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