mcs/gmcs/delegate.cs

   1 //
   2 // delegate.cs: Delegate Handler
   3 //
   4 // Authors:
   5 //     Ravi Pratap (ravi@ximian.com)
   6 //     Miguel de Icaza (miguel@ximian.com)
   7 //
   8 // Licensed under the terms of the GNU GPL
   9 //
  10 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  11 //
  12 //
  13
  14 using System;
  15 using System.Collections;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.Text;
  19
  20 namespace Mono.CSharp {
  21
  22         /// <summary>
  23         ///   Holds Delegates
  24         /// </summary>
  25         public class Delegate : DeclSpace {
  26                 public Expression ReturnType;
  27                 public Parameters      Parameters;
  28
  29                 public ConstructorBuilder ConstructorBuilder;
  30                 public MethodBuilder      InvokeBuilder;
  31                 public MethodBuilder      BeginInvokeBuilder;
  32                 public MethodBuilder      EndInvokeBuilder;
  33
  34                 Type [] param_types;
  35                 Type ret_type;
  36
  37                 static string[] attribute_targets = new string [] { "type", "return" };
  38
  39                 Expression instance_expr;
  40                 MethodBase delegate_method;
  41                 ReturnParameter return_attributes;
  42
  43                 const int AllowedModifiers =
  44                         Modifiers.NEW |
  45                         Modifiers.PUBLIC |
  46                         Modifiers.PROTECTED |
  47                         Modifiers.INTERNAL |
  48                         Modifiers.UNSAFE |
  49                         Modifiers.PRIVATE;
  50
  51                 public Delegate (NamespaceEntry ns, TypeContainer parent, Expression type,
  52                                  int mod_flags, MemberName name, Parameters param_list,
  53                                  Attributes attrs, Location l)
  54                         : base (ns, parent, name, attrs, l)
  55
  56                 {
  57                         this.ReturnType = type;
  58                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  59                                                            IsTopLevel ? Modifiers.INTERNAL :
  60                                                            Modifiers.PRIVATE, l);
  61                         Parameters      = param_list;
  62                 }
  63
  64                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  65                 {
  66                         if (a.Target == AttributeTargets.ReturnValue) {
  67                                 if (return_attributes == null)
  68                                         return_attributes = new ReturnParameter (InvokeBuilder, Location);
  69
  70                                 return_attributes.ApplyAttributeBuilder (a, cb);
  71                                 return;
  72                         }
  73
  74                         base.ApplyAttributeBuilder (a, cb);
  75                 }
  76
  77                 public override TypeBuilder DefineType ()
  78                 {
  79                         if (TypeBuilder != null)
  80                                 return TypeBuilder;
  81
  82                         if (IsGeneric) {
  83                                 foreach (TypeParameter type_param in TypeParameters)
  84                                         if (!type_param.Resolve (this))
  85                                                 return null;
  86                         }
  87
  88                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel) |
  89                                 TypeAttributes.Class | TypeAttributes.Sealed;
  90
  91                         if (IsTopLevel) {
  92                                 if (TypeManager.NamespaceClash (Name, Location))
  93                                         return null;
  94
  95                                 ModuleBuilder builder = CodeGen.Module.Builder;
  96
  97                                 TypeBuilder = builder.DefineType (
  98                                         Name, attr, TypeManager.multicast_delegate_type);
  99                         } else {
 100                                 TypeBuilder builder = Parent.TypeBuilder;
 101
 102                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
 103                                 TypeBuilder = builder.DefineNestedType (
 104                                         name, attr, TypeManager.multicast_delegate_type);
 105                         }
 106
 107                         TypeManager.AddDelegateType (Name, TypeBuilder, this);
 108
 109                         if (IsGeneric) {
 110                                 CurrentType = new ConstructedType (
 111                                         Name, TypeParameters, Location);
 112
 113                                 EmitContext ec = new EmitContext (
 114                                         this, this, Location, null, null, ModFlags, false);
 115
 116                                 string[] param_names = new string [TypeParameters.Length];
 117                                 for (int i = 0; i < TypeParameters.Length; i++)
 118                                         param_names [i] = TypeParameters [i].Name;
 119
 120                                 GenericTypeParameterBuilder[] gen_params;
 121
 122                                 gen_params = TypeBuilder.DefineGenericParameters (param_names);
 123
 124                                 for (int i = 0; i < gen_params.Length; i++)
 125                                         TypeParameters [i].Define (gen_params [i]);
 126
 127                                 foreach (TypeParameter type_param in TypeParameters) {
 128                                         if (!type_param.DefineType (ec))
 129                                                 return null;
 130                                 }
 131                         }
 132
 133                         return TypeBuilder;
 134                 }
 135
 136                 public override bool DefineMembers (TypeContainer container)
 137                 {
 138                         return true;
 139                 }
 140
 141                 public override bool Define ()
 142                 {
 143                         MethodAttributes mattr;
 144                         int i;
 145                         EmitContext ec = new EmitContext (this, this, Location, null,
 146                                                           null, ModFlags, false);
 147
 148                         if (IsGeneric) {
 149                                 foreach (TypeParameter type_param in TypeParameters)
 150                                         type_param.DefineType (ec);
 151                         }
 152
 153                         // FIXME: POSSIBLY make this static, as it is always constant
 154                         //
 155                         Type [] const_arg_types = new Type [2];
 156                         const_arg_types [0] = TypeManager.object_type;
 157                         const_arg_types [1] = TypeManager.intptr_type;
 158
 159                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 160                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 161
 162                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 163                                                                             CallingConventions.Standard,
 164                                                                             const_arg_types);
 165
 166                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 167                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 168                         //
 169                         // HACK because System.Reflection.Emit is lame
 170                         //
 171                         //
 172                         // FIXME: POSSIBLY make these static, as they are always the same
 173                         Parameter [] fixed_pars = new Parameter [2];
 174                         fixed_pars [0] = new Parameter (null, null, Parameter.Modifier.NONE, null);
 175                         fixed_pars [1] = new Parameter (null, null, Parameter.Modifier.NONE, null);
 176                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);
 177
 178                         TypeManager.RegisterMethod (
 179                                 ConstructorBuilder,
 180                                 new InternalParameters (const_arg_types, const_parameters),
 181                                 const_arg_types);
 182
 183
 184                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 185
 186                         //
 187                         // Here the various methods like Invoke, BeginInvoke etc are defined
 188                         //
 189                         // First, call the `out of band' special method for
 190                         // defining recursively any types we need:
 191
 192                         if (!Parameters.ComputeAndDefineParameterTypes (this))
 193                                 return false;
 194
 195                         param_types = Parameters.GetParameterInfo (this);
 196                         if (param_types == null)
 197                                 return false;
 198
 199                         //
 200                         // Invoke method
 201                         //
 202
 203                         // Check accessibility
 204                         foreach (Type partype in param_types){
 205                                 if (!Parent.AsAccessible (partype, ModFlags)) {
 206                                         Report.Error (59, Location,
 207                                                       "Inconsistent accessibility: parameter type `" +
 208                                                       TypeManager.CSharpName (partype) + "` is less " +
 209                                                       "accessible than delegate `" + Name + "'");
 210                                         return false;
 211                                 }
 212                                 if (partype.IsPointer && !UnsafeOK (Parent))
 213                                         return false;
 214                         }
 215
 216                         ReturnType = ResolveTypeExpr (ReturnType, false, Location);
 217                         if (ReturnType == null)
 218                             return false;
 219
 220                         ret_type = ReturnType.Type;
 221                         if (ret_type == null)
 222                                 return false;
 223
 224                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 225                                 Report.Error (58, Location,
 226                                               "Inconsistent accessibility: return type `" +
 227                                               TypeManager.CSharpName (ret_type) + "` is less " +
 228                                               "accessible than delegate `" + Name + "'");
 229                                 return false;
 230                         }
 231
 232                         if (ret_type.IsPointer && !UnsafeOK (Parent))
 233                                 return false;
 234
 235                         //
 236                         // We don't have to check any others because they are all
 237                         // guaranteed to be accessible - they are standard types.
 238                         //
 239
 240                         CallingConventions cc = Parameters.GetCallingConvention ();
 241
 242                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 243
 244                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 245                                                                   mattr,
 246                                                                   cc,
 247                                                                   ret_type,
 248                                                                   param_types);
 249
 250                         //
 251                         // Define parameters, and count out/ref parameters
 252                         //
 253                         int out_params = 0;
 254                         i = 0;
 255                         if (Parameters.FixedParameters != null){
 256                                 int top = Parameters.FixedParameters.Length;
 257                                 Parameter p;
 258
 259                                 for (; i < top; i++) {
 260                                         p = Parameters.FixedParameters [i];
 261                                         p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 262
 263                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 264                                                 out_params++;
 265                                 }
 266                         }
 267                         if (Parameters.ArrayParameter != null){
 268                                 Parameter p = Parameters.ArrayParameter;
 269                                 p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 270                         }
 271
 272                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 273
 274                         TypeManager.RegisterMethod (InvokeBuilder,
 275                                                     new InternalParameters (Parent, Parameters),
 276                                                     param_types);
 277
 278                         //
 279                         // BeginInvoke
 280                         //
 281                         int params_num = param_types.Length;
 282                         Type [] async_param_types = new Type [params_num + 2];
 283
 284                         param_types.CopyTo (async_param_types, 0);
 285
 286                         async_param_types [params_num] = TypeManager.asynccallback_type;
 287                         async_param_types [params_num + 1] = TypeManager.object_type;
 288
 289                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 290                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 291
 292                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 293                                                                        mattr,
 294                                                                        cc,
 295                                                                        TypeManager.iasyncresult_type,
 296                                                                        async_param_types);
 297
 298                         i = 0;
 299                         if (Parameters.FixedParameters != null){
 300                                 int top = Parameters.FixedParameters.Length;
 301                                 Parameter p;
 302
 303                                 for (i = 0 ; i < top; i++) {
 304                                         p = Parameters.FixedParameters [i];
 305
 306                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 307                                 }
 308                         }
 309                         if (Parameters.ArrayParameter != null){
 310                                 Parameter p = Parameters.ArrayParameter;
 311                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 312
 313                                 i++;
 314                         }
 315
 316                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 317                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 318
 319                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 320
 321                         Parameter [] async_params = new Parameter [params_num + 2];
 322                         int n = 0;
 323                         if (Parameters.FixedParameters != null){
 324                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 325                                 n = Parameters.FixedParameters.Length;
 326                         }
 327                         if (Parameters.ArrayParameter != null)
 328                                 async_params [n] = Parameters.ArrayParameter;
 329
 330                         async_params [params_num] = new Parameter (
 331                                 TypeManager.system_asynccallback_expr, "callback",
 332                                                                    Parameter.Modifier.NONE, null);
 333                         async_params [params_num + 1] = new Parameter (
 334                                 TypeManager.system_object_expr, "object",
 335                                                                    Parameter.Modifier.NONE, null);
 336
 337                         Parameters async_parameters = new Parameters (async_params, null, Location);
 338                         async_parameters.ComputeAndDefineParameterTypes (this);
 339
 340                         async_parameters.ComputeAndDefineParameterTypes (this);
 341                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 342                                                     new InternalParameters (Parent, async_parameters),
 343                                                     async_param_types);
 344
 345                         //
 346                         // EndInvoke is a bit more interesting, all the parameters labeled as
 347                         // out or ref have to be duplicated here.
 348                         //
 349
 350                         Type [] end_param_types = new Type [out_params + 1];
 351                         Parameter [] end_params = new Parameter [out_params + 1];
 352                         int param = 0;
 353                         if (out_params > 0){
 354                                 int top = Parameters.FixedParameters.Length;
 355                                 for (i = 0; i < top; i++){
 356                                         Parameter p = Parameters.FixedParameters [i];
 357                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 358                                                 continue;
 359
 360                                         end_param_types [param] = param_types [i];
 361                                         end_params [param] = p;
 362                                         param++;
 363                                 }
 364                         }
 365                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 366                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 367
 368                         //
 369                         // Create method, define parameters, register parameters with type system
 370                         //
 371                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 372                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 373
 374                         //
 375                         // EndInvoke: Label the parameters
 376                         //
 377                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 378                         for (i = 0; i < end_params.Length-1; i++){
 379                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 380                         }
 381
 382                         Parameters end_parameters = new Parameters (end_params, null, Location);
 383                         end_parameters.ComputeAndDefineParameterTypes (this);
 384
 385                         TypeManager.RegisterMethod (
 386                                 EndInvokeBuilder,
 387                                 new InternalParameters (Parent, end_parameters),
 388                                 end_param_types);
 389
 390                         return true;
 391                 }
 392
 393                 public override void Emit ()
 394                 {
 395                         if (OptAttributes != null) {
 396                                 EmitContext ec = new EmitContext (
 397                                         Parent, this, Location, null, null, ModFlags, false);
 398                                 Parameters.LabelParameters (ec, InvokeBuilder, Location);
 399                                 OptAttributes.Emit (ec, this);
 400                         }
 401
 402                         base.Emit ();
 403                 }
 404
 405                 public override string[] ValidAttributeTargets {
 406                         get {
 407                                 return attribute_targets;
 408                         }
 409                 }
 410
 411                 //TODO: duplicate
 412                 protected override bool VerifyClsCompliance (DeclSpace ds)
 413                 {
 414                         if (!base.VerifyClsCompliance (ds)) {
 415                                 return false;
 416                         }
 417
 418                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 419
 420                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 421                                 Report.Error (3002, Location, "Return type of '{0}' is not CLS-compliant", GetSignatureForError ());
 422                         }
 423                         return true;
 424                 }
 425
 426                 /// <summary>
 427                 ///  Verifies whether the method in question is compatible with the delegate
 428                 ///  Returns the method itself if okay and null if not.
 429                 /// </summary>
 430                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 431                                                        Location loc)
 432                 {
 433                         Expression ml = Expression.MemberLookup (
 434                                 ec, delegate_type, "Invoke", loc);
 435
 436                         if (!(ml is MethodGroupExpr)) {
 437                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 438                                 return null;
 439                         }
 440
 441                         MethodBase invoke_mb = ((MethodGroupExpr) ml).Methods [0];
 442
 443                         ParameterData invoke_pd = Invocation.GetParameterData (invoke_mb);
 444
 445                         if (!((MethodGroupExpr) ml).HasTypeArguments &&
 446                             !Invocation.InferTypeArguments (ec, invoke_pd, ref mb))
 447                                 return null;
 448
 449                         ParameterData pd = Invocation.GetParameterData (mb);
 450                         int pd_count = pd.Count;
 451
 452                         if (invoke_pd.Count != pd_count)
 453                                 return null;
 454
 455                         for (int i = pd_count; i > 0; ) {
 456                                 i--;
 457
 458                                 if (invoke_pd.ParameterType (i) == pd.ParameterType (i) &&
 459                                     invoke_pd.ParameterModifier (i) == pd.ParameterModifier (i))
 460                                         continue;
 461                                 else {
 462                                         return null;
 463                                 }
 464                         }
 465
 466                         if (((MethodInfo) invoke_mb).ReturnType == ((MethodInfo) mb).ReturnType)
 467                                 return mb;
 468                         else
 469                                 return null;
 470                 }
 471
 472                 // <summary>
 473                 //  Verifies whether the invocation arguments are compatible with the
 474                 //  delegate's target method
 475                 // </summary>
 476                 public static bool VerifyApplicability (EmitContext ec,
 477                                                         Type delegate_type,
 478                                                         ArrayList args,
 479                                                         Location loc)
 480                 {
 481                         int arg_count;
 482
 483                         if (args == null)
 484                                 arg_count = 0;
 485                         else
 486                                 arg_count = args.Count;
 487
 488                         Expression ml = Expression.MemberLookup (
 489                                 ec, delegate_type, "Invoke", loc);
 490
 491                         if (!(ml is MethodGroupExpr)) {
 492                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 493                                 return false;
 494                         }
 495
 496                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 497                         ParameterData pd = Invocation.GetParameterData (mb);
 498
 499                         int pd_count = pd.Count;
 500
 501                         bool params_method = (pd_count != 0) &&
 502                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 503
 504                         if (!params_method && pd_count != arg_count) {
 505                                 Report.Error (1593, loc,
 506                                               "Delegate '" + delegate_type.ToString ()
 507                                               + "' does not take '" + arg_count + "' arguments");
 508                                 return false;
 509                         }
 510
 511                         //
 512                         // Consider the case:
 513                         //   delegate void FOO(param object[] args);
 514                         //   FOO f = new FOO(...);
 515                         //   f(new object[] {1, 2, 3});
 516                         //
 517                         // This should be treated like f(1,2,3).  This is done by ignoring the
 518                         // 'param' modifier for that invocation.  If that fails, then the
 519                         // 'param' modifier is considered.
 520                         //
 521                         // One issue is that 'VerifyArgumentsCompat' modifies the elements of
 522                         // the 'args' array.  However, the modifications appear idempotent.
 523                         // Normal 'Invocation's also have the same behaviour, implicitly.
 524                         //
 525
 526                         bool ans = false;
 527                         if (arg_count == pd_count)
 528                                 ans = Invocation.VerifyArgumentsCompat (ec, args, arg_count, mb, false, delegate_type, loc);
 529                         if (!ans && params_method)
 530                                 ans = Invocation.VerifyArgumentsCompat (ec, args, arg_count, mb, true,  delegate_type, loc);
 531                         return ans;
 532                 }
 533
 534                 /// <summary>
 535                 ///  Verifies whether the delegate in question is compatible with this one in
 536                 ///  order to determine if instantiation from the same is possible.
 537                 /// </summary>
 538                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 539                 {
 540                         Expression ml = Expression.MemberLookup (
 541                                 ec, delegate_type, "Invoke", loc);
 542
 543                         if (!(ml is MethodGroupExpr)) {
 544                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 545                                 return false;
 546                         }
 547
 548                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 549                         ParameterData pd = Invocation.GetParameterData (mb);
 550
 551                         Expression probe_ml = Expression.MemberLookup (
 552                                 ec, delegate_type, "Invoke", loc);
 553
 554                         if (!(probe_ml is MethodGroupExpr)) {
 555                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 556                                 return false;
 557                         }
 558
 559                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 560                         ParameterData probe_pd = Invocation.GetParameterData (probe_mb);
 561
 562                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 563                                 return false;
 564
 565                         if (pd.Count != probe_pd.Count)
 566                                 return false;
 567
 568                         for (int i = pd.Count; i > 0; ) {
 569                                 i--;
 570
 571                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 572                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 573                                         return false;
 574                         }
 575
 576                         return true;
 577                 }
 578
 579                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 580                 {
 581                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 582
 583                         sb.Append (" " + del_type.ToString ());
 584                         sb.Append (" (");
 585
 586                         int length = pd.Count;
 587
 588                         for (int i = length; i > 0; ) {
 589                                 i--;
 590
 591                                 sb.Append (pd.ParameterDesc (length - i - 1));
 592                                 if (i != 0)
 593                                         sb.Append (", ");
 594                         }
 595
 596                         sb.Append (")");
 597                         return sb.ToString ();
 598
 599                 }
 600
 601                 // Hack around System.Reflection as found everywhere else
 602                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 603                                                         MemberFilter filter, object criteria)
 604                 {
 605                         ArrayList members = new ArrayList ();
 606
 607                         if ((mt & MemberTypes.Method) != 0) {
 608                                 if (ConstructorBuilder != null)
 609                                 if (filter (ConstructorBuilder, criteria))
 610                                         members.Add (ConstructorBuilder);
 611
 612                                 if (InvokeBuilder != null)
 613                                 if (filter (InvokeBuilder, criteria))
 614                                         members.Add (InvokeBuilder);
 615
 616                                 if (BeginInvokeBuilder != null)
 617                                 if (filter (BeginInvokeBuilder, criteria))
 618                                         members.Add (BeginInvokeBuilder);
 619
 620                                 if (EndInvokeBuilder != null)
 621                                 if (filter (EndInvokeBuilder, criteria))
 622                                         members.Add (EndInvokeBuilder);
 623                         }
 624
 625                         return new MemberList (members);
 626                 }
 627
 628                 public override MemberCache MemberCache {
 629                         get {
 630                                 return null;
 631                         }
 632                 }
 633
 634                 public Expression InstanceExpression {
 635                         get {
 636                                 return instance_expr;
 637                         }
 638                         set {
 639                                 instance_expr = value;
 640                         }
 641                 }
 642
 643                 public MethodBase TargetMethod {
 644                         get {
 645                                 return delegate_method;
 646                         }
 647                         set {
 648                                 delegate_method = value;
 649                         }
 650                 }
 651
 652                 public Type TargetReturnType {
 653                         get {
 654                                 return ret_type;
 655                         }
 656                 }
 657
 658                 public Type [] ParameterTypes {
 659                         get {
 660                                 return param_types;
 661                         }
 662                 }
 663
 664                 public override AttributeTargets AttributeTargets {
 665                         get {
 666                                 return AttributeTargets.Delegate;
 667                         }
 668                 }
 669
 670                 protected override void VerifyObsoleteAttribute()
 671                 {
 672                         CheckUsageOfObsoleteAttribute (ret_type);
 673
 674                         foreach (Type type in param_types) {
 675                                 CheckUsageOfObsoleteAttribute (type);
 676                         }
 677                 }
 678         }
 679
 680         //
 681         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 682         //
 683         public abstract class DelegateCreation : Expression {
 684                 protected MethodBase constructor_method;
 685                 protected MethodBase delegate_method;
 686                 protected MethodGroupExpr method_group;
 687
 688                 public DelegateCreation () {}
 689
 690                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 691                 {
 692                         string method_desc;
 693
 694                         MethodBase candidate = mg.Methods [0];
 695                         if (mg.Methods.Length > 1)
 696                                 method_desc = candidate.Name;
 697                         else
 698                                 method_desc = Invocation.FullMethodDesc (candidate);
 699
 700                         Expression invoke_method = Expression.MemberLookup (
 701                                 ec, type, "Invoke", MemberTypes.Method,
 702                                 Expression.AllBindingFlags, loc);
 703                         MethodBase method = ((MethodGroupExpr) invoke_method).Methods [0];
 704                         ParameterData param = Invocation.GetParameterData (method);
 705                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 706
 707                         if (!mg.HasTypeArguments &&
 708                             !Invocation.InferTypeArguments (ec, param, ref candidate))
 709                                 Report.Error (411, loc, "The type arguments for " +
 710                                               "method `{0}' cannot be infered from " +
 711                                               "the usage. Try specifying the type " +
 712                                               "arguments explicitly.", method_desc);
 713                         else
 714                                 Report.Error (123, loc, "Method '{0}' does not " +
 715                                               "match delegate '{1}'", method_desc,
 716                                               delegate_desc);
 717                 }
 718
 719                 public override void Emit (EmitContext ec)
 720                 {
 721                         if (method_group.InstanceExpression == null ||
 722                             delegate_method.IsStatic)
 723                                 ec.ig.Emit (OpCodes.Ldnull);
 724                         else
 725                                 method_group.InstanceExpression.Emit (ec);
 726
 727                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 728                                 ec.ig.Emit (OpCodes.Dup);
 729                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 730                         } else
 731                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 732                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 733                 }
 734
 735                 protected bool ResolveConstructorMethod (EmitContext ec)
 736                 {
 737                         Expression ml = Expression.MemberLookup (
 738                                 ec, type, ".ctor", loc);
 739
 740                         if (!(ml is MethodGroupExpr)) {
 741                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 742                                 return false;
 743                         }
 744
 745                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 746                         return true;
 747                 }
 748
 749                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 750                 {
 751                                 foreach (MethodInfo mi in mg.Methods){
 752                                         delegate_method = Delegate.VerifyMethod (
 753                                                 ec, type, mi, loc);
 754
 755                                         if (delegate_method != null)
 756                                                 break;
 757                                 }
 758
 759                                 if (delegate_method == null) {
 760                                         Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 761                                         return null;
 762                                 }
 763
 764                                 //
 765                                 // Check safe/unsafe of the delegate
 766                                 //
 767                                 if (!ec.InUnsafe){
 768                                         ParameterData param = Invocation.GetParameterData (delegate_method);
 769                                         int count = param.Count;
 770
 771                                         for (int i = 0; i < count; i++){
 772                                                 if (param.ParameterType (i).IsPointer){
 773                                                         Expression.UnsafeError (loc);
 774                                                         return null;
 775                                                 }
 776                                         }
 777                                 }
 778
 779                         //TODO: implement caching when performance will be low
 780                         IMethodData md = TypeManager.GetMethod (delegate_method);
 781                         if (md == null) {
 782                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 783                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 784                                 }
 785                         } else {
 786                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 787                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 788                                 }
 789                         }
 790
 791                                 if (mg.InstanceExpression != null)
 792                                 mg.InstanceExpression = mg.InstanceExpression.Resolve (ec);
 793                         else if (ec.IsStatic) {
 794                                 if (!delegate_method.IsStatic) {
 795                                                         Report.Error (120, loc,
 796                                                                       "An object reference is required for the non-static method " +
 797                                                                       delegate_method.Name);
 798                                                         return null;
 799                                                 }
 800                                 mg.InstanceExpression = null;
 801                                         } else
 802                                 mg.InstanceExpression = ec.GetThis (loc);
 803
 804                         if (mg.InstanceExpression != null && mg.InstanceExpression.Type.IsValueType)
 805                                 mg.InstanceExpression = new BoxedCast (mg.InstanceExpression);
 806
 807                         method_group = mg;
 808                                 eclass = ExprClass.Value;
 809                                 return this;
 810                         }
 811         }
 812
 813         //
 814         // Created from the conversion code
 815         //
 816         public class ImplicitDelegateCreation : DelegateCreation {
 817
 818                 ImplicitDelegateCreation (Type t, Location l)
 819                 {
 820                         type = t;
 821                         loc = l;
 822                 }
 823
 824                 public override Expression DoResolve (EmitContext ec)
 825                 {
 826                         return this;
 827                 }
 828
 829                 static public Expression Create (EmitContext ec, MethodGroupExpr mge, Type target_type, Location loc)
 830                 {
 831                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 832                         if (d.ResolveConstructorMethod (ec))
 833                                 return d.ResolveMethodGroupExpr (ec, mge);
 834                         else
 835                                 return null;
 836                 }
 837         }
 838
 839         //
 840         // A delegate-creation-expression, invoked from the `New' class
 841         //
 842         public class NewDelegate : DelegateCreation {
 843                 public ArrayList Arguments;
 844
 845                 //
 846                 // This constructor is invoked from the `New' expression
 847                 //
 848                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 849                 {
 850                         this.type = type;
 851                         this.Arguments = Arguments;
 852                         this.loc  = loc;
 853                 }
 854
 855                 public override Expression DoResolve (EmitContext ec)
 856                 {
 857                         if (Arguments == null || Arguments.Count != 1) {
 858                                 Report.Error (149, loc,
 859                                               "Method name expected");
 860                                 return null;
 861                         }
 862
 863                         if (!ResolveConstructorMethod (ec))
 864                                 return null;
 865
 866                         Argument a = (Argument) Arguments [0];
 867
 868                         if (!a.ResolveMethodGroup (ec, loc))
 869                                 return null;
 870
 871                         Expression e = a.Expr;
 872
 873                         MethodGroupExpr mg = e as MethodGroupExpr;
 874                         if (mg != null)
 875                                 return ResolveMethodGroupExpr (ec, mg);
 876
 877                         Type e_type = e.Type;
 878
 879                         if (!TypeManager.IsDelegateType (e_type)) {
 880                                 e.Error_UnexpectedKind ("method");
 881                                 return null;
 882                         }
 883
 884                         method_group = Expression.MemberLookup (
 885                                 ec, type, "Invoke", MemberTypes.Method,
 886                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 887
 888                         if (method_group == null) {
 889                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 890                                 return null;
 891                         }
 892
 893                         // This is what MS' compiler reports. We could always choose
 894                         // to be more verbose and actually give delegate-level specifics
 895                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 896                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 897                                               "to type '" + type + "'");
 898                                 return null;
 899                         }
 900
 901                         method_group.InstanceExpression = e;
 902                         delegate_method = method_group.Methods [0];
 903
 904                         eclass = ExprClass.Value;
 905                         return this;
 906                 }
 907         }
 908
 909         public class DelegateInvocation : ExpressionStatement {
 910
 911                 public Expression InstanceExpr;
 912                 public ArrayList  Arguments;
 913
 914                 MethodBase method;
 915
 916                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 917                 {
 918                         this.InstanceExpr = instance_expr;
 919                         this.Arguments = args;
 920                         this.loc = loc;
 921                 }
 922
 923                 public override Expression DoResolve (EmitContext ec)
 924                 {
 925                         if (InstanceExpr is EventExpr) {
 926
 927                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 928
 929                                 Expression ml = MemberLookup (
 930                                         ec, ec.ContainerType, ei.Name,
 931                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 932
 933                                 if (ml == null) {
 934                                         //
 935                                         // If this is the case, then the Event does not belong
 936                                         // to this Type and so, according to the spec
 937                                         // cannot be accessed directly
 938                                         //
 939                                         // Note that target will not appear as an EventExpr
 940                                         // in the case it is being referenced within the same type container;
 941                                         // it will appear as a FieldExpr in that case.
 942                                         //
 943
 944                                         Assign.error70 (ei, loc);
 945                                         return null;
 946                                 }
 947                         }
 948
 949
 950                         Type del_type = InstanceExpr.Type;
 951                         if (del_type == null)
 952                                 return null;
 953
 954                         if (Arguments != null){
 955                                 foreach (Argument a in Arguments){
 956                                         if (!a.Resolve (ec, loc))
 957                                                 return null;
 958                                 }
 959                         }
 960
 961                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 962                                 return null;
 963
 964                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
 965                         if (!(lookup is MethodGroupExpr)) {
 966                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 967                                 return null;
 968                         }
 969
 970                         method = ((MethodGroupExpr) lookup).Methods [0];
 971                         type = ((MethodInfo) method).ReturnType;
 972                         eclass = ExprClass.Value;
 973
 974                         return this;
 975                 }
 976
 977                 public override void Emit (EmitContext ec)
 978                 {
 979                         //
 980                         // Invocation on delegates call the virtual Invoke member
 981                         // so we are always `instance' calls
 982                         //
 983                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
 984                 }
 985
 986                 public override void EmitStatement (EmitContext ec)
 987                 {
 988                         Emit (ec);
 989                         //
 990                         // Pop the return value if there is one
 991                         //
 992                         if (method is MethodInfo){
 993                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
 994                                         ec.ig.Emit (OpCodes.Pop);
 995                         }
 996                 }
 997
 998         }
 999 }