mcs/mcs/delegate.cs

   1 //\r
   2 // delegate.cs: Delegate Handler\r
   3 //\r
   4 // Author: Ravi Pratap (ravi@ximian.com)\r
   5 //\r
   6 // Licensed under the terms of the GNU GPL\r
   7 //\r
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)\r
   9 //\r
  10 //\r
  11 \r
  12 using System;\r
  13 using System.Collections;\r
  14 using System.Reflection;\r
  15 using System.Reflection.Emit;\r
  16 using System.Text;\r
  17 \r
  18 namespace Mono.CSharp {\r
  19 \r
  20         /// <summary>\r
  21         ///   Holds Delegates\r
  22         /// </summary>\r
  23         public class Delegate : MemberCore {\r
  24                 public readonly string ReturnType;\r
  25                 public Parameters      Parameters;\r
  26                 public Attributes      OptAttributes;\r
  27                 public TypeBuilder     TypeBuilder;\r
  28 \r
  29                 public ConstructorBuilder ConstructorBuilder;\r
  30                 public MethodBuilder      InvokeBuilder;\r
  31                 public MethodBuilder      BeginInvokeBuilder;\r
  32                 public MethodBuilder      EndInvokeBuilder;\r
  33                 \r
  34                 Type [] param_types;\r
  35                 Type ret_type;\r
  36                 \r
  37                 Expression instance_expr;\r
  38                 MethodBase delegate_method;\r
  39         \r
  40                 const int AllowedModifiers =\r
  41                         Modifiers.NEW |\r
  42                         Modifiers.PUBLIC |\r
  43                         Modifiers.PROTECTED |\r
  44                         Modifiers.INTERNAL |\r
  45                         Modifiers.UNSAFE |\r
  46                         Modifiers.PRIVATE;\r
  47 \r
  48                 public Delegate (string type, int mod_flags, string name, Parameters param_list,\r
  49                                  Attributes attrs, Location l)\r
  50                         : base (name, l)\r
  51                 {\r
  52                         this.ReturnType = type;\r
  53                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags, Modifiers.PUBLIC, l);\r
  54                         Parameters      = param_list;\r
  55                         OptAttributes   = attrs;\r
  56                 }\r
  57 \r
  58                 public void DefineDelegate (object parent_builder)\r
  59                 {\r
  60                         TypeAttributes attr;\r
  61 \r
  62                         if (TypeBuilder != null)\r
  63                                 return;\r
  64                         \r
  65                         string name = Name.Substring (1 + Name.LastIndexOf ('.'));\r
  66 \r
  67                         if (parent_builder is ModuleBuilder) {\r
  68                                 ModuleBuilder builder = (ModuleBuilder) parent_builder;\r
  69                                 attr = TypeAttributes.Public | TypeAttributes.Class | TypeAttributes.Sealed;\r
  70 \r
  71                                 TypeBuilder = builder.DefineType (\r
  72                                         name, attr, TypeManager.multicast_delegate_type);\r
  73                         } else {\r
  74                                 // FIXME: We could just use TypeBuilder here.\r
  75                                 TypeBuilder builder = (System.Reflection.Emit.TypeBuilder) parent_builder;\r
  76                                 attr = TypeAttributes.NestedPublic | TypeAttributes.Class |\r
  77                                         TypeAttributes.Sealed;\r
  78 \r
  79                                 TypeBuilder = builder.DefineNestedType (\r
  80                                         name, attr, TypeManager.multicast_delegate_type);\r
  81                         }\r
  82 \r
  83                         TypeManager.AddDelegateType (Name, TypeBuilder, this);\r
  84                 }\r
  85 \r
  86                 public override bool Define (TypeContainer parent)\r
  87                 {\r
  88                         MethodAttributes mattr;\r
  89                         int i;\r
  90                         \r
  91                         // FIXME: POSSIBLY make this static, as it is always constant\r
  92                         // \r
  93                         Type [] const_arg_types = new Type [2];\r
  94                         const_arg_types [0] = TypeManager.object_type;\r
  95                         const_arg_types [1] = TypeManager.intptr_type;\r
  96 \r
  97                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |\r
  98                                 MethodAttributes.HideBySig | MethodAttributes.Public;\r
  99 \r
 100                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,\r
 101                                                                             CallingConventions.Standard,\r
 102                                                                             const_arg_types);\r
 103 \r
 104                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");\r
 105                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");\r
 106                         //\r
 107                         // HACK because System.Reflection.Emit is lame\r
 108                         //\r
 109                         //\r
 110                         // FIXME: POSSIBLY make these static, as they are always the same\r
 111                         Parameter [] fixed_pars = new Parameter [2];\r
 112                         fixed_pars [0] = new Parameter (null, null, Parameter.Modifier.NONE, null);\r
 113                         fixed_pars [1] = new Parameter (null, null, Parameter.Modifier.NONE, null);\r
 114                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);\r
 115                         \r
 116                         TypeManager.RegisterMethod (\r
 117                                 ConstructorBuilder,\r
 118                                 new InternalParameters (const_arg_types, const_parameters),\r
 119                                 const_arg_types);\r
 120                                 \r
 121                         \r
 122                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);\r
 123                         \r
 124                         // Here the various methods like Invoke, BeginInvoke etc are defined\r
 125 \r
 126                         //\r
 127                         // Invoke method\r
 128                         //\r
 129                         param_types = Parameters.GetParameterInfo (parent);\r
 130                         if (param_types == null)\r
 131                                 return false;\r
 132 \r
 133                         // Check accessibility\r
 134                         foreach (Type partype in param_types)\r
 135                                 if (!TypeContainer.AsAccessible (partype, ModFlags))\r
 136                                         return false;\r
 137                         \r
 138                         ret_type = RootContext.LookupType (parent, ReturnType, false, Location);\r
 139                         if (ret_type == null)\r
 140                                 return false;\r
 141 \r
 142                         if (!TypeContainer.AsAccessible (ret_type, ModFlags))\r
 143                                 return false;\r
 144 \r
 145                         //\r
 146                         // We don't have to check any others because they are all\r
 147                         // guaranteed to be accessible - they are standard types.\r
 148                         //\r
 149                         \r
 150                         CallingConventions cc = Parameters.GetCallingConvention ();\r
 151 \r
 152                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;\r
 153 \r
 154                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke", \r
 155                                                                   mattr,                     \r
 156                                                                   cc,\r
 157                                                                   ret_type,                  \r
 158                                                                   param_types);\r
 159 \r
 160                         for (i = 0 ; i < param_types.Length; i++) {\r
 161                                 Parameter p = Parameters.FixedParameters [i];\r
 162                                 string name = p.Name;\r
 163                                 ParameterBuilder pb = InvokeBuilder.DefineParameter (i+1, p.Attributes, name); \r
 164                         }\r
 165                         \r
 166                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);\r
 167 \r
 168                         TypeManager.RegisterMethod (InvokeBuilder,\r
 169                                                     new InternalParameters (parent, Parameters),\r
 170                                                     param_types);\r
 171 \r
 172                         //\r
 173                         // BeginInvoke\r
 174                         //\r
 175                         int params_num = param_types.Length;\r
 176                         Type [] async_param_types = new Type [params_num + 2];\r
 177 \r
 178                         param_types.CopyTo (async_param_types, 0);\r
 179 \r
 180                         async_param_types [params_num] = TypeManager.asynccallback_type;\r
 181                         async_param_types [params_num + 1] = TypeManager.object_type;\r
 182 \r
 183                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual |\r
 184                                 MethodAttributes.NewSlot;\r
 185                         \r
 186                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",\r
 187                                                                        mattr,\r
 188                                                                        cc,\r
 189                                                                        TypeManager.iasyncresult_type,\r
 190                                                                        async_param_types);\r
 191 \r
 192                         for (i = 0 ; i < param_types.Length; i++) {\r
 193                                 Parameter p = Parameters.FixedParameters [i];\r
 194                                 string name = p.Name;\r
 195                                 BeginInvokeBuilder.DefineParameter (i + 1, p.Attributes, name); \r
 196                         }\r
 197                         \r
 198                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");\r
 199                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");\r
 200                         \r
 201                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);\r
 202 \r
 203                         Parameter [] async_params = new Parameter [params_num + 2];\r
 204                         if (params_num > 0)\r
 205                                 Parameters.FixedParameters.CopyTo (async_params, 0);\r
 206 \r
 207                         async_params [params_num] = new Parameter ("System.AsyncCallback", "callback",\r
 208                                                                    Parameter.Modifier.NONE, null);\r
 209                         async_params [params_num + 1] = new Parameter ("System.IAsyncResult", "object",\r
 210                                                                    Parameter.Modifier.NONE, null);\r
 211 \r
 212                         TypeManager.RegisterMethod (BeginInvokeBuilder,\r
 213                                                     new InternalParameters (\r
 214                                                             parent,\r
 215                                                             new Parameters (async_params, null, Location)),\r
 216                                                     async_param_types);\r
 217 \r
 218                         //\r
 219                         // EndInvoke\r
 220                         //\r
 221                         Type [] end_param_types = new Type [1];\r
 222                         end_param_types [0] = TypeManager.iasyncresult_type;\r
 223                         \r
 224                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke",\r
 225                                                                      mattr,\r
 226                                                                      cc,\r
 227                                                                      ret_type,\r
 228                                                                      end_param_types);\r
 229                         EndInvokeBuilder.DefineParameter (1, ParameterAttributes.None, "result");\r
 230                         \r
 231                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);\r
 232 \r
 233                         Parameter [] end_params = new Parameter [1];\r
 234                         end_params [0] = new Parameter ("System.IAsyncResult", "result",\r
 235                                                         Parameter.Modifier.NONE, null);\r
 236 \r
 237                         TypeManager.RegisterMethod (EndInvokeBuilder,\r
 238                                                     new InternalParameters (\r
 239                                                             parent,\r
 240                                                             new Parameters (end_params, null, Location)),\r
 241                                                     end_param_types);\r
 242 \r
 243                         return true;\r
 244                 }\r
 245 \r
 246                 /// <summary>\r
 247                 ///  Verifies whether the method in question is compatible with the delegate\r
 248                 ///  Returns the method itself if okay and null if not.\r
 249                 /// </summary>\r
 250                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,\r
 251                                                        Location loc)\r
 252                 {\r
 253                         ParameterData pd = Invocation.GetParameterData (mb);\r
 254 \r
 255                         Expression ml = Expression.MemberLookup (\r
 256                                 ec, delegate_type, "Invoke", loc);\r
 257 \r
 258                         if (!(ml is MethodGroupExpr)) {\r
 259                                 Report.Error (-100, loc, "Internal error : could not find Invoke method!");\r
 260                                 return null;\r
 261                         }\r
 262 \r
 263                         MethodBase invoke_mb = ((MethodGroupExpr) ml).Methods [0];\r
 264 \r
 265                         ParameterData invoke_pd = Invocation.GetParameterData (invoke_mb);\r
 266 \r
 267                         bool mismatch = false;\r
 268                         for (int i = pd.Count; i > 0; ) {\r
 269                                 i--;\r
 270 \r
 271                                 if (invoke_pd.ParameterType (i) == pd.ParameterType (i))\r
 272                                         continue;\r
 273                                 else {\r
 274                                         mismatch = true;\r
 275                                         break;\r
 276                                 }\r
 277                         }\r
 278 \r
 279                         if (mismatch) {\r
 280                                 Report.Error (\r
 281                                         123, loc, "Method '" + Invocation.FullMethodDesc (mb) +\r
 282                                         "' does not match delegate '" +\r
 283                                         FullDelegateDesc (delegate_type, invoke_mb, invoke_pd) + "'");\r
 284                                 return null;\r
 285                         }\r
 286 \r
 287                         if (((MethodInfo) invoke_mb).ReturnType == ((MethodInfo) mb).ReturnType)\r
 288                                 return mb;\r
 289                         else\r
 290                                 mismatch = true;\r
 291 \r
 292                         if (mismatch) {\r
 293                                 Report.Error (123, loc, "Method '" + Invocation.FullMethodDesc (mb) +\r
 294                                               "' does not match delegate '" +\r
 295                                               FullDelegateDesc (delegate_type, invoke_mb, invoke_pd) + "'");\r
 296                                 return null;\r
 297                         }\r
 298 \r
 299                         return null;\r
 300                 }\r
 301 \r
 302                 // <summary>\r
 303                 //  Verifies whether the invocation arguments are compatible with the\r
 304                 //  delegate's target method\r
 305                 // </summary>\r
 306                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type, ArrayList args,\r
 307                                                         Location loc)\r
 308                 {\r
 309                         int arg_count;\r
 310 \r
 311                         if (args == null)\r
 312                                 arg_count = 0;\r
 313                         else\r
 314                                 arg_count = args.Count;\r
 315 \r
 316                         Expression ml = Expression.MemberLookup (\r
 317                                 ec, delegate_type, "Invoke", loc);\r
 318                         \r
 319                         if (!(ml is MethodGroupExpr)) {\r
 320                                 Report.Error (-100, loc, "Internal error : could not find Invoke method!");\r
 321                                 return false;\r
 322                         }\r
 323                         \r
 324                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];\r
 325 \r
 326                         ParameterData pd = Invocation.GetParameterData (mb);\r
 327                         \r
 328                         if (pd.Count != arg_count) {\r
 329                                 Report.Error (1593, loc,\r
 330                                               "Delegate '" + delegate_type.ToString ()\r
 331                                               + "' does not take '" + arg_count + "' arguments");\r
 332                                 return false;\r
 333                         }\r
 334 \r
 335                         for (int i = arg_count; i > 0;) {\r
 336                                 i--;\r
 337                                 Expression conv;\r
 338                                 Argument a = (Argument) args [i];\r
 339                                 Expression a_expr = a.Expr;\r
 340                                 \r
 341                                 if (pd.ParameterType (i) != a_expr.Type) {\r
 342                                         \r
 343                                         conv = Expression.ConvertImplicitStandard (ec, a_expr, pd.ParameterType (i), loc);\r
 344 \r
 345                                         if (conv == null) {\r
 346                                                 Report.Error (1594, loc,\r
 347                                                               "Delegate '" + delegate_type.ToString () +\r
 348                                                               "' has some invalid arguments.");\r
 349 \r
 350                                                 Report.Error (1503, loc,\r
 351                                                        "Argument " + (i+1) +\r
 352                                                        ": Cannot convert from '" +\r
 353                                                        TypeManager.CSharpName (a_expr.Type)\r
 354                                                        + "' to '" + TypeManager.CSharpName (pd.ParameterType (i)) + "'");\r
 355                                                 return false;\r
 356                                         }\r
 357 \r
 358                                         if (a_expr != conv)\r
 359                                                 a.Expr = conv;\r
 360                                 }\r
 361                         }\r
 362 \r
 363                         return true;\r
 364                 }\r
 365 \r
 366                 /// <summary>\r
 367                 ///  Verifies whether the delegate in question is compatible with this one in\r
 368                 ///  order to determine if instantiation from the same is possible.\r
 369                 /// </summary>\r
 370                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)\r
 371                 {\r
 372                         Expression ml = Expression.MemberLookup (\r
 373                                 ec, delegate_type, "Invoke", loc);\r
 374                         \r
 375                         if (!(ml is MethodGroupExpr)) {\r
 376                                 Report.Error (-100, loc, "Internal error : could not find Invoke method!");\r
 377                                 return false;\r
 378                         }\r
 379                         \r
 380                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];\r
 381                         ParameterData pd = Invocation.GetParameterData (mb);\r
 382 \r
 383                         Expression probe_ml = Expression.MemberLookup (\r
 384                                 ec, delegate_type, "Invoke", loc);\r
 385                         \r
 386                         if (!(probe_ml is MethodGroupExpr)) {\r
 387                                 Report.Error (-100, loc, "Internal error : could not find Invoke method!");\r
 388                                 return false;\r
 389                         }\r
 390                         \r
 391                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];\r
 392                         ParameterData probe_pd = Invocation.GetParameterData (probe_mb);\r
 393                         \r
 394                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)\r
 395                                 return false;\r
 396 \r
 397                         if (pd.Count != probe_pd.Count)\r
 398                                 return false;\r
 399 \r
 400                         for (int i = pd.Count; i > 0; ) {\r
 401                                 i--;\r
 402 \r
 403                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||\r
 404                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))\r
 405                                         return false;\r
 406                         }\r
 407                         \r
 408                         return true;\r
 409                 }\r
 410                 \r
 411                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)\r
 412                 {\r
 413                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));\r
 414                         \r
 415                         sb.Append (" " + del_type.ToString ());\r
 416                         sb.Append (" (");\r
 417 \r
 418                         int length = pd.Count;\r
 419                         \r
 420                         for (int i = length; i > 0; ) {\r
 421                                 i--;\r
 422                                 \r
 423                                 sb.Append (TypeManager.CSharpName (pd.ParameterType (length - i - 1)));\r
 424                                 if (i != 0)\r
 425                                         sb.Append (", ");\r
 426                         }\r
 427                         \r
 428                         sb.Append (")");\r
 429                         return sb.ToString ();\r
 430                         \r
 431                 }\r
 432                 \r
 433                 // Hack around System.Reflection as found everywhere else\r
 434                 public MemberInfo [] FindMembers (MemberTypes mt, BindingFlags bf, MemberFilter filter, object criteria)\r
 435                 {\r
 436                         ArrayList members = new ArrayList ();\r
 437 \r
 438                         if ((mt & MemberTypes.Method) != 0) {\r
 439                                 if (filter (ConstructorBuilder, criteria))\r
 440                                         members.Add (ConstructorBuilder);\r
 441 \r
 442                                 if (filter (InvokeBuilder, criteria))\r
 443                                         members.Add (InvokeBuilder);\r
 444 \r
 445                                 if (filter (BeginInvokeBuilder, criteria))\r
 446                                         members.Add (BeginInvokeBuilder);\r
 447 \r
 448                                 if (filter (EndInvokeBuilder, criteria))\r
 449                                         members.Add (EndInvokeBuilder);\r
 450                         }\r
 451 \r
 452                         int count = members.Count;\r
 453 \r
 454                         if (count > 0) {\r
 455                                 MemberInfo [] mi = new MemberInfo [count];\r
 456                                 members.CopyTo (mi, 0);\r
 457                                 return mi;\r
 458                         }\r
 459 \r
 460                         return null;\r
 461                 }\r
 462                 \r
 463                 public void CloseDelegate ()\r
 464                 {\r
 465                         TypeBuilder.CreateType ();\r
 466                 }\r
 467                 \r
 468                 public Expression InstanceExpression {\r
 469                         get {\r
 470                                 return instance_expr;\r
 471                         }\r
 472                         set {\r
 473                                 instance_expr = value;\r
 474                         }\r
 475                 }\r
 476 \r
 477                 public MethodBase TargetMethod {\r
 478                         get {\r
 479                                 return delegate_method;\r
 480                         }\r
 481                         set {\r
 482                                 delegate_method = value;\r
 483                         }\r
 484                 }\r
 485 \r
 486                 public Type TargetReturnType {\r
 487                         get {\r
 488                                 return ret_type;\r
 489                         }\r
 490                 }\r
 491 \r
 492                 public Type [] ParameterTypes {\r
 493                         get {\r
 494                                 return param_types;\r
 495                         }\r
 496                 }\r
 497                 \r
 498         }\r
 499 \r
 500         public class NewDelegate : Expression {\r
 501 \r
 502                 public ArrayList Arguments;\r
 503 \r
 504                 MethodBase constructor_method;\r
 505                 MethodBase delegate_method;\r
 506                 Expression delegate_instance_expr;\r
 507 \r
 508                 Location Location;\r
 509                 \r
 510                 public NewDelegate (Type type, ArrayList Arguments, Location loc)\r
 511                 {\r
 512                         this.type = type;\r
 513                         this.Arguments = Arguments;\r
 514                         this.Location  = loc; \r
 515                 }\r
 516 \r
 517                 public override Expression DoResolve (EmitContext ec)\r
 518                 {\r
 519                         if (Arguments == null) {\r
 520                                 Report.Error (-11, Location,\r
 521                                               "Delegate creation expression takes only one argument");\r
 522                                 return null;\r
 523                         }\r
 524                         \r
 525                         if (Arguments.Count != 1) {\r
 526                                 Report.Error (-11, Location,\r
 527                                               "Delegate creation expression takes only one argument");\r
 528                                 return null;\r
 529                         }\r
 530 \r
 531                         Expression ml = Expression.MemberLookup (\r
 532                                 ec, type, ".ctor", Location);\r
 533 \r
 534                         if (!(ml is MethodGroupExpr)) {\r
 535                                 Report.Error (-100, Location, "Internal error : Could not find delegate constructor!");\r
 536                                 return null;\r
 537                         }\r
 538 \r
 539                         constructor_method = ((MethodGroupExpr) ml).Methods [0];\r
 540                         \r
 541                         Argument a = (Argument) Arguments [0];\r
 542                         \r
 543                         if (!a.Resolve (ec, Location))\r
 544                                 return null;\r
 545                         \r
 546                         Expression e = a.Expr;\r
 547 \r
 548                         if (e is MethodGroupExpr) {\r
 549                                 MethodGroupExpr mg = (MethodGroupExpr) e;\r
 550 \r
 551                                 if (mg.Methods.Length > 1) {\r
 552                                         Report.Error (-14, Location, "Ambiguous method reference in delegate creation");\r
 553                                         return null;\r
 554                                 }\r
 555                                 \r
 556                                 delegate_method  = Delegate.VerifyMethod (ec, type, mg.Methods [0], Location);\r
 557                                 \r
 558                                 if (delegate_method == null)\r
 559                                         return null;\r
 560 \r
 561                                 if (mg.InstanceExpression != null)\r
 562                                         delegate_instance_expr = mg.InstanceExpression.Resolve (ec);\r
 563                                 else {\r
 564                                         if (!ec.IsStatic)\r
 565                                                 delegate_instance_expr = ec.This;\r
 566                                         else\r
 567                                                 delegate_instance_expr = null;\r
 568                                 }\r
 569 \r
 570                                 if (delegate_instance_expr != null)\r
 571                                         if (delegate_instance_expr.Type.IsValueType)\r
 572                                                 delegate_instance_expr = new BoxedCast (delegate_instance_expr);\r
 573                                 \r
 574                                 eclass = ExprClass.Value;\r
 575                                 return this;\r
 576                         }\r
 577 \r
 578                         Type e_type = e.Type;\r
 579 \r
 580                         if (!TypeManager.IsDelegateType (e_type)) {\r
 581                                 Report.Error (-12, Location, "Cannot create a delegate from something " +\r
 582                                               "not a delegate or a method.");\r
 583                                 return null;\r
 584                         }\r
 585 \r
 586                         // This is what MS' compiler reports. We could always choose\r
 587                         // to be more verbose and actually give delegate-level specifics\r
 588                         \r
 589                         if (!Delegate.VerifyDelegate (ec, type, e_type, Location)) {\r
 590                                 Report.Error (29, Location, "Cannot implicitly convert type '" + e_type + "' " +\r
 591                                               "to type '" + type + "'");\r
 592                                 return null;\r
 593                         }\r
 594 \r
 595                         Expression invoke_method = Expression.MemberLookup (\r
 596                                 ec, e_type, "Invoke", MemberTypes.Method,\r
 597                                 Expression.AllBindingFlags, Location);\r
 598 \r
 599                         if (invoke_method == null) {\r
 600                                 Report.Error (-200, Location, "Internal error ! COuld not find Invoke method!");\r
 601                                 return null;\r
 602                         }\r
 603                                 \r
 604                         delegate_instance_expr = e;\r
 605                         delegate_method        = ((MethodGroupExpr) invoke_method).Methods [0];\r
 606                         \r
 607                         eclass = ExprClass.Value;\r
 608                         return this;\r
 609                 }\r
 610                 \r
 611                 public override void Emit (EmitContext ec)\r
 612                 {\r
 613                         if (delegate_instance_expr == null)\r
 614                                 ec.ig.Emit (OpCodes.Ldnull);\r
 615                         else\r
 616                                 delegate_instance_expr.Emit (ec);\r
 617                         \r
 618                         ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);\r
 619                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);\r
 620                 }\r
 621         }\r
 622 \r
 623         public class DelegateInvocation : ExpressionStatement {\r
 624 \r
 625                 public Expression InstanceExpr;\r
 626                 public ArrayList  Arguments;\r
 627                 public Location   Location;\r
 628 \r
 629                 MethodBase method;\r
 630                 \r
 631                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)\r
 632                 {\r
 633                         this.InstanceExpr = instance_expr;\r
 634                         this.Arguments = args;\r
 635                         this.Location = loc;\r
 636                 }\r
 637 \r
 638                 public override Expression DoResolve (EmitContext ec)\r
 639                 {\r
 640                         Type del_type = InstanceExpr.Type;\r
 641 \r
 642                         if (del_type == null)\r
 643                                 return null;\r
 644                         \r
 645                         if (Arguments != null){\r
 646                                 for (int i = Arguments.Count; i > 0;){\r
 647                                         --i;\r
 648                                         Argument a = (Argument) Arguments [i];\r
 649                                         \r
 650                                         if (!a.Resolve (ec, Location))\r
 651                                                 return null;\r
 652                                 }\r
 653                         }\r
 654                         \r
 655                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, Location))\r
 656                                 return null;\r
 657 \r
 658                         Expression ml = Expression.MemberLookup (ec, del_type, "Invoke", Location);\r
 659                         \r
 660                         if (!(ml is MethodGroupExpr)) {\r
 661                                 Report.Error (-100, Location, "Internal error : could not find Invoke method!");\r
 662                                 return null;\r
 663                         }\r
 664                         \r
 665                         method = ((MethodGroupExpr) ml).Methods [0];\r
 666                         \r
 667                         type = ((MethodInfo) method).ReturnType;\r
 668                         \r
 669                         eclass = ExprClass.Value;\r
 670                         \r
 671                         return this;\r
 672                 }\r
 673 \r
 674                 public override void Emit (EmitContext ec)\r
 675                 {\r
 676                         Delegate del = TypeManager.LookupDelegate (InstanceExpr.Type);\r
 677 \r
 678                         //\r
 679                         // Invocation on delegates call the virtual Invoke member\r
 680                         // so we are always `instance' calls\r
 681                         //\r
 682                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments);\r
 683                 }\r
 684 \r
 685                 public override void EmitStatement (EmitContext ec)\r
 686                 {\r
 687                         Emit (ec);\r
 688                         // \r
 689                         // Pop the return value if there is one\r
 690                         //\r
 691                         if (method is MethodInfo){\r
 692                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)\r
 693                                         ec.ig.Emit (OpCodes.Pop);\r
 694                         }\r
 695                 }\r
 696 \r
 697         }\r
 698 }\r