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