mcs/mcs/delegate.cs

   1 //
   2 // delegate.cs: Delegate Handler
   3 //
   4 // Authors:
   5 //     Ravi Pratap (ravi@ximian.com)
   6 //     Miguel de Icaza (miguel@ximian.com)
   7 //
   8 // Licensed under the terms of the GNU GPL
   9 //
  10 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  11 //
  12 //
  13
  14 using System;
  15 using System.Collections;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.Text;
  19
  20 namespace Mono.CSharp {
  21
  22         /// <summary>
  23         ///   Holds Delegates
  24         /// </summary>
  25         public class Delegate : DeclSpace {
  26                 public Expression ReturnType;
  27                 public Parameters      Parameters;
  28
  29                 public ConstructorBuilder ConstructorBuilder;
  30                 public MethodBuilder      InvokeBuilder;
  31                 public MethodBuilder      BeginInvokeBuilder;
  32                 public MethodBuilder      EndInvokeBuilder;
  33
  34                 Type [] param_types;
  35                 Type ret_type;
  36
  37                 static string[] attribute_targets = new string [] { "type", "return" };
  38
  39                 Expression instance_expr;
  40                 MethodBase delegate_method;
  41                 ReturnParameter return_attributes;
  42
  43                 const int AllowedModifiers =
  44                         Modifiers.NEW |
  45                         Modifiers.PUBLIC |
  46                         Modifiers.PROTECTED |
  47                         Modifiers.INTERNAL |
  48                         Modifiers.UNSAFE |
  49                         Modifiers.PRIVATE;
  50
  51                 public Delegate (NamespaceEntry ns, TypeContainer parent, Expression type,
  52                                  int mod_flags, MemberName name, Parameters param_list,
  53                                  Attributes attrs, Location l)
  54                         : base (ns, parent, name, attrs, l)
  55
  56                 {
  57                         this.ReturnType = type;
  58                         ModFlags        = Modifiers.Check (AllowedModifiers, mod_flags,
  59                                                            IsTopLevel ? Modifiers.INTERNAL :
  60                                                            Modifiers.PRIVATE, l);
  61                         Parameters      = param_list;
  62                 }
  63
  64                 public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
  65                 {
  66                         if (a.Target == AttributeTargets.ReturnValue) {
  67                                 if (return_attributes == null)
  68                                         return_attributes = new ReturnParameter (InvokeBuilder, Location);
  69
  70                                 return_attributes.ApplyAttributeBuilder (a, cb);
  71                                 return;
  72                         }
  73
  74                         base.ApplyAttributeBuilder (a, cb);
  75                 }
  76
  77                 public override TypeBuilder DefineType ()
  78                 {
  79                         if (TypeBuilder != null)
  80                                 return TypeBuilder;
  81
  82                         ec = new EmitContext (this, this, Location, null, null, ModFlags, false);
  83
  84                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel) |
  85                                 TypeAttributes.Class | TypeAttributes.Sealed;
  86
  87                         if (IsTopLevel) {
  88                                 if (TypeManager.NamespaceClash (Name, Location))
  89                                         return null;
  90
  91                                 ModuleBuilder builder = CodeGen.Module.Builder;
  92
  93                                 TypeBuilder = builder.DefineType (
  94                                         Name, attr, TypeManager.multicast_delegate_type);
  95                         } else {
  96                                 TypeBuilder builder = Parent.TypeBuilder;
  97
  98                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
  99                                 TypeBuilder = builder.DefineNestedType (
 100                                         name, attr, TypeManager.multicast_delegate_type);
 101                         }
 102
 103                         TypeManager.AddDelegateType (Name, TypeBuilder, this);
 104
 105                         return TypeBuilder;
 106                 }
 107
 108                 public override bool DefineMembers (TypeContainer container)
 109                 {
 110                         return true;
 111                 }
 112
 113                 public override bool Define ()
 114                 {
 115                         MethodAttributes mattr;
 116                         int i;
 117                         ec = new EmitContext (this, this, Location, null, null, ModFlags, false);
 118
 119                         // FIXME: POSSIBLY make this static, as it is always constant
 120                         //
 121                         Type [] const_arg_types = new Type [2];
 122                         const_arg_types [0] = TypeManager.object_type;
 123                         const_arg_types [1] = TypeManager.intptr_type;
 124
 125                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 126                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 127
 128                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 129                                                                             CallingConventions.Standard,
 130                                                                             const_arg_types);
 131
 132                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 133                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 134                         //
 135                         // HACK because System.Reflection.Emit is lame
 136                         //
 137                         //
 138                         // FIXME: POSSIBLY make these static, as they are always the same
 139                         Parameter [] fixed_pars = new Parameter [2];
 140                         fixed_pars [0] = new Parameter (TypeManager.system_object_expr, "object",
 141                                                         Parameter.Modifier.NONE, null);
 142                         fixed_pars [1] = new Parameter (TypeManager.system_intptr_expr, "method",
 143                                                         Parameter.Modifier.NONE, null);
 144                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);
 145
 146                         TypeManager.RegisterMethod (
 147                                 ConstructorBuilder,
 148                                 new InternalParameters (const_arg_types, const_parameters),
 149                                 const_arg_types);
 150
 151
 152                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 153
 154                         //
 155                         // Here the various methods like Invoke, BeginInvoke etc are defined
 156                         //
 157                         // First, call the `out of band' special method for
 158                         // defining recursively any types we need:
 159
 160                         if (!Parameters.ComputeAndDefineParameterTypes (ec))
 161                                 return false;
 162
 163                         param_types = Parameters.GetParameterInfo (ec);
 164                         if (param_types == null)
 165                                 return false;
 166
 167                         //
 168                         // Invoke method
 169                         //
 170
 171                         // Check accessibility
 172                         foreach (Type partype in param_types){
 173                                 if (!Parent.AsAccessible (partype, ModFlags)) {
 174                                         Report.Error (59, Location,
 175                                                       "Inconsistent accessibility: parameter type `" +
 176                                                       TypeManager.CSharpName (partype) + "` is less " +
 177                                                       "accessible than delegate `" + Name + "'");
 178                                         return false;
 179                                 }
 180                                 if (partype.IsPointer && !UnsafeOK (Parent))
 181                                         return false;
 182                         }
 183
 184                         ReturnType = ReturnType.ResolveAsTypeTerminal (ec, false);
 185                         if (ReturnType == null)
 186                             return false;
 187
 188                         ret_type = ReturnType.Type;
 189                         if (ret_type == null)
 190                                 return false;
 191
 192                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 193                                 Report.Error (58, Location,
 194                                               "Inconsistent accessibility: return type `" +
 195                                               TypeManager.CSharpName (ret_type) + "` is less " +
 196                                               "accessible than delegate `" + Name + "'");
 197                                 return false;
 198                         }
 199
 200                         if (ret_type.IsPointer && !UnsafeOK (Parent))
 201                                 return false;
 202
 203                         //
 204                         // We don't have to check any others because they are all
 205                         // guaranteed to be accessible - they are standard types.
 206                         //
 207
 208                         CallingConventions cc = Parameters.GetCallingConvention ();
 209
 210                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 211
 212                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 213                                                                   mattr,
 214                                                                   cc,
 215                                                                   ret_type,
 216                                                                   param_types);
 217
 218                         //
 219                         // Define parameters, and count out/ref parameters
 220                         //
 221                         int out_params = 0;
 222                         i = 0;
 223                         if (Parameters.FixedParameters != null){
 224                                 int top = Parameters.FixedParameters.Length;
 225                                 Parameter p;
 226
 227                                 for (; i < top; i++) {
 228                                         p = Parameters.FixedParameters [i];
 229                                         p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 230
 231                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 232                                                 out_params++;
 233                                 }
 234                         }
 235                         if (Parameters.ArrayParameter != null){
 236                                 Parameter p = Parameters.ArrayParameter;
 237                                 p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 238                         }
 239
 240                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 241
 242                         TypeManager.RegisterMethod (InvokeBuilder,
 243                                                     new InternalParameters (param_types, Parameters),
 244                                                     param_types);
 245
 246                         //
 247                         // BeginInvoke
 248                         //
 249                         int params_num = param_types.Length;
 250                         Type [] async_param_types = new Type [params_num + 2];
 251
 252                         param_types.CopyTo (async_param_types, 0);
 253
 254                         async_param_types [params_num] = TypeManager.asynccallback_type;
 255                         async_param_types [params_num + 1] = TypeManager.object_type;
 256
 257                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 258                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 259
 260                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 261                                                                        mattr,
 262                                                                        cc,
 263                                                                        TypeManager.iasyncresult_type,
 264                                                                        async_param_types);
 265
 266                         i = 0;
 267                         if (Parameters.FixedParameters != null){
 268                                 int top = Parameters.FixedParameters.Length;
 269                                 Parameter p;
 270
 271                                 for (i = 0 ; i < top; i++) {
 272                                         p = Parameters.FixedParameters [i];
 273
 274                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 275                                 }
 276                         }
 277                         if (Parameters.ArrayParameter != null){
 278                                 Parameter p = Parameters.ArrayParameter;
 279                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 280
 281                                 i++;
 282                         }
 283
 284                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 285                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 286
 287                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 288
 289                         Parameter [] async_params = new Parameter [params_num + 2];
 290                         int n = 0;
 291                         if (Parameters.FixedParameters != null){
 292                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 293                                 n = Parameters.FixedParameters.Length;
 294                         }
 295                         if (Parameters.ArrayParameter != null)
 296                                 async_params [n] = Parameters.ArrayParameter;
 297
 298                         async_params [params_num] = new Parameter (
 299                                 TypeManager.system_asynccallback_expr, "callback",
 300                                                                    Parameter.Modifier.NONE, null);
 301                         async_params [params_num + 1] = new Parameter (
 302                                 TypeManager.system_object_expr, "object",
 303                                                                    Parameter.Modifier.NONE, null);
 304
 305                         Parameters async_parameters = new Parameters (async_params, null, Location);
 306                         async_parameters.ComputeAndDefineParameterTypes (ec);
 307
 308                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 309                                                     new InternalParameters (async_param_types, async_parameters),
 310                                                     async_param_types);
 311
 312                         //
 313                         // EndInvoke is a bit more interesting, all the parameters labeled as
 314                         // out or ref have to be duplicated here.
 315                         //
 316
 317                         Type [] end_param_types = new Type [out_params + 1];
 318                         Parameter [] end_params = new Parameter [out_params + 1];
 319                         int param = 0;
 320                         if (out_params > 0){
 321                                 int top = Parameters.FixedParameters.Length;
 322                                 for (i = 0; i < top; i++){
 323                                         Parameter p = Parameters.FixedParameters [i];
 324                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 325                                                 continue;
 326
 327                                         end_param_types [param] = param_types [i];
 328                                         end_params [param] = p;
 329                                         param++;
 330                                 }
 331                         }
 332                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 333                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 334
 335                         //
 336                         // Create method, define parameters, register parameters with type system
 337                         //
 338                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 339                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 340
 341                         //
 342                         // EndInvoke: Label the parameters
 343                         //
 344                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 345                         for (i = 0; i < end_params.Length-1; i++){
 346                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 347                         }
 348
 349                         Parameters end_parameters = new Parameters (end_params, null, Location);
 350                         end_parameters.ComputeAndDefineParameterTypes (ec);
 351
 352                         TypeManager.RegisterMethod (
 353                                 EndInvokeBuilder,
 354                                 new InternalParameters (end_param_types, end_parameters),
 355                                 end_param_types);
 356
 357                         return true;
 358                 }
 359
 360                 public override void Emit ()
 361                 {
 362                         if (OptAttributes != null) {
 363                                 Parameters.LabelParameters (ec, InvokeBuilder, Location);
 364                                 OptAttributes.Emit (ec, this);
 365                         }
 366
 367                         base.Emit ();
 368                 }
 369
 370                 public override string[] ValidAttributeTargets {
 371                         get {
 372                                 return attribute_targets;
 373                         }
 374                 }
 375
 376                 //TODO: duplicate
 377                 protected override bool VerifyClsCompliance (DeclSpace ds)
 378                 {
 379                         if (!base.VerifyClsCompliance (ds)) {
 380                                 return false;
 381                         }
 382
 383                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 384
 385                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 386                                 Report.Error (3002, Location, "Return type of '{0}' is not CLS-compliant", GetSignatureForError ());
 387                         }
 388                         return true;
 389                 }
 390
 391                 //
 392                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 393                 // to extract the signature of a delegate.
 394                 //
 395                 public static MethodInfo GetInvokeMethod (EmitContext ec, Type delegate_type, Location loc)
 396                 {
 397                         Expression ml = Expression.MemberLookup (
 398                                 ec, delegate_type, "Invoke", loc);
 399
 400                         if (!(ml is MethodGroupExpr)) {
 401                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 402                                 return null;
 403                         }
 404
 405                         return (MethodInfo) (((MethodGroupExpr) ml).Methods [0]);
 406                 }
 407
 408                 /// <summary>
 409                 ///  Verifies whether the method in question is compatible with the delegate
 410                 ///  Returns the method itself if okay and null if not.
 411                 /// </summary>
 412                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 413                                                        Location loc)
 414                 {
 415                         ParameterData pd = Invocation.GetParameterData (mb);
 416
 417                         int pd_count = pd.Count;
 418
 419                         MethodBase invoke_mb = GetInvokeMethod (ec, delegate_type, loc);
 420                         if (invoke_mb == null)
 421                                 return null;
 422
 423                         ParameterData invoke_pd = Invocation.GetParameterData (invoke_mb);
 424
 425                         if (invoke_pd.Count != pd_count)
 426                                 return null;
 427
 428                         for (int i = pd_count; i > 0; ) {
 429                                 i--;
 430
 431                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 432                                 Type pd_type = pd.ParameterType (i);
 433                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 434                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 435
 436                                 if (invoke_pd_type == pd_type &&
 437                                     invoke_pd_type_mod == pd_type_mod)
 438                                         continue;
 439
 440                                 if (invoke_pd_type.IsSubclassOf (pd_type) &&
 441                                                 invoke_pd_type_mod == pd_type_mod)
 442                                         if (RootContext.Version == LanguageVersion.ISO_1) {
 443                                                 Report.FeatureIsNotStandardized (loc, "contravariance");
 444                                                 return null;
 445                                         } else
 446                                                 continue;
 447
 448                                 return null;
 449                         }
 450
 451                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 452                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 453                         if (invoke_mb_retval == mb_retval)
 454                                 return mb;
 455
 456                         if (mb_retval.IsSubclassOf (invoke_mb_retval))
 457                                 if (RootContext.Version == LanguageVersion.ISO_1) {
 458                                         Report.FeatureIsNotStandardized (loc, "covariance");
 459                                         return null;
 460                                 }
 461                                 else
 462                                         return mb;
 463
 464                         return null;
 465                 }
 466
 467                 // <summary>
 468                 //  Verifies whether the invocation arguments are compatible with the
 469                 //  delegate's target method
 470                 // </summary>
 471                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 472                                                         ArrayList args, Location loc)
 473                 {
 474                         int arg_count;
 475
 476                         if (args == null)
 477                                 arg_count = 0;
 478                         else
 479                                 arg_count = args.Count;
 480
 481                         Expression ml = Expression.MemberLookup (
 482                                 ec, delegate_type, "Invoke", loc);
 483
 484                         if (!(ml is MethodGroupExpr)) {
 485                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 486                                 return false;
 487                         }
 488
 489                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 490                         ParameterData pd = Invocation.GetParameterData (mb);
 491
 492                         int pd_count = pd.Count;
 493
 494                         bool params_method = (pd_count != 0) &&
 495                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 496
 497                         if (!params_method && pd_count != arg_count) {
 498                                 Report.Error (1593, loc,
 499                                               "Delegate '{0}' does not take {1} arguments",
 500                                               delegate_type.ToString (), arg_count);
 501                                 return false;
 502                         }
 503
 504                         //
 505                         // Consider the case:
 506                         //   delegate void FOO(param object[] args);
 507                         //   FOO f = new FOO(...);
 508                         //   f(new object[] {1, 2, 3});
 509                         //
 510                         // This should be treated like f(1,2,3).  This is done by ignoring the
 511                         // 'param' modifier for that invocation.  If that fails, then the
 512                         // 'param' modifier is considered.
 513                         //
 514                         // One issue is that 'VerifyArgumentsCompat' modifies the elements of
 515                         // the 'args' array.  However, the modifications appear idempotent.
 516                         // Normal 'Invocation's also have the same behaviour, implicitly.
 517                         //
 518
 519                         bool ans = false;
 520                         if (arg_count == pd_count)
 521                                 ans = Invocation.VerifyArgumentsCompat (
 522                                         ec, args, arg_count, mb, false,
 523                                         delegate_type, false, loc);
 524                         if (!ans && params_method)
 525                                 ans = Invocation.VerifyArgumentsCompat (
 526                                         ec, args, arg_count, mb, true,
 527                                         delegate_type, false, loc);
 528                         return ans;
 529                 }
 530
 531                 /// <summary>
 532                 ///  Verifies whether the delegate in question is compatible with this one in
 533                 ///  order to determine if instantiation from the same is possible.
 534                 /// </summary>
 535                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 536                 {
 537                         Expression ml = Expression.MemberLookup (
 538                                 ec, delegate_type, "Invoke", loc);
 539
 540                         if (!(ml is MethodGroupExpr)) {
 541                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 542                                 return false;
 543                         }
 544
 545                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 546                         ParameterData pd = Invocation.GetParameterData (mb);
 547
 548                         Expression probe_ml = Expression.MemberLookup (
 549                                 ec, delegate_type, "Invoke", loc);
 550
 551                         if (!(probe_ml is MethodGroupExpr)) {
 552                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 553                                 return false;
 554                         }
 555
 556                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 557                         ParameterData probe_pd = Invocation.GetParameterData (probe_mb);
 558
 559                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 560                                 return false;
 561
 562                         if (pd.Count != probe_pd.Count)
 563                                 return false;
 564
 565                         for (int i = pd.Count; i > 0; ) {
 566                                 i--;
 567
 568                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 569                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 570                                         return false;
 571                         }
 572
 573                         return true;
 574                 }
 575
 576                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 577                 {
 578                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 579
 580                         sb.Append (" " + del_type.ToString ());
 581                         sb.Append (" (");
 582
 583                         int length = pd.Count;
 584
 585                         for (int i = length; i > 0; ) {
 586                                 i--;
 587
 588                                 sb.Append (pd.ParameterDesc (length - i - 1));
 589                                 if (i != 0)
 590                                         sb.Append (", ");
 591                         }
 592
 593                         sb.Append (")");
 594                         return sb.ToString ();
 595
 596                 }
 597
 598                 // Hack around System.Reflection as found everywhere else
 599                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 600                                                         MemberFilter filter, object criteria)
 601                 {
 602                         ArrayList members = new ArrayList ();
 603
 604                         if ((mt & MemberTypes.Method) != 0) {
 605                                 if (ConstructorBuilder != null)
 606                                 if (filter (ConstructorBuilder, criteria))
 607                                         members.Add (ConstructorBuilder);
 608
 609                                 if (InvokeBuilder != null)
 610                                 if (filter (InvokeBuilder, criteria))
 611                                         members.Add (InvokeBuilder);
 612
 613                                 if (BeginInvokeBuilder != null)
 614                                 if (filter (BeginInvokeBuilder, criteria))
 615                                         members.Add (BeginInvokeBuilder);
 616
 617                                 if (EndInvokeBuilder != null)
 618                                 if (filter (EndInvokeBuilder, criteria))
 619                                         members.Add (EndInvokeBuilder);
 620                         }
 621
 622                         return new MemberList (members);
 623                 }
 624
 625                 public override MemberCache MemberCache {
 626                         get {
 627                                 return null;
 628                         }
 629                 }
 630
 631                 public Expression InstanceExpression {
 632                         get {
 633                                 return instance_expr;
 634                         }
 635                         set {
 636                                 instance_expr = value;
 637                         }
 638                 }
 639
 640                 public MethodBase TargetMethod {
 641                         get {
 642                                 return delegate_method;
 643                         }
 644                         set {
 645                                 delegate_method = value;
 646                         }
 647                 }
 648
 649                 public Type TargetReturnType {
 650                         get {
 651                                 return ret_type;
 652                         }
 653                 }
 654
 655                 public Type [] ParameterTypes {
 656                         get {
 657                                 return param_types;
 658                         }
 659                 }
 660
 661                 public override AttributeTargets AttributeTargets {
 662                         get {
 663                                 return AttributeTargets.Delegate;
 664                         }
 665                 }
 666
 667                 //
 668                 //   Represents header string for documentation comment.
 669                 //
 670                 public override string DocCommentHeader {
 671                         get { return "T:"; }
 672                 }
 673
 674                 protected override void VerifyObsoleteAttribute()
 675                 {
 676                         CheckUsageOfObsoleteAttribute (ret_type);
 677
 678                         foreach (Type type in param_types) {
 679                                 CheckUsageOfObsoleteAttribute (type);
 680                         }
 681                 }
 682         }
 683
 684         //
 685         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 686         //
 687         public abstract class DelegateCreation : Expression {
 688                 protected MethodBase constructor_method;
 689                 protected MethodBase delegate_method;
 690                 protected MethodGroupExpr method_group;
 691                 protected Expression delegate_instance_expression;
 692
 693                 public DelegateCreation () {}
 694
 695                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 696                 {
 697                         string method_desc;
 698
 699                         if (mg.Methods.Length > 1)
 700                                 method_desc = mg.Methods [0].Name;
 701                         else
 702                                 method_desc = Invocation.FullMethodDesc (mg.Methods [0]);
 703
 704                         Expression invoke_method = Expression.MemberLookup (
 705                                 ec, type, "Invoke", MemberTypes.Method,
 706                                 Expression.AllBindingFlags, loc);
 707                         MethodBase method = ((MethodGroupExpr) invoke_method).Methods [0];
 708                         ParameterData param = Invocation.GetParameterData (method);
 709                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 710
 711                         Report.Error (123, loc, "Method '" + method_desc + "' does not " +
 712                                       "match delegate '" + delegate_desc + "'");
 713                 }
 714
 715                 public override void Emit (EmitContext ec)
 716                 {
 717                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 718                                 ec.ig.Emit (OpCodes.Ldnull);
 719                         else
 720                                 delegate_instance_expression.Emit (ec);
 721
 722                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 723                                 ec.ig.Emit (OpCodes.Dup);
 724                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 725                         } else
 726                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 727                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 728                 }
 729
 730                 protected bool ResolveConstructorMethod (EmitContext ec)
 731                 {
 732                         Expression ml = Expression.MemberLookup (
 733                                 ec, type, ".ctor", loc);
 734
 735                         if (!(ml is MethodGroupExpr)) {
 736                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 737                                 return false;
 738                         }
 739
 740                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 741                         return true;
 742                 }
 743
 744                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 745                 {
 746                         foreach (MethodInfo mi in mg.Methods){
 747                                 delegate_method  = Delegate.VerifyMethod (ec, type, mi, loc);
 748
 749                                 if (delegate_method != null)
 750                                         break;
 751                         }
 752
 753                         if (delegate_method == null) {
 754                                 Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 755                                 return null;
 756                         }
 757
 758                         //
 759                         // Check safe/unsafe of the delegate
 760                         //
 761                         if (!ec.InUnsafe){
 762                                 ParameterData param = Invocation.GetParameterData (delegate_method);
 763                                 int count = param.Count;
 764
 765                                 for (int i = 0; i < count; i++){
 766                                         if (param.ParameterType (i).IsPointer){
 767                                                 Expression.UnsafeError (loc);
 768                                                 return null;
 769                                         }
 770                                 }
 771                         }
 772
 773                         //TODO: implement caching when performance will be low
 774                         IMethodData md = TypeManager.GetMethod (delegate_method);
 775                         if (md == null) {
 776                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 777                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 778                                 }
 779                         } else {
 780                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 781                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 782                                 }
 783                         }
 784
 785                         if (mg.InstanceExpression != null)
 786                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 787                         else if (ec.IsStatic) {
 788                                 if (!delegate_method.IsStatic) {
 789                                         Report.Error (120, loc,
 790                                                       "An object reference is required for the non-static method " +
 791                                                       delegate_method.Name);
 792                                         return null;
 793                                 }
 794                                 delegate_instance_expression = null;
 795                         } else
 796                                 delegate_instance_expression = ec.GetThis (loc);
 797
 798                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 799                                 delegate_instance_expression = new BoxedCast (delegate_instance_expression);
 800
 801                         method_group = mg;
 802                         eclass = ExprClass.Value;
 803                         return this;
 804                 }
 805         }
 806
 807         //
 808         // Created from the conversion code
 809         //
 810         public class ImplicitDelegateCreation : DelegateCreation {
 811
 812                 ImplicitDelegateCreation (Type t, Location l)
 813                 {
 814                         type = t;
 815                         loc = l;
 816                 }
 817
 818                 public override Expression DoResolve (EmitContext ec)
 819                 {
 820                         return this;
 821                 }
 822
 823                 static public Expression Create (EmitContext ec, MethodGroupExpr mge, Type target_type, Location loc)
 824                 {
 825                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 826                         if (d.ResolveConstructorMethod (ec))
 827                                 return d.ResolveMethodGroupExpr (ec, mge);
 828                         else
 829                                 return null;
 830                 }
 831         }
 832
 833         //
 834         // A delegate-creation-expression, invoked from the `New' class
 835         //
 836         public class NewDelegate : DelegateCreation {
 837                 public ArrayList Arguments;
 838
 839                 //
 840                 // This constructor is invoked from the `New' expression
 841                 //
 842                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 843                 {
 844                         this.type = type;
 845                         this.Arguments = Arguments;
 846                         this.loc  = loc;
 847                 }
 848
 849                 public override Expression DoResolve (EmitContext ec)
 850                 {
 851                         if (Arguments == null || Arguments.Count != 1) {
 852                                 Report.Error (149, loc,
 853                                               "Method name expected");
 854                                 return null;
 855                         }
 856
 857                         if (!ResolveConstructorMethod (ec))
 858                                 return null;
 859
 860                         Argument a = (Argument) Arguments [0];
 861
 862                         if (!a.ResolveMethodGroup (ec, loc))
 863                                 return null;
 864
 865                         Expression e = a.Expr;
 866
 867                         if (e is AnonymousMethod && RootContext.Version != LanguageVersion.ISO_1)
 868                                 return ((AnonymousMethod) e).Compatible (ec, type, false);
 869
 870                         MethodGroupExpr mg = e as MethodGroupExpr;
 871                         if (mg != null)
 872                                 return ResolveMethodGroupExpr (ec, mg);
 873
 874                         Type e_type = e.Type;
 875
 876                         if (!TypeManager.IsDelegateType (e_type)) {
 877                                 Report.Error (149, loc, "Method name expected");
 878                                 return null;
 879                         }
 880
 881                         method_group = Expression.MemberLookup (
 882                                 ec, type, "Invoke", MemberTypes.Method,
 883                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 884
 885                         if (method_group == null) {
 886                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 887                                 return null;
 888                         }
 889
 890                         // This is what MS' compiler reports. We could always choose
 891                         // to be more verbose and actually give delegate-level specifics
 892                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 893                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 894                                               "to type '" + type + "'");
 895                                 return null;
 896                         }
 897
 898                         delegate_instance_expression = e;
 899                         delegate_method = method_group.Methods [0];
 900
 901                         eclass = ExprClass.Value;
 902                         return this;
 903                 }
 904         }
 905
 906         public class DelegateInvocation : ExpressionStatement {
 907
 908                 public Expression InstanceExpr;
 909                 public ArrayList  Arguments;
 910
 911                 MethodBase method;
 912
 913                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 914                 {
 915                         this.InstanceExpr = instance_expr;
 916                         this.Arguments = args;
 917                         this.loc = loc;
 918                 }
 919
 920                 public override Expression DoResolve (EmitContext ec)
 921                 {
 922                         if (InstanceExpr is EventExpr) {
 923
 924                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 925
 926                                 Expression ml = MemberLookup (
 927                                         ec, ec.ContainerType, ei.Name,
 928                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 929
 930                                 if (ml == null) {
 931                                         //
 932                                         // If this is the case, then the Event does not belong
 933                                         // to this Type and so, according to the spec
 934                                         // cannot be accessed directly
 935                                         //
 936                                         // Note that target will not appear as an EventExpr
 937                                         // in the case it is being referenced within the same type container;
 938                                         // it will appear as a FieldExpr in that case.
 939                                         //
 940
 941                                         Assign.error70 (ei, loc);
 942                                         return null;
 943                                 }
 944                         }
 945
 946
 947                         Type del_type = InstanceExpr.Type;
 948                         if (del_type == null)
 949                                 return null;
 950
 951                         if (Arguments != null){
 952                                 foreach (Argument a in Arguments){
 953                                         if (!a.Resolve (ec, loc))
 954                                                 return null;
 955                                 }
 956                         }
 957
 958                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
 959                                 return null;
 960
 961                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
 962                         if (!(lookup is MethodGroupExpr)) {
 963                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 964                                 return null;
 965                         }
 966
 967                         method = ((MethodGroupExpr) lookup).Methods [0];
 968                         type = ((MethodInfo) method).ReturnType;
 969                         eclass = ExprClass.Value;
 970
 971                         return this;
 972                 }
 973
 974                 public override void Emit (EmitContext ec)
 975                 {
 976                         //
 977                         // Invocation on delegates call the virtual Invoke member
 978                         // so we are always `instance' calls
 979                         //
 980                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
 981                 }
 982
 983                 public override void EmitStatement (EmitContext ec)
 984                 {
 985                         Emit (ec);
 986                         //
 987                         // Pop the return value if there is one
 988                         //
 989                         if (method is MethodInfo){
 990                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
 991                                         ec.ig.Emit (OpCodes.Pop);
 992                         }
 993                 }
 994
 995         }
 996 }