mcs/gmcs/delegate.cs

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