mcs/mcs/attribute.cs

   1 //
   2 // attribute.cs: Attribute Handler
   3 //
   4 // Author: Ravi Pratap (ravi@ximian.com)
   5 //         Marek Safar (marek.safar@seznam.cz)
   6 //
   7 // Dual licensed under the terms of the MIT X11 or GNU GPL
   8 //
   9 // Copyright 2001-2003 Ximian, Inc (http://www.ximian.com)
  10 // Copyright 2003-2008 Novell, Inc.
  11 //
  12
  13 using System;
  14 using System.Diagnostics;
  15 using System.Collections.Generic;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18 using System.Runtime.InteropServices;
  19 using System.Runtime.CompilerServices;
  20 using System.Security;
  21 using System.Security.Permissions;
  22 using System.Text;
  23 using System.IO;
  24
  25 namespace Mono.CSharp {
  26
  27         /// <summary>
  28         ///   Base class for objects that can have Attributes applied to them.
  29         /// </summary>
  30         public abstract class Attributable {
  31                 //
  32                 // Holds all attributes attached to this element
  33                 //
  34                 protected Attributes attributes;
  35
  36                 public void AddAttributes (Attributes attrs, IMemberContext context)
  37                 {
  38                         if (attrs == null)
  39                                 return;
  40
  41                         if (attributes == null)
  42                                 attributes = attrs;
  43                         else
  44                                 throw new NotImplementedException ();
  45
  46                         attributes.AttachTo (this, context);
  47                 }
  48
  49                 public Attributes OptAttributes {
  50                         get {
  51                                 return attributes;
  52                         }
  53                         set {
  54                                 attributes = value;
  55                         }
  56                 }
  57
  58                 /// <summary>
  59                 /// Use member-specific procedure to apply attribute @a in @cb to the entity being built in @builder
  60                 /// </summary>
  61                 public abstract void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb, PredefinedAttributes pa);
  62
  63                 /// <summary>
  64                 /// Returns one AttributeTarget for this element.
  65                 /// </summary>
  66                 public abstract AttributeTargets AttributeTargets { get; }
  67
  68                 public abstract bool IsClsComplianceRequired ();
  69
  70                 /// <summary>
  71                 /// Gets list of valid attribute targets for explicit target declaration.
  72                 /// The first array item is default target. Don't break this rule.
  73                 /// </summary>
  74                 public abstract string[] ValidAttributeTargets { get; }
  75         };
  76
  77         public class Attribute : Expression
  78         {
  79                 public readonly string ExplicitTarget;
  80                 public AttributeTargets Target;
  81                 readonly ATypeNameExpression expression;
  82
  83                 Arguments PosArguments;
  84                 Arguments NamedArguments;
  85
  86                 bool resolve_error;
  87                 readonly bool nameEscaped;
  88
  89                 //
  90                 // An attribute can be attached to multiple targets (e.g. multiple fields)
  91                 //
  92                 protected Attributable[] targets;
  93
  94                 //
  95                 // A member context for the attribute, it's much easier to hold it here
  96                 // than trying to pull it during resolve
  97                 //
  98                 IMemberContext context;
  99
 100                 static readonly AttributeUsageAttribute DefaultUsageAttribute = new AttributeUsageAttribute (AttributeTargets.All);
 101                 static Assembly orig_sec_assembly;
 102                 public static readonly object[] EmptyObject = new object [0];
 103
 104                 // non-null if named args present after Resolve () is called
 105                 PropertyInfo [] prop_info_arr;
 106                 FieldInfo [] field_info_arr;
 107                 object [] field_values_arr;
 108                 object [] prop_values_arr;
 109                 object [] pos_values;
 110
 111                 static Dictionary<Type, AttributeUsageAttribute> usage_attr_cache;
 112                 // Cache for parameter-less attributes
 113                 static Dictionary<Type, CustomAttributeBuilder> att_cache;
 114
 115                 public Attribute (string target, ATypeNameExpression expr, Arguments[] args, Location loc, bool nameEscaped)
 116                 {
 117                         this.expression = expr;
 118                         if (args != null) {
 119                                 PosArguments = args [0];
 120                                 NamedArguments = args [1];
 121                         }
 122                         this.loc = loc;
 123                         ExplicitTarget = target;
 124                         this.nameEscaped = nameEscaped;
 125                 }
 126
 127                 public Attribute Clone ()
 128                 {
 129                         Attribute a = new Attribute (ExplicitTarget, expression, null, loc, nameEscaped);
 130                         a.PosArguments = PosArguments;
 131                         a.NamedArguments = NamedArguments;
 132                         return a;
 133                 }
 134
 135                 static Attribute ()
 136                 {
 137                         Reset ();
 138                 }
 139
 140                 public static void Reset ()
 141                 {
 142                         usage_attr_cache = new Dictionary<Type, AttributeUsageAttribute> (ReferenceEquality<Type>.Default);
 143                         att_cache = new Dictionary<Type, CustomAttributeBuilder> (ReferenceEquality<Type>.Default);
 144                 }
 145
 146                 //
 147                 // When the same attribute is attached to multiple fiels
 148                 // we use @target field as a list of targets. The attribute
 149                 // has to be resolved only once but emitted for each target.
 150                 //
 151                 public virtual void AttachTo (Attributable target, IMemberContext context)
 152                 {
 153                         if (this.targets == null) {
 154                                 this.targets = new Attributable[] { target };
 155                                 this.context = context;
 156                                 return;
 157                         }
 158
 159                         // Resize target array
 160                         Attributable[] new_array = new Attributable [this.targets.Length + 1];
 161                         targets.CopyTo (new_array, 0);
 162                         new_array [targets.Length] = target;
 163                         this.targets = new_array;
 164
 165                         // No need to update context, different targets cannot have
 166                         // different contexts, it's enough to remove same attributes
 167                         // from secondary members.
 168
 169                         target.OptAttributes = null;
 170                 }
 171
 172                 static void Error_InvalidNamedArgument (ResolveContext rc, NamedArgument name)
 173                 {
 174                         rc.Report.Error (617, name.Location, "`{0}' is not a valid named attribute argument. Named attribute arguments " +
 175                                       "must be fields which are not readonly, static, const or read-write properties which are " +
 176                                       "public and not static",
 177                               name.Name);
 178                 }
 179
 180                 static void Error_InvalidNamedArgumentType (ResolveContext rc, NamedArgument name)
 181                 {
 182                         rc.Report.Error (655, name.Location,
 183                                 "`{0}' is not a valid named attribute argument because it is not a valid attribute parameter type",
 184                                 name.Name);
 185                 }
 186
 187                 public static void Error_AttributeArgumentNotValid (ResolveContext rc, Location loc)
 188                 {
 189                         rc.Report.Error (182, loc,
 190                                       "An attribute argument must be a constant expression, typeof " +
 191                                       "expression or array creation expression");
 192                 }
 193
 194                 public void Error_MissingGuidAttribute ()
 195                 {
 196                         Report.Error (596, Location, "The Guid attribute must be specified with the ComImport attribute");
 197                 }
 198
 199                 public void Error_MisusedExtensionAttribute ()
 200                 {
 201                         Report.Error (1112, Location, "Do not use `{0}' directly. Use parameter modifier `this' instead", GetSignatureForError ());
 202                 }
 203
 204                 public void Error_MisusedDynamicAttribute ()
 205                 {
 206                         Report.Error (1970, loc, "Do not use `{0}' directly. Use `dynamic' keyword instead", GetSignatureForError ());
 207                 }
 208
 209                 /// <summary>
 210                 /// This is rather hack. We report many emit attribute error with same error to be compatible with
 211                 /// csc. But because csc has to report them this way because error came from ilasm we needn't.
 212                 /// </summary>
 213                 public void Error_AttributeEmitError (string inner)
 214                 {
 215                         Report.Error (647, Location, "Error during emitting `{0}' attribute. The reason is `{1}'",
 216                                       TypeManager.CSharpName (Type), inner);
 217                 }
 218
 219                 public void Error_InvalidSecurityParent ()
 220                 {
 221                         Error_AttributeEmitError ("it is attached to invalid parent");
 222                 }
 223
 224                 Attributable Owner {
 225                         get {
 226                                 return targets [0];
 227                         }
 228                 }
 229
 230                 protected virtual TypeExpr ResolveAsTypeTerminal (Expression expr, IMemberContext ec)
 231                 {
 232                         return expr.ResolveAsTypeTerminal (ec, false);
 233                 }
 234
 235                 Type ResolvePossibleAttributeType (ATypeNameExpression expr, ref bool is_attr)
 236                 {
 237                         TypeExpr te = ResolveAsTypeTerminal (expr, context);
 238                         if (te == null)
 239                                 return null;
 240
 241                         Type t = te.Type;
 242                         if (TypeManager.IsSubclassOf (t, TypeManager.attribute_type)) {
 243                                 is_attr = true;
 244                         } else {
 245                                 Report.SymbolRelatedToPreviousError (t);
 246                                 Report.Error (616, Location, "`{0}': is not an attribute class", TypeManager.CSharpName (t));
 247                         }
 248                         return t;
 249                 }
 250
 251                 /// <summary>
 252                 ///   Tries to resolve the type of the attribute. Flags an error if it can't, and complain is true.
 253                 /// </summary>
 254                 void ResolveAttributeType ()
 255                 {
 256                         SessionReportPrinter resolve_printer = new SessionReportPrinter ();
 257                         ReportPrinter prev_recorder = context.Compiler.Report.SetPrinter (resolve_printer);
 258
 259                         bool t1_is_attr = false;
 260                         bool t2_is_attr = false;
 261                         Type t1, t2;
 262                         ATypeNameExpression expanded = null;
 263
 264                         try {
 265                                 t1 = ResolvePossibleAttributeType (expression, ref t1_is_attr);
 266
 267                                 if (nameEscaped) {
 268                                         t2 = null;
 269                                 } else {
 270                                         expanded = (ATypeNameExpression) expression.Clone (null);
 271                                         expanded.Name += "Attribute";
 272
 273                                         t2 = ResolvePossibleAttributeType (expanded, ref t2_is_attr);
 274                                 }
 275
 276                                 resolve_printer.EndSession ();
 277                         } finally {
 278                                 context.Compiler.Report.SetPrinter (prev_recorder);
 279                         }
 280
 281                         if (t1_is_attr && t2_is_attr) {
 282                                 Report.Error (1614, Location, "`{0}' is ambiguous between `{1}' and `{2}'. Use either `@{0}' or `{0}Attribute'",
 283                                         GetSignatureForError (), expression.GetSignatureForError (), expanded.GetSignatureForError ());
 284                                 resolve_error = true;
 285                                 return;
 286                         }
 287
 288                         if (t1_is_attr) {
 289                                 Type = t1;
 290                                 return;
 291                         }
 292
 293                         if (t2_is_attr) {
 294                                 Type = t2;
 295                                 return;
 296                         }
 297
 298                         resolve_printer.Merge (prev_recorder);
 299                         resolve_error = true;
 300                 }
 301
 302                 public virtual Type ResolveType ()
 303                 {
 304                         if (Type == null && !resolve_error)
 305                                 ResolveAttributeType ();
 306                         return Type;
 307                 }
 308
 309                 public override string GetSignatureForError ()
 310                 {
 311                         if (Type != null)
 312                                 return TypeManager.CSharpName (Type);
 313
 314                         return expression.GetSignatureForError ();
 315                 }
 316
 317                 public bool HasSecurityAttribute {
 318                         get {
 319                                 PredefinedAttribute pa = PredefinedAttributes.Get.Security;
 320                                 return pa.IsDefined && TypeManager.IsSubclassOf (type, pa.Type);
 321                         }
 322                 }
 323
 324                 public bool IsValidSecurityAttribute ()
 325                 {
 326                         return HasSecurityAttribute && IsSecurityActionValid (false);
 327                 }
 328
 329                 static bool IsValidArgumentType (Type t)
 330                 {
 331                         if (t.IsArray)
 332                                 t = TypeManager.GetElementType (t);
 333
 334                         return t == TypeManager.string_type ||
 335                                 TypeManager.IsPrimitiveType (t) ||
 336                                 TypeManager.IsEnumType (t) ||
 337                                 t == TypeManager.object_type ||
 338                                 t == TypeManager.type_type;
 339                 }
 340
 341                 // TODO: Don't use this ambiguous value
 342                 public string Name {
 343                         get { return expression.Name; }
 344                 }
 345
 346                 void ApplyModuleCharSet (ResolveContext rc)
 347                 {
 348                         if (Type != PredefinedAttributes.Get.DllImport)
 349                                 return;
 350
 351                         if (!RootContext.ToplevelTypes.HasDefaultCharSet)
 352                                 return;
 353
 354                         const string CharSetEnumMember = "CharSet";
 355                         if (NamedArguments == null) {
 356                                 NamedArguments = new Arguments (1);
 357                         } else {
 358                                 foreach (NamedArgument a in NamedArguments) {
 359                                         if (a.Name == CharSetEnumMember)
 360                                                 return;
 361                                 }
 362                         }
 363
 364                         NamedArguments.Add (new NamedArgument (CharSetEnumMember, loc,
 365                                 Constant.CreateConstant (rc, typeof (CharSet), RootContext.ToplevelTypes.DefaultCharSet, Location)));
 366                 }
 367
 368                 public Report Report {
 369                         get { return context.Compiler.Report; }
 370                 }
 371
 372                 public CustomAttributeBuilder Resolve ()
 373                 {
 374                         if (resolve_error)
 375                                 return null;
 376
 377                         resolve_error = true;
 378
 379                         if (Type == null) {
 380                                 ResolveAttributeType ();
 381                                 if (Type == null)
 382                                         return null;
 383                         }
 384
 385                         if (Type.IsAbstract) {
 386                                 Report.Error (653, Location, "Cannot apply attribute class `{0}' because it is abstract", GetSignatureForError ());
 387                                 return null;
 388                         }
 389
 390                         ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (Type);
 391                         if (obsolete_attr != null) {
 392                                 AttributeTester.Report_ObsoleteMessage (obsolete_attr, TypeManager.CSharpName (Type), Location, Report);
 393                         }
 394
 395                         CustomAttributeBuilder cb;
 396                         if (PosArguments == null && NamedArguments == null) {
 397                                 if (att_cache.TryGetValue (Type, out cb)) {
 398                                         resolve_error = false;
 399                                         return cb;
 400                                 }
 401                         }
 402
 403                         ResolveContext rc = new ResolveContext (context, ResolveContext.Options.ConstantScope);
 404                         var ctor = ResolveConstructor (rc);
 405                         if (ctor == null) {
 406                                 if (Type is TypeBuilder &&
 407                                     TypeManager.LookupDeclSpace (Type).MemberCache == null)
 408                                         // The attribute type has been DefineType'd, but not Defined.  Let's not treat it as an error.
 409                                         // It'll be resolved again when the attached-to entity is emitted.
 410                                         resolve_error = false;
 411                                 return null;
 412                         }
 413
 414                         ApplyModuleCharSet (rc);
 415
 416                         try {
 417                                 var ctor_meta = (ConstructorInfo) ctor.MetaInfo;
 418                                 // SRE does not allow private ctor but we want to report all source code errors
 419                                 if (ctor.MetaInfo.IsPrivate)
 420                                         return null;
 421
 422                                 if (NamedArguments == null) {
 423                                         cb = new CustomAttributeBuilder (ctor_meta, pos_values);
 424
 425                                         if (pos_values.Length == 0)
 426                                                 att_cache.Add (Type, cb);
 427
 428                                         resolve_error = false;
 429                                         return cb;
 430                                 }
 431
 432                                 if (!ResolveNamedArguments (rc)) {
 433                                         return null;
 434                                 }
 435
 436                                 cb = new CustomAttributeBuilder (ctor_meta, pos_values,
 437                                                 prop_info_arr, prop_values_arr,
 438                                                 field_info_arr, field_values_arr);
 439
 440                                 resolve_error = false;
 441                                 return cb;
 442                         }
 443                         catch (Exception) {
 444                                 Error_AttributeArgumentNotValid (rc, Location);
 445                                 return null;
 446                         }
 447                 }
 448
 449                 protected virtual MethodSpec ResolveConstructor (ResolveContext ec)
 450                 {
 451                         if (PosArguments != null) {
 452                                 bool dynamic;
 453                                 PosArguments.Resolve (ec, out dynamic);
 454                                 if (dynamic) {
 455                                         Error_AttributeArgumentNotValid (ec, loc);
 456                                         return null;
 457                                 }
 458                         }
 459
 460                         MethodGroupExpr mg = MemberLookupFinal (ec, ec.CurrentType,
 461                                 Type, ConstructorInfo.ConstructorName, MemberTypes.Constructor,
 462                                 BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly,
 463                                 Location) as MethodGroupExpr;
 464
 465                         if (mg == null)
 466                                 throw new NotImplementedException ();
 467
 468                         mg = mg.OverloadResolve (ec, ref PosArguments, false, Location);
 469                         if (mg == null)
 470                                 return null;
 471
 472                         var constructor = (MethodSpec) mg;
 473                         if (PosArguments == null) {
 474                                 pos_values = EmptyObject;
 475                                 return constructor;
 476                         }
 477
 478                         if (!PosArguments.GetAttributableValue (ec, out pos_values))
 479                                 return null;
 480
 481                         // Here we do the checks which should be done by corlib or by runtime.
 482                         // However Zoltan doesn't like it and every Mono compiler has to do it again.
 483                         PredefinedAttributes pa = PredefinedAttributes.Get;
 484                         if (Type == pa.Guid) {
 485                                 try {
 486                                         new Guid ((string)pos_values [0]);
 487                                 }
 488                                 catch (Exception e) {
 489                                         Error_AttributeEmitError (e.Message);
 490                                         return null;
 491                                 }
 492                         }
 493
 494                         if (Type == pa.AttributeUsage && (int)pos_values [0] == 0) {
 495                                 ec.Report.Error (591, Location, "Invalid value for argument to `System.AttributeUsage' attribute");
 496                                 return null;
 497                         }
 498
 499                         if (Type == pa.IndexerName || Type == pa.Conditional) {
 500                                 string v = pos_values [0] as string;
 501                                 if (!Tokenizer.IsValidIdentifier (v) || Tokenizer.IsKeyword (v)) {
 502                                         ec.Report.Error (633, PosArguments [0].Expr.Location,
 503                                                 "The argument to the `{0}' attribute must be a valid identifier", GetSignatureForError ());
 504                                         return null;
 505                                 }
 506                         }
 507
 508                         if (Type == pa.MethodImpl && pos_values.Length == 1 &&
 509                                 constructor.Parameters.Types [0] == TypeManager.short_type &&
 510                                 !System.Enum.IsDefined (typeof (MethodImplOptions), pos_values [0].ToString ())) {
 511                                 Error_AttributeEmitError ("Incorrect argument value.");
 512                                 return null;
 513                         }
 514
 515                         return constructor;
 516                 }
 517
 518                 protected virtual bool ResolveNamedArguments (ResolveContext ec)
 519                 {
 520                         int named_arg_count = NamedArguments.Count;
 521
 522                         var field_infos = new List<FieldInfo> (named_arg_count);
 523                         var prop_infos  = new List<PropertyInfo> (named_arg_count);
 524                         var field_values = new List<object> (named_arg_count);
 525                         var prop_values = new List<object> (named_arg_count);
 526
 527                         var seen_names = new List<string> (named_arg_count);
 528
 529                         foreach (NamedArgument a in NamedArguments) {
 530                                 string name = a.Name;
 531                                 if (seen_names.Contains (name)) {
 532                                         ec.Report.Error (643, a.Location, "Duplicate named attribute `{0}' argument", name);
 533                                         continue;
 534                                 }
 535
 536                                 seen_names.Add (name);
 537
 538                                 a.Resolve (ec);
 539
 540                                 Expression member = Expression.MemberLookup (ec.Compiler,
 541                                         ec.CurrentType, Type, name,
 542                                         MemberTypes.All,
 543                                         BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static,
 544                                         Location);
 545
 546                                 if (member == null) {
 547                                         member = Expression.MemberLookup (ec.Compiler, ec.CurrentType, Type, name,
 548                                                 MemberTypes.All, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static,
 549                                                 Location);
 550
 551                                         if (member != null) {
 552                                                 ec.Report.SymbolRelatedToPreviousError (member.Type);
 553                                                 Expression.ErrorIsInaccesible (Location, member.GetSignatureForError (), ec.Report);
 554                                                 return false;
 555                                         }
 556                                 }
 557
 558                                 if (member == null){
 559                                         Expression.Error_TypeDoesNotContainDefinition (ec, Location, Type, name);
 560                                         return false;
 561                                 }
 562
 563                                 if (!(member is PropertyExpr || member is FieldExpr)) {
 564                                         Error_InvalidNamedArgument (ec, a);
 565                                         return false;
 566                                 }
 567
 568                                 ObsoleteAttribute obsolete_attr;
 569
 570                                 if (member is PropertyExpr) {
 571                                         PropertyInfo pi = ((PropertyExpr) member).PropertyInfo;
 572
 573                                         if (!pi.CanWrite || !pi.CanRead || pi.GetGetMethod ().IsStatic) {
 574                                                 ec.Report.SymbolRelatedToPreviousError (pi);
 575                                                 Error_InvalidNamedArgument (ec, a);
 576                                                 return false;
 577                                         }
 578
 579                                         if (!IsValidArgumentType (member.Type)) {
 580                                                 ec.Report.SymbolRelatedToPreviousError (pi);
 581                                                 Error_InvalidNamedArgumentType (ec, a);
 582                                                 return false;
 583                                         }
 584
 585                                         object value;
 586                                         if (!a.Expr.GetAttributableValue (ec, member.Type, out value))
 587                                                 return false;
 588
 589                                         PropertyBase pb = TypeManager.GetProperty (pi);
 590                                         if (pb != null)
 591                                                 obsolete_attr = pb.GetObsoleteAttribute ();
 592                                         else
 593                                                 obsolete_attr = AttributeTester.GetMemberObsoleteAttribute (pi);
 594
 595                                         prop_values.Add (value);
 596                                         prop_infos.Add (pi);
 597
 598                                 } else {
 599                                         var fi = ((FieldExpr) member).Spec;
 600
 601                                         if (fi.IsReadOnly || fi.IsStatic) {
 602                                                 Error_InvalidNamedArgument (ec, a);
 603                                                 return false;
 604                                         }
 605
 606                                         if (!IsValidArgumentType (member.Type)) {
 607                                                 ec.Report.SymbolRelatedToPreviousError (fi.MetaInfo);
 608                                                 Error_InvalidNamedArgumentType (ec, a);
 609                                                 return false;
 610                                         }
 611
 612                                         object value;
 613                                         if (!a.Expr.GetAttributableValue (ec, member.Type, out value))
 614                                                 return false;
 615
 616                                         FieldBase fb = TypeManager.GetField (fi.MetaInfo);
 617                                         if (fb != null)
 618                                                 obsolete_attr = fb.GetObsoleteAttribute ();
 619                                         else
 620                                                 obsolete_attr = AttributeTester.GetMemberObsoleteAttribute (fi.MetaInfo);
 621
 622                                         field_values.Add (value);
 623                                         field_infos.Add (fi.MetaInfo);
 624                                 }
 625
 626                                 if (obsolete_attr != null && !context.IsObsolete)
 627                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, member.GetSignatureForError (), member.Location, Report);
 628                         }
 629
 630                         prop_info_arr = new PropertyInfo [prop_infos.Count];
 631                         field_info_arr = new FieldInfo [field_infos.Count];
 632                         field_values_arr = new object [field_values.Count];
 633                         prop_values_arr = new object [prop_values.Count];
 634
 635                         field_infos.CopyTo  (field_info_arr, 0);
 636                         field_values.CopyTo (field_values_arr, 0);
 637
 638                         prop_values.CopyTo  (prop_values_arr, 0);
 639                         prop_infos.CopyTo   (prop_info_arr, 0);
 640
 641                         return true;
 642                 }
 643
 644                 /// <summary>
 645                 ///   Get a string containing a list of valid targets for the attribute 'attr'
 646                 /// </summary>
 647                 public string GetValidTargets ()
 648                 {
 649                         StringBuilder sb = new StringBuilder ();
 650                         AttributeTargets targets = GetAttributeUsage (Type).ValidOn;
 651
 652                         if ((targets & AttributeTargets.Assembly) != 0)
 653                                 sb.Append ("assembly, ");
 654
 655                         if ((targets & AttributeTargets.Module) != 0)
 656                                 sb.Append ("module, ");
 657
 658                         if ((targets & AttributeTargets.Class) != 0)
 659                                 sb.Append ("class, ");
 660
 661                         if ((targets & AttributeTargets.Struct) != 0)
 662                                 sb.Append ("struct, ");
 663
 664                         if ((targets & AttributeTargets.Enum) != 0)
 665                                 sb.Append ("enum, ");
 666
 667                         if ((targets & AttributeTargets.Constructor) != 0)
 668                                 sb.Append ("constructor, ");
 669
 670                         if ((targets & AttributeTargets.Method) != 0)
 671                                 sb.Append ("method, ");
 672
 673                         if ((targets & AttributeTargets.Property) != 0)
 674                                 sb.Append ("property, indexer, ");
 675
 676                         if ((targets & AttributeTargets.Field) != 0)
 677                                 sb.Append ("field, ");
 678
 679                         if ((targets & AttributeTargets.Event) != 0)
 680                                 sb.Append ("event, ");
 681
 682                         if ((targets & AttributeTargets.Interface) != 0)
 683                                 sb.Append ("interface, ");
 684
 685                         if ((targets & AttributeTargets.Parameter) != 0)
 686                                 sb.Append ("parameter, ");
 687
 688                         if ((targets & AttributeTargets.Delegate) != 0)
 689                                 sb.Append ("delegate, ");
 690
 691                         if ((targets & AttributeTargets.ReturnValue) != 0)
 692                                 sb.Append ("return, ");
 693
 694                         if ((targets & AttributeTargets.GenericParameter) != 0)
 695                                 sb.Append ("type parameter, ");
 696
 697                         return sb.Remove (sb.Length - 2, 2).ToString ();
 698                 }
 699
 700                 /// <summary>
 701                 /// Returns AttributeUsage attribute based on types hierarchy
 702                 /// </summary>
 703                 static AttributeUsageAttribute GetAttributeUsage (Type type)
 704                 {
 705                         AttributeUsageAttribute ua;
 706                         if (usage_attr_cache.TryGetValue (type, out ua))
 707                                 return ua;
 708
 709                         Class attr_class = TypeManager.LookupClass (type);
 710                         PredefinedAttribute pa = PredefinedAttributes.Get.AttributeUsage;
 711
 712                         if (attr_class == null) {
 713                                 if (!pa.IsDefined)
 714                                         return new AttributeUsageAttribute (0);
 715
 716                                 object[] usage_attr = type.GetCustomAttributes (pa.Type, true);
 717                                 ua = (AttributeUsageAttribute)usage_attr [0];
 718                                 usage_attr_cache.Add (type, ua);
 719                                 return ua;
 720                         }
 721
 722                         Attribute a = null;
 723                         if (attr_class.OptAttributes != null)
 724                                 a = attr_class.OptAttributes.Search (pa);
 725
 726                         if (a == null) {
 727                                 if (attr_class.TypeBuilder.BaseType != TypeManager.attribute_type)
 728                                         ua = GetAttributeUsage (attr_class.TypeBuilder.BaseType);
 729                                 else
 730                                         ua = DefaultUsageAttribute;
 731                         } else {
 732                                 ua = a.GetAttributeUsageAttribute ();
 733                         }
 734
 735                         usage_attr_cache.Add (type, ua);
 736                         return ua;
 737                 }
 738
 739                 AttributeUsageAttribute GetAttributeUsageAttribute ()
 740                 {
 741                         if (pos_values == null)
 742                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 743                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 744                                 Resolve ();
 745
 746                         if (resolve_error)
 747                                 return DefaultUsageAttribute;
 748
 749                         AttributeUsageAttribute usage_attribute = new AttributeUsageAttribute ((AttributeTargets)pos_values [0]);
 750
 751                         object field = GetPropertyValue ("AllowMultiple");
 752                         if (field != null)
 753                                 usage_attribute.AllowMultiple = (bool)field;
 754
 755                         field = GetPropertyValue ("Inherited");
 756                         if (field != null)
 757                                 usage_attribute.Inherited = (bool)field;
 758
 759                         return usage_attribute;
 760                 }
 761
 762                 /// <summary>
 763                 /// Returns custom name of indexer
 764                 /// </summary>
 765                 public string GetIndexerAttributeValue ()
 766                 {
 767                         if (pos_values == null)
 768                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 769                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 770                                 Resolve ();
 771
 772                         if (resolve_error)
 773                                 return null;
 774
 775                         return pos_values [0] as string;
 776                 }
 777
 778                 /// <summary>
 779                 /// Returns condition of ConditionalAttribute
 780                 /// </summary>
 781                 public string GetConditionalAttributeValue ()
 782                 {
 783                         if (pos_values == null)
 784                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 785                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 786                                 Resolve ();
 787
 788                         if (resolve_error)
 789                                 return null;
 790
 791                         return (string)pos_values [0];
 792                 }
 793
 794                 /// <summary>
 795                 /// Creates the instance of ObsoleteAttribute from this attribute instance
 796                 /// </summary>
 797                 public ObsoleteAttribute GetObsoleteAttribute ()
 798                 {
 799                         if (pos_values == null)
 800                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 801                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 802                                 Resolve ();
 803
 804                         if (resolve_error)
 805                                 return null;
 806
 807                         if (pos_values == null || pos_values.Length == 0)
 808                                 return new ObsoleteAttribute ();
 809
 810                         if (pos_values.Length == 1)
 811                                 return new ObsoleteAttribute ((string)pos_values [0]);
 812
 813                         return new ObsoleteAttribute ((string)pos_values [0], (bool)pos_values [1]);
 814                 }
 815
 816                 /// <summary>
 817                 /// Returns value of CLSCompliantAttribute contructor parameter but because the method can be called
 818                 /// before ApplyAttribute. We need to resolve the arguments.
 819                 /// This situation occurs when class deps is differs from Emit order.
 820                 /// </summary>
 821                 public bool GetClsCompliantAttributeValue ()
 822                 {
 823                         if (pos_values == null)
 824                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 825                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 826                                 Resolve ();
 827
 828                         if (resolve_error)
 829                                 return false;
 830
 831                         return (bool)pos_values [0];
 832                 }
 833
 834                 public Type GetCoClassAttributeValue ()
 835                 {
 836                         if (pos_values == null)
 837                                 Resolve ();
 838
 839                         if (resolve_error)
 840                                 return null;
 841
 842                         return (Type)pos_values [0];
 843                 }
 844
 845                 public bool CheckTarget ()
 846                 {
 847                         string[] valid_targets = Owner.ValidAttributeTargets;
 848                         if (ExplicitTarget == null || ExplicitTarget == valid_targets [0]) {
 849                                 Target = Owner.AttributeTargets;
 850                                 return true;
 851                         }
 852
 853                         // TODO: we can skip the first item
 854                         if (Array.Exists (valid_targets, i => i == ExplicitTarget)) {
 855                                 switch (ExplicitTarget) {
 856                                 case "return": Target = AttributeTargets.ReturnValue; return true;
 857                                 case "param": Target = AttributeTargets.Parameter; return true;
 858                                 case "field": Target = AttributeTargets.Field; return true;
 859                                 case "method": Target = AttributeTargets.Method; return true;
 860                                 case "property": Target = AttributeTargets.Property; return true;
 861                                 }
 862                                 throw new InternalErrorException ("Unknown explicit target: " + ExplicitTarget);
 863                         }
 864
 865                         StringBuilder sb = new StringBuilder ();
 866                         foreach (string s in valid_targets) {
 867                                 sb.Append (s);
 868                                 sb.Append (", ");
 869                         }
 870                         sb.Remove (sb.Length - 2, 2);
 871                         Report.Error (657, Location, "`{0}' is not a valid attribute location for this declaration. " +
 872                                 "Valid attribute locations for this declaration are `{1}'", ExplicitTarget, sb.ToString ());
 873                         return false;
 874                 }
 875
 876                 /// <summary>
 877                 /// Tests permitted SecurityAction for assembly or other types
 878                 /// </summary>
 879                 protected virtual bool IsSecurityActionValid (bool for_assembly)
 880                 {
 881                         SecurityAction action = GetSecurityActionValue ();
 882
 883                         switch (action) {
 884                         case SecurityAction.Demand:
 885                         case SecurityAction.Assert:
 886                         case SecurityAction.Deny:
 887                         case SecurityAction.PermitOnly:
 888                         case SecurityAction.LinkDemand:
 889                         case SecurityAction.InheritanceDemand:
 890                                 if (!for_assembly)
 891                                         return true;
 892                                 break;
 893
 894                         case SecurityAction.RequestMinimum:
 895                         case SecurityAction.RequestOptional:
 896                         case SecurityAction.RequestRefuse:
 897                                 if (for_assembly)
 898                                         return true;
 899                                 break;
 900
 901                         default:
 902                                 Error_AttributeEmitError ("SecurityAction is out of range");
 903                                 return false;
 904                         }
 905
 906                         Error_AttributeEmitError (String.Concat ("SecurityAction `", action, "' is not valid for this declaration"));
 907                         return false;
 908                 }
 909
 910                 System.Security.Permissions.SecurityAction GetSecurityActionValue ()
 911                 {
 912                         return (SecurityAction)pos_values [0];
 913                 }
 914
 915                 /// <summary>
 916                 /// Creates instance of SecurityAttribute class and add result of CreatePermission method to permission table.
 917                 /// </summary>
 918                 /// <returns></returns>
 919                 public void ExtractSecurityPermissionSet (Dictionary<SecurityAction, PermissionSet> permissions)
 920                 {
 921                         Type orig_assembly_type = null;
 922
 923                         if (TypeManager.LookupDeclSpace (Type) != null) {
 924                                 if (!RootContext.StdLib) {
 925                                         orig_assembly_type = Type.GetType (Type.FullName);
 926                                 } else {
 927                                         string orig_version_path = Environment.GetEnvironmentVariable ("__SECURITY_BOOTSTRAP_DB");
 928                                         if (orig_version_path == null) {
 929                                                 Error_AttributeEmitError ("security custom attributes can not be referenced from defining assembly");
 930                                                 return;
 931                                         }
 932
 933                                         if (orig_sec_assembly == null) {
 934                                                 string file = Path.Combine (orig_version_path, Driver.OutputFile);
 935                                                 orig_sec_assembly = Assembly.LoadFile (file);
 936                                         }
 937
 938                                         orig_assembly_type = orig_sec_assembly.GetType (Type.FullName, true);
 939                                         if (orig_assembly_type == null) {
 940                                                 Report.Warning (-112, 1, Location, "Self-referenced security attribute `{0}' " +
 941                                                                 "was not found in previous version of assembly");
 942                                                 return;
 943                                         }
 944                                 }
 945                         }
 946
 947                         SecurityAttribute sa;
 948                         // For all non-selfreferencing security attributes we can avoid all hacks
 949                         if (orig_assembly_type == null) {
 950                                 sa = (SecurityAttribute) Activator.CreateInstance (Type, pos_values);
 951
 952                                 if (prop_info_arr != null) {
 953                                         for (int i = 0; i < prop_info_arr.Length; ++i) {
 954                                                 PropertyInfo pi = prop_info_arr [i];
 955                                                 pi.SetValue (sa, prop_values_arr [i], null);
 956                                         }
 957                                 }
 958                         } else {
 959                                 // HACK: All security attributes have same ctor syntax
 960                                 sa = (SecurityAttribute) Activator.CreateInstance (orig_assembly_type, new object[] { GetSecurityActionValue () } );
 961
 962                                 // All types are from newly created assembly but for invocation with old one we need to convert them
 963                                 if (prop_info_arr != null) {
 964                                         for (int i = 0; i < prop_info_arr.Length; ++i) {
 965                                                 PropertyInfo emited_pi = prop_info_arr [i];
 966                                                 // FIXME: We are missing return type filter
 967                                                 // TODO: pi can be null
 968                                                 PropertyInfo pi = orig_assembly_type.GetProperty (emited_pi.Name);
 969
 970                                                 object old_instance = TypeManager.IsEnumType (pi.PropertyType) ?
 971                                                         System.Enum.ToObject (pi.PropertyType, prop_values_arr [i]) :
 972                                                         prop_values_arr [i];
 973
 974                                                 pi.SetValue (sa, old_instance, null);
 975                                         }
 976                                 }
 977                         }
 978
 979                         IPermission perm;
 980                         perm = sa.CreatePermission ();
 981                         SecurityAction action = GetSecurityActionValue ();
 982
 983                         // IS is correct because for corlib we are using an instance from old corlib
 984                         if (!(perm is System.Security.CodeAccessPermission)) {
 985                                 switch (action) {
 986                                 case SecurityAction.Demand:
 987                                         action = (SecurityAction)13;
 988                                         break;
 989                                 case SecurityAction.LinkDemand:
 990                                         action = (SecurityAction)14;
 991                                         break;
 992                                 case SecurityAction.InheritanceDemand:
 993                                         action = (SecurityAction)15;
 994                                         break;
 995                                 }
 996                         }
 997
 998                         PermissionSet ps;
 999                         if (!permissions.TryGetValue (action, out ps)) {
1000                                 if (sa is PermissionSetAttribute)
1001                                         ps = new PermissionSet (sa.Unrestricted ? PermissionState.Unrestricted : PermissionState.None);
1002                                 else
1003                                         ps = new PermissionSet (PermissionState.None);
1004
1005                                 permissions.Add (action, ps);
1006                         } else if (!ps.IsUnrestricted () && (sa is PermissionSetAttribute) && sa.Unrestricted) {
1007                                 ps = ps.Union (new PermissionSet (PermissionState.Unrestricted));
1008                                 permissions [action] = ps;
1009                         }
1010                         ps.AddPermission (perm);
1011                 }
1012
1013                 public object GetPropertyValue (string name)
1014                 {
1015                         if (prop_info_arr == null)
1016                                 return null;
1017
1018                         for (int i = 0; i < prop_info_arr.Length; ++i) {
1019                                 if (prop_info_arr [i].Name == name)
1020                                         return prop_values_arr [i];
1021                         }
1022
1023                         return null;
1024                 }
1025
1026                 //
1027                 // Theoretically, we can get rid of this, since FieldBuilder.SetCustomAttribute()
1028                 // and ParameterBuilder.SetCustomAttribute() are supposed to handle this attribute.
1029                 // However, we can't, since it appears that the .NET 1.1 SRE hangs when given a MarshalAsAttribute.
1030                 //
1031 #if false
1032                 public UnmanagedMarshal GetMarshal (Attributable attr)
1033                 {
1034                         UnmanagedType UnmanagedType;
1035                         if (!RootContext.StdLib || pos_values [0].GetType () != typeof (UnmanagedType))
1036                                 UnmanagedType = (UnmanagedType) System.Enum.ToObject (typeof (UnmanagedType), pos_values [0]);
1037                         else
1038                                 UnmanagedType = (UnmanagedType) pos_values [0];
1039
1040                         object value = GetFieldValue ("SizeParamIndex");
1041                         if (value != null && UnmanagedType != UnmanagedType.LPArray) {
1042                                 Error_AttributeEmitError ("SizeParamIndex field is not valid for the specified unmanaged type");
1043                                 return null;
1044                         }
1045
1046                         object o = GetFieldValue ("ArraySubType");
1047                         UnmanagedType array_sub_type = o == null ? (UnmanagedType) 0x50 /* NATIVE_MAX */ : (UnmanagedType) o;
1048
1049                         switch (UnmanagedType) {
1050                         case UnmanagedType.CustomMarshaler: {
1051                                 MethodInfo define_custom = typeof (UnmanagedMarshal).GetMethod ("DefineCustom",
1052                                         BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
1053                                 if (define_custom == null) {
1054                                         Report.RuntimeMissingSupport (Location, "set marshal info");
1055                                         return null;
1056                                 }
1057
1058                                 object [] args = new object [4];
1059                                 args [0] = GetFieldValue ("MarshalTypeRef");
1060                                 args [1] = GetFieldValue ("MarshalCookie");
1061                                 args [2] = GetFieldValue ("MarshalType");
1062                                 args [3] = Guid.Empty;
1063                                 return (UnmanagedMarshal) define_custom.Invoke (null, args);
1064                         }
1065                         case UnmanagedType.LPArray: {
1066                                 object size_const = GetFieldValue ("SizeConst");
1067                                 object size_param_index = GetFieldValue ("SizeParamIndex");
1068
1069                                 if ((size_const != null) || (size_param_index != null)) {
1070                                         MethodInfo define_array = typeof (UnmanagedMarshal).GetMethod ("DefineLPArrayInternal",
1071                                                 BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
1072                                         if (define_array == null) {
1073                                                 Report.RuntimeMissingSupport (Location, "set marshal info");
1074                                                 return null;
1075                                         }
1076
1077                                         object [] args = new object [3];
1078                                         args [0] = array_sub_type;
1079                                         args [1] = size_const == null ? -1 : size_const;
1080                                         args [2] = size_param_index == null ? -1 : size_param_index;
1081                                         return (UnmanagedMarshal) define_array.Invoke (null, args);
1082                                 }
1083                                 else
1084                                         return UnmanagedMarshal.DefineLPArray (array_sub_type);
1085                         }
1086                         case UnmanagedType.SafeArray:
1087                                 return UnmanagedMarshal.DefineSafeArray (array_sub_type);
1088
1089                         case UnmanagedType.ByValArray:
1090                                 FieldBase fm = attr as FieldBase;
1091                                 if (fm == null) {
1092                                         Error_AttributeEmitError ("Specified unmanaged type is only valid on fields");
1093                                         return null;
1094                                 }
1095                                 return UnmanagedMarshal.DefineByValArray ((int) GetFieldValue ("SizeConst"));
1096
1097                         case UnmanagedType.ByValTStr:
1098                                 return UnmanagedMarshal.DefineByValTStr ((int) GetFieldValue ("SizeConst"));
1099
1100                         default:
1101                                 return UnmanagedMarshal.DefineUnmanagedMarshal (UnmanagedType);
1102                         }
1103                 }
1104
1105                 object GetFieldValue (string name)
1106                 {
1107                         int i;
1108                         if (field_info_arr == null)
1109                                 return null;
1110                         i = 0;
1111                         foreach (FieldInfo fi in field_info_arr) {
1112                                 if (fi.Name == name)
1113                                         return GetValue (field_values_arr [i]);
1114                                 i++;
1115                         }
1116                         return null;
1117                 }
1118
1119                 static object GetValue (object value)
1120                 {
1121                         if (value is EnumConstant)
1122                                 return ((EnumConstant) value).GetValue ();
1123                         else
1124                                 return value;
1125                 }
1126
1127 #endif
1128
1129                 public CharSet GetCharSetValue ()
1130                 {
1131                         return (CharSet)System.Enum.Parse (typeof (CharSet), pos_values [0].ToString ());
1132                 }
1133
1134                 public bool HasField (string fieldName)
1135                 {
1136                         if (field_info_arr == null)
1137                                 return false;
1138
1139                         foreach (FieldInfo fi in field_info_arr) {
1140                                 if (fi.Name == fieldName)
1141                                         return true;
1142                         }
1143
1144                         return false;
1145                 }
1146
1147                 public bool IsInternalMethodImplAttribute {
1148                         get {
1149                                 if (Type != PredefinedAttributes.Get.MethodImpl)
1150                                         return false;
1151
1152                                 MethodImplOptions options;
1153                                 if (pos_values[0].GetType () != typeof (MethodImplOptions))
1154                                         options = (MethodImplOptions)System.Enum.ToObject (typeof (MethodImplOptions), pos_values[0]);
1155                                 else
1156                                         options = (MethodImplOptions)pos_values[0];
1157
1158                                 return (options & MethodImplOptions.InternalCall) != 0;
1159                         }
1160                 }
1161
1162                 public LayoutKind GetLayoutKindValue ()
1163                 {
1164                         if (!RootContext.StdLib || pos_values [0].GetType () != typeof (LayoutKind))
1165                                 return (LayoutKind)System.Enum.ToObject (typeof (LayoutKind), pos_values [0]);
1166
1167                         return (LayoutKind)pos_values [0];
1168                 }
1169
1170                 public object GetParameterDefaultValue ()
1171                 {
1172                         return pos_values [0];
1173                 }
1174
1175                 public override bool Equals (object obj)
1176                 {
1177                         Attribute a = obj as Attribute;
1178                         if (a == null)
1179                                 return false;
1180
1181                         return Type == a.Type && Target == a.Target;
1182                 }
1183
1184                 public override int GetHashCode ()
1185                 {
1186                         return type.GetHashCode () ^ Target.GetHashCode ();
1187                 }
1188
1189                 /// <summary>
1190                 /// Emit attribute for Attributable symbol
1191                 /// </summary>
1192                 public void Emit (Dictionary<Attribute, List<Attribute>> allEmitted)
1193                 {
1194                         CustomAttributeBuilder cb = Resolve ();
1195                         if (cb == null)
1196                                 return;
1197
1198                         AttributeUsageAttribute usage_attr = GetAttributeUsage (Type);
1199                         if ((usage_attr.ValidOn & Target) == 0) {
1200                                 Report.Error (592, Location, "The attribute `{0}' is not valid on this declaration type. " +
1201                                               "It is valid on `{1}' declarations only",
1202                                         GetSignatureForError (), GetValidTargets ());
1203                                 return;
1204                         }
1205
1206                         var predefined = PredefinedAttributes.Get;
1207
1208                         try {
1209                                 foreach (Attributable target in targets)
1210                                         target.ApplyAttributeBuilder (this, cb, predefined);
1211                         } catch (Exception e) {
1212                                 Error_AttributeEmitError (e.Message);
1213                                 return;
1214                         }
1215
1216                         if (!usage_attr.AllowMultiple && allEmitted != null) {
1217                                 if (allEmitted.ContainsKey (this)) {
1218                                         var a = allEmitted [this];
1219                                         if (a == null) {
1220                                                 a = new List<Attribute> (2);
1221                                                 allEmitted [this] = a;
1222                                         }
1223                                         a.Add (this);
1224                                 } else {
1225                                         allEmitted.Add (this, null);
1226                                 }
1227                         }
1228
1229                         if (!RootContext.VerifyClsCompliance)
1230                                 return;
1231
1232                         // Here we are testing attribute arguments for array usage (error 3016)
1233                         if (Owner.IsClsComplianceRequired ()) {
1234                                 if (PosArguments != null)
1235                                         PosArguments.CheckArrayAsAttribute (context.Compiler);
1236
1237                                 if (NamedArguments == null)
1238                                         return;
1239
1240                                 NamedArguments.CheckArrayAsAttribute (context.Compiler);
1241                         }
1242                 }
1243
1244                 private Expression GetValue ()
1245                 {
1246                         if (PosArguments == null || PosArguments.Count < 1)
1247                                 return null;
1248
1249                         return PosArguments [0].Expr;
1250                 }
1251
1252                 public string GetString ()
1253                 {
1254                         Expression e = GetValue ();
1255                         if (e is StringConstant)
1256                                 return ((StringConstant)e).Value;
1257                         return null;
1258                 }
1259
1260                 public bool GetBoolean ()
1261                 {
1262                         Expression e = GetValue ();
1263                         if (e is BoolConstant)
1264                                 return ((BoolConstant)e).Value;
1265                         return false;
1266                 }
1267
1268                 public Type GetArgumentType ()
1269                 {
1270                         TypeOf e = GetValue () as TypeOf;
1271                         if (e == null)
1272                                 return null;
1273                         return e.TypeArgument;
1274                 }
1275
1276                 public override Expression CreateExpressionTree (ResolveContext ec)
1277                 {
1278                         throw new NotSupportedException ("ET");
1279                 }
1280
1281                 protected override Expression DoResolve (ResolveContext ec)
1282                 {
1283                         throw new NotImplementedException ();
1284                 }
1285
1286                 public override void Emit (EmitContext ec)
1287                 {
1288                         throw new NotImplementedException ();
1289                 }
1290         }
1291
1292
1293         /// <summary>
1294         /// For global attributes (assembly, module) we need special handling.
1295         /// Attributes can be located in the several files
1296         /// </summary>
1297         public class GlobalAttribute : Attribute
1298         {
1299                 public readonly NamespaceEntry ns;
1300
1301                 public GlobalAttribute (NamespaceEntry ns, string target, ATypeNameExpression expression,
1302                                         Arguments[] args, Location loc, bool nameEscaped):
1303                         base (target, expression, args, loc, nameEscaped)
1304                 {
1305                         this.ns = ns;
1306                 }
1307
1308                 public override void AttachTo (Attributable target, IMemberContext context)
1309                 {
1310                         if (ExplicitTarget == "assembly") {
1311                                 base.AttachTo (CodeGen.Assembly, context);
1312                                 return;
1313                         }
1314
1315                         if (ExplicitTarget == "module") {
1316                                 base.AttachTo (RootContext.ToplevelTypes, context);
1317                                 return;
1318                         }
1319
1320                         throw new NotImplementedException ("Unknown global explicit target " + ExplicitTarget);
1321                 }
1322
1323                 void Enter ()
1324                 {
1325                         // RootContext.ToplevelTypes has a single NamespaceEntry which gets overwritten
1326                         // each time a new file is parsed.  However, we need to use the NamespaceEntry
1327                         // in effect where the attribute was used.  Since code elsewhere cannot assume
1328                         // that the NamespaceEntry is right, just overwrite it.
1329                         //
1330                         // Precondition: RootContext.ToplevelTypes == null
1331
1332                         if (RootContext.ToplevelTypes.NamespaceEntry != null)
1333                                 throw new InternalErrorException (Location + " non-null NamespaceEntry");
1334
1335                         RootContext.ToplevelTypes.NamespaceEntry = ns;
1336                 }
1337
1338                 protected override bool IsSecurityActionValid (bool for_assembly)
1339                 {
1340                         return base.IsSecurityActionValid (true);
1341                 }
1342
1343                 void Leave ()
1344                 {
1345                         RootContext.ToplevelTypes.NamespaceEntry = null;
1346                 }
1347
1348                 protected override TypeExpr ResolveAsTypeTerminal (Expression expr, IMemberContext ec)
1349                 {
1350                         try {
1351                                 Enter ();
1352                                 return base.ResolveAsTypeTerminal (expr, ec);
1353                         }
1354                         finally {
1355                                 Leave ();
1356                         }
1357                 }
1358
1359                 protected override MethodSpec ResolveConstructor (ResolveContext ec)
1360                 {
1361                         try {
1362                                 Enter ();
1363                                 return base.ResolveConstructor (ec);
1364                         }
1365                         finally {
1366                                 Leave ();
1367                         }
1368                 }
1369
1370                 protected override bool ResolveNamedArguments (ResolveContext ec)
1371                 {
1372                         try {
1373                                 Enter ();
1374                                 return base.ResolveNamedArguments (ec);
1375                         }
1376                         finally {
1377                                 Leave ();
1378                         }
1379                 }
1380         }
1381
1382         public class Attributes {
1383                 public readonly List<Attribute> Attrs;
1384
1385                 public Attributes (Attribute a)
1386                 {
1387                         Attrs = new List<Attribute> ();
1388                         Attrs.Add (a);
1389                 }
1390
1391                 public Attributes (List<Attribute> attrs)
1392                 {
1393                         Attrs = attrs;
1394                 }
1395
1396                 public void AddAttributes (List<Attribute> attrs)
1397                 {
1398                         Attrs.AddRange (attrs);
1399                 }
1400
1401                 public void AttachTo (Attributable attributable, IMemberContext context)
1402                 {
1403                         foreach (Attribute a in Attrs)
1404                                 a.AttachTo (attributable, context);
1405                 }
1406
1407                 public Attributes Clone ()
1408                 {
1409                         var al = new List<Attribute> (Attrs.Count);
1410                         foreach (Attribute a in Attrs)
1411                                 al.Add (a.Clone ());
1412
1413                         return new Attributes (al);
1414                 }
1415
1416                 /// <summary>
1417                 /// Checks whether attribute target is valid for the current element
1418                 /// </summary>
1419                 public bool CheckTargets ()
1420                 {
1421                         foreach (Attribute a in Attrs) {
1422                                 if (!a.CheckTarget ())
1423                                         return false;
1424                         }
1425                         return true;
1426                 }
1427
1428                 public Attribute Search (PredefinedAttribute t)
1429                 {
1430                         foreach (Attribute a in Attrs) {
1431                                 if (a.ResolveType () == t)
1432                                         return a;
1433                         }
1434                         return null;
1435                 }
1436
1437                 /// <summary>
1438                 /// Returns all attributes of type 't'. Use it when attribute is AllowMultiple = true
1439                 /// </summary>
1440                 public Attribute[] SearchMulti (PredefinedAttribute t)
1441                 {
1442                         List<Attribute> ar = null;
1443
1444                         foreach (Attribute a in Attrs) {
1445                                 if (a.ResolveType () == t) {
1446                                         if (ar == null)
1447                                                 ar = new List<Attribute> (Attrs.Count);
1448                                         ar.Add (a);
1449                                 }
1450                         }
1451
1452                         return ar == null ? null : ar.ToArray ();
1453                 }
1454
1455                 public void Emit ()
1456                 {
1457                         CheckTargets ();
1458
1459                         Dictionary<Attribute, List<Attribute>> ld = Attrs.Count > 1 ? new Dictionary<Attribute, List<Attribute>> () : null;
1460
1461                         foreach (Attribute a in Attrs)
1462                                 a.Emit (ld);
1463
1464                         if (ld == null || ld.Count == 0)
1465                                 return;
1466
1467                         foreach (var d in ld) {
1468                                 if (d.Value == null)
1469                                         continue;
1470
1471                                 Attribute a = d.Key;
1472
1473                                 foreach (Attribute collision in d.Value)
1474                                         a.Report.SymbolRelatedToPreviousError (collision.Location, "");
1475
1476                                 a.Report.Error (579, a.Location, "The attribute `{0}' cannot be applied multiple times",
1477                                         a.GetSignatureForError ());
1478                         }
1479                 }
1480
1481                 public bool Contains (PredefinedAttribute t)
1482                 {
1483                         return Search (t) != null;
1484                 }
1485         }
1486
1487         /// <summary>
1488         /// Helper class for attribute verification routine.
1489         /// </summary>
1490         sealed class AttributeTester
1491         {
1492                 static Dictionary<Type, bool> analyzed_types;
1493                 static Dictionary<Type, ObsoleteAttribute> analyzed_types_obsolete;
1494                 static Dictionary<MemberInfo, ObsoleteAttribute> analyzed_member_obsolete;
1495                 static Dictionary<MethodBase, bool> analyzed_method_excluded;
1496 //              static Dictionary<FieldInfo, IFixedBuffer> fixed_buffer_cache;
1497
1498                 static AttributeTester ()
1499                 {
1500                         Reset ();
1501                 }
1502
1503                 private AttributeTester ()
1504                 {
1505                 }
1506
1507                 public static void Reset ()
1508                 {
1509                         analyzed_types = new Dictionary<Type, bool> (ReferenceEquality<Type>.Default);
1510                         analyzed_types_obsolete = new Dictionary<Type, ObsoleteAttribute> (ReferenceEquality<Type>.Default);
1511                         analyzed_member_obsolete = new Dictionary<MemberInfo, ObsoleteAttribute> (ReferenceEquality<MemberInfo>.Default);
1512                         analyzed_method_excluded = new Dictionary<MethodBase, bool> (ReferenceEquality<MethodBase>.Default);
1513 //                      fixed_buffer_cache = new Dictionary<FieldInfo, IFixedBuffer> (ReferenceEquality<FieldInfo>.Default);
1514                 }
1515
1516                 public enum Result {
1517                         Ok,
1518                         RefOutArrayError,
1519                         ArrayArrayError
1520                 }
1521
1522                 /// <summary>
1523                 /// Returns true if parameters of two compared methods are CLS-Compliant.
1524                 /// It tests differing only in ref or out, or in array rank.
1525                 /// </summary>
1526                 public static Result AreOverloadedMethodParamsClsCompliant (AParametersCollection pa, AParametersCollection pb)
1527                 {
1528                         Type [] types_a = pa.Types;
1529                         Type [] types_b = pb.Types;
1530                         if (types_a == null || types_b == null)
1531                                 return Result.Ok;
1532
1533                         if (types_a.Length != types_b.Length)
1534                                 return Result.Ok;
1535
1536                         Result result = Result.Ok;
1537                         for (int i = 0; i < types_b.Length; ++i) {
1538                                 Type aType = types_a [i];
1539                                 Type bType = types_b [i];
1540
1541                                 if (aType.IsArray && bType.IsArray) {
1542                                         Type a_el_type = TypeManager.GetElementType (aType);
1543                                         Type b_el_type = TypeManager.GetElementType (bType);
1544                                         if (aType.GetArrayRank () != bType.GetArrayRank () && a_el_type == b_el_type) {
1545                                                 result = Result.RefOutArrayError;
1546                                                 continue;
1547                                         }
1548
1549                                         if (a_el_type.IsArray || b_el_type.IsArray) {
1550                                                 result = Result.ArrayArrayError;
1551                                                 continue;
1552                                         }
1553                                 }
1554
1555                                 if (aType != bType)
1556                                         return Result.Ok;
1557
1558                                 const Parameter.Modifier out_ref_mod = (Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
1559                                 if ((pa.FixedParameters[i].ModFlags & out_ref_mod) != (pb.FixedParameters[i].ModFlags & out_ref_mod))
1560                                         result = Result.RefOutArrayError;
1561                         }
1562                         return result;
1563                 }
1564
1565                 /// <summary>
1566                 /// This method tests the CLS compliance of external types. It doesn't test type visibility.
1567                 /// </summary>
1568                 public static bool IsClsCompliant (Type type)
1569                 {
1570                         if (type == null)
1571                                 return true;
1572
1573                         bool result;
1574                         if (analyzed_types.TryGetValue (type, out result))
1575                                 return result;
1576
1577                         if (type.IsPointer) {
1578                                 analyzed_types.Add (type, false);
1579                                 return false;
1580                         }
1581
1582                         if (type.IsArray) {
1583                                 result = IsClsCompliant (TypeManager.GetElementType (type));
1584                         } else if (TypeManager.IsNullableType (type)) {
1585                                 result = IsClsCompliant (TypeManager.TypeToCoreType (TypeManager.GetTypeArguments (type) [0]));
1586                         } else {
1587                                 result = AnalyzeTypeCompliance (type);
1588                         }
1589                         analyzed_types.Add (type, result);
1590                         return result;
1591                 }
1592
1593                 public static void VerifyModulesClsCompliance (CompilerContext ctx)
1594                 {
1595                         Module[] modules = GlobalRootNamespace.Instance.Modules;
1596                         if (modules == null)
1597                                 return;
1598
1599                         // The first module is generated assembly
1600                         for (int i = 1; i < modules.Length; ++i) {
1601                                 Module module = modules [i];
1602                                 if (!GetClsCompliantAttributeValue (module, null)) {
1603                                         ctx.Report.Error (3013, "Added modules must be marked with the CLSCompliant attribute " +
1604                                                       "to match the assembly", module.Name);
1605                                         return;
1606                                 }
1607                         }
1608                 }
1609
1610                 public static Type GetImportedIgnoreCaseClsType (string name)
1611                 {
1612                         foreach (Assembly a in GlobalRootNamespace.Instance.Assemblies) {
1613                                 Type t = a.GetType (name, false, true);
1614                                 if (t == null)
1615                                         continue;
1616
1617                                 if (IsClsCompliant (t))
1618                                         return t;
1619                         }
1620                         return null;
1621                 }
1622
1623                 static bool GetClsCompliantAttributeValue (ICustomAttributeProvider attribute_provider, Assembly a)
1624                 {
1625                         PredefinedAttribute pa = PredefinedAttributes.Get.CLSCompliant;
1626                         if (!pa.IsDefined)
1627                                 return false;
1628
1629                         object[] cls_attr = attribute_provider.GetCustomAttributes (pa.Type, false);
1630                         if (cls_attr.Length == 0) {
1631                                 if (a == null)
1632                                         return false;
1633
1634                                 return GetClsCompliantAttributeValue (a, null);
1635                         }
1636
1637                         return ((CLSCompliantAttribute)cls_attr [0]).IsCompliant;
1638                 }
1639
1640                 static bool AnalyzeTypeCompliance (Type type)
1641                 {
1642                         type = TypeManager.DropGenericTypeArguments (type);
1643                         DeclSpace ds = TypeManager.LookupDeclSpace (type);
1644                         if (ds != null) {
1645                                 return ds.IsClsComplianceRequired ();
1646                         }
1647
1648                         if (TypeManager.IsGenericParameter (type))
1649                                 return true;
1650
1651                         return GetClsCompliantAttributeValue (type, type.Assembly);
1652                 }
1653
1654                 /// <summary>
1655                 /// Returns instance of ObsoleteAttribute when type is obsolete
1656                 /// </summary>
1657                 public static ObsoleteAttribute GetObsoleteAttribute (Type type)
1658                 {
1659                         ObsoleteAttribute result;
1660                         if (analyzed_types_obsolete.TryGetValue (type, out result))
1661                                 return result;
1662
1663                         if (TypeManager.HasElementType (type)) {
1664                                 result = GetObsoleteAttribute (TypeManager.GetElementType (type));
1665                         } else if (TypeManager.IsGenericParameter (type))
1666                                 result = null;  // TODO: throw new NotSupportedException ()
1667                         else if (TypeManager.IsGenericType (type) && !TypeManager.IsGenericTypeDefinition (type)) {
1668                                 return GetObsoleteAttribute (TypeManager.DropGenericTypeArguments (type));
1669                         } else {
1670                                 DeclSpace type_ds = TypeManager.LookupDeclSpace (type);
1671
1672                                 // Type is external, we can get attribute directly
1673                                 if (type_ds == null) {
1674                                         PredefinedAttribute pa = PredefinedAttributes.Get.Obsolete;
1675                                         if (pa.IsDefined) {
1676                                                 object[] attribute = type.GetCustomAttributes (pa.Type, false);
1677                                                 if (attribute.Length == 1)
1678                                                         result = (ObsoleteAttribute) attribute[0];
1679                                         }
1680                                 } else {
1681                                         result = type_ds.GetObsoleteAttribute ();
1682                                 }
1683                         }
1684
1685                         // Cannot use .Add because of corlib bootstrap
1686                         analyzed_types_obsolete [type] = result;
1687                         return result;
1688                 }
1689
1690                 /// <summary>
1691                 /// Returns instance of ObsoleteAttribute when method is obsolete
1692                 /// </summary>
1693                 public static ObsoleteAttribute GetMethodObsoleteAttribute (MethodBase mb)
1694                 {
1695                         IMethodData mc = TypeManager.GetMethod (mb);
1696                         if (mc != null)
1697                                 return mc.GetObsoleteAttribute ();
1698
1699                         // compiler generated methods are not registered by AddMethod
1700                         if (mb.DeclaringType is TypeBuilder)
1701                                 return null;
1702
1703                         MemberInfo mi = TypeManager.GetPropertyFromAccessor (mb);
1704                         if (mi != null)
1705                                 return GetMemberObsoleteAttribute (mi);
1706
1707                         mi = TypeManager.GetEventFromAccessor (mb);
1708                         if (mi != null)
1709                                 return GetMemberObsoleteAttribute (mi);
1710
1711                         return GetMemberObsoleteAttribute (mb);
1712                 }
1713
1714                 /// <summary>
1715                 /// Returns instance of ObsoleteAttribute when member is obsolete
1716                 /// </summary>
1717                 public static ObsoleteAttribute GetMemberObsoleteAttribute (MemberInfo mi)
1718                 {
1719                         ObsoleteAttribute oa;
1720                         if (analyzed_member_obsolete.TryGetValue (mi, out oa))
1721                                 return oa;
1722
1723                         if ((mi.DeclaringType is TypeBuilder) || TypeManager.IsGenericType (mi.DeclaringType))
1724                                 return null;
1725
1726                         PredefinedAttribute pa = PredefinedAttributes.Get.Obsolete;
1727                         if (!pa.IsDefined)
1728                                 return null;
1729
1730                         oa = System.Attribute.GetCustomAttribute (mi, pa.Type, false) as ObsoleteAttribute;
1731                         analyzed_member_obsolete.Add (mi, oa);
1732                         return oa;
1733                 }
1734
1735                 /// <summary>
1736                 /// Common method for Obsolete error/warning reporting.
1737                 /// </summary>
1738                 public static void Report_ObsoleteMessage (ObsoleteAttribute oa, string member, Location loc, Report Report)
1739                 {
1740                         if (oa.IsError) {
1741                                 Report.Error (619, loc, "`{0}' is obsolete: `{1}'", member, oa.Message);
1742                                 return;
1743                         }
1744
1745                         if (oa.Message == null || oa.Message.Length == 0) {
1746                                 Report.Warning (612, 1, loc, "`{0}' is obsolete", member);
1747                                 return;
1748                         }
1749                         Report.Warning (618, 2, loc, "`{0}' is obsolete: `{1}'", member, oa.Message);
1750                 }
1751
1752                 public static bool IsConditionalMethodExcluded (MethodBase mb, Location loc)
1753                 {
1754                         bool excluded;
1755                         if (analyzed_method_excluded.TryGetValue (mb, out excluded))
1756                                 return excluded;
1757
1758                         PredefinedAttribute pa = PredefinedAttributes.Get.Conditional;
1759                         if (!pa.IsDefined)
1760                                 return false;
1761
1762                         ConditionalAttribute[] attrs = mb.GetCustomAttributes (pa.Type, true)
1763                                 as ConditionalAttribute[];
1764                         if (attrs.Length == 0) {
1765                                 analyzed_method_excluded.Add (mb, false);
1766                                 return false;
1767                         }
1768
1769                         foreach (ConditionalAttribute a in attrs) {
1770                                 if (loc.CompilationUnit.IsConditionalDefined (a.ConditionString)) {
1771                                         analyzed_method_excluded.Add (mb, false);
1772                                         return false;
1773                                 }
1774                         }
1775
1776                         analyzed_method_excluded.Add (mb, true);
1777                         return true;
1778                 }
1779
1780                 /// <summary>
1781                 /// Analyzes class whether it has attribute which has ConditionalAttribute
1782                 /// and its condition is not defined.
1783                 /// </summary>
1784                 public static bool IsAttributeExcluded (Type type, Location loc)
1785                 {
1786                         if (!type.IsClass)
1787                                 return false;
1788
1789                         Class class_decl = TypeManager.LookupDeclSpace (type) as Class;
1790
1791                         // TODO: add caching
1792                         // TODO: merge all Type bases attribute caching to one cache to save memory
1793                         PredefinedAttribute pa = PredefinedAttributes.Get.Conditional;
1794                         if (class_decl == null && pa.IsDefined) {
1795                                 object[] attributes = type.GetCustomAttributes (pa.Type, false);
1796                                 foreach (ConditionalAttribute ca in attributes) {
1797                                         if (loc.CompilationUnit.IsConditionalDefined (ca.ConditionString))
1798                                                 return false;
1799                                 }
1800                                 return attributes.Length > 0;
1801                         }
1802
1803                         return class_decl.IsExcluded ();
1804                 }
1805
1806                 public static Type GetCoClassAttribute (Type type)
1807                 {
1808                         TypeContainer tc = TypeManager.LookupInterface (type);
1809                         PredefinedAttribute pa = PredefinedAttributes.Get.CoClass;
1810                         if (tc == null) {
1811                                 if (!pa.IsDefined)
1812                                         return null;
1813
1814                                 object[] o = type.GetCustomAttributes (pa.Type, false);
1815                                 if (o.Length < 1)
1816                                         return null;
1817                                 return ((System.Runtime.InteropServices.CoClassAttribute)o[0]).CoClass;
1818                         }
1819
1820                         if (tc.OptAttributes == null)
1821                                 return null;
1822
1823                         Attribute a = tc.OptAttributes.Search (pa);
1824                         if (a == null)
1825                                 return null;
1826
1827                         return a.GetCoClassAttributeValue ();
1828                 }
1829         }
1830
1831         public class PredefinedAttributes
1832         {
1833                 // Core types
1834                 public readonly PredefinedAttribute ParamArray;
1835                 public readonly PredefinedAttribute Out;
1836
1837                 // Optional types
1838                 public readonly PredefinedAttribute Obsolete;
1839                 public readonly PredefinedAttribute DllImport;
1840                 public readonly PredefinedAttribute MethodImpl;
1841                 public readonly PredefinedAttribute MarshalAs;
1842                 public readonly PredefinedAttribute In;
1843                 public readonly PredefinedAttribute IndexerName;
1844                 public readonly PredefinedAttribute Conditional;
1845                 public readonly PredefinedAttribute CLSCompliant;
1846                 public readonly PredefinedAttribute Security;
1847                 public readonly PredefinedAttribute Required;
1848                 public readonly PredefinedAttribute Guid;
1849                 public readonly PredefinedAttribute AssemblyCulture;
1850                 public readonly PredefinedAttribute AssemblyVersion;
1851                 public readonly PredefinedAttribute ComImport;
1852                 public readonly PredefinedAttribute CoClass;
1853                 public readonly PredefinedAttribute AttributeUsage;
1854                 public readonly PredefinedAttribute DefaultParameterValue;
1855                 public readonly PredefinedAttribute OptionalParameter;
1856
1857                 // New in .NET 2.0
1858                 public readonly PredefinedAttribute DefaultCharset;
1859                 public readonly PredefinedAttribute TypeForwarder;
1860                 public readonly PredefinedAttribute FixedBuffer;
1861                 public readonly PredefinedAttribute CompilerGenerated;
1862                 public readonly PredefinedAttribute InternalsVisibleTo;
1863                 public readonly PredefinedAttribute RuntimeCompatibility;
1864                 public readonly PredefinedAttribute DebuggerHidden;
1865                 public readonly PredefinedAttribute UnsafeValueType;
1866
1867                 // New in .NET 3.5
1868                 public readonly PredefinedAttribute Extension;
1869
1870                 // New in .NET 4.0
1871                 public readonly PredefinedAttribute Dynamic;
1872                 public readonly PredefinedAttribute DynamicTransform;   // DynamicAttribute with transform arguments
1873
1874                 //
1875                 // Optional types which are used as types and for member lookup
1876                 //
1877                 public readonly PredefinedAttribute DefaultMember;
1878                 public readonly PredefinedAttribute DecimalConstant;
1879                 public readonly PredefinedAttribute StructLayout;
1880                 public readonly PredefinedAttribute FieldOffset;
1881
1882                 public static PredefinedAttributes Get = new PredefinedAttributes ();
1883
1884                 private PredefinedAttributes ()
1885                 {
1886                         ParamArray = new PredefinedAttribute ("System", "ParamArrayAttribute");
1887                         Out = new PredefinedAttribute ("System.Runtime.InteropServices", "OutAttribute");
1888
1889                         Obsolete = new PredefinedAttribute ("System", "ObsoleteAttribute");
1890                         DllImport = new PredefinedAttribute ("System.Runtime.InteropServices", "DllImportAttribute");
1891                         MethodImpl = new PredefinedAttribute ("System.Runtime.CompilerServices", "MethodImplAttribute");
1892                         MarshalAs = new PredefinedAttribute ("System.Runtime.InteropServices", "MarshalAsAttribute");
1893                         In = new PredefinedAttribute ("System.Runtime.InteropServices", "InAttribute");
1894                         IndexerName = new PredefinedAttribute ("System.Runtime.CompilerServices", "IndexerNameAttribute");
1895                         Conditional = new PredefinedAttribute ("System.Diagnostics", "ConditionalAttribute");
1896                         CLSCompliant = new PredefinedAttribute ("System", "CLSCompliantAttribute");
1897                         Security = new PredefinedAttribute ("System.Security.Permissions", "SecurityAttribute");
1898                         Required = new PredefinedAttribute ("System.Runtime.CompilerServices", "RequiredAttributeAttribute");
1899                         Guid = new PredefinedAttribute ("System.Runtime.InteropServices", "GuidAttribute");
1900                         AssemblyCulture = new PredefinedAttribute ("System.Reflection", "AssemblyCultureAttribute");
1901                         AssemblyVersion = new PredefinedAttribute ("System.Reflection", "AssemblyVersionAttribute");
1902                         ComImport = new PredefinedAttribute ("System.Runtime.InteropServices", "ComImportAttribute");
1903                         CoClass = new PredefinedAttribute ("System.Runtime.InteropServices", "CoClassAttribute");
1904                         AttributeUsage = new PredefinedAttribute ("System", "AttributeUsageAttribute");
1905                         DefaultParameterValue = new PredefinedAttribute ("System.Runtime.InteropServices", "DefaultParameterValueAttribute");
1906                         OptionalParameter = new PredefinedAttribute ("System.Runtime.InteropServices", "OptionalAttribute");
1907
1908                         DefaultCharset = new PredefinedAttribute ("System.Runtime.InteropServices", "DefaultCharSetAttribute");
1909                         TypeForwarder = new PredefinedAttribute ("System.Runtime.CompilerServices", "TypeForwardedToAttribute");
1910                         FixedBuffer = new PredefinedAttribute ("System.Runtime.CompilerServices", "FixedBufferAttribute");
1911                         CompilerGenerated = new PredefinedAttribute ("System.Runtime.CompilerServices", "CompilerGeneratedAttribute");
1912                         InternalsVisibleTo = new PredefinedAttribute ("System.Runtime.CompilerServices", "InternalsVisibleToAttribute");
1913                         RuntimeCompatibility = new PredefinedAttribute ("System.Runtime.CompilerServices", "RuntimeCompatibilityAttribute");
1914                         DebuggerHidden = new PredefinedAttribute ("System.Diagnostics", "DebuggerHiddenAttribute");
1915                         UnsafeValueType = new PredefinedAttribute ("System.Runtime.CompilerServices", "UnsafeValueTypeAttribute");
1916
1917                         Extension = new PredefinedAttribute ("System.Runtime.CompilerServices", "ExtensionAttribute");
1918
1919                         Dynamic = new PredefinedAttribute ("System.Runtime.CompilerServices", "DynamicAttribute");
1920                         DynamicTransform = new PredefinedAttribute ("System.Runtime.CompilerServices", "DynamicAttribute");
1921
1922                         DefaultMember = new PredefinedAttribute ("System.Reflection", "DefaultMemberAttribute");
1923                         DecimalConstant = new PredefinedAttribute ("System.Runtime.CompilerServices", "DecimalConstantAttribute");
1924                         StructLayout = new PredefinedAttribute ("System.Runtime.InteropServices", "StructLayoutAttribute");
1925                         FieldOffset = new PredefinedAttribute ("System.Runtime.InteropServices", "FieldOffsetAttribute");
1926                 }
1927
1928                 public void Initialize (CompilerContext ctx)
1929                 {
1930                         foreach (FieldInfo fi in GetType ().GetFields (BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly)) {
1931                                 ((PredefinedAttribute) fi.GetValue (this)).Initialize (ctx, true);
1932                         }
1933                 }
1934
1935                 public static void Reset ()
1936                 {
1937                         Get = new PredefinedAttributes ();
1938                 }
1939         }
1940
1941         public class PredefinedAttribute
1942         {
1943                 Type type;
1944                 CustomAttributeBuilder cab;
1945                 ConstructorInfo ctor;
1946                 readonly string ns, name;
1947                 CompilerContext compiler;
1948
1949                 static readonly Type NotFound = typeof (PredefinedAttribute);
1950
1951                 public PredefinedAttribute (string ns, string name)
1952                 {
1953                         this.ns = ns;
1954                         this.name = name;
1955                 }
1956
1957                 public static bool operator == (Type type, PredefinedAttribute pa)
1958                 {
1959                         return type == pa.type;
1960                 }
1961
1962                 public static bool operator != (Type type, PredefinedAttribute pa)
1963                 {
1964                         return type != pa.type;
1965                 }
1966
1967                 public ConstructorInfo Constructor {
1968                         get { return ctor; }
1969                 }
1970
1971                 public override int GetHashCode ()
1972                 {
1973                         return base.GetHashCode ();
1974                 }
1975
1976                 public string GetSignatureForError ()
1977                 {
1978                         return ns + "." + name;
1979                 }
1980
1981                 public override bool Equals (object obj)
1982                 {
1983                         throw new NotSupportedException ();
1984                 }
1985
1986                 public void EmitAttribute (ConstructorBuilder builder)
1987                 {
1988                         if (ResolveBuilder ())
1989                                 builder.SetCustomAttribute (cab);
1990                 }
1991
1992                 public void EmitAttribute (MethodBuilder builder)
1993                 {
1994                         if (ResolveBuilder ())
1995                                 builder.SetCustomAttribute (cab);
1996                 }
1997
1998                 public void EmitAttribute (PropertyBuilder builder)
1999                 {
2000                         if (ResolveBuilder ())
2001                                 builder.SetCustomAttribute (cab);
2002                 }
2003
2004                 public void EmitAttribute (FieldBuilder builder)
2005                 {
2006                         if (ResolveBuilder ())
2007                                 builder.SetCustomAttribute (cab);
2008                 }
2009
2010                 public void EmitAttribute (TypeBuilder builder)
2011                 {
2012                         if (ResolveBuilder ())
2013                                 builder.SetCustomAttribute (cab);
2014                 }
2015
2016                 public void EmitAttribute (AssemblyBuilder builder)
2017                 {
2018                         if (ResolveBuilder ())
2019                                 builder.SetCustomAttribute (cab);
2020                 }
2021
2022                 public void EmitAttribute (ParameterBuilder builder)
2023                 {
2024                         if (ResolveBuilder ())
2025                                 builder.SetCustomAttribute (cab);
2026                 }
2027
2028                 public bool IsDefined {
2029                         get { return type != null && type != NotFound; }
2030                 }
2031
2032                 public void Initialize (CompilerContext ctx, bool canFail)
2033                 {
2034                         this.compiler = ctx;
2035                         Resolve (canFail);
2036                 }
2037
2038                 public bool Resolve (bool canFail)
2039                 {
2040                         if (type != null) {
2041                                 if (IsDefined)
2042                                         return true;
2043                                 if (canFail)
2044                                         return false;
2045                         }
2046
2047                         type = TypeManager.CoreLookupType (compiler, ns, name, MemberKind.Class, !canFail);
2048                         if (type == null) {
2049                                 type = NotFound;
2050                                 return false;
2051                         }
2052
2053                         return true;
2054                 }
2055
2056                 bool ResolveBuilder ()
2057                 {
2058                         if (cab != null)
2059                                 return true;
2060
2061                         //
2062                         // Handle all parameter-less attributes as optional
2063                         //
2064                         if (!Resolve (true))
2065                                 return false;
2066
2067                         ConstructorInfo ci = TypeManager.GetPredefinedConstructor (type, Location.Null, Type.EmptyTypes);
2068                         if (ci == null)
2069                                 return false;
2070
2071                         cab = new CustomAttributeBuilder (ci, new object[0]);
2072                         return true;
2073                 }
2074
2075                 public bool ResolveConstructor (Location loc, params Type[] argType)
2076                 {
2077                         if (ctor != null)
2078                                 throw new InternalErrorException ("Predefined ctor redefined");
2079
2080                         if (!Resolve (false))
2081                                 return false;
2082
2083                         ctor = TypeManager.GetPredefinedConstructor (type, loc, argType);
2084                         return ctor != null;
2085                 }
2086
2087                 public Type Type {
2088                         get { return type; }
2089                 }
2090         }
2091 }