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