mcs/mcs/delegate.cs

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