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                         //
 256                         // We don't have to check any others because they are all
 257                         // guaranteed to be accessible - they are standard types.
 258                         //
 259
 260                         CallingConventions cc = Parameters.GetCallingConvention ();
 261
 262                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 263
 264                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 265                                                                   mattr,
 266                                                                   cc,
 267                                                                   ret_type,
 268                                                                   param_types);
 269
 270                         //
 271                         // Define parameters, and count out/ref parameters
 272                         //
 273                         int out_params = 0;
 274                         i = 0;
 275                         if (Parameters.FixedParameters != null){
 276                                 int top = Parameters.FixedParameters.Length;
 277                                 Parameter p;
 278
 279                                 for (; i < top; i++) {
 280                                         p = Parameters.FixedParameters [i];
 281                                         p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 282
 283                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 284                                                 out_params++;
 285                                 }
 286                         }
 287                         if (Parameters.ArrayParameter != null){
 288                                 Parameter p = Parameters.ArrayParameter;
 289                                 p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 290                         }
 291
 292                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 293
 294                         TypeManager.RegisterMethod (InvokeBuilder,
 295                                                     new InternalParameters (param_types, Parameters),
 296                                                     param_types);
 297
 298                         //
 299                         // BeginInvoke
 300                         //
 301                         int params_num = param_types.Length;
 302                         Type [] async_param_types = new Type [params_num + 2];
 303
 304                         param_types.CopyTo (async_param_types, 0);
 305
 306                         async_param_types [params_num] = TypeManager.asynccallback_type;
 307                         async_param_types [params_num + 1] = TypeManager.object_type;
 308
 309                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 310                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 311
 312                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 313                                                                        mattr,
 314                                                                        cc,
 315                                                                        TypeManager.iasyncresult_type,
 316                                                                        async_param_types);
 317
 318                         i = 0;
 319                         if (Parameters.FixedParameters != null){
 320                                 int top = Parameters.FixedParameters.Length;
 321                                 Parameter p;
 322
 323                                 for (i = 0 ; i < top; i++) {
 324                                         p = Parameters.FixedParameters [i];
 325
 326                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 327                                 }
 328                         }
 329                         if (Parameters.ArrayParameter != null){
 330                                 Parameter p = Parameters.ArrayParameter;
 331                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 332
 333                                 i++;
 334                         }
 335
 336                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 337                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 338
 339                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 340
 341                         Parameter [] async_params = new Parameter [params_num + 2];
 342                         int n = 0;
 343                         if (Parameters.FixedParameters != null){
 344                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 345                                 n = Parameters.FixedParameters.Length;
 346                         }
 347                         if (Parameters.ArrayParameter != null)
 348                                 async_params [n] = Parameters.ArrayParameter;
 349
 350                         async_params [params_num] = new Parameter (
 351                                 TypeManager.system_asynccallback_expr, "callback",
 352                                                                    Parameter.Modifier.NONE, null);
 353                         async_params [params_num + 1] = new Parameter (
 354                                 TypeManager.system_object_expr, "object",
 355                                                                    Parameter.Modifier.NONE, null);
 356
 357                         Parameters async_parameters = new Parameters (async_params, null, Location);
 358                         async_parameters.ComputeAndDefineParameterTypes (ec);
 359
 360                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 361                                                     new InternalParameters (async_param_types, async_parameters),
 362                                                     async_param_types);
 363
 364                         //
 365                         // EndInvoke is a bit more interesting, all the parameters labeled as
 366                         // out or ref have to be duplicated here.
 367                         //
 368
 369                         Type [] end_param_types = new Type [out_params + 1];
 370                         Parameter [] end_params = new Parameter [out_params + 1];
 371                         int param = 0;
 372                         if (out_params > 0){
 373                                 int top = Parameters.FixedParameters.Length;
 374                                 for (i = 0; i < top; i++){
 375                                         Parameter p = Parameters.FixedParameters [i];
 376                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 377                                                 continue;
 378
 379                                         end_param_types [param] = param_types [i];
 380                                         end_params [param] = p;
 381                                         param++;
 382                                 }
 383                         }
 384                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 385                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 386
 387                         //
 388                         // Create method, define parameters, register parameters with type system
 389                         //
 390                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 391                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 392
 393                         //
 394                         // EndInvoke: Label the parameters
 395                         //
 396                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 397                         for (i = 0; i < end_params.Length-1; i++){
 398                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 399                         }
 400
 401                         Parameters end_parameters = new Parameters (end_params, null, Location);
 402                         end_parameters.ComputeAndDefineParameterTypes (ec);
 403
 404                         TypeManager.RegisterMethod (
 405                                 EndInvokeBuilder,
 406                                 new InternalParameters (end_param_types, end_parameters),
 407                                 end_param_types);
 408
 409                         return true;
 410                 }
 411
 412                 public override void Emit ()
 413                 {
 414                         if (OptAttributes != null) {
 415                                 Parameters.LabelParameters (ec, InvokeBuilder, Location);
 416                                 OptAttributes.Emit (ec, this);
 417                         }
 418
 419                         base.Emit ();
 420                 }
 421
 422                 public override string[] ValidAttributeTargets {
 423                         get {
 424                                 return attribute_targets;
 425                         }
 426                 }
 427
 428                 //TODO: duplicate
 429                 protected override bool VerifyClsCompliance (DeclSpace ds)
 430                 {
 431                         if (!base.VerifyClsCompliance (ds)) {
 432                                 return false;
 433                         }
 434
 435                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 436
 437                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 438                                 Report.Error (3002, Location, "Return type of '{0}' is not CLS-compliant", GetSignatureForError ());
 439                         }
 440                         return true;
 441                 }
 442
 443                 //
 444                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 445                 // to extract the signature of a delegate.
 446                 //
 447                 public static MethodGroupExpr GetInvokeMethod (EmitContext ec, Type delegate_type,
 448                                                        Location loc)
 449                 {
 450                         Expression ml = Expression.MemberLookup (
 451                                 ec, delegate_type, "Invoke", loc);
 452
 453                         MethodGroupExpr mg = ml as MethodGroupExpr;
 454                         if (mg == null) {
 455                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 456                                 return null;
 457                         }
 458
 459                         return mg;
 460                 }
 461
 462                 /// <summary>
 463                 ///  Verifies whether the method in question is compatible with the delegate
 464                 ///  Returns the method itself if okay and null if not.
 465                 /// </summary>
 466                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 467                                                        Location loc)
 468                 {
 469                         MethodGroupExpr mg = GetInvokeMethod (ec, delegate_type, loc);
 470                         if (mg == null)
 471                                 return null;
 472
 473                         MethodBase invoke_mb = mg.Methods [0];
 474                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 475
 476                         if (!mg.HasTypeArguments &&
 477                             !TypeManager.InferTypeArguments (ec, invoke_pd, ref mb))
 478                                 return null;
 479
 480                         ParameterData pd = TypeManager.GetParameterData (mb);
 481
 482                         if (invoke_pd.Count != pd.Count)
 483                                 return null;
 484
 485                         for (int i = pd.Count; i > 0; ) {
 486                                 i--;
 487
 488                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 489                                 Type pd_type = pd.ParameterType (i);
 490                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 491                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 492
 493                                 if (invoke_pd_type == pd_type &&
 494                                     invoke_pd_type_mod == pd_type_mod)
 495                                         continue;
 496
 497                                 if (invoke_pd_type.IsSubclassOf (pd_type) &&
 498                                                 invoke_pd_type_mod == pd_type_mod)
 499                                         if (RootContext.Version == LanguageVersion.ISO_1) {
 500                                                 Report.FeatureIsNotStandardized (loc, "contravariance");
 501                                                 return null;
 502                                         } else
 503                                                 continue;
 504
 505                                 return null;
 506                         }
 507
 508                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 509                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 510                         if (invoke_mb_retval == mb_retval)
 511                                 return mb;
 512
 513                         if (mb_retval.IsSubclassOf (invoke_mb_retval))
 514                                 if (RootContext.Version == LanguageVersion.ISO_1) {
 515                                         Report.FeatureIsNotStandardized (loc, "covariance");
 516                                         return null;
 517                                 }
 518                                 else
 519                                         return mb;
 520
 521                         return null;
 522                 }
 523
 524                 // <summary>
 525                 //  Verifies whether the invocation arguments are compatible with the
 526                 //  delegate's target method
 527                 // </summary>
 528                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 529                                                         ArrayList args, Location loc)
 530                 {
 531                         int arg_count;
 532
 533                         if (args == null)
 534                                 arg_count = 0;
 535                         else
 536                                 arg_count = args.Count;
 537
 538                         Expression ml = Expression.MemberLookup (
 539                                 ec, delegate_type, "Invoke", loc);
 540
 541                         if (!(ml is MethodGroupExpr)) {
 542                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 543                                 return false;
 544                         }
 545
 546                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 547                         ParameterData pd = TypeManager.GetParameterData (mb);
 548
 549                         int pd_count = pd.Count;
 550
 551                         bool params_method = (pd_count != 0) &&
 552                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 553
 554                         if (!params_method && pd_count != arg_count) {
 555                                 Report.Error (1593, loc,
 556                                               "Delegate '{0}' does not take {1} arguments",
 557                                               delegate_type.ToString (), arg_count);
 558                                 return false;
 559                         }
 560
 561                         //
 562                         // Consider the case:
 563                         //   delegate void FOO(param object[] args);
 564                         //   FOO f = new FOO(...);
 565                         //   f(new object[] {1, 2, 3});
 566                         //
 567                         // This should be treated like f(1,2,3).  This is done by ignoring the
 568                         // 'param' modifier for that invocation.  If that fails, then the
 569                         // 'param' modifier is considered.
 570                         //
 571                         // One issue is that 'VerifyArgumentsCompat' modifies the elements of
 572                         // the 'args' array.  However, the modifications appear idempotent.
 573                         // Normal 'Invocation's also have the same behaviour, implicitly.
 574                         //
 575
 576                         bool ans = false;
 577                         if (arg_count == pd_count)
 578                                 ans = Invocation.VerifyArgumentsCompat (
 579                                         ec, args, arg_count, mb, false,
 580                                         delegate_type, false, loc);
 581                         if (!ans && params_method)
 582                                 ans = Invocation.VerifyArgumentsCompat (
 583                                         ec, args, arg_count, mb, true,
 584                                         delegate_type, false, loc);
 585                         return ans;
 586                 }
 587
 588                 /// <summary>
 589                 ///  Verifies whether the delegate in question is compatible with this one in
 590                 ///  order to determine if instantiation from the same is possible.
 591                 /// </summary>
 592                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 593                 {
 594                         Expression ml = Expression.MemberLookup (
 595                                 ec, delegate_type, "Invoke", loc);
 596
 597                         if (!(ml is MethodGroupExpr)) {
 598                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 599                                 return false;
 600                         }
 601
 602                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 603                         ParameterData pd = TypeManager.GetParameterData (mb);
 604
 605                         Expression probe_ml = Expression.MemberLookup (
 606                                 ec, delegate_type, "Invoke", loc);
 607
 608                         if (!(probe_ml is MethodGroupExpr)) {
 609                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 610                                 return false;
 611                         }
 612
 613                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 614                         ParameterData probe_pd = TypeManager.GetParameterData (probe_mb);
 615
 616                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 617                                 return false;
 618
 619                         if (pd.Count != probe_pd.Count)
 620                                 return false;
 621
 622                         for (int i = pd.Count; i > 0; ) {
 623                                 i--;
 624
 625                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 626                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 627                                         return false;
 628                         }
 629
 630                         return true;
 631                 }
 632
 633                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 634                 {
 635                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 636
 637                         sb.Append (" " + del_type.ToString ());
 638                         sb.Append (" (");
 639
 640                         int length = pd.Count;
 641
 642                         for (int i = length; i > 0; ) {
 643                                 i--;
 644
 645                                 sb.Append (pd.ParameterDesc (length - i - 1));
 646                                 if (i != 0)
 647                                         sb.Append (", ");
 648                         }
 649
 650                         sb.Append (")");
 651                         return sb.ToString ();
 652
 653                 }
 654
 655                 // Hack around System.Reflection as found everywhere else
 656                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 657                                                         MemberFilter filter, object criteria)
 658                 {
 659                         ArrayList members = new ArrayList ();
 660
 661                         if ((mt & MemberTypes.Method) != 0) {
 662                                 if (ConstructorBuilder != null)
 663                                 if (filter (ConstructorBuilder, criteria))
 664                                         members.Add (ConstructorBuilder);
 665
 666                                 if (InvokeBuilder != null)
 667                                 if (filter (InvokeBuilder, criteria))
 668                                         members.Add (InvokeBuilder);
 669
 670                                 if (BeginInvokeBuilder != null)
 671                                 if (filter (BeginInvokeBuilder, criteria))
 672                                         members.Add (BeginInvokeBuilder);
 673
 674                                 if (EndInvokeBuilder != null)
 675                                 if (filter (EndInvokeBuilder, criteria))
 676                                         members.Add (EndInvokeBuilder);
 677                         }
 678
 679                         return new MemberList (members);
 680                 }
 681
 682                 public override MemberCache MemberCache {
 683                         get {
 684                                 return null;
 685                         }
 686                 }
 687
 688                 public Expression InstanceExpression {
 689                         get {
 690                                 return instance_expr;
 691                         }
 692                         set {
 693                                 instance_expr = value;
 694                         }
 695                 }
 696
 697                 public MethodBase TargetMethod {
 698                         get {
 699                                 return delegate_method;
 700                         }
 701                         set {
 702                                 delegate_method = value;
 703                         }
 704                 }
 705
 706                 public Type TargetReturnType {
 707                         get {
 708                                 return ret_type;
 709                         }
 710                 }
 711
 712                 public Type [] ParameterTypes {
 713                         get {
 714                                 return param_types;
 715                         }
 716                 }
 717
 718                 public override AttributeTargets AttributeTargets {
 719                         get {
 720                                 return AttributeTargets.Delegate;
 721                         }
 722                 }
 723
 724                 //
 725                 //   Represents header string for documentation comment.
 726                 //
 727                 public override string DocCommentHeader {
 728                         get { return "T:"; }
 729                 }
 730
 731                 protected override void VerifyObsoleteAttribute()
 732                 {
 733                         CheckUsageOfObsoleteAttribute (ret_type);
 734
 735                         foreach (Type type in param_types) {
 736                                 CheckUsageOfObsoleteAttribute (type);
 737                         }
 738                 }
 739         }
 740
 741         //
 742         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 743         //
 744         public abstract class DelegateCreation : Expression {
 745                 protected MethodBase constructor_method;
 746                 protected MethodBase delegate_method;
 747                 protected MethodGroupExpr method_group;
 748                 protected Expression delegate_instance_expression;
 749
 750                 public DelegateCreation () {}
 751
 752                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 753                 {
 754                         string method_desc;
 755
 756                         MethodBase candidate = mg.Methods [0];
 757                         if (mg.Methods.Length > 1)
 758                                 method_desc = candidate.Name;
 759                         else
 760                                 method_desc = Invocation.FullMethodDesc (candidate);
 761
 762                         Expression invoke_method = Expression.MemberLookup (
 763                                 ec, type, "Invoke", MemberTypes.Method,
 764                                 Expression.AllBindingFlags, loc);
 765                         MethodBase method = ((MethodGroupExpr) invoke_method).Methods [0];
 766                         ParameterData param = TypeManager.GetParameterData (method);
 767                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 768
 769                         if (!mg.HasTypeArguments &&
 770                             !TypeManager.InferTypeArguments (ec, param, ref candidate))
 771                                 Report.Error (411, loc, "The type arguments for " +
 772                                               "method `{0}' cannot be infered from " +
 773                                               "the usage. Try specifying the type " +
 774                                               "arguments explicitly.", method_desc);
 775                         else
 776                                 Report.Error (123, loc, "Method '{0}' does not " +
 777                                               "match delegate '{1}'", method_desc,
 778                                               delegate_desc);
 779                 }
 780
 781                 public override void Emit (EmitContext ec)
 782                 {
 783                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 784                                 ec.ig.Emit (OpCodes.Ldnull);
 785                         else
 786                                 delegate_instance_expression.Emit (ec);
 787
 788                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 789                                 ec.ig.Emit (OpCodes.Dup);
 790                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 791                         } else
 792                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 793                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 794                 }
 795
 796                 protected bool ResolveConstructorMethod (EmitContext ec)
 797                 {
 798                         Expression ml = Expression.MemberLookup (
 799                                 ec, type, ".ctor", loc);
 800
 801                         if (!(ml is MethodGroupExpr)) {
 802                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 803                                 return false;
 804                         }
 805
 806                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 807                         return true;
 808                 }
 809
 810                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 811                 {
 812                         foreach (MethodInfo mi in mg.Methods){
 813                                 delegate_method  = Delegate.VerifyMethod (ec, type, mi, loc);
 814
 815                                 if (delegate_method != null)
 816                                         break;
 817                         }
 818
 819                         if (delegate_method == null) {
 820                                 Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 821                                 return null;
 822                         }
 823
 824                         //
 825                         // Check safe/unsafe of the delegate
 826                         //
 827                         if (!ec.InUnsafe){
 828                                 ParameterData param = TypeManager.GetParameterData (delegate_method);
 829                                 int count = param.Count;
 830
 831                                 for (int i = 0; i < count; i++){
 832                                         if (param.ParameterType (i).IsPointer){
 833                                                 Expression.UnsafeError (loc);
 834                                                 return null;
 835                                         }
 836                                 }
 837                         }
 838
 839                         //TODO: implement caching when performance will be low
 840                         IMethodData md = TypeManager.GetMethod (delegate_method);
 841                         if (md == null) {
 842                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 843                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 844                                 }
 845                         } else {
 846                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 847                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 848                                 }
 849                         }
 850
 851                         if (mg.InstanceExpression != null)
 852                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 853                         else if (ec.IsStatic) {
 854                                 if (!delegate_method.IsStatic) {
 855                                         Report.Error (120, loc,
 856                                                       "An object reference is required for the non-static method " +
 857                                                       delegate_method.Name);
 858                                         return null;
 859                                 }
 860                                 delegate_instance_expression = null;
 861                         } else
 862                                 delegate_instance_expression = ec.GetThis (loc);
 863
 864                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 865                                 delegate_instance_expression = new BoxedCast (delegate_instance_expression);
 866
 867                         method_group = mg;
 868                         eclass = ExprClass.Value;
 869                         return this;
 870                 }
 871         }
 872
 873         //
 874         // Created from the conversion code
 875         //
 876         public class ImplicitDelegateCreation : DelegateCreation {
 877
 878                 ImplicitDelegateCreation (Type t, Location l)
 879                 {
 880                         type = t;
 881                         loc = l;
 882                 }
 883
 884                 public override Expression DoResolve (EmitContext ec)
 885                 {
 886                         return this;
 887                 }
 888
 889                 static public Expression Create (EmitContext ec, MethodGroupExpr mge, Type target_type, Location loc)
 890                 {
 891                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 892                         if (d.ResolveConstructorMethod (ec))
 893                                 return d.ResolveMethodGroupExpr (ec, mge);
 894                         else
 895                                 return null;
 896                 }
 897         }
 898
 899         //
 900         // A delegate-creation-expression, invoked from the `New' class
 901         //
 902         public class NewDelegate : DelegateCreation {
 903                 public ArrayList Arguments;
 904
 905                 //
 906                 // This constructor is invoked from the `New' expression
 907                 //
 908                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 909                 {
 910                         this.type = type;
 911                         this.Arguments = Arguments;
 912                         this.loc  = loc;
 913                 }
 914
 915                 public override Expression DoResolve (EmitContext ec)
 916                 {
 917                         if (Arguments == null || Arguments.Count != 1) {
 918                                 Report.Error (149, loc,
 919                                               "Method name expected");
 920                                 return null;
 921                         }
 922
 923                         if (!ResolveConstructorMethod (ec))
 924                                 return null;
 925
 926                         Argument a = (Argument) Arguments [0];
 927
 928                         if (!a.ResolveMethodGroup (ec, loc))
 929                                 return null;
 930
 931                         Expression e = a.Expr;
 932
 933                         if (e is AnonymousMethod && RootContext.Version != LanguageVersion.ISO_1)
 934                                 return ((AnonymousMethod) e).Compatible (ec, type, false);
 935
 936                         MethodGroupExpr mg = e as MethodGroupExpr;
 937                         if (mg != null)
 938                                 return ResolveMethodGroupExpr (ec, mg);
 939
 940                         Type e_type = e.Type;
 941
 942                         if (!TypeManager.IsDelegateType (e_type)) {
 943                                 Report.Error (149, loc, "Method name expected");
 944                                 return null;
 945                         }
 946
 947                         method_group = Expression.MemberLookup (
 948                                 ec, type, "Invoke", MemberTypes.Method,
 949                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 950
 951                         if (method_group == null) {
 952                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 953                                 return null;
 954                         }
 955
 956                         // This is what MS' compiler reports. We could always choose
 957                         // to be more verbose and actually give delegate-level specifics
 958                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 959                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 960                                               "to type '" + type + "'");
 961                                 return null;
 962                         }
 963
 964                         delegate_instance_expression = e;
 965                         delegate_method = method_group.Methods [0];
 966
 967                         eclass = ExprClass.Value;
 968                         return this;
 969                 }
 970         }
 971
 972         public class DelegateInvocation : ExpressionStatement {
 973
 974                 public Expression InstanceExpr;
 975                 public ArrayList  Arguments;
 976
 977                 MethodBase method;
 978
 979                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 980                 {
 981                         this.InstanceExpr = instance_expr;
 982                         this.Arguments = args;
 983                         this.loc = loc;
 984                 }
 985
 986                 public override Expression DoResolve (EmitContext ec)
 987                 {
 988                         if (InstanceExpr is EventExpr) {
 989
 990                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 991
 992                                 Expression ml = MemberLookup (
 993                                         ec, ec.ContainerType, ei.Name,
 994                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 995
 996                                 if (ml == null) {
 997                                         //
 998                                         // If this is the case, then the Event does not belong
 999                                         // to this Type and so, according to the spec
1000                                         // cannot be accessed directly
1001                                         //
1002                                         // Note that target will not appear as an EventExpr
1003                                         // in the case it is being referenced within the same type container;
1004                                         // it will appear as a FieldExpr in that case.
1005                                         //
1006
1007                                         Assign.error70 (ei, loc);
1008                                         return null;
1009                                 }
1010                         }
1011
1012
1013                         Type del_type = InstanceExpr.Type;
1014                         if (del_type == null)
1015                                 return null;
1016
1017                         if (Arguments != null){
1018                                 foreach (Argument a in Arguments){
1019                                         if (!a.Resolve (ec, loc))
1020                                                 return null;
1021                                 }
1022                         }
1023
1024                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
1025                                 return null;
1026
1027                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
1028                         if (!(lookup is MethodGroupExpr)) {
1029                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
1030                                 return null;
1031                         }
1032
1033                         method = ((MethodGroupExpr) lookup).Methods [0];
1034                         type = ((MethodInfo) method).ReturnType;
1035                         eclass = ExprClass.Value;
1036
1037                         return this;
1038                 }
1039
1040                 public override void Emit (EmitContext ec)
1041                 {
1042                         //
1043                         // Invocation on delegates call the virtual Invoke member
1044                         // so we are always `instance' calls
1045                         //
1046                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
1047                 }
1048
1049                 public override void EmitStatement (EmitContext ec)
1050                 {
1051                         Emit (ec);
1052                         //
1053                         // Pop the return value if there is one
1054                         //
1055                         if (method is MethodInfo){
1056                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
1057                                         ec.ig.Emit (OpCodes.Pop);
1058                         }
1059                 }
1060
1061         }
1062 }