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                                 Parameter p = Parameters.ArrayParameter;
 289
 290                                 if (TypeManager.param_array_type == null && !RootContext.StdLib) {
 291                                         Namespace system = Namespace.LookupNamespace ("System", true);
 292                                         TypeExpr expr = system.Lookup (this, "ParamArrayAttribute", Location) as TypeExpr;
 293                                         TypeManager.param_array_type = expr.ResolveType (ec);
 294                                 }
 295
 296                                 if (TypeManager.cons_param_array_attribute == null) {
 297                                         Type [] void_arg = { };
 298                                         TypeManager.cons_param_array_attribute = TypeManager.GetConstructor (
 299                                                 TypeManager.param_array_type, void_arg);
 300                                 }
 301
 302                                 ParameterBuilder pb = InvokeBuilder.DefineParameter (
 303                                         i + 1, Parameters.ArrayParameter.Attributes,Parameters.ArrayParameter.Name);
 304
 305                                 pb.SetCustomAttribute (
 306                                         new CustomAttributeBuilder (TypeManager.cons_param_array_attribute, new object [0]));
 307                         }
 308
 309                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 310
 311                         TypeManager.RegisterMethod (InvokeBuilder,
 312                                                     new InternalParameters (param_types, Parameters),
 313                                                     param_types);
 314
 315                         //
 316                         // BeginInvoke
 317                         //
 318                         int params_num = param_types.Length;
 319                         Type [] async_param_types = new Type [params_num + 2];
 320
 321                         param_types.CopyTo (async_param_types, 0);
 322
 323                         async_param_types [params_num] = TypeManager.asynccallback_type;
 324                         async_param_types [params_num + 1] = TypeManager.object_type;
 325
 326                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 327                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 328
 329                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 330                                                                        mattr,
 331                                                                        cc,
 332                                                                        TypeManager.iasyncresult_type,
 333                                                                        async_param_types);
 334
 335                         i = 0;
 336                         if (Parameters.FixedParameters != null){
 337                                 int top = Parameters.FixedParameters.Length;
 338                                 Parameter p;
 339
 340                                 for (i = 0 ; i < top; i++) {
 341                                         p = Parameters.FixedParameters [i];
 342
 343                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 344                                 }
 345                         }
 346                         if (Parameters.ArrayParameter != null){
 347                                 Parameter p = Parameters.ArrayParameter;
 348                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 349
 350                                 i++;
 351                         }
 352
 353                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 354                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 355
 356                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 357
 358                         Parameter [] async_params = new Parameter [params_num + 2];
 359                         int n = 0;
 360                         if (Parameters.FixedParameters != null){
 361                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 362                                 n = Parameters.FixedParameters.Length;
 363                         }
 364                         if (Parameters.ArrayParameter != null)
 365                                 async_params [n] = Parameters.ArrayParameter;
 366
 367                         async_params [params_num] = new Parameter (
 368                                 TypeManager.system_asynccallback_expr, "callback",
 369                                                                    Parameter.Modifier.NONE, null);
 370                         async_params [params_num + 1] = new Parameter (
 371                                 TypeManager.system_object_expr, "object",
 372                                                                    Parameter.Modifier.NONE, null);
 373
 374                         Parameters async_parameters = new Parameters (async_params, null, Location);
 375
 376                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 377                                                     new InternalParameters (async_parameters.GetParameterInfo (ec), async_parameters),
 378                                                     async_param_types);
 379
 380                         //
 381                         // EndInvoke is a bit more interesting, all the parameters labeled as
 382                         // out or ref have to be duplicated here.
 383                         //
 384
 385                         Type [] end_param_types = new Type [out_params + 1];
 386                         Parameter [] end_params = new Parameter [out_params + 1];
 387                         int param = 0;
 388                         if (out_params > 0){
 389                                 int top = Parameters.FixedParameters.Length;
 390                                 for (i = 0; i < top; i++){
 391                                         Parameter p = Parameters.FixedParameters [i];
 392                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 393                                                 continue;
 394
 395                                         end_param_types [param] = param_types [i];
 396                                         end_params [param] = p;
 397                                         param++;
 398                                 }
 399                         }
 400                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 401                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 402
 403                         //
 404                         // Create method, define parameters, register parameters with type system
 405                         //
 406                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 407                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 408
 409                         //
 410                         // EndInvoke: Label the parameters
 411                         //
 412                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 413                         for (i = 0; i < end_params.Length-1; i++){
 414                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 415                         }
 416
 417                         Parameters end_parameters = new Parameters (end_params, null, Location);
 418
 419                         TypeManager.RegisterMethod (
 420                                 EndInvokeBuilder,
 421                                 new InternalParameters (end_parameters.GetParameterInfo (ec), end_parameters),
 422                                 end_param_types);
 423
 424                         return true;
 425                 }
 426
 427                 public override void Emit ()
 428                 {
 429                         if (OptAttributes != null) {
 430                                 Parameters.LabelParameters (ec, InvokeBuilder, Location);
 431                                 OptAttributes.Emit (ec, this);
 432                         }
 433
 434                         base.Emit ();
 435                 }
 436
 437                 protected override TypeAttributes TypeAttr {
 438                         get {
 439                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 440                                         TypeAttributes.Class | TypeAttributes.Sealed |
 441                                         base.TypeAttr;
 442                         }
 443                 }
 444
 445                 public override string[] ValidAttributeTargets {
 446                         get {
 447                                 return attribute_targets;
 448                         }
 449                 }
 450
 451                 //TODO: duplicate
 452                 protected override bool VerifyClsCompliance (DeclSpace ds)
 453                 {
 454                         if (!base.VerifyClsCompliance (ds)) {
 455                                 return false;
 456                         }
 457
 458                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 459
 460                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 461                                 Report.Error (3002, Location, "Return type of '{0}' is not CLS-compliant", GetSignatureForError ());
 462                         }
 463                         return true;
 464                 }
 465
 466                 //
 467                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 468                 // to extract the signature of a delegate.
 469                 //
 470                 public static MethodGroupExpr GetInvokeMethod (EmitContext ec, Type delegate_type,
 471                                                        Location loc)
 472                 {
 473                         Expression ml = Expression.MemberLookup (
 474                                 ec, delegate_type, "Invoke", loc);
 475
 476                         MethodGroupExpr mg = ml as MethodGroupExpr;
 477                         if (mg == null) {
 478                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 479                                 return null;
 480                         }
 481
 482                         return mg;
 483                 }
 484
 485                 /// <summary>
 486                 ///  Verifies whether the method in question is compatible with the delegate
 487                 ///  Returns the method itself if okay and null if not.
 488                 /// </summary>
 489                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 490                                                        Location loc)
 491                 {
 492                         MethodGroupExpr mg = GetInvokeMethod (ec, delegate_type, loc);
 493                         if (mg == null)
 494                                 return null;
 495
 496                         MethodBase invoke_mb = mg.Methods [0];
 497                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 498
 499                         if (!mg.HasTypeArguments &&
 500                             !TypeManager.InferTypeArguments (ec, invoke_pd, ref mb))
 501                                 return null;
 502
 503                         ParameterData pd = TypeManager.GetParameterData (mb);
 504
 505                         if (invoke_pd.Count != pd.Count)
 506                                 return null;
 507
 508                         for (int i = pd.Count; i > 0; ) {
 509                                 i--;
 510
 511                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 512                                 Type pd_type = pd.ParameterType (i);
 513                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 514                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 515
 516                                 if (invoke_pd_type == pd_type &&
 517                                     invoke_pd_type_mod == pd_type_mod)
 518                                         continue;
 519
 520                                 if (invoke_pd_type.IsSubclassOf (pd_type) &&
 521                                                 invoke_pd_type_mod == pd_type_mod)
 522                                         if (RootContext.Version == LanguageVersion.ISO_1) {
 523                                                 Report.FeatureIsNotStandardized (loc, "contravariance");
 524                                                 return null;
 525                                         } else
 526                                                 continue;
 527
 528                                 return null;
 529                         }
 530
 531                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 532                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 533                         if (invoke_mb_retval == mb_retval)
 534                                 return mb;
 535
 536                         if (mb_retval.IsSubclassOf (invoke_mb_retval))
 537                                 if (RootContext.Version == LanguageVersion.ISO_1) {
 538                                         Report.FeatureIsNotStandardized (loc, "covariance");
 539                                         return null;
 540                                 }
 541                                 else
 542                                         return mb;
 543
 544                         return null;
 545                 }
 546
 547                 // <summary>
 548                 //  Verifies whether the invocation arguments are compatible with the
 549                 //  delegate's target method
 550                 // </summary>
 551                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 552                                                         ArrayList args, Location loc)
 553                 {
 554                         int arg_count;
 555
 556                         if (args == null)
 557                                 arg_count = 0;
 558                         else
 559                                 arg_count = args.Count;
 560
 561                         Expression ml = Expression.MemberLookup (
 562                                 ec, delegate_type, "Invoke", loc);
 563
 564                         MethodGroupExpr me = ml as MethodGroupExpr;
 565                         if (me == null) {
 566                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 567                                 return false;
 568                         }
 569
 570                         MethodBase mb = me.Methods [0];
 571                         ParameterData pd = TypeManager.GetParameterData (mb);
 572
 573                         int pd_count = pd.Count;
 574
 575                         bool params_method = (pd_count != 0) &&
 576                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 577
 578                         bool is_params_applicable = false;
 579                         bool is_applicable = Invocation.IsApplicable (ec, me, args, arg_count, ref mb);
 580
 581                         if (!is_applicable && params_method &&
 582                             Invocation.IsParamsMethodApplicable (ec, me, args, arg_count, ref mb))
 583                                 is_applicable = is_params_applicable = true;
 584
 585                         if (!is_applicable && !params_method && arg_count != pd_count) {
 586                                 Report.Error (1593, loc,
 587                                               "Delegate '{0}' does not take {1} arguments",
 588                                               delegate_type.ToString (), arg_count);
 589                                 return false;
 590                         }
 591
 592                         return Invocation.VerifyArgumentsCompat (
 593                                         ec, args, arg_count, mb,
 594                                         is_params_applicable || (!is_applicable && params_method),
 595                                         delegate_type, false, loc);
 596                 }
 597
 598                 /// <summary>
 599                 ///  Verifies whether the delegate in question is compatible with this one in
 600                 ///  order to determine if instantiation from the same is possible.
 601                 /// </summary>
 602                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 603                 {
 604                         Expression ml = Expression.MemberLookup (
 605                                 ec, delegate_type, "Invoke", loc);
 606
 607                         if (!(ml is MethodGroupExpr)) {
 608                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 609                                 return false;
 610                         }
 611
 612                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 613                         ParameterData pd = TypeManager.GetParameterData (mb);
 614
 615                         Expression probe_ml = Expression.MemberLookup (
 616                                 ec, delegate_type, "Invoke", loc);
 617
 618                         if (!(probe_ml is MethodGroupExpr)) {
 619                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 620                                 return false;
 621                         }
 622
 623                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 624                         ParameterData probe_pd = TypeManager.GetParameterData (probe_mb);
 625
 626                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 627                                 return false;
 628
 629                         if (pd.Count != probe_pd.Count)
 630                                 return false;
 631
 632                         for (int i = pd.Count; i > 0; ) {
 633                                 i--;
 634
 635                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 636                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 637                                         return false;
 638                         }
 639
 640                         return true;
 641                 }
 642
 643                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 644                 {
 645                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 646
 647                         sb.Append (" " + del_type.ToString ());
 648                         sb.Append (" (");
 649
 650                         int length = pd.Count;
 651
 652                         for (int i = length; i > 0; ) {
 653                                 i--;
 654
 655                                 sb.Append (pd.ParameterDesc (length - i - 1));
 656                                 if (i != 0)
 657                                         sb.Append (", ");
 658                         }
 659
 660                         sb.Append (")");
 661                         return sb.ToString ();
 662
 663                 }
 664
 665                 // Hack around System.Reflection as found everywhere else
 666                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 667                                                         MemberFilter filter, object criteria)
 668                 {
 669                         ArrayList members = new ArrayList ();
 670
 671                         if ((mt & MemberTypes.Method) != 0) {
 672                                 if (ConstructorBuilder != null)
 673                                 if (filter (ConstructorBuilder, criteria))
 674                                         members.Add (ConstructorBuilder);
 675
 676                                 if (InvokeBuilder != null)
 677                                 if (filter (InvokeBuilder, criteria))
 678                                         members.Add (InvokeBuilder);
 679
 680                                 if (BeginInvokeBuilder != null)
 681                                 if (filter (BeginInvokeBuilder, criteria))
 682                                         members.Add (BeginInvokeBuilder);
 683
 684                                 if (EndInvokeBuilder != null)
 685                                 if (filter (EndInvokeBuilder, criteria))
 686                                         members.Add (EndInvokeBuilder);
 687                         }
 688
 689                         return new MemberList (members);
 690                 }
 691
 692                 public override MemberCache MemberCache {
 693                         get {
 694                                 return null;
 695                         }
 696                 }
 697
 698                 public Expression InstanceExpression {
 699                         get {
 700                                 return instance_expr;
 701                         }
 702                         set {
 703                                 instance_expr = value;
 704                         }
 705                 }
 706
 707                 public MethodBase TargetMethod {
 708                         get {
 709                                 return delegate_method;
 710                         }
 711                         set {
 712                                 delegate_method = value;
 713                         }
 714                 }
 715
 716                 public Type TargetReturnType {
 717                         get {
 718                                 return ret_type;
 719                         }
 720                 }
 721
 722                 public Type [] ParameterTypes {
 723                         get {
 724                                 return param_types;
 725                         }
 726                 }
 727
 728                 public override AttributeTargets AttributeTargets {
 729                         get {
 730                                 return AttributeTargets.Delegate;
 731                         }
 732                 }
 733
 734                 //
 735                 //   Represents header string for documentation comment.
 736                 //
 737                 public override string DocCommentHeader {
 738                         get { return "T:"; }
 739                 }
 740
 741                 protected override void VerifyObsoleteAttribute()
 742                 {
 743                         CheckUsageOfObsoleteAttribute (ret_type);
 744
 745                         foreach (Type type in param_types) {
 746                                 CheckUsageOfObsoleteAttribute (type);
 747                         }
 748                 }
 749         }
 750
 751         //
 752         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 753         //
 754         public abstract class DelegateCreation : Expression {
 755                 protected MethodBase constructor_method;
 756                 protected MethodBase delegate_method;
 757                 protected MethodGroupExpr method_group;
 758                 protected Expression delegate_instance_expression;
 759
 760                 public DelegateCreation () {}
 761
 762                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 763                 {
 764                         string method_desc;
 765                         MethodBase found_method = mg.Methods [0];
 766
 767                         if (mg.Methods.Length > 1)
 768                                 method_desc = found_method.Name;
 769                         else
 770                                 method_desc = Invocation.FullMethodDesc (found_method);
 771
 772                         Expression invoke_method = Expression.MemberLookup (
 773                                 ec, type, "Invoke", MemberTypes.Method,
 774                                 Expression.AllBindingFlags, loc);
 775                         MethodInfo method = ((MethodGroupExpr) invoke_method).Methods [0] as MethodInfo;
 776
 777                         ParameterData param = TypeManager.GetParameterData (method);
 778                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 779
 780                         if (!mg.HasTypeArguments &&
 781                             !TypeManager.InferTypeArguments (ec, param, ref found_method))
 782                                 Report.Error (411, loc, "The type arguments for " +
 783                                               "method `{0}' cannot be infered from " +
 784                                               "the usage. Try specifying the type " +
 785                                               "arguments explicitly.", method_desc);
 786                         else if (method.ReturnType != ((MethodInfo) found_method).ReturnType) {
 787                                 Report.Error (407, loc, "'{0}' has the wrong return type to match delegate '{1}'", method_desc, delegate_desc);
 788                         } else {
 789                                 Report.Error (123, loc, "Method '" + method_desc + "' does not " +
 790                                         "match delegate '" + delegate_desc + "'");
 791                         }
 792                 }
 793
 794                 public override void Emit (EmitContext ec)
 795                 {
 796                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 797                                 ec.ig.Emit (OpCodes.Ldnull);
 798                         else
 799                                 delegate_instance_expression.Emit (ec);
 800
 801                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 802                                 ec.ig.Emit (OpCodes.Dup);
 803                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 804                         } else
 805                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 806                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 807                 }
 808
 809                 protected bool ResolveConstructorMethod (EmitContext ec)
 810                 {
 811                         Expression ml = Expression.MemberLookup (
 812                                 ec, type, ".ctor", loc);
 813
 814                         if (!(ml is MethodGroupExpr)) {
 815                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 816                                 return false;
 817                         }
 818
 819                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 820                         return true;
 821                 }
 822
 823                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 824                 {
 825                         foreach (MethodInfo mi in mg.Methods){
 826                                 delegate_method  = Delegate.VerifyMethod (ec, type, mi, loc);
 827
 828                                 if (delegate_method != null)
 829                                         break;
 830                         }
 831
 832                         if (delegate_method == null) {
 833                                 Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 834                                 return null;
 835                         }
 836
 837                         //
 838                         // Check safe/unsafe of the delegate
 839                         //
 840                         if (!ec.InUnsafe){
 841                                 ParameterData param = TypeManager.GetParameterData (delegate_method);
 842                                 int count = param.Count;
 843
 844                                 for (int i = 0; i < count; i++){
 845                                         if (param.ParameterType (i).IsPointer){
 846                                                 Expression.UnsafeError (loc);
 847                                                 return null;
 848                                         }
 849                                 }
 850                         }
 851
 852                         //TODO: implement caching when performance will be low
 853                         IMethodData md = TypeManager.GetMethod (delegate_method);
 854                         if (md == null) {
 855                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 856                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 857                                 }
 858                         } else {
 859                                 md.SetMemberIsUsed ();
 860                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 861                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 862                                 }
 863                         }
 864
 865                         if (mg.InstanceExpression != null)
 866                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 867                         else if (ec.IsStatic) {
 868                                 if (!delegate_method.IsStatic) {
 869                                         Report.Error (120, loc,
 870                                                       "An object reference is required for the non-static method " +
 871                                                       delegate_method.Name);
 872                                         return null;
 873                                 }
 874                                 delegate_instance_expression = null;
 875                         } else
 876                                 delegate_instance_expression = ec.GetThis (loc);
 877
 878                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 879                                 delegate_instance_expression = new BoxedCast (delegate_instance_expression);
 880
 881                         method_group = mg;
 882                         eclass = ExprClass.Value;
 883                         return this;
 884                 }
 885         }
 886
 887         //
 888         // Created from the conversion code
 889         //
 890         public class ImplicitDelegateCreation : DelegateCreation {
 891
 892                 ImplicitDelegateCreation (Type t, Location l)
 893                 {
 894                         type = t;
 895                         loc = l;
 896                 }
 897
 898                 public override Expression DoResolve (EmitContext ec)
 899                 {
 900                         return this;
 901                 }
 902
 903                 static public Expression Create (EmitContext ec, MethodGroupExpr mge, Type target_type, Location loc)
 904                 {
 905                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 906                         if (d.ResolveConstructorMethod (ec))
 907                                 return d.ResolveMethodGroupExpr (ec, mge);
 908                         else
 909                                 return null;
 910                 }
 911         }
 912
 913         //
 914         // A delegate-creation-expression, invoked from the `New' class
 915         //
 916         public class NewDelegate : DelegateCreation {
 917                 public ArrayList Arguments;
 918
 919                 //
 920                 // This constructor is invoked from the `New' expression
 921                 //
 922                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 923                 {
 924                         this.type = type;
 925                         this.Arguments = Arguments;
 926                         this.loc  = loc;
 927                 }
 928
 929                 public override Expression DoResolve (EmitContext ec)
 930                 {
 931                         if (Arguments == null || Arguments.Count != 1) {
 932                                 Report.Error (149, loc,
 933                                               "Method name expected");
 934                                 return null;
 935                         }
 936
 937                         if (!ResolveConstructorMethod (ec))
 938                                 return null;
 939
 940                         Argument a = (Argument) Arguments [0];
 941
 942                         if (!a.ResolveMethodGroup (ec, loc))
 943                                 return null;
 944
 945                         Expression e = a.Expr;
 946
 947                         if (e is AnonymousMethod && RootContext.Version != LanguageVersion.ISO_1)
 948                                 return ((AnonymousMethod) e).Compatible (ec, type, false);
 949
 950                         MethodGroupExpr mg = e as MethodGroupExpr;
 951                         if (mg != null)
 952                                 return ResolveMethodGroupExpr (ec, mg);
 953
 954                         Type e_type = e.Type;
 955
 956                         if (!TypeManager.IsDelegateType (e_type)) {
 957                                 Report.Error (149, loc, "Method name expected");
 958                                 return null;
 959                         }
 960
 961                         method_group = Expression.MemberLookup (
 962                                 ec, type, "Invoke", MemberTypes.Method,
 963                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 964
 965                         if (method_group == null) {
 966                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 967                                 return null;
 968                         }
 969
 970                         // This is what MS' compiler reports. We could always choose
 971                         // to be more verbose and actually give delegate-level specifics
 972                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 973                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 974                                               "to type '" + type + "'");
 975                                 return null;
 976                         }
 977
 978                         delegate_instance_expression = e;
 979                         delegate_method = method_group.Methods [0];
 980
 981                         eclass = ExprClass.Value;
 982                         return this;
 983                 }
 984         }
 985
 986         public class DelegateInvocation : ExpressionStatement {
 987
 988                 public Expression InstanceExpr;
 989                 public ArrayList  Arguments;
 990
 991                 MethodBase method;
 992
 993                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 994                 {
 995                         this.InstanceExpr = instance_expr;
 996                         this.Arguments = args;
 997                         this.loc = loc;
 998                 }
 999
1000                 public override Expression DoResolve (EmitContext ec)
1001                 {
1002                         if (InstanceExpr is EventExpr) {
1003
1004                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
1005
1006                                 Expression ml = MemberLookup (
1007                                         ec, ec.ContainerType, ei.Name,
1008                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
1009
1010                                 if (ml == null) {
1011                                         //
1012                                         // If this is the case, then the Event does not belong
1013                                         // to this Type and so, according to the spec
1014                                         // cannot be accessed directly
1015                                         //
1016                                         // Note that target will not appear as an EventExpr
1017                                         // in the case it is being referenced within the same type container;
1018                                         // it will appear as a FieldExpr in that case.
1019                                         //
1020
1021                                         Assign.error70 (ei, loc);
1022                                         return null;
1023                                 }
1024                         }
1025
1026
1027                         Type del_type = InstanceExpr.Type;
1028                         if (del_type == null)
1029                                 return null;
1030
1031                         if (Arguments != null){
1032                                 foreach (Argument a in Arguments){
1033                                         if (!a.Resolve (ec, loc))
1034                                                 return null;
1035                                 }
1036                         }
1037
1038                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
1039                                 return null;
1040
1041                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
1042                         if (!(lookup is MethodGroupExpr)) {
1043                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
1044                                 return null;
1045                         }
1046
1047                         method = ((MethodGroupExpr) lookup).Methods [0];
1048                         type = ((MethodInfo) method).ReturnType;
1049                         eclass = ExprClass.Value;
1050
1051                         return this;
1052                 }
1053
1054                 public override void Emit (EmitContext ec)
1055                 {
1056                         //
1057                         // Invocation on delegates call the virtual Invoke member
1058                         // so we are always `instance' calls
1059                         //
1060                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
1061                 }
1062
1063                 public override void EmitStatement (EmitContext ec)
1064                 {
1065                         Emit (ec);
1066                         //
1067                         // Pop the return value if there is one
1068                         //
1069                         if (method is MethodInfo){
1070                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
1071                                         ec.ig.Emit (OpCodes.Pop);
1072                         }
1073                 }
1074
1075         }
1076 }