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