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                         ec = new EmitContext (this, this, Location, null, null, ModFlags, false);
  83
  84                         if (IsGeneric) {
  85                                 foreach (TypeParameter type_param in TypeParameters)
  86                                         if (!type_param.Resolve (this))
  87                                                 return null;
  88                         }
  89
  90                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel) |
  91                                 TypeAttributes.Class | TypeAttributes.Sealed;
  92
  93                         if (TypeManager.multicast_delegate_type == null)
  94                                 Report.Error (-100, Location, "Internal error: delegate used before " +
  95                                               "System.MulticastDelegate is resolved.  This can only " +
  96                                               "happen during corlib compilation, when using a delegate " +
  97                                               "in any of the `core' classes.  See bug #72015 for details.");
  98
  99                         if (IsTopLevel) {
 100                                 if (TypeManager.NamespaceClash (Name, Location))
 101                                         return null;
 102
 103                                 ModuleBuilder builder = CodeGen.Module.Builder;
 104
 105                                 TypeBuilder = builder.DefineType (
 106                                         Name, attr, TypeManager.multicast_delegate_type);
 107                         } else {
 108                                 TypeBuilder builder = Parent.TypeBuilder;
 109
 110                                 string name = Name.Substring (1 + Name.LastIndexOf ('.'));
 111                                 TypeBuilder = builder.DefineNestedType (
 112                                         name, attr, TypeManager.multicast_delegate_type);
 113                         }
 114
 115                         TypeManager.AddDelegateType (Name, TypeBuilder, this);
 116
 117                         if (IsGeneric) {
 118                                 string[] param_names = new string [TypeParameters.Length];
 119                                 for (int i = 0; i < TypeParameters.Length; i++)
 120                                         param_names [i] = TypeParameters [i].Name;
 121
 122                                 GenericTypeParameterBuilder[] gen_params;
 123                                 gen_params = TypeBuilder.DefineGenericParameters (param_names);
 124
 125                                 int offset = CountTypeParameters - CurrentTypeParameters.Length;
 126                                 for (int i = offset; i < gen_params.Length; i++)
 127                                         CurrentTypeParameters [i - offset].Define (gen_params [i]);
 128
 129                                 foreach (TypeParameter type_param in CurrentTypeParameters) {
 130                                         if (!type_param.Resolve (this))
 131                                                 return null;
 132                                 }
 133
 134                                 for (int i = offset; i < gen_params.Length; i++)
 135                                         CurrentTypeParameters [i - offset].DefineConstraints ();
 136
 137                                 TypeExpr current = new ConstructedType (Name, TypeParameters, Location);
 138                                 current = current.ResolveAsTypeTerminal (ec);
 139                                 if (current == null)
 140                                         return null;
 141
 142                                 CurrentType = current.Type;
 143                         }
 144
 145                         return TypeBuilder;
 146                 }
 147
 148                 public override bool DefineMembers (TypeContainer container)
 149                 {
 150                         return true;
 151                 }
 152
 153                 public override bool Define ()
 154                 {
 155                         MethodAttributes mattr;
 156                         int i;
 157                         ec = new EmitContext (this, this, Location, null, null, ModFlags, false);
 158
 159                         if (IsGeneric) {
 160                                 foreach (TypeParameter type_param in TypeParameters)
 161                                         type_param.DefineType (ec);
 162                         }
 163
 164                         // FIXME: POSSIBLY make this static, as it is always constant
 165                         //
 166                         Type [] const_arg_types = new Type [2];
 167                         const_arg_types [0] = TypeManager.object_type;
 168                         const_arg_types [1] = TypeManager.intptr_type;
 169
 170                         mattr = MethodAttributes.RTSpecialName | MethodAttributes.SpecialName |
 171                                 MethodAttributes.HideBySig | MethodAttributes.Public;
 172
 173                         ConstructorBuilder = TypeBuilder.DefineConstructor (mattr,
 174                                                                             CallingConventions.Standard,
 175                                                                             const_arg_types);
 176
 177                         ConstructorBuilder.DefineParameter (1, ParameterAttributes.None, "object");
 178                         ConstructorBuilder.DefineParameter (2, ParameterAttributes.None, "method");
 179                         //
 180                         // HACK because System.Reflection.Emit is lame
 181                         //
 182                         //
 183                         // FIXME: POSSIBLY make these static, as they are always the same
 184                         Parameter [] fixed_pars = new Parameter [2];
 185                         fixed_pars [0] = new Parameter (TypeManager.system_object_expr, "object",
 186                                                         Parameter.Modifier.NONE, null);
 187                         fixed_pars [1] = new Parameter (TypeManager.system_intptr_expr, "method",
 188                                                         Parameter.Modifier.NONE, null);
 189                         Parameters const_parameters = new Parameters (fixed_pars, null, Location);
 190
 191                         TypeManager.RegisterMethod (
 192                                 ConstructorBuilder,
 193                                 new InternalParameters (const_arg_types, const_parameters),
 194                                 const_arg_types);
 195
 196
 197                         ConstructorBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 198
 199                         //
 200                         // Here the various methods like Invoke, BeginInvoke etc are defined
 201                         //
 202                         // First, call the `out of band' special method for
 203                         // defining recursively any types we need:
 204
 205                         if (!Parameters.ComputeAndDefineParameterTypes (ec))
 206                                 return false;
 207
 208                         param_types = Parameters.GetParameterInfo (ec);
 209                         if (param_types == null)
 210                                 return false;
 211
 212                         //
 213                         // Invoke method
 214                         //
 215
 216                         // Check accessibility
 217                         foreach (Type partype in param_types){
 218                                 if (!Parent.AsAccessible (partype, ModFlags)) {
 219                                         Report.Error (59, Location,
 220                                                       "Inconsistent accessibility: parameter type `" +
 221                                                       TypeManager.CSharpName (partype) + "` is less " +
 222                                                       "accessible than delegate `" + Name + "'");
 223                                         return false;
 224                                 }
 225                                 if (partype.IsPointer && !UnsafeOK (Parent))
 226                                         return false;
 227                         }
 228
 229                         ReturnType = ReturnType.ResolveAsTypeTerminal (ec);
 230                         if (ReturnType == null)
 231                             return false;
 232
 233                         ret_type = ReturnType.Type;
 234                         if (ret_type == null)
 235                                 return false;
 236
 237                         if (!Parent.AsAccessible (ret_type, ModFlags)) {
 238                                 Report.Error (58, Location,
 239                                               "Inconsistent accessibility: return type `" +
 240                                               TypeManager.CSharpName (ret_type) + "` is less " +
 241                                               "accessible than delegate `" + Name + "'");
 242                                 return false;
 243                         }
 244
 245                         if (ret_type.IsPointer && !UnsafeOK (Parent))
 246                                 return false;
 247
 248                         //
 249                         // We don't have to check any others because they are all
 250                         // guaranteed to be accessible - they are standard types.
 251                         //
 252
 253                         CallingConventions cc = Parameters.GetCallingConvention ();
 254
 255                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Virtual;
 256
 257                         InvokeBuilder = TypeBuilder.DefineMethod ("Invoke",
 258                                                                   mattr,
 259                                                                   cc,
 260                                                                   ret_type,
 261                                                                   param_types);
 262
 263                         //
 264                         // Define parameters, and count out/ref parameters
 265                         //
 266                         int out_params = 0;
 267                         i = 0;
 268                         if (Parameters.FixedParameters != null){
 269                                 int top = Parameters.FixedParameters.Length;
 270                                 Parameter p;
 271
 272                                 for (; i < top; i++) {
 273                                         p = Parameters.FixedParameters [i];
 274                                         p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 275
 276                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) != 0)
 277                                                 out_params++;
 278                                 }
 279                         }
 280                         if (Parameters.ArrayParameter != null){
 281                                 Parameter p = Parameters.ArrayParameter;
 282                                 p.DefineParameter (ec, InvokeBuilder, null, i + 1, Location);
 283                         }
 284
 285                         InvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 286
 287                         TypeManager.RegisterMethod (InvokeBuilder,
 288                                                     new InternalParameters (param_types, Parameters),
 289                                                     param_types);
 290
 291                         //
 292                         // BeginInvoke
 293                         //
 294                         int params_num = param_types.Length;
 295                         Type [] async_param_types = new Type [params_num + 2];
 296
 297                         param_types.CopyTo (async_param_types, 0);
 298
 299                         async_param_types [params_num] = TypeManager.asynccallback_type;
 300                         async_param_types [params_num + 1] = TypeManager.object_type;
 301
 302                         mattr = MethodAttributes.Public | MethodAttributes.HideBySig |
 303                                 MethodAttributes.Virtual | MethodAttributes.NewSlot;
 304
 305                         BeginInvokeBuilder = TypeBuilder.DefineMethod ("BeginInvoke",
 306                                                                        mattr,
 307                                                                        cc,
 308                                                                        TypeManager.iasyncresult_type,
 309                                                                        async_param_types);
 310
 311                         i = 0;
 312                         if (Parameters.FixedParameters != null){
 313                                 int top = Parameters.FixedParameters.Length;
 314                                 Parameter p;
 315
 316                                 for (i = 0 ; i < top; i++) {
 317                                         p = Parameters.FixedParameters [i];
 318
 319                                         p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 320                                 }
 321                         }
 322                         if (Parameters.ArrayParameter != null){
 323                                 Parameter p = Parameters.ArrayParameter;
 324                                 p.DefineParameter (ec, BeginInvokeBuilder, null, i + 1, Location);
 325
 326                                 i++;
 327                         }
 328
 329                         BeginInvokeBuilder.DefineParameter (i + 1, ParameterAttributes.None, "callback");
 330                         BeginInvokeBuilder.DefineParameter (i + 2, ParameterAttributes.None, "object");
 331
 332                         BeginInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 333
 334                         Parameter [] async_params = new Parameter [params_num + 2];
 335                         int n = 0;
 336                         if (Parameters.FixedParameters != null){
 337                                 Parameters.FixedParameters.CopyTo (async_params, 0);
 338                                 n = Parameters.FixedParameters.Length;
 339                         }
 340                         if (Parameters.ArrayParameter != null)
 341                                 async_params [n] = Parameters.ArrayParameter;
 342
 343                         async_params [params_num] = new Parameter (
 344                                 TypeManager.system_asynccallback_expr, "callback",
 345                                                                    Parameter.Modifier.NONE, null);
 346                         async_params [params_num + 1] = new Parameter (
 347                                 TypeManager.system_object_expr, "object",
 348                                                                    Parameter.Modifier.NONE, null);
 349
 350                         Parameters async_parameters = new Parameters (async_params, null, Location);
 351                         async_parameters.ComputeAndDefineParameterTypes (ec);
 352
 353                         TypeManager.RegisterMethod (BeginInvokeBuilder,
 354                                                     new InternalParameters (async_param_types, async_parameters),
 355                                                     async_param_types);
 356
 357                         //
 358                         // EndInvoke is a bit more interesting, all the parameters labeled as
 359                         // out or ref have to be duplicated here.
 360                         //
 361
 362                         Type [] end_param_types = new Type [out_params + 1];
 363                         Parameter [] end_params = new Parameter [out_params + 1];
 364                         int param = 0;
 365                         if (out_params > 0){
 366                                 int top = Parameters.FixedParameters.Length;
 367                                 for (i = 0; i < top; i++){
 368                                         Parameter p = Parameters.FixedParameters [i];
 369                                         if ((p.ModFlags & Parameter.Modifier.ISBYREF) == 0)
 370                                                 continue;
 371
 372                                         end_param_types [param] = param_types [i];
 373                                         end_params [param] = p;
 374                                         param++;
 375                                 }
 376                         }
 377                         end_param_types [out_params] = TypeManager.iasyncresult_type;
 378                         end_params [out_params] = new Parameter (TypeManager.system_iasyncresult_expr, "result", Parameter.Modifier.NONE, null);
 379
 380                         //
 381                         // Create method, define parameters, register parameters with type system
 382                         //
 383                         EndInvokeBuilder = TypeBuilder.DefineMethod ("EndInvoke", mattr, cc, ret_type, end_param_types);
 384                         EndInvokeBuilder.SetImplementationFlags (MethodImplAttributes.Runtime);
 385
 386                         //
 387                         // EndInvoke: Label the parameters
 388                         //
 389                         EndInvokeBuilder.DefineParameter (out_params + 1, ParameterAttributes.None, "result");
 390                         for (i = 0; i < end_params.Length-1; i++){
 391                                 EndInvokeBuilder.DefineParameter (i + 1, end_params [i].Attributes, end_params [i].Name);
 392                         }
 393
 394                         Parameters end_parameters = new Parameters (end_params, null, Location);
 395                         end_parameters.ComputeAndDefineParameterTypes (ec);
 396
 397                         TypeManager.RegisterMethod (
 398                                 EndInvokeBuilder,
 399                                 new InternalParameters (end_param_types, end_parameters),
 400                                 end_param_types);
 401
 402                         return true;
 403                 }
 404
 405                 public override void Emit ()
 406                 {
 407                         if (OptAttributes != null) {
 408                                 Parameters.LabelParameters (ec, InvokeBuilder, Location);
 409                                 OptAttributes.Emit (ec, this);
 410                         }
 411
 412                         base.Emit ();
 413                 }
 414
 415                 public override string[] ValidAttributeTargets {
 416                         get {
 417                                 return attribute_targets;
 418                         }
 419                 }
 420
 421                 //TODO: duplicate
 422                 protected override bool VerifyClsCompliance (DeclSpace ds)
 423                 {
 424                         if (!base.VerifyClsCompliance (ds)) {
 425                                 return false;
 426                         }
 427
 428                         AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);
 429
 430                         if (!AttributeTester.IsClsCompliant (ReturnType.Type)) {
 431                                 Report.Error (3002, Location, "Return type of '{0}' is not CLS-compliant", GetSignatureForError ());
 432                         }
 433                         return true;
 434                 }
 435
 436                 //
 437                 // Returns the MethodBase for "Invoke" from a delegate type, this is used
 438                 // to extract the signature of a delegate.
 439                 //
 440                 public static MethodGroupExpr GetInvokeMethod (EmitContext ec, Type delegate_type,
 441                                                        Location loc)
 442                 {
 443                         Expression ml = Expression.MemberLookup (
 444                                 ec, delegate_type, "Invoke", loc);
 445
 446                         MethodGroupExpr mg = ml as MethodGroupExpr;
 447                         if (mg == null) {
 448                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 449                                 return null;
 450                         }
 451
 452                         return mg;
 453                 }
 454
 455                 /// <summary>
 456                 ///  Verifies whether the method in question is compatible with the delegate
 457                 ///  Returns the method itself if okay and null if not.
 458                 /// </summary>
 459                 public static MethodBase VerifyMethod (EmitContext ec, Type delegate_type, MethodBase mb,
 460                                                        Location loc)
 461                 {
 462                         MethodGroupExpr mg = GetInvokeMethod (ec, delegate_type, loc);
 463                         if (mg == null)
 464                                 return null;
 465
 466                         MethodBase invoke_mb = mg.Methods [0];
 467                         ParameterData invoke_pd = Invocation.GetParameterData (invoke_mb);
 468
 469                         if (!mg.HasTypeArguments &&
 470                             !TypeManager.InferTypeArguments (ec, invoke_pd, ref mb))
 471                                 return null;
 472
 473                         ParameterData pd = Invocation.GetParameterData (mb);
 474                         int pd_count = pd.Count;
 475
 476                         if (invoke_pd.Count != pd_count)
 477                                 return null;
 478
 479                         for (int i = pd_count; i > 0; ) {
 480                                 i--;
 481
 482                                 Type invoke_pd_type = invoke_pd.ParameterType (i);
 483                                 Type pd_type = pd.ParameterType (i);
 484                                 Parameter.Modifier invoke_pd_type_mod = invoke_pd.ParameterModifier (i);
 485                                 Parameter.Modifier pd_type_mod = pd.ParameterModifier (i);
 486
 487                                 if (invoke_pd_type == pd_type &&
 488                                     invoke_pd_type_mod == pd_type_mod)
 489                                         continue;
 490
 491                                 if (invoke_pd_type.IsSubclassOf (pd_type) &&
 492                                                 invoke_pd_type_mod == pd_type_mod)
 493                                         if (RootContext.Version == LanguageVersion.ISO_1) {
 494                                                 Report.FeatureIsNotStandardized (loc, "contravariance");
 495                                                 return null;
 496                                         } else
 497                                                 continue;
 498
 499                                 return null;
 500                         }
 501
 502                         Type invoke_mb_retval = ((MethodInfo) invoke_mb).ReturnType;
 503                         Type mb_retval = ((MethodInfo) mb).ReturnType;
 504                         if (invoke_mb_retval == mb_retval)
 505                                 return mb;
 506
 507                         if (mb_retval.IsSubclassOf (invoke_mb_retval))
 508                                 if (RootContext.Version == LanguageVersion.ISO_1) {
 509                                         Report.FeatureIsNotStandardized (loc, "covariance");
 510                                         return null;
 511                                 }
 512                                 else
 513                                         return mb;
 514
 515                         return null;
 516                 }
 517
 518                 // <summary>
 519                 //  Verifies whether the invocation arguments are compatible with the
 520                 //  delegate's target method
 521                 // </summary>
 522                 public static bool VerifyApplicability (EmitContext ec, Type delegate_type,
 523                                                         ArrayList args, Location loc)
 524                 {
 525                         int arg_count;
 526
 527                         if (args == null)
 528                                 arg_count = 0;
 529                         else
 530                                 arg_count = args.Count;
 531
 532                         Expression ml = Expression.MemberLookup (
 533                                 ec, delegate_type, "Invoke", loc);
 534
 535                         if (!(ml is MethodGroupExpr)) {
 536                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!" + delegate_type);
 537                                 return false;
 538                         }
 539
 540                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 541                         ParameterData pd = Invocation.GetParameterData (mb);
 542
 543                         int pd_count = pd.Count;
 544
 545                         bool params_method = (pd_count != 0) &&
 546                                 (pd.ParameterModifier (pd_count - 1) == Parameter.Modifier.PARAMS);
 547
 548                         if (!params_method && pd_count != arg_count) {
 549                                 Report.Error (1593, loc,
 550                                               "Delegate '{0}' does not take {1} arguments",
 551                                               delegate_type.ToString (), arg_count);
 552                                 return false;
 553                         }
 554
 555                         //
 556                         // Consider the case:
 557                         //   delegate void FOO(param object[] args);
 558                         //   FOO f = new FOO(...);
 559                         //   f(new object[] {1, 2, 3});
 560                         //
 561                         // This should be treated like f(1,2,3).  This is done by ignoring the
 562                         // 'param' modifier for that invocation.  If that fails, then the
 563                         // 'param' modifier is considered.
 564                         //
 565                         // One issue is that 'VerifyArgumentsCompat' modifies the elements of
 566                         // the 'args' array.  However, the modifications appear idempotent.
 567                         // Normal 'Invocation's also have the same behaviour, implicitly.
 568                         //
 569
 570                         bool ans = false;
 571                         if (arg_count == pd_count)
 572                                 ans = Invocation.VerifyArgumentsCompat (
 573                                         ec, args, arg_count, mb, false,
 574                                         delegate_type, false, loc);
 575                         if (!ans && params_method)
 576                                 ans = Invocation.VerifyArgumentsCompat (
 577                                         ec, args, arg_count, mb, true,
 578                                         delegate_type, false, loc);
 579                         return ans;
 580                 }
 581
 582                 /// <summary>
 583                 ///  Verifies whether the delegate in question is compatible with this one in
 584                 ///  order to determine if instantiation from the same is possible.
 585                 /// </summary>
 586                 public static bool VerifyDelegate (EmitContext ec, Type delegate_type, Type probe_type, Location loc)
 587                 {
 588                         Expression ml = Expression.MemberLookup (
 589                                 ec, delegate_type, "Invoke", loc);
 590
 591                         if (!(ml is MethodGroupExpr)) {
 592                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 593                                 return false;
 594                         }
 595
 596                         MethodBase mb = ((MethodGroupExpr) ml).Methods [0];
 597                         ParameterData pd = Invocation.GetParameterData (mb);
 598
 599                         Expression probe_ml = Expression.MemberLookup (
 600                                 ec, delegate_type, "Invoke", loc);
 601
 602                         if (!(probe_ml is MethodGroupExpr)) {
 603                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
 604                                 return false;
 605                         }
 606
 607                         MethodBase probe_mb = ((MethodGroupExpr) probe_ml).Methods [0];
 608                         ParameterData probe_pd = Invocation.GetParameterData (probe_mb);
 609
 610                         if (((MethodInfo) mb).ReturnType != ((MethodInfo) probe_mb).ReturnType)
 611                                 return false;
 612
 613                         if (pd.Count != probe_pd.Count)
 614                                 return false;
 615
 616                         for (int i = pd.Count; i > 0; ) {
 617                                 i--;
 618
 619                                 if (pd.ParameterType (i) != probe_pd.ParameterType (i) ||
 620                                     pd.ParameterModifier (i) != probe_pd.ParameterModifier (i))
 621                                         return false;
 622                         }
 623
 624                         return true;
 625                 }
 626
 627                 public static string FullDelegateDesc (Type del_type, MethodBase mb, ParameterData pd)
 628                 {
 629                         StringBuilder sb = new StringBuilder (TypeManager.CSharpName (((MethodInfo) mb).ReturnType));
 630
 631                         sb.Append (" " + del_type.ToString ());
 632                         sb.Append (" (");
 633
 634                         int length = pd.Count;
 635
 636                         for (int i = length; i > 0; ) {
 637                                 i--;
 638
 639                                 sb.Append (pd.ParameterDesc (length - i - 1));
 640                                 if (i != 0)
 641                                         sb.Append (", ");
 642                         }
 643
 644                         sb.Append (")");
 645                         return sb.ToString ();
 646
 647                 }
 648
 649                 // Hack around System.Reflection as found everywhere else
 650                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 651                                                         MemberFilter filter, object criteria)
 652                 {
 653                         ArrayList members = new ArrayList ();
 654
 655                         if ((mt & MemberTypes.Method) != 0) {
 656                                 if (ConstructorBuilder != null)
 657                                 if (filter (ConstructorBuilder, criteria))
 658                                         members.Add (ConstructorBuilder);
 659
 660                                 if (InvokeBuilder != null)
 661                                 if (filter (InvokeBuilder, criteria))
 662                                         members.Add (InvokeBuilder);
 663
 664                                 if (BeginInvokeBuilder != null)
 665                                 if (filter (BeginInvokeBuilder, criteria))
 666                                         members.Add (BeginInvokeBuilder);
 667
 668                                 if (EndInvokeBuilder != null)
 669                                 if (filter (EndInvokeBuilder, criteria))
 670                                         members.Add (EndInvokeBuilder);
 671                         }
 672
 673                         return new MemberList (members);
 674                 }
 675
 676                 public override MemberCache MemberCache {
 677                         get {
 678                                 return null;
 679                         }
 680                 }
 681
 682                 public Expression InstanceExpression {
 683                         get {
 684                                 return instance_expr;
 685                         }
 686                         set {
 687                                 instance_expr = value;
 688                         }
 689                 }
 690
 691                 public MethodBase TargetMethod {
 692                         get {
 693                                 return delegate_method;
 694                         }
 695                         set {
 696                                 delegate_method = value;
 697                         }
 698                 }
 699
 700                 public Type TargetReturnType {
 701                         get {
 702                                 return ret_type;
 703                         }
 704                 }
 705
 706                 public Type [] ParameterTypes {
 707                         get {
 708                                 return param_types;
 709                         }
 710                 }
 711
 712                 public override AttributeTargets AttributeTargets {
 713                         get {
 714                                 return AttributeTargets.Delegate;
 715                         }
 716                 }
 717
 718                 //
 719                 //   Represents header string for documentation comment.
 720                 //
 721                 public override string DocCommentHeader {
 722                         get { return "T:"; }
 723                 }
 724
 725                 protected override void VerifyObsoleteAttribute()
 726                 {
 727                         CheckUsageOfObsoleteAttribute (ret_type);
 728
 729                         foreach (Type type in param_types) {
 730                                 CheckUsageOfObsoleteAttribute (type);
 731                         }
 732                 }
 733         }
 734
 735         //
 736         // Base class for `NewDelegate' and `ImplicitDelegateCreation'
 737         //
 738         public abstract class DelegateCreation : Expression {
 739                 protected MethodBase constructor_method;
 740                 protected MethodBase delegate_method;
 741                 protected MethodGroupExpr method_group;
 742                 protected Expression delegate_instance_expression;
 743
 744                 public DelegateCreation () {}
 745
 746                 public static void Error_NoMatchingMethodForDelegate (EmitContext ec, MethodGroupExpr mg, Type type, Location loc)
 747                 {
 748                         string method_desc;
 749
 750                         MethodBase candidate = mg.Methods [0];
 751                         if (mg.Methods.Length > 1)
 752                                 method_desc = candidate.Name;
 753                         else
 754                                 method_desc = Invocation.FullMethodDesc (candidate);
 755
 756                         Expression invoke_method = Expression.MemberLookup (
 757                                 ec, type, "Invoke", MemberTypes.Method,
 758                                 Expression.AllBindingFlags, loc);
 759                         MethodBase method = ((MethodGroupExpr) invoke_method).Methods [0];
 760                         ParameterData param = Invocation.GetParameterData (method);
 761                         string delegate_desc = Delegate.FullDelegateDesc (type, method, param);
 762
 763                         if (!mg.HasTypeArguments &&
 764                             !TypeManager.InferTypeArguments (ec, param, ref candidate))
 765                                 Report.Error (411, loc, "The type arguments for " +
 766                                               "method `{0}' cannot be infered from " +
 767                                               "the usage. Try specifying the type " +
 768                                               "arguments explicitly.", method_desc);
 769                         else
 770                                 Report.Error (123, loc, "Method '{0}' does not " +
 771                                               "match delegate '{1}'", method_desc,
 772                                               delegate_desc);
 773                 }
 774
 775                 public override void Emit (EmitContext ec)
 776                 {
 777                         if (delegate_instance_expression == null || delegate_method.IsStatic)
 778                                 ec.ig.Emit (OpCodes.Ldnull);
 779                         else
 780                                 delegate_instance_expression.Emit (ec);
 781
 782                         if (delegate_method.IsVirtual && !method_group.IsBase) {
 783                                 ec.ig.Emit (OpCodes.Dup);
 784                                 ec.ig.Emit (OpCodes.Ldvirtftn, (MethodInfo) delegate_method);
 785                         } else
 786                                 ec.ig.Emit (OpCodes.Ldftn, (MethodInfo) delegate_method);
 787                         ec.ig.Emit (OpCodes.Newobj, (ConstructorInfo) constructor_method);
 788                 }
 789
 790                 protected bool ResolveConstructorMethod (EmitContext ec)
 791                 {
 792                         Expression ml = Expression.MemberLookup (
 793                                 ec, type, ".ctor", loc);
 794
 795                         if (!(ml is MethodGroupExpr)) {
 796                                 Report.Error (-100, loc, "Internal error: Could not find delegate constructor!");
 797                                 return false;
 798                         }
 799
 800                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 801                         return true;
 802                 }
 803
 804                 protected Expression ResolveMethodGroupExpr (EmitContext ec, MethodGroupExpr mg)
 805                 {
 806                                 foreach (MethodInfo mi in mg.Methods){
 807                                         delegate_method = Delegate.VerifyMethod (
 808                                                 ec, type, mi, loc);
 809
 810                                         if (delegate_method != null)
 811                                                 break;
 812                                 }
 813
 814                                 if (delegate_method == null) {
 815                                         Error_NoMatchingMethodForDelegate (ec, mg, type, loc);
 816                                         return null;
 817                                 }
 818
 819                                 //
 820                                 // Check safe/unsafe of the delegate
 821                                 //
 822                                 if (!ec.InUnsafe){
 823                                         ParameterData param = Invocation.GetParameterData (delegate_method);
 824                                         int count = param.Count;
 825
 826                                         for (int i = 0; i < count; i++){
 827                                                 if (param.ParameterType (i).IsPointer){
 828                                                         Expression.UnsafeError (loc);
 829                                                         return null;
 830                                                 }
 831                                         }
 832                                 }
 833
 834                         //TODO: implement caching when performance will be low
 835                         IMethodData md = TypeManager.GetMethod (delegate_method);
 836                         if (md == null) {
 837                                 if (System.Attribute.GetCustomAttribute (delegate_method, TypeManager.conditional_attribute_type) != null) {
 838                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 839                                 }
 840                         } else {
 841                                 if (md.OptAttributes != null && md.OptAttributes.Search (TypeManager.conditional_attribute_type, ec) != null) {
 842                                         Report.Error (1618, loc, "Cannot create delegate with '{0}' because it has a Conditional attribute", TypeManager.CSharpSignature (delegate_method));
 843                                 }
 844                         }
 845
 846                         if (mg.InstanceExpression != null)
 847                                 delegate_instance_expression = mg.InstanceExpression.Resolve (ec);
 848                         else if (ec.IsStatic) {
 849                                 if (!delegate_method.IsStatic) {
 850                                         Report.Error (120, loc,
 851                                                       "An object reference is required for the non-static method " +
 852                                                       delegate_method.Name);
 853                                         return null;
 854                                 }
 855                                 delegate_instance_expression = null;
 856                         } else
 857                                 delegate_instance_expression = ec.GetThis (loc);
 858
 859                         if (delegate_instance_expression != null && delegate_instance_expression.Type.IsValueType)
 860                                 delegate_instance_expression = new BoxedCast (delegate_instance_expression);
 861
 862                         method_group = mg;
 863                         eclass = ExprClass.Value;
 864                         return this;
 865                 }
 866         }
 867
 868         //
 869         // Created from the conversion code
 870         //
 871         public class ImplicitDelegateCreation : DelegateCreation {
 872
 873                 ImplicitDelegateCreation (Type t, Location l)
 874                 {
 875                         type = t;
 876                         loc = l;
 877                 }
 878
 879                 public override Expression DoResolve (EmitContext ec)
 880                 {
 881                         return this;
 882                 }
 883
 884                 static public Expression Create (EmitContext ec, MethodGroupExpr mge, Type target_type, Location loc)
 885                 {
 886                         ImplicitDelegateCreation d = new ImplicitDelegateCreation (target_type, loc);
 887                         if (d.ResolveConstructorMethod (ec))
 888                                 return d.ResolveMethodGroupExpr (ec, mge);
 889                         else
 890                                 return null;
 891                 }
 892         }
 893
 894         //
 895         // A delegate-creation-expression, invoked from the `New' class
 896         //
 897         public class NewDelegate : DelegateCreation {
 898                 public ArrayList Arguments;
 899
 900                 //
 901                 // This constructor is invoked from the `New' expression
 902                 //
 903                 public NewDelegate (Type type, ArrayList Arguments, Location loc)
 904                 {
 905                         this.type = type;
 906                         this.Arguments = Arguments;
 907                         this.loc  = loc;
 908                 }
 909
 910                 public override Expression DoResolve (EmitContext ec)
 911                 {
 912                         if (Arguments == null || Arguments.Count != 1) {
 913                                 Report.Error (149, loc,
 914                                               "Method name expected");
 915                                 return null;
 916                         }
 917
 918                         if (!ResolveConstructorMethod (ec))
 919                                 return null;
 920
 921                         Argument a = (Argument) Arguments [0];
 922
 923                         if (!a.ResolveMethodGroup (ec, loc))
 924                                 return null;
 925
 926                         Expression e = a.Expr;
 927
 928                         if (e is AnonymousMethod && RootContext.Version != LanguageVersion.ISO_1)
 929                                 return ((AnonymousMethod) e).Compatible (ec, type, false);
 930
 931                         MethodGroupExpr mg = e as MethodGroupExpr;
 932                         if (mg != null)
 933                                 return ResolveMethodGroupExpr (ec, mg);
 934
 935                         Type e_type = e.Type;
 936
 937                         if (!TypeManager.IsDelegateType (e_type)) {
 938                                 Report.Error (149, loc, "Method name expected");
 939                                 return null;
 940                         }
 941
 942                         method_group = Expression.MemberLookup (
 943                                 ec, type, "Invoke", MemberTypes.Method,
 944                                 Expression.AllBindingFlags, loc) as MethodGroupExpr;
 945
 946                         if (method_group == null) {
 947                                 Report.Error (-200, loc, "Internal error ! Could not find Invoke method!");
 948                                 return null;
 949                         }
 950
 951                         // This is what MS' compiler reports. We could always choose
 952                         // to be more verbose and actually give delegate-level specifics
 953                         if (!Delegate.VerifyDelegate (ec, type, e_type, loc)) {
 954                                 Report.Error (29, loc, "Cannot implicitly convert type '" + e_type + "' " +
 955                                               "to type '" + type + "'");
 956                                 return null;
 957                         }
 958
 959                         delegate_instance_expression = e;
 960                         delegate_method = method_group.Methods [0];
 961
 962                         eclass = ExprClass.Value;
 963                         return this;
 964                 }
 965         }
 966
 967         public class DelegateInvocation : ExpressionStatement {
 968
 969                 public Expression InstanceExpr;
 970                 public ArrayList  Arguments;
 971
 972                 MethodBase method;
 973
 974                 public DelegateInvocation (Expression instance_expr, ArrayList args, Location loc)
 975                 {
 976                         this.InstanceExpr = instance_expr;
 977                         this.Arguments = args;
 978                         this.loc = loc;
 979                 }
 980
 981                 public override Expression DoResolve (EmitContext ec)
 982                 {
 983                         if (InstanceExpr is EventExpr) {
 984
 985                                 EventInfo ei = ((EventExpr) InstanceExpr).EventInfo;
 986
 987                                 Expression ml = MemberLookup (
 988                                         ec, ec.ContainerType, ei.Name,
 989                                         MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
 990
 991                                 if (ml == null) {
 992                                         //
 993                                         // If this is the case, then the Event does not belong
 994                                         // to this Type and so, according to the spec
 995                                         // cannot be accessed directly
 996                                         //
 997                                         // Note that target will not appear as an EventExpr
 998                                         // in the case it is being referenced within the same type container;
 999                                         // it will appear as a FieldExpr in that case.
1000                                         //
1001
1002                                         Assign.error70 (ei, loc);
1003                                         return null;
1004                                 }
1005                         }
1006
1007
1008                         Type del_type = InstanceExpr.Type;
1009                         if (del_type == null)
1010                                 return null;
1011
1012                         if (Arguments != null){
1013                                 foreach (Argument a in Arguments){
1014                                         if (!a.Resolve (ec, loc))
1015                                                 return null;
1016                                 }
1017                         }
1018
1019                         if (!Delegate.VerifyApplicability (ec, del_type, Arguments, loc))
1020                                 return null;
1021
1022                         Expression lookup = Expression.MemberLookup (ec, del_type, "Invoke", loc);
1023                         if (!(lookup is MethodGroupExpr)) {
1024                                 Report.Error (-100, loc, "Internal error: could not find Invoke method!");
1025                                 return null;
1026                         }
1027
1028                         method = ((MethodGroupExpr) lookup).Methods [0];
1029                         type = ((MethodInfo) method).ReturnType;
1030                         eclass = ExprClass.Value;
1031
1032                         return this;
1033                 }
1034
1035                 public override void Emit (EmitContext ec)
1036                 {
1037                         //
1038                         // Invocation on delegates call the virtual Invoke member
1039                         // so we are always `instance' calls
1040                         //
1041                         Invocation.EmitCall (ec, false, false, InstanceExpr, method, Arguments, loc);
1042                 }
1043
1044                 public override void EmitStatement (EmitContext ec)
1045                 {
1046                         Emit (ec);
1047                         //
1048                         // Pop the return value if there is one
1049                         //
1050                         if (method is MethodInfo){
1051                                 if (((MethodInfo) method).ReturnType != TypeManager.void_type)
1052                                         ec.ig.Emit (OpCodes.Pop);
1053                         }
1054                 }
1055
1056         }
1057 }