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