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