mcs/mbas/delegate.cs

   1 //
   2 // delegate.cs: Delegate Handler
   3 //
   4 // Author: Ravi Pratap (ravi@ximian.com)
   5 //
   6 // Licensed under the terms of the GNU GPL
   7 //
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)
   9 //
  10 //
  11
  12 using System;
  13 using System.Collections;
  14 using System.Reflection;
  15 using System.Reflection.Emit;
  16 using System.Text;
  17
  18 namespace Mono.MonoBASIC {
  19
  20         /// <summary>
  21         ///   Holds Delegates
  22         /// </summary>
  23         public class Delegate : DeclSpace {
  24                 public Expression ReturnType;
  25                 public Parameters      Parameters;
  26
  27                 public ConstructorBuilder ConstructorBuilder;
  28                 public MethodBuilder      InvokeBuilder;
  29                 public MethodBuilder      BeginInvokeBuilder;
  30                 public MethodBuilder      EndInvokeBuilder;
  31
  32                 Type [] param_types;
  33                 Type ret_type;
  34
  35                 Expression instance_expr;
  36                 MethodBase delegate_method;
  37
  38                 const int AllowedModifiers =
  39                         Modifiers.SHADOWS |
  40                         Modifiers.PUBLIC |
  41                         Modifiers.PROTECTED |
  42                         Modifiers.INTERNAL |
  43                     Modifiers.UNSAFE |
  44                         Modifiers.PRIVATE;
  45
  46                 public Delegate (TypeContainer parent, Expression type, int mod_flags,
  47                                  string name, Parameters param_list,
  48                                  Attributes attrs, Location l)
  49                         : base (parent, name, attrs, l)
  50                 {
  51                         this.ReturnType = type;
  52
  53                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  54                                                            IsTopLevel ? Modifiers.INTERNAL :
  55                                                            Modifiers.PUBLIC, l);
  56                         Parameters      = param_list;
  57                 }
  58
  59                 public override AttributeTargets AttributeTargets {
  60                         get {
  61                                 return AttributeTargets.Delegate;
  62                         }
  63                 }
  64
  65                 public override TypeBuilder DefineType ()
  66                 {
  67                         TypeAttributes attr;
  68
  69                         if (TypeBuilder != null)
  70                                 return TypeBuilder;
  71
  72                         if (IsTopLevel) {
  73                                 ModuleBuilder builder = CodeGen.ModuleBuilder;
  74                                 attr = TypeAttributes.Public | TypeAttributes.Class | TypeAttributes.Sealed;
  75
  76                                 TypeBuilder = builder.DefineType (
  77                                         Name, attr, TypeManager.multicast_delegate_type);
  78                         } else {
  79                                 TypeBuilder builder = Parent.TypeBuilder;
  80                                 attr = TypeAttributes.NestedPublic | TypeAttributes.Class |
  81                                         TypeAttributes.Sealed;
  82
  83                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
  84                                 TypeBuilder = builder.DefineNestedType (
  85                                         name, attr, TypeManager.multicast_delegate_type);
  86                         }
  87
  88                         TypeManager.AddDelegateType (Name, TypeBuilder, this);
  89
  90                         return TypeBuilder;
  91                 }
  92
  93                 public override bool DefineMembers (TypeContainer container)
  94                 {
  95                         return true;
  96                 }
  97
  98                 public override bool Define (TypeContainer container)
  99                 {
 100                         MethodAttributes mattr;
 101                         int i;
 102
 103                         // FIXME: POSSIBLY make this static, as it is always constant
 104                         //
 105                         Type [] const_arg_types = new Type [2];
 106                         const_arg_types [0] = TypeManager.object_type;
 107                         const_arg_types [1] = TypeManager.intptr_type;
 108
 109                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 110                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 111
 112                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 113                                                                             CallingConventions.Standard,
 114                                                                             const_arg_types);
 115
 116                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 117                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 118                         //
 119                         // HACK because System.Reflection.Emit is lame
 120                         //
 121                         //
 122                         // FIXME: POSSIBLY make these static, as they are always the same
 123                         Parameter [] fixed_pars = new Parameter [2];
 124                         fixed_pars [0] = new Parameter (null, null, Parameter.Modifier.NONE, null);
 125                         fixed_pars [1] = new Parameter (null, null, Parameter.Modifier.NONE, null);
 126                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);
 127
 128                         TypeManager.RegisterMethod (
 129                                 ConstructorBuilder,
 130                                 new InternalParameters (const_arg_types, const_parameters),
 131                                 const_arg_types);
 132
 133
 134                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 135
 136                         //
 137                         // Here the various methods like Invoke, BeginInvoke etc are defined
 138                         //
 139                         // First, call the `out of band' special method for
 140                         // defining recursively any types we need:
 141
 142                         if (!Parameters.ComputeAndDefineParameterTypes (this))
 143                                 return false;
 144
 145                         param_types = Parameters.GetParameterInfo (this);
 146                         if (param_types == null)
 147                                 return false;
 148
 149                         //
 150                         // Invoke method
 151                         //
 152
 153                         // Check accessibility
 154                         foreach (Type partype in param_types)
 155                                 if (!container.AsAccessible (partype, ModFlags)) {
 156                                         Report.Error (59, Location,
 157                                                       "Inconsistent accessibility: parameter type `" +
 158                                                       TypeManager.MonoBASIC_Name (partype) + "` is less " +
 159                                                       "accessible than delegate `" + Name + "'");
 160                                         return false;
 161                                 }
 162
 163                         ReturnType = ResolveTypeExpr (ReturnType, false, Location);
 164                         ret_type = ReturnType.Type;
 165                         if (ret_type == null)
 166                                 return false;
 167
 168                         if (!container.AsAccessible (ret_type, ModFlags)) {
 169                                 Report.Error (58, Location,
 170                                               "Inconsistent accessibility: return type `" +
 171                                               TypeManager.MonoBASIC_Name (ret_type) + "` is less " +
 172                                               "accessible than delegate `" + Name + "'");
 173                                 return false;
 174                         }
 175
 176                         //
 177                         // We don't have to check any others because they are all
 178                         // guaranteed to be accessible - they are standard types.
 179                         //
 180
 181                         CallingConventions cc = Parameters.GetCallingConvention ();
 182
 183                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 184
 185                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 186                                                                   mattr,
 187                                                                   cc,
 188                                                                   ret_type,
 189                                                                   param_types);
 190
 191                         i = 0;
 192                         if (Parameters.FixedParameters != null){
 193                                 int top = Parameters.FixedParameters.Length;
 194                                 Parameter p;
 195
 196                                 for (; i < top; i++) {
 197                                         p = Parameters.FixedParameters [i];
 198
 199                                         InvokeBuilder.DefineParameter (
 200                                                 i+1, p.Attributes, p.Name);
 201                                 }
 202                         }
 203                         if (Parameters.ArrayParameter != null){
 204                                 Parameter p = Parameters.ArrayParameter;
 205
 206                                 InvokeBuilder.DefineParameter (
 207                                         i+1, p.Attributes, p.Name);
 208                         }
 209
 210                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 211
 212                         TypeManager.RegisterMethod (InvokeBuilder,
 213                                                     new InternalParameters (container, Parameters),
 214                                                     param_types);
 215
 216                         //
 217                         // BeginInvoke
 218                         //
 219                         int params_num = param_types.Length;
 220                         Type [] async_param_types = new Type [params_num + 2];
 221
 222                         param_types.CopyTo (async_param_types, 0);
 223
 224                         async_param_types [params_num] = TypeManager.asynccallback_type;
 225                         async_param_types [params_num + 1] = TypeManager.object_type;
 226
 227                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 228                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 229
 230                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 231                                                                        mattr,
 232                                                                        cc,
 233                                                                        TypeManager.iasyncresult_type,
 234                                                                        async_param_types);
 235
 236                         i = 0;
 237                         if (Parameters.FixedParameters != null){
 238                                 int top = Parameters.FixedParameters.Length;
 239                                 Parameter p;
 240
 241                                 for (i = 0 ; i < top; i++) {
 242                                         p = Parameters.FixedParameters [i];
 243
 244                                         BeginInvokeBuilder.DefineParameter (
 245                                                 i+1, p.Attributes, p.Name);
 246                                 }
 247                         }
 248                         if (Parameters.ArrayParameter != null){
 249                                 Parameter p = Parameters.ArrayParameter;
 250
 251                                 BeginInvokeBuilder.DefineParameter (
 252                                         i+1, p.Attributes, p.Name);
 253                                 i++;
 254                         }
 255
 256                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 257                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 258
 259                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 260
 261                         Parameter [] async_params = new Parameter [params_num + 2];
 262                         int n = 0;
 263                         if (Parameters.FixedParameters != null){
 264                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 265                                 n = Parameters.FixedParameters.Length;
 266                         }
 267                         if (Parameters.ArrayParameter != null)
 268                                 async_params [n] = Parameters.ArrayParameter;
 269
 270                         async_params [params_num] = new Parameter (
 271                                 TypeManager.system_asynccallback_expr, "callback",
 272                                                                    Parameter.Modifier.NONE, null);
 273                         async_params [params_num + 1] = new Parameter (
 274                                 TypeManager.system_object_expr, "object",
 275                                                                    Parameter.Modifier.NONE, null);
 276
 277                         Parameters async_parameters = new Parameters (async_params, null, Location);
 278
 279                         async_parameters.ComputeAndDefineParameterTypes (this);
 280                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 281                                                     new InternalParameters (container, async_parameters),
 282                                                     async_param_types);
 283
 284                         //
 285                         // EndInvoke
 286                         //
 287                         Type [] end_param_types = new Type [1];
 288                         end_param_types [0] = TypeManager.iasyncresult_type;
 289
 290                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke",
 291                                                                      mattr,
 292                                                                      cc,
 293                                                                      ret_type,
 294                                                                      end_param_types);
 295                         EndInvokeBuilder.DefineParameter (1, ParameterAttributes.None, "result");
 296
 297                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 298
 299                         Parameter [] end_params = new Parameter [1];
 300                         end_params [0] = new Parameter (
 301                                 TypeManager.system_iasyncresult_expr, "result",
 302                                                         Parameter.Modifier.NONE, null);
 303
 304                         TypeManager.RegisterMethod (
 305                                 EndInvokeBuilder, new InternalParameters (
 306                                         container,
 307                                         new Parameters (
 308                                                 end_params, null, Location)),
 309                                                     end_param_types);
 310
 311                         return true;
 312                 }
 313
 314                 /// <summary>
 315                 ///  Verifies whether the method in question is compatible with the delegate
 316                 ///  Returns the method itself if okay and null if not.
 317                 /// </summary>
 318                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 319                                                        Location loc)
 320                 {
 321                         ParameterData pd = Invocation.GetParameterData (mb);
 322
 323                         int pd_count = pd.Count;
 324
 325                         Expression ml = Expression.MemberLookup (
 326                                 ec, delegate_type, "Invoke", loc);
 327
 328                         if (!(ml is MethodGroupExpr)) {
 329                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 330                                 return null;
 331                         }
 332
 333                         MethodBase invoke_mb = ((MethodGroupExpr) ml).Methods [0];
 334
 335                         ParameterData invoke_pd = Invocation.GetParameterData (invoke_mb);
 336
 337                         if (invoke_pd.Count != pd_count)
 338                                 return null;
 339
 340                         for (int i = pd_count; i > 0; ) {
 341                                 i--;
 342
 343                                 if (invoke_pd.ParameterType (i) == pd.ParameterType (i))
 344                                         continue;
 345                                 else
 346                                         return null;
 347                         }
 348
 349                         if (((MethodInfo) invoke_mb).ReturnType == ((MethodInfo) mb).ReturnType)
 350                                 return mb;
 351                         else
 352                                 return null;
 353                 }
 354
 355                 // <summary>
 356                 //  Verifies whether the invocation arguments are compatible with the
 357                 //  delegate's target method
 358                 // </summary>
 359                 public static bool VerifyApplicability (EmitContext ec,
 360                                                         Type delegate_type,
 361                                                         ArrayList args,
 362                                                         Location loc)
 363                 {
 364                         int arg_count;
 365
 366                         if (args == null)
 367                                 arg_count = 0;
 368                         else
 369                                 arg_count = args.Count;
 370
 371                         Expression ml = Expression.MemberLookup (
 372                                 ec, delegate_type, "Invoke", loc);
 373
 374                         if (!(ml is MethodGroupExpr)) {
 375                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 376                                 return false;
 377                         }
 378
 379                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 380                         ParameterData pd = Invocation.GetParameterData (mb);
 381
 382                         int pd_count = pd.Count;
 383
 384                         bool not_params_method = (pd_count == 0) ||
 385                                 (pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS);
 386
 387                         if (not_params_method && pd_count != arg_count) {
 388                                 Report.Error (1593, loc,
 389                                               "Delegate '" + delegate_type.ToString ()
 390                                               + "' does not take '" + arg_count + "' arguments");
 391                                 return false;
 392                         }
 393
 394                         return Invocation.VerifyArgumentsCompat (ec, args, arg_count, mb, !not_params_method,
 395                                                                  delegate_type, loc);
 396                 }
 397
 398                 /// <summary>
 399                 ///  Verifies whether the delegate in question is compatible with this one in
 400                 ///  order to determine if instantiation from the same is possible.
 401                 /// </summary>
 402                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 403                 {
 404                         Expression ml = Expression.MemberLookup (
 405                                 ec, delegate_type, "Invoke", loc);
 406
 407                         if (!(ml is MethodGroupExpr)) {
 408                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 409                                 return false;
 410                         }
 411
 412                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 413                         ParameterData pd = Invocation.GetParameterData (mb);
 414
 415                         Expression probe_ml = Expression.MemberLookup (
 416                                 ec, delegate_type, "Invoke", loc);
 417
 418                         if (!(probe_ml is MethodGroupExpr)) {
 419                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 420                                 return false;
 421                         }
 422
 423                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 424                         ParameterData probe_pd = Invocation.GetParameterData (probe_mb);
 425
 426                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 427                                 return false;
 428
 429                         if (pd.Count != probe_pd.Count)
 430                                 return false;
 431
 432                         for (int i = pd.Count; i > 0; ) {
 433                                 i--;
 434
 435                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 436                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 437                                         return false;
 438                         }
 439
 440                         return true;
 441                 }
 442
 443                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 444                 {
 445                         StringBuilder sb = new StringBuilder (TypeManager.MonoBASIC_Name (((MethodInfo) mb).ReturnType));
 446
 447                         sb.Append (" " + del_type.ToString ());
 448                         sb.Append (" (");
 449
 450                         int length = pd.Count;
 451
 452                         for (int i = length; i > 0; ) {
 453                                 i--;
 454
 455                                 sb.Append (TypeManager.MonoBASIC_Name (pd.ParameterType (length - i - 1)));
 456                                 if (i != 0)
 457                                         sb.Append (", ");
 458                         }
 459
 460                         sb.Append (")");
 461                         return sb.ToString ();
 462
 463                 }
 464
 465                 // Hack around System.Reflection as found everywhere else
 466                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 467                                                         MemberFilter filter, object criteria)
 468                 {
 469                         ArrayList members = new ArrayList ();
 470
 471                         if ((mt & MemberTypes.Method) != 0) {
 472                                 if (ConstructorBuilder != null)
 473                                 if (filter (ConstructorBuilder, criteria))
 474                                         members.Add (ConstructorBuilder);
 475
 476                                 if (InvokeBuilder != null)
 477                                 if (filter (InvokeBuilder, criteria))
 478                                         members.Add (InvokeBuilder);
 479
 480                                 if (BeginInvokeBuilder != null)
 481                                 if (filter (BeginInvokeBuilder, criteria))
 482                                         members.Add (BeginInvokeBuilder);
 483
 484                                 if (EndInvokeBuilder != null)
 485                                 if (filter (EndInvokeBuilder, criteria))
 486                                         members.Add (EndInvokeBuilder);
 487                         }
 488
 489                         return new MemberList (members);
 490                 }
 491
 492                 public override MemberCache MemberCache {
 493                         get {
 494                                 return null;
 495                         }
 496                 }
 497
 498                 public Expression InstanceExpression {
 499                         get {
 500                                 return instance_expr;
 501                         }
 502                         set {
 503                                 instance_expr = value;
 504                         }
 505                 }
 506
 507                 public MethodBase TargetMethod {
 508                         get {
 509                                 return delegate_method;
 510                         }
 511                         set {
 512                                 delegate_method = value;
 513                         }
 514                 }
 515
 516                 public Type TargetReturnType {
 517                         get {
 518                                 return ret_type;
 519                         }
 520                 }
 521
 522                 public Type [] ParameterTypes {
 523                         get {
 524                                 return param_types;
 525                         }
 526                 }
 527
 528         }
 529
 530         public class NewDelegate : Expression {
 531
 532                 public ArrayList Arguments;
 533
 534                 MethodBase constructor_method;
 535                 MethodBase delegate_method;
 536                 Expression delegate_instance_expr;
 537
 538                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 539                 {
 540                         this.type = type;
 541                         this.Arguments = Arguments;
 542                         this.loc  = loc;
 543                 }
 544
 545                 public override Expression DoResolve (EmitContext ec)
 546                 {
 547                         if (Arguments == null) {
 548                                 Report.Error (-11, loc,
 549                                               "Delegate creation expression takes only one argument");
 550                                 return null;
 551                         }
 552
 553                         if (Arguments.Count != 1) {
 554                                 Report.Error (-11, loc,
 555                                               "Delegate creation expression takes only one argument");
 556                                 return null;
 557                         }
 558
 559                         Expression ml = Expression.MemberLookup (
 560                                 ec, type, ".ctor", loc);
 561
 562                         if (!(ml is MethodGroupExpr)) {
 563                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 564                                 return null;
 565                         }
 566
 567                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 568                         Argument a = (Argument) Arguments [0];
 569
 570                         if (!a.ResolveMethodGroup (ec, Location))
 571                                 return null;
 572
 573                         Expression e = a.Expr;
 574
 575                         Expression invoke_method = Expression.MemberLookup (
 576                                 ec, type, "Invoke", MemberTypes.Method,
 577                                 Expression.AllBindingFlags, loc);
 578
 579                         if (invoke_method == null) {
 580                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 581                                 return null;
 582                         }
 583
 584                         if (e is MethodGroupExpr) {
 585                                 MethodGroupExpr mg = (MethodGroupExpr) e;
 586
 587                                 foreach (MethodInfo mi in mg.Methods){
 588                                         delegate_method  = Delegate.VerifyMethod (ec, type, mi, loc);
 589
 590                                         if (delegate_method != null)
 591                                                 break;
 592                                 }
 593
 594                                 if (delegate_method == null) {
 595                                         string method_desc;
 596                                         if (mg.Methods.Length > 1)
 597                                                 method_desc = mg.Methods [0].Name;
 598                                         else
 599                                                 method_desc = Invocation.FullMethodDesc (mg.Methods [0]);
 600
 601                                         MethodBase dm = ((MethodGroupExpr) invoke_method).Methods [0];
 602                                         ParameterData param = Invocation.GetParameterData (dm);
 603                                         string delegate_desc = Delegate.FullDelegateDesc (type, dm, param);
 604
 605                                         Report.Error (30408, loc, "Method '" + method_desc + "' does not " +
 606                                                       "match delegate '" + delegate_desc + "'");
 607
 608                                         return null;
 609                                 }
 610
 611                                 //
 612                                 // Check safe/unsafe of the delegate
 613                                 //
 614                                 if (!ec.InUnsafe){
 615                                         ParameterData param = Invocation.GetParameterData (delegate_method);
 616                                         int count = param.Count;
 617
 618                                         for (int i = 0; i < count; i++){
 619                                                 if (param.ParameterType (i).IsPointer){
 620                                                         Expression.UnsafeError (loc);
 621                                                         return null;
 622                                                 }
 623                                         }
 624                                 }
 625
 626                                 if (mg.InstanceExpression != null)
 627                                         delegate_instance_expr = mg.InstanceExpression.Resolve (ec);
 628                                 else {
 629                                         if (!ec.IsStatic)
 630                                                 delegate_instance_expr = ec.This;
 631                                         else
 632                                                 delegate_instance_expr = null;
 633                                 }
 634
 635                                 if (delegate_instance_expr != null)
 636                                         if (delegate_instance_expr.Type.IsValueType)
 637                                                 delegate_instance_expr = new BoxedCast (delegate_instance_expr);
 638
 639                                 eclass = ExprClass.Value;
 640                                 return this;
 641                         }
 642
 643                         Type e_type = e.Type;
 644
 645                         if (!TypeManager.IsDelegateType (e_type)) {
 646                                 Report.Error (-12, loc, "Cannot create a delegate from something " +
 647                                               "not a delegate or a method.");
 648                                 return null;
 649                         }
 650
 651                         // This is what MS' compiler reports. We could always choose
 652                         // to be more verbose and actually give delegate-level specifics
 653
 654                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 655                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 656                                               "to type '" + type + "'");
 657                                 return null;
 658                         }
 659
 660                         delegate_instance_expr = e;
 661                         delegate_method = ((MethodGroupExpr) invoke_method).Methods [0];
 662
 663                         eclass = ExprClass.Value;
 664                         return this;
 665                 }
 666
 667                 public override void Emit (EmitContext ec)
 668                 {
 669                         if (delegate_instance_expr == null ||
 670                             delegate_method.IsStatic)
 671                                 ec.ig.Emit (OpCodes.Ldnull);
 672                         else
 673                                 delegate_instance_expr.Emit (ec);
 674
 675                         if (delegate_method.IsVirtual) {
 676                                 ec.ig.Emit (OpCodes.Dup);
 677                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 678                         } else
 679                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 680                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 681                 }
 682         }
 683
 684         public class DelegateInvocation : ExpressionStatement {
 685
 686                 public Expression InstanceExpr;
 687                 public ArrayList  Arguments;
 688
 689                 MethodBase method;
 690
 691                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 692                 {
 693                         this.InstanceExpr = instance_expr;
 694                         this.Arguments = args;
 695                         this.loc = loc;
 696                 }
 697
 698                 public override Expression DoResolve (EmitContext ec)
 699                 {
 700                         if (InstanceExpr is EventExpr) {
 701
 702                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 703
 704                                 Expression ml = MemberLookup (
 705                                         ec, ec.ContainerType, ei.Name,
 706                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 707
 708                                 if (ml == null) {
 709                                         //
 710                                         // If this is the case, then the Event does not belong
 711                                         // to this Type and so, according to the spec
 712                                         // cannot be accessed directly
 713                                         //
 714                                         // Note that target will not appear as an EventExpr
 715                                         // in the case it is being referenced within the same type container;
 716                                         // it will appear as a FieldExpr in that case.
 717                                         //
 718
 719                                         Assign.error70 (ei, loc);
 720                                         return null;
 721                                 }
 722                         }
 723
 724
 725                         Type del_type = InstanceExpr.Type;
 726                         if (del_type == null)
 727                                 return null;
 728
 729                         if (Arguments != null){
 730                                 foreach (Argument a in Arguments){
 731                                         if (!a.Resolve (ec, loc))
 732                                                 return null;
 733                                 }
 734                         }
 735
 736                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 737                                 return null;
 738
 739                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
 740                         if (!(lookup is MethodGroupExpr)) {
 741                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 742                                 return null;
 743                         }
 744
 745                         method = ((MethodGroupExpr) lookup).Methods [0];
 746                         type = ((MethodInfo) method).ReturnType;
 747                         eclass = ExprClass.Value;
 748
 749                         return this;
 750                 }
 751
 752                 public override void Emit (EmitContext ec)
 753                 {
 754                         Delegate del = TypeManager.LookupDelegate (InstanceExpr.Type);
 755
 756                         //
 757                         // Invocation on delegates call the virtual Invoke member
 758                         // so we are always `instance' calls
 759                         //
 760                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
 761                 }
 762
 763                 public override void EmitStatement (EmitContext ec)
 764                 {
 765                         Emit (ec);
 766                         //
 767                         // Pop the return value if there is one
 768                         //
 769                         if (method is MethodInfo){
 770                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
 771                                         ec.ig.Emit (OpCodes.Pop);
 772                         }
 773                 }
 774
 775         }
 776 }