode m, Expression e, Location l)
 678                 {
 679                         mode = m;
 680                         loc = l;
 681                         expr = e;
 682                 }
 683
 684                 static string OperName (Mode mode)
 685                 {
 686                         return (mode == Mode.PreIncrement || mode == Mode.PostIncrement) ?
 687                                 "++" : "--";
 688                 }
 689
 690                 void Error23 (Type t)
 691                 {
 692                         Error (
 693                                 23, "Operator " + OperName (mode) +
 694                                 " cannot be applied to operand of type `" +
 695                                 TypeManager.CSharpName (t) + "'");
 696                 }
 697
 698                 /// <summary>
 699                 ///   Returns whether an object of type `t' can be incremented
 700                 ///   or decremented with add/sub (ie, basically whether we can
 701                 ///   use pre-post incr-decr operations on it, but it is not a
 702                 ///   System.Decimal, which we require operator overloading to catch)
 703                 /// </summary>
 704                 static bool IsIncrementableNumber (Type t)
 705                 {
 706                         return (t == TypeManager.sbyte_type) ||
 707                                 (t == TypeManager.byte_type) ||
 708                                 (t == TypeManager.short_type) ||
 709                                 (t == TypeManager.ushort_type) ||
 710                                 (t == TypeManager.int32_type) ||
 711                                 (t == TypeManager.uint32_type) ||
 712                                 (t == TypeManager.int64_type) ||
 713                                 (t == TypeManager.uint64_type) ||
 714                                 (t == TypeManager.char_type) ||
 715                                 (t.IsSubclassOf (TypeManager.enum_type)) ||
 716                                 (t == TypeManager.float_type) ||
 717                                 (t == TypeManager.double_type) ||
 718                                 (t.IsPointer && t != TypeManager.void_ptr_type);
 719                 }
 720
 721                 Expression ResolveOperator (EmitContext ec)
 722                 {
 723                         Type expr_type = expr.Type;
 724
 725                         //
 726                         // Step 1: Perform Operator Overload location
 727                         //
 728                         Expression mg;
 729                         string op_name;
 730
 731                         if (mode == Mode.PreIncrement || mode == Mode.PostIncrement)
 732                                 op_name = "op_Increment";
 733                         else
 734                                 op_name = "op_Decrement";
 735
 736                         mg = MemberLookup (ec, expr_type, op_name, MemberTypes.Method, AllBindingFlags, loc);
 737
 738                         if (mg == null && expr_type.BaseType != null)
 739                                 mg = MemberLookup (ec, expr_type.BaseType, op_name,
 740                                                    MemberTypes.Method, AllBindingFlags, loc);
 741
 742                         if (mg != null) {
 743                                 method = StaticCallExpr.MakeSimpleCall (
 744                                         ec, (MethodGroupExpr) mg, expr, loc);
 745
 746                                 type = method.Type;
 747                                 return this;
 748                         }
 749
 750                         //
 751                         // The operand of the prefix/postfix increment decrement operators
 752                         // should be an expression that is classified as a variable,
 753                         // a property access or an indexer access
 754                         //
 755                         type = expr_type;
 756                         if (expr.eclass == ExprClass.Variable){
 757                                 if (IsIncrementableNumber (expr_type) ||
 758                                     expr_type == TypeManager.decimal_type){
 759                                         return this;
 760                                 }
 761                         } else if (expr.eclass == ExprClass.IndexerAccess){
 762                                 IndexerAccess ia = (IndexerAccess) expr;
 763
 764                                 temp_storage = new LocalTemporary (ec, expr.Type);
 765
 766                                 expr = ia.ResolveLValue (ec, temp_storage);
 767                                 if (expr == null)
 768                                         return null;
 769
 770                                 return this;
 771                         } else if (expr.eclass == ExprClass.PropertyAccess){
 772                                 PropertyExpr pe = (PropertyExpr) expr;
 773
 774                                 if (pe.VerifyAssignable ())
 775                                         return this;
 776
 777                                 return null;
 778                         } else {
 779                                 expr.Error118 ("variable, indexer or property access");
 780                                 return null;
 781                         }
 782
 783                         Error (187, "No such operator '" + OperName (mode) + "' defined for type '" +
 784                                TypeManager.CSharpName (expr_type) + "'");
 785                         return null;
 786                 }
 787
 788                 public override Expression DoResolve (EmitContext ec)
 789                 {
 790                         expr = expr.Resolve (ec);
 791
 792                         if (expr == null)
 793                                 return null;
 794
 795                         eclass = ExprClass.Value;
 796                         return ResolveOperator (ec);
 797                 }
 798
 799                 static int PtrTypeSize (Type t)
 800                 {
 801                         return GetTypeSize (t.GetElementType ());
 802                 }
 803
 804                 //
 805                 // Loads the proper "1" into the stack based on the type
 806                 //
 807                 static void LoadOne (ILGenerator ig, Type t)
 808                 {
 809                         if (t == TypeManager.uint64_type || t == TypeManager.int64_type)
 810                                 ig.Emit (OpCodes.Ldc_I8, 1L);
 811                         else if (t == TypeManager.double_type)
 812                                 ig.Emit (OpCodes.Ldc_R8, 1.0);
 813                         else if (t == TypeManager.float_type)
 814                                 ig.Emit (OpCodes.Ldc_R4, 1.0F);
 815                         else if (t.IsPointer){
 816                                 int n = PtrTypeSize (t);
 817
 818                                 if (n == 0)
 819                                         ig.Emit (OpCodes.Sizeof, t);
 820                                 else
 821                                         IntConstant.EmitInt (ig, n);
 822                         } else
 823                                 ig.Emit (OpCodes.Ldc_I4_1);
 824                 }
 825
 826
 827                 //
 828                 // FIXME: We need some way of avoiding the use of temp_storage
 829                 // for some types of storage (parameters, local variables,
 830                 // static fields) and single-dimension array access.
 831                 //
 832                 void EmitCode (EmitContext ec, bool is_expr)
 833                 {
 834                         ILGenerator ig = ec.ig;
 835                         IAssignMethod ia = (IAssignMethod) expr;
 836                         Type expr_type = expr.Type;
 837
 838                         if (temp_storage == null)
 839                                 temp_storage = new LocalTemporary (ec, expr_type);
 840
 841                         ia.CacheTemporaries (ec);
 842                         ig.Emit (OpCodes.Nop);
 843                         switch (mode){
 844                         case Mode.PreIncrement:
 845                         case Mode.PreDecrement:
 846                                 if (method == null){
 847                                         expr.Emit (ec);
 848
 849                                         LoadOne (ig, expr_type);
 850
 851                                         //
 852                                         // Select the opcode based on the check state (then the type)
 853                                         // and the actual operation
 854                                         //
 855                                         if (ec.CheckState){
 856                                                 if (expr_type == TypeManager.int32_type ||
 857                                                     expr_type == TypeManager.int64_type){
 858                                                         if (mode == Mode.PreDecrement)
 859                                                                 ig.Emit (OpCodes.Sub_Ovf);
 860                                                         else
 861                                                                 ig.Emit (OpCodes.Add_Ovf);
 862                                                 } else if (expr_type == TypeManager.uint32_type ||
 863                                                            expr_type == TypeManager.uint64_type){
 864                                                         if (mode == Mode.PreDecrement)
 865                                                                 ig.Emit (OpCodes.Sub_Ovf_Un);
 866                                                         else
 867                                                                 ig.Emit (OpCodes.Add_Ovf_Un);
 868                                                 } else {
 869                                                         if (mode == Mode.PreDecrement)
 870                                                                 ig.Emit (OpCodes.Sub_Ovf);
 871                                                         else
 872                                                                 ig.Emit (OpCodes.Add_Ovf);
 873                                                 }
 874                                         } else {
 875                                                 if (mode == Mode.PreDecrement)
 876                                                         ig.Emit (OpCodes.Sub);
 877                                                 else
 878                                                         ig.Emit (OpCodes.Add);
 879                                         }
 880                                 } else
 881                                         method.Emit (ec);
 882
 883                                 temp_storage.Store (ec);
 884                                 ia.EmitAssign (ec, temp_storage);
 885                                 if (is_expr)
 886                                         temp_storage.Emit (ec);
 887                                 break;
 888
 889                         case Mode.PostIncrement:
 890                         case Mode.PostDecrement:
 891                                 if (is_expr)
 892                                         expr.Emit (ec);
 893
 894                                 if (method == null){
 895                                         if (!is_expr)
 896                                                 expr.Emit (ec);
 897                                         else
 898                                                 ig.Emit (OpCodes.Dup);
 899
 900                                         LoadOne (ig, expr_type);
 901
 902                                         if (ec.CheckState){
 903                                                 if (expr_type == TypeManager.int32_type ||
 904                                                     expr_type == TypeManager.int64_type){
 905                                                         if (mode == Mode.PostDecrement)
 906                                                                 ig.Emit (OpCodes.Sub_Ovf);
 907                                                         else
 908                                                                 ig.Emit (OpCodes.Add_Ovf);
 909                                                 } else if (expr_type == TypeManager.uint32_type ||
 910                                                            expr_type == TypeManager.uint64_type){
 911                                                         if (mode == Mode.PostDecrement)
 912                                                                 ig.Emit (OpCodes.Sub_Ovf_Un);
 913                                                         else
 914                                                                 ig.Emit (OpCodes.Add_Ovf_Un);
 915                                                 } else {
 916                                                         if (mode == Mode.PostDecrement)
 917                                                                 ig.Emit (OpCodes.Sub_Ovf);
 918                                                         else
 919                                                                 ig.Emit (OpCodes.Add_Ovf);
 920                                                 }
 921                                         } else {
 922                                                 if (mode == Mode.PostDecrement)
 923                                                         ig.Emit (OpCodes.Sub);
 924                                                 else
 925                                                         ig.Emit (OpCodes.Add);
 926                                         }
 927                                 } else {
 928                                         method.Emit (ec);
 929                                 }
 930
 931                                 temp_storage.Store (ec);
 932                                 ia.EmitAssign (ec, temp_storage);
 933                                 break;
 934                         }
 935                 }
 936
 937                 public override void Emit (EmitContext ec)
 938                 {
 939                         EmitCode (ec, true);
 940
 941                 }
 942
 943                 public override void EmitStatement (EmitContext ec)
 944                 {
 945                         EmitCode (ec, false);
 946                 }
 947
 948         }
 949
 950         /// <summary>
 951         ///   Base class for the `Is' and `As' classes.
 952         /// </summary>
 953         ///
 954         /// <remarks>
 955         ///   FIXME: Split this in two, and we get to save the `Operator' Oper
 956         ///   size.
 957         /// </remarks>
 958         public abstract class Probe : Expression {
 959                 public readonly Expression ProbeType;
 960                 protected Expression expr;
 961                 protected Type probe_type;
 962
 963                 public Probe (Expression expr, Expression probe_type, Location l)
 964                 {
 965                         ProbeType = probe_type;
 966                         loc = l;
 967                         this.expr = expr;
 968                 }
 969
 970                 public Expression Expr {
 971                         get {
 972                                 return expr;
 973                         }
 974                 }
 975
 976                 public override Expression DoResolve (EmitContext ec)
 977                 {
 978                         probe_type = ec.DeclSpace.ResolveType (ProbeType, false, loc);
 979
 980                         if (probe_type == null)
 981                                 return null;
 982
 983                         expr = expr.Resolve (ec);
 984
 985                         return this;
 986                 }
 987         }
 988
 989         /// <summary>
 990         ///   Implementation of the `is' operator.
 991         /// </summary>
 992         public class Is : Probe {
 993                 public Is (Expression expr, Expression probe_type, Location l)
 994                         : base (expr, probe_type, l)
 995                 {
 996                 }
 997
 998                 enum Action {
 999                         AlwaysTrue, AlwaysNull, AlwaysFalse, LeaveOnStack, Probe
1000                 }
1001
1002                 Action action;
1003
1004                 public override void Emit (EmitContext ec)
1005                 {
1006                         ILGenerator ig = ec.ig;
1007
1008                         expr.Emit (ec);
1009
1010                         switch (action){
1011                         case Action.AlwaysFalse:
1012                                 ig.Emit (OpCodes.Pop);
1013                                 IntConstant.EmitInt (ig, 0);
1014                                 return;
1015                         case Action.AlwaysTrue:
1016                                 ig.Emit (OpCodes.Pop);
1017                                 ig.Emit (OpCodes.Nop);
1018                                 IntConstant.EmitInt (ig, 1);
1019                                 return;
1020                         case Action.LeaveOnStack:
1021                                 // the `e != null' rule.
1022                                 return;
1023                         case Action.Probe:
1024                                 ig.Emit (OpCodes.Isinst, probe_type);
1025                                 ig.Emit (OpCodes.Ldnull);
1026                                 ig.Emit (OpCodes.Cgt_Un);
1027                                 return;
1028                         }
1029                         throw new Exception ("never reached");
1030                 }
1031
1032                 public override Expression DoResolve (EmitContext ec)
1033                 {
1034                         Expression e = base.DoResolve (ec);
1035
1036                         if ((e == null) || (expr == null))
1037                                 return null;
1038
1039                         Type etype = expr.Type;
1040                         bool warning_always_matches = false;
1041                         bool warning_never_matches = false;
1042
1043                         type = TypeManager.bool_type;
1044                         eclass = ExprClass.Value;
1045
1046                         //
1047                         // First case, if at compile time, there is an implicit conversion
1048                         // then e != null (objects) or true (value types)
1049                         //
1050                         e = ConvertImplicitStandard (ec, expr, probe_type, loc);
1051                         if (e != null){
1052                                 expr = e;
1053                                 if (etype.IsValueType)
1054                                         action = Action.AlwaysTrue;
1055                                 else
1056                                         action = Action.LeaveOnStack;
1057
1058                                 warning_always_matches = true;
1059                         } else if (ExplicitReferenceConversionExists (etype, probe_type)){
1060                                 //
1061                                 // Second case: explicit reference convresion
1062                                 //
1063                                 if (expr is NullLiteral)
1064                                         action = Action.AlwaysFalse;
1065                                 else
1066                                         action = Action.Probe;
1067                         } else {
1068                                 action = Action.AlwaysFalse;
1069                                 warning_never_matches = true;
1070                         }
1071
1072                         if (RootContext.WarningLevel >= 1){
1073                                 if (warning_always_matches)
1074                                         Warning (
1075                                                 183,
1076                                                 "The expression is always of type `" +
1077                                                 TypeManager.CSharpName (probe_type) + "'");
1078                                 else if (warning_never_matches){
1079                                         if (!(probe_type.IsInterface || expr.Type.IsInterface))
1080                                                 Warning (
1081                                                         184,
1082                                                         "The expression is never of type `" +
1083                                                         TypeManager.CSharpName (probe_type) + "'");
1084                                 }
1085                         }
1086
1087                         return this;
1088                 }
1089         }
1090
1091         /// <summary>
1092         ///   Implementation of the `as' operator.
1093         /// </summary>
1094         public class As : Probe {
1095                 public As (Expression expr, Expression probe_type, Location l)
1096                         : base (expr, probe_type, l)
1097                 {
1098                 }
1099
1100                 bool do_isinst = false;
1101
1102                 public override void Emit (EmitContext ec)
1103                 {
1104                         ILGenerator ig = ec.ig;
1105
1106                         expr.Emit (ec);
1107
1108                         if (do_isinst)
1109                                 ig.Emit (OpCodes.Isinst, probe_type);
1110                 }
1111
1112                 static void Error_CannotConvertType (Type source, Type target, Location loc)
1113                 {
1114                         Report.Error (
1115                                 39, loc, "as operator can not convert from `" +
1116                                 TypeManager.CSharpName (source) + "' to `" +
1117                                 TypeManager.CSharpName (target) + "'");
1118                 }
1119
1120                 public override Expression DoResolve (EmitContext ec)
1121                 {
1122                         Expression e = base.DoResolve (ec);
1123
1124                         if (e == null)
1125                                 return null;
1126
1127                         type = probe_type;
1128                         eclass = ExprClass.Value;
1129                         Type etype = expr.Type;
1130
1131                         if (TypeManager.IsValueType (probe_type)){
1132                                 Report.Error (77, loc, "The as operator should be used with a reference type only (" +
1133                                               TypeManager.CSharpName (probe_type) + " is a value type");
1134                                 return null;
1135
1136                         }
1137
1138                         e = ConvertImplicit (ec, expr, probe_type, loc);
1139                         if (e != null){
1140                                 expr = e;
1141                                 do_isinst = false;
1142                                 return this;
1143                         }
1144
1145                         if (ExplicitReferenceConversionExists (etype, probe_type)){
1146                                 do_isinst = true;
1147                                 return this;
1148                         }
1149
1150                         Error_CannotConvertType (etype, probe_type, loc);
1151                         return null;
1152                 }
1153         }
1154
1155         /// <summary>
1156         ///   This represents a typecast in the source language.
1157         ///
1158         ///   FIXME: Cast expressions have an unusual set of parsing
1159         ///   rules, we need to figure those out.
1160         /// </summary>
1161         public class Cast : Expression {
1162                 Expression target_type;
1163                 Expression expr;
1164
1165                 public Cast (Expression cast_type, Expression expr, Location loc)
1166                 {
1167                         this.target_type = cast_type;
1168                         this.expr = expr;
1169                         this.loc = loc;
1170                 }
1171
1172                 public Expression TargetType {
1173                         get {
1174                                 return target_type;
1175                         }
1176                 }
1177
1178                 public Expression Expr {
1179                         get {
1180                                 return expr;
1181                         }
1182                         set {
1183                                 expr = value;
1184                         }
1185                 }
1186
1187                 /// <summary>
1188                 ///   Attempts to do a compile-time folding of a constant cast.
1189                 /// </summary>
1190                 Expression TryReduce (EmitContext ec, Type target_type)
1191                 {
1192                         if (expr is ByteConstant){
1193                                 byte v = ((ByteConstant) expr).Value;
1194
1195                                 if (target_type == TypeManager.sbyte_type)
1196                                         return new SByteConstant ((sbyte) v);
1197                                 if (target_type == TypeManager.short_type)
1198                                         return new ShortConstant ((short) v);
1199                                 if (target_type == TypeManager.ushort_type)
1200                                         return new UShortConstant ((ushort) v);
1201                                 if (target_type == TypeManager.int32_type)
1202                                         return new IntConstant ((int) v);
1203                                 if (target_type == TypeManager.uint32_type)
1204                                         return new UIntConstant ((uint) v);
1205                                 if (target_type == TypeManager.int64_type)
1206                                         return new LongConstant ((long) v);
1207                                 if (target_type == TypeManager.uint64_type)
1208                                         return new ULongConstant ((ulong) v);
1209                                 if (target_type == TypeManager.float_type)
1210                                         return new FloatConstant ((float) v);
1211                                 if (target_type == TypeManager.double_type)
1212                                         return new DoubleConstant ((double) v);
1213                                 if (target_type == TypeManager.char_type)
1214                                         return new CharConstant ((char) v);
1215                                 if (target_type == TypeManager.decimal_type)
1216                                         return new DecimalConstant ((decimal) v);
1217                         }
1218                         if (expr is SByteConstant){
1219                                 sbyte v = ((SByteConstant) expr).Value;
1220
1221                                 if (target_type == TypeManager.byte_type)
1222                                         return new ByteConstant ((byte) v);
1223                                 if (target_type == TypeManager.short_type)
1224                                         return new ShortConstant ((short) v);
1225                                 if (target_type == TypeManager.ushort_type)
1226                                         return new UShortConstant ((ushort) v);
1227                                 if (target_type == TypeManager.int32_type)
1228                                         return new IntConstant ((int) v);
1229                                 if (target_type == TypeManager.uint32_type)
1230                                         return new UIntConstant ((uint) v);
1231                                 if (target_type == TypeManager.int64_type)
1232                                         return new LongConstant ((long) v);
1233                                 if (target_type == TypeManager.uint64_type)
1234                                         return new ULongConstant ((ulong) v);
1235                                 if (target_type == TypeManager.float_type)
1236                                         return new FloatConstant ((float) v);
1237                                 if (target_type == TypeManager.double_type)
1238                                         return new DoubleConstant ((double) v);
1239                                 if (target_type == TypeManager.char_type)
1240                                         return new CharConstant ((char) v);
1241                                 if (target_type == TypeManager.decimal_type)
1242                                         return new DecimalConstant ((decimal) v);
1243                         }
1244                         if (expr is ShortConstant){
1245                                 short v = ((ShortConstant) expr).Value;
1246
1247                                 if (target_type == TypeManager.byte_type)
1248                                         return new ByteConstant ((byte) v);
1249                                 if (target_type == TypeManager.sbyte_type)
1250                                         return new SByteConstant ((sbyte) v);
1251                                 if (target_type == TypeManager.ushort_type)
1252                                         return new UShortConstant ((ushort) v);
1253                                 if (target_type == TypeManager.int32_type)
1254                                         return new IntConstant ((int) v);
1255                                 if (target_type == TypeManager.uint32_type)
1256                                         return new UIntConstant ((uint) v);
1257                                 if (target_type == TypeManager.int64_type)
1258                                         return new LongConstant ((long) v);
1259                                 if (target_type == TypeManager.uint64_type)
1260                                         return new ULongConstant ((ulong) v);
1261                                 if (target_type == TypeManager.float_type)
1262                                         return new FloatConstant ((float) v);
1263                                 if (target_type == TypeManager.double_type)
1264                                         return new DoubleConstant ((double) v);
1265                                 if (target_type == TypeManager.char_type)
1266                                         return new CharConstant ((char) v);
1267                                 if (target_type == TypeManager.decimal_type)
1268                                         return new DecimalConstant ((decimal) v);
1269                         }
1270                         if (expr is UShortConstant){
1271                                 ushort v = ((UShortConstant) expr).Value;
1272
1273                                 if (target_type == TypeManager.byte_type)
1274                                         return new ByteConstant ((byte) v);
1275                                 if (target_type == TypeManager.sbyte_type)
1276                                         return new SByteConstant ((sbyte) v);
1277                                 if (target_type == TypeManager.short_type)
1278                                         return new ShortConstant ((short) v);
1279                                 if (target_type == TypeManager.int32_type)
1280                                         return new IntConstant ((int) v);
1281                                 if (target_type == TypeManager.uint32_type)
1282                                         return new UIntConstant ((uint) v);
1283                                 if (target_type == TypeManager.int64_type)
1284                                         return new LongConstant ((long) v);
1285                                 if (target_type == TypeManager.uint64_type)
1286                                         return new ULongConstant ((ulong) v);
1287                                 if (target_type == TypeManager.float_type)
1288                                         return new FloatConstant ((float) v);
1289                                 if (target_type == TypeManager.double_type)
1290                                         return new DoubleConstant ((double) v);
1291                                 if (target_type == TypeManager.char_type)
1292                                         return new CharConstant ((char) v);
1293                                 if (target_type == TypeManager.decimal_type)
1294                                         return new DecimalConstant ((decimal) v);
1295                         }
1296                         if (expr is IntConstant){
1297                                 int v = ((IntConstant) expr).Value;
1298
1299                                 if (target_type == TypeManager.byte_type)
1300                                         return new ByteConstant ((byte) v);
1301                                 if (target_type == TypeManager.sbyte_type)
1302                                         return new SByteConstant ((sbyte) v);
1303                                 if (target_type == TypeManager.short_type)
1304                                         return new ShortConstant ((short) v);
1305                                 if (target_type == TypeManager.ushort_type)
1306                                         return new UShortConstant ((ushort) v);
1307                                 if (target_type == TypeManager.uint32_type)
1308                                         return new UIntConstant ((uint) v);
1309                                 if (target_type == TypeManager.int64_type)
1310                                         return new LongConstant ((long) v);
1311                                 if (target_type == TypeManager.uint64_type)
1312                                         return new ULongConstant ((ulong) v);
1313                                 if (target_type == TypeManager.float_type)
1314                                         return new FloatConstant ((float) v);
1315                                 if (target_type == TypeManager.double_type)
1316                                         return new DoubleConstant ((double) v);
1317                                 if (target_type == TypeManager.char_type)
1318                                         return new CharConstant ((char) v);
1319                                 if (target_type == TypeManager.decimal_type)
1320                                         return new DecimalConstant ((decimal) v);
1321                         }
1322                         if (expr is UIntConstant){
1323                                 uint v = ((UIntConstant) expr).Value;
1324
1325                                 if (target_type == TypeManager.byte_type)
1326                                         return new ByteConstant ((byte) v);
1327                                 if (target_type == TypeManager.sbyte_type)
1328                                         return new SByteConstant ((sbyte) v);
1329                                 if (target_type == TypeManager.short_type)
1330                                         return new ShortConstant ((short) v);
1331                                 if (target_type == TypeManager.ushort_type)
1332                                         return new UShortConstant ((ushort) v);
1333                                 if (target_type == TypeManager.int32_type)
1334                                         return new IntConstant ((int) v);
1335                                 if (target_type == TypeManager.int64_type)
1336                                         return new LongConstant ((long) v);
1337                                 if (target_type == TypeManager.uint64_type)
1338                                         return new ULongConstant ((ulong) v);
1339                                 if (target_type == TypeManager.float_type)
1340                                         return new FloatConstant ((float) v);
1341                                 if (target_type == TypeManager.double_type)
1342                                         return new DoubleConstant ((double) v);
1343                                 if (target_type == TypeManager.char_type)
1344                                         return new CharConstant ((char) v);
1345                                 if (target_type == TypeManager.decimal_type)
1346                                         return new DecimalConstant ((decimal) v);
1347                         }
1348                         if (expr is LongConstant){
1349                                 long v = ((LongConstant) expr).Value;
1350
1351                                 if (target_type == TypeManager.byte_type)
1352                                         return new ByteConstant ((byte) v);
1353                                 if (target_type == TypeManager.sbyte_type)
1354                                         return new SByteConstant ((sbyte) v);
1355                                 if (target_type == TypeManager.short_type)
1356                                         return new ShortConstant ((short) v);
1357                                 if (target_type == TypeManager.ushort_type)
1358                                         return new UShortConstant ((ushort) v);
1359                                 if (target_type == TypeManager.int32_type)
1360                                         return new IntConstant ((int) v);
1361                                 if (target_type == TypeManager.uint32_type)
1362                                         return new UIntConstant ((uint) v);
1363                                 if (target_type == TypeManager.uint64_type)
1364                                         return new ULongConstant ((ulong) v);
1365                                 if (target_type == TypeManager.float_type)
1366                                         return new FloatConstant ((float) v);
1367                                 if (target_type == TypeManager.double_type)
1368                                         return new DoubleConstant ((double) v);
1369                                 if (target_type == TypeManager.char_type)
1370                                         return new CharConstant ((char) v);
1371                                 if (target_type == TypeManager.decimal_type)
1372                                         return new DecimalConstant ((decimal) v);
1373                         }
1374                         if (expr is ULongConstant){
1375                                 ulong v = ((ULongConstant) expr).Value;
1376
1377                                 if (target_type == TypeManager.byte_type)
1378                                         return new ByteConstant ((byte) v);
1379                                 if (target_type == TypeManager.sbyte_type)
1380                                         return new SByteConstant ((sbyte) v);
1381                                 if (target_type == TypeManager.short_type)
1382                                         return new ShortConstant ((short) v);
1383                                 if (target_type == TypeManager.ushort_type)
1384                                         return new UShortConstant ((ushort) v);
1385                                 if (target_type == TypeManager.int32_type)
1386                                         return new IntConstant ((int) v);
1387                                 if (target_type == TypeManager.uint32_type)
1388                                         return new UIntConstant ((uint) v);
1389                                 if (target_type == TypeManager.int64_type)
1390                                         return new LongConstant ((long) v);
1391                                 if (target_type == TypeManager.float_type)
1392                                         return new FloatConstant ((float) v);
1393                                 if (target_type == TypeManager.double_type)
1394                                         return new DoubleConstant ((double) v);
1395                                 if (target_type == TypeManager.char_type)
1396                                         return new CharConstant ((char) v);
1397                                 if (target_type == TypeManager.decimal_type)
1398                                         return new DecimalConstant ((decimal) v);
1399                         }
1400                         if (expr is FloatConstant){
1401                                 float v = ((FloatConstant) expr).Value;
1402
1403                                 if (target_type == TypeManager.byte_type)
1404                                         return new ByteConstant ((byte) v);
1405                                 if (target_type == TypeManager.sbyte_type)
1406                                         return new SByteConstant ((sbyte) v);
1407                                 if (target_type == TypeManager.short_type)
1408                                         return new ShortConstant ((short) v);
1409                                 if (target_type == TypeManager.ushort_type)
1410                                         return new UShortConstant ((ushort) v);
1411                                 if (target_type == TypeManager.int32_type)
1412                                         return new IntConstant ((int) v);
1413                                 if (target_type == TypeManager.uint32_type)
1414                                         return new UIntConstant ((uint) v);
1415                                 if (target_type == TypeManager.int64_type)
1416                                         return new LongConstant ((long) v);
1417                                 if (target_type == TypeManager.uint64_type)
1418                                         return new ULongConstant ((ulong) v);
1419                                 if (target_type == TypeManager.double_type)
1420                                         return new DoubleConstant ((double) v);
1421                                 if (target_type == TypeManager.char_type)
1422                                         return new CharConstant ((char) v);
1423                                 if (target_type == TypeManager.decimal_type)
1424                                         return new DecimalConstant ((decimal) v);
1425                         }
1426                         if (expr is DoubleConstant){
1427                                 double v = ((DoubleConstant) expr).Value;
1428
1429                                 if (target_type == TypeManager.byte_type)
1430                                         return new ByteConstant ((byte) v);
1431                                 if (target_type == TypeManager.sbyte_type)
1432                                         return new SByteConstant ((sbyte) v);
1433                                 if (target_type == TypeManager.short_type)
1434                                         return new ShortConstant ((short) v);
1435                                 if (target_type == TypeManager.ushort_type)
1436                                         return new UShortConstant ((ushort) v);
1437                                 if (target_type == TypeManager.int32_type)
1438                                         return new IntConstant ((int) v);
1439                                 if (target_type == TypeManager.uint32_type)
1440                                         return new UIntConstant ((uint) v);
1441                                 if (target_type == TypeManager.int64_type)
1442                                         return new LongConstant ((long) v);
1443                                 if (target_type == TypeManager.uint64_type)
1444                                         return new ULongConstant ((ulong) v);
1445                                 if (target_type == TypeManager.float_type)
1446                                         return new FloatConstant ((float) v);
1447                                 if (target_type == TypeManager.char_type)
1448                                         return new CharConstant ((char) v);
1449                                 if (target_type == TypeManager.decimal_type)
1450                                         return new DecimalConstant ((decimal) v);
1451                         }
1452
1453                         return null;
1454                 }
1455
1456                 public override Expression DoResolve (EmitContext ec)
1457                 {
1458                         expr = expr.Resolve (ec);
1459                         if (expr == null)
1460                                 return null;
1461
1462                         int errors = Report.Errors;
1463
1464                         type = ec.DeclSpace.ResolveType (target_type, false, Location);
1465
1466                         if (type == null)
1467                                 return null;
1468
1469                         eclass = ExprClass.Value;
1470
1471                         if (expr is Constant){
1472                                 Expression e = TryReduce (ec, type);
1473
1474                                 if (e != null)
1475                                         return e;
1476                         }
1477
1478                         expr = ConvertExplicit (ec, expr, type, loc);
1479                         return expr;
1480                 }
1481
1482                 public override void Emit (EmitContext ec)
1483                 {
1484                         //
1485                         // This one will never happen
1486                         //
1487                         throw new Exception ("Should not happen");
1488                 }
1489         }
1490
1491         /// <summary>
1492         ///   Binary operators
1493         /// </summary>
1494         public class Binary : Expression {
1495                 public enum Operator : byte {
1496                         Multiply, Division, Modulus,
1497                         Addition, Subtraction,
1498                         LeftShift, RightShift,
1499                         LessThan, GreaterThan, LessThanOrEqual, GreaterThanOrEqual,
1500                         Equality, Inequality,
1501                         BitwiseAnd,
1502                         ExclusiveOr,
1503                         BitwiseOr,
1504                         LogicalAnd,
1505                         LogicalOr,
1506                         TOP
1507                 }
1508
1509                 Operator oper;
1510                 Expression left, right;
1511
1512                 //
1513                 // After resolution, method might contain the operator overload
1514                 // method.
1515                 //
1516                 protected MethodBase method;
1517                 ArrayList  Arguments;
1518
1519                 bool DelegateOperation;
1520
1521                 // This must be kept in sync with Operator!!!
1522                 static string [] oper_names;
1523
1524                 static Binary ()
1525                 {
1526                         oper_names = new string [(int) Operator.TOP];
1527
1528                         oper_names [(int) Operator.Multiply] = "op_Multiply";
1529                         oper_names [(int) Operator.Division] = "op_Division";
1530                         oper_names [(int) Operator.Modulus] = "op_Modulus";
1531                         oper_names [(int) Operator.Addition] = "op_Addition";
1532                         oper_names [(int) Operator.Subtraction] = "op_Subtraction";
1533                         oper_names [(int) Operator.LeftShift] = "op_LeftShift";
1534                         oper_names [(int) Operator.RightShift] = "op_RightShift";
1535                         oper_names [(int) Operator.LessThan] = "op_LessThan";
1536                         oper_names [(int) Operator.GreaterThan] = "op_GreaterThan";
1537                         oper_names [(int) Operator.LessThanOrEqual] = "op_LessThanOrEqual";
1538                         oper_names [(int) Operator.GreaterThanOrEqual] = "op_GreaterThanOrEqual";
1539                         oper_names [(int) Operator.Equality] = "op_Equality";
1540                         oper_names [(int) Operator.Inequality] = "op_Inequality";
1541                         oper_names [(int) Operator.BitwiseAnd] = "op_BitwiseAnd";
1542                         oper_names [(int) Operator.BitwiseOr] = "op_BitwiseOr";
1543                         oper_names [(int) Operator.ExclusiveOr] = "op_ExclusiveOr";
1544                         oper_names [(int) Operator.LogicalOr] = "op_LogicalOr";
1545                         oper_names [(int) Operator.LogicalAnd] = "op_LogicalAnd";
1546                 }
1547
1548                 public Binary (Operator oper, Expression left, Expression right, Location loc)
1549                 {
1550                         this.oper = oper;
1551                         this.left = left;
1552                         this.right = right;
1553                         this.loc = loc;
1554                 }
1555
1556                 public Operator Oper {
1557                         get {
1558                                 return oper;
1559                         }
1560                         set {
1561                                 oper = value;
1562                         }
1563                 }
1564
1565                 public Expression Left {
1566                         get {
1567                                 return left;
1568                         }
1569                         set {
1570                                 left = value;
1571                         }
1572                 }
1573
1574                 public Expression Right {
1575                         get {
1576                                 return right;
1577                         }
1578                         set {
1579                                 right = value;
1580                         }
1581                 }
1582
1583
1584                 /// <summary>
1585                 ///   Returns a stringified representation of the Operator
1586                 /// </summary>
1587                 static string OperName (Operator oper)
1588                 {
1589                         switch (oper){
1590                         case Operator.Multiply:
1591                                 return "*";
1592                         case Operator.Division:
1593                                 return "/";
1594                         case Operator.Modulus:
1595                                 return "%";
1596                         case Operator.Addition:
1597                                 return "+";
1598                         case Operator.Subtraction:
1599                                 return "-";
1600                         case Operator.LeftShift:
1601                                 return "<<";
1602                         case Operator.RightShift:
1603                                 return ">>";
1604                         case Operator.LessThan:
1605                                 return "<";
1606                         case Operator.GreaterThan:
1607                                 return ">";
1608                         case Operator.LessThanOrEqual:
1609                                 return "<=";
1610                         case Operator.GreaterThanOrEqual:
1611                                 return ">=";
1612                         case Operator.Equality:
1613                                 return "==";
1614                         case Operator.Inequality:
1615                                 return "!=";
1616                         case Operator.BitwiseAnd:
1617                                 return "&";
1618                         case Operator.BitwiseOr:
1619                                 return "|";
1620                         case Operator.ExclusiveOr:
1621                                 return "^";
1622                         case Operator.LogicalOr:
1623                                 return "||";
1624                         case Operator.LogicalAnd:
1625                                 return "&&";
1626                         }
1627
1628                         return oper.ToString ();
1629                 }
1630
1631                 public override string ToString ()
1632                 {
1633                         return "operator " + OperName (oper) + "(" + left.ToString () + ", " +
1634                                 right.ToString () + ")";
1635                 }
1636
1637                 Expression ForceConversion (EmitContext ec, Expression expr, Type target_type)
1638                 {
1639                         if (expr.Type == target_type)
1640                                 return expr;
1641
1642                         return ConvertImplicit (ec, expr, target_type, new Location (-1));
1643                 }
1644
1645                 public static void Error_OperatorAmbiguous (Location loc, Operator oper, Type l, Type r)
1646                 {
1647                         Report.Error (
1648                                 34, loc, "Operator `" + OperName (oper)
1649                                 + "' is ambiguous on operands of type `"
1650                                 + TypeManager.CSharpName (l) + "' "
1651                                 + "and `" + TypeManager.CSharpName (r)
1652                                 + "'");
1653                 }
1654
1655                 //
1656                 // Note that handling the case l == Decimal || r == Decimal
1657                 // is taken care of by the Step 1 Operator Overload resolution.
1658                 //
1659                 bool DoNumericPromotions (EmitContext ec, Type l, Type r)
1660                 {
1661                         if (l == TypeManager.double_type || r == TypeManager.double_type){
1662                                 //
1663                                 // If either operand is of type double, the other operand is
1664                                 // conveted to type double.
1665                                 //
1666                                 if (r != TypeManager.double_type)
1667                                         right = ConvertImplicit (ec, right, TypeManager.double_type, loc);
1668                                 if (l != TypeManager.double_type)
1669                                         left = ConvertImplicit (ec, left, TypeManager.double_type, loc);
1670
1671                                 type = TypeManager.double_type;
1672                         } else if (l == TypeManager.float_type || r == TypeManager.float_type){
1673                                 //
1674                                 // if either operand is of type float, the other operand is
1675                                 // converted to type float.
1676                                 //
1677                                 if (r != TypeManager.double_type)
1678                                         right = ConvertImplicit (ec, right, TypeManager.float_type, loc);
1679                                 if (l != TypeManager.double_type)
1680                                         left = ConvertImplicit (ec, left, TypeManager.float_type, loc);
1681                                 type = TypeManager.float_type;
1682                         } else if (l == TypeManager.uint64_type || r == TypeManager.uint64_type){
1683                                 Expression e;
1684                                 Type other;
1685                                 //
1686                                 // If either operand is of type ulong, the other operand is
1687                                 // converted to type ulong.  or an error ocurrs if the other
1688                                 // operand is of type sbyte, short, int or long
1689                                 //
1690                                 if (l == TypeManager.uint64_type){
1691                                         if (r != TypeManager.uint64_type){
1692                                                 if (right is IntConstant){
1693                                                         IntConstant ic = (IntConstant) right;
1694
1695                                                         e = TryImplicitIntConversion (l, ic);
1696                                                         if (e != null)
1697                                                                 right = e;
1698                                                 } else if (right is LongConstant){
1699                                                         long ll = ((LongConstant) right).Value;
1700
1701                                                         if (ll > 0)
1702                                                                 right = new ULongConstant ((ulong) ll);
1703                                                 } else {
1704                                                         e = ImplicitNumericConversion (ec, right, l, loc);
1705                                                         if (e != null)
1706                                                                 right = e;
1707                                                 }
1708                                         }
1709                                         other = right.Type;
1710                                 } else {
1711                                         if (left is IntConstant){
1712                                                 e = TryImplicitIntConversion (r, (IntConstant) left);
1713                                                 if (e != null)
1714                                                         left = e;
1715                                         } else if (left is LongConstant){
1716                                                 long ll = ((LongConstant) left).Value;
1717
1718                                                 if (ll > 0)
1719                                                         left = new ULongConstant ((ulong) ll);
1720                                         } else {
1721                                                 e = ImplicitNumericConversion (ec, left, r, loc);
1722                                                 if (e != null)
1723                                                         left = e;
1724                                         }
1725                                         other = left.Type;
1726                                 }
1727
1728                                 if ((other == TypeManager.sbyte_type) ||
1729                                     (other == TypeManager.short_type) ||
1730                                     (other == TypeManager.int32_type) ||
1731                                     (other == TypeManager.int64_type))
1732                                         Error_OperatorAmbiguous (loc, oper, l, r);
1733                                 type = TypeManager.uint64_type;
1734                         } else if (l == TypeManager.int64_type || r == TypeManager.int64_type){
1735                                 //
1736                                 // If either operand is of type long, the other operand is converted
1737                                 // to type long.
1738                                 //
1739                                 if (l != TypeManager.int64_type)
1740                                         left = ConvertImplicit (ec, left, TypeManager.int64_type, loc);
1741                                 if (r != TypeManager.int64_type)
1742                                         right = ConvertImplicit (ec, right, TypeManager.int64_type, loc);
1743
1744                                 type = TypeManager.int64_type;
1745                         } else if (l == TypeManager.uint32_type || r == TypeManager.uint32_type){
1746                                 //
1747                                 // If either operand is of type uint, and the other
1748                                 // operand is of type sbyte, short or int, othe operands are
1749                                 // converted to type long.
1750                                 //
1751                                 Type other = null;
1752
1753                                 if (l == TypeManager.uint32_type){
1754                                         if (right is IntConstant){
1755                                                 IntConstant ic = (IntConstant) right;
1756                                                 int val = ic.Value;
1757
1758                                                 if (val >= 0)
1759                                                         right = new UIntConstant ((uint) val);
1760
1761                                                 type = l;
1762                                                 return true;
1763                                         }
1764                                         other = r;
1765                                 }
1766                                 else if (r == TypeManager.uint32_type){
1767                                         if (left is IntConstant){
1768                                                 IntConstant ic = (IntConstant) left;
1769                                                 int val = ic.Value;
1770
1771                                                 if (val >= 0)
1772                                                         left = new UIntConstant ((uint) val);
1773
1774                                                 type = r;
1775                                                 return true;
1776                                         }
1777
1778                                         other = l;
1779                                 }
1780
1781                                 if ((other == TypeManager.sbyte_type) ||
1782                                     (other == TypeManager.short_type) ||
1783                                     (other == TypeManager.int32_type)){
1784                                         left = ForceConversion (ec, left, TypeManager.int64_type);
1785                                         right = ForceConversion (ec, right, TypeManager.int64_type);
1786                                         type = TypeManager.int64_type;
1787                                 } else {
1788                                         //
1789                                         // if either operand is of type uint, the other
1790                                         // operand is converd to type uint
1791                                         //
1792                                         left = ForceConversion (ec, left, TypeManager.uint32_type);
1793                                         right = ForceConversion (ec, right, TypeManager.uint32_type);
1794                                         type = TypeManager.uint32_type;
1795                                 }
1796                         } else if (l == TypeManager.decimal_type || r == TypeManager.decimal_type){
1797                                 if (l != TypeManager.decimal_type)
1798                                         left = ConvertImplicit (ec, left, TypeManager.decimal_type, loc);
1799
1800                                 if (r != TypeManager.decimal_type)
1801                                         right = ConvertImplicit (ec, right, TypeManager.decimal_type, loc);
1802                                 type = TypeManager.decimal_type;
1803                         } else {
1804                                 left = ForceConversion (ec, left, TypeManager.int32_type);
1805                                 right = ForceConversion (ec, right, TypeManager.int32_type);
1806
1807                                 type = TypeManager.int32_type;
1808                         }
1809
1810                         return (left != null) && (right != null);
1811                 }
1812
1813                 static public void Error_OperatorCannotBeApplied (Location loc, string name, Type l, Type r)
1814                 {
1815                         Report.Error (19, loc,
1816                                "Operator " + name + " cannot be applied to operands of type `" +
1817                                TypeManager.CSharpName (l) + "' and `" +
1818                                TypeManager.CSharpName (r) + "'");
1819                 }
1820
1821                 void Error_OperatorCannotBeApplied ()
1822                 {
1823                         Error_OperatorCannotBeApplied (loc, OperName (oper), left.Type, right.Type);
1824                 }
1825
1826                 static bool is_32_or_64 (Type t)
1827                 {
1828                         return (t == TypeManager.int32_type || t == TypeManager.uint32_type ||
1829                                 t == TypeManager.int64_type || t == TypeManager.uint64_type);
1830                 }
1831
1832                 static bool is_unsigned (Type t)
1833                 {
1834                         return (t == TypeManager.uint32_type || t == TypeManager.uint64_type ||
1835                                 t == TypeManager.short_type || t == TypeManager.byte_type);
1836                 }
1837
1838                 Expression CheckShiftArguments (EmitContext ec)
1839                 {
1840                         Expression e;
1841                         Type l = left.Type;
1842                         Type r = right.Type;
1843
1844                         e = ForceConversion (ec, right, TypeManager.int32_type);
1845                         if (e == null){
1846                                 Error_OperatorCannotBeApplied ();
1847                                 return null;
1848                         }
1849                         right = e;
1850
1851                         if (((e = ConvertImplicit (ec, left, TypeManager.int32_type, loc)) != null) ||
1852                             ((e = ConvertImplicit (ec, left, TypeManager.uint32_type, loc)) != null) ||
1853                             ((e = ConvertImplicit (ec, left, TypeManager.int64_type, loc)) != null) ||
1854                             ((e = ConvertImplicit (ec, left, TypeManager.uint64_type, loc)) != null)){
1855                                 left = e;
1856                                 type = e.Type;
1857
1858                                 return this;
1859                         }
1860                         Error_OperatorCannotBeApplied ();
1861                         return null;
1862                 }
1863
1864                 Expression ResolveOperator (EmitContext ec)
1865                 {
1866                         Type l = left.Type;
1867                         Type r = right.Type;
1868
1869                         bool overload_failed = false;
1870
1871                         //
1872                         // Step 1: Perform Operator Overload location
1873                         //
1874                         Expression left_expr, right_expr;
1875
1876                         string op = oper_names [(int) oper];
1877
1878                         MethodGroupExpr union;
1879                         left_expr = MemberLookup (ec, l, op, MemberTypes.Method, AllBindingFlags, loc);
1880                         if (r != l){
1881                                 right_expr = MemberLookup (
1882                                         ec, r, op, MemberTypes.Method, AllBindingFlags, loc);
1883                                 union = Invocation.MakeUnionSet (left_expr, right_expr, loc);
1884                         } else
1885                                 union = (MethodGroupExpr) left_expr;
1886
1887                         if (union != null) {
1888                                 Arguments = new ArrayList ();
1889                                 Arguments.Add (new Argument (left, Argument.AType.Expression));
1890                                 Arguments.Add (new Argument (right, Argument.AType.Expression));
1891
1892                                 method = Invocation.OverloadResolve (ec, union, Arguments, Location.Null);
1893                                 if (method != null) {
1894                                         MethodInfo mi = (MethodInfo) method;
1895
1896                                         type = mi.ReturnType;
1897                                         return this;
1898                                 } else {
1899                                         overload_failed = true;
1900                                 }
1901                         }
1902
1903                         //
1904                         // Step 2: Default operations on CLI native types.
1905                         //
1906
1907                         //
1908                         // Step 0: String concatenation (because overloading will get this wrong)
1909                         //
1910                         if (oper == Operator.Addition){
1911                                 //
1912                                 // If any of the arguments is a string, cast to string
1913                                 //
1914
1915                                 if (l == TypeManager.string_type){
1916
1917                                         if (r == TypeManager.void_type) {
1918                                                 Error_OperatorCannotBeApplied ();
1919                                                 return null;
1920                                         }
1921
1922                                         if (r == TypeManager.string_type){
1923                                                 if (left is Constant && right is Constant){
1924                                                         StringConstant ls = (StringConstant) left;
1925                                                         StringConstant rs = (StringConstant) right;
1926
1927                                                         return new StringConstant (
1928                                                                 ls.Value + rs.Value);
1929                                                 }
1930
1931                                                 // string + string
1932                                                 method = TypeManager.string_concat_string_string;
1933                                         } else {
1934                                                 // string + object
1935                                                 method = TypeManager.string_concat_object_object;
1936                                                 right = ConvertImplicit (ec, right,
1937                                                                          TypeManager.object_type, loc);
1938                                                 if (right == null){
1939                                                         Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
1940                                                         return null;
1941                                                 }
1942                                         }
1943                                         type = TypeManager.string_type;
1944
1945                                         Arguments = new ArrayList ();
1946                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
1947                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
1948
1949                                         return this;
1950
1951                                 } else if (r == TypeManager.string_type){
1952                                         // object + string
1953
1954                                         if (l == TypeManager.void_type) {
1955                                                 Error_OperatorCannotBeApplied ();
1956                                                 return null;
1957                                         }
1958
1959                                         method = TypeManager.string_concat_object_object;
1960                                         left = ConvertImplicit (ec, left, TypeManager.object_type, loc);
1961                                         if (left == null){
1962                                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
1963                                                 return null;
1964                                         }
1965                                         Arguments = new ArrayList ();
1966                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
1967                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
1968
1969                                         type = TypeManager.string_type;
1970
1971                                         return this;
1972                                 }
1973
1974                                 //
1975                                 // Transform a + ( - b) into a - b
1976                                 //
1977                                 if (right is Unary){
1978                                         Unary right_unary = (Unary) right;
1979
1980                                         if (right_unary.Oper == Unary.Operator.UnaryNegation){
1981                                                 oper = Operator.Subtraction;
1982                                                 right = right_unary.Expr;
1983                                                 r = right.Type;
1984                                         }
1985                                 }
1986                         }
1987
1988                         if (oper == Operator.Equality || oper == Operator.Inequality){
1989                                 if (l == TypeManager.bool_type || r == TypeManager.bool_type){
1990                                         if (r != TypeManager.bool_type || l != TypeManager.bool_type){
1991                                                 Error_OperatorCannotBeApplied ();
1992                                                 return null;
1993                                         }
1994
1995                                         type = TypeManager.bool_type;
1996                                         return this;
1997                                 }
1998
1999                                 //
2000                                 // operator != (object a, object b)
2001                                 // operator == (object a, object b)
2002                                 //
2003                                 // For this to be used, both arguments have to be reference-types.
2004                                 // Read the rationale on the spec (14.9.6)
2005                                 //
2006                                 // Also, if at compile time we know that the classes do not inherit
2007                                 // one from the other, then we catch the error there.
2008                                 //
2009                                 if (!(l.IsValueType || r.IsValueType)){
2010                                         type = TypeManager.bool_type;
2011
2012                                         if (l == r)
2013                                                 return this;
2014
2015                                         if (l.IsSubclassOf (r) || r.IsSubclassOf (l))
2016                                                 return this;
2017
2018                                         //
2019                                         // Also, a standard conversion must exist from either one
2020                                         //
2021                                         if (!(StandardConversionExists (left, r) ||
2022                                               StandardConversionExists (right, l))){
2023                                                 Error_OperatorCannotBeApplied ();
2024                                                 return null;
2025                                         }
2026                                         //
2027                                         // We are going to have to convert to an object to compare
2028                                         //
2029                                         if (l != TypeManager.object_type)
2030                                                 left = new EmptyCast (left, TypeManager.object_type);
2031                                         if (r != TypeManager.object_type)
2032                                                 right = new EmptyCast (right, TypeManager.object_type);
2033
2034                                         //
2035                                         // FIXME: CSC here catches errors cs254 and cs252
2036                                         //
2037                                         return this;
2038                                 }
2039
2040                                 //
2041                                 // One of them is a valuetype, but the other one is not.
2042                                 //
2043                                 if (!l.IsValueType || !r.IsValueType) {
2044                                         Error_OperatorCannotBeApplied ();
2045                                         return null;
2046                                 }
2047                         }
2048
2049                         // Only perform numeric promotions on:
2050                         // +, -, *, /, %, &, |, ^, ==, !=, <, >, <=, >=
2051                         //
2052                         if (oper == Operator.Addition || oper == Operator.Subtraction) {
2053                                 if (l.IsSubclassOf (TypeManager.delegate_type) &&
2054                                     r.IsSubclassOf (TypeManager.delegate_type)) {
2055
2056                                         Arguments = new ArrayList ();
2057                                         Arguments.Add (new Argument (left, Argument.AType.Expression));
2058                                         Arguments.Add (new Argument (right, Argument.AType.Expression));
2059
2060                                         if (oper == Operator.Addition)
2061                                                 method = TypeManager.delegate_combine_delegate_delegate;
2062                                         else
2063                                                 method = TypeManager.delegate_remove_delegate_delegate;
2064
2065                                         if (l != r) {
2066                                                 Error_OperatorCannotBeApplied ();
2067                                                 return null;
2068                                         }
2069
2070                                         DelegateOperation = true;
2071                                         type = l;
2072                                         return this;
2073                                 }
2074
2075                                 //
2076                                 // Pointer arithmetic:
2077                                 //
2078                                 // T* operator + (T* x, int y);
2079                                 // T* operator + (T* x, uint y);
2080                                 // T* operator + (T* x, long y);
2081                                 // T* operator + (T* x, ulong y);
2082                                 //
2083                                 // T* operator + (int y,   T* x);
2084                                 // T* operator + (uint y,  T *x);
2085                                 // T* operator + (long y,  T *x);
2086                                 // T* operator + (ulong y, T *x);
2087                                 //
2088                                 // T* operator - (T* x, int y);
2089                                 // T* operator - (T* x, uint y);
2090                                 // T* operator - (T* x, long y);
2091                                 // T* operator - (T* x, ulong y);
2092                                 //
2093                                 // long operator - (T* x, T *y)
2094                                 //
2095                                 if (l.IsPointer){
2096                                         if (r.IsPointer && oper == Operator.Subtraction){
2097                                                 if (r == l)
2098                                                         return new PointerArithmetic (
2099                                                                 false, left, right, TypeManager.int64_type,
2100                                                                 loc);
2101                                         } else if (is_32_or_64 (r))
2102                                                 return new PointerArithmetic (
2103                                                         oper == Operator.Addition, left, right, l, loc);
2104                                 } else if (r.IsPointer && is_32_or_64 (l) && oper == Operator.Addition)
2105                                         return new PointerArithmetic (
2106                                                 true, right, left, r, loc);
2107                         }
2108
2109                         //
2110                         // Enumeration operators
2111                         //
2112                         bool lie = TypeManager.IsEnumType (l);
2113                         bool rie = TypeManager.IsEnumType (r);
2114                         if (lie || rie){
2115                                 Expression temp;
2116
2117                                 // U operator - (E e, E f)
2118                                 if (lie && rie && oper == Operator.Subtraction){
2119                                         if (l == r){
2120                                                 type = TypeManager.EnumToUnderlying (l);
2121                                                 return this;
2122                                         }
2123                                         Error_OperatorCannotBeApplied ();
2124                                         return null;
2125                                 }
2126
2127                                 //
2128                                 // operator + (E e, U x)
2129                                 // operator - (E e, U x)
2130                                 //
2131                                 if (oper == Operator.Addition || oper == Operator.Subtraction){
2132                                         Type enum_type = lie ? l : r;
2133                                         Type other_type = lie ? r : l;
2134                                         Type underlying_type = TypeManager.EnumToUnderlying (enum_type);
2135 ;
2136
2137                                         if (underlying_type != other_type){
2138                                                 Error_OperatorCannotBeApplied ();
2139                                                 return null;
2140                                         }
2141
2142                                         type = enum_type;
2143                                         return this;
2144                                 }
2145
2146                                 if (!rie){
2147                                         temp = ConvertImplicit (ec, right, l, loc);
2148                                         if (temp != null)
2149                                                 right = temp;
2150                                         else {
2151                                                 Error_OperatorCannotBeApplied ();
2152                                                 return null;
2153                                         }
2154                                 } if (!lie){
2155                                         temp = ConvertImplicit (ec, left, r, loc);
2156                                         if (temp != null){
2157                                                 left = temp;
2158                                                 l = r;
2159                                         } else {
2160                                                 Error_OperatorCannotBeApplied ();
2161                                                 return null;
2162                                         }
2163                                 }
2164
2165                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2166                                     oper == Operator.LessThanOrEqual || oper == Operator.LessThan ||
2167                                     oper == Operator.GreaterThanOrEqual || oper == Operator.GreaterThan){
2168                                         type = TypeManager.bool_type;
2169                                         return this;
2170                                 }
2171
2172                                 if (oper == Operator.BitwiseAnd ||
2173                                     oper == Operator.BitwiseOr ||
2174                                     oper == Operator.ExclusiveOr){
2175                                         type = l;
2176                                         return this;
2177                                 }
2178                                 Error_OperatorCannotBeApplied ();
2179                                 return null;
2180                         }
2181
2182                         if (oper == Operator.LeftShift || oper == Operator.RightShift)
2183                                 return CheckShiftArguments (ec);
2184
2185                         if (oper == Operator.LogicalOr || oper == Operator.LogicalAnd){
2186                                 if (l != TypeManager.bool_type || r != TypeManager.bool_type){
2187                                         Error_OperatorCannotBeApplied ();
2188                                         return null;
2189                                 }
2190
2191                                 type = TypeManager.bool_type;
2192                                 return this;
2193                         }
2194
2195                         //
2196                         // operator & (bool x, bool y)
2197                         // operator | (bool x, bool y)
2198                         // operator ^ (bool x, bool y)
2199                         //
2200                         if (l == TypeManager.bool_type && r == TypeManager.bool_type){
2201                                 if (oper == Operator.BitwiseAnd ||
2202                                     oper == Operator.BitwiseOr ||
2203                                     oper == Operator.ExclusiveOr){
2204                                         type = l;
2205                                         return this;
2206                                 }
2207                         }
2208
2209                         //
2210                         // Pointer comparison
2211                         //
2212                         if (l.IsPointer && r.IsPointer){
2213                                 if (oper == Operator.Equality || oper == Operator.Inequality ||
2214                                     oper == Operator.LessThan || oper == Operator.LessThanOrEqual ||
2215                                     oper == Operator.GreaterThan || oper == Operator.GreaterThanOrEqual){
2216                                         type = TypeManager.bool_type;
2217                                         return this;
2218                                 }
2219                         }
2220
2221                         //
2222                         // We are dealing with numbers
2223                         //
2224                         if (overload_failed){
2225                                 Error_OperatorCannotBeApplied ();
2226                                 return null;
2227                         }
2228
2229                         //
2230                         // This will leave left or right set to null if there is an error
2231                         //
2232                         DoNumericPromotions (ec, l, r);
2233                         if (left == null || right == null){
2234                                 Error_OperatorCannotBeApplied (loc, OperName (oper), l, r);
2235                                 return null;
2236                         }
2237
2238                         //
2239                         // reload our cached types if required
2240                         //
2241                         l = left.Type;
2242                         r = right.Type;
2243
2244                         if (oper == Operator.BitwiseAnd ||
2245                             oper == Operator.BitwiseOr ||
2246                             oper == Operator.ExclusiveOr){
2247                                 if (l == r){
2248                                         if (!((l == TypeManager.int32_type) ||
2249                                               (l == TypeManager.uint32_type) ||
2250                                               (l == TypeManager.int64_type) ||
2251                                               (l == TypeManager.uint64_type)))
2252                                                 type = l;
2253                                 } else {
2254                                         Error_OperatorCannotBeApplied ();
2255                                         return null;
2256                                 }
2257                         }
2258
2259                         if (oper == Operator.Equality ||
2260                             oper == Operator.Inequality ||
2261                             oper == Operator.LessThanOrEqual ||
2262                             oper == Operator.LessThan ||
2263                             oper == Operator.GreaterThanOrEqual ||
2264                             oper == Operator.GreaterThan){
2265                                 type = TypeManager.bool_type;
2266                         }
2267
2268                         return this;
2269                 }
2270
2271                 public override Expression DoResolve (EmitContext ec)
2272                 {
2273                         left = left.Resolve (ec);
2274                         right = right.Resolve (ec);
2275
2276                         if (left == null || right == null)
2277                                 return null;
2278
2279                         if (left.Type == null)
2280                                 throw new Exception (
2281                                         "Resolve returned non null, but did not set the type! (" +
2282                                         left + ") at Line: " + loc.Row);
2283                         if (right.Type == null)
2284                                 throw new Exception (
2285                                         "Resolve returned non null, but did not set the type! (" +
2286                                         right + ") at Line: "+ loc.Row);
2287
2288                         eclass = ExprClass.Value;
2289
2290                         if (left is Constant && right is Constant){
2291                                 Expression e = ConstantFold.BinaryFold (
2292                                         ec, oper, (Constant) left, (Constant) right, loc);
2293                                 if (e != null)
2294                                         return e;
2295                         }
2296
2297                         return ResolveOperator (ec);
2298                 }
2299
2300                 /// <remarks>
2301                 ///   EmitBranchable is called from Statement.EmitBoolExpression in the
2302                 ///   context of a conditional bool expression.  This function will return
2303                 ///   false if it is was possible to use EmitBranchable, or true if it was.
2304                 ///
2305                 ///   The expression's code is generated, and we will generate a branch to `target'
2306                 ///   if the resulting expression value is equal to isTrue
2307                 /// </remarks>
2308                 public bool EmitBranchable (EmitContext ec, Label target, bool onTrue)
2309                 {
2310                         if (method != null)
2311                                 return false;
2312
2313                         ILGenerator ig = ec.ig;
2314
2315                         //
2316                         // This is more complicated than it looks, but its just to avoid
2317                         // duplicated tests: basically, we allow ==, !=, >, <, >= and <=
2318                         // but on top of that we want for == and != to use a special path
2319                         // if we are comparing against null
2320                         //
2321                         if (oper == Operator.Equality || oper == Operator.Inequality){
2322                                 bool my_on_true = oper == Operator.Inequality ? onTrue : !onTrue;
2323
2324                                 if (left is NullLiteral){
2325                                         right.Emit (ec);
2326                                         if (my_on_true)
2327                                                 ig.Emit (OpCodes.Brtrue, target);
2328                                         else
2329                                                 ig.Emit (OpCodes.Brfalse, target);
2330                                         return true;
2331                                 } else if (right is NullLiteral){
2332                                         left.Emit (ec);
2333                                         if (my_on_true)
2334                                                 ig.Emit (OpCodes.Brtrue, target);
2335                                         else
2336                                                 ig.Emit (OpCodes.Brfalse, target);
2337                                         return true;
2338                                 }
2339                         } else if (!(oper == Operator.LessThan ||
2340                                       oper == Operator.GreaterThan ||
2341                                       oper == Operator.LessThanOrEqual ||
2342                                       oper == Operator.GreaterThanOrEqual))
2343                                 return false;
2344
2345
2346
2347                         left.Emit (ec);
2348                         right.Emit (ec);
2349
2350                         bool isUnsigned = is_unsigned (left.Type);
2351
2352                         switch (oper){
2353                         case Operator.Equality:
2354                                 if (onTrue)
2355                                         ig.Emit (OpCodes.Beq, target);
2356                                 else
2357                                         ig.Emit (OpCodes.Bne_Un, target);
2358                                 break;
2359
2360                         case Operator.Inequality:
2361                                 if (onTrue)
2362                                         ig.Emit (OpCodes.Bne_Un, target);
2363                                 else
2364                                         ig.Emit (OpCodes.Beq, target);
2365                                 break;
2366
2367                         case Operator.LessThan:
2368                                 if (onTrue)
2369                                         if (isUnsigned)
2370                                                 ig.Emit (OpCodes.Blt_Un, target);
2371                                         else
2372                                                 ig.Emit (OpCodes.Blt, target);
2373                                 else
2374                                         if (isUnsigned)
2375                                                 ig.Emit (OpCodes.Bge_Un, target);
2376                                         else
2377                                                 ig.Emit (OpCodes.Bge, target);
2378                                 break;
2379
2380                         case Operator.GreaterThan:
2381                                 if (onTrue)
2382                                         if (isUnsigned)
2383                                                 ig.Emit (OpCodes.Bgt_Un, target);
2384                                         else
2385                                                 ig.Emit (OpCodes.Bgt, target);
2386                                 else
2387                                         if (isUnsigned)
2388                                                 ig.Emit (OpCodes.Ble_Un, target);
2389                                         else
2390                                                 ig.Emit (OpCodes.Ble, target);
2391                                 break;
2392
2393                         case Operator.LessThanOrEqual:
2394                                 if (onTrue)
2395                                         if (isUnsigned)
2396                                                 ig.Emit (OpCodes.Ble_Un, target);
2397                                         else
2398                                                 ig.Emit (OpCodes.Ble, target);
2399                                 else
2400                                         if (isUnsigned)
2401                                                 ig.Emit (OpCodes.Bgt_Un, target);
2402                                         else
2403                                                 ig.Emit (OpCodes.Bgt, target);
2404                                 break;
2405
2406
2407                         case Operator.GreaterThanOrEqual:
2408                                 if (onTrue)
2409                                         if (isUnsigned)
2410                                                 ig.Emit (OpCodes.Bge_Un, target);
2411                                         else
2412                                                 ig.Emit (OpCodes.Bge, target);
2413                                 else
2414                                         if (isUnsigned)
2415                                                 ig.Emit (OpCodes.Blt_Un, target);
2416                                         else
2417                                                 ig.Emit (OpCodes.Blt, target);
2418                                 break;
2419
2420                         default:
2421                                 return false;
2422                         }
2423
2424                         return true;
2425                 }
2426
2427                 public override void Emit (EmitContext ec)
2428                 {
2429                         ILGenerator ig = ec.ig;
2430                         Type l = left.Type;
2431                         Type r = right.Type;
2432                         OpCode opcode;
2433
2434                         if (method != null) {
2435
2436                                 // Note that operators are static anyway
2437
2438                                 if (Arguments != null)
2439                                         Invocation.EmitArguments (ec, method, Arguments);
2440
2441                                 if (method is MethodInfo)
2442                                         ig.Emit (OpCodes.Call, (MethodInfo) method);
2443                                 else
2444                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
2445
2446                                 if (DelegateOperation)
2447                                         ig.Emit (OpCodes.Castclass, type);
2448
2449                                 return;
2450                         }
2451
2452                         //
2453                         // Handle short-circuit operators differently
2454                         // than the rest
2455                         //
2456                         if (oper == Operator.LogicalAnd){
2457                                 Label load_zero = ig.DefineLabel ();
2458                                 Label end = ig.DefineLabel ();
2459
2460                                 left.Emit (ec);
2461                                 ig.Emit (OpCodes.Brfalse, load_zero);
2462                                 right.Emit (ec);
2463                                 ig.Emit (OpCodes.Br, end);
2464                                 ig.MarkLabel (load_zero);
2465                                 ig.Emit (OpCodes.Ldc_I4_0);
2466                                 ig.MarkLabel (end);
2467                                 return;
2468                         } else if (oper == Operator.LogicalOr){
2469                                 Label load_one = ig.DefineLabel ();
2470                                 Label end = ig.DefineLabel ();
2471
2472                                 left.Emit (ec);
2473                                 ig.Emit (OpCodes.Brtrue, load_one);
2474                                 right.Emit (ec);
2475                                 ig.Emit (OpCodes.Br, end);
2476                                 ig.MarkLabel (load_one);
2477                                 ig.Emit (OpCodes.Ldc_I4_1);
2478                                 ig.MarkLabel (end);
2479                                 return;
2480                         }
2481
2482                         left.Emit (ec);
2483                         right.Emit (ec);
2484
2485                         switch (oper){
2486                         case Operator.Multiply:
2487                                 if (ec.CheckState){
2488                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2489                                                 opcode = OpCodes.Mul_Ovf;
2490                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2491                                                 opcode = OpCodes.Mul_Ovf_Un;
2492                                         else
2493                                                 opcode = OpCodes.Mul;
2494                                 } else
2495                                         opcode = OpCodes.Mul;
2496
2497                                 break;
2498
2499                         case Operator.Division:
2500                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2501                                         opcode = OpCodes.Div_Un;
2502                                 else
2503                                         opcode = OpCodes.Div;
2504                                 break;
2505
2506                         case Operator.Modulus:
2507                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2508                                         opcode = OpCodes.Rem_Un;
2509                                 else
2510                                         opcode = OpCodes.Rem;
2511                                 break;
2512
2513                         case Operator.Addition:
2514                                 if (ec.CheckState){
2515                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2516                                                 opcode = OpCodes.Add_Ovf;
2517                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2518                                                 opcode = OpCodes.Add_Ovf_Un;
2519                                         else
2520                                                 opcode = OpCodes.Add;
2521                                 } else
2522                                         opcode = OpCodes.Add;
2523                                 break;
2524
2525                         case Operator.Subtraction:
2526                                 if (ec.CheckState){
2527                                         if (l == TypeManager.int32_type || l == TypeManager.int64_type)
2528                                                 opcode = OpCodes.Sub_Ovf;
2529                                         else if (l==TypeManager.uint32_type || l==TypeManager.uint64_type)
2530                                                 opcode = OpCodes.Sub_Ovf_Un;
2531                                         else
2532                                                 opcode = OpCodes.Sub;
2533                                 } else
2534                                         opcode = OpCodes.Sub;
2535                                 break;
2536
2537                         case Operator.RightShift:
2538                                 if (l == TypeManager.uint32_type || l == TypeManager.uint64_type)
2539                                         opcode = OpCodes.Shr_Un;
2540                                 else
2541                                         opcode = OpCodes.Shr;
2542                                 break;
2543
2544                         case Operator.LeftShift:
2545                                 opcode = OpCodes.Shl;
2546                                 break;
2547
2548                         case Operator.Equality:
2549                                 opcode = OpCodes.Ceq;
2550                                 break;
2551
2552                         case Operator.Inequality:
2553                                 ec.ig.Emit (OpCodes.Ceq);
2554                                 ec.ig.Emit (OpCodes.Ldc_I4_0);
2555
2556                                 opcode = OpCodes.Ceq;
2557                                 break;
2558
2559                         case Operator.LessThan:
2560                                 opcode = OpCodes.Clt;
2561                                 break;
2562
2563                         case Operator.GreaterThan:
2564                                 opcode = OpCodes.Cgt;
2565                                 break;
2566
2567                         case Operator.LessThanOrEqual:
2568                                 ec.ig.Emit (OpCodes.Cgt);
2569                                 ec.ig.Emit (OpCodes.Ldc_I4_0);
2570
2571                                 opcode = OpCodes.Ceq;
2572                                 break;
2573
2574                         case Operator.GreaterThanOrEqual:
2575                                 ec.ig.Emit (OpCodes.Clt);
2576                                 ec.ig.Emit (OpCodes.Ldc_I4_1);
2577
2578                                 opcode = OpCodes.Sub;
2579                                 break;
2580
2581                         case Operator.BitwiseOr:
2582                                 opcode = OpCodes.Or;
2583                                 break;
2584
2585                         case Operator.BitwiseAnd:
2586                                 opcode = OpCodes.And;
2587                                 break;
2588
2589                         case Operator.ExclusiveOr:
2590                                 opcode = OpCodes.Xor;
2591                                 break;
2592
2593                         default:
2594                                 throw new Exception ("This should not happen: Operator = "
2595                                                      + oper.ToString ());
2596                         }
2597
2598                         ig.Emit (opcode);
2599                 }
2600
2601                 public bool IsBuiltinOperator {
2602                         get {
2603                                 return method == null;
2604                         }
2605                 }
2606         }
2607
2608         public class PointerArithmetic : Expression {
2609                 Expression left, right;
2610                 bool is_add;
2611
2612                 //
2613                 // We assume that `l' is always a pointer
2614                 //
2615                 public PointerArithmetic (bool is_addition, Expression l, Expression r, Type t,
2616                                           Location loc)
2617                 {
2618                         type = t;
2619                         eclass = ExprClass.Variable;
2620                         this.loc = loc;
2621                         left = l;
2622                         right = r;
2623                         is_add = is_addition;
2624                 }
2625
2626                 public override Expression DoResolve (EmitContext ec)
2627                 {
2628                         //
2629                         // We are born fully resolved
2630                         //
2631                         return this;
2632                 }
2633
2634                 public override void Emit (EmitContext ec)
2635                 {
2636                         Type op_type = left.Type;
2637                         ILGenerator ig = ec.ig;
2638                         int size = GetTypeSize (op_type.GetElementType ());
2639
2640                         if (right.Type.IsPointer){
2641                                 //
2642                                 // handle (pointer - pointer)
2643                                 //
2644                                 left.Emit (ec);
2645                                 right.Emit (ec);
2646                                 ig.Emit (OpCodes.Sub);
2647
2648                                 if (size != 1){
2649                                         if (size == 0)
2650                                                 ig.Emit (OpCodes.Sizeof, op_type);
2651                                         else
2652                                                 IntLiteral.EmitInt (ig, size);
2653                                         ig.Emit (OpCodes.Div);
2654                                 }
2655                                 ig.Emit (OpCodes.Conv_I8);
2656                         } else {
2657                                 //
2658                                 // handle + and - on (pointer op int)
2659                                 //
2660                                 left.Emit (ec);
2661                                 ig.Emit (OpCodes.Conv_I);
2662                                 right.Emit (ec);
2663                                 if (size != 1){
2664                                         if (size == 0)
2665                                                 ig.Emit (OpCodes.Sizeof, op_type);
2666                                         else
2667                                                 IntLiteral.EmitInt (ig, size);
2668                                         ig.Emit (OpCodes.Mul);
2669                                 }
2670                                 if (is_add)
2671                                         ig.Emit (OpCodes.Add);
2672                                 else
2673                                         ig.Emit (OpCodes.Sub);
2674                         }
2675                 }
2676         }
2677
2678         /// <summary>
2679         ///   Implements the ternary conditional operator (?:)
2680         /// </summary>
2681         public class Conditional : Expression {
2682                 Expression expr, trueExpr, falseExpr;
2683
2684                 public Conditional (Expression expr, Expression trueExpr, Expression falseExpr, Location l)
2685                 {
2686                         this.expr = expr;
2687                         this.trueExpr = trueExpr;
2688                         this.falseExpr = falseExpr;
2689                         this.loc = l;
2690                 }
2691
2692                 public Expression Expr {
2693                         get {
2694                                 return expr;
2695                         }
2696                 }
2697
2698                 public Expression TrueExpr {
2699                         get {
2700                                 return trueExpr;
2701                         }
2702                 }
2703
2704                 public Expression FalseExpr {
2705                         get {
2706                                 return falseExpr;
2707                         }
2708                 }
2709
2710                 public override Expression DoResolve (EmitContext ec)
2711                 {
2712                         expr = expr.Resolve (ec);
2713
2714                         if (expr == null)
2715                                 return null;
2716
2717                         if (expr.Type != TypeManager.bool_type)
2718                                 expr = Expression.ConvertImplicitRequired (
2719                                         ec, expr, TypeManager.bool_type, loc);
2720
2721                         trueExpr = trueExpr.Resolve (ec);
2722                         falseExpr = falseExpr.Resolve (ec);
2723
2724                         if (trueExpr == null || falseExpr == null)
2725                                 return null;
2726
2727                         eclass = ExprClass.Value;
2728                         if (trueExpr.Type == falseExpr.Type)
2729                                 type = trueExpr.Type;
2730                         else {
2731                                 Expression conv;
2732                                 Type true_type = trueExpr.Type;
2733                                 Type false_type = falseExpr.Type;
2734
2735                                 if (trueExpr is NullLiteral){
2736                                         type = false_type;
2737                                         return this;
2738                                 } else if (falseExpr is NullLiteral){
2739                                         type = true_type;
2740                                         return this;
2741                                 }
2742
2743                                 //
2744                                 // First, if an implicit conversion exists from trueExpr
2745                                 // to falseExpr, then the result type is of type falseExpr.Type
2746                                 //
2747                                 conv = ConvertImplicit (ec, trueExpr, false_type, loc);
2748                                 if (conv != null){
2749                                         //
2750                                         // Check if both can convert implicitl to each other's type
2751                                         //
2752                                         if (ConvertImplicit (ec, falseExpr, true_type, loc) != null){
2753                                                 Error (172,
2754                                                        "Can not compute type of conditional expression " +
2755                                                        "as `" + TypeManager.CSharpName (trueExpr.Type) +
2756                                                        "' and `" + TypeManager.CSharpName (falseExpr.Type) +
2757                                                        "' convert implicitly to each other");
2758                                                 return null;
2759                                         }
2760                                         type = false_type;
2761                                         trueExpr = conv;
2762                                 } else if ((conv = ConvertImplicit(ec, falseExpr, true_type,loc))!= null){
2763                                         type = true_type;
2764                                         falseExpr = conv;
2765                                 } else {
2766                                         Error (173, "The type of the conditional expression can " +
2767                                                "not be computed because there is no implicit conversion" +
2768                                                " from `" + TypeManager.CSharpName (trueExpr.Type) + "'" +
2769                                                " and `" + TypeManager.CSharpName (falseExpr.Type) + "'");
2770                                         return null;
2771                                 }
2772                         }
2773
2774                         if (expr is BoolConstant){
2775                                 BoolConstant bc = (BoolConstant) expr;
2776
2777                                 if (bc.Value)
2778                                         return trueExpr;
2779                                 else
2780                                         return falseExpr;
2781                         }
2782
2783                         return this;
2784                 }
2785
2786                 public override void Emit (EmitContext ec)
2787                 {
2788                         ILGenerator ig = ec.ig;
2789                         Label false_target = ig.DefineLabel ();
2790                         Label end_target = ig.DefineLabel ();
2791
2792                         Statement.EmitBoolExpression (ec, expr, false_target, false);
2793                         trueExpr.Emit (ec);
2794                         ig.Emit (OpCodes.Br, end_target);
2795                         ig.MarkLabel (false_target);
2796                         falseExpr.Emit (ec);
2797                         ig.MarkLabel (end_target);
2798                 }
2799
2800         }
2801
2802         /// <summary>
2803         ///   Local variables
2804         /// </summary>
2805         public class LocalVariableReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
2806                 public readonly string Name;
2807                 public readonly Block Block;
2808                 VariableInfo variable_info;
2809                 bool is_readonly;
2810
2811                 public LocalVariableReference (Block block, string name, Location l)
2812                 {
2813                         Block = block;
2814                         Name = name;
2815                         loc = l;
2816                         eclass = ExprClass.Variable;
2817                 }
2818
2819                 // Setting `is_readonly' to false will allow you to create a writable
2820                 // reference to a read-only variable.  This is used by foreach and using.
2821                 public LocalVariableReference (Block block, string name, Location l,
2822                                                VariableInfo variable_info, bool is_readonly)
2823                         : this (block, name, l)
2824                 {
2825                         this.variable_info = variable_info;
2826                         this.is_readonly = is_readonly;
2827                 }
2828
2829                 public VariableInfo VariableInfo {
2830                         get {
2831                                 if (variable_info == null) {
2832                                         variable_info = Block.GetVariableInfo (Name);
2833                                         is_readonly = variable_info.ReadOnly;
2834                                 }
2835                                 return variable_info;
2836                         }
2837                 }
2838
2839                 public bool IsAssigned (EmitContext ec, Location loc)
2840                 {
2841                         return VariableInfo.IsAssigned (ec, loc);
2842                 }
2843
2844                 public bool IsFieldAssigned (EmitContext ec, string name, Location loc)
2845                 {
2846                         return VariableInfo.IsFieldAssigned (ec, name, loc);
2847                 }
2848
2849                 public void SetAssigned (EmitContext ec)
2850                 {
2851                         VariableInfo.SetAssigned (ec);
2852                 }
2853
2854                 public void SetFieldAssigned (EmitContext ec, string name)
2855                 {
2856                         VariableInfo.SetFieldAssigned (ec, name);
2857                 }
2858
2859                 public bool IsReadOnly {
2860                         get {
2861                                 if (variable_info == null) {
2862                                         variable_info = Block.GetVariableInfo (Name);
2863                                         is_readonly = variable_info.ReadOnly;
2864                                 }
2865                                 return is_readonly;
2866                         }
2867                 }
2868
2869                 public override Expression DoResolve (EmitContext ec)
2870                 {
2871                         VariableInfo vi = VariableInfo;
2872
2873                         if (Block.IsConstant (Name)) {
2874                                 Expression e = Block.GetConstantExpression (Name);
2875
2876                                 vi.Used = true;
2877                                 return e;
2878                         }
2879
2880                         if (ec.DoFlowAnalysis && !IsAssigned (ec, loc))
2881                                 return null;
2882
2883                         type = vi.VariableType;
2884                         return this;
2885                 }
2886
2887                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
2888                 {
2889                         VariableInfo vi = VariableInfo;
2890
2891                         if (ec.DoFlowAnalysis)
2892                                 ec.SetVariableAssigned (vi);
2893
2894                         Expression e = DoResolve (ec);
2895
2896                         if (e == null)
2897                                 return null;
2898
2899                         if (is_readonly){
2900                                 Error (1604, "cannot assign to `" + Name + "' because it is readonly");
2901                                 return null;
2902                         }
2903
2904                         return this;
2905                 }
2906
2907                 public override void Emit (EmitContext ec)
2908                 {
2909                         VariableInfo vi = VariableInfo;
2910                         ILGenerator ig = ec.ig;
2911
2912                         ig.Emit (OpCodes.Ldloc, vi.LocalBuilder);
2913                         vi.Used = true;
2914                 }
2915
2916                 public void EmitAssign (EmitContext ec, Expression source)
2917                 {
2918                         ILGenerator ig = ec.ig;
2919                         VariableInfo vi = VariableInfo;
2920
2921                         vi.Assigned = true;
2922
2923                         source.Emit (ec);
2924
2925                         ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
2926                 }
2927
2928                 public void AddressOf (EmitContext ec, AddressOp mode)
2929                 {
2930                         VariableInfo vi = VariableInfo;
2931
2932                         ec.ig.Emit (OpCodes.Ldloca, vi.LocalBuilder);
2933                 }
2934         }
2935
2936         /// <summary>
2937         ///   This represents a reference to a parameter in the intermediate
2938         ///   representation.
2939         /// </summary>
2940         public class ParameterReference : Expression, IAssignMethod, IMemoryLocation, IVariable {
2941                 Parameters pars;
2942                 String name;
2943                 int idx;
2944                 public Parameter.Modifier mod;
2945                 public bool is_ref, is_out;
2946
2947                 public ParameterReference (Parameters pars, int idx, string name, Location loc)
2948                 {
2949                         this.pars = pars;
2950                         this.idx  = idx;
2951                         this.name = name;
2952                         this.loc = loc;
2953                         eclass = ExprClass.Variable;
2954                 }
2955
2956                 public bool IsAssigned (EmitContext ec, Location loc)
2957                 {
2958                         if (!is_out || !ec.DoFlowAnalysis)
2959                                 return true;
2960
2961                         if (!ec.CurrentBranching.IsParameterAssigned (idx)) {
2962                                 Report.Error (165, loc,
2963                                               "Use of unassigned local variable `" + name + "'");
2964                                 return false;
2965                         }
2966
2967                         return true;
2968                 }
2969
2970                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
2971                 {
2972                         if (!is_out || !ec.DoFlowAnalysis)
2973                                 return true;
2974
2975                         if (ec.CurrentBranching.IsParameterAssigned (idx))
2976                                 return true;
2977
2978                         if (!ec.CurrentBranching.IsParameterAssigned (idx, field_name)) {
2979                                 Report.Error (170, loc,
2980                                               "Use of possibly unassigned field `" + field_name + "'");
2981                                 return false;
2982                         }
2983
2984                         return true;
2985                 }
2986
2987                 public void SetAssigned (EmitContext ec)
2988                 {
2989                         if (is_out && ec.DoFlowAnalysis)
2990                                 ec.CurrentBranching.SetParameterAssigned (idx);
2991                 }
2992
2993                 public void SetFieldAssigned (EmitContext ec, string field_name)
2994                 {
2995                         if (is_out && ec.DoFlowAnalysis)
2996                                 ec.CurrentBranching.SetParameterAssigned (idx, field_name);
2997                 }
2998
2999                 //
3000                 // Notice that for ref/out parameters, the type exposed is not the
3001                 // same type exposed externally.
3002                 //
3003                 // for "ref int a":
3004                 //   externally we expose "int&"
3005                 //   here we expose       "int".
3006                 //
3007                 // We record this in "is_ref".  This means that the type system can treat
3008                 // the type as it is expected, but when we generate the code, we generate
3009                 // the alternate kind of code.
3010                 //
3011                 public override Expression DoResolve (EmitContext ec)
3012                 {
3013                         type = pars.GetParameterInfo (ec.DeclSpace, idx, out mod);
3014                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3015                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3016                         eclass = ExprClass.Variable;
3017
3018                         if (is_out && ec.DoFlowAnalysis && !IsAssigned (ec, loc))
3019                                 return null;
3020
3021                         return this;
3022                 }
3023
3024                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3025                 {
3026                         type = pars.GetParameterInfo (ec.DeclSpace, idx, out mod);
3027                         is_ref = (mod & Parameter.Modifier.ISBYREF) != 0;
3028                         is_out = (mod & Parameter.Modifier.OUT) != 0;
3029                         eclass = ExprClass.Variable;
3030
3031                         if (is_out && ec.DoFlowAnalysis)
3032                                 ec.SetParameterAssigned (idx);
3033
3034                         return this;
3035                 }
3036
3037                 static void EmitLdArg (ILGenerator ig, int x)
3038                 {
3039                         if (x <= 255){
3040                                 switch (x){
3041                                 case 0: ig.Emit (OpCodes.Ldarg_0); break;
3042                                 case 1: ig.Emit (OpCodes.Ldarg_1); break;
3043                                 case 2: ig.Emit (OpCodes.Ldarg_2); break;
3044                                 case 3: ig.Emit (OpCodes.Ldarg_3); break;
3045                                 default: ig.Emit (OpCodes.Ldarg_S, (byte) x); break;
3046                                 }
3047                         } else
3048                                 ig.Emit (OpCodes.Ldarg, x);
3049                 }
3050
3051                 //
3052                 // This method is used by parameters that are references, that are
3053                 // being passed as references:  we only want to pass the pointer (that
3054                 // is already stored in the parameter, not the address of the pointer,
3055                 // and not the value of the variable).
3056                 //
3057                 public void EmitLoad (EmitContext ec)
3058                 {
3059                         ILGenerator ig = ec.ig;
3060                         int arg_idx = idx;
3061
3062                         if (!ec.IsStatic)
3063                                 arg_idx++;
3064
3065                         EmitLdArg (ig, arg_idx);
3066                 }
3067
3068                 public override void Emit (EmitContext ec)
3069                 {
3070                         ILGenerator ig = ec.ig;
3071                         int arg_idx = idx;
3072
3073                         if (!ec.IsStatic)
3074                                 arg_idx++;
3075
3076                         EmitLdArg (ig, arg_idx);
3077
3078                         if (!is_ref)
3079                                 return;
3080
3081                         //
3082                         // If we are a reference, we loaded on the stack a pointer
3083                         // Now lets load the real value
3084                         //
3085                         LoadFromPtr (ig, type);
3086                 }
3087
3088                 public void EmitAssign (EmitContext ec, Expression source)
3089                 {
3090                         ILGenerator ig = ec.ig;
3091                         int arg_idx = idx;
3092
3093                         if (!ec.IsStatic)
3094                                 arg_idx++;
3095
3096                         if (is_ref)
3097                                 EmitLdArg (ig, arg_idx);
3098
3099                         source.Emit (ec);
3100
3101                         if (is_ref)
3102                                 StoreFromPtr (ig, type);
3103                         else {
3104                                 if (arg_idx <= 255)
3105                                         ig.Emit (OpCodes.Starg_S, (byte) arg_idx);
3106                                 else
3107                                         ig.Emit (OpCodes.Starg, arg_idx);
3108                         }
3109                 }
3110
3111                 public void AddressOf (EmitContext ec, AddressOp mode)
3112                 {
3113                         int arg_idx = idx;
3114
3115                         if (!ec.IsStatic)
3116                                 arg_idx++;
3117
3118                         if (is_ref){
3119                                 if (arg_idx <= 255)
3120                                         ec.ig.Emit (OpCodes.Ldarg_S, (byte) arg_idx);
3121                                 else
3122                                         ec.ig.Emit (OpCodes.Ldarg, arg_idx);
3123                         } else {
3124                                 if (arg_idx <= 255)
3125                                         ec.ig.Emit (OpCodes.Ldarga_S, (byte) arg_idx);
3126                                 else
3127                                         ec.ig.Emit (OpCodes.Ldarga, arg_idx);
3128                         }
3129                 }
3130         }
3131
3132         /// <summary>
3133         ///   Used for arguments to New(), Invocation()
3134         /// </summary>
3135         public class Argument {
3136                 public enum AType : byte {
3137                         Expression,
3138                         Ref,
3139                         Out
3140                 };
3141
3142                 public readonly AType ArgType;
3143                 public Expression Expr;
3144
3145                 public Argument (Expression expr, AType type)
3146                 {
3147                         this.Expr = expr;
3148                         this.ArgType = type;
3149                 }
3150
3151                 public Type Type {
3152                         get {
3153                                 if (ArgType == AType.Ref || ArgType == AType.Out)
3154                                         return TypeManager.LookupType (Expr.Type.ToString () + "&");
3155                                 else
3156                                         return Expr.Type;
3157                         }
3158                 }
3159
3160                 public Parameter.Modifier GetParameterModifier ()
3161                 {
3162                         switch (ArgType) {
3163                         case AType.Out:
3164                                 return Parameter.Modifier.OUT | Parameter.Modifier.ISBYREF;
3165
3166                         case AType.Ref:
3167                                 return Parameter.Modifier.REF | Parameter.Modifier.ISBYREF;
3168
3169                         default:
3170                                 return Parameter.Modifier.NONE;
3171                         }
3172                 }
3173
3174                 public static string FullDesc (Argument a)
3175                 {
3176                         return (a.ArgType == AType.Ref ? "ref " :
3177                                 (a.ArgType == AType.Out ? "out " : "")) +
3178                                 TypeManager.CSharpName (a.Expr.Type);
3179                 }
3180
3181                 public bool ResolveMethodGroup (EmitContext ec, Location loc)
3182                 {
3183                         // FIXME: csc doesn't report any error if you try to use `ref' or
3184                         //        `out' in a delegate creation expression.
3185                         Expr = Expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
3186                         if (Expr == null)
3187                                 return false;
3188
3189                         return true;
3190                 }
3191
3192                 public bool Resolve (EmitContext ec, Location loc)
3193                 {
3194                         if (ArgType == AType.Ref) {
3195                                 Expr = Expr.Resolve (ec);
3196                                 if (Expr == null)
3197                                         return false;
3198
3199                                 Expr = Expr.ResolveLValue (ec, Expr);
3200                         } else if (ArgType == AType.Out)
3201                                 Expr = Expr.ResolveLValue (ec, new EmptyExpression ());
3202                         else
3203                                 Expr = Expr.Resolve (ec);
3204
3205                         if (Expr == null)
3206                                 return false;
3207
3208                         if (ArgType == AType.Expression)
3209                                 return true;
3210
3211                         if (Expr.eclass != ExprClass.Variable){
3212                                 //
3213                                 // We just probe to match the CSC output
3214                                 //
3215                                 if (Expr.eclass == ExprClass.PropertyAccess ||
3216                                     Expr.eclass == ExprClass.IndexerAccess){
3217                                         Report.Error (
3218                                                 206, loc,
3219                                                 "A property or indexer can not be passed as an out or ref " +
3220                                                 "parameter");
3221                                 } else {
3222                                         Report.Error (
3223                                                 1510, loc,
3224                                                 "An lvalue is required as an argument to out or ref");
3225                                 }
3226                                 return false;
3227                         }
3228
3229                         return true;
3230                 }
3231
3232                 public void Emit (EmitContext ec)
3233                 {
3234                         //
3235                         // Ref and Out parameters need to have their addresses taken.
3236                         //
3237                         // ParameterReferences might already be references, so we want
3238                         // to pass just the value
3239                         //
3240                         if (ArgType == AType.Ref || ArgType == AType.Out){
3241                                 AddressOp mode = AddressOp.Store;
3242
3243                                 if (ArgType == AType.Ref)
3244                                         mode |= AddressOp.Load;
3245
3246                                 if (Expr is ParameterReference){
3247                                         ParameterReference pr = (ParameterReference) Expr;
3248
3249                                         if (pr.is_ref)
3250                                                 pr.EmitLoad (ec);
3251                                         else {
3252
3253                                                 pr.AddressOf (ec, mode);
3254                                         }
3255                                 } else
3256                                         ((IMemoryLocation)Expr).AddressOf (ec, mode);
3257                         } else
3258                                 Expr.Emit (ec);
3259                 }
3260         }
3261
3262         /// <summary>
3263         ///   Invocation of methods or delegates.
3264         /// </summary>
3265         public class Invocation : ExpressionStatement {
3266                 public readonly ArrayList Arguments;
3267
3268                 Expression expr;
3269                 MethodBase method = null;
3270                 bool is_base;
3271
3272                 static Hashtable method_parameter_cache;
3273
3274                 static Invocation ()
3275                 {
3276                         method_parameter_cache = new PtrHashtable ();
3277                 }
3278
3279                 //
3280                 // arguments is an ArrayList, but we do not want to typecast,
3281                 // as it might be null.
3282                 //
3283                 // FIXME: only allow expr to be a method invocation or a
3284                 // delegate invocation (7.5.5)
3285                 //
3286                 public Invocation (Expression expr, ArrayList arguments, Location l)
3287                 {
3288                         this.expr = expr;
3289                         Arguments = arguments;
3290                         loc = l;
3291                 }
3292
3293                 public Expression Expr {
3294                         get {
3295                                 return expr;
3296                         }
3297                 }
3298
3299                 /// <summary>
3300                 ///   Returns the Parameters (a ParameterData interface) for the
3301                 ///   Method `mb'
3302                 /// </summary>
3303                 public static ParameterData GetParameterData (MethodBase mb)
3304                 {
3305                         object pd = method_parameter_cache [mb];
3306                         object ip;
3307
3308                         if (pd != null)
3309                                 return (ParameterData) pd;
3310
3311
3312                         ip = TypeManager.LookupParametersByBuilder (mb);
3313                         if (ip != null){
3314                                 method_parameter_cache [mb] = ip;
3315
3316                                 return (ParameterData) ip;
3317                         } else {
3318                                 ParameterInfo [] pi = mb.GetParameters ();
3319                                 ReflectionParameters rp = new ReflectionParameters (pi);
3320                                 method_parameter_cache [mb] = rp;
3321
3322                                 return (ParameterData) rp;
3323                         }
3324                 }
3325
3326                 /// <summary>
3327                 ///  Determines "better conversion" as specified in 7.4.2.3
3328                 ///  Returns : 1 if a->p is better
3329                 ///            0 if a->q or neither is better
3330                 /// </summary>
3331                 static int BetterConversion (EmitContext ec, Argument a, Type p, Type q, Location loc)
3332                 {
3333                         Type argument_type = a.Type;
3334                         Expression argument_expr = a.Expr;
3335
3336                         if (argument_type == null)
3337                                 throw new Exception ("Expression of type " + a.Expr + " does not resolve its type");
3338
3339                         //
3340                         // This is a special case since csc behaves this way. I can't find
3341                         // it anywhere in the spec but oh well ...
3342                         //
3343                         if (argument_expr is NullLiteral && p == TypeManager.string_type && q == TypeManager.object_type)
3344                                 return 1;
3345                         else if (argument_expr is NullLiteral && p == TypeManager.object_type && q == TypeManager.string_type)
3346                                 return 0;
3347
3348                         if (p == q)
3349                                 return 0;
3350
3351                         if (argument_type == p)
3352                                 return 1;
3353
3354                         if (argument_type == q)
3355                                 return 0;
3356
3357                         //
3358                         // Now probe whether an implicit constant expression conversion
3359                         // can be used.
3360                         //
3361                         // An implicit constant expression conversion permits the following
3362                         // conversions:
3363                         //
3364                         //    * A constant-expression of type `int' can be converted to type
3365                         //      sbyte, byute, short, ushort, uint, ulong provided the value of
3366                         //      of the expression is withing the range of the destination type.
3367                         //
3368                         //    * A constant-expression of type long can be converted to type
3369                         //      ulong, provided the value of the constant expression is not negative
3370                         //
3371                         // FIXME: Note that this assumes that constant folding has
3372                         // taken place.  We dont do constant folding yet.
3373                         //
3374
3375                         if (argument_expr is IntConstant){
3376                                 IntConstant ei = (IntConstant) argument_expr;
3377                                 int value = ei.Value;
3378
3379                                 if (p == TypeManager.sbyte_type){
3380                                         if (value >= SByte.MinValue && value <= SByte.MaxValue)
3381                                                 return 1;
3382                                 } else if (p == TypeManager.byte_type){
3383                                         if (Byte.MinValue >= 0 && value <= Byte.MaxValue)
3384                                                 return 1;
3385                                 } else if (p == TypeManager.short_type){
3386                                         if (value >= Int16.MinValue && value <= Int16.MaxValue)
3387                                                 return 1;
3388                                 } else if (p == TypeManager.ushort_type){
3389                                         if (value >= UInt16.MinValue && value <= UInt16.MaxValue)
3390                                                 return 1;
3391                                 } else if (p == TypeManager.uint32_type){
3392                                         //
3393                                         // we can optimize this case: a positive int32
3394                                         // always fits on a uint32
3395                                         //
3396                                         if (value >= 0)
3397                                                 return 1;
3398                                 } else if (p == TypeManager.uint64_type){
3399                                         //
3400                                         // we can optimize this case: a positive int32
3401                                         // always fits on a uint64
3402                                         //
3403                                         if (value >= 0)
3404                                                 return 1;
3405                                 }
3406                         } else if (argument_type == TypeManager.int64_type && argument_expr is LongConstant){
3407                                 LongConstant lc = (LongConstant) argument_expr;
3408
3409                                 if (p == TypeManager.uint64_type){
3410                                         if (lc.Value > 0)
3411                                                 return 1;
3412                                 }
3413                         }
3414
3415                         if (q == null) {
3416                                 Expression tmp = ConvertImplicit (ec, argument_expr, p, loc);
3417
3418                                 if (tmp != null)
3419                                         return 1;
3420                                 else
3421                                         return 0;
3422                         }
3423
3424                         Expression p_tmp = new EmptyExpression (p);
3425                         Expression q_tmp = new EmptyExpression (q);
3426
3427                         if (StandardConversionExists (p_tmp, q) == true &&
3428                             StandardConversionExists (q_tmp, p) == false)
3429                                 return 1;
3430
3431                         if (p == TypeManager.sbyte_type)
3432                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3433                                     q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3434                                         return 1;
3435
3436                         if (p == TypeManager.short_type)
3437                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3438                                     q == TypeManager.uint64_type)
3439                                         return 1;
3440
3441                         if (p == TypeManager.int32_type)
3442                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3443                                         return 1;
3444
3445                         if (p == TypeManager.int64_type)
3446                                 if (q == TypeManager.uint64_type)
3447                                         return 1;
3448
3449                         return 0;
3450                 }
3451
3452                 /// <summary>
3453                 ///  Determines "Better function"
3454                 /// </summary>
3455                 /// <remarks>
3456                 ///    and returns an integer indicating :
3457                 ///    0 if candidate ain't better
3458                 ///    1 if candidate is better than the current best match
3459                 /// </remarks>
3460                 static int BetterFunction (EmitContext ec, ArrayList args,
3461                                            MethodBase candidate, MethodBase best,
3462                                            bool expanded_form, Location loc)
3463                 {
3464                         ParameterData candidate_pd = GetParameterData (candidate);
3465                         ParameterData best_pd;
3466                         int argument_count;
3467
3468                         if (args == null)
3469                                 argument_count = 0;
3470                         else
3471                                 argument_count = args.Count;
3472
3473                         int cand_count = candidate_pd.Count;
3474
3475                         if (cand_count == 0 && argument_count == 0)
3476                                 return 1;
3477
3478                         if (candidate_pd.ParameterModifier (cand_count - 1) != Parameter.Modifier.PARAMS)
3479                                 if (cand_count != argument_count)
3480                                         return 0;
3481
3482                         if (best == null) {
3483                                 int x = 0;
3484
3485                                 if (argument_count == 0 && cand_count == 1 &&
3486                                     candidate_pd.ParameterModifier (cand_count - 1) == Parameter.Modifier.PARAMS)
3487                                         return 1;
3488
3489                                 for (int j = argument_count; j > 0;) {
3490                                         j--;
3491
3492                                         Argument a = (Argument) args [j];
3493                                         Type t = candidate_pd.ParameterType (j);
3494
3495                                         if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3496                                                 if (expanded_form)
3497                                                         t = t.GetElementType ();
3498
3499                                         x = BetterConversion (ec, a, t, null, loc);
3500
3501                                         if (x <= 0)
3502                                                 break;
3503                                 }
3504
3505                                 if (x > 0)
3506                                         return 1;
3507                                 else
3508                                         return 0;
3509                         }
3510
3511                         best_pd = GetParameterData (best);
3512
3513                         int rating1 = 0, rating2 = 0;
3514
3515                         for (int j = 0; j < argument_count; ++j) {
3516                                 int x, y;
3517
3518                                 Argument a = (Argument) args [j];
3519
3520                                 Type ct = candidate_pd.ParameterType (j);
3521                                 Type bt = best_pd.ParameterType (j);
3522
3523                                 if (candidate_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3524                                         if (expanded_form)
3525                                                 ct = ct.GetElementType ();
3526
3527                                 if (best_pd.ParameterModifier (j) == Parameter.Modifier.PARAMS)
3528                                         if (expanded_form)
3529                                                 bt = bt.GetElementType ();
3530
3531                                 x = BetterConversion (ec, a, ct, bt, loc);
3532                                 y = BetterConversion (ec, a, bt, ct, loc);
3533
3534                                 if (x < y)
3535                                         return 0;
3536
3537                                 rating1 += x;
3538                                 rating2 += y;
3539                         }
3540
3541                         if (rating1 > rating2)
3542                                 return 1;
3543                         else
3544                                 return 0;
3545                 }
3546
3547                 public static string FullMethodDesc (MethodBase mb)
3548                 {
3549                         string ret_type = "";
3550
3551                         if (mb is MethodInfo)
3552                                 ret_type = TypeManager.CSharpName (((MethodInfo) mb).ReturnType) + " ";
3553
3554                         StringBuilder sb = new StringBuilder (ret_type + mb.Name);
3555                         ParameterData pd = GetParameterData (mb);
3556
3557                         int count = pd.Count;
3558                         sb.Append (" (");
3559
3560                         for (int i = count; i > 0; ) {
3561                                 i--;
3562
3563                                 sb.Append (pd.ParameterDesc (count - i - 1));
3564                                 if (i != 0)
3565                                         sb.Append (", ");
3566                         }
3567
3568                         sb.Append (")");
3569                         return sb.ToString ();
3570                 }
3571
3572                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3573                 {
3574                         MemberInfo [] miset;
3575                         MethodGroupExpr union;
3576
3577                         if (mg1 == null){
3578                                 if (mg2 == null)
3579                                         return null;
3580                                 return (MethodGroupExpr) mg2;
3581                         } else {
3582                                 if (mg2 == null)
3583                                         return (MethodGroupExpr) mg1;
3584                         }
3585
3586                         MethodGroupExpr left_set = null, right_set = null;
3587                         int length1 = 0, length2 = 0;
3588
3589                         left_set = (MethodGroupExpr) mg1;
3590                         length1 = left_set.Methods.Length;
3591
3592                         right_set = (MethodGroupExpr) mg2;
3593                         length2 = right_set.Methods.Length;
3594
3595                         ArrayList common = new ArrayList ();
3596
3597                         foreach (MethodBase l in left_set.Methods){
3598                                 foreach (MethodBase r in right_set.Methods){
3599                                         if (l != r)
3600                                                 continue;
3601                                         common.Add (r);
3602                                         break;
3603                                 }
3604                         }
3605
3606                         miset = new MemberInfo [length1 + length2 - common.Count];
3607                         left_set.Methods.CopyTo (miset, 0);
3608
3609                         int k = length1;
3610
3611                         foreach (MemberInfo mi in right_set.Methods){
3612                                 if (!common.Contains (mi))
3613                                         miset [k++] = mi;
3614                         }
3615
3616                         union = new MethodGroupExpr (miset, loc);
3617
3618                         return union;
3619                 }
3620
3621                 /// <summary>
3622                 ///  Determines is the candidate method, if a params method, is applicable
3623                 ///  in its expanded form to the given set of arguments
3624                 /// </summary>
3625                 static bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments, MethodBase candidate)
3626                 {
3627                         int arg_count;
3628
3629                         if (arguments == null)
3630                                 arg_count = 0;
3631                         else
3632                                 arg_count = arguments.Count;
3633
3634                         ParameterData pd = GetParameterData (candidate);
3635
3636                         int pd_count = pd.Count;
3637
3638                         if (pd_count == 0)
3639                                 return false;
3640
3641                         if (pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS)
3642                                 return false;
3643
3644                         if (pd_count - 1 > arg_count)
3645                                 return false;
3646
3647                         if (pd_count == 1 && arg_count == 0)
3648                                 return true;
3649
3650                         //
3651                         // If we have come this far, the case which remains is when the number of parameters
3652                         // is less than or equal to the argument count.
3653                         //
3654                         for (int i = 0; i < pd_count - 1; ++i) {
3655
3656                                 Argument a = (Argument) arguments [i];
3657
3658                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3659                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3660                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3661                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3662
3663                                 if (a_mod == p_mod) {
3664
3665                                         if (a_mod == Parameter.Modifier.NONE)
3666                                                 if (!ImplicitConversionExists (ec, a.Expr, pd.ParameterType (i)))
3667                                                         return false;
3668
3669                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3670                                                 Type pt = pd.ParameterType (i);
3671
3672                                                 if (!pt.IsByRef)
3673                                                         pt = TypeManager.LookupType (pt.FullName + "&");
3674
3675                                                 if (pt != a.Type)
3676                                                         return false;
3677                                         }
3678                                 } else
3679                                         return false;
3680
3681                         }
3682
3683                         Type element_type = pd.ParameterType (pd_count - 1).GetElementType ();
3684
3685                         for (int i = pd_count - 1; i < arg_count; i++) {
3686                                 Argument a = (Argument) arguments [i];
3687
3688                                 if (!StandardConversionExists (a.Expr, element_type))
3689                                         return false;
3690                         }
3691
3692                         return true;
3693                 }
3694
3695                 /// <summary>
3696                 ///  Determines if the candidate method is applicable (section 14.4.2.1)
3697                 ///  to the given set of arguments
3698                 /// </summary>
3699                 static bool IsApplicable (EmitContext ec, ArrayList arguments, MethodBase candidate)
3700                 {
3701                         int arg_count;
3702
3703                         if (arguments == null)
3704                                 arg_count = 0;
3705                         else
3706                                 arg_count = arguments.Count;
3707
3708                         ParameterData pd = GetParameterData (candidate);
3709
3710                         int pd_count = pd.Count;
3711
3712                         if (arg_count != pd.Count)
3713                                 return false;
3714
3715                         for (int i = arg_count; i > 0; ) {
3716                                 i--;
3717
3718                                 Argument a = (Argument) arguments [i];
3719
3720                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3721                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3722                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3723                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3724
3725                                 if (a_mod == p_mod ||
3726                                     (a_mod == Parameter.Modifier.NONE && p_mod == Parameter.Modifier.PARAMS)) {
3727                                         if (a_mod == Parameter.Modifier.NONE)
3728                                                 if (!ImplicitConversionExists (ec, a.Expr, pd.ParameterType (i)))
3729                                                         return false;
3730
3731                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3732                                                 Type pt = pd.ParameterType (i);
3733
3734                                                 if (!pt.IsByRef)
3735                                                         pt = TypeManager.LookupType (pt.FullName + "&");
3736
3737                                                 if (pt != a.Type)
3738                                                         return false;
3739                                         }
3740                                 } else
3741                                         return false;
3742                         }
3743
3744                         return true;
3745                 }
3746
3747
3748
3749                 /// <summary>
3750                 ///   Find the Applicable Function Members (7.4.2.1)
3751                 ///
3752                 ///   me: Method Group expression with the members to select.
3753                 ///       it might contain constructors or methods (or anything
3754                 ///       that maps to a method).
3755                 ///
3756                 ///   Arguments: ArrayList containing resolved Argument objects.
3757                 ///
3758                 ///   loc: The location if we want an error to be reported, or a Null
3759                 ///        location for "probing" purposes.
3760                 ///
3761                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3762                 ///            that is the best match of me on Arguments.
3763                 ///
3764                 /// </summary>
3765                 public static MethodBase OverloadResolve (EmitContext ec, MethodGroupExpr me,
3766                                                           ArrayList Arguments, Location loc)
3767                 {
3768                         ArrayList afm = new ArrayList ();
3769                         MethodBase method = null;
3770                         Type current_type = null;
3771                         int argument_count;
3772                         ArrayList candidates = new ArrayList ();
3773
3774
3775                         foreach (MethodBase candidate in me.Methods){
3776                                 int x;
3777
3778                                 // If we're going one level higher in the class hierarchy, abort if
3779                                 // we already found an applicable method.
3780                                 if (candidate.DeclaringType != current_type) {
3781                                         current_type = candidate.DeclaringType;
3782                                         if (method != null)
3783                                                 break;
3784                                 }
3785
3786                                 // Check if candidate is applicable (section 14.4.2.1)
3787                                 if (!IsApplicable (ec, Arguments, candidate))
3788                                         continue;
3789
3790                                 candidates.Add (candidate);
3791                                 x = BetterFunction (ec, Arguments, candidate, method, false, loc);
3792
3793                                 if (x == 0)
3794                                         continue;
3795
3796                                 method = candidate;
3797                         }
3798
3799                         if (Arguments == null)
3800                                 argument_count = 0;
3801                         else
3802                                 argument_count = Arguments.Count;
3803
3804                         //
3805                         // Now we see if we can find params functions, applicable in their expanded form
3806                         // since if they were applicable in their normal form, they would have been selected
3807                         // above anyways
3808                         //
3809                         bool chose_params_expanded = false;
3810
3811                         if (method == null) {
3812                                 candidates = new ArrayList ();
3813                                 foreach (MethodBase candidate in me.Methods){
3814                                         if (!IsParamsMethodApplicable (ec, Arguments, candidate))
3815                                                 continue;
3816
3817                                         candidates.Add (candidate);
3818
3819                                         int x = BetterFunction (ec, Arguments, candidate, method, true, loc);
3820                                         if (x == 0)
3821                                                 continue;
3822
3823                                         method = candidate;
3824                                         chose_params_expanded = true;
3825                                 }
3826                         }
3827
3828                         if (method == null) {
3829                                 //
3830                                 // Okay so we have failed to find anything so we
3831                                 // return by providing info about the closest match
3832                                 //
3833                                 for (int i = 0; i < me.Methods.Length; ++i) {
3834
3835                                         MethodBase c = (MethodBase) me.Methods [i];
3836                                         ParameterData pd = GetParameterData (c);
3837
3838                                         if (pd.Count != argument_count)
3839                                                 continue;
3840
3841                                         VerifyArgumentsCompat (ec, Arguments, argument_count, c, false,
3842                                                                null, loc);
3843                                 }
3844
3845                                 return null;
3846                         }
3847
3848                         //
3849                         // Now check that there are no ambiguities i.e the selected method
3850                         // should be better than all the others
3851                         //
3852
3853                         foreach (MethodBase candidate in candidates){
3854                                 if (candidate == method)
3855                                         continue;
3856
3857                                 //
3858                                 // If a normal method is applicable in the sense that it has the same
3859                                 // number of arguments, then the expanded params method is never applicable
3860                                 // so we debar the params method.
3861                                 //
3862                                 if (IsParamsMethodApplicable (ec, Arguments, candidate) &&
3863                                     IsApplicable (ec, Arguments, method))
3864                                         continue;
3865
3866                                 int x = BetterFunction (ec, Arguments, method, candidate,
3867                                                         chose_params_expanded, loc);
3868
3869                                 if (x != 1) {
3870                                         Report.Error (
3871                                                 121, loc,
3872                                                 "Ambiguous call when selecting function due to implicit casts");
3873                                         return null;
3874                                 }
3875                         }
3876
3877                         //
3878                         // And now check if the arguments are all compatible, perform conversions
3879                         // if necessary etc. and return if everything is all right
3880                         //
3881
3882                         if (VerifyArgumentsCompat (ec, Arguments, argument_count, method,
3883                                                    chose_params_expanded, null, loc))
3884                                 return method;
3885                         else
3886                                 return null;
3887                 }
3888
3889                 public static bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
3890                                                           int argument_count,
3891                                                           MethodBase method,
3892                                                           bool chose_params_expanded,
3893                                                           Type delegate_type,
3894                                                           Location loc)
3895                 {
3896                         ParameterData pd = GetParameterData (method);
3897                         int pd_count = pd.Count;
3898
3899                         for (int j = 0; j < argument_count; j++) {
3900                                 Argument a = (Argument) Arguments [j];
3901                                 Expression a_expr = a.Expr;
3902                                 Type parameter_type = pd.ParameterType (j);
3903
3904                                 if (pd.ParameterModifier (j) == Parameter.Modifier.PARAMS &&
3905                                     chose_params_expanded)
3906                                         parameter_type = TypeManager.TypeToCoreType (parameter_type.GetElementType ());
3907
3908                                 if (a.Type != parameter_type){
3909                                         Expression conv;
3910
3911                                         conv = ConvertImplicit (ec, a_expr, parameter_type, loc);
3912
3913                                         if (conv == null) {
3914                                                 if (!Location.IsNull (loc)) {
3915                                                         if (delegate_type == null)
3916                                                                 Report.Error (1502, loc,
3917                                                                        "The best overloaded match for method '" +
3918                                                                        FullMethodDesc (method) +
3919                                                                        "' has some invalid arguments");
3920                                                         else
3921                                                                 Report.Error (1594, loc,
3922                                                                               "Delegate '" + delegate_type.ToString () +
3923                                                                               "' has some invalid arguments.");
3924                                                         Report.Error (1503, loc,
3925                                                          "Argument " + (j+1) +
3926                                                          ": Cannot convert from '" + Argument.FullDesc (a)
3927                                                          + "' to '" + pd.ParameterDesc (j) + "'");
3928                                                 }
3929
3930                                                 return false;
3931                                         }
3932
3933                                         //
3934                                         // Update the argument with the implicit conversion
3935                                         //
3936                                         if (a_expr != conv)
3937                                                 a.Expr = conv;
3938                                 }
3939
3940                                 Parameter.Modifier a_mod = a.GetParameterModifier () &
3941                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3942                                 Parameter.Modifier p_mod = pd.ParameterModifier (j) &
3943                                         ~(Parameter.Modifier.OUT | Parameter.Modifier.REF);
3944
3945
3946                                 if (a_mod != p_mod &&
3947                                     pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS) {
3948                                         if (!Location.IsNull (loc)) {
3949                                                 Console.WriteLine ("A:P: " + a.GetParameterModifier ());
3950                                                 Console.WriteLine ("PP:: " + pd.ParameterModifier (j));
3951                                                 Console.WriteLine ("PT:  " + parameter_type.IsByRef);
3952                                                 Report.Error (1502, loc,
3953                                                        "The best overloaded match for method '" + FullMethodDesc (method)+
3954                                                        "' has some invalid arguments");
3955                                                 Report.Error (1503, loc,
3956                                                        "Argument " + (j+1) +
3957                                                        ": Cannot convert from '" + Argument.FullDesc (a)
3958                                                        + "' to '" + pd.ParameterDesc (j) + "'");
3959                                         }
3960
3961                                         return false;
3962                                 }
3963                         }
3964
3965                         return true;
3966                 }
3967
3968                 public override Expression DoResolve (EmitContext ec)
3969                 {
3970                         //
3971                         // First, resolve the expression that is used to
3972                         // trigger the invocation
3973                         //
3974                         if (expr is BaseAccess)
3975                                 is_base = true;
3976
3977                         expr = expr.Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
3978                         if (expr == null)
3979                                 return null;
3980
3981                         if (!(expr is MethodGroupExpr)) {
3982                                 Type expr_type = expr.Type;
3983
3984                                 if (expr_type != null){
3985                                         bool IsDelegate = TypeManager.IsDelegateType (expr_type);
3986                                         if (IsDelegate)
3987                                                 return (new DelegateInvocation (
3988                                                         this.expr, Arguments, loc)).Resolve (ec);
3989                                 }
3990                         }
3991
3992                         if (!(expr is MethodGroupExpr)){
3993                                 expr.Error118 (ResolveFlags.MethodGroup);
3994                                 return null;
3995                         }
3996
3997                         //
3998                         // Next, evaluate all the expressions in the argument list
3999                         //
4000                         if (Arguments != null){
4001                                 foreach (Argument a in Arguments){
4002                                         if (!a.Resolve (ec, loc))
4003                                                 return null;
4004                                 }
4005                         }
4006
4007                         MethodGroupExpr mg = (MethodGroupExpr) expr;
4008                         method = OverloadResolve (ec, mg, Arguments, loc);
4009
4010                         if (method == null){
4011                                 Error (-6,
4012                                        "Could not find any applicable function for this argument list");
4013                                 return null;
4014                         }
4015
4016                         MethodInfo mi = method as MethodInfo;
4017                         if (mi != null) {
4018                                 type = TypeManager.TypeToCoreType (mi.ReturnType);
4019                                 if (!mi.IsStatic && !mg.IsExplicitImpl && (mg.InstanceExpression == null))
4020                                         SimpleName.Error_ObjectRefRequired (ec, loc, mi.Name);
4021                         }
4022
4023                         if (type.IsPointer){
4024                                 if (!ec.InUnsafe){
4025                                         UnsafeError (loc);
4026                                         return null;
4027                                 }
4028                         }
4029
4030                         eclass = ExprClass.Value;
4031                         return this;
4032                 }
4033
4034                 // <summary>
4035                 //   Emits the list of arguments as an array
4036                 // </summary>
4037                 static void EmitParams (EmitContext ec, int idx, ArrayList arguments)
4038                 {
4039                         ILGenerator ig = ec.ig;
4040                         int count = arguments.Count - idx;
4041                         Argument a = (Argument) arguments [idx];
4042                         Type t = a.Expr.Type;
4043                         string array_type = t.FullName + "[]";
4044                         LocalBuilder array;
4045
4046                         array = ig.DeclareLocal (TypeManager.LookupType (array_type));
4047                         IntConstant.EmitInt (ig, count);
4048                         ig.Emit (OpCodes.Newarr, TypeManager.TypeToCoreType (t));
4049                         ig.Emit (OpCodes.Stloc, array);
4050
4051                         int top = arguments.Count;
4052                         for (int j = idx; j < top; j++){
4053                                 a = (Argument) arguments [j];
4054
4055                                 ig.Emit (OpCodes.Ldloc, array);
4056                                 IntConstant.EmitInt (ig, j - idx);
4057                                 a.Emit (ec);
4058
4059                                 ArrayAccess.EmitStoreOpcode (ig, t);
4060                         }
4061                         ig.Emit (OpCodes.Ldloc, array);
4062                 }
4063
4064                 /// <summary>
4065                 ///   Emits a list of resolved Arguments that are in the arguments
4066                 ///   ArrayList.
4067                 ///
4068                 ///   The MethodBase argument might be null if the
4069                 ///   emission of the arguments is known not to contain
4070                 ///   a `params' field (for example in constructors or other routines
4071                 ///   that keep their arguments in this structure)
4072                 /// </summary>
4073                 public static void EmitArguments (EmitContext ec, MethodBase mb, ArrayList arguments)
4074                 {
4075                         ParameterData pd;
4076                         if (mb != null)
4077                                 pd = GetParameterData (mb);
4078                         else
4079                                 pd = null;
4080
4081                         //
4082                         // If we are calling a params method with no arguments, special case it
4083                         //
4084                         if (arguments == null){
4085                                 if (pd != null && pd.Count > 0 &&
4086                                     pd.ParameterModifier (0) == Parameter.Modifier.PARAMS){
4087                                         ILGenerator ig = ec.ig;
4088
4089                                         IntConstant.EmitInt (ig, 0);
4090                                         ig.Emit (OpCodes.Newarr, pd.ParameterType (0).GetElementType ());
4091                                 }
4092
4093                                 return;
4094                         }
4095
4096                         int top = arguments.Count;
4097
4098                         for (int i = 0; i < top; i++){
4099                                 Argument a = (Argument) arguments [i];
4100
4101                                 if (pd != null){
4102                                         if (pd.ParameterModifier (i) == Parameter.Modifier.PARAMS){
4103                                                 //
4104                                                 // Special case if we are passing the same data as the
4105                                                 // params argument, do not put it in an array.
4106                                                 //
4107                                                 if (pd.ParameterType (i) == a.Type)
4108                                                         a.Emit (ec);
4109                                                 else
4110                                                         EmitParams (ec, i, arguments);
4111                                                 return;
4112                                         }
4113                                 }
4114
4115                                 a.Emit (ec);
4116                         }
4117
4118                         if (pd != null && pd.Count > top &&
4119                             pd.ParameterModifier (top) == Parameter.Modifier.PARAMS){
4120                                 ILGenerator ig = ec.ig;
4121
4122                                 IntConstant.EmitInt (ig, 0);
4123                                 ig.Emit (OpCodes.Newarr, pd.ParameterType (top).GetElementType ());
4124                         }
4125                 }
4126
4127                 /// <remarks>
4128                 ///   is_base tells whether we want to force the use of the `call'
4129                 ///   opcode instead of using callvirt.  Call is required to call
4130                 ///   a specific method, while callvirt will always use the most
4131                 ///   recent method in the vtable.
4132                 ///
4133                 ///   is_static tells whether this is an invocation on a static method
4134                 ///
4135                 ///   instance_expr is an expression that represents the instance
4136                 ///   it must be non-null if is_static is false.
4137                 ///
4138                 ///   method is the method to invoke.
4139                 ///
4140                 ///   Arguments is the list of arguments to pass to the method or constructor.
4141                 /// </remarks>
4142                 public static void EmitCall (EmitContext ec, bool is_base,
4143                                              bool is_static, Expression instance_expr,
4144                                              MethodBase method, ArrayList Arguments, Location loc)
4145                 {
4146                         ILGenerator ig = ec.ig;
4147                         bool struct_call = false;
4148
4149                         Type decl_type = method.DeclaringType;
4150
4151                         if (!RootContext.StdLib) {
4152                                 // Replace any calls to the system's System.Array type with calls to
4153                                 // the newly created one.
4154                                 if (method == TypeManager.system_int_array_get_length)
4155                                         method = TypeManager.int_array_get_length;
4156                                 else if (method == TypeManager.system_int_array_get_rank)
4157                                         method = TypeManager.int_array_get_rank;
4158                                 else if (method == TypeManager.system_object_array_clone)
4159                                         method = TypeManager.object_array_clone;
4160                                 else if (method == TypeManager.system_int_array_get_length_int)
4161                                         method = TypeManager.int_array_get_length_int;
4162                                 else if (method == TypeManager.system_int_array_get_lower_bound_int)
4163                                         method = TypeManager.int_array_get_lower_bound_int;
4164                                 else if (method == TypeManager.system_int_array_get_upper_bound_int)
4165                                         method = TypeManager.int_array_get_upper_bound_int;
4166                                 else if (method == TypeManager.system_void_array_copyto_array_int)
4167                                         method = TypeManager.void_array_copyto_array_int;
4168                         }
4169
4170                         //
4171                         // This checks the `ConditionalAttribute' on the method, and the
4172                         // ObsoleteAttribute
4173                         //
4174                         TypeManager.MethodFlags flags = TypeManager.GetMethodFlags (method, loc);
4175                         if ((flags & TypeManager.MethodFlags.IsObsoleteError) != 0)
4176                                 return;
4177                         if ((flags & TypeManager.MethodFlags.ShouldIgnore) != 0)
4178                                 return;
4179
4180                         if (!is_static){
4181                                 if (decl_type.IsValueType)
4182                                         struct_call = true;
4183                                 //
4184                                 // If this is ourselves, push "this"
4185                                 //
4186                                 if (instance_expr == null){
4187                                         ig.Emit (OpCodes.Ldarg_0);
4188                                 } else {
4189                                         //
4190                                         // Push the instance expression
4191                                         //
4192                                         if (instance_expr.Type.IsValueType){
4193                                                 //
4194                                                 // Special case: calls to a function declared in a
4195                                                 // reference-type with a value-type argument need
4196                                                 // to have their value boxed.
4197
4198                                                 struct_call = true;
4199                                                 if (decl_type.IsValueType){
4200                                                         //
4201                                                         // If the expression implements IMemoryLocation, then
4202                                                         // we can optimize and use AddressOf on the
4203                                                         // return.
4204                                                         //
4205                                                         // If not we have to use some temporary storage for
4206                                                         // it.
4207                                                         if (instance_expr is IMemoryLocation){
4208                                                                 ((IMemoryLocation)instance_expr).
4209                                                                         AddressOf (ec, AddressOp.LoadStore);
4210                                                         }
4211                                                         else {
4212                                                                 Type t = instance_expr.Type;
4213
4214                                                                 instance_expr.Emit (ec);
4215                                                                 LocalBuilder temp = ig.DeclareLocal (t);
4216                                                                 ig.Emit (OpCodes.Stloc, temp);
4217                                                                 ig.Emit (OpCodes.Ldloca, temp);
4218                                                         }
4219                                                 } else {
4220                                                         instance_expr.Emit (ec);
4221                                                         ig.Emit (OpCodes.Box, instance_expr.Type);
4222                                                 }
4223                                         } else
4224                                                 instance_expr.Emit (ec);
4225                                 }
4226                         }
4227
4228                         EmitArguments (ec, method, Arguments);
4229
4230                         if (is_static || struct_call || is_base){
4231                                 if (method is MethodInfo) {
4232                                         ig.Emit (OpCodes.Call, (MethodInfo) method);
4233                                 } else
4234                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4235                         } else {
4236                                 if (method is MethodInfo)
4237                                         ig.Emit (OpCodes.Callvirt, (MethodInfo) method);
4238                                 else
4239                                         ig.Emit (OpCodes.Callvirt, (ConstructorInfo) method);
4240                         }
4241                 }
4242
4243                 public override void Emit (EmitContext ec)
4244                 {
4245                         MethodGroupExpr mg = (MethodGroupExpr) this.expr;
4246
4247                         EmitCall (
4248                                 ec, is_base, method.IsStatic, mg.InstanceExpression, method, Arguments, loc);
4249                 }
4250
4251                 public override void EmitStatement (EmitContext ec)
4252                 {
4253                         Emit (ec);
4254
4255                         //
4256                         // Pop the return value if there is one
4257                         //
4258                         if (method is MethodInfo){
4259                                 Type ret = ((MethodInfo)method).ReturnType;
4260                                 if (TypeManager.TypeToCoreType (ret) != TypeManager.void_type)
4261                                         ec.ig.Emit (OpCodes.Pop);
4262                         }
4263                 }
4264         }
4265
4266         //
4267         // This class is used to "disable" the code generation for the
4268         // temporary variable when initializing value types.
4269         //
4270         class EmptyAddressOf : EmptyExpression, IMemoryLocation {
4271                 public void AddressOf (EmitContext ec, AddressOp Mode)
4272                 {
4273                         // nothing
4274                 }
4275         }
4276
4277         /// <summary>
4278         ///    Implements the new expression
4279         /// </summary>
4280         public class New : ExpressionStatement {
4281                 public readonly ArrayList Arguments;
4282                 public readonly Expression RequestedType;
4283
4284                 MethodBase method = null;
4285
4286                 //
4287                 // If set, the new expression is for a value_target, and
4288                 // we will not leave anything on the stack.
4289                 //
4290                 Expression value_target;
4291                 bool value_target_set = false;
4292
4293                 public New (Expression requested_type, ArrayList arguments, Location l)
4294                 {
4295                         RequestedType = requested_type;
4296                         Arguments = arguments;
4297                         loc = l;
4298                 }
4299
4300                 public Expression ValueTypeVariable {
4301                         get {
4302                                 return value_target;
4303                         }
4304
4305                         set {
4306                                 value_target = value;
4307                                 value_target_set = true;
4308                         }
4309                 }
4310
4311                 //
4312                 // This function is used to disable the following code sequence for
4313                 // value type initialization:
4314                 //
4315                 // AddressOf (temporary)
4316                 // Construct/Init
4317                 // LoadTemporary
4318                 //
4319                 // Instead the provide will have provided us with the address on the
4320                 // stack to store the results.
4321                 //
4322                 static Expression MyEmptyExpression;
4323
4324                 public void DisableTemporaryValueType ()
4325                 {
4326                         if (MyEmptyExpression == null)
4327                                 MyEmptyExpression = new EmptyAddressOf ();
4328
4329                         //
4330                         // To enable this, look into:
4331                         // test-34 and test-89 and self bootstrapping.
4332                         //
4333                         // For instance, we can avoid a copy by using `newobj'
4334                         // instead of Call + Push-temp on value types.
4335 //                      value_target = MyEmptyExpression;
4336                 }
4337
4338                 public override Expression DoResolve (EmitContext ec)
4339                 {
4340                         type = ec.DeclSpace.ResolveType (RequestedType, false, loc);
4341
4342                         if (type == null)
4343                                 return null;
4344
4345                         bool IsDelegate = TypeManager.IsDelegateType (type);
4346
4347                         if (IsDelegate)
4348                                 return (new NewDelegate (type, Arguments, loc)).Resolve (ec);
4349
4350                         if (type.IsInterface || type.IsAbstract){
4351                                 Error (
4352                                         144, "It is not possible to create instances of interfaces " +
4353                                         "or abstract classes");
4354                                 return null;
4355                         }
4356
4357                         bool is_struct = false;
4358                         is_struct = type.IsValueType;
4359                         eclass = ExprClass.Value;
4360
4361                         //
4362                         // SRE returns a match for .ctor () on structs (the object constructor),
4363                         // so we have to manually ignore it.
4364                         //
4365                         if (is_struct && Arguments == null)
4366                                 return this;
4367
4368                         Expression ml;
4369                         ml = MemberLookupFinal (ec, type, ".ctor",
4370                                                 MemberTypes.Constructor,
4371                                                 AllBindingFlags | BindingFlags.DeclaredOnly, loc);
4372
4373                         if (ml == null)
4374                                 return null;
4375
4376                         if (! (ml is MethodGroupExpr)){
4377                                 if (!is_struct){
4378                                         ml.Error118 ("method group");
4379                                         return null;
4380                                 }
4381                         }
4382
4383                         if (ml != null) {
4384                                 if (Arguments != null){
4385                                         foreach (Argument a in Arguments){
4386                                                 if (!a.Resolve (ec, loc))
4387                                                         return null;
4388                                         }
4389                                 }
4390
4391                                 method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml,
4392                                                                      Arguments, loc);
4393
4394                         }
4395
4396                         if (method == null) {
4397                                 if (!is_struct || Arguments.Count > 0) {
4398                                         Error (1501,
4399                                                "New invocation: Can not find a constructor for " +
4400                                                "this argument list");
4401                                         return null;
4402                                 }
4403                         }
4404                         return this;
4405                 }
4406
4407                 //
4408                 // This DoEmit can be invoked in two contexts:
4409                 //    * As a mechanism that will leave a value on the stack (new object)
4410                 //    * As one that wont (init struct)
4411                 //
4412                 // You can control whether a value is required on the stack by passing
4413                 // need_value_on_stack.  The code *might* leave a value on the stack
4414                 // so it must be popped manually
4415                 //
4416                 // If we are dealing with a ValueType, we have a few
4417                 // situations to deal with:
4418                 //
4419                 //    * The target is a ValueType, and we have been provided
4420                 //      the instance (this is easy, we are being assigned).
4421                 //
4422                 //    * The target of New is being passed as an argument,
4423                 //      to a boxing operation or a function that takes a
4424                 //      ValueType.
4425                 //
4426                 //      In this case, we need to create a temporary variable
4427                 //      that is the argument of New.
4428                 //
4429                 // Returns whether a value is left on the stack
4430                 //
4431                 bool DoEmit (EmitContext ec, bool need_value_on_stack)
4432                 {
4433                         bool is_value_type = type.IsValueType;
4434                         ILGenerator ig = ec.ig;
4435
4436                         if (is_value_type){
4437                                 IMemoryLocation ml;
4438
4439                                 // Allow DoEmit() to be called multiple times.
4440                                 // We need to create a new LocalTemporary each time since
4441                                 // you can't share LocalBuilders among ILGeneators.
4442                                 if (!value_target_set)
4443                                         value_target = new LocalTemporary (ec, type);
4444
4445                                 ml = (IMemoryLocation) value_target;
4446                                 ml.AddressOf (ec, AddressOp.Store);
4447                         }
4448
4449                         if (method != null)
4450                                 Invocation.EmitArguments (ec, method, Arguments);
4451
4452                         if (is_value_type){
4453                                 if (method == null)
4454                                         ig.Emit (OpCodes.Initobj, type);
4455                                 else
4456                                         ig.Emit (OpCodes.Call, (ConstructorInfo) method);
4457                                 if (need_value_on_stack){
4458                                         value_target.Emit (ec);
4459                                         return true;
4460                                 }
4461                                 return false;
4462                         } else {
4463                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) method);
4464                                 return true;
4465                         }
4466                 }
4467
4468                 public override void Emit (EmitContext ec)
4469                 {
4470                         DoEmit (ec, true);
4471                 }
4472
4473                 public override void EmitStatement (EmitContext ec)
4474                 {
4475                         if (DoEmit (ec, false))
4476                                 ec.ig.Emit (OpCodes.Pop);
4477                 }
4478         }
4479
4480         /// <summary>
4481         ///   14.5.10.2: Represents an array creation expression.
4482         /// </summary>
4483         ///
4484         /// <remarks>
4485         ///   There are two possible scenarios here: one is an array creation
4486         ///   expression that specifies the dimensions and optionally the
4487         ///   initialization data and the other which does not need dimensions
4488         ///   specified but where initialization data is mandatory.
4489         /// </remarks>
4490         public class ArrayCreation : ExpressionStatement {
4491                 Expression requested_base_type;
4492                 ArrayList initializers;
4493
4494                 //
4495                 // The list of Argument types.
4496                 // This is used to construct the `newarray' or constructor signature
4497                 //
4498                 ArrayList arguments;
4499
4500                 //
4501                 // Method used to create the array object.
4502                 //
4503                 MethodBase new_method = null;
4504
4505                 Type array_element_type;
4506                 Type underlying_type;
4507                 bool is_one_dimensional = false;
4508                 bool is_builtin_type = false;
4509                 bool expect_initializers = false;
4510                 int num_arguments = 0;
4511                 int dimensions = 0;
4512                 string rank;
4513
4514                 ArrayList array_data;
4515
4516                 Hashtable bounds;
4517
4518                 //
4519                 // The number of array initializers that we can handle
4520                 // via the InitializeArray method - through EmitStaticInitializers
4521                 //
4522                 int num_automatic_initializers;
4523
4524                 public ArrayCreation (Expression requested_base_type, ArrayList exprs, string rank, ArrayList initializers, Location l)
4525                 {
4526                         this.requested_base_type = requested_base_type;
4527                         this.initializers = initializers;
4528                         this.rank = rank;
4529                         loc = l;
4530
4531                         arguments = new ArrayList ();
4532
4533                         foreach (Expression e in exprs) {
4534                                 arguments.Add (new Argument (e, Argument.AType.Expression));
4535                                 num_arguments++;
4536                         }
4537                 }
4538
4539                 public ArrayCreation (Expression requested_base_type, string rank, ArrayList initializers, Location l)
4540                 {
4541                         this.requested_base_type = requested_base_type;
4542                         this.initializers = initializers;
4543                         this.rank = rank;
4544                         loc = l;
4545
4546                         //this.rank = rank.Substring (0, rank.LastIndexOf ("["));
4547                         //
4548                         //string tmp = rank.Substring (rank.LastIndexOf ("["));
4549                         //
4550                         //dimensions = tmp.Length - 1;
4551                         expect_initializers = true;
4552                 }
4553
4554                 public Expression FormArrayType (Expression base_type, int idx_count, string rank)
4555                 {
4556                         StringBuilder sb = new StringBuilder (rank);
4557
4558                         sb.Append ("[");
4559                         for (int i = 1; i < idx_count; i++)
4560                                 sb.Append (",");
4561
4562                         sb.Append ("]");
4563
4564                         return new ComposedCast (base_type, sb.ToString (), loc);
4565                 }
4566
4567                 void Error_IncorrectArrayInitializer ()
4568                 {
4569                         Error (178, "Incorrectly structured array initializer");
4570                 }
4571
4572                 public bool CheckIndices (EmitContext ec, ArrayList probe, int idx, bool specified_dims)
4573                 {
4574                         if (specified_dims) {
4575                                 Argument a = (Argument) arguments [idx];
4576
4577                                 if (!a.Resolve (ec, loc))
4578                                         return false;
4579
4580                                 if (!(a.Expr is Constant)) {
4581                                         Error (150, "A constant value is expected");
4582                                         return false;
4583                                 }
4584
4585                                 int value = (int) ((Constant) a.Expr).GetValue ();
4586
4587                                 if (value != probe.Count) {
4588                                         Error_IncorrectArrayInitializer ();
4589                                         return false;
4590                                 }
4591
4592                                 bounds [idx] = value;
4593                         }
4594
4595                         int child_bounds = -1;
4596                         foreach (object o in probe) {
4597                                 if (o is ArrayList) {
4598                                         int current_bounds = ((ArrayList) o).Count;
4599
4600                                         if (child_bounds == -1)
4601                                                 child_bounds = current_bounds;
4602
4603                                         else if (child_bounds != current_bounds){
4604                                                 Error_IncorrectArrayInitializer ();
4605                                                 return false;
4606                                         }
4607                                         bool ret = CheckIndices (ec, (ArrayList) o, idx + 1, specified_dims);
4608                                         if (!ret)
4609                                                 return false;
4610                                 } else {
4611                                         if (child_bounds != -1){
4612                                                 Error_IncorrectArrayInitializer ();
4613                                                 return false;
4614                                         }
4615
4616                                         Expression tmp = (Expression) o;
4617                                         tmp = tmp.Resolve (ec);
4618                                         if (tmp == null)
4619                                                 continue;
4620
4621                                         // Console.WriteLine ("I got: " + tmp);
4622                                         // Handle initialization from vars, fields etc.
4623
4624                                         Expression conv = ConvertImplicitRequired (
4625                                                 ec, tmp, underlying_type, loc);
4626
4627                                         if (conv == null)
4628                                                 return false;
4629
4630                                         if (conv is StringConstant)
4631                                                 array_data.Add (conv);
4632                                         else if (conv is Constant) {
4633                                                 array_data.Add (conv);
4634                                                 num_automatic_initializers++;
4635                                         } else
4636                                                 array_data.Add (conv);
4637                                 }
4638                         }
4639
4640                         return true;
4641                 }
4642
4643                 public void UpdateIndices (EmitContext ec)
4644                 {
4645                         int i = 0;
4646                         for (ArrayList probe = initializers; probe != null;) {
4647                                 if (probe.Count > 0 && probe [0] is ArrayList) {
4648                                         Expression e = new IntConstant (probe.Count);
4649                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4650
4651                                         bounds [i++] =  probe.Count;
4652
4653                                         probe = (ArrayList) probe [0];
4654
4655                                 } else {
4656                                         Expression e = new IntConstant (probe.Count);
4657                                         arguments.Add (new Argument (e, Argument.AType.Expression));
4658
4659                                         bounds [i++] = probe.Count;
4660                                         probe = null;
4661                                 }
4662                         }
4663
4664                 }
4665
4666                 public bool ValidateInitializers (EmitContext ec, Type array_type)
4667                 {
4668                         if (initializers == null) {
4669                                 if (expect_initializers)
4670                                         return false;
4671                                 else
4672                                         return true;
4673                         }
4674
4675                         if (underlying_type == null)
4676                                 return false;
4677
4678                         //
4679                         // We use this to store all the date values in the order in which we
4680                         // will need to store them in the byte blob later
4681                         //
4682                         array_data = new ArrayList ();
4683                         bounds = new Hashtable ();
4684
4685                         bool ret;
4686
4687                         if (arguments != null) {
4688                                 ret = CheckIndices (ec, initializers, 0, true);
4689                                 return ret;
4690                         } else {
4691                                 arguments = new ArrayList ();
4692
4693                                 ret = CheckIndices (ec, initializers, 0, false);
4694
4695                                 if (!ret)
4696                                         return false;
4697
4698                                 UpdateIndices (ec);
4699
4700                                 if (arguments.Count != dimensions) {
4701                                         Error_IncorrectArrayInitializer ();
4702                                         return false;
4703                                 }
4704
4705                                 return ret;
4706                         }
4707                 }
4708
4709                 void Error_NegativeArrayIndex ()
4710                 {
4711                         Error (284, "Can not create array with a negative size");
4712                 }
4713
4714                 //
4715                 // Converts `source' to an int, uint, long or ulong.
4716                 //
4717                 Expression ExpressionToArrayArgument (EmitContext ec, Expression source)
4718                 {
4719                         Expression target;
4720
4721                         bool old_checked = ec.CheckState;
4722                         ec.CheckState = true;
4723
4724                         target = ConvertImplicit (ec, source, TypeManager.int32_type, loc);
4725                         if (target == null){
4726                                 target = ConvertImplicit (ec, source, TypeManager.uint32_type, loc);
4727                                 if (target == null){
4728                                         target = ConvertImplicit (ec, source, TypeManager.int64_type, loc);
4729                                         if (target == null){
4730                                                 target = ConvertImplicit (ec, source, TypeManager.uint64_type, loc);
4731                                                 if (target == null)
4732                                                         Expression.Error_CannotConvertImplicit (loc, source.Type, TypeManager.int32_type);
4733                                         }
4734                                 }
4735                         }
4736                         ec.CheckState = old_checked;
4737
4738                         //
4739                         // Only positive constants are allowed at compile time
4740                         //
4741                         if (target is Constant){
4742                                 if (target is IntConstant){
4743                                         if (((IntConstant) target).Value < 0){
4744                                                 Error_NegativeArrayIndex ();
4745                                                 return null;
4746                                         }
4747                                 }
4748
4749                                 if (target is LongConstant){
4750                                         if (((LongConstant) target).Value < 0){
4751                                                 Error_NegativeArrayIndex ();
4752                                                 return null;
4753                                         }
4754                                 }
4755
4756                         }
4757
4758                         return target;
4759                 }
4760
4761                 //
4762                 // Creates the type of the array
4763                 //
4764                 bool LookupType (EmitContext ec)
4765                 {
4766                         StringBuilder array_qualifier = new StringBuilder (rank);
4767
4768                         //
4769                         // `In the first form allocates an array instace of the type that results
4770                         // from deleting each of the individual expression from the expression list'
4771                         //
4772                         if (num_arguments > 0) {
4773                                 array_qualifier.Append ("[");
4774                                 for (int i = num_arguments-1; i > 0; i--)
4775                                         array_qualifier.Append (",");
4776                                 array_qualifier.Append ("]");
4777                         }
4778
4779                         //
4780                         // Lookup the type
4781                         //
4782                         Expression array_type_expr;
4783                         array_type_expr = new ComposedCast (requested_base_type, array_qualifier.ToString (), loc);
4784                         type = ec.DeclSpace.ResolveType (array_type_expr, false, loc);
4785
4786                         if (type == null)
4787                                 return false;
4788
4789                         underlying_type = type;
4790                         if (underlying_type.IsArray)
4791                                 underlying_type = TypeManager.TypeToCoreType (underlying_type.GetElementType ());
4792                         dimensions = type.GetArrayRank ();
4793
4794                         return true;
4795                 }
4796
4797                 public override Expression DoResolve (EmitContext ec)
4798                 {
4799                         int arg_count;
4800
4801                         if (!LookupType (ec))
4802                                 return null;
4803
4804                         //
4805                         // First step is to validate the initializers and fill
4806                         // in any missing bits
4807                         //
4808                         if (!ValidateInitializers (ec, type))
4809                                 return null;
4810
4811                         if (arguments == null)
4812                                 arg_count = 0;
4813                         else {
4814                                 arg_count = arguments.Count;
4815                                 foreach (Argument a in arguments){
4816                                         if (!a.Resolve (ec, loc))
4817                                                 return null;
4818
4819                                         Expression real_arg = ExpressionToArrayArgument (ec, a.Expr, loc);
4820                                         if (real_arg == null)
4821                                                 return null;
4822
4823                                         a.Expr = real_arg;
4824                                 }
4825                         }
4826
4827                         array_element_type = TypeManager.TypeToCoreType (type.GetElementType ());
4828
4829                         if (arg_count == 1) {
4830                                 is_one_dimensional = true;
4831                                 eclass = ExprClass.Value;
4832                                 return this;
4833                         }
4834
4835                         is_builtin_type = TypeManager.IsBuiltinType (type);
4836
4837                         if (is_builtin_type) {
4838                                 Expression ml;
4839
4840                                 ml = MemberLookup (ec, type, ".ctor", MemberTypes.Constructor,
4841                                                    AllBindingFlags, loc);
4842
4843                                 if (!(ml is MethodGroupExpr)) {
4844                                         ml.Error118 ("method group");
4845                                         return null;
4846                                 }
4847
4848                                 if (ml == null) {
4849                                         Error (-6, "New invocation: Can not find a constructor for " +
4850                                                       "this argument list");
4851                                         return null;
4852                                 }
4853
4854                                 new_method = Invocation.OverloadResolve (ec, (MethodGroupExpr) ml, arguments, loc);
4855
4856                                 if (new_method == null) {
4857                                         Error (-6, "New invocation: Can not find a constructor for " +
4858                                                       "this argument list");
4859                                         return null;
4860                                 }
4861
4862                                 eclass = ExprClass.Value;
4863                                 return this;
4864                         } else {
4865                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
4866                                 ArrayList args = new ArrayList ();
4867
4868                                 if (arguments != null) {
4869                                         for (int i = 0; i < arg_count; i++)
4870                                                 args.Add (TypeManager.int32_type);
4871                                 }
4872
4873                                 Type [] arg_types = null;
4874
4875                                 if (args.Count > 0)
4876                                         arg_types = new Type [args.Count];
4877
4878                                 args.CopyTo (arg_types, 0);
4879
4880                                 new_method = mb.GetArrayMethod (type, ".ctor", CallingConventions.HasThis, null,
4881                                                             arg_types);
4882
4883                                 if (new_method == null) {
4884                                         Error (-6, "New invocation: Can not find a constructor for " +
4885                                                       "this argument list");
4886                                         return null;
4887                                 }
4888
4889                                 eclass = ExprClass.Value;
4890                                 return this;
4891                         }
4892                 }
4893
4894                 public static byte [] MakeByteBlob (ArrayList array_data, Type underlying_type, Location loc)
4895                 {
4896                         int factor;
4897                         byte [] data;
4898                         byte [] element;
4899                         int count = array_data.Count;
4900
4901                         if (underlying_type.IsEnum)
4902                                 underlying_type = TypeManager.EnumToUnderlying (underlying_type);
4903
4904                         factor = GetTypeSize (underlying_type);
4905                         if (factor == 0)
4906                                 throw new Exception ("unrecognized type in MakeByteBlob: " + underlying_type);
4907
4908                         data = new byte [(count * factor + 4) & ~3];
4909                         int idx = 0;
4910
4911                         for (int i = 0; i < count; ++i) {
4912                                 object v = array_data [i];
4913
4914                                 if (v is EnumConstant)
4915                                         v = ((EnumConstant) v).Child;
4916
4917                                 if (v is Constant && !(v is StringConstant))
4918                                         v = ((Constant) v).GetValue ();
4919                                 else {
4920                                         idx += factor;
4921                                         continue;
4922                                 }
4923
4924                                 if (underlying_type == TypeManager.int64_type){
4925                                         if (!(v is Expression)){
4926                                                 long val = (long) v;
4927
4928                                                 for (int j = 0; j < factor; ++j) {
4929                                                         data [idx + j] = (byte) (val & 0xFF);
4930                                                         val = (val >> 8);
4931                                                 }
4932                                         }
4933                                 } else if (underlying_type == TypeManager.uint64_type){
4934                                         if (!(v is Expression)){
4935                                                 ulong val = (ulong) v;
4936
4937                                                 for (int j = 0; j < factor; ++j) {
4938                                                         data [idx + j] = (byte) (val & 0xFF);
4939                                                         val = (val >> 8);
4940                                                 }
4941                                         }
4942                                 } else if (underlying_type == TypeManager.float_type) {
4943                                         if (!(v is Expression)){
4944                                                 element = BitConverter.GetBytes ((float) v);
4945
4946                                                 for (int j = 0; j < factor; ++j)
4947                                                         data [idx + j] = element [j];
4948                                         }
4949                                 } else if (underlying_type == TypeManager.double_type) {
4950                                         if (!(v is Expression)){
4951                                                 element = BitConverter.GetBytes ((double) v);
4952
4953                                                 for (int j = 0; j < factor; ++j)
4954                                                         data [idx + j] = element [j];
4955                                         }
4956                                 } else if (underlying_type == TypeManager.char_type){
4957                                         if (!(v is Expression)){
4958                                                 int val = (int) ((char) v);
4959
4960                                                 data [idx] = (byte) (val & 0xff);
4961                                                 data [idx+1] = (byte) (val >> 8);
4962                                         }
4963                                 } else if (underlying_type == TypeManager.short_type){
4964                                         if (!(v is Expression)){
4965                                                 int val = (int) ((short) v);
4966
4967                                                 data [idx] = (byte) (val & 0xff);
4968                                                 data [idx+1] = (byte) (val >> 8);
4969                                         }
4970                                 } else if (underlying_type == TypeManager.ushort_type){
4971                                         if (!(v is Expression)){
4972                                                 int val = (int) ((ushort) v);
4973
4974                                                 data [idx] = (byte) (val & 0xff);
4975                                                 data [idx+1] = (byte) (val >> 8);
4976                                         }
4977                                 } else if (underlying_type == TypeManager.int32_type) {
4978                                         if (!(v is Expression)){
4979                                                 int val = (int) v;
4980
4981                                                 data [idx]   = (byte) (val & 0xff);
4982                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
4983                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
4984                                                 data [idx+3] = (byte) (val >> 24);
4985                                         }
4986                                 } else if (underlying_type == TypeManager.uint32_type) {
4987                                         if (!(v is Expression)){
4988                                                 uint val = (uint) v;
4989
4990                                                 data [idx]   = (byte) (val & 0xff);
4991                                                 data [idx+1] = (byte) ((val >> 8) & 0xff);
4992                                                 data [idx+2] = (byte) ((val >> 16) & 0xff);
4993                                                 data [idx+3] = (byte) (val >> 24);
4994                                         }
4995                                 } else if (underlying_type == TypeManager.sbyte_type) {
4996                                         if (!(v is Expression)){
4997                                                 sbyte val = (sbyte) v;
4998                                                 data [idx] = (byte) val;
4999                                         }
5000                                 } else if (underlying_type == TypeManager.byte_type) {
5001                                         if (!(v is Expression)){
5002                                                 byte val = (byte) v;
5003                                                 data [idx] = (byte) val;
5004                                         }
5005                                 } else if (underlying_type == TypeManager.bool_type) {
5006                                         if (!(v is Expression)){
5007                                                 bool val = (bool) v;
5008                                                 data [idx] = (byte) (val ? 1 : 0);
5009                                         }
5010                                 } else if (underlying_type == TypeManager.decimal_type){
5011                                         if (!(v is Expression)){
5012                                                 int [] bits = Decimal.GetBits ((decimal) v);
5013                                                 int p = idx;
5014
5015                                                 for (int j = 0; j < 4; j++){
5016                                                         data [p++] = (byte) (bits [j] & 0xff);
5017                                                         data [p++] = (byte) ((bits [j] >> 8) & 0xff);
5018                                                         data [p++] = (byte) ((bits [j] >> 16) & 0xff);
5019                                                         data [p++] = (byte) (bits [j] >> 24);
5020                                                 }
5021                                         }
5022                                 } else
5023                                         throw new Exception ("Unrecognized type in MakeByteBlob: " + underlying_type);
5024
5025                                 idx += factor;
5026                         }
5027
5028                         return data;
5029                 }
5030
5031                 //
5032                 // Emits the initializers for the array
5033                 //
5034                 void EmitStaticInitializers (EmitContext ec, bool is_expression)
5035                 {
5036                         //
5037                         // First, the static data
5038                         //
5039                         FieldBuilder fb;
5040                         ILGenerator ig = ec.ig;
5041
5042                         byte [] data = MakeByteBlob (array_data, underlying_type, loc);
5043
5044                         fb = RootContext.MakeStaticData (data);
5045
5046                         if (is_expression)
5047                                 ig.Emit (OpCodes.Dup);
5048                         ig.Emit (OpCodes.Ldtoken, fb);
5049                         ig.Emit (OpCodes.Call,
5050                                  TypeManager.void_initializearray_array_fieldhandle);
5051                 }
5052
5053                 //
5054                 // Emits pieces of the array that can not be computed at compile
5055                 // time (variables and string locations).
5056                 //
5057                 // This always expect the top value on the stack to be the array
5058                 //
5059                 void EmitDynamicInitializers (EmitContext ec, bool is_expression)
5060                 {
5061                         ILGenerator ig = ec.ig;
5062                         int dims = bounds.Count;
5063                         int [] current_pos = new int [dims];
5064                         int top = array_data.Count;
5065                         LocalBuilder temp = ig.DeclareLocal (type);
5066
5067                         ig.Emit (OpCodes.Stloc, temp);
5068
5069                         MethodInfo set = null;
5070
5071                         if (dims != 1){
5072                                 Type [] args;
5073                                 ModuleBuilder mb = null;
5074                                 mb = CodeGen.ModuleBuilder;
5075                                 args = new Type [dims + 1];
5076
5077                                 int j;
5078                                 for (j = 0; j < dims; j++)
5079                                         args [j] = TypeManager.int32_type;
5080
5081                                 args [j] = array_element_type;
5082
5083                                 set = mb.GetArrayMethod (
5084                                         type, "Set",
5085                                         CallingConventions.HasThis | CallingConventions.Standard,
5086                                         TypeManager.void_type, args);
5087                         }
5088
5089                         for (int i = 0; i < top; i++){
5090
5091                                 Expression e = null;
5092
5093                                 if (array_data [i] is Expression)
5094                                         e = (Expression) array_data [i];
5095
5096                                 if (e != null) {
5097                                         //
5098                                         // Basically we do this for string literals and
5099                                         // other non-literal expressions
5100                                         //
5101                                         if (e is StringConstant || !(e is Constant) ||
5102                                             num_automatic_initializers <= 2) {
5103                                                 Type etype = e.Type;
5104
5105                                                 ig.Emit (OpCodes.Ldloc, temp);
5106
5107                                                 for (int idx = 0; idx < dims; idx++)
5108                                                         IntConstant.EmitInt (ig, current_pos [idx]);
5109
5110                                                 //
5111                                                 // If we are dealing with a struct, get the
5112                                                 // address of it, so we can store it.
5113                                                 //
5114                                                 if ((dims == 1) &&
5115                                                     etype.IsSubclassOf (TypeManager.value_type) &&
5116                                                     (!TypeManager.IsBuiltinType (etype) ||
5117                                                      etype == TypeManager.decimal_type)) {
5118                                                         if (e is New){
5119                                                                 New n = (New) e;
5120
5121                                                                 //
5122                                                                 // Let new know that we are providing
5123                                                                 // the address where to store the results
5124                                                                 //
5125                                                                 n.DisableTemporaryValueType ();
5126                                                         }
5127
5128                                                         ig.Emit (OpCodes.Ldelema, etype);
5129                                                 }
5130
5131                                                 e.Emit (ec);
5132
5133                                                 if (dims == 1)
5134                                                         ArrayAccess.EmitStoreOpcode (ig, array_element_type);
5135                                                 else
5136                                                         ig.Emit (OpCodes.Call, set);
5137                                         }
5138                                 }
5139
5140                                 //
5141                                 // Advance counter
5142                                 //
5143                                 for (int j = dims - 1; j >= 0; j--){
5144                                         current_pos [j]++;
5145                                         if (current_pos [j] < (int) bounds [j])
5146                                                 break;
5147                                         current_pos [j] = 0;
5148                                 }
5149                         }
5150
5151                         if (is_expression)
5152                                 ig.Emit (OpCodes.Ldloc, temp);
5153                 }
5154
5155                 void EmitArrayArguments (EmitContext ec)
5156                 {
5157                         ILGenerator ig = ec.ig;
5158
5159                         foreach (Argument a in arguments) {
5160                                 Type atype = a.Type;
5161                                 a.Emit (ec);
5162
5163                                 if (atype == TypeManager.uint64_type)
5164                                         ig.Emit (OpCodes.Conv_Ovf_U4);
5165                                 else if (atype == TypeManager.int64_type)
5166                                         ig.Emit (OpCodes.Conv_Ovf_I4);
5167                         }
5168                 }
5169
5170                 void DoEmit (EmitContext ec, bool is_statement)
5171                 {
5172                         ILGenerator ig = ec.ig;
5173
5174                         EmitArrayArguments (ec);
5175                         if (is_one_dimensional)
5176                                 ig.Emit (OpCodes.Newarr, array_element_type);
5177                         else {
5178                                 if (is_builtin_type)
5179                                         ig.Emit (OpCodes.Newobj, (ConstructorInfo) new_method);
5180                                 else
5181                                         ig.Emit (OpCodes.Newobj, (MethodInfo) new_method);
5182                         }
5183
5184                         if (initializers != null){
5185                                 //
5186                                 // FIXME: Set this variable correctly.
5187                                 //
5188                                 bool dynamic_initializers = true;
5189
5190                                 if (underlying_type != TypeManager.string_type &&
5191                                     underlying_type != TypeManager.object_type) {
5192                                         if (num_automatic_initializers > 2)
5193                                                 EmitStaticInitializers (ec, dynamic_initializers || !is_statement);
5194                                 }
5195
5196                                 if (dynamic_initializers)
5197                                         EmitDynamicInitializers (ec, !is_statement);
5198                         }
5199                 }
5200
5201                 public override void Emit (EmitContext ec)
5202                 {
5203                         DoEmit (ec, false);
5204                 }
5205
5206                 public override void EmitStatement (EmitContext ec)
5207                 {
5208                         DoEmit (ec, true);
5209                 }
5210
5211         }
5212
5213         /// <summary>
5214         ///   Represents the `this' construct
5215         /// </summary>
5216         public class This : Expression, IAssignMethod, IMemoryLocation, IVariable {
5217
5218                 Block block;
5219                 VariableInfo vi;
5220
5221                 public This (Block block, Location loc)
5222                 {
5223                         this.loc = loc;
5224                         this.block = block;
5225                 }
5226
5227                 public This (Location loc)
5228                 {
5229                         this.loc = loc;
5230                 }
5231
5232                 public bool IsAssigned (EmitContext ec, Location loc)
5233                 {
5234                         if (vi == null)
5235                                 return true;
5236
5237                         return vi.IsAssigned (ec, loc);
5238                 }
5239
5240                 public bool IsFieldAssigned (EmitContext ec, string field_name, Location loc)
5241                 {
5242                         if (vi == null)
5243                                 return true;
5244
5245                         return vi.IsFieldAssigned (ec, field_name, loc);
5246                 }
5247
5248                 public void SetAssigned (EmitContext ec)
5249                 {
5250                         if (vi != null)
5251                                 vi.SetAssigned (ec);
5252                 }
5253
5254                 public void SetFieldAssigned (EmitContext ec, string field_name)
5255                 {
5256                         if (vi != null)
5257                                 vi.SetFieldAssigned (ec, field_name);
5258                 }
5259
5260                 public override Expression DoResolve (EmitContext ec)
5261                 {
5262                         eclass = ExprClass.Variable;
5263                         type = ec.ContainerType;
5264
5265                         if (ec.IsStatic){
5266                                 Error (26, "Keyword this not valid in static code");
5267                                 return null;
5268                         }
5269
5270                         if (block != null)
5271                                 vi = block.ThisVariable;
5272
5273                         return this;
5274                 }
5275
5276                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5277                 {
5278                         DoResolve (ec);
5279
5280                         VariableInfo vi = ec.CurrentBlock.ThisVariable;
5281                         if (vi != null)
5282                                 vi.SetAssigned (ec);
5283
5284                         if (ec.TypeContainer is Class){
5285                                 Error (1604, "Cannot assign to `this'");
5286                                 return null;
5287                         }
5288
5289                         return this;
5290                 }
5291
5292                 public override void Emit (EmitContext ec)
5293                 {
5294                         ILGenerator ig = ec.ig;
5295
5296                         ig.Emit (OpCodes.Ldarg_0);
5297                         if (ec.TypeContainer is Struct)
5298                                 ig.Emit (OpCodes.Ldobj, type);
5299                 }
5300
5301                 public void EmitAssign (EmitContext ec, Expression source)
5302                 {
5303                         ILGenerator ig = ec.ig;
5304
5305                         if (ec.TypeContainer is Struct){
5306                                 ig.Emit (OpCodes.Ldarg_0);
5307                                 source.Emit (ec);
5308                                 ig.Emit (OpCodes.Stobj, type);
5309                         } else {
5310                                 source.Emit (ec);
5311                                 ig.Emit (OpCodes.Starg, 0);
5312                         }
5313                 }
5314
5315                 public void AddressOf (EmitContext ec, AddressOp mode)
5316                 {
5317                         ec.ig.Emit (OpCodes.Ldarg_0);
5318
5319                         // FIMXE
5320                         // FIGURE OUT WHY LDARG_S does not work
5321                         //
5322                         // consider: struct X { int val; int P { set { val = value; }}}
5323                         //
5324                         // Yes, this looks very bad. Look at `NOTAS' for
5325                         // an explanation.
5326                         // ec.ig.Emit (OpCodes.Ldarga_S, (byte) 0);
5327                 }
5328         }
5329
5330         /// <summary>
5331         ///   Implements the typeof operator
5332         /// </summary>
5333         public class TypeOf : Expression {
5334                 public readonly Expression QueriedType;
5335                 Type typearg;
5336
5337                 public TypeOf (Expression queried_type, Location l)
5338                 {
5339                         QueriedType = queried_type;
5340                         loc = l;
5341                 }
5342
5343                 public override Expression DoResolve (EmitContext ec)
5344                 {
5345                         typearg = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5346
5347                         if (typearg == null)
5348                                 return null;
5349
5350                         type = TypeManager.type_type;
5351                         eclass = ExprClass.Type;
5352                         return this;
5353                 }
5354
5355                 public override void Emit (EmitContext ec)
5356                 {
5357                         ec.ig.Emit (OpCodes.Ldtoken, typearg);
5358                         ec.ig.Emit (OpCodes.Call, TypeManager.system_type_get_type_from_handle);
5359                 }
5360
5361                 public Type TypeArg {
5362                         get { return typearg; }
5363                 }
5364         }
5365
5366         /// <summary>
5367         ///   Implements the sizeof expression
5368         /// </summary>
5369         public class SizeOf : Expression {
5370                 public readonly Expression QueriedType;
5371                 Type type_queried;
5372
5373                 public SizeOf (Expression queried_type, Location l)
5374                 {
5375                         this.QueriedType = queried_type;
5376                         loc = l;
5377                 }
5378
5379                 public override Expression DoResolve (EmitContext ec)
5380                 {
5381                         if (!ec.InUnsafe) {
5382                                 Error (233, "Sizeof may only be used in an unsafe context " +
5383                                        "(consider using System.Runtime.InteropServices.Marshal.Sizeof");
5384                                 return null;
5385                         }
5386
5387                         type_queried = ec.DeclSpace.ResolveType (QueriedType, false, loc);
5388                         if (type_queried == null)
5389                                 return null;
5390
5391                         if (!TypeManager.IsUnmanagedType (type_queried)){
5392                                 Report.Error (208, "Cannot take the size of an unmanaged type (" + TypeManager.CSharpName (type_queried) + ")");
5393                                 return null;
5394                         }
5395
5396                         type = TypeManager.int32_type;
5397                         eclass = ExprClass.Value;
5398                         return this;
5399                 }
5400
5401                 public override void Emit (EmitContext ec)
5402                 {
5403                         int size = GetTypeSize (type_queried);
5404
5405                         if (size == 0)
5406                                 ec.ig.Emit (OpCodes.Sizeof, type_queried);
5407                         else
5408                                 IntConstant.EmitInt (ec.ig, size);
5409                 }
5410         }
5411
5412         /// <summary>
5413         ///   Implements the member access expression
5414         /// </summary>
5415         public class MemberAccess : Expression, ITypeExpression {
5416                 public readonly string Identifier;
5417                 Expression expr;
5418                 Expression member_lookup;
5419
5420                 public MemberAccess (Expression expr, string id, Location l)
5421                 {
5422                         this.expr = expr;
5423                         Identifier = id;
5424                         loc = l;
5425                 }
5426
5427                 public Expression Expr {
5428                         get {
5429                                 return expr;
5430                         }
5431                 }
5432
5433                 static void error176 (Location loc, string name)
5434                 {
5435                         Report.Error (176, loc, "Static member `" +
5436                                       name + "' cannot be accessed " +
5437                                       "with an instance reference, qualify with a " +
5438                                       "type name instead");
5439                 }
5440
5441                 static bool IdenticalNameAndTypeName (EmitContext ec, Expression left_original, Location loc)
5442                 {
5443                         if (left_original == null)
5444                                 return false;
5445
5446                         if (!(left_original is SimpleName))
5447                                 return false;
5448
5449                         SimpleName sn = (SimpleName) left_original;
5450
5451                         Type t = RootContext.LookupType (ec.DeclSpace, sn.Name, true, loc);
5452                         if (t != null)
5453                                 return true;
5454
5455                         return false;
5456                 }
5457
5458                 public static Expression ResolveMemberAccess (EmitContext ec, Expression member_lookup,
5459                                                               Expression left, Location loc,
5460                                                               Expression left_original)
5461                 {
5462                         bool left_is_type, left_is_explicit;
5463
5464                         // If `left' is null, then we're called from SimpleNameResolve and this is
5465                         // a member in the currently defining class.
5466                         if (left == null) {
5467                                 left_is_type = ec.IsStatic || ec.IsFieldInitializer;
5468                                 left_is_explicit = false;
5469
5470                                 // Implicitly default to `this' unless we're static.
5471                                 if (!ec.IsStatic && !ec.IsFieldInitializer && !ec.InEnumContext)
5472                                         left = ec.This;
5473                         } else {
5474                                 left_is_type = left is TypeExpr;
5475                                 left_is_explicit = true;
5476                         }
5477
5478                         if (member_lookup is FieldExpr){
5479                                 FieldExpr fe = (FieldExpr) member_lookup;
5480                                 FieldInfo fi = fe.FieldInfo;
5481                                 Type decl_type = fi.DeclaringType;
5482
5483                                 if (fi is FieldBuilder) {
5484                                         Const c = TypeManager.LookupConstant ((FieldBuilder) fi);
5485
5486                                         if (c != null) {
5487                                                 object o = c.LookupConstantValue (ec);
5488                                                 object real_value = ((Constant) c.Expr).GetValue ();
5489
5490                                                 return Constantify (real_value, fi.FieldType);
5491                                         }
5492                                 }
5493
5494                                 if (fi.IsLiteral) {
5495                                         Type t = fi.FieldType;
5496
5497                                         object o;
5498
5499                                         if (fi is FieldBuilder)
5500                                                 o = TypeManager.GetValue ((FieldBuilder) fi);
5501                                         else
5502                                                 o = fi.GetValue (fi);
5503
5504                                         if (decl_type.IsSubclassOf (TypeManager.enum_type)) {
5505                                                 if (left_is_explicit && !left_is_type &&
5506                                                     !IdenticalNameAndTypeName (ec, left_original, loc)) {
5507                                                         error176 (loc, fe.FieldInfo.Name);
5508                                                         return null;
5509                                                 }
5510
5511                                                 Expression enum_member = MemberLookup (
5512                                                         ec, decl_type, "value__", MemberTypes.Field,
5513                                                         AllBindingFlags, loc);
5514
5515                                                 Enum en = TypeManager.LookupEnum (decl_type);
5516
5517                                                 Constant c;
5518                                                 if (en != null)
5519                                                         c = Constantify (o, en.UnderlyingType);
5520                                                 else
5521                                                         c = Constantify (o, enum_member.Type);
5522
5523                                                 return new EnumConstant (c, decl_type);
5524                                         }
5525
5526                                         Expression exp = Constantify (o, t);
5527
5528                                         if (left_is_explicit && !left_is_type) {
5529                                                 error176 (loc, fe.FieldInfo.Name);
5530                                                 return null;
5531                                         }
5532
5533                                         return exp;
5534                                 }
5535
5536                                 if (fi.FieldType.IsPointer && !ec.InUnsafe){
5537                                         UnsafeError (loc);
5538                                         return null;
5539                                 }
5540                         }
5541
5542                         if (member_lookup is EventExpr) {
5543
5544                                 EventExpr ee = (EventExpr) member_lookup;
5545
5546                                 //
5547                                 // If the event is local to this class, we transform ourselves into
5548                                 // a FieldExpr
5549                                 //
5550
5551                                 if (ee.EventInfo.DeclaringType == ec.ContainerType) {
5552                                         MemberInfo mi = GetFieldFromEvent (ee);
5553
5554                                         if (mi == null) {
5555                                                 //
5556                                                 // If this happens, then we have an event with its own
5557                                                 // accessors and private field etc so there's no need
5558                                                 // to transform ourselves : we should instead flag an error
5559                                                 //
5560                                                 Assign.error70 (ee.EventInfo, loc);
5561                                                 return null;
5562                                         }
5563
5564                                         Expression ml = ExprClassFromMemberInfo (ec, mi, loc);
5565
5566                                         if (ml == null) {
5567                                                 Report.Error (-200, loc, "Internal error!!");
5568                                                 return null;
5569                                         }
5570
5571                                         return ResolveMemberAccess (ec, ml, left, loc, left_original);
5572                                 }
5573                         }
5574
5575                         if (member_lookup is IMemberExpr) {
5576                                 IMemberExpr me = (IMemberExpr) member_lookup;
5577
5578                                 if (left_is_type){
5579                                         MethodGroupExpr mg = me as MethodGroupExpr;
5580                                         if ((mg != null) && left_is_explicit && left.Type.IsInterface)
5581                                                 mg.IsExplicitImpl = left_is_explicit;
5582
5583                                         if (!me.IsStatic){
5584                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5585                                                         return member_lookup;
5586
5587                                                 SimpleName.Error_ObjectRefRequired (ec, loc, me.Name);
5588                                                 return null;
5589                                         }
5590
5591                                 } else {
5592                                         if (!me.IsInstance){
5593                                                 if (IdenticalNameAndTypeName (ec, left_original, loc))
5594                                                         return member_lookup;
5595
5596                                                 if (left_is_explicit) {
5597                                                         error176 (loc, me.Name);
5598                                                         return null;
5599                                                 }
5600                                         }
5601
5602                                         //
5603                                         // Since we can not check for instance objects in SimpleName,
5604                                         // becaue of the rule that allows types and variables to share
5605                                         // the name (as long as they can be de-ambiguated later, see
5606                                         // IdenticalNameAndTypeName), we have to check whether left
5607                                         // is an instance variable in a static context
5608                                         //
5609                                         // However, if the left-hand value is explicitly given, then
5610                                         // it is already our instance expression, so we aren't in
5611                                         // static context.
5612                                         //
5613
5614                                         if (ec.IsStatic && !left_is_explicit && left is IMemberExpr){
5615                                                 IMemberExpr mexp = (IMemberExpr) left;
5616
5617                                                 if (!mexp.IsStatic){
5618                                                         SimpleName.Error_ObjectRefRequired (ec, loc, mexp.Name);
5619                                                         return null;
5620                                                 }
5621                                         }
5622
5623                                         me.InstanceExpression = left;
5624                                 }
5625
5626                                 return member_lookup;
5627                         }
5628
5629                         if (member_lookup is TypeExpr){
5630                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5631                                 return member_lookup;
5632                         }
5633
5634                         Console.WriteLine ("Left is: " + left);
5635                         Report.Error (-100, loc, "Support for [" + member_lookup + "] is not present yet");
5636                         Environment.Exit (0);
5637                         return null;
5638                 }
5639
5640                 public Expression DoResolve (EmitContext ec, Expression right_side, ResolveFlags flags)
5641                 {
5642                         if (type != null)
5643                                 throw new Exception ();
5644                         //
5645                         // Resolve the expression with flow analysis turned off, we'll do the definite
5646                         // assignment checks later.  This is because we don't know yet what the expression
5647                         // will resolve to - it may resolve to a FieldExpr and in this case we must do the
5648                         // definite assignment check on the actual field and not on the whole struct.
5649                         //
5650
5651                         Expression original = expr;
5652                         expr = expr.Resolve (ec, flags | ResolveFlags.DisableFlowAnalysis);
5653
5654                         if (expr == null)
5655                                 return null;
5656
5657                         if (expr is SimpleName){
5658                                 SimpleName child_expr = (SimpleName) expr;
5659
5660                                 Expression new_expr = new SimpleName (child_expr.Name + "." + Identifier, loc);
5661
5662                                 return new_expr.Resolve (ec, flags);
5663                         }
5664
5665                         //
5666                         // TODO: I mailed Ravi about this, and apparently we can get rid
5667                         // of this and put it in the right place.
5668                         //
5669                         // Handle enums here when they are in transit.
5670                         // Note that we cannot afford to hit MemberLookup in this case because
5671                         // it will fail to find any members at all
5672                         //
5673
5674                         int errors = Report.Errors;
5675
5676                         Type expr_type = expr.Type;
5677                         if ((expr is TypeExpr) && (expr_type.IsSubclassOf (TypeManager.enum_type))){
5678
5679                                 Enum en = TypeManager.LookupEnum (expr_type);
5680
5681                                 if (en != null) {
5682                                         object value = en.LookupEnumValue (ec, Identifier, loc);
5683
5684                                         if (value != null){
5685                                                 Constant c = Constantify (value, en.UnderlyingType);
5686                                                 return new EnumConstant (c, expr_type);
5687                                         }
5688                                 }
5689                         }
5690
5691                         if (expr_type.IsPointer){
5692                                 Error (23, "The `.' operator can not be applied to pointer operands (" +
5693                                        TypeManager.CSharpName (expr_type) + ")");
5694                                 return null;
5695                         }
5696
5697                         member_lookup = MemberLookup (ec, expr_type, Identifier, loc);
5698
5699                         if (member_lookup == null){
5700                                 // Error has already been reported.
5701                                 if (errors < Report.Errors)
5702                                         return null;
5703
5704                                 //
5705                                 // Try looking the member up from the same type, if we find
5706                                 // it, we know that the error was due to limited visibility
5707                                 //
5708                                 object lookup = TypeManager.MemberLookup (
5709                                         expr_type, expr_type, AllMemberTypes, AllBindingFlags |
5710                                         BindingFlags.NonPublic, Identifier);
5711                                 if (lookup == null)
5712                                         Error (117, "`" + expr_type + "' does not contain a " +
5713                                                "definition for `" + Identifier + "'");
5714                                 else if ((expr_type != ec.ContainerType) &&
5715                                          ec.ContainerType.IsSubclassOf (expr_type)){
5716
5717                                         // Although a derived class can access protected members of
5718                                         // its base class it cannot do so through an instance of the
5719                                         // base class (CS1540).  If the expr_type is a parent of the
5720                                         // ec.ContainerType and the lookup succeeds with the latter one,
5721                                         // then we are in this situation.
5722
5723                                         lookup = TypeManager.MemberLookup (
5724                                                 ec.ContainerType, ec.ContainerType, AllMemberTypes,
5725                                                 AllBindingFlags, Identifier);
5726
5727                                         if (lookup != null)
5728                                                 Error (1540, "Cannot access protected member `" +
5729                                                        expr_type + "." + Identifier + "' " +
5730                                                        "via a qualifier of type `" +
5731                                                        TypeManager.CSharpName (expr_type) + "'; the " +
5732                                                        "qualifier must be of type `" +
5733                                                        TypeManager.CSharpName (ec.ContainerType) + "' " +
5734                                                        "(or derived from it)");
5735                                         else
5736                                                 Error (122, "`" + expr_type + "." + Identifier + "' " +
5737                                                        "is inaccessible because of its protection level");
5738                                 } else
5739                                         Error (122, "`" + expr_type + "." + Identifier + "' " +
5740                                                "is inaccessible because of its protection level");
5741
5742                                 return null;
5743                         }
5744
5745                         if (member_lookup is TypeExpr){
5746                                 member_lookup.Resolve (ec, ResolveFlags.Type);
5747                                 return member_lookup;
5748                         } else if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
5749                                 return null;
5750
5751                         member_lookup = ResolveMemberAccess (ec, member_lookup, expr, loc, original);
5752                         if (member_lookup == null)
5753                                 return null;
5754
5755                         // The following DoResolve/DoResolveLValue will do the definite assignment
5756                         // check.
5757
5758                         if (right_side != null)
5759                                 member_lookup = member_lookup.DoResolveLValue (ec, right_side);
5760                         else
5761                                 member_lookup = member_lookup.DoResolve (ec);
5762
5763                         return member_lookup;
5764                 }
5765
5766                 public override Expression DoResolve (EmitContext ec)
5767                 {
5768                         return DoResolve (ec, null, ResolveFlags.VariableOrValue |
5769                                           ResolveFlags.SimpleName | ResolveFlags.Type);
5770                 }
5771
5772                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5773                 {
5774                         return DoResolve (ec, right_side, ResolveFlags.VariableOrValue |
5775                                           ResolveFlags.SimpleName | ResolveFlags.Type);
5776                 }
5777
5778                 public Expression DoResolveType (EmitContext ec)
5779                 {
5780                         return DoResolve (ec, null, ResolveFlags.Type);
5781                 }
5782
5783                 public override void Emit (EmitContext ec)
5784                 {
5785                         throw new Exception ("Should not happen");
5786                 }
5787
5788                 public override string ToString ()
5789                 {
5790                         return expr + "." + Identifier;
5791                 }
5792         }
5793
5794         /// <summary>
5795         ///   Implements checked expressions
5796         /// </summary>
5797         public class CheckedExpr : Expression {
5798
5799                 public Expression Expr;
5800
5801                 public CheckedExpr (Expression e, Location l)
5802                 {
5803                         Expr = e;
5804                         loc = l;
5805                 }
5806
5807                 public override Expression DoResolve (EmitContext ec)
5808                 {
5809                         bool last_const_check = ec.ConstantCheckState;
5810
5811                         ec.ConstantCheckState = true;
5812                         Expr = Expr.Resolve (ec);
5813                         ec.ConstantCheckState = last_const_check;
5814
5815                         if (Expr == null)
5816                                 return null;
5817
5818                         if (Expr is Constant)
5819                                 return Expr;
5820
5821                         eclass = Expr.eclass;
5822                         type = Expr.Type;
5823                         return this;
5824                 }
5825
5826                 public override void Emit (EmitContext ec)
5827                 {
5828                         bool last_check = ec.CheckState;
5829                         bool last_const_check = ec.ConstantCheckState;
5830
5831                         ec.CheckState = true;
5832                         ec.ConstantCheckState = true;
5833                         Expr.Emit (ec);
5834                         ec.CheckState = last_check;
5835                         ec.ConstantCheckState = last_const_check;
5836                 }
5837
5838         }
5839
5840         /// <summary>
5841         ///   Implements the unchecked expression
5842         /// </summary>
5843         public class UnCheckedExpr : Expression {
5844
5845                 public Expression Expr;
5846
5847                 public UnCheckedExpr (Expression e, Location l)
5848                 {
5849                         Expr = e;
5850                         loc = l;
5851                 }
5852
5853                 public override Expression DoResolve (EmitContext ec)
5854                 {
5855                         bool last_const_check = ec.ConstantCheckState;
5856
5857                         ec.ConstantCheckState = false;
5858                         Expr = Expr.Resolve (ec);
5859                         ec.ConstantCheckState = last_const_check;
5860
5861                         if (Expr == null)
5862                                 return null;
5863
5864                         if (Expr is Constant)
5865                                 return Expr;
5866
5867                         eclass = Expr.eclass;
5868                         type = Expr.Type;
5869                         return this;
5870                 }
5871
5872                 public override void Emit (EmitContext ec)
5873                 {
5874                         bool last_check = ec.CheckState;
5875                         bool last_const_check = ec.ConstantCheckState;
5876
5877                         ec.CheckState = false;
5878                         ec.ConstantCheckState = false;
5879                         Expr.Emit (ec);
5880                         ec.CheckState = last_check;
5881                         ec.ConstantCheckState = last_const_check;
5882                 }
5883
5884         }
5885
5886         /// <summary>
5887         ///   An Element Access expression.
5888         ///
5889         ///   During semantic analysis these are transformed into
5890         ///   IndexerAccess or ArrayAccess
5891         /// </summary>
5892         public class ElementAccess : Expression {
5893                 public ArrayList  Arguments;
5894                 public Expression Expr;
5895
5896                 public ElementAccess (Expression e, ArrayList e_list, Location l)
5897                 {
5898                         Expr = e;
5899
5900                         loc  = l;
5901
5902                         if (e_list == null)
5903                                 return;
5904
5905                         Arguments = new ArrayList ();
5906                         foreach (Expression tmp in e_list)
5907                                 Arguments.Add (new Argument (tmp, Argument.AType.Expression));
5908
5909                 }
5910
5911                 bool CommonResolve (EmitContext ec)
5912                 {
5913                         Expr = Expr.Resolve (ec);
5914
5915                         if (Expr == null)
5916                                 return false;
5917
5918                         if (Arguments == null)
5919                                 return false;
5920
5921                         foreach (Argument a in Arguments){
5922                                 if (!a.Resolve (ec, loc))
5923                                         return false;
5924                         }
5925
5926                         return true;
5927                 }
5928
5929                 Expression MakePointerAccess ()
5930                 {
5931                         Type t = Expr.Type;
5932
5933                         if (t == TypeManager.void_ptr_type){
5934                                 Error (
5935                                         242,
5936                                         "The array index operation is not valid for void pointers");
5937                                 return null;
5938                         }
5939                         if (Arguments.Count != 1){
5940                                 Error (
5941                                         196,
5942                                         "A pointer must be indexed by a single value");
5943                                 return null;
5944                         }
5945                         Expression p = new PointerArithmetic (true, Expr, ((Argument)Arguments [0]).Expr,
5946                                                               t, loc);
5947                         return new Indirection (p, loc);
5948                 }
5949
5950                 public override Expression DoResolve (EmitContext ec)
5951                 {
5952                         if (!CommonResolve (ec))
5953                                 return null;
5954
5955                         //
5956                         // We perform some simple tests, and then to "split" the emit and store
5957                         // code we create an instance of a different class, and return that.
5958                         //
5959                         // I am experimenting with this pattern.
5960                         //
5961                         Type t = Expr.Type;
5962
5963                         if (t.IsArray)
5964                                 return (new ArrayAccess (this, loc)).Resolve (ec);
5965                         else if (t.IsPointer)
5966                                 return MakePointerAccess ();
5967                         else
5968                                 return (new IndexerAccess (this, loc)).Resolve (ec);
5969                 }
5970
5971                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5972                 {
5973                         if (!CommonResolve (ec))
5974                                 return null;
5975
5976                         Type t = Expr.Type;
5977                         if (t.IsArray)
5978                                 return (new ArrayAccess (this, loc)).ResolveLValue (ec, right_side);
5979                         else if (t.IsPointer)
5980                                 return MakePointerAccess ();
5981                         else
5982                                 return (new IndexerAccess (this, loc)).ResolveLValue (ec, right_side);
5983                 }
5984
5985                 public override void Emit (EmitContext ec)
5986                 {
5987                         throw new Exception ("Should never be reached");
5988                 }
5989         }
5990
5991         /// <summary>
5992         ///   Implements array access
5993         /// </summary>
5994         public class ArrayAccess : Expression, IAssignMethod, IMemoryLocation {
5995                 //
5996                 // Points to our "data" repository
5997                 //
5998                 ElementAccess ea;
5999
6000                 LocalTemporary [] cached_locations;
6001
6002                 public ArrayAccess (ElementAccess ea_data, Location l)
6003                 {
6004                         ea = ea_data;
6005                         eclass = ExprClass.Variable;
6006                         loc = l;
6007                 }
6008
6009                 public override Expression DoResolve (EmitContext ec)
6010                 {
6011                         ExprClass eclass = ea.Expr.eclass;
6012
6013 #if false
6014                         // As long as the type is valid
6015                         if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
6016                               eclass == ExprClass.Value)) {
6017                                 ea.Expr.Error118 ("variable or value");
6018                                 return null;
6019                         }
6020 #endif
6021
6022                         Type t = ea.Expr.Type;
6023                         if (t.GetArrayRank () != ea.Arguments.Count){
6024                                 ea.Error (22,
6025                                           "Incorrect number of indexes for array " +
6026                                           " expected: " + t.GetArrayRank () + " got: " +
6027                                           ea.Arguments.Count);
6028                                 return null;
6029                         }
6030                         type = TypeManager.TypeToCoreType (t.GetElementType ());
6031                         if (type.IsPointer && !ec.InUnsafe){
6032                                 UnsafeError (ea.Location);
6033                                 return null;
6034                         }
6035
6036                         foreach (Argument a in ea.Arguments){
6037                                 Type argtype = a.Type;
6038
6039                                 if (argtype == TypeManager.int32_type ||
6040                                     argtype == TypeManager.uint32_type ||
6041                                     argtype == TypeManager.int64_type ||
6042                                     argtype == TypeManager.uint64_type)
6043                                         continue;
6044
6045                                 //
6046                                 // Mhm.  This is strage, because the Argument.Type is not the same as
6047                                 // Argument.Expr.Type: the value changes depending on the ref/out setting.
6048                                 //
6049                                 // Wonder if I will run into trouble for this.
6050                                 //
6051                                 a.Expr = ExpressionToArrayArgument (ec, a.Expr, ea.Location);
6052                                 if (a.Expr == null)
6053                                         return null;
6054                         }
6055
6056                         eclass = ExprClass.Variable;
6057
6058                         return this;
6059                 }
6060
6061                 /// <summary>
6062                 ///    Emits the right opcode to load an object of Type `t'
6063                 ///    from an array of T
6064                 /// </summary>
6065                 static public void EmitLoadOpcode (ILGenerator ig, Type type)
6066                 {
6067                         if (type == TypeManager.byte_type || type == TypeManager.bool_type)
6068                                 ig.Emit (OpCodes.Ldelem_U1);
6069                         else if (type == TypeManager.sbyte_type)
6070                                 ig.Emit (OpCodes.Ldelem_I1);
6071                         else if (type == TypeManager.short_type)
6072                                 ig.Emit (OpCodes.Ldelem_I2);
6073                         else if (type == TypeManager.ushort_type || type == TypeManager.char_type)
6074                                 ig.Emit (OpCodes.Ldelem_U2);
6075                         else if (type == TypeManager.int32_type)
6076                                 ig.Emit (OpCodes.Ldelem_I4);
6077                         else if (type == TypeManager.uint32_type)
6078                                 ig.Emit (OpCodes.Ldelem_U4);
6079                         else if (type == TypeManager.uint64_type)
6080                                 ig.Emit (OpCodes.Ldelem_I8);
6081                         else if (type == TypeManager.int64_type)
6082                                 ig.Emit (OpCodes.Ldelem_I8);
6083                         else if (type == TypeManager.float_type)
6084                                 ig.Emit (OpCodes.Ldelem_R4);
6085                         else if (type == TypeManager.double_type)
6086                                 ig.Emit (OpCodes.Ldelem_R8);
6087                         else if (type == TypeManager.intptr_type)
6088                                 ig.Emit (OpCodes.Ldelem_I);
6089                         else if (type.IsValueType){
6090                                 ig.Emit (OpCodes.Ldelema, type);
6091                                 ig.Emit (OpCodes.Ldobj, type);
6092                         } else
6093                                 ig.Emit (OpCodes.Ldelem_Ref);
6094                 }
6095
6096                 /// <summary>
6097                 ///    Emits the right opcode to store an object of Type `t'
6098                 ///    from an array of T.
6099                 /// </summary>
6100                 static public void EmitStoreOpcode (ILGenerator ig, Type t)
6101                 {
6102                         t = TypeManager.TypeToCoreType (t);
6103                         if (TypeManager.IsEnumType (t) && t != TypeManager.enum_type)
6104                                 t = TypeManager.EnumToUnderlying (t);
6105                         if (t == TypeManager.byte_type || t == TypeManager.sbyte_type ||
6106                             t == TypeManager.bool_type)
6107                                 ig.Emit (OpCodes.Stelem_I1);
6108                         else if (t == TypeManager.short_type || t == TypeManager.ushort_type || t == TypeManager.char_type)
6109                                 ig.Emit (OpCodes.Stelem_I2);
6110                         else if (t == TypeManager.int32_type || t == TypeManager.uint32_type)
6111                                 ig.Emit (OpCodes.Stelem_I4);
6112                         else if (t == TypeManager.int64_type || t == TypeManager.uint64_type)
6113                                 ig.Emit (OpCodes.Stelem_I8);
6114                         else if (t == TypeManager.float_type)
6115                                 ig.Emit (OpCodes.Stelem_R4);
6116                         else if (t == TypeManager.double_type)
6117                                 ig.Emit (OpCodes.Stelem_R8);
6118                         else if (t == TypeManager.intptr_type)
6119                                 ig.Emit (OpCodes.Stelem_I);
6120                         else if (t.IsValueType){
6121                                 ig.Emit (OpCodes.Stobj, t);
6122                         } else
6123                                 ig.Emit (OpCodes.Stelem_Ref);
6124                 }
6125
6126                 MethodInfo FetchGetMethod ()
6127                 {
6128                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6129                         int arg_count = ea.Arguments.Count;
6130                         Type [] args = new Type [arg_count];
6131                         MethodInfo get;
6132
6133                         for (int i = 0; i < arg_count; i++){
6134                                 //args [i++] = a.Type;
6135                                 args [i] = TypeManager.int32_type;
6136                         }
6137
6138                         get = mb.GetArrayMethod (
6139                                 ea.Expr.Type, "Get",
6140                                 CallingConventions.HasThis |
6141                                 CallingConventions.Standard,
6142                                 type, args);
6143                         return get;
6144                 }
6145
6146
6147                 MethodInfo FetchAddressMethod ()
6148                 {
6149                         ModuleBuilder mb = CodeGen.ModuleBuilder;
6150                         int arg_count = ea.Arguments.Count;
6151                         Type [] args = new Type [arg_count];
6152                         MethodInfo address;
6153                         string ptr_type_name;
6154                         Type ret_type;
6155
6156                         ptr_type_name = type.FullName + "&";
6157                         ret_type = Type.GetType (ptr_type_name);
6158
6159                         //
6160                         // It is a type defined by the source code we are compiling
6161                         //
6162                         if (ret_type == null){
6163                                 ret_type = mb.GetType (ptr_type_name);
6164                         }
6165
6166                         for (int i = 0; i < arg_count; i++){
6167                                 //args [i++] = a.Type;
6168                                 args [i] = TypeManager.int32_type;
6169                         }
6170
6171                         address = mb.GetArrayMethod (
6172                                 ea.Expr.Type, "Address",
6173                                 CallingConventions.HasThis |
6174                                 CallingConventions.Standard,
6175                                 ret_type, args);
6176
6177                         return address;
6178                 }
6179
6180                 //
6181                 // Load the array arguments into the stack.
6182                 //
6183                 // If we have been requested to cache the values (cached_locations array
6184                 // initialized), then load the arguments the first time and store them
6185                 // in locals.  otherwise load from local variables.
6186                 //
6187                 void LoadArrayAndArguments (EmitContext ec)
6188                 {
6189                         ILGenerator ig = ec.ig;
6190
6191                         if (cached_locations == null){
6192                                 ea.Expr.Emit (ec);
6193                                 foreach (Argument a in ea.Arguments){
6194                                         Type argtype = a.Expr.Type;
6195
6196                                         a.Expr.Emit (ec);
6197
6198                                         if (argtype == TypeManager.int64_type)
6199                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6200                                         else if (argtype == TypeManager.uint64_type)
6201                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6202                                 }
6203                                 return;
6204                         }
6205
6206                         if (cached_locations [0] == null){
6207                                 cached_locations [0] = new LocalTemporary (ec, ea.Expr.Type);
6208                                 ea.Expr.Emit (ec);
6209                                 ig.Emit (OpCodes.Dup);
6210                                 cached_locations [0].Store (ec);
6211
6212                                 int j = 1;
6213
6214                                 foreach (Argument a in ea.Arguments){
6215                                         Type argtype = a.Expr.Type;
6216
6217                                         cached_locations [j] = new LocalTemporary (ec, TypeManager.intptr_type /* a.Expr.Type */);
6218                                         a.Expr.Emit (ec);
6219                                         if (argtype == TypeManager.int64_type)
6220                                                 ig.Emit (OpCodes.Conv_Ovf_I);
6221                                         else if (argtype == TypeManager.uint64_type)
6222                                                 ig.Emit (OpCodes.Conv_Ovf_I_Un);
6223
6224                                         ig.Emit (OpCodes.Dup);
6225                                         cached_locations [j].Store (ec);
6226                                         j++;
6227                                 }
6228                                 return;
6229                         }
6230
6231                         foreach (LocalTemporary lt in cached_locations)
6232                                 lt.Emit (ec);
6233                 }
6234
6235                 public new void CacheTemporaries (EmitContext ec)
6236                 {
6237                         cached_locations = new LocalTemporary [ea.Arguments.Count + 1];
6238                 }
6239
6240                 public override void Emit (EmitContext ec)
6241                 {
6242                         int rank = ea.Expr.Type.GetArrayRank ();
6243                         ILGenerator ig = ec.ig;
6244
6245                         LoadArrayAndArguments (ec);
6246
6247                         if (rank == 1)
6248                                 EmitLoadOpcode (ig, type);
6249                         else {
6250                                 MethodInfo method;
6251
6252                                 method = FetchGetMethod ();
6253                                 ig.Emit (OpCodes.Call, method);
6254                         }
6255                 }
6256
6257                 public void EmitAssign (EmitContext ec, Expression source)
6258                 {
6259                         int rank = ea.Expr.Type.GetArrayRank ();
6260                         ILGenerator ig = ec.ig;
6261                         Type t = source.Type;
6262
6263                         LoadArrayAndArguments (ec);
6264
6265                         //
6266                         // The stobj opcode used by value types will need
6267                         // an address on the stack, not really an array/array
6268                         // pair
6269                         //
6270                         if (rank == 1){
6271                                 if (t == TypeManager.enum_type || t == TypeManager.decimal_type ||
6272                                     (t.IsSubclassOf (TypeManager.value_type) && !TypeManager.IsEnumType (t) && !TypeManager.IsBuiltinType (t)))
6273                                         ig.Emit (OpCodes.Ldelema, t);
6274                         }
6275
6276                         source.Emit (ec);
6277
6278                         if (rank == 1)
6279                                 EmitStoreOpcode (ig, t);
6280                         else {
6281                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
6282                                 int arg_count = ea.Arguments.Count;
6283                                 Type [] args = new Type [arg_count + 1];
6284                                 MethodInfo set;
6285
6286                                 for (int i = 0; i < arg_count; i++){
6287                                         //args [i++] = a.Type;
6288                                         args [i] = TypeManager.int32_type;
6289                                 }
6290
6291                                 args [arg_count] = type;
6292
6293                                 set = mb.GetArrayMethod (
6294                                         ea.Expr.Type, "Set",
6295                                         CallingConventions.HasThis |
6296                                         CallingConventions.Standard,
6297                                         TypeManager.void_type, args);
6298
6299                                 ig.Emit (OpCodes.Call, set);
6300                         }
6301                 }
6302
6303                 public void AddressOf (EmitContext ec, AddressOp mode)
6304                 {
6305                         int rank = ea.Expr.Type.GetArrayRank ();
6306                         ILGenerator ig = ec.ig;
6307
6308                         LoadArrayAndArguments (ec);
6309
6310                         if (rank == 1){
6311                                 ig.Emit (OpCodes.Ldelema, type);
6312                         } else {
6313                                 MethodInfo address = FetchAddressMethod ();
6314                                 ig.Emit (OpCodes.Call, address);
6315                         }
6316                 }
6317         }
6318
6319
6320         class Indexers {
6321                 public ArrayList getters, setters;
6322                 static Hashtable map;
6323
6324                 static Indexers ()
6325                 {
6326                         map = new Hashtable ();
6327                 }
6328
6329                 Indexers (MemberInfo [] mi)
6330                 {
6331                         foreach (PropertyInfo property in mi){
6332                                 MethodInfo get, set;
6333
6334                                 get = property.GetGetMethod (true);
6335                                 if (get != null){
6336                                         if (getters == null)
6337                                                 getters = new ArrayList ();
6338
6339                                         getters.Add (get);
6340                                 }
6341
6342                                 set = property.GetSetMethod (true);
6343                                 if (set != null){
6344                                         if (setters == null)
6345                                                 setters = new ArrayList ();
6346                                         setters.Add (set);
6347                                 }
6348                         }
6349                 }
6350
6351                 static private Indexers GetIndexersForTypeOrInterface (Type caller_type, Type lookup_type)
6352                 {
6353                         Indexers ix = (Indexers) map [lookup_type];
6354
6355                         if (ix != null)
6356                                 return ix;
6357
6358                         string p_name = TypeManager.IndexerPropertyName (lookup_type);
6359
6360                         MemberInfo [] mi = TypeManager.MemberLookup (
6361                                 caller_type, lookup_type, MemberTypes.Property,
6362                                 BindingFlags.Public | BindingFlags.Instance, p_name);
6363
6364                         if (mi == null || mi.Length == 0)
6365                                 return null;
6366
6367                         ix = new Indexers (mi);
6368                         map [lookup_type] = ix;
6369
6370                         return ix;
6371                 }
6372
6373                 static public Indexers GetIndexersForType (Type caller_type, Type lookup_type, Location loc)
6374                 {
6375                         Indexers ix = (Indexers) map [lookup_type];
6376
6377                         if (ix != null)
6378                                 return ix;
6379
6380                         ix = GetIndexersForTypeOrInterface (caller_type, lookup_type);
6381                         if (ix != null)
6382                                 return ix;
6383
6384                         Type [] ifaces = TypeManager.GetInterfaces (lookup_type);
6385                         if (ifaces != null) {
6386                                 foreach (Type itype in ifaces) {
6387                                         ix = GetIndexersForTypeOrInterface (caller_type, itype);
6388                                         if (ix != null)
6389                                                 return ix;
6390                                 }
6391                         }
6392
6393                         Report.Error (21, loc,
6394                                       "Type `" + TypeManager.CSharpName (lookup_type) +
6395                                       "' does not have any indexers defined");
6396                         return null;
6397                 }
6398         }
6399
6400         /// <summary>
6401         ///   Expressions that represent an indexer call.
6402         /// </summary>
6403         public class IndexerAccess : Expression, IAssignMethod {
6404                 //
6405                 // Points to our "data" repository
6406                 //
6407                 MethodInfo get, set;
6408                 Indexers ilist;
6409                 ArrayList set_arguments;
6410                 bool is_base_indexer;
6411
6412                 protected Type indexer_type;
6413                 protected Type current_type;
6414                 protected Expression instance_expr;
6415                 protected ArrayList arguments;
6416
6417                 public IndexerAccess (ElementAccess ea, Location loc)
6418                         : this (ea.Expr, false, loc)
6419                 {
6420                         this.arguments = ea.Arguments;
6421                 }
6422
6423                 protected IndexerAccess (Expression instance_expr, bool is_base_indexer,
6424                                          Location loc)
6425                 {
6426                         this.instance_expr = instance_expr;
6427                         this.is_base_indexer = is_base_indexer;
6428                         this.eclass = ExprClass.Value;
6429                         this.loc = loc;
6430                 }
6431
6432                 protected virtual bool CommonResolve (EmitContext ec)
6433                 {
6434                         indexer_type = instance_expr.Type;
6435                         current_type = ec.ContainerType;
6436
6437                         return true;
6438                 }
6439
6440                 public override Expression DoResolve (EmitContext ec)
6441                 {
6442                         if (!CommonResolve (ec))
6443                                 return null;
6444
6445                         //
6446                         // Step 1: Query for all `Item' *properties*.  Notice
6447                         // that the actual methods are pointed from here.
6448                         //
6449                         // This is a group of properties, piles of them.
6450
6451                         if (ilist == null)
6452                                 ilist = Indexers.GetIndexersForType (
6453                                         current_type, indexer_type, loc);
6454
6455                         //
6456                         // Step 2: find the proper match
6457                         //
6458                         if (ilist != null && ilist.getters != null && ilist.getters.Count > 0)
6459                                 get = (MethodInfo) Invocation.OverloadResolve (
6460                                         ec, new MethodGroupExpr (ilist.getters, loc), arguments, loc);
6461
6462                         if (get == null){
6463                                 Error (154, "indexer can not be used in this context, because " +
6464                                        "it lacks a `get' accessor");
6465                                 return null;
6466                         }
6467
6468                         type = get.ReturnType;
6469                         if (type.IsPointer && !ec.InUnsafe){
6470                                 UnsafeError (loc);
6471                                 return null;
6472                         }
6473
6474                         eclass = ExprClass.IndexerAccess;
6475                         return this;
6476                 }
6477
6478                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6479                 {
6480                         if (!CommonResolve (ec))
6481                                 return null;
6482
6483                         Type right_type = right_side.Type;
6484
6485                         if (ilist == null)
6486                                 ilist = Indexers.GetIndexersForType (
6487                                         current_type, indexer_type, loc);
6488
6489                         if (ilist != null && ilist.setters != null && ilist.setters.Count > 0){
6490                                 set_arguments = (ArrayList) arguments.Clone ();
6491                                 set_arguments.Add (new Argument (right_side, Argument.AType.Expression));
6492
6493                                 set = (MethodInfo) Invocation.OverloadResolve (
6494                                         ec, new MethodGroupExpr (ilist.setters, loc), set_arguments, loc);
6495                         }
6496
6497                         if (set == null){
6498                                 Error (200, "indexer X.this [" + TypeManager.CSharpName (right_type) +
6499                                        "] lacks a `set' accessor");
6500                                 return null;
6501                         }
6502
6503                         type = TypeManager.void_type;
6504                         eclass = ExprClass.IndexerAccess;
6505                         return this;
6506                 }
6507
6508                 public override void Emit (EmitContext ec)
6509                 {
6510                         Invocation.EmitCall (ec, false, false, instance_expr, get, arguments, loc);
6511                 }
6512
6513                 //
6514                 // source is ignored, because we already have a copy of it from the
6515                 // LValue resolution and we have already constructed a pre-cached
6516                 // version of the arguments (ea.set_arguments);
6517                 //
6518                 public void EmitAssign (EmitContext ec, Expression source)
6519                 {
6520                         Invocation.EmitCall (ec, false, false, instance_expr, set, set_arguments, loc);
6521                 }
6522         }
6523
6524         /// <summary>
6525         ///   The base operator for method names
6526         /// </summary>
6527         public class BaseAccess : Expression {
6528                 string member;
6529
6530                 public BaseAccess (string member, Location l)
6531                 {
6532                         this.member = member;
6533                         loc = l;
6534                 }
6535
6536                 public override Expression DoResolve (EmitContext ec)
6537                 {
6538                         Expression c = CommonResolve (ec);
6539
6540                         if (c == null)
6541                                 return null;
6542
6543                         //
6544                         // MethodGroups use this opportunity to flag an error on lacking ()
6545                         //
6546                         if (!(c is MethodGroupExpr))
6547                                 return c.Resolve (ec);
6548                         return c;
6549                 }
6550
6551                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
6552                 {
6553                         Expression c = CommonResolve (ec);
6554
6555                         if (c == null)
6556                                 return null;
6557
6558                         //
6559                         // MethodGroups use this opportunity to flag an error on lacking ()
6560                         //
6561                         if (! (c is MethodGroupExpr))
6562                                 return c.DoResolveLValue (ec, right_side);
6563
6564                         return c;
6565                 }
6566
6567                 Expression CommonResolve (EmitContext ec)
6568                 {
6569                         Expression member_lookup;
6570                         Type current_type = ec.ContainerType;
6571                         Type base_type = current_type.BaseType;
6572                         Expression e;
6573
6574                         if (ec.IsStatic){
6575                                 Error (1511, "Keyword base is not allowed in static method");
6576                                 return null;
6577                         }
6578
6579                         member_lookup = MemberLookup (ec, base_type, base_type, member,
6580                                                       AllMemberTypes, AllBindingFlags, loc);
6581                         if (member_lookup == null) {
6582                                 Error (117, TypeManager.CSharpName (base_type) + " does not " +
6583                                        "contain a definition for `" + member + "'");
6584                                 return null;
6585                         }
6586
6587                         Expression left;
6588
6589                         if (ec.IsStatic)
6590                                 left = new TypeExpr (base_type, loc);
6591                         else
6592                                 left = ec.This;
6593
6594                         e = MemberAccess.ResolveMemberAccess (ec, member_lookup, left, loc, null);
6595
6596                         if (e is PropertyExpr){
6597                                 PropertyExpr pe = (PropertyExpr) e;
6598
6599                                 pe.IsBase = true;
6600                         }
6601
6602                         return e;
6603                 }
6604
6605                 public override void Emit (EmitContext ec)
6606                 {
6607                         throw new Exception ("Should never be called");
6608                 }
6609         }
6610
6611         /// <summary>
6612         ///   The base indexer operator
6613         /// </summary>
6614         public class BaseIndexerAccess : IndexerAccess {
6615                 public BaseIndexerAccess (ArrayList args, Location loc)
6616                         : base (null, true, loc)
6617                 {
6618                         arguments = new ArrayList ();
6619                         foreach (Expression tmp in args)
6620                                 arguments.Add (new Argument (tmp, Argument.AType.Expression));
6621                 }
6622
6623                 protected override bool CommonResolve (EmitContext ec)
6624                 {
6625                         instance_expr = ec.This;
6626
6627                         current_type = ec.ContainerType.BaseType;
6628                         indexer_type = current_type;
6629
6630                         foreach (Argument a in arguments){
6631                                 if (!a.Resolve (ec, loc))
6632                                         return false;
6633                         }
6634
6635                         return true;
6636                 }
6637         }
6638
6639         /// <summary>
6640         ///   This class exists solely to pass the Type around and to be a dummy
6641         ///   that can be passed to the conversion functions (this is used by
6642         ///   foreach implementation to typecast the object return value from
6643         ///   get_Current into the proper type.  All code has been generated and
6644         ///   we only care about the side effect conversions to be performed
6645         ///
6646         ///   This is also now used as a placeholder where a no-action expression
6647         ///   is needed (the `New' class).
6648         /// </summary>
6649         public class EmptyExpression : Expression {
6650                 public EmptyExpression ()
6651                 {
6652                         type = TypeManager.object_type;
6653                         eclass = ExprClass.Value;
6654                         loc = Location.Null;
6655                 }
6656
6657                 public EmptyExpression (Type t)
6658                 {
6659                         type = t;
6660                         eclass = ExprClass.Value;
6661                         loc = Location.Null;
6662                 }
6663
6664                 public override Expression DoResolve (EmitContext ec)
6665                 {
6666                         return this;
6667                 }
6668
6669                 public override void Emit (EmitContext ec)
6670                 {
6671                         // nothing, as we only exist to not do anything.
6672                 }
6673
6674                 //
6675                 // This is just because we might want to reuse this bad boy
6676                 // instead of creating gazillions of EmptyExpressions.
6677                 // (CanConvertImplicit uses it)
6678                 //
6679                 public void SetType (Type t)
6680                 {
6681                         type = t;
6682                 }
6683         }
6684
6685         public class UserCast : Expression {
6686                 MethodBase method;
6687                 Expression source;
6688
6689                 public UserCast (MethodInfo method, Expression source, Location l)
6690                 {
6691                         this.method = method;
6692                         this.source = source;
6693                         type = method.ReturnType;
6694                         eclass = ExprClass.Value;
6695                         loc = l;
6696                 }
6697
6698                 public override Expression DoResolve (EmitContext ec)
6699                 {
6700                         //
6701                         // We are born fully resolved
6702                         //
6703                         return this;
6704                 }
6705
6706                 public override void Emit (EmitContext ec)
6707                 {
6708                         ILGenerator ig = ec.ig;
6709
6710                         source.Emit (ec);
6711
6712                         if (method is MethodInfo)
6713                                 ig.Emit (OpCodes.Call, (MethodInfo) method);
6714                         else
6715                                 ig.Emit (OpCodes.Call, (ConstructorInfo) method);
6716
6717                 }
6718         }
6719
6720         // <summary>
6721         //   This class is used to "construct" the type during a typecast
6722         //   operation.  Since the Type.GetType class in .NET can parse
6723         //   the type specification, we just use this to construct the type
6724         //   one bit at a time.
6725         // </summary>
6726         public class ComposedCast : Expression, ITypeExpression {
6727                 Expression left;
6728                 string dim;
6729
6730                 public ComposedCast (Expression left, string dim, Location l)
6731                 {
6732                         this.left = left;
6733                         this.dim = dim;
6734                         loc = l;
6735                 }
6736
6737                 public Expression DoResolveType (EmitContext ec)
6738                 {
6739                         Type ltype = ec.DeclSpace.ResolveType (left, false, loc);
6740                         if (ltype == null)
6741                                 return null;
6742
6743                         //
6744                         // ltype.Fullname is already fully qualified, so we can skip
6745                         // a lot of probes, and go directly to TypeManager.LookupType
6746                         //
6747                         string cname = ltype.FullName + dim;
6748                         type = TypeManager.LookupTypeDirect (cname);
6749                         if (type == null){
6750                                 //
6751                                 // For arrays of enumerations we are having a problem
6752                                 // with the direct lookup.  Need to investigate.
6753                                 //
6754                                 // For now, fall back to the full lookup in that case.
6755                                 //
6756                                 type = RootContext.LookupType (
6757                                         ec.DeclSpace, cname, false, loc);
6758
6759                                 if (type == null)
6760                                         return null;
6761                         }
6762
6763                         if (!ec.ResolvingTypeTree){
6764                                 //
6765                                 // If the above flag is set, this is being invoked from the ResolveType function.
6766                                 // Upper layers take care of the type validity in this context.
6767                                 //
6768                         if (!ec.InUnsafe && type.IsPointer){
6769                                 UnsafeError (loc);
6770                                 return null;
6771                         }
6772                         }
6773
6774                         eclass = ExprClass.Type;
6775                         return this;
6776                 }
6777
6778                 public override Expression DoResolve (EmitContext ec)
6779                 {
6780                         return DoResolveType (ec);
6781                 }
6782
6783                 public override void Emit (EmitContext ec)
6784                 {
6785                         throw new Exception ("This should never be called");
6786                 }
6787
6788                 public override string ToString ()
6789                 {
6790                         return left + dim;
6791                 }
6792         }
6793
6794         //
6795         // This class is used to represent the address of an array, used
6796         // only by the Fixed statement, this is like the C "&a [0]" construct.
6797         //
6798         public class ArrayPtr : Expression {
6799                 Expression array;
6800
6801                 public ArrayPtr (Expression array, Location l)
6802                 {
6803                         Type array_type = array.Type.GetElementType ();
6804
6805                         this.array = array;
6806
6807                         string array_ptr_type_name = array_type.FullName + "*";
6808
6809                         type = Type.GetType (array_ptr_type_name);
6810                         if (type == null){
6811                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
6812
6813                                 type = mb.GetType (array_ptr_type_name);
6814                         }
6815
6816                         eclass = ExprClass.Value;
6817                         loc = l;
6818                 }
6819
6820                 public override void Emit (EmitContext ec)
6821                 {
6822                         ILGenerator ig = ec.ig;
6823
6824                         array.Emit (ec);
6825                         IntLiteral.EmitInt (ig, 0);
6826                         ig.Emit (OpCodes.Ldelema, array.Type.GetElementType ());
6827                 }
6828
6829                 public override Expression DoResolve (EmitContext ec)
6830                 {
6831                         //
6832                         // We are born fully resolved
6833                         //
6834                         return this;
6835                 }
6836         }
6837
6838         //
6839         // Used by the fixed statement
6840         //
6841         public class StringPtr : Expression {
6842                 LocalBuilder b;
6843
6844                 public StringPtr (LocalBuilder b, Location l)
6845                 {
6846                         this.b = b;
6847                         eclass = ExprClass.Value;
6848                         type = TypeManager.char_ptr_type;
6849                         loc = l;
6850                 }
6851
6852                 public override Expression DoResolve (EmitContext ec)
6853                 {
6854                         // This should never be invoked, we are born in fully
6855                         // initialized state.
6856
6857                         return this;
6858                 }
6859
6860                 public override void Emit (EmitContext ec)
6861                 {
6862                         ILGenerator ig = ec.ig;
6863
6864                         ig.Emit (OpCodes.Ldloc, b);
6865                         ig.Emit (OpCodes.Conv_I);
6866                         ig.Emit (OpCodes.Call, TypeManager.int_get_offset_to_string_data);
6867                         ig.Emit (OpCodes.Add);
6868                 }
6869         }
6870
6871         //
6872         // Implements the `stackalloc' keyword
6873         //
6874         public class StackAlloc : Expression {
6875                 Type otype;
6876                 Expression t;
6877                 Expression count;
6878
6879                 public StackAlloc (Expression type, Expression count, Location l)
6880                 {
6881                         t = type;
6882                         this.count = count;
6883                         loc = l;
6884                 }
6885
6886                 public override Expression DoResolve (EmitContext ec)
6887                 {
6888                         count = count.Resolve (ec);
6889                         if (count == null)
6890                                 return null;
6891
6892                         if (count.Type != TypeManager.int32_type){
6893                                 count = ConvertImplicitRequired (ec, count, TypeManager.int32_type, loc);
6894                                 if (count == null)
6895                                         return null;
6896                         }
6897
6898                         if (ec.InCatch || ec.InFinally){
6899                                 Error (255,
6900                                               "stackalloc can not be used in a catch or finally block");
6901                                 return null;
6902                         }
6903
6904                         otype = ec.DeclSpace.ResolveType (t, false, loc);
6905
6906                         if (otype == null)
6907                                 return null;
6908
6909                         if (!TypeManager.VerifyUnManaged (otype, loc))
6910                                 return null;
6911
6912                         string ptr_name = otype.FullName + "*";
6913                         type = Type.GetType (ptr_name);
6914                         if (type == null){
6915                                 ModuleBuilder mb = CodeGen.ModuleBuilder;
6916
6917                                 type = mb.GetType (ptr_name);
6918                         }
6919                         eclass = ExprClass.Value;
6920
6921                         return this;
6922                 }
6923
6924                 public override void Emit (EmitContext ec)
6925                 {
6926                         int size = GetTypeSize (otype);
6927                         ILGenerator ig = ec.ig;
6928
6929                         if (size == 0)
6930                                 ig.Emit (OpCodes.Sizeof, otype);
6931                         else
6932                                 IntConstant.EmitInt (ig, size);
6933                         count.Emit (ec);
6934                         ig.Emit (OpCodes.Mul);
6935                         ig.Emit (OpCodes.Localloc);
6936                 }
6937         }
6938 }