mcs/mbas/attribute.cs

   1 //
   2 // attribute.cs: Attribute Handler
   3 //
   4 // Author: Ravi Pratap (ravi@ximian.com)
   5 //
   6 // Licensed under the terms of the GNU GPL
   7 //
   8 // (C) 2001 Ximian, Inc (http://www.ximian.com)
   9 //
  10 //
  11
  12 using System;
  13 using System.Diagnostics;
  14 using System.Collections;
  15 using System.Reflection;
  16 using System.Reflection.Emit;
  17 using System.Runtime.InteropServices;
  18 using System.Runtime.CompilerServices;
  19 using System.Text;
  20
  21 namespace Mono.CSharp {
  22
  23         public class Attribute {
  24                 public readonly string    Name;
  25                 public readonly ArrayList Arguments;
  26
  27                 Location Location;
  28
  29                 public Type Type;
  30
  31                 //
  32                 // The following are only meaningful when the attribute
  33                 // being emitted is one of the builtin ones
  34                 //
  35                 AttributeTargets Targets;
  36                 bool AllowMultiple;
  37                 bool Inherited;
  38
  39                 bool UsageAttr = false;
  40
  41                 MethodImplOptions ImplOptions;
  42                 UnmanagedType     UnmanagedType;
  43                 CustomAttributeBuilder cb;
  44
  45                 public Attribute (string name, ArrayList args, Location loc)
  46                 {
  47                         Name = name;
  48                         Arguments = args;
  49                         Location = loc;
  50                 }
  51
  52                 void Error_InvalidNamedArgument (string name)
  53                 {
  54                         Report.Error (617, Location, "'" + name + "' is not a valid named attribute " +
  55                                       "argument. Named attribute arguments must be fields which are not " +
  56                                       "readonly, static or const, or properties with a set accessor which "+
  57                                       "are not static.");
  58                 }
  59
  60                 void Error_AttributeArgumentNotValid ()
  61                 {
  62                         Report.Error (182, Location,
  63                                       "An attribute argument must be a constant expression, typeof " +
  64                                       "expression or array creation expression");
  65                 }
  66
  67                 static void Error_AttributeConstructorMismatch (Location loc)
  68                 {
  69                         Report.Error (
  70                                         -6, loc,
  71                                         "Could not find a constructor for this argument list.");
  72                 }
  73
  74                 private Type CheckAttributeType (EmitContext ec) {
  75                         Type t;
  76                         bool isattributeclass = true;
  77
  78                         t = RootContext.LookupType (ec.DeclSpace, Name, true, Location);
  79                         if (t != null) {
  80                                 isattributeclass = t.IsSubclassOf (TypeManager.attribute_type);
  81                                 if (isattributeclass)
  82                                         return t;
  83                         }
  84                         t = RootContext.LookupType (ec.DeclSpace, Name + "Attribute", true, Location);
  85                         if (t != null) {
  86                                 if (t.IsSubclassOf (TypeManager.attribute_type))
  87                                         return t;
  88                         }
  89                         if (!isattributeclass) {
  90                                 Report.Error (616, Location, "'" + Name + "': is not an attribute class");
  91                                 return null;
  92                         }
  93                         if (t != null) {
  94                                 Report.Error (616, Location, "'" + Name + "Attribute': is not an attribute class");
  95                                 return null;
  96                         }
  97                         Report.Error (
  98                                 246, Location, "Could not find attribute '" + Name + "' (are you" +
  99                                 " missing a using directive or an assembly reference ?)");
 100                         return null;
 101                 }
 102
 103                 public Type ResolveType (EmitContext ec)
 104                 {
 105                         Type = CheckAttributeType (ec);
 106                         return Type;
 107                 }
 108
 109
 110                 public CustomAttributeBuilder Resolve (EmitContext ec)
 111                 {
 112                         if (Type == null)
 113                                 Type = CheckAttributeType (ec);
 114                         if (Type == null)
 115                                 return null;
 116
 117                         bool MethodImplAttr = false;
 118                         bool MarshalAsAttr = false;
 119
 120                         UsageAttr = false;
 121
 122                         if (Type == TypeManager.attribute_usage_type)
 123                                 UsageAttr = true;
 124                         if (Type == TypeManager.methodimpl_attr_type)
 125                                 MethodImplAttr = true;
 126                         if (Type == TypeManager.marshal_as_attr_type)
 127                                 MarshalAsAttr = true;
 128
 129                         // Now we extract the positional and named arguments
 130
 131                         ArrayList pos_args = new ArrayList ();
 132                         ArrayList named_args = new ArrayList ();
 133                         int pos_arg_count = 0;
 134
 135                         if (Arguments != null) {
 136                                 pos_args = (ArrayList) Arguments [0];
 137                                 if (pos_args != null)
 138                                         pos_arg_count = pos_args.Count;
 139                                 if (Arguments.Count > 1)
 140                                         named_args = (ArrayList) Arguments [1];
 141                         }
 142
 143                         object [] pos_values = new object [pos_arg_count];
 144
 145                         //
 146                         // First process positional arguments
 147                         //
 148
 149                         int i;
 150                         for (i = 0; i < pos_arg_count; i++) {
 151                                 Argument a = (Argument) pos_args [i];
 152                                 Expression e;
 153
 154                                 if (!a.Resolve (ec, Location))
 155                                         return null;
 156
 157                                 e = a.Expr;
 158                                 if (e is Constant) {
 159                                         pos_values [i] = ((Constant) e).GetValue ();
 160                                 } else if (e is TypeOf) {
 161                                         pos_values [i] = ((TypeOf) e).TypeArg;
 162                                 } else {
 163                                         Error_AttributeArgumentNotValid ();
 164                                         return null;
 165                                 }
 166
 167                                 if (UsageAttr)
 168                                         this.Targets = (AttributeTargets) pos_values [0];
 169
 170                                 if (MethodImplAttr)
 171                                         this.ImplOptions = (MethodImplOptions) pos_values [0];
 172
 173                                 if (MarshalAsAttr)
 174                                         this.UnmanagedType =
 175                                         (System.Runtime.InteropServices.UnmanagedType) pos_values [0];
 176                         }
 177
 178                         //
 179                         // Now process named arguments
 180                         //
 181
 182                         ArrayList field_infos = new ArrayList ();
 183                         ArrayList prop_infos  = new ArrayList ();
 184                         ArrayList field_values = new ArrayList ();
 185                         ArrayList prop_values = new ArrayList ();
 186
 187                         for (i = 0; i < named_args.Count; i++) {
 188                                 DictionaryEntry de = (DictionaryEntry) named_args [i];
 189                                 string member_name = (string) de.Key;
 190                                 Argument a  = (Argument) de.Value;
 191                                 Expression e;
 192
 193                                 if (!a.Resolve (ec, Location))
 194                                         return null;
 195
 196                                 Expression member = Expression.MemberLookup (
 197                                         ec, Type, member_name,
 198                                         MemberTypes.Field | MemberTypes.Property,
 199                                         BindingFlags.Public | BindingFlags.Instance,
 200                                         Location);
 201
 202                                 if (member == null || !(member is PropertyExpr || member is FieldExpr)) {
 203                                         Error_InvalidNamedArgument (member_name);
 204                                         return null;
 205                                 }
 206
 207                                 e = a.Expr;
 208                                 if (member is PropertyExpr) {
 209                                         PropertyExpr pe = (PropertyExpr) member;
 210                                         PropertyInfo pi = pe.PropertyInfo;
 211
 212                                         if (!pi.CanWrite) {
 213                                                 Error_InvalidNamedArgument (member_name);
 214                                                 return null;
 215                                         }
 216
 217                                         if (e is Constant) {
 218                                                 object o = ((Constant) e).GetValue ();
 219                                                 prop_values.Add (o);
 220
 221                                                 if (UsageAttr) {
 222                                                         if (member_name == "AllowMultiple")
 223                                                                 this.AllowMultiple = (bool) o;
 224                                                         if (member_name == "Inherited")
 225                                                                 this.Inherited = (bool) o;
 226                                                 }
 227
 228                                         } else {
 229                                                 Error_AttributeArgumentNotValid ();
 230                                                 return null;
 231                                         }
 232
 233                                         prop_infos.Add (pi);
 234
 235                                 } else if (member is FieldExpr) {
 236                                         FieldExpr fe = (FieldExpr) member;
 237                                         FieldInfo fi = fe.FieldInfo;
 238
 239                                         if (fi.IsInitOnly) {
 240                                                 Error_InvalidNamedArgument (member_name);
 241                                                 return null;
 242                                         }
 243
 244                                         //
 245                                         // Handle charset here, and set the TypeAttributes
 246
 247                                         if (e is Constant){
 248                                                 object value = ((Constant) e).GetValue ();
 249
 250                                                 field_values.Add (value);
 251                                         } else {
 252                                                 Error_AttributeArgumentNotValid ();
 253                                                 return null;
 254                                         }
 255
 256                                         field_infos.Add (fi);
 257                                 }
 258                         }
 259
 260                         Expression mg = Expression.MemberLookup (
 261                                 ec, Type, ".ctor", MemberTypes.Constructor,
 262                                 BindingFlags.Public | BindingFlags.Instance, Location);
 263
 264                         if (mg == null) {
 265                                 Error_AttributeConstructorMismatch (Location);
 266                                 return null;
 267                         }
 268
 269                         MethodBase constructor = Invocation.OverloadResolve (
 270                                 ec, (MethodGroupExpr) mg, pos_args, Location);
 271
 272                         if (constructor == null) {
 273                                 Error_AttributeConstructorMismatch (Location);
 274                                 return null;
 275                         }
 276
 277                         PropertyInfo [] prop_info_arr = new PropertyInfo [prop_infos.Count];
 278                         FieldInfo [] field_info_arr = new FieldInfo [field_infos.Count];
 279                         object [] field_values_arr = new object [field_values.Count];
 280                         object [] prop_values_arr = new object [prop_values.Count];
 281
 282                         field_infos.CopyTo  (field_info_arr, 0);
 283                         field_values.CopyTo (field_values_arr, 0);
 284
 285                         prop_values.CopyTo  (prop_values_arr, 0);
 286                         prop_infos.CopyTo   (prop_info_arr, 0);
 287
 288                         try {
 289                                 cb = new CustomAttributeBuilder (
 290                                         (ConstructorInfo) constructor, pos_values,
 291                                         prop_info_arr, prop_values_arr,
 292                                         field_info_arr, field_values_arr);
 293                         } catch (NullReferenceException) {
 294                                 Report.Warning (
 295                                         -23, Location,
 296                                         "The compiler can not encode this attribute in the Mono runtime\n" +
 297                                         "\tdue to a known bug in it.  We know about the problem and will\n" +
 298                                         "\tfix it as soon as possible.");
 299                         } catch {
 300                                 //
 301                                 // Sample:
 302                                 // using System.ComponentModel;
 303                                 // [DefaultValue (CollectionChangeAction.Add)]
 304                                 // class X { static void Main () {} }
 305                                 //
 306                                 Report.Warning (
 307                                         -23, Location,
 308                                         "The compiler can not encode this attribute in .NET due to\n" +
 309                                         "\ta bug in the .NET runtime.  Try the Mono runtime");
 310                         }
 311
 312                         return cb;
 313                 }
 314
 315                 static string GetValidPlaces (Attribute attr)
 316                 {
 317                         StringBuilder sb = new StringBuilder ();
 318                         AttributeTargets targets = 0;
 319
 320                         TypeContainer a = TypeManager.LookupAttr (attr.Type);
 321
 322                         if (a == null) {
 323
 324                                 System.Attribute [] attrs = null;
 325
 326                                 try {
 327                                         attrs = System.Attribute.GetCustomAttributes (attr.Type);
 328
 329                                 } catch {
 330                                         Report.Error (-20, attr.Location, "Cannot find attribute type " + attr.Name +
 331                                                       " (maybe you forgot to set the usage using the" +
 332                                                       " AttributeUsage attribute ?).");
 333                                         return null;
 334                                 }
 335
 336                                 foreach (System.Attribute tmp in attrs)
 337                                         if (tmp is AttributeUsageAttribute) {
 338                                                 targets = ((AttributeUsageAttribute) tmp).ValidOn;
 339                                                 break;
 340                                         }
 341                         } else
 342                                 targets = a.Targets;
 343
 344
 345                         if ((targets & AttributeTargets.Assembly) != 0)
 346                                 sb.Append ("'assembly' ");
 347
 348                         if ((targets & AttributeTargets.Class) != 0)
 349                                 sb.Append ("'class' ");
 350
 351                         if ((targets & AttributeTargets.Constructor) != 0)
 352                                 sb.Append ("'constructor' ");
 353
 354                         if ((targets & AttributeTargets.Delegate) != 0)
 355                                 sb.Append ("'delegate' ");
 356
 357                         if ((targets & AttributeTargets.Enum) != 0)
 358                                 sb.Append ("'enum' ");
 359
 360                         if ((targets & AttributeTargets.Event) != 0)
 361                                 sb.Append ("'event' ");
 362
 363                         if ((targets & AttributeTargets.Field) != 0)
 364                                 sb.Append ("'field' ");
 365
 366                         if ((targets & AttributeTargets.Interface) != 0)
 367                                 sb.Append ("'interface' ");
 368
 369                         if ((targets & AttributeTargets.Method) != 0)
 370                                 sb.Append ("'method' ");
 371
 372                         if ((targets & AttributeTargets.Module) != 0)
 373                                 sb.Append ("'module' ");
 374
 375                         if ((targets & AttributeTargets.Parameter) != 0)
 376                                 sb.Append ("'parameter' ");
 377
 378                         if ((targets & AttributeTargets.Property) != 0)
 379                                 sb.Append ("'property' ");
 380
 381                         if ((targets & AttributeTargets.ReturnValue) != 0)
 382                                 sb.Append ("'return value' ");
 383
 384                         if ((targets & AttributeTargets.Struct) != 0)
 385                                 sb.Append ("'struct' ");
 386
 387                         return sb.ToString ();
 388
 389                 }
 390
 391                 public static void Error_AttributeNotValidForElement (Attribute a, Location loc)
 392                 {
 393                         Report.Error (
 394                                 592, loc, "Attribute '" + a.Name +
 395                                 "' is not valid on this declaration type. " +
 396                                 "It is valid on " + GetValidPlaces (a) + "declarations only.");
 397                 }
 398
 399                 public static bool CheckAttribute (Attribute a, object element)
 400                 {
 401                         TypeContainer attr = TypeManager.LookupAttr (a.Type);
 402                         AttributeTargets targets = 0;
 403
 404
 405                         if (attr == null) {
 406
 407                                 System.Attribute [] attrs = null;
 408
 409                                 try {
 410                                         attrs = System.Attribute.GetCustomAttributes (a.Type);
 411
 412                                 } catch {
 413                                         Report.Error (-20, a.Location, "Cannot find attribute type " + a.Name +
 414                                                       " (maybe you forgot to set the usage using the" +
 415                                                       " AttributeUsage attribute ?).");
 416                                         return false;
 417                                 }
 418
 419                                 foreach (System.Attribute tmp in attrs)
 420                                         if (tmp is AttributeUsageAttribute)
 421                                                 targets = ((AttributeUsageAttribute) tmp).ValidOn;
 422                         } else
 423                                 targets = attr.Targets;
 424
 425                         if (element is Class) {
 426                                 if ((targets & AttributeTargets.Class) != 0)
 427                                         return true;
 428                                 else
 429                                         return false;
 430
 431                         } else if (element is Struct) {
 432                                 if ((targets & AttributeTargets.Struct) != 0)
 433                                         return true;
 434                                 else
 435                                         return false;
 436                         } else if (element is Constructor) {
 437                                 if ((targets & AttributeTargets.Constructor) != 0)
 438                                         return true;
 439                                 else
 440                                         return false;
 441                         } else if (element is Delegate) {
 442                                 if ((targets & AttributeTargets.Delegate) != 0)
 443                                         return true;
 444                                 else
 445                                         return false;
 446                         } else if (element is Enum) {
 447                                 if ((targets & AttributeTargets.Enum) != 0)
 448                                         return true;
 449                                 else
 450                                         return false;
 451                         } else if (element is Event || element is InterfaceEvent) {
 452                                 if ((targets & AttributeTargets.Event) != 0)
 453                                         return true;
 454                                 else
 455                                         return false;
 456                         } else if (element is Field || element is FieldBuilder) {
 457                                 if ((targets & AttributeTargets.Field) != 0)
 458                                         return true;
 459                                 else
 460                                         return false;
 461                         } else if (element is Interface) {
 462                                 if ((targets & AttributeTargets.Interface) != 0)
 463                                         return true;
 464                                 else
 465                                         return false;
 466                         } else if (element is Method || element is Operator || element is InterfaceMethod || element is Accessor) {
 467                                 if ((targets & AttributeTargets.Method) != 0)
 468                                         return true;
 469                                 else
 470                                         return false;
 471                         } else if (element is ParameterBuilder) {
 472                                 if ((targets & AttributeTargets.Parameter) != 0)
 473                                         return true;
 474                                 else
 475                                         return false;
 476                         } else if (element is Property || element is Indexer ||
 477                                    element is InterfaceProperty || element is InterfaceIndexer) {
 478                                 if ((targets & AttributeTargets.Property) != 0)
 479                                         return true;
 480                                 else
 481                                         return false;
 482                         } else if (element is AssemblyBuilder){
 483                                 if ((targets & AttributeTargets.Assembly) != 0)
 484                                         return true;
 485                                 else
 486                                         return false;
 487                         }
 488
 489                         return false;
 490                 }
 491
 492                 //
 493                 // This method should be invoked to pull the IndexerName attribute from an
 494                 // Indexer if it exists.
 495                 //
 496                 public static string ScanForIndexerName (EmitContext ec, Attributes opt_attrs)
 497                 {
 498                         if (opt_attrs == null)
 499                                 return null;
 500                         if (opt_attrs.AttributeSections == null)
 501                                 return null;
 502
 503                         foreach (AttributeSection asec in opt_attrs.AttributeSections) {
 504                                 if (asec.Attributes == null)
 505                                         continue;
 506
 507                                 foreach (Attribute a in asec.Attributes){
 508                                         if (a.ResolveType (ec) == null)
 509                                                 return null;
 510
 511                                         if (a.Type != TypeManager.indexer_name_type)
 512                                                 continue;
 513
 514                                         //
 515                                         // So we have found an IndexerName, pull the data out.
 516                                         //
 517                                         if (a.Arguments == null || a.Arguments [0] == null){
 518                                                 Error_AttributeConstructorMismatch (a.Location);
 519                                                 return null;
 520                                         }
 521                                         ArrayList pos_args = (ArrayList) a.Arguments [0];
 522                                         if (pos_args.Count == 0){
 523                                                 Error_AttributeConstructorMismatch (a.Location);
 524                                                 return null;
 525                                         }
 526
 527                                         Argument arg = (Argument) pos_args [0];
 528                                         if (!arg.Resolve (ec, a.Location))
 529                                                 return null;
 530
 531                                         Expression e = arg.Expr;
 532                                         if (!(e is StringConstant)){
 533                                                 Error_AttributeConstructorMismatch (a.Location);
 534                                                 return null;
 535                                         }
 536
 537                                         //
 538                                         // Remove the attribute from the list
 539                                         //
 540                                         asec.Attributes.Remove (a);
 541
 542                                         return (((StringConstant) e).Value);
 543                                 }
 544                         }
 545                         return null;
 546                 }
 547
 548                 //
 549                 // This pulls the condition name out of a Conditional attribute
 550                 //
 551                 public string Conditional_GetConditionName ()
 552                 {
 553                         //
 554                         // So we have a Conditional, pull the data out.
 555                         //
 556                         if (Arguments == null || Arguments [0] == null){
 557                                 Error_AttributeConstructorMismatch (Location);
 558                                 return null;
 559                         }
 560
 561                         ArrayList pos_args = (ArrayList) Arguments [0];
 562                         if (pos_args.Count != 1){
 563                                 Error_AttributeConstructorMismatch (Location);
 564                                 return null;
 565                         }
 566
 567                         Argument arg = (Argument) pos_args [0];
 568                         if (!(arg.Expr is StringConstant)){
 569                                 Error_AttributeConstructorMismatch (Location);
 570                                 return null;
 571                         }
 572
 573                         return ((StringConstant) arg.Expr).Value;
 574                 }
 575
 576                 //
 577                 // This pulls the obsolete message and error flag out of an Obsolete attribute
 578                 //
 579                 public string Obsolete_GetObsoleteMessage (out bool is_error)
 580                 {
 581                         is_error = false;
 582                         //
 583                         // So we have an Obsolete, pull the data out.
 584                         //
 585                         if (Arguments == null || Arguments [0] == null)
 586                                 return "";
 587
 588                         ArrayList pos_args = (ArrayList) Arguments [0];
 589                         if (pos_args.Count == 0)
 590                                 return "";
 591                         else if (pos_args.Count > 2){
 592                                 Error_AttributeConstructorMismatch (Location);
 593                                 return null;
 594                         }
 595
 596                         Argument arg = (Argument) pos_args [0];
 597                         if (!(arg.Expr is StringConstant)){
 598                                 Error_AttributeConstructorMismatch (Location);
 599                                 return null;
 600                         }
 601
 602                         if (pos_args.Count == 2){
 603                                 Argument arg2 = (Argument) pos_args [1];
 604                                 if (!(arg2.Expr is BoolConstant)){
 605                                         Error_AttributeConstructorMismatch (Location);
 606                                         return null;
 607                                 }
 608                                 is_error = ((BoolConstant) arg2.Expr).Value;
 609                         }
 610
 611                         return ((StringConstant) arg.Expr).Value;
 612                 }
 613
 614                 //
 615                 // Applies the attributes to the `builder'.
 616                 //
 617                 public static void ApplyAttributes (EmitContext ec, object builder, object kind,
 618                                                     Attributes opt_attrs, Location loc)
 619                 {
 620                         if (opt_attrs == null)
 621                                 return;
 622                         if (opt_attrs.AttributeSections == null)
 623                                 return;
 624
 625                         foreach (AttributeSection asec in opt_attrs.AttributeSections) {
 626                                 if (asec.Attributes == null)
 627                                         continue;
 628
 629                                 if (asec.Target == "assembly" && !(builder is AssemblyBuilder))
 630                                         continue;
 631
 632                                 foreach (Attribute a in asec.Attributes) {
 633                                         CustomAttributeBuilder cb = a.Resolve (ec);
 634
 635                                         if (cb == null)
 636                                                 continue;
 637
 638                                         if (!(kind is TypeContainer))
 639                                                 if (!CheckAttribute (a, kind)) {
 640                                                         Error_AttributeNotValidForElement (a, loc);
 641                                                         return;
 642                                                 }
 643
 644                                         if (kind is Method || kind is Operator || kind is InterfaceMethod ||
 645                                             kind is Accessor) {
 646                                                 if (a.Type == TypeManager.methodimpl_attr_type) {
 647                                                         if (a.ImplOptions == MethodImplOptions.InternalCall)
 648                                                                 ((MethodBuilder) builder).
 649                                                                 SetImplementationFlags (
 650                                                                         MethodImplAttributes.InternalCall |
 651                                                                         MethodImplAttributes.Runtime);
 652                                                 } else if (a.Type != TypeManager.dllimport_type){
 653                                                         ((MethodBuilder) builder).SetCustomAttribute (cb);
 654                                                 }
 655                                         } else if (kind is Constructor) {
 656                                                 ((ConstructorBuilder) builder).SetCustomAttribute (cb);
 657                                         } else if (kind is Field) {
 658                                                 ((FieldBuilder) builder).SetCustomAttribute (cb);
 659                                         } else if (kind is Property || kind is Indexer ||
 660                                                    kind is InterfaceProperty || kind is InterfaceIndexer) {
 661                                                 ((PropertyBuilder) builder).SetCustomAttribute (cb);
 662                                         } else if (kind is Event || kind is InterfaceEvent) {
 663                                                 ((MyEventBuilder) builder).SetCustomAttribute (cb);
 664                                         } else if (kind is ParameterBuilder) {
 665
 666                                                 if (a.Type == TypeManager.marshal_as_attr_type) {
 667                                                         UnmanagedMarshal marshal =
 668                                                                 UnmanagedMarshal.DefineUnmanagedMarshal (a.UnmanagedType);
 669
 670                                                         ((ParameterBuilder) builder).SetMarshal (marshal);
 671                                                 } else
 672                                                         ((ParameterBuilder) builder).SetCustomAttribute (cb);
 673
 674                                         } else if (kind is Enum) {
 675                                                 ((TypeBuilder) builder).SetCustomAttribute (cb);
 676
 677                                         } else if (kind is TypeContainer) {
 678                                                 TypeContainer tc = (TypeContainer) kind;
 679
 680                                                 if (a.UsageAttr) {
 681                                                         tc.Targets = a.Targets;
 682                                                         tc.AllowMultiple = a.AllowMultiple;
 683                                                         tc.Inherited = a.Inherited;
 684
 685                                                 } else if (a.Type == TypeManager.default_member_type) {
 686                                                         if (tc.Indexers != null) {
 687                                                                 Report.Error (646, loc,
 688                                                                       "Cannot specify the DefaultMember attribute on" +
 689                                                                       " a type containing an indexer");
 690                                                                 return;
 691                                                         }
 692
 693                                                 } else {
 694                                                         if (!CheckAttribute (a, kind)) {
 695                                                                 Error_AttributeNotValidForElement (a, loc);
 696                                                                 return;
 697                                                         }
 698                                                 }
 699
 700                                                 try {
 701                                                         ((TypeBuilder) builder).SetCustomAttribute (cb);
 702                                                 } catch (System.ArgumentException) {
 703                                                         Report.Warning (
 704                                                                 -21, loc,
 705                                                 "The CharSet named property on StructLayout\n"+
 706                                                 "\tdoes not work correctly on Microsoft.NET\n"+
 707                                                 "\tYou might want to remove the CharSet declaration\n"+
 708                                                 "\tor compile using the Mono runtime instead of the\n"+
 709                                                 "\tMicrosoft .NET runtime");
 710                                                 }
 711
 712                                         } else if (kind is Interface) {
 713                                                 Interface iface = (Interface) kind;
 714
 715                                                 if ((a.Type == TypeManager.default_member_type) &&
 716                                                     (iface.InterfaceIndexers != null)) {
 717                                                         Report.Error (
 718                                                                 646, loc,
 719                                                                 "Cannot specify the DefaultMember attribute on" +
 720                                                                 " a type containing an indexer");
 721                                                         return;
 722                                                 }
 723
 724                                                 if (!CheckAttribute (a, kind)) {
 725                                                         Error_AttributeNotValidForElement (a, loc);
 726                                                         return;
 727                                                 }
 728
 729                                                 ((TypeBuilder) builder).SetCustomAttribute (cb);
 730                                         } else if (kind is AssemblyBuilder){
 731                                                 ((AssemblyBuilder) builder).SetCustomAttribute (cb);
 732                                         } else if (kind is ModuleBuilder) {
 733                                                 ((ModuleBuilder) builder).SetCustomAttribute (cb);
 734                                         } else if (kind is FieldBuilder) {
 735                                                 ((FieldBuilder) builder).SetCustomAttribute (cb);
 736                                         } else
 737                                                 throw new Exception ("Unknown kind: " + kind);
 738                                 }
 739                         }
 740                 }
 741
 742                 public MethodBuilder DefinePInvokeMethod (EmitContext ec, TypeBuilder builder, string name,
 743                                                           MethodAttributes flags, Type ret_type, Type [] param_types)
 744                 {
 745                         //
 746                         // We extract from the attribute the information we need
 747                         //
 748
 749                         if (Arguments == null) {
 750                                 Console.WriteLine ("Internal error : this is not supposed to happen !");
 751                                 return null;
 752                         }
 753
 754                         Type = CheckAttributeType (ec);
 755                         if (Type == null)
 756                                 return null;
 757
 758                         ArrayList named_args = new ArrayList ();
 759
 760                         ArrayList pos_args = (ArrayList) Arguments [0];
 761                         if (Arguments.Count > 1)
 762                                 named_args = (ArrayList) Arguments [1];
 763
 764
 765                         string dll_name = null;
 766
 767                         Argument tmp = (Argument) pos_args [0];
 768
 769                         if (!tmp.Resolve (ec, Location))
 770                                 return null;
 771
 772                         if (tmp.Expr is Constant)
 773                                 dll_name = (string) ((Constant) tmp.Expr).GetValue ();
 774                         else {
 775                                 Error_AttributeArgumentNotValid ();
 776                                 return null;
 777                         }
 778
 779                         // Now we process the named arguments
 780                         CallingConvention cc = CallingConvention.Winapi;
 781                         CharSet charset = CharSet.Ansi;
 782                         bool preserve_sig = true;
 783                         bool exact_spelling = false;
 784                         bool set_last_err = false;
 785                         string entry_point = null;
 786
 787                         for (int i = 0; i < named_args.Count; i++) {
 788
 789                                 DictionaryEntry de = (DictionaryEntry) named_args [i];
 790
 791                                 string member_name = (string) de.Key;
 792                                 Argument a  = (Argument) de.Value;
 793
 794                                 if (!a.Resolve (ec, Location))
 795                                         return null;
 796
 797                                 Expression member = Expression.MemberLookup (
 798                                         ec, Type, member_name,
 799                                         MemberTypes.Field | MemberTypes.Property,
 800                                         BindingFlags.Public | BindingFlags.Instance,
 801                                         Location);
 802
 803                                 if (member == null || !(member is FieldExpr)) {
 804                                         Error_InvalidNamedArgument (member_name);
 805                                         return null;
 806                                 }
 807
 808                                 if (member is FieldExpr) {
 809                                         FieldExpr fe = (FieldExpr) member;
 810                                         FieldInfo fi = fe.FieldInfo;
 811
 812                                         if (fi.IsInitOnly) {
 813                                                 Error_InvalidNamedArgument (member_name);
 814                                                 return null;
 815                                         }
 816
 817                                         if (a.Expr is Constant) {
 818                                                 Constant c = (Constant) a.Expr;
 819
 820                                                 if (member_name == "CallingConvention")
 821                                                         cc = (CallingConvention) c.GetValue ();
 822                                                 else if (member_name == "CharSet")
 823                                                         charset = (CharSet) c.GetValue ();
 824                                                 else if (member_name == "EntryPoint")
 825                                                         entry_point = (string) c.GetValue ();
 826                                                 else if (member_name == "SetLastError")
 827                                                         set_last_err = (bool) c.GetValue ();
 828                                                 else if (member_name == "ExactSpelling")
 829                                                         exact_spelling = (bool) c.GetValue ();
 830                                                 else if (member_name == "PreserveSig")
 831                                                         preserve_sig = (bool) c.GetValue ();
 832                                         } else {
 833                                                 Error_AttributeArgumentNotValid ();
 834                                                 return null;
 835                                         }
 836
 837                                 }
 838                         }
 839
 840                         if (entry_point == null)
 841                                 entry_point = name;
 842
 843                         MethodBuilder mb = builder.DefinePInvokeMethod (
 844                                 name, dll_name, entry_point, flags | MethodAttributes.HideBySig,
 845                                 CallingConventions.Standard,
 846                                 ret_type,
 847                                 param_types,
 848                                 cc,
 849                                 charset);
 850
 851                         if (preserve_sig)
 852                                 mb.SetImplementationFlags (MethodImplAttributes.PreserveSig);
 853
 854                         return mb;
 855                 }
 856
 857         }
 858
 859         public class AttributeSection {
 860
 861                 public readonly string    Target;
 862                 public readonly ArrayList Attributes;
 863
 864                 public AttributeSection (string target, ArrayList attrs)
 865                 {
 866                         Target = target;
 867                         Attributes = attrs;
 868                 }
 869
 870         }
 871
 872         public class Attributes {
 873                 public ArrayList AttributeSections;
 874                 public Location Location;
 875
 876                 public Attributes (AttributeSection a, Location loc)
 877                 {
 878                         AttributeSections = new ArrayList ();
 879                         AttributeSections.Add (a);
 880
 881                 }
 882
 883                 public void AddAttribute (AttributeSection a)
 884                 {
 885                         if (a != null)
 886                                 AttributeSections.Add (a);
 887                 }
 888         }
 889 }