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