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                 Expression instance_expr;
  38                 MethodBase delegate_method;
  39
  40                 const int AllowedModifiers =
  41                         Modifiers.NEW |
  42                         Modifiers.PUBLIC |
  43                         Modifiers.PROTECTED |
  44                         Modifiers.INTERNAL |
  45                         Modifiers.UNSAFE |
  46                         Modifiers.PRIVATE;
  47
  48                 public Delegate (NamespaceEntry ns, TypeContainer parent, Expression type,
  49                                  int mod_flags, string name, Parameters param_list,
  50                                  Attributes attrs, Location l)
  51                         : base (ns, parent, name, attrs, l)
  52
  53                 {
  54                         this.ReturnType = type;
  55                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  56                                                            IsTopLevel ? Modifiers.INTERNAL :
  57                                                            Modifiers.PRIVATE, l);
  58                         Parameters      = param_list;\r          }
  59
  60                 public override TypeBuilder DefineType ()
  61                 {
  62                         if (TypeBuilder != null)
  63                                 return TypeBuilder;
  64
  65                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel) |
  66                                 TypeAttributes.Class | TypeAttributes.Sealed;
  67
  68                         if (IsTopLevel) {
  69                                 if (TypeManager.NamespaceClash (Name, Location))
  70                                         return null;
  71
  72                                 ModuleBuilder builder = CodeGen.Module.Builder;
  73
  74                                 TypeBuilder = builder.DefineType (
  75                                         Name, attr, TypeManager.multicast_delegate_type);
  76                         } else {
  77                                 TypeBuilder builder = Parent.TypeBuilder;
  78
  79                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
  80                                 TypeBuilder = builder.DefineNestedType (
  81                                         name, attr, TypeManager.multicast_delegate_type);
  82                         }
  83
  84                         TypeManager.AddDelegateType (Name, TypeBuilder, this);
  85
  86                         return TypeBuilder;
  87                 }
  88
  89                 public override bool DefineMembers (TypeContainer container)
  90                 {
  91                         return true;
  92                 }
  93
  94                 public override bool Define (TypeContainer container)
  95                 {
  96                         MethodAttributes mattr;
  97                         int i;
  98                         ParameterBuilder pb;
  99                         Attributes cattr;
 100                         EmitContext ec = new EmitContext (this, this, Location, null,
 101                                                           null, ModFlags, false);
 102
 103                         // FIXME: POSSIBLY make this static, as it is always constant
 104                         //
 105                         Type [] const_arg_types = new Type [2];
 106                         const_arg_types [0] = TypeManager.object_type;
 107                         const_arg_types [1] = TypeManager.intptr_type;
 108
 109                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 110                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 111
 112                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 113                                                                             CallingConventions.Standard,
 114                                                                             const_arg_types);
 115
 116                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 117                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 118                         //
 119                         // HACK because System.Reflection.Emit is lame
 120                         //
 121                         //
 122                         // FIXME: POSSIBLY make these static, as they are always the same
 123                         Parameter [] fixed_pars = new Parameter [2];
 124                         fixed_pars [0] = new Parameter (null, null, Parameter.Modifier.NONE, null);
 125                         fixed_pars [1] = new Parameter (null, null, Parameter.Modifier.NONE, null);
 126                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);
 127
 128                         TypeManager.RegisterMethod (
 129                                 ConstructorBuilder,
 130                                 new InternalParameters (const_arg_types, const_parameters),
 131                                 const_arg_types);
 132
 133
 134                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 135
 136                         //
 137                         // Here the various methods like Invoke, BeginInvoke etc are defined
 138                         //
 139                         // First, call the `out of band' special method for
 140                         // defining recursively any types we need:
 141
 142                         if (!Parameters.ComputeAndDefineParameterTypes (this))
 143                                 return false;
 144
 145                         param_types = Parameters.GetParameterInfo (this);
 146                         if (param_types == null)
 147                                 return false;
 148
 149                         //
 150                         // Invoke method
 151                         //
 152
 153                         // Check accessibility
 154                         foreach (Type partype in param_types){
 155                                 if (!container.AsAccessible (partype, ModFlags)) {
 156                                         Report.Error (59, Location,
 157                                                       "Inconsistent accessibility: parameter type `" +
 158                                                       TypeManager.CSharpName (partype) + "` is less " +
 159                                                       "accessible than delegate `" + Name + "'");
 160                                         return false;
 161                                 }
 162                                 if (partype.IsPointer && !UnsafeOK (container))
 163                                         return false;
 164                         }
 165
 166                         ReturnType = ResolveTypeExpr (ReturnType, false, Location);
 167                         if (ReturnType == null)
 168                             return false;
 169
 170                         ret_type = ReturnType.Type;
 171                         if (ret_type == null)
 172                                 return false;
 173
 174                         if (!container.AsAccessible (ret_type, ModFlags)) {
 175                                 Report.Error (58, Location,
 176                                               "Inconsistent accessibility: return type `" +
 177                                               TypeManager.CSharpName (ret_type) + "` is less " +
 178                                               "accessible than delegate `" + Name + "'");
 179                                 return false;
 180                         }
 181
 182                         if (ret_type.IsPointer && !UnsafeOK (container))
 183                                 return false;
 184
 185                         //
 186                         // We don't have to check any others because they are all
 187                         // guaranteed to be accessible - they are standard types.
 188                         //
 189
 190                         CallingConventions cc = Parameters.GetCallingConvention ();
 191
 192                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 193
 194                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 195                                                                   mattr,
 196                                                                   cc,
 197                                                                   ret_type,
 198                                                                   param_types);
 199
 200                         //
 201                         // Define parameters, and count out/ref parameters
 202                         //
 203                         int out_params = 0;
 204                         i = 0;
 205                         if (Parameters.FixedParameters != null){
 206                                 int top = Parameters.FixedParameters.Length;
 207                                 Parameter p;
 208
 209                                 for (; i < top; i++) {
 210                                         p = Parameters.FixedParameters [i];
 211                                         pb = InvokeBuilder.DefineParameter (i+1, p.Attributes, p.Name);
 212                                         cattr = p.OptAttributes;
 213                                         if (cattr != null)
 214                                                 Attribute.ApplyAttributes (ec, pb, pb, cattr);
 215
 216                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 217                                                 out_params++;
 218                                 }
 219                         }
 220                         if (Parameters.ArrayParameter != null){
 221                                 Parameter p = Parameters.ArrayParameter;
 222
 223                                 pb = InvokeBuilder.DefineParameter (
 224                                         i+1, p.Attributes, p.Name);
 225                                 cattr = p.OptAttributes;
 226                                 if (cattr != null)
 227                                         Attribute.ApplyAttributes (ec, pb, pb, cattr);
 228                         }
 229
 230                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 231
 232                         TypeManager.RegisterMethod (InvokeBuilder,
 233                                                     new InternalParameters (container, Parameters),
 234                                                     param_types);
 235
 236                         //
 237                         // BeginInvoke
 238                         //
 239                         int params_num = param_types.Length;
 240                         Type [] async_param_types = new Type [params_num + 2];
 241
 242                         param_types.CopyTo (async_param_types, 0);
 243
 244                         async_param_types [params_num] = TypeManager.asynccallback_type;
 245                         async_param_types [params_num + 1] = TypeManager.object_type;
 246
 247                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 248                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 249
 250                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 251                                                                        mattr,
 252                                                                        cc,
 253                                                                        TypeManager.iasyncresult_type,
 254                                                                        async_param_types);
 255
 256                         i = 0;
 257                         if (Parameters.FixedParameters != null){
 258                                 int top = Parameters.FixedParameters.Length;
 259                                 Parameter p;
 260
 261                                 for (i = 0 ; i < top; i++) {
 262                                         p = Parameters.FixedParameters [i];
 263
 264                                         pb = BeginInvokeBuilder.DefineParameter (i+1, p.Attributes, p.Name);
 265                                         cattr = p.OptAttributes;
 266                                         if (cattr != null)
 267                                                 Attribute.ApplyAttributes (ec, pb, pb, cattr);
 268                                 }
 269                         }
 270                         if (Parameters.ArrayParameter != null){
 271                                 Parameter p = Parameters.ArrayParameter;
 272
 273                                 pb = BeginInvokeBuilder.DefineParameter (i+1, p.Attributes, p.Name);
 274                                 cattr = p.OptAttributes;
 275                                 if (cattr != null)
 276                                         Attribute.ApplyAttributes (ec, pb, pb, cattr);
 277                                 i++;
 278                         }
 279
 280                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 281                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 282
 283                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 284
 285                         Parameter [] async_params = new Parameter [params_num + 2];
 286                         int n = 0;
 287                         if (Parameters.FixedParameters != null){
 288                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 289                                 n = Parameters.FixedParameters.Length;
 290                         }
 291                         if (Parameters.ArrayParameter != null)
 292                                 async_params [n] = Parameters.ArrayParameter;
 293
 294                         async_params [params_num] = new Parameter (
 295                                 TypeManager.system_asynccallback_expr, "callback",
 296                                                                    Parameter.Modifier.NONE, null);
 297                         async_params [params_num + 1] = new Parameter (
 298                                 TypeManager.system_object_expr, "object",
 299                                                                    Parameter.Modifier.NONE, null);
 300
 301                         Parameters async_parameters = new Parameters (async_params, null, Location);
 302                         async_parameters.ComputeAndDefineParameterTypes (this);
 303
 304                         async_parameters.ComputeAndDefineParameterTypes (this);
 305                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 306                                                     new InternalParameters (container, async_parameters),
 307                                                     async_param_types);
 308
 309                         //
 310                         // EndInvoke is a bit more interesting, all the parameters labeled as
 311                         // out or ref have to be duplicated here.
 312                         //
 313
 314                         Type [] end_param_types = new Type [out_params + 1];
 315                         Parameter [] end_params = new Parameter [out_params + 1];
 316                         int param = 0;
 317                         if (out_params > 0){
 318                                 int top = Parameters.FixedParameters.Length;
 319                                 for (i = 0; i < top; i++){
 320                                         Parameter p = Parameters.FixedParameters [i];
 321                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 322                                                 continue;
 323
 324                                         end_param_types [param] = param_types [i];
 325                                         end_params [param] = p;
 326                                         param++;
 327                                 }
 328                         }
 329                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 330                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 331
 332                         //
 333                         // Create method, define parameters, register parameters with type system
 334                         //
 335                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 336                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 337
 338                         //
 339                         // EndInvoke: Label the parameters
 340                         //
 341                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 342                         for (i = 0; i < end_params.Length-1; i++){
 343                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 344                         }
 345
 346                         Parameters end_parameters = new Parameters (end_params, null, Location);
 347                         end_parameters.ComputeAndDefineParameterTypes (this);
 348
 349                         TypeManager.RegisterMethod (
 350                                 EndInvokeBuilder,
 351                                 new InternalParameters (container, end_parameters),
 352                                 end_param_types);
 353
 354                         Attribute.ApplyAttributes (ec, TypeBuilder, this, OptAttributes);
 355                         return true;
 356                 }
 357
 358                 /// <summary>
 359                 ///  Verifies whether the method in question is compatible with the delegate
 360                 ///  Returns the method itself if okay and null if not.
 361                 /// </summary>
 362                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 363                                                        Location loc)
 364                 {
 365                         ParameterData pd = Invocation.GetParameterData (mb);
 366
 367                         int pd_count = pd.Count;
 368
 369                         Expression ml = Expression.MemberLookup (
 370                                 ec, delegate_type, "Invoke", loc);
 371
 372                         if (!(ml is MethodGroupExpr)) {
 373                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 374                                 return null;
 375                         }
 376
 377                         MethodBase invoke_mb = ((MethodGroupExpr) ml).Methods [0];
 378
 379                         ParameterData invoke_pd = Invocation.GetParameterData (invoke_mb);
 380
 381                         if (invoke_pd.Count != pd_count)
 382                                 return null;
 383
 384                         for (int i = pd_count; i > 0; ) {
 385                                 i--;
 386
 387                                 if (invoke_pd.ParameterType (i) == pd.ParameterType (i) &&
 388                                     invoke_pd.ParameterModifier (i) == pd.ParameterModifier (i))
 389                                         continue;
 390                                 else {
 391                                         return null;
 392                                 }
 393                         }
 394
 395                         if (((MethodInfo) invoke_mb).ReturnType == ((MethodInfo) mb).ReturnType)
 396                                 return mb;
 397                         else
 398                                 return null;
 399                 }
 400
 401                 // <summary>
 402                 //  Verifies whether the invocation arguments are compatible with the
 403                 //  delegate's target method
 404                 // </summary>
 405                 public static bool VerifyApplicability (EmitContext ec,
 406                                                         Type delegate_type,
 407                                                         ArrayList args,
 408                                                         Location loc)
 409                 {
 410                         int arg_count;
 411
 412                         if (args == null)
 413                                 arg_count = 0;
 414                         else
 415                                 arg_count = args.Count;
 416
 417                         Expression ml = Expression.MemberLookup (
 418                                 ec, delegate_type, "Invoke", loc);
 419
 420                         if (!(ml is MethodGroupExpr)) {
 421                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 422                                 return false;
 423                         }
 424
 425                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 426                         ParameterData pd = Invocation.GetParameterData (mb);
 427
 428                         int pd_count = pd.Count;
 429
 430                         bool not_params_method = (pd_count == 0) ||
 431                                 (pd.ParameterModifier (pd_count - 1) != Parameter.Modifier.PARAMS);
 432
 433                         if (not_params_method && pd_count != arg_count) {
 434                                 Report.Error (1593, loc,
 435                                               "Delegate '" + delegate_type.ToString ()
 436                                               + "' does not take '" + arg_count + "' arguments");
 437                                 return false;
 438                         }
 439
 440                         return Invocation.VerifyArgumentsCompat (ec, args, arg_count, mb, !not_params_method,
 441                                                                  delegate_type, loc);
 442                 }
 443
 444                 /// <summary>
 445                 ///  Verifies whether the delegate in question is compatible with this one in
 446                 ///  order to determine if instantiation from the same is possible.
 447                 /// </summary>
 448                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 449                 {
 450                         Expression ml = Expression.MemberLookup (
 451                                 ec, delegate_type, "Invoke", loc);
 452
 453                         if (!(ml is MethodGroupExpr)) {
 454                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 455                                 return false;
 456                         }
 457
 458                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 459                         ParameterData pd = Invocation.GetParameterData (mb);
 460
 461                         Expression probe_ml = Expression.MemberLookup (
 462                                 ec, delegate_type, "Invoke", loc);
 463
 464                         if (!(probe_ml is MethodGroupExpr)) {
 465                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 466                                 return false;
 467                         }
 468
 469                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 470                         ParameterData probe_pd = Invocation.GetParameterData (probe_mb);
 471
 472                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 473                                 return false;
 474
 475                         if (pd.Count != probe_pd.Count)
 476                                 return false;
 477
 478                         for (int i = pd.Count; i > 0; ) {
 479                                 i--;
 480
 481                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 482                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 483                                         return false;
 484                         }
 485
 486                         return true;
 487                 }
 488
 489                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 490                 {
 491                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 492
 493                         sb.Append (" " + del_type.ToString ());
 494                         sb.Append (" (");
 495
 496                         int length = pd.Count;
 497
 498                         for (int i = length; i > 0; ) {
 499                                 i--;
 500
 501                                 sb.Append (pd.ParameterDesc (length - i - 1));
 502                                 if (i != 0)
 503                                         sb.Append (", ");
 504                         }
 505
 506                         sb.Append (")");
 507                         return sb.ToString ();
 508
 509                 }
 510
 511                 // Hack around System.Reflection as found everywhere else
 512                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 513                                                         MemberFilter filter, object criteria)
 514                 {
 515                         ArrayList members = new ArrayList ();
 516
 517                         if ((mt & MemberTypes.Method) != 0) {
 518                                 if (ConstructorBuilder != null)
 519                                 if (filter (ConstructorBuilder, criteria))
 520                                         members.Add (ConstructorBuilder);
 521
 522                                 if (InvokeBuilder != null)
 523                                 if (filter (InvokeBuilder, criteria))
 524                                         members.Add (InvokeBuilder);
 525
 526                                 if (BeginInvokeBuilder != null)
 527                                 if (filter (BeginInvokeBuilder, criteria))
 528                                         members.Add (BeginInvokeBuilder);
 529
 530                                 if (EndInvokeBuilder != null)
 531                                 if (filter (EndInvokeBuilder, criteria))
 532                                         members.Add (EndInvokeBuilder);
 533                         }
 534
 535                         return new MemberList (members);
 536                 }
 537
 538                 public override MemberCache MemberCache {
 539                         get {
 540                                 return null;
 541                         }
 542                 }
 543
 544                 public Expression InstanceExpression {
 545                         get {
 546                                 return instance_expr;
 547                         }
 548                         set {
 549                                 instance_expr = value;
 550                         }
 551                 }
 552
 553                 public MethodBase TargetMethod {
 554                         get {
 555                                 return delegate_method;
 556                         }
 557                         set {
 558                                 delegate_method = value;
 559                         }
 560                 }
 561
 562                 public Type TargetReturnType {
 563                         get {
 564                                 return ret_type;
 565                         }
 566                 }
 567
 568                 public Type [] ParameterTypes {
 569                         get {
 570                                 return param_types;
 571                         }
 572                 }
 573
 574         }
 575
 576         //
 577         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 578         //
 579         public abstract class DelegateCreation : Expression {
 580                 protected MethodBase constructor_method;
 581                 protected MethodBase delegate_method;
 582                 protected Expression delegate_instance_expr;
 583
 584                 public DelegateCreation () {}
 585
 586                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 587                 {
 588                         string method_desc;
 589
 590                         if (mg.Methods.Length > 1)
 591                                 method_desc = mg.Methods [0].Name;
 592                         else
 593                                 method_desc = Invocation.FullMethodDesc (mg.Methods [0]);
 594
 595                         Expression invoke_method = Expression.MemberLookup (
 596                                 ec, type, "Invoke", MemberTypes.Method,
 597                                 Expression.AllBindingFlags, loc);
 598                         MethodBase method = ((MethodGroupExpr) invoke_method).Methods [0];
 599                         ParameterData param = Invocation.GetParameterData (method);
 600                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 601
 602                         Report.Error (123, loc, "Method '" + method_desc + "' does not " +
 603                                       "match delegate '" + delegate_desc + "'");
 604                 }
 605
 606                 public override void Emit (EmitContext ec)
 607                 {
 608                         if (delegate_instance_expr == null ||
 609                             delegate_method.IsStatic)
 610                                 ec.ig.Emit (OpCodes.Ldnull);
 611                         else
 612                                 delegate_instance_expr.Emit (ec);
 613
 614                         if (delegate_method.IsVirtual) {
 615                                 ec.ig.Emit (OpCodes.Dup);
 616                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 617                         } else
 618                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 619                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 620                 }
 621
 622                 protected bool ResolveConstructorMethod (EmitContext ec)
 623                 {
 624                         Expression ml = Expression.MemberLookup (
 625                                 ec, type, ".ctor", loc);
 626
 627                         if (!(ml is MethodGroupExpr)) {
 628                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 629                                 return false;
 630                         }
 631
 632                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 633                         return true;
 634                 }
 635
 636                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 637                 {
 638                         foreach (MethodInfo mi in mg.Methods){
 639                                 delegate_method  = Delegate.VerifyMethod (ec, type, mi, loc);
 640
 641                                 if (delegate_method != null)
 642                                         break;
 643                         }
 644
 645                         if (delegate_method == null) {
 646                                 Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 647                                 return null;
 648                         }
 649
 650                         //
 651                         // Check safe/unsafe of the delegate
 652                         //
 653                         if (!ec.InUnsafe){
 654                                 ParameterData param = Invocation.GetParameterData (delegate_method);
 655                                 int count = param.Count;
 656
 657                                 for (int i = 0; i < count; i++){
 658                                         if (param.ParameterType (i).IsPointer){
 659                                                 Expression.UnsafeError (loc);
 660                                                 return null;
 661                                         }
 662                                 }
 663                         }
 664
 665                         if (mg.InstanceExpression != null)
 666                                 delegate_instance_expr = mg.InstanceExpression.Resolve (ec);
 667                         else {
 668                                 if (ec.IsStatic){
 669                                         if (!delegate_method.IsStatic){
 670                                                 Report.Error (120, loc,
 671                                                               "An object reference is required for the non-static method " +
 672                                                               delegate_method.Name);
 673                                                 return null;
 674                                         }
 675                                         delegate_instance_expr = null;
 676                                 } else
 677                                         delegate_instance_expr = ec.GetThis (loc);
 678                         }
 679
 680                         if (delegate_instance_expr != null)
 681                                 if (delegate_instance_expr.Type.IsValueType)
 682                                         delegate_instance_expr = new BoxedCast (delegate_instance_expr);
 683
 684                         eclass = ExprClass.Value;
 685                         return this;
 686                 }
 687         }
 688
 689         //
 690         // Created from the conversion code
 691         //
 692         public class ImplicitDelegateCreation : DelegateCreation {
 693
 694                 ImplicitDelegateCreation (Type t, Location l)
 695                 {
 696                         type = t;
 697                         loc = l;
 698                 }
 699
 700                 public override Expression DoResolve (EmitContext ec)
 701                 {
 702                         return this;
 703                 }
 704
 705                 static public Expression Create (EmitContext ec, MethodGroupExpr mge, Type target_type, Location loc)
 706                 {
 707                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 708                         if (d.ResolveConstructorMethod (ec))
 709                                 return d.ResolveMethodGroupExpr (ec, mge);
 710                         else
 711                                 return null;
 712                 }
 713         }
 714
 715         //
 716         // A delegate-creation-expression, invoked from the `New' class
 717         //
 718         public class NewDelegate : DelegateCreation {
 719                 public ArrayList Arguments;
 720
 721                 //
 722                 // This constructor is invoked from the `New' expression
 723                 //
 724                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 725                 {
 726                         this.type = type;
 727                         this.Arguments = Arguments;
 728                         this.loc  = loc;
 729                 }
 730
 731                 public override Expression DoResolve (EmitContext ec)
 732                 {
 733                         if (Arguments == null || Arguments.Count != 1) {
 734                                 Report.Error (149, loc,
 735                                               "Method name expected");
 736                                 return null;
 737                         }
 738
 739                         if (!ResolveConstructorMethod (ec))
 740                                 return null;
 741
 742                         Argument a = (Argument) Arguments [0];
 743
 744                         Expression invoke_method = Expression.MemberLookup (
 745                                 ec, type, "Invoke", MemberTypes.Method,
 746                                 Expression.AllBindingFlags, loc);
 747
 748                         if (invoke_method == null) {
 749                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 750                                 return null;
 751                         }
 752
 753                         if (!a.ResolveMethodGroup (ec, loc))
 754                                 return null;
 755
 756                         Expression e = a.Expr;
 757
 758                         MethodGroupExpr mg = e as MethodGroupExpr;
 759                         if (mg != null)
 760                                 return ResolveMethodGroupExpr (ec, mg);
 761
 762                         Type e_type = e.Type;
 763
 764                         if (!TypeManager.IsDelegateType (e_type)) {
 765                                 e.Error_UnexpectedKind ("method");
 766                                 return null;
 767                         }
 768
 769                         // This is what MS' compiler reports. We could always choose
 770                         // to be more verbose and actually give delegate-level specifics
 771
 772                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 773                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 774                                               "to type '" + type + "'");
 775                                 return null;
 776                         }
 777
 778                         delegate_instance_expr = e;
 779                         delegate_method = ((MethodGroupExpr) invoke_method).Methods [0];
 780
 781                         eclass = ExprClass.Value;
 782                         return this;
 783                 }
 784
 785                 public override void Emit (EmitContext ec)
 786                 {
 787                         if (delegate_instance_expr == null || delegate_method.IsStatic)
 788                                 ec.ig.Emit (OpCodes.Ldnull);
 789                         else
 790                                 delegate_instance_expr.Emit (ec);
 791
 792                         if (delegate_method.IsVirtual) {
 793                                 ec.ig.Emit (OpCodes.Dup);
 794                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 795                         } else
 796                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 797                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 798                 }
 799         }
 800
 801         public class DelegateInvocation : ExpressionStatement {
 802
 803                 public Expression InstanceExpr;
 804                 public ArrayList  Arguments;
 805
 806                 MethodBase method;
 807
 808                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 809                 {
 810                         this.InstanceExpr = instance_expr;
 811                         this.Arguments = args;
 812                         this.loc = loc;
 813                 }
 814
 815                 public override Expression DoResolve (EmitContext ec)
 816                 {
 817                         if (InstanceExpr is EventExpr) {
 818
 819                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 820
 821                                 Expression ml = MemberLookup (
 822                                         ec, ec.ContainerType, ei.Name,
 823                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 824
 825                                 if (ml == null) {
 826                                         //
 827                                         // If this is the case, then the Event does not belong
 828                                         // to this Type and so, according to the spec
 829                                         // cannot be accessed directly
 830                                         //
 831                                         // Note that target will not appear as an EventExpr
 832                                         // in the case it is being referenced within the same type container;
 833                                         // it will appear as a FieldExpr in that case.
 834                                         //
 835
 836                                         Assign.error70 (ei, loc);
 837                                         return null;
 838                                 }
 839                         }
 840
 841
 842                         Type del_type = InstanceExpr.Type;
 843                         if (del_type == null)
 844                                 return null;
 845
 846                         if (Arguments != null){
 847                                 foreach (Argument a in Arguments){
 848                                         if (!a.Resolve (ec, loc))
 849                                                 return null;
 850                                 }
 851                         }
 852
 853                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 854                                 return null;
 855
 856                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
 857                         if (!(lookup is MethodGroupExpr)) {
 858                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 859                                 return null;
 860                         }
 861
 862                         method = ((MethodGroupExpr) lookup).Methods [0];
 863                         type = ((MethodInfo) method).ReturnType;
 864                         eclass = ExprClass.Value;
 865
 866                         return this;
 867                 }
 868
 869                 public override void Emit (EmitContext ec)
 870                 {
 871                         //
 872                         // Invocation on delegates call the virtual Invoke member
 873                         // so we are always `instance' calls
 874                         //
 875                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
 876                 }
 877
 878                 public override void EmitStatement (EmitContext ec)
 879                 {
 880                         Emit (ec);
 881                         //
 882                         // Pop the return value if there is one
 883                         //
 884                         if (method is MethodInfo){
 885                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
 886                                         ec.ig.Emit (OpCodes.Pop);
 887                         }
 888                 }
 889
 890         }
 891 }