mcs/gmcs/delegate.cs

   1 //
   2 // delegate.cs: Delegate Handler
   3 //
   4 // Authors:
   5 //     Ravi Pratap (ravi@ximian.com)
   6 //     Miguel de Icaza (miguel@ximian.com)
   7 //
   8 // Licensed under the terms of the GNU GPL
   9 //
  10 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  11 //
  12 //
  13
  14 using System;
  15 using System.Collections;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.Text;
  19
  20 namespace Mono.CSharp {
  21
  22         /// <summary>
  23         ///   Holds Delegates
  24         /// </summary>
  25         public class Delegate : DeclSpace {
  26                 public Expression ReturnType;
  27                 public Parameters      Parameters;
  28
  29                 public ConstructorBuilder ConstructorBuilder;
  30                 public MethodBuilder      InvokeBuilder;
  31                 public MethodBuilder      BeginInvokeBuilder;
  32                 public MethodBuilder      EndInvokeBuilder;
  33
  34                 Type [] param_types;
  35                 Type ret_type;
  36
  37                 static string[] attribute_targets = new string [] { "type", "return" };
  38
  39                 Expression instance_expr;
  40                 MethodBase delegate_method;
  41                 ReturnParameter return_attributes;
  42
  43                 const int AllowedModifiers =
  44                         Modifiers.NEW |
  45                         Modifiers.PUBLIC |
  46                         Modifiers.PROTECTED |
  47                         Modifiers.INTERNAL |
  48                         Modifiers.UNSAFE |
  49                         Modifiers.PRIVATE;
  50
  51                 public Delegate (NamespaceEntry ns, TypeContainer parent, Expression type,
  52                                  int mod_flags, MemberName name, Parameters param_list,
  53                                  Attributes attrs)
  54                         : base (ns, parent, name, attrs)
  55
  56                 {
  57                         this.ReturnType = type;
  58                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  59                                                            IsTopLevel ? Modifiers.INTERNAL :
  60                                                            Modifiers.PRIVATE, name.Location);
  61                         Parameters      = param_list;
  62                 }
  63
  64                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  65                 {
  66                         if (a.Target == AttributeTargets.ReturnValue) {
  67                                 if (return_attributes == null)
  68                                         return_attributes = new ReturnParameter (InvokeBuilder, Location);
  69
  70                                 return_attributes.ApplyAttributeBuilder (a, cb);
  71                                 return;
  72                         }
  73
  74                         base.ApplyAttributeBuilder (a, cb);
  75                 }
  76
  77                 public override TypeBuilder DefineType ()
  78                 {
  79                         if (TypeBuilder != null)
  80                                 return TypeBuilder;
  81
  82                         ec = new EmitContext (this, this, Location, null, null, ModFlags, false);
  83
  84                         if (IsGeneric) {
  85                                 foreach (TypeParameter type_param in TypeParameters)
  86                                         if (!type_param.Resolve (this))
  87                                                 return null;
  88                         }
  89
  90                         if (TypeManager.multicast_delegate_type == null && !RootContext.StdLib) {
  91                                 Namespace system = Namespace.LookupNamespace ("System", true);
  92                                 TypeExpr expr = system.Lookup (this, "MulticastDelegate", Location) as TypeExpr;
  93                                 TypeManager.multicast_delegate_type = expr.ResolveType (ec);
  94                         }
  95
  96                         if (TypeManager.multicast_delegate_type == null)
  97                                 Report.Error (-100, Location, "Internal error: delegate used before " +
  98                                               "System.MulticastDelegate is resolved.  This can only " +
  99                                               "happen during corlib compilation, when using a delegate " +
 100                                               "in any of the `core' classes.  See bug #72015 for details.");
 101
 102                         if (IsTopLevel) {
 103                                 if (TypeManager.NamespaceClash (Name, Location))
 104                                         return null;
 105
 106                                 ModuleBuilder builder = CodeGen.Module.Builder;
 107
 108                                 TypeBuilder = builder.DefineType (
 109                                         Name, TypeAttr, TypeManager.multicast_delegate_type);
 110                         } else {
 111                                 TypeBuilder builder = Parent.TypeBuilder;
 112
 113                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
 114                                 TypeBuilder = builder.DefineNestedType (
 115                                         name, TypeAttr, TypeManager.multicast_delegate_type);
 116                         }
 117
 118                         TypeManager.AddUserType (Name, this);
 119
 120                         if (IsGeneric) {
 121                                 string[] param_names = new string [TypeParameters.Length];
 122                                 for (int i = 0; i < TypeParameters.Length; i++)
 123                                         param_names [i] = TypeParameters [i].Name;
 124
 125                                 GenericTypeParameterBuilder[] gen_params;
 126                                 gen_params = TypeBuilder.DefineGenericParameters (param_names);
 127
 128                                 int offset = CountTypeParameters - CurrentTypeParameters.Length;
 129                                 for (int i = offset; i < gen_params.Length; i++)
 130                                         CurrentTypeParameters [i - offset].Define (gen_params [i]);
 131
 132                                 foreach (TypeParameter type_param in CurrentTypeParameters) {
 133                                         if (!type_param.Resolve (this))
 134                                                 return null;
 135                                 }
 136
 137                                 for (int i = offset; i < gen_params.Length; i++)
 138                                         CurrentTypeParameters [i - offset].DefineConstraints ();
 139
 140                                 Expression current = new SimpleName (
 141                                         MemberName.Basename, TypeParameters, Location);
 142                                 current = current.ResolveAsTypeTerminal (ec);
 143                                 if (current == null)
 144                                         return null;
 145
 146                                 CurrentType = current.Type;
 147                         }
 148
 149                         return TypeBuilder;
 150                 }
 151
 152                 public override bool Define ()
 153                 {
 154                         MethodAttributes mattr;
 155                         int i;
 156
 157                         if (IsGeneric) {
 158                                 foreach (TypeParameter type_param in TypeParameters)
 159                                         type_param.DefineType (ec);
 160                         }
 161
 162                         if (ec == null)
 163                                 throw new InternalErrorException ("Define called before DefineType?");
 164
 165                         // FIXME: POSSIBLY make this static, as it is always constant
 166                         //
 167                         Type [] const_arg_types = new Type [2];
 168                         const_arg_types [0] = TypeManager.object_type;
 169                         const_arg_types [1] = TypeManager.intptr_type;
 170
 171                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 172                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 173
 174                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 175                                                                             CallingConventions.Standard,
 176                                                                             const_arg_types);
 177
 178                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 179                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 180                         //
 181                         // HACK because System.Reflection.Emit is lame
 182                         //
 183                         Parameter [] fixed_pars = new Parameter [2];
 184                         fixed_pars [0] = new Parameter (TypeManager.system_object_expr, "object",
 185                                                         Parameter.Modifier.NONE, null, Location);
 186                         fixed_pars [1] = new Parameter (TypeManager.system_intptr_expr, "method",
 187                                                         Parameter.Modifier.NONE, null, Location);
 188                         Parameters const_parameters = new Parameters (fixed_pars, null);
 189
 190                         TypeManager.RegisterMethod (
 191                                 ConstructorBuilder,
 192                                 new InternalParameters (const_arg_types, const_parameters),
 193                                 const_arg_types);
 194
 195
 196                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 197
 198                         //
 199                         // Here the various methods like Invoke, BeginInvoke etc are defined
 200                         //
 201                         // First, call the `out of band' special method for
 202                         // defining recursively any types we need:
 203
 204                         param_types = Parameters.GetParameterInfo (ec);
 205                         if (param_types == null)
 206                                 return false;
 207
 208                         //
 209                         // Invoke method
 210                         //
 211
 212                         // Check accessibility
 213                         foreach (Type partype in param_types){
 214                                 if (!Parent.AsAccessible (partype, ModFlags)) {
 215                                         Report.Error (59, Location,
 216                                                       "Inconsistent accessibility: parameter type `" +
 217                                                       TypeManager.CSharpName (partype) + "' is less " +
 218                                                       "accessible than delegate `" + Name + "'");
 219                                         return false;
 220                                 }
 221                                 if (partype.IsPointer && !UnsafeOK (Parent))
 222                                         return false;
 223                         }
 224
 225                         ReturnType = ReturnType.ResolveAsTypeTerminal (ec);
 226                         if (ReturnType == null)
 227                             return false;
 228
 229                         ret_type = ReturnType.Type;
 230                         if (ret_type == null)
 231                                 return false;
 232
 233                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 234                                 Report.Error (58, Location,
 235                                               "Inconsistent accessibility: return type `" +
 236                                               TypeManager.CSharpName (ret_type) + "' is less " +
 237                                               "accessible than delegate `" + Name + "'");
 238                                 return false;
 239                         }
 240
 241                         if (ret_type.IsPointer && !UnsafeOK (Parent))
 242                                 return false;
 243
 244                         if (RootContext.StdLib && (ret_type == TypeManager.arg_iterator_type || ret_type == TypeManager.typed_reference_type)) {
 245                                 Method.Error1599 (Location, ret_type);
 246                                 return false;
 247                         }
 248
 249                         //
 250                         // We don't have to check any others because they are all
 251                         // guaranteed to be accessible - they are standard types.
 252                         //
 253
 254                         CallingConventions cc = Parameters.GetCallingConvention ();
 255
 256                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 257
 258                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 259                                                                   mattr,
 260                                                                   cc,
 261                                                                   ret_type,
 262                                                                   param_types);
 263
 264                         //
 265                         // Define parameters, and count out/ref parameters
 266                         //
 267                         int out_params = 0;
 268                         i = 0;
 269                         if (Parameters.FixedParameters != null){
 270                                 int top = Parameters.FixedParameters.Length;
 271                                 Parameter p;
 272
 273                                 for (; i < top; i++) {
 274                                         p = Parameters.FixedParameters [i];
 275                                         p.DefineParameter (ec, InvokeBuilder, null, i + 1);
 276
 277                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 278                                                 out_params++;
 279                                 }
 280                         }
 281                         if (Parameters.ArrayParameter != null){
 282                                 if (TypeManager.param_array_type == null && !RootContext.StdLib) {
 283                                         Namespace system = Namespace.LookupNamespace ("System", true);
 284                                         TypeExpr expr = system.Lookup (this, "ParamArrayAttribute", Location) as TypeExpr;
 285                                         TypeManager.param_array_type = expr.ResolveType (ec);
 286                                 }
 287
 288                                 if (TypeManager.cons_param_array_attribute == null) {
 289                                         Type [] void_arg = { };
 290                                         TypeManager.cons_param_array_attribute = TypeManager.GetConstructor (
 291                                                 TypeManager.param_array_type, void_arg);
 292                                 }
 293
 294                                 ParameterBuilder pb = InvokeBuilder.DefineParameter (
 295                                         i + 1, Parameters.ArrayParameter.Attributes,Parameters.ArrayParameter.Name);
 296
 297                                 pb.SetCustomAttribute (
 298                                         new CustomAttributeBuilder (TypeManager.cons_param_array_attribute, new object [0]));
 299                         }
 300
 301                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 302
 303                         TypeManager.RegisterMethod (InvokeBuilder,
 304                                                     new InternalParameters (param_types, Parameters),
 305                                                     param_types);
 306
 307                         //
 308                         // BeginInvoke
 309                         //
 310                         int params_num = param_types.Length;
 311                         Type [] async_param_types = new Type [params_num + 2];
 312
 313                         param_types.CopyTo (async_param_types, 0);
 314
 315                         async_param_types [params_num] = TypeManager.asynccallback_type;
 316                         async_param_types [params_num + 1] = TypeManager.object_type;
 317
 318                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 319                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 320
 321                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 322                                                                        mattr,
 323                                                                        cc,
 324                                                                        TypeManager.iasyncresult_type,
 325                                                                        async_param_types);
 326
 327                         i = 0;
 328                         if (Parameters.FixedParameters != null){
 329                                 int top = Parameters.FixedParameters.Length;
 330                                 Parameter p;
 331
 332                                 for (i = 0 ; i < top; i++) {
 333                                         p = Parameters.FixedParameters [i];
 334
 335                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1);
 336                                 }
 337                         }
 338                         if (Parameters.ArrayParameter != null){
 339                                 Parameter p = Parameters.ArrayParameter;
 340                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1);
 341
 342                                 i++;
 343                         }
 344
 345                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 346                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 347
 348                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 349
 350                         Parameter [] async_params = new Parameter [params_num + 2];
 351                         int n = 0;
 352                         if (Parameters.FixedParameters != null){
 353                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 354                                 n = Parameters.FixedParameters.Length;
 355                         }
 356                         if (Parameters.ArrayParameter != null)
 357                                 async_params [n] = Parameters.ArrayParameter;
 358
 359                         async_params [params_num] = new Parameter (
 360                                 TypeManager.system_asynccallback_expr, "callback",
 361                                                                    Parameter.Modifier.NONE, null, Location);
 362                         async_params [params_num + 1] = new Parameter (
 363                                 TypeManager.system_object_expr, "object",
 364                                                                    Parameter.Modifier.NONE, null, Location);
 365
 366                         Parameters async_parameters = new Parameters (async_params, null);
 367
 368                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 369                                                     new InternalParameters (async_parameters.GetParameterInfo (ec), async_parameters),
 370                                                     async_param_types);
 371
 372                         //
 373                         // EndInvoke is a bit more interesting, all the parameters labeled as
 374                         // out or ref have to be duplicated here.
 375                         //
 376
 377                         Type [] end_param_types = new Type [out_params + 1];
 378                         Parameter [] end_params = new Parameter [out_params + 1];
 379                         int param = 0;
 380                         if (out_params > 0){
 381                                 int top = Parameters.FixedParameters.Length;
 382                                 for (i = 0; i < top; i++){
 383                                         Parameter p = Parameters.FixedParameters [i];
 384                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 385                                                 continue;
 386
 387                                         end_param_types [param] = param_types [i];
 388                                         end_params [param] = p;
 389                                         param++;
 390                                 }
 391                         }
 392                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 393                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null, Location);
 394
 395                         //
 396                         // Create method, define parameters, register parameters with type system
 397                         //
 398                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 399                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 400
 401                         //
 402                         // EndInvoke: Label the parameters
 403                         //
 404                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 405                         for (i = 0; i < end_params.Length-1; i++){
 406                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 407                         }
 408
 409                         Parameters end_parameters = new Parameters (end_params, null);
 410
 411                         TypeManager.RegisterMethod (
 412                                 EndInvokeBuilder,
 413                                 new InternalParameters (end_parameters.GetParameterInfo (ec), end_parameters),
 414                                 end_param_types);
 415
 416                         return true;
 417                 }
 418
 419                 public override void Emit ()
 420                 {
 421                         if (OptAttributes != null) {
 422                                 Parameters.LabelParameters (ec, InvokeBuilder);
 423                                 OptAttributes.Emit (ec, this);
 424                         }
 425
 426                         base.Emit ();
 427                 }
 428
 429                 protected override TypeAttributes TypeAttr {
 430                         get {
 431                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 432                                         TypeAttributes.Class | TypeAttributes.Sealed |
 433                                         base.TypeAttr;
 434                         }
 435                 }
 436
 437                 public override string[] ValidAttributeTargets {
 438                         get {
 439                                 return attribute_targets;
 440                         }
 441                 }
 442
 443                 //TODO: duplicate
 444                 protected override bool VerifyClsCompliance (DeclSpace ds)
 445                 {
 446                         if (!base.VerifyClsCompliance (ds)) {
 447                                 return false;
 448                         }
 449
 450                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 451
 452                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 453                                 Report.Error (3002, Location, "Return type of `{0}' is not CLS-compliant", GetSignatureForError ());
 454                         }
 455                         return true;
 456                 }
 457
 458                 //
 459                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 460                 // to extract the signature of a delegate.
 461                 //
 462                 public static MethodGroupExpr GetInvokeMethod (EmitContext ec, Type delegate_type,
 463                                                                Location loc)
 464                 {
 465                         Expression ml = Expression.MemberLookup (
 466                                 ec, delegate_type, "Invoke", loc);
 467
 468                         MethodGroupExpr mg = ml as MethodGroupExpr;
 469                         if (mg == null) {
 470                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 471                                 return null;
 472                         }
 473
 474                         return mg;
 475                 }
 476
 477                 /// <summary>
 478                 ///  Verifies whether the method in question is compatible with the delegate
 479                 ///  Returns the method itself if okay and null if not.
 480                 /// </summary>
 481                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type,
 482                                                        MethodGroupExpr old_mg, MethodBase mb,
 483                                                        Location loc)
 484                 {
 485                         MethodGroupExpr mg = GetInvokeMethod (ec, delegate_type, loc);
 486                         if (mg == null)
 487                                 return null;
 488
 489                         if (old_mg.HasTypeArguments)
 490                                 mg.HasTypeArguments = true;
 491
 492                         MethodBase invoke_mb = mg.Methods [0];
 493                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 494
 495                         if (!mg.HasTypeArguments &&
 496                             !TypeManager.InferTypeArguments (ec, invoke_pd, ref mb))
 497                                 return null;
 498
 499                         ParameterData pd = TypeManager.GetParameterData (mb);
 500
 501                         if (invoke_pd.Count != pd.Count)
 502                                 return null;
 503
 504                         for (int i = pd.Count; i > 0; ) {
 505                                 i--;
 506
 507                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 508                                 Type pd_type = pd.ParameterType (i);
 509                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 510                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 511
 512                                 if (invoke_pd_type == pd_type &&
 513                                     invoke_pd_type_mod == pd_type_mod)
 514                                         continue;
 515
 516                                 if (invoke_pd_type.IsSubclassOf (pd_type) &&
 517                                     invoke_pd_type_mod == pd_type_mod)
 518                                         if (RootContext.Version == LanguageVersion.ISO_1) {
 519                                                 Report.FeatureIsNotStandardized (loc, "contravariance");
 520                                                 return null;
 521                                         } else
 522                                                 continue;
 523
 524                                 return null;
 525                         }
 526
 527                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 528                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 529                         if (invoke_mb_retval == mb_retval)
 530                                 return mb;
 531
 532                         if (mb_retval.IsSubclassOf (invoke_mb_retval))
 533                                 if (RootContext.Version == LanguageVersion.ISO_1) {
 534                                         Report.FeatureIsNotStandardized (loc, "covariance");
 535                                         return null;
 536                                 }
 537                                 else
 538                                         return mb;
 539
 540                         return null;
 541                 }
 542
 543                 // <summary>
 544                 //  Verifies whether the invocation arguments are compatible with the
 545                 //  delegate's target method
 546                 // </summary>
 547                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 548                                                         ArrayList args, Location loc)
 549                 {
 550                         int arg_count;
 551
 552                         if (args == null)
 553                                 arg_count = 0;
 554                         else
 555                                 arg_count = args.Count;
 556
 557                         Expression ml = Expression.MemberLookup (
 558                                 ec, delegate_type, "Invoke", loc);
 559
 560                         MethodGroupExpr me = ml as MethodGroupExpr;
 561                         if (me == null) {
 562                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 563                                 return false;
 564                         }
 565
 566                         MethodBase mb = me.Methods [0];
 567                         ParameterData pd = TypeManager.GetParameterData (mb);
 568
 569                         int pd_count = pd.Count;
 570
 571                         bool params_method = (pd_count != 0) &&
 572                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 573
 574                         bool is_params_applicable = false;
 575                         bool is_applicable = Invocation.IsApplicable (ec, me, args, arg_count, ref mb);
 576
 577                         if (!is_applicable && params_method &&
 578                             Invocation.IsParamsMethodApplicable (ec, me, args, arg_count, ref mb))
 579                                 is_applicable = is_params_applicable = true;
 580
 581                         if (!is_applicable && !params_method && arg_count != pd_count) {
 582                                 Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 583                                         TypeManager.CSharpName (delegate_type), arg_count);
 584                                 return false;
 585                         }
 586
 587                         return Invocation.VerifyArgumentsCompat (
 588                                         ec, args, arg_count, mb,
 589                                         is_params_applicable || (!is_applicable && params_method),
 590                                         delegate_type, false, loc);
 591                 }
 592
 593                 /// <summary>
 594                 ///  Verifies whether the delegate in question is compatible with this one in
 595                 ///  order to determine if instantiation from the same is possible.
 596                 /// </summary>
 597                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 598                 {
 599                         Expression ml = Expression.MemberLookup (
 600                                 ec, delegate_type, "Invoke", loc);
 601
 602                         if (!(ml is MethodGroupExpr)) {
 603                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 604                                 return false;
 605                         }
 606
 607                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 608                         ParameterData pd = TypeManager.GetParameterData (mb);
 609
 610                         Expression probe_ml = Expression.MemberLookup (
 611                                 ec, delegate_type, "Invoke", loc);
 612
 613                         if (!(probe_ml is MethodGroupExpr)) {
 614                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 615                                 return false;
 616                         }
 617
 618                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 619                         ParameterData probe_pd = TypeManager.GetParameterData (probe_mb);
 620
 621                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 622                                 return false;
 623
 624                         if (pd.Count != probe_pd.Count)
 625                                 return false;
 626
 627                         for (int i = pd.Count; i > 0; ) {
 628                                 i--;
 629
 630                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 631                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 632                                         return false;
 633                         }
 634
 635                         return true;
 636                 }
 637
 638                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 639                 {
 640                         StringBuilder sb = new StringBuilder ();
 641                         sb.Append (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 642                         sb.Append (" ");
 643                         sb.Append (TypeManager.CSharpName (del_type));
 644                         sb.Append (pd.GetSignatureForError ());
 645                         return sb.ToString ();
 646                 }
 647
 648                 // Hack around System.Reflection as found everywhere else
 649                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 650                                                         MemberFilter filter, object criteria)
 651                 {
 652                         ArrayList members = new ArrayList ();
 653
 654                         if ((mt & MemberTypes.Method) != 0) {
 655                                 if (ConstructorBuilder != null)
 656                                 if (filter (ConstructorBuilder, criteria))
 657                                         members.Add (ConstructorBuilder);
 658
 659                                 if (InvokeBuilder != null)
 660                                 if (filter (InvokeBuilder, criteria))
 661                                         members.Add (InvokeBuilder);
 662
 663                                 if (BeginInvokeBuilder != null)
 664                                 if (filter (BeginInvokeBuilder, criteria))
 665                                         members.Add (BeginInvokeBuilder);
 666
 667                                 if (EndInvokeBuilder != null)
 668                                 if (filter (EndInvokeBuilder, criteria))
 669                                         members.Add (EndInvokeBuilder);
 670                         }
 671
 672                         return new MemberList (members);
 673                 }
 674
 675                 public override MemberCache MemberCache {
 676                         get {
 677                                 return null;
 678                         }
 679                 }
 680
 681                 public Expression InstanceExpression {
 682                         get {
 683                                 return instance_expr;
 684                         }
 685                         set {
 686                                 instance_expr = value;
 687                         }
 688                 }
 689
 690                 public MethodBase TargetMethod {
 691                         get {
 692                                 return delegate_method;
 693                         }
 694                         set {
 695                                 delegate_method = value;
 696                         }
 697                 }
 698
 699                 public Type TargetReturnType {
 700                         get {
 701                                 return ret_type;
 702                         }
 703                 }
 704
 705                 public Type [] ParameterTypes {
 706                         get {
 707                                 return param_types;
 708                         }
 709                 }
 710
 711                 public override AttributeTargets AttributeTargets {
 712                         get {
 713                                 return AttributeTargets.Delegate;
 714                         }
 715                 }
 716
 717                 //
 718                 //   Represents header string for documentation comment.
 719                 //
 720                 public override string DocCommentHeader {
 721                         get { return "T:"; }
 722                 }
 723
 724                 protected override void VerifyObsoleteAttribute()
 725                 {
 726                         CheckUsageOfObsoleteAttribute (ret_type);
 727
 728                         foreach (Type type in param_types) {
 729                                 CheckUsageOfObsoleteAttribute (type);
 730                         }
 731                 }
 732         }
 733
 734         //
 735         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 736         //
 737         public abstract class DelegateCreation : Expression {
 738                 protected MethodBase constructor_method;
 739                 protected MethodBase delegate_method;
 740                 protected MethodGroupExpr method_group;
 741                 protected Expression delegate_instance_expression;
 742
 743                 public DelegateCreation () {}
 744
 745                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 746                 {
 747                         string method_desc;
 748                         MethodBase found_method = mg.Methods [0];
 749
 750                         if (mg.Methods.Length > 1)
 751                                 method_desc = found_method.Name;
 752                         else
 753                                 method_desc = Invocation.FullMethodDesc (found_method);
 754
 755                         Expression invoke_method = Expression.MemberLookup (
 756                                 ec, type, "Invoke", MemberTypes.Method,
 757                                 Expression.AllBindingFlags, loc);
 758                         MethodInfo method = ((MethodGroupExpr) invoke_method).Methods [0] as MethodInfo;
 759
 760                         ParameterData param = TypeManager.GetParameterData (method);
 761                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 762
 763                         if (!mg.HasTypeArguments &&
 764                             !TypeManager.InferTypeArguments (ec, param, ref found_method))
 765                                 Report.Error (411, loc, "The type arguments for " +
 766                                               "method `{0}' cannot be infered from " +
 767                                               "the usage. Try specifying the type " +
 768                                               "arguments explicitly.", method_desc);
 769                         else if (method.ReturnType != ((MethodInfo) found_method).ReturnType) {
 770                                 Report.Error (407, loc, "`{0}' has the wrong return type to match the delegate `{1}'", method_desc, delegate_desc);
 771                         } else {
 772                                 Report.Error (123, loc, "Method `{0}' does not match delegate `{1}'", method_desc, delegate_desc);
 773                         }
 774                 }
 775
 776                 public override void Emit (EmitContext ec)
 777                 {
 778                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 779                                 ec.ig.Emit (OpCodes.Ldnull);
 780                         else
 781                                 delegate_instance_expression.Emit (ec);
 782
 783                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 784                                 ec.ig.Emit (OpCodes.Dup);
 785                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 786                         } else
 787                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 788                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 789                 }
 790
 791                 protected bool ResolveConstructorMethod (EmitContext ec)
 792                 {
 793                         Expression ml = Expression.MemberLookup (
 794                                 ec, type, ".ctor", loc);
 795
 796                         if (!(ml is MethodGroupExpr)) {
 797                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 798                                 return false;
 799                         }
 800
 801                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 802                         return true;
 803                 }
 804
 805                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg,
 806                                                              bool check_only)
 807                 {
 808                         foreach (MethodInfo mi in mg.Methods){
 809                                 delegate_method  = Delegate.VerifyMethod (ec, type, mg, mi, loc);
 810
 811                                 if (delegate_method != null)
 812                                         break;
 813                         }
 814
 815                         if (delegate_method == null) {
 816                                 if (!check_only)
 817                                         Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 818                                 return null;
 819                         }
 820
 821                         //
 822                         // Check safe/unsafe of the delegate
 823                         //
 824                         if (!ec.InUnsafe){
 825                                 ParameterData param = TypeManager.GetParameterData (delegate_method);
 826                                 int count = param.Count;
 827
 828                                 for (int i = 0; i < count; i++){
 829                                         if (param.ParameterType (i).IsPointer){
 830                                                 Expression.UnsafeError (loc);
 831                                                 return null;
 832                                         }
 833                                 }
 834                         }
 835
 836                         //TODO: implement caching when performance will be low
 837                         IMethodData md = TypeManager.GetMethod (delegate_method);
 838                         if (md == null) {
 839                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 840                                         Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 841                                 }
 842                         } else {
 843                                 md.SetMemberIsUsed ();
 844                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 845                                         Report.Error (1618, loc, "Cannot create delegate with `{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 846                                 }
 847                         }
 848
 849                         if (mg.InstanceExpression != null)
 850                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 851                         else if (ec.IsStatic) {
 852                                 if (!delegate_method.IsStatic) {
 853                                         Report.Error (120, loc, "`{0}': An object reference is required for the nonstatic field, method or property",
 854                                                       TypeManager.CSharpSignature (delegate_method));
 855                                         return null;
 856                                 }
 857                                 delegate_instance_expression = null;
 858                         } else
 859                                 delegate_instance_expression = ec.GetThis (loc);
 860
 861                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 862                                 delegate_instance_expression = new BoxedCast (delegate_instance_expression);
 863
 864                         method_group = mg;
 865                         eclass = ExprClass.Value;
 866                         return this;
 867                 }
 868         }
 869
 870         //
 871         // Created from the conversion code
 872         //
 873         public class ImplicitDelegateCreation : DelegateCreation {
 874
 875                 ImplicitDelegateCreation (Type t, Location l)
 876                 {
 877                         type = t;
 878                         loc = l;
 879                 }
 880
 881                 public override Expression DoResolve (EmitContext ec)
 882                 {
 883                         return this;
 884                 }
 885
 886                 static public Expression Create (EmitContext ec, MethodGroupExpr mge,
 887                                                  Type target_type, bool check_only, Location loc)
 888                 {
 889                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 890                         if (d.ResolveConstructorMethod (ec))
 891                                 return d.ResolveMethodGroupExpr (ec, mge, check_only);
 892                         else
 893                                 return null;
 894                 }
 895         }
 896
 897         //
 898         // A delegate-creation-expression, invoked from the `New' class
 899         //
 900         public class NewDelegate : DelegateCreation {
 901                 public ArrayList Arguments;
 902
 903                 //
 904                 // This constructor is invoked from the `New' expression
 905                 //
 906                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 907                 {
 908                         this.type = type;
 909                         this.Arguments = Arguments;
 910                         this.loc  = loc;
 911                 }
 912
 913                 public override Expression DoResolve (EmitContext ec)
 914                 {
 915                         if (Arguments == null || Arguments.Count != 1) {
 916                                 Report.Error (149, loc,
 917                                               "Method name expected");
 918                                 return null;
 919                         }
 920
 921                         if (!ResolveConstructorMethod (ec))
 922                                 return null;
 923
 924                         Argument a = (Argument) Arguments [0];
 925
 926                         if (!a.ResolveMethodGroup (ec, loc))
 927                                 return null;
 928
 929                         Expression e = a.Expr;
 930
 931                         if (e is AnonymousMethod && RootContext.Version != LanguageVersion.ISO_1)
 932                                 return ((AnonymousMethod) e).Compatible (ec, type, false);
 933
 934                         MethodGroupExpr mg = e as MethodGroupExpr;
 935                         if (mg != null)
 936                                 return ResolveMethodGroupExpr (ec, mg, false);
 937
 938                         Type e_type = e.Type;
 939
 940                         if (!TypeManager.IsDelegateType (e_type)) {
 941                                 Report.Error (149, loc, "Method name expected");
 942                                 return null;
 943                         }
 944
 945                         method_group = Expression.MemberLookup (
 946                                 ec, type, "Invoke", MemberTypes.Method,
 947                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 948
 949                         if (method_group == null) {
 950                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 951                                 return null;
 952                         }
 953
 954                         // This is what MS' compiler reports. We could always choose
 955                         // to be more verbose and actually give delegate-level specifics
 956                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 957                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 958                                               "to type '" + type + "'");
 959                                 return null;
 960                         }
 961
 962                         delegate_instance_expression = e;
 963                         delegate_method = method_group.Methods [0];
 964
 965                         eclass = ExprClass.Value;
 966                         return this;
 967                 }
 968         }
 969
 970         public class DelegateInvocation : ExpressionStatement {
 971
 972                 public Expression InstanceExpr;
 973                 public ArrayList  Arguments;
 974
 975                 MethodBase method;
 976
 977                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 978                 {
 979                         this.InstanceExpr = instance_expr;
 980                         this.Arguments = args;
 981                         this.loc = loc;
 982                 }
 983
 984                 public override Expression DoResolve (EmitContext ec)
 985                 {
 986                         if (InstanceExpr is EventExpr) {
 987
 988                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 989
 990                                 Expression ml = MemberLookup (
 991                                         ec, ec.ContainerType, ei.Name,
 992                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 993
 994                                 if (ml == null) {
 995                                         //
 996                                         // If this is the case, then the Event does not belong
 997                                         // to this Type and so, according to the spec
 998                                         // cannot be accessed directly
 999                                         //
1000                                         // Note that target will not appear as an EventExpr
1001                                         // in the case it is being referenced within the same type container;
1002                                         // it will appear as a FieldExpr in that case.
1003                                         //
1004
1005                                         Assign.error70 (ei, loc);
1006                                         return null;
1007                                 }
1008                         }
1009
1010
1011                         Type del_type = InstanceExpr.Type;
1012                         if (del_type == null)
1013                                 return null;
1014
1015                         if (Arguments != null){
1016                                 foreach (Argument a in Arguments){
1017                                         if (!a.Resolve (ec, loc))
1018                                                 return null;
1019                                 }
1020                         }
1021
1022                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
1023                                 return null;
1024
1025                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
1026                         if (!(lookup is MethodGroupExpr)) {
1027                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
1028                                 return null;
1029                         }
1030
1031                         method = ((MethodGroupExpr) lookup).Methods [0];
1032                         type = ((MethodInfo) method).ReturnType;
1033                         eclass = ExprClass.Value;
1034
1035                         return this;
1036                 }
1037
1038                 public override void Emit (EmitContext ec)
1039                 {
1040                         //
1041                         // Invocation on delegates call the virtual Invoke member
1042                         // so we are always `instance' calls
1043                         //
1044                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
1045                 }
1046
1047                 public override void EmitStatement (EmitContext ec)
1048                 {
1049                         Emit (ec);
1050                         //
1051                         // Pop the return value if there is one
1052                         //
1053                         if (method is MethodInfo){
1054                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
1055                                         ec.ig.Emit (OpCodes.Pop);
1056                         }
1057                 }
1058
1059         }
1060 }