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