mcs/gmcs/delegate.cs

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