mcs/mcs/delegate.cs

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