mcs/gmcs/delegate.cs

   1 //
   2 // delegate.cs: Delegate Handler
   3 //
   4 // Authors:
   5 //     Ravi Pratap (ravi@ximian.com)
   6 //     Miguel de Icaza (miguel@ximian.com)
   7 //
   8 // Licensed under the terms of the GNU GPL
   9 //
  10 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  11 //
  12 //
  13
  14 using System;
  15 using System.Collections;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.Text;
  19
  20 namespace Mono.CSharp {
  21
  22         /// <summary>
  23         ///   Holds Delegates
  24         /// </summary>
  25         public class Delegate : DeclSpace {
  26                 public Expression ReturnType;
  27                 public Parameters      Parameters;
  28
  29                 public ConstructorBuilder ConstructorBuilder;
  30                 public MethodBuilder      InvokeBuilder;
  31                 public MethodBuilder      BeginInvokeBuilder;
  32                 public MethodBuilder      EndInvokeBuilder;
  33
  34                 Type [] param_types;
  35                 Type ret_type;
  36
  37                 static string[] attribute_targets = new string [] { "type", "return" };
  38
  39                 Expression instance_expr;
  40                 MethodBase delegate_method;
  41                 ReturnParameter return_attributes;
  42
  43                 const int AllowedModifiers =
  44                         Modifiers.NEW |
  45                         Modifiers.PUBLIC |
  46                         Modifiers.PROTECTED |
  47                         Modifiers.INTERNAL |
  48                         Modifiers.UNSAFE |
  49                         Modifiers.PRIVATE;
  50
  51                 public Delegate (NamespaceEntry ns, TypeContainer parent, Expression type,
  52                                  int mod_flags, MemberName name, Parameters param_list,
  53                                  Attributes attrs, Location l)
  54                         : base (ns, parent, name, attrs, l)
  55
  56                 {
  57                         this.ReturnType = type;
  58                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  59                                                            IsTopLevel ? Modifiers.INTERNAL :
  60                                                            Modifiers.PRIVATE, l);
  61                         Parameters      = param_list;
  62                 }
  63
  64                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  65                 {
  66                         if (a.Target == AttributeTargets.ReturnValue) {
  67                                 if (return_attributes == null)
  68                                         return_attributes = new ReturnParameter (InvokeBuilder, Location);
  69
  70                                 return_attributes.ApplyAttributeBuilder (a, cb);
  71                                 return;
  72                         }
  73
  74                         base.ApplyAttributeBuilder (a, cb);
  75                 }
  76
  77                 public override TypeBuilder DefineType ()
  78                 {
  79                         if (TypeBuilder != null)
  80                                 return TypeBuilder;
  81
  82                         ec = new EmitContext (this, this, Location, null, null, ModFlags, false);
  83
  84                         if (IsGeneric) {
  85                                 foreach (TypeParameter type_param in TypeParameters)
  86                                         if (!type_param.Resolve (this))
  87                                                 return null;
  88                         }
  89
  90                         if (TypeManager.multicast_delegate_type == null && !RootContext.StdLib) {
  91                                 Namespace system = Namespace.LookupNamespace ("System", true);
  92                                 TypeExpr expr = system.Lookup (this, "MulticastDelegate", Location) as TypeExpr;
  93                                 TypeManager.multicast_delegate_type = expr.ResolveType (ec);
  94                         }
  95
  96                         if (TypeManager.multicast_delegate_type == null)
  97                                 Report.Error (-100, Location, "Internal error: delegate used before " +
  98                                               "System.MulticastDelegate is resolved.  This can only " +
  99                                               "happen during corlib compilation, when using a delegate " +
 100                                               "in any of the `core' classes.  See bug #72015 for details.");
 101
 102                         if (IsTopLevel) {
 103                                 if (TypeManager.NamespaceClash (Name, Location))
 104                                         return null;
 105
 106                                 ModuleBuilder builder = CodeGen.Module.Builder;
 107
 108                                 TypeBuilder = builder.DefineType (
 109                                         Name, TypeAttr, TypeManager.multicast_delegate_type);
 110                         } else {
 111                                 TypeBuilder builder = Parent.TypeBuilder;
 112
 113                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
 114                                 TypeBuilder = builder.DefineNestedType (
 115                                         name, TypeAttr, TypeManager.multicast_delegate_type);
 116                         }
 117
 118                         TypeManager.AddDelegateType (Name, TypeBuilder, this);
 119
 120                         if (IsGeneric) {
 121                                 string[] param_names = new string [TypeParameters.Length];
 122                                 for (int i = 0; i < TypeParameters.Length; i++)
 123                                         param_names [i] = TypeParameters [i].Name;
 124
 125                                 GenericTypeParameterBuilder[] gen_params;
 126                                 gen_params = TypeBuilder.DefineGenericParameters (param_names);
 127
 128                                 int offset = CountTypeParameters - CurrentTypeParameters.Length;
 129                                 for (int i = offset; i < gen_params.Length; i++)
 130                                         CurrentTypeParameters [i - offset].Define (gen_params [i]);
 131
 132                                 foreach (TypeParameter type_param in CurrentTypeParameters) {
 133                                         if (!type_param.Resolve (this))
 134                                                 return null;
 135                                 }
 136
 137                                 for (int i = offset; i < gen_params.Length; i++)
 138                                         CurrentTypeParameters [i - offset].DefineConstraints ();
 139
 140                                 Expression current = new SimpleName (Name, TypeParameters, Location);
 141                                 current = current.ResolveAsTypeTerminal (ec);
 142                                 if (current == null)
 143                                         return null;
 144
 145                                 CurrentType = current.Type;
 146                         }
 147
 148                         return TypeBuilder;
 149                 }
 150
 151                 public override bool DefineMembers (TypeContainer container)
 152                 {
 153                         return true;
 154                 }
 155
 156                 public override bool Define ()
 157                 {
 158                         MethodAttributes mattr;
 159                         int i;
 160
 161                         if (IsGeneric) {
 162                                 foreach (TypeParameter type_param in TypeParameters)
 163                                         type_param.DefineType (ec);
 164                         }
 165
 166                         if (ec == null)
 167                                 throw new InternalErrorException ("Define called before DefineType?");
 168
 169                         // FIXME: POSSIBLY make this static, as it is always constant
 170                         //
 171                         Type [] const_arg_types = new Type [2];
 172                         const_arg_types [0] = TypeManager.object_type;
 173                         const_arg_types [1] = TypeManager.intptr_type;
 174
 175                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 176                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 177
 178                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 179                                                                             CallingConventions.Standard,
 180                                                                             const_arg_types);
 181
 182                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 183                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 184                         //
 185                         // HACK because System.Reflection.Emit is lame
 186                         //
 187                         //
 188                         // FIXME: POSSIBLY make these static, as they are always the same
 189                         Parameter [] fixed_pars = new Parameter [2];
 190                         fixed_pars [0] = new Parameter (TypeManager.system_object_expr, "object",
 191                                                         Parameter.Modifier.NONE, null);
 192                         fixed_pars [1] = new Parameter (TypeManager.system_intptr_expr, "method",
 193                                                         Parameter.Modifier.NONE, null);
 194                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);
 195
 196                         TypeManager.RegisterMethod (
 197                                 ConstructorBuilder,
 198                                 new InternalParameters (const_arg_types, const_parameters),
 199                                 const_arg_types);
 200
 201
 202                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 203
 204                         //
 205                         // Here the various methods like Invoke, BeginInvoke etc are defined
 206                         //
 207                         // First, call the `out of band' special method for
 208                         // defining recursively any types we need:
 209
 210                         param_types = Parameters.GetParameterInfo (ec);
 211                         if (param_types == null)
 212                                 return false;
 213
 214                         //
 215                         // Invoke method
 216                         //
 217
 218                         // Check accessibility
 219                         foreach (Type partype in param_types){
 220                                 if (!Parent.AsAccessible (partype, ModFlags)) {
 221                                         Report.Error (59, Location,
 222                                                       "Inconsistent accessibility: parameter type `" +
 223                                                       TypeManager.CSharpName (partype) + "` is less " +
 224                                                       "accessible than delegate `" + Name + "'");
 225                                         return false;
 226                                 }
 227                                 if (partype.IsPointer && !UnsafeOK (Parent))
 228                                         return false;
 229                         }
 230
 231                         ReturnType = ReturnType.ResolveAsTypeTerminal (ec);
 232                         if (ReturnType == null)
 233                             return false;
 234
 235                         ret_type = ReturnType.Type;
 236                         if (ret_type == null)
 237                                 return false;
 238
 239                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 240                                 Report.Error (58, Location,
 241                                               "Inconsistent accessibility: return type `" +
 242                                               TypeManager.CSharpName (ret_type) + "` is less " +
 243                                               "accessible than delegate `" + Name + "'");
 244                                 return false;
 245                         }
 246
 247                         if (ret_type.IsPointer && !UnsafeOK (Parent))
 248                                 return false;
 249
 250                         if (RootContext.StdLib && (ret_type == TypeManager.arg_iterator_type || ret_type == TypeManager.typed_reference_type)) {
 251                                 Method.Error1599 (Location, ret_type);
 252                                 return false;
 253                         }
 254
 255                         //
 256                         // We don't have to check any others because they are all
 257                         // guaranteed to be accessible - they are standard types.
 258                         //
 259
 260                         CallingConventions cc = Parameters.GetCallingConvention ();
 261
 262                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 263
 264                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 265                                                                   mattr,
 266                                                                   cc,
 267                                                                   ret_type,
 268                                                                   param_types);
 269
 270                         //
 271                         // Define parameters, and count out/ref parameters
 272                         //
 273                         int out_params = 0;
 274                         i = 0;
 275                         if (Parameters.FixedParameters != null){
 276                                 int top = Parameters.FixedParameters.Length;
 277                                 Parameter p;
 278
 279                                 for (; i < top; i++) {
 280                                         p = Parameters.FixedParameters [i];
 281                                         p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 282
 283                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 284                                                 out_params++;
 285                                 }
 286                         }
 287                         if (Parameters.ArrayParameter != null){
 288                                 if (TypeManager.param_array_type == null && !RootContext.StdLib) {
 289                                         Namespace system = Namespace.LookupNamespace ("System", true);
 290                                         TypeExpr expr = system.Lookup (this, "ParamArrayAttribute", Location) as TypeExpr;
 291                                         TypeManager.param_array_type = expr.ResolveType (ec);
 292                                 }
 293
 294                                 if (TypeManager.cons_param_array_attribute == null) {
 295                                         Type [] void_arg = { };
 296                                         TypeManager.cons_param_array_attribute = TypeManager.GetConstructor (
 297                                                 TypeManager.param_array_type, void_arg);
 298                                 }
 299
 300                                 ParameterBuilder pb = InvokeBuilder.DefineParameter (
 301                                         i + 1, Parameters.ArrayParameter.Attributes,Parameters.ArrayParameter.Name);
 302
 303                                 pb.SetCustomAttribute (
 304                                         new CustomAttributeBuilder (TypeManager.cons_param_array_attribute, new object [0]));
 305                         }
 306
 307                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 308
 309                         TypeManager.RegisterMethod (InvokeBuilder,
 310                                                     new InternalParameters (param_types, Parameters),
 311                                                     param_types);
 312
 313                         //
 314                         // BeginInvoke
 315                         //
 316                         int params_num = param_types.Length;
 317                         Type [] async_param_types = new Type [params_num + 2];
 318
 319                         param_types.CopyTo (async_param_types, 0);
 320
 321                         async_param_types [params_num] = TypeManager.asynccallback_type;
 322                         async_param_types [params_num + 1] = TypeManager.object_type;
 323
 324                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 325                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 326
 327                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 328                                                                        mattr,
 329                                                                        cc,
 330                                                                        TypeManager.iasyncresult_type,
 331                                                                        async_param_types);
 332
 333                         i = 0;
 334                         if (Parameters.FixedParameters != null){
 335                                 int top = Parameters.FixedParameters.Length;
 336                                 Parameter p;
 337
 338                                 for (i = 0 ; i < top; i++) {
 339                                         p = Parameters.FixedParameters [i];
 340
 341                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 342                                 }
 343                         }
 344                         if (Parameters.ArrayParameter != null){
 345                                 Parameter p = Parameters.ArrayParameter;
 346                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 347
 348                                 i++;
 349                         }
 350
 351                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 352                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 353
 354                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 355
 356                         Parameter [] async_params = new Parameter [params_num + 2];
 357                         int n = 0;
 358                         if (Parameters.FixedParameters != null){
 359                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 360                                 n = Parameters.FixedParameters.Length;
 361                         }
 362                         if (Parameters.ArrayParameter != null)
 363                                 async_params [n] = Parameters.ArrayParameter;
 364
 365                         async_params [params_num] = new Parameter (
 366                                 TypeManager.system_asynccallback_expr, "callback",
 367                                                                    Parameter.Modifier.NONE, null);
 368                         async_params [params_num + 1] = new Parameter (
 369                                 TypeManager.system_object_expr, "object",
 370                                                                    Parameter.Modifier.NONE, null);
 371
 372                         Parameters async_parameters = new Parameters (async_params, null, Location);
 373
 374                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 375                                                     new InternalParameters (async_parameters.GetParameterInfo (ec), async_parameters),
 376                                                     async_param_types);
 377
 378                         //
 379                         // EndInvoke is a bit more interesting, all the parameters labeled as
 380                         // out or ref have to be duplicated here.
 381                         //
 382
 383                         Type [] end_param_types = new Type [out_params + 1];
 384                         Parameter [] end_params = new Parameter [out_params + 1];
 385                         int param = 0;
 386                         if (out_params > 0){
 387                                 int top = Parameters.FixedParameters.Length;
 388                                 for (i = 0; i < top; i++){
 389                                         Parameter p = Parameters.FixedParameters [i];
 390                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 391                                                 continue;
 392
 393                                         end_param_types [param] = param_types [i];
 394                                         end_params [param] = p;
 395                                         param++;
 396                                 }
 397                         }
 398                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 399                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 400
 401                         //
 402                         // Create method, define parameters, register parameters with type system
 403                         //
 404                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 405                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 406
 407                         //
 408                         // EndInvoke: Label the parameters
 409                         //
 410                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 411                         for (i = 0; i < end_params.Length-1; i++){
 412                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 413                         }
 414
 415                         Parameters end_parameters = new Parameters (end_params, null, Location);
 416
 417                         TypeManager.RegisterMethod (
 418                                 EndInvokeBuilder,
 419                                 new InternalParameters (end_parameters.GetParameterInfo (ec), end_parameters),
 420                                 end_param_types);
 421
 422                         return true;
 423                 }
 424
 425                 public override void Emit ()
 426                 {
 427                         if (OptAttributes != null) {
 428                                 Parameters.LabelParameters (ec, InvokeBuilder, Location);
 429                                 OptAttributes.Emit (ec, this);
 430                         }
 431
 432                         base.Emit ();
 433                 }
 434
 435                 protected override TypeAttributes TypeAttr {
 436                         get {
 437                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 438                                         TypeAttributes.Class | TypeAttributes.Sealed |
 439                                         base.TypeAttr;
 440                         }
 441                 }
 442
 443                 public override string[] ValidAttributeTargets {
 444                         get {
 445                                 return attribute_targets;
 446                         }
 447                 }
 448
 449                 //TODO: duplicate
 450                 protected override bool VerifyClsCompliance (DeclSpace ds)
 451                 {
 452                         if (!base.VerifyClsCompliance (ds)) {
 453                                 return false;
 454                         }
 455
 456                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 457
 458                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 459                                 Report.Error (3002, Location, "Return type of '{0}' is not CLS-compliant", GetSignatureForError ());
 460                         }
 461                         return true;
 462                 }
 463
 464                 //
 465                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 466                 // to extract the signature of a delegate.
 467                 //
 468                 public static MethodGroupExpr GetInvokeMethod (EmitContext ec, Type delegate_type,
 469                                                                Location loc)
 470                 {
 471                         Expression ml = Expression.MemberLookup (
 472                                 ec, delegate_type, "Invoke", loc);
 473
 474                         MethodGroupExpr mg = ml as MethodGroupExpr;
 475                         if (mg == null) {
 476                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 477                                 return null;
 478                         }
 479
 480                         return mg;
 481                 }
 482
 483                 /// <summary>
 484                 ///  Verifies whether the method in question is compatible with the delegate
 485                 ///  Returns the method itself if okay and null if not.
 486                 /// </summary>
 487                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type,
 488                                                        MethodGroupExpr old_mg, MethodBase mb,
 489                                                        Location loc)
 490                 {
 491                         MethodGroupExpr mg = GetInvokeMethod (ec, delegate_type, loc);
 492                         if (mg == null)
 493                                 return null;
 494
 495                         if (old_mg.HasTypeArguments)
 496                                 mg.HasTypeArguments = true;
 497
 498                         MethodBase invoke_mb = mg.Methods [0];
 499                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 500
 501                         if (!mg.HasTypeArguments &&
 502                             !TypeManager.InferTypeArguments (ec, invoke_pd, ref mb))
 503                                 return null;
 504
 505                         ParameterData pd = TypeManager.GetParameterData (mb);
 506
 507                         if (invoke_pd.Count != pd.Count)
 508                                 return null;
 509
 510                         for (int i = pd.Count; i > 0; ) {
 511                                 i--;
 512
 513                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 514                                 Type pd_type = pd.ParameterType (i);
 515                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 516                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 517
 518                                 if (invoke_pd_type == pd_type &&
 519                                     invoke_pd_type_mod == pd_type_mod)
 520                                         continue;
 521
 522                                 if (invoke_pd_type.IsSubclassOf (pd_type) &&
 523                                     invoke_pd_type_mod == pd_type_mod)
 524                                         if (RootContext.Version == LanguageVersion.ISO_1) {
 525                                                 Report.FeatureIsNotStandardized (loc, "contravariance");
 526                                                 return null;
 527                                         } else
 528                                                 continue;
 529
 530                                 return null;
 531                         }
 532
 533                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 534                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 535                         if (invoke_mb_retval == mb_retval)
 536                                 return mb;
 537
 538                         if (mb_retval.IsSubclassOf (invoke_mb_retval))
 539                                 if (RootContext.Version == LanguageVersion.ISO_1) {
 540                                         Report.FeatureIsNotStandardized (loc, "covariance");
 541                                         return null;
 542                                 }
 543                                 else
 544                                         return mb;
 545
 546                         return null;
 547                 }
 548
 549                 // <summary>
 550                 //  Verifies whether the invocation arguments are compatible with the
 551                 //  delegate's target method
 552                 // </summary>
 553                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 554                                                         ArrayList args, Location loc)
 555                 {
 556                         int arg_count;
 557
 558                         if (args == null)
 559                                 arg_count = 0;
 560                         else
 561                                 arg_count = args.Count;
 562
 563                         Expression ml = Expression.MemberLookup (
 564                                 ec, delegate_type, "Invoke", loc);
 565
 566                         MethodGroupExpr me = ml as MethodGroupExpr;
 567                         if (me == null) {
 568                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 569                                 return false;
 570                         }
 571
 572                         MethodBase mb = me.Methods [0];
 573                         ParameterData pd = TypeManager.GetParameterData (mb);
 574
 575                         int pd_count = pd.Count;
 576
 577                         bool params_method = (pd_count != 0) &&
 578                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 579
 580                         bool is_params_applicable = false;
 581                         bool is_applicable = Invocation.IsApplicable (ec, me, args, arg_count, ref mb);
 582
 583                         if (!is_applicable && params_method &&
 584                             Invocation.IsParamsMethodApplicable (ec, me, args, arg_count, ref mb))
 585                                 is_applicable = is_params_applicable = true;
 586
 587                         if (!is_applicable && !params_method && arg_count != pd_count) {
 588                                 Report.Error (1593, loc,
 589                                               "Delegate '{0}' does not take {1} arguments",
 590                                               delegate_type.ToString (), arg_count);
 591                                 return false;
 592                         }
 593
 594                         return Invocation.VerifyArgumentsCompat (
 595                                         ec, args, arg_count, mb,
 596                                         is_params_applicable || (!is_applicable && params_method),
 597                                         delegate_type, false, loc);
 598                 }
 599
 600                 /// <summary>
 601                 ///  Verifies whether the delegate in question is compatible with this one in
 602                 ///  order to determine if instantiation from the same is possible.
 603                 /// </summary>
 604                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 605                 {
 606                         Expression ml = Expression.MemberLookup (
 607                                 ec, delegate_type, "Invoke", loc);
 608
 609                         if (!(ml is MethodGroupExpr)) {
 610                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 611                                 return false;
 612                         }
 613
 614                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 615                         ParameterData pd = TypeManager.GetParameterData (mb);
 616
 617                         Expression probe_ml = Expression.MemberLookup (
 618                                 ec, delegate_type, "Invoke", loc);
 619
 620                         if (!(probe_ml is MethodGroupExpr)) {
 621                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 622                                 return false;
 623                         }
 624
 625                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 626                         ParameterData probe_pd = TypeManager.GetParameterData (probe_mb);
 627
 628                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 629                                 return false;
 630
 631                         if (pd.Count != probe_pd.Count)
 632                                 return false;
 633
 634                         for (int i = pd.Count; i > 0; ) {
 635                                 i--;
 636
 637                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 638                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 639                                         return false;
 640                         }
 641
 642                         return true;
 643                 }
 644
 645                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 646                 {
 647                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 648
 649                         sb.Append (" " + del_type.ToString ());
 650                         sb.Append (" (");
 651
 652                         int length = pd.Count;
 653
 654                         for (int i = length; i > 0; ) {
 655                                 i--;
 656
 657                                 sb.Append (pd.ParameterDesc (length - i - 1));
 658                                 if (i != 0)
 659                                         sb.Append (", ");
 660                         }
 661
 662                         sb.Append (")");
 663                         return sb.ToString ();
 664
 665                 }
 666
 667                 // Hack around System.Reflection as found everywhere else
 668                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 669                                                         MemberFilter filter, object criteria)
 670                 {
 671                         ArrayList members = new ArrayList ();
 672
 673                         if ((mt & MemberTypes.Method) != 0) {
 674                                 if (ConstructorBuilder != null)
 675                                 if (filter (ConstructorBuilder, criteria))
 676                                         members.Add (ConstructorBuilder);
 677
 678                                 if (InvokeBuilder != null)
 679                                 if (filter (InvokeBuilder, criteria))
 680                                         members.Add (InvokeBuilder);
 681
 682                                 if (BeginInvokeBuilder != null)
 683                                 if (filter (BeginInvokeBuilder, criteria))
 684                                         members.Add (BeginInvokeBuilder);
 685
 686                                 if (EndInvokeBuilder != null)
 687                                 if (filter (EndInvokeBuilder, criteria))
 688                                         members.Add (EndInvokeBuilder);
 689                         }
 690
 691                         return new MemberList (members);
 692                 }
 693
 694                 public override MemberCache MemberCache {
 695                         get {
 696                                 return null;
 697                         }
 698                 }
 699
 700                 public Expression InstanceExpression {
 701                         get {
 702                                 return instance_expr;
 703                         }
 704                         set {
 705                                 instance_expr = value;
 706                         }
 707                 }
 708
 709                 public MethodBase TargetMethod {
 710                         get {
 711                                 return delegate_method;
 712                         }
 713                         set {
 714                                 delegate_method = value;
 715                         }
 716                 }
 717
 718                 public Type TargetReturnType {
 719                         get {
 720                                 return ret_type;
 721                         }
 722                 }
 723
 724                 public Type [] ParameterTypes {
 725                         get {
 726                                 return param_types;
 727                         }
 728                 }
 729
 730                 public override AttributeTargets AttributeTargets {
 731                         get {
 732                                 return AttributeTargets.Delegate;
 733                         }
 734                 }
 735
 736                 //
 737                 //   Represents header string for documentation comment.
 738                 //
 739                 public override string DocCommentHeader {
 740                         get { return "T:"; }
 741                 }
 742
 743                 protected override void VerifyObsoleteAttribute()
 744                 {
 745                         CheckUsageOfObsoleteAttribute (ret_type);
 746
 747                         foreach (Type type in param_types) {
 748                                 CheckUsageOfObsoleteAttribute (type);
 749                         }
 750                 }
 751         }
 752
 753         //
 754         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 755         //
 756         public abstract class DelegateCreation : Expression {
 757                 protected MethodBase constructor_method;
 758                 protected MethodBase delegate_method;
 759                 protected MethodGroupExpr method_group;
 760                 protected Expression delegate_instance_expression;
 761
 762                 public DelegateCreation () {}
 763
 764                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 765                 {
 766                         string method_desc;
 767                         MethodBase found_method = mg.Methods [0];
 768
 769                         if (mg.Methods.Length > 1)
 770                                 method_desc = found_method.Name;
 771                         else
 772                                 method_desc = Invocation.FullMethodDesc (found_method);
 773
 774                         Expression invoke_method = Expression.MemberLookup (
 775                                 ec, type, "Invoke", MemberTypes.Method,
 776                                 Expression.AllBindingFlags, loc);
 777                         MethodInfo method = ((MethodGroupExpr) invoke_method).Methods [0] as MethodInfo;
 778
 779                         ParameterData param = TypeManager.GetParameterData (method);
 780                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 781
 782                         if (!mg.HasTypeArguments &&
 783                             !TypeManager.InferTypeArguments (ec, param, ref found_method))
 784                                 Report.Error (411, loc, "The type arguments for " +
 785                                               "method `{0}' cannot be infered from " +
 786                                               "the usage. Try specifying the type " +
 787                                               "arguments explicitly.", method_desc);
 788                         else if (method.ReturnType != ((MethodInfo) found_method).ReturnType) {
 789                                 Report.Error (407, loc, "'{0}' has the wrong return type to match delegate '{1}'", method_desc, delegate_desc);
 790                         } else {
 791                                 Report.Error (123, loc, "Method '" + method_desc + "' does not " +
 792                                         "match delegate '" + delegate_desc + "'");
 793                         }
 794                 }
 795
 796                 public override void Emit (EmitContext ec)
 797                 {
 798                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 799                                 ec.ig.Emit (OpCodes.Ldnull);
 800                         else
 801                                 delegate_instance_expression.Emit (ec);
 802
 803                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 804                                 ec.ig.Emit (OpCodes.Dup);
 805                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 806                         } else
 807                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 808                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 809                 }
 810
 811                 protected bool ResolveConstructorMethod (EmitContext ec)
 812                 {
 813                         Expression ml = Expression.MemberLookup (
 814                                 ec, type, ".ctor", loc);
 815
 816                         if (!(ml is MethodGroupExpr)) {
 817                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 818                                 return false;
 819                         }
 820
 821                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 822                         return true;
 823                 }
 824
 825                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg,
 826                                                              bool check_only)
 827                 {
 828                         foreach (MethodInfo mi in mg.Methods){
 829                                 delegate_method  = Delegate.VerifyMethod (ec, type, mg, mi, loc);
 830
 831                                 if (delegate_method != null)
 832                                         break;
 833                         }
 834
 835                         if (delegate_method == null) {
 836                                 if (!check_only)
 837                                         Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 838                                 return null;
 839                         }
 840
 841                         //
 842                         // Check safe/unsafe of the delegate
 843                         //
 844                         if (!ec.InUnsafe){
 845                                 ParameterData param = TypeManager.GetParameterData (delegate_method);
 846                                 int count = param.Count;
 847
 848                                 for (int i = 0; i < count; i++){
 849                                         if (param.ParameterType (i).IsPointer){
 850                                                 Expression.UnsafeError (loc);
 851                                                 return null;
 852                                         }
 853                                 }
 854                         }
 855
 856                         //TODO: implement caching when performance will be low
 857                         IMethodData md = TypeManager.GetMethod (delegate_method);
 858                         if (md == null) {
 859                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 860                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 861                                 }
 862                         } else {
 863                                 md.SetMemberIsUsed ();
 864                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 865                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 866                                 }
 867                         }
 868
 869                         if (mg.InstanceExpression != null)
 870                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 871                         else if (ec.IsStatic) {
 872                                 if (!delegate_method.IsStatic) {
 873                                         Report.Error (120, loc,
 874                                                       "An object reference is required for the non-static method " +
 875                                                       delegate_method.Name);
 876                                         return null;
 877                                 }
 878                                 delegate_instance_expression = null;
 879                         } else
 880                                 delegate_instance_expression = ec.GetThis (loc);
 881
 882                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 883                                 delegate_instance_expression = new BoxedCast (delegate_instance_expression);
 884
 885                         method_group = mg;
 886                         eclass = ExprClass.Value;
 887                         return this;
 888                 }
 889         }
 890
 891         //
 892         // Created from the conversion code
 893         //
 894         public class ImplicitDelegateCreation : DelegateCreation {
 895
 896                 ImplicitDelegateCreation (Type t, Location l)
 897                 {
 898                         type = t;
 899                         loc = l;
 900                 }
 901
 902                 public override Expression DoResolve (EmitContext ec)
 903                 {
 904                         return this;
 905                 }
 906
 907                 static public Expression Create (EmitContext ec, MethodGroupExpr mge,
 908                                                  Type target_type, bool check_only, Location loc)
 909                 {
 910                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 911                         if (d.ResolveConstructorMethod (ec))
 912                                 return d.ResolveMethodGroupExpr (ec, mge, check_only);
 913                         else
 914                                 return null;
 915                 }
 916         }
 917
 918         //
 919         // A delegate-creation-expression, invoked from the `New' class
 920         //
 921         public class NewDelegate : DelegateCreation {
 922                 public ArrayList Arguments;
 923
 924                 //
 925                 // This constructor is invoked from the `New' expression
 926                 //
 927                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 928                 {
 929                         this.type = type;
 930                         this.Arguments = Arguments;
 931                         this.loc  = loc;
 932                 }
 933
 934                 public override Expression DoResolve (EmitContext ec)
 935                 {
 936                         if (Arguments == null || Arguments.Count != 1) {
 937                                 Report.Error (149, loc,
 938                                               "Method name expected");
 939                                 return null;
 940                         }
 941
 942                         if (!ResolveConstructorMethod (ec))
 943                                 return null;
 944
 945                         Argument a = (Argument) Arguments [0];
 946
 947                         if (!a.ResolveMethodGroup (ec, loc))
 948                                 return null;
 949
 950                         Expression e = a.Expr;
 951
 952                         if (e is AnonymousMethod && RootContext.Version != LanguageVersion.ISO_1)
 953                                 return ((AnonymousMethod) e).Compatible (ec, type, false);
 954
 955                         MethodGroupExpr mg = e as MethodGroupExpr;
 956                         if (mg != null)
 957                                 return ResolveMethodGroupExpr (ec, mg, false);
 958
 959                         Type e_type = e.Type;
 960
 961                         if (!TypeManager.IsDelegateType (e_type)) {
 962                                 Report.Error (149, loc, "Method name expected");
 963                                 return null;
 964                         }
 965
 966                         method_group = Expression.MemberLookup (
 967                                 ec, type, "Invoke", MemberTypes.Method,
 968                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 969
 970                         if (method_group == null) {
 971                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 972                                 return null;
 973                         }
 974
 975                         // This is what MS' compiler reports. We could always choose
 976                         // to be more verbose and actually give delegate-level specifics
 977                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 978                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 979                                               "to type '" + type + "'");
 980                                 return null;
 981                         }
 982
 983                         delegate_instance_expression = e;
 984                         delegate_method = method_group.Methods [0];
 985
 986                         eclass = ExprClass.Value;
 987                         return this;
 988                 }
 989         }
 990
 991         public class DelegateInvocation : ExpressionStatement {
 992
 993                 public Expression InstanceExpr;
 994                 public ArrayList  Arguments;
 995
 996                 MethodBase method;
 997
 998                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 999                 {
1000                         this.InstanceExpr = instance_expr;
1001                         this.Arguments = args;
1002                         this.loc = loc;
1003                 }
1004
1005                 public override Expression DoResolve (EmitContext ec)
1006                 {
1007                         if (InstanceExpr is EventExpr) {
1008
1009                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
1010
1011                                 Expression ml = MemberLookup (
1012                                         ec, ec.ContainerType, ei.Name,
1013                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
1014
1015                                 if (ml == null) {
1016                                         //
1017                                         // If this is the case, then the Event does not belong
1018                                         // to this Type and so, according to the spec
1019                                         // cannot be accessed directly
1020                                         //
1021                                         // Note that target will not appear as an EventExpr
1022                                         // in the case it is being referenced within the same type container;
1023                                         // it will appear as a FieldExpr in that case.
1024                                         //
1025
1026                                         Assign.error70 (ei, loc);
1027                                         return null;
1028                                 }
1029                         }
1030
1031
1032                         Type del_type = InstanceExpr.Type;
1033                         if (del_type == null)
1034                                 return null;
1035
1036                         if (Arguments != null){
1037                                 foreach (Argument a in Arguments){
1038                                         if (!a.Resolve (ec, loc))
1039                                                 return null;
1040                                 }
1041                         }
1042
1043                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
1044                                 return null;
1045
1046                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
1047                         if (!(lookup is MethodGroupExpr)) {
1048                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
1049                                 return null;
1050                         }
1051
1052                         method = ((MethodGroupExpr) lookup).Methods [0];
1053                         type = ((MethodInfo) method).ReturnType;
1054                         eclass = ExprClass.Value;
1055
1056                         return this;
1057                 }
1058
1059                 public override void Emit (EmitContext ec)
1060                 {
1061                         //
1062                         // Invocation on delegates call the virtual Invoke member
1063                         // so we are always `instance' calls
1064                         //
1065                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
1066                 }
1067
1068                 public override void EmitStatement (EmitContext ec)
1069                 {
1070                         Emit (ec);
1071                         //
1072                         // Pop the return value if there is one
1073                         //
1074                         if (method is MethodInfo){
1075                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
1076                                         ec.ig.Emit (OpCodes.Pop);
1077                         }
1078                 }
1079
1080         }
1081 }