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