gmcs/delegate.cs

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