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