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;
  16 using System.Collections.Specialized;
  17 using System.Reflection;
  18 using System.Reflection.Emit;
  19 using System.Runtime.InteropServices;
  20 using System.Runtime.CompilerServices;
  21 using System.Security;
  22 using System.Security.Permissions;
  23 using System.Text;
  24 using System.IO;
  25
  26 namespace Mono.CSharp {
  27
  28         /// <summary>
  29         ///   Base class for objects that can have Attributes applied to them.
  30         /// </summary>
  31         public abstract class Attributable {
  32                 /// <summary>
  33                 ///   Attributes for this type
  34                 /// </summary>
  35                 protected Attributes attributes;
  36
  37                 public Attributable (Attributes attrs)
  38                 {
  39                         if (attrs != null)
  40                                 OptAttributes = attrs;
  41                 }
  42
  43                 public Attributes OptAttributes
  44                 {
  45                         get {
  46                                 return attributes;
  47                         }
  48                         set {
  49                                 attributes = value;
  50
  51                                 if (attributes != null) {
  52                                         attributes.AttachTo (this);
  53                                 }
  54                         }
  55                 }
  56
  57                 /// <summary>
  58                 /// Use member-specific procedure to apply attribute @a in @cb to the entity being built in @builder
  59                 /// </summary>
  60                 public abstract void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb);
  61
  62                 /// <summary>
  63                 /// Returns one AttributeTarget for this element.
  64                 /// </summary>
  65                 public abstract AttributeTargets AttributeTargets { get; }
  66
  67                 public abstract IResolveContext ResolveContext { get; }
  68
  69                 public abstract bool IsClsComplianceRequired ();
  70
  71                 /// <summary>
  72                 /// Gets list of valid attribute targets for explicit target declaration.
  73                 /// The first array item is default target. Don't break this rule.
  74                 /// </summary>
  75                 public abstract string[] ValidAttributeTargets { get; }
  76         };
  77
  78         public class Attribute : Expression
  79         {
  80                 public readonly string ExplicitTarget;
  81                 public AttributeTargets Target;
  82
  83                 // TODO: remove this member
  84                 public readonly string    Name;
  85                 public readonly Expression LeftExpr;
  86                 public readonly string Identifier;
  87
  88                 ArrayList PosArguments;
  89                 ArrayList NamedArguments;
  90
  91                 bool resolve_error;
  92                 readonly bool nameEscaped;
  93
  94                 // It can contain more onwers when the attribute is applied to multiple fiels.
  95                 protected Attributable[] owners;
  96
  97                 static readonly AttributeUsageAttribute DefaultUsageAttribute = new AttributeUsageAttribute (AttributeTargets.All);
  98                 static Assembly orig_sec_assembly;
  99                 public static readonly object[] EmptyObject = new object [0];
 100
 101                 // non-null if named args present after Resolve () is called
 102                 PropertyInfo [] prop_info_arr;
 103                 FieldInfo [] field_info_arr;
 104                 object [] field_values_arr;
 105                 object [] prop_values_arr;
 106                 object [] pos_values;
 107
 108                 static PtrHashtable usage_attr_cache;
 109                 // Cache for parameter-less attributes
 110                 static PtrHashtable att_cache;
 111
 112                 public Attribute (string target, Expression left_expr, string identifier, object[] args, Location loc, bool nameEscaped)
 113                 {
 114                         LeftExpr = left_expr;
 115                         Identifier = identifier;
 116                         Name = LeftExpr == null ? identifier : LeftExpr + "." + identifier;
 117                         if (args != null) {
 118                                 PosArguments = (ArrayList)args [0];
 119                                 NamedArguments = (ArrayList)args [1];
 120                         }
 121                         this.loc = loc;
 122                         ExplicitTarget = target;
 123                         this.nameEscaped = nameEscaped;
 124                 }
 125
 126                 public Attribute Clone ()
 127                 {
 128                         Attribute a = new Attribute (ExplicitTarget, LeftExpr, Identifier, null, loc, nameEscaped);
 129                         a.PosArguments = PosArguments;
 130                         a.NamedArguments = NamedArguments;
 131                         return a;
 132                 }
 133
 134                 static Attribute ()
 135                 {
 136                         Reset ();
 137                 }
 138
 139                 public static void Reset ()
 140                 {
 141                         usage_attr_cache = new PtrHashtable ();
 142                         att_cache = new PtrHashtable ();
 143                 }
 144
 145                 public virtual void AttachTo (Attributable owner)
 146                 {
 147                         if (this.owners == null) {
 148                                 this.owners = new Attributable[1] { owner };
 149                                 return;
 150                         }
 151
 152                         // When the same attribute is attached to multiple fiels
 153                         // we use this extra_owners as a list of owners. The attribute
 154                         // then can be removed because will be emitted when first owner
 155                         // is served
 156                         Attributable[] new_array = new Attributable [this.owners.Length + 1];
 157                         owners.CopyTo (new_array, 0);
 158                         new_array [owners.Length] = owner;
 159                         this.owners = new_array;
 160                         owner.OptAttributes = null;
 161                 }
 162
 163                 void Error_InvalidNamedArgument (string name)
 164                 {
 165                         Report.Error (617, Location, "`{0}' is not a valid named attribute argument. Named attribute arguments " +
 166                                       "must be fields which are not readonly, static, const or read-write properties which are " +
 167                                       "public and not static",
 168                               name);
 169                 }
 170
 171                 void Error_InvalidNamedAgrumentType (string name)
 172                 {
 173                         Report.Error (655, Location, "`{0}' is not a valid named attribute argument because it is not a valid " +
 174                                       "attribute parameter type", name);
 175                 }
 176
 177                 public static void Error_AttributeArgumentNotValid (Location loc)
 178                 {
 179                         Report.Error (182, loc,
 180                                       "An attribute argument must be a constant expression, typeof " +
 181                                       "expression or array creation expression");
 182                 }
 183
 184                 static void Error_TypeParameterInAttribute (Location loc)
 185                 {
 186                         Report.Error (
 187                                 -202, loc, "Can not use a type parameter in an attribute");
 188                 }
 189
 190                 public void Error_MissingGuidAttribute ()
 191                 {
 192                         Report.Error (596, Location, "The Guid attribute must be specified with the ComImport attribute");
 193                 }
 194
 195                 public void Error_MisusedExtensionAttribute ()
 196                 {
 197                         Report.Error (1112, Location, "Do not use `{0}' directly. Use parameter modifier `this' instead", GetSignatureForError ());
 198                 }
 199
 200                 /// <summary>
 201                 /// This is rather hack. We report many emit attribute error with same error to be compatible with
 202                 /// csc. But because csc has to report them this way because error came from ilasm we needn't.
 203                 /// </summary>
 204                 public void Error_AttributeEmitError (string inner)
 205                 {
 206                         Report.Error (647, Location, "Error during emitting `{0}' attribute. The reason is `{1}'",
 207                                       TypeManager.CSharpName (Type), inner);
 208                 }
 209
 210                 public void Error_InvalidSecurityParent ()
 211                 {
 212                         Error_AttributeEmitError ("it is attached to invalid parent");
 213                 }
 214
 215                 Attributable Owner {
 216                         get {
 217                                 return owners [0];
 218                         }
 219                 }
 220
 221                 protected virtual TypeExpr ResolveAsTypeTerminal (Expression expr, IResolveContext ec, bool silent)
 222                 {
 223                         return expr.ResolveAsTypeTerminal (ec, silent);
 224                 }
 225
 226                 Type ResolvePossibleAttributeType (string name, bool silent, ref bool is_attr)
 227                 {
 228                         IResolveContext rc = Owner.ResolveContext;
 229
 230                         TypeExpr te;
 231                         if (LeftExpr == null) {
 232                                 te = ResolveAsTypeTerminal (new SimpleName (name, Location), rc, silent);
 233                         } else {
 234                                 te = ResolveAsTypeTerminal (new MemberAccess (LeftExpr, name), rc, silent);
 235                         }
 236
 237                         if (te == null)
 238                                 return null;
 239
 240                         Type t = te.Type;
 241                         if (TypeManager.IsSubclassOf (t, TypeManager.attribute_type)) {
 242                                 is_attr = true;
 243                         } else if (!silent) {
 244                                 Report.SymbolRelatedToPreviousError (t);
 245                                 Report.Error (616, Location, "`{0}': is not an attribute class", TypeManager.CSharpName (t));
 246                         }
 247                         return t;
 248                 }
 249
 250                 /// <summary>
 251                 ///   Tries to resolve the type of the attribute. Flags an error if it can't, and complain is true.
 252                 /// </summary>
 253                 void ResolveAttributeType ()
 254                 {
 255                         bool t1_is_attr = false;
 256                         Type t1 = ResolvePossibleAttributeType (Identifier, true, ref t1_is_attr);
 257
 258                         bool t2_is_attr = false;
 259                         Type t2 = nameEscaped ? null :
 260                                 ResolvePossibleAttributeType (Identifier + "Attribute", true, ref t2_is_attr);
 261
 262                         if (t1_is_attr && t2_is_attr) {
 263                                 Report.Error (1614, Location, "`{0}' is ambiguous between `{0}' and `{0}Attribute'. " +
 264                                               "Use either `@{0}' or `{0}Attribute'", GetSignatureForError ());
 265                                 resolve_error = true;
 266                                 return;
 267                         }
 268
 269                         if (t1_is_attr) {
 270                                 Type = t1;
 271                                 return;
 272                         }
 273
 274                         if (t2_is_attr) {
 275                                 Type = t2;
 276                                 return;
 277                         }
 278
 279                         if (t1 == null && t2 == null)
 280                                 ResolvePossibleAttributeType (Identifier, false, ref t1_is_attr);
 281                         if (t1 != null)
 282                                 ResolvePossibleAttributeType (Identifier, false, ref t1_is_attr);
 283                         if (t2 != null)
 284                                 ResolvePossibleAttributeType (Identifier + "Attribute", false, ref t2_is_attr);
 285
 286                         resolve_error = true;
 287                 }
 288
 289                 public virtual Type ResolveType ()
 290                 {
 291                         if (Type == null && !resolve_error)
 292                                 ResolveAttributeType ();
 293                         return Type;
 294                 }
 295
 296                 public override string GetSignatureForError ()
 297                 {
 298                         if (Type != null)
 299                                 return TypeManager.CSharpName (Type);
 300
 301                         return LeftExpr == null ? Identifier : LeftExpr.GetSignatureForError () + "." + Identifier;
 302                 }
 303
 304                 public bool HasSecurityAttribute {
 305                         get {
 306                                 return TypeManager.security_attr_type != null &&
 307                                 TypeManager.IsSubclassOf (type, TypeManager.security_attr_type);
 308                         }
 309                 }
 310
 311                 public bool IsValidSecurityAttribute ()
 312                 {
 313                         return HasSecurityAttribute && IsSecurityActionValid (false);
 314                 }
 315
 316                 static bool IsValidArgumentType (Type t)
 317                 {
 318                         if (t.IsArray)
 319                                 t = TypeManager.GetElementType (t);
 320
 321                         return t == TypeManager.string_type ||
 322                                 TypeManager.IsPrimitiveType (t) ||
 323                                 TypeManager.IsEnumType (t) ||
 324                                 t == TypeManager.object_type ||
 325                                 t == TypeManager.type_type;
 326                 }
 327
 328                 [Conditional ("GMCS_SOURCE")]
 329                 void ApplyModuleCharSet ()
 330                 {
 331                         if (Type != TypeManager.dllimport_type)
 332                                 return;
 333
 334                         if (!CodeGen.Module.HasDefaultCharSet)
 335                                 return;
 336
 337                         const string CharSetEnumMember = "CharSet";
 338                         if (NamedArguments == null) {
 339                                 NamedArguments = new ArrayList (1);
 340                         } else {
 341                                 foreach (DictionaryEntry de in NamedArguments) {
 342                                         if ((string)de.Key == CharSetEnumMember)
 343                                                 return;
 344                                 }
 345                         }
 346
 347                         NamedArguments.Add (new DictionaryEntry (CharSetEnumMember,
 348                                 new Argument (Constant.CreateConstant (typeof (CharSet), CodeGen.Module.DefaultCharSet, Location))));
 349                 }
 350
 351                 public CustomAttributeBuilder Resolve ()
 352                 {
 353                         if (resolve_error)
 354                                 return null;
 355
 356                         resolve_error = true;
 357
 358                         if (Type == null) {
 359                                 ResolveAttributeType ();
 360                                 if (Type == null)
 361                                         return null;
 362                         }
 363
 364                         if (Type.IsAbstract) {
 365                                 Report.Error (653, Location, "Cannot apply attribute class `{0}' because it is abstract", GetSignatureForError ());
 366                                 return null;
 367                         }
 368
 369                         ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (Type);
 370                         if (obsolete_attr != null) {
 371                                 AttributeTester.Report_ObsoleteMessage (obsolete_attr, TypeManager.CSharpName (Type), Location);
 372                         }
 373
 374                         if (PosArguments == null && NamedArguments == null) {
 375                                 object o = att_cache [Type];
 376                                 if (o != null) {
 377                                         resolve_error = false;
 378                                         return (CustomAttributeBuilder)o;
 379                                 }
 380                         }
 381
 382                         Attributable owner = Owner;
 383                         DeclSpace ds = owner.ResolveContext as DeclSpace;
 384                         if (ds == null)
 385                                 ds = owner.ResolveContext.DeclContainer;
 386
 387                         EmitContext ec = new EmitContext (owner.ResolveContext, ds, owner.ResolveContext.DeclContainer,
 388                                 Location, null, typeof (Attribute), owner.ResolveContext.DeclContainer.ModFlags, false);
 389                         ec.IsAnonymousMethodAllowed = false;
 390
 391                         ConstructorInfo ctor = ResolveConstructor (ec);
 392                         if (ctor == null) {
 393                                 if (Type is TypeBuilder &&
 394                                     TypeManager.LookupDeclSpace (Type).MemberCache == null)
 395                                         // The attribute type has been DefineType'd, but not Defined.  Let's not treat it as an error.
 396                                         // It'll be resolved again when the attached-to entity is emitted.
 397                                         resolve_error = false;
 398                                 return null;
 399                         }
 400
 401                         ApplyModuleCharSet ();
 402
 403                         CustomAttributeBuilder cb;
 404                         try {
 405                                 // SRE does not allow private ctor but we want to report all source code errors
 406                                 if (ctor.IsPrivate)
 407                                         return null;
 408
 409                                 if (NamedArguments == null) {
 410                                         cb = new CustomAttributeBuilder (ctor, pos_values);
 411
 412                                         if (pos_values.Length == 0)
 413                                                 att_cache.Add (Type, cb);
 414
 415                                         resolve_error = false;
 416                                         return cb;
 417                                 }
 418
 419                                 if (!ResolveNamedArguments (ec)) {
 420                                         return null;
 421                                 }
 422
 423                                 cb = new CustomAttributeBuilder (ctor, pos_values,
 424                                                 prop_info_arr, prop_values_arr,
 425                                                 field_info_arr, field_values_arr);
 426
 427                                 resolve_error = false;
 428                                 return cb;
 429                         }
 430                         catch (Exception) {
 431                                 Error_AttributeArgumentNotValid (Location);
 432                                 return null;
 433                         }
 434                 }
 435
 436                 protected virtual ConstructorInfo ResolveConstructor (EmitContext ec)
 437                 {
 438                         if (PosArguments != null) {
 439                                 for (int i = 0; i < PosArguments.Count; i++) {
 440                                         Argument a = (Argument) PosArguments [i];
 441
 442                                         if (!a.Resolve (ec, Location))
 443                                                 return null;
 444                                 }
 445                         }
 446
 447                         MethodGroupExpr mg = MemberLookupFinal (ec, ec.ContainerType,
 448                                 Type, ".ctor", MemberTypes.Constructor,
 449                                 BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly,
 450                                 Location) as MethodGroupExpr;
 451
 452                         if (mg == null)
 453                                 return null;
 454
 455                         mg = mg.OverloadResolve (ec, ref PosArguments, false, Location);
 456                         if (mg == null)
 457                                 return null;
 458
 459                         ConstructorInfo constructor = (ConstructorInfo)mg;
 460                         if (PosArguments == null) {
 461                                 pos_values = EmptyObject;
 462                                 return constructor;
 463                         }
 464
 465                         AParametersCollection pd = TypeManager.GetParameterData (constructor);
 466
 467                         int pos_arg_count = PosArguments.Count;
 468                         pos_values = new object [pos_arg_count];
 469                         for (int j = 0; j < pos_arg_count; ++j) {
 470                                 Argument a = (Argument) PosArguments [j];
 471
 472                                 if (!a.Expr.GetAttributableValue (ec, a.Type, out pos_values [j]))
 473                                         return null;
 474                         }
 475
 476                         // Here we do the checks which should be done by corlib or by runtime.
 477                         // However Zoltan doesn't like it and every Mono compiler has to do it again.
 478
 479                         if (Type == TypeManager.guid_attr_type) {
 480                                 try {
 481                                         new Guid ((string)pos_values [0]);
 482                                 }
 483                                 catch (Exception e) {
 484                                         Error_AttributeEmitError (e.Message);
 485                                         return null;
 486                                 }
 487                         }
 488
 489                         if (Type == TypeManager.attribute_usage_type && (int)pos_values [0] == 0) {
 490                                 Report.Error (591, Location, "Invalid value for argument to `System.AttributeUsage' attribute");
 491                                 return null;
 492                         }
 493
 494                         if (Type == TypeManager.indexer_name_type || Type == TypeManager.conditional_attribute_type) {
 495                                 string v = pos_values [0] as string;
 496                                 if (!Tokenizer.IsValidIdentifier (v) || Tokenizer.IsKeyword (v)) {
 497                                         Report.Error (633, ((Argument)PosArguments[0]).Expr.Location,
 498                                                 "The argument to the `{0}' attribute must be a valid identifier", GetSignatureForError ());
 499                                         return null;
 500                                 }
 501                         }
 502
 503                         if (Type == TypeManager.methodimpl_attr_type && pos_values.Length == 1 &&
 504                                 pd.Types [0] == TypeManager.short_type &&
 505                                 !System.Enum.IsDefined (typeof (MethodImplOptions), pos_values [0].ToString ())) {
 506                                 Error_AttributeEmitError ("Incorrect argument value.");
 507                                 return null;
 508                         }
 509
 510                         return constructor;
 511                 }
 512
 513                 protected virtual bool ResolveNamedArguments (EmitContext ec)
 514                 {
 515                         int named_arg_count = NamedArguments.Count;
 516
 517                         ArrayList field_infos = new ArrayList (named_arg_count);
 518                         ArrayList prop_infos  = new ArrayList (named_arg_count);
 519                         ArrayList field_values = new ArrayList (named_arg_count);
 520                         ArrayList prop_values = new ArrayList (named_arg_count);
 521
 522                         ArrayList seen_names = new ArrayList(named_arg_count);
 523
 524                         foreach (DictionaryEntry de in NamedArguments) {
 525                                 string member_name = (string) de.Key;
 526
 527                                 if (seen_names.Contains(member_name)) {
 528                                         Report.Error(643, Location, "'{0}' duplicate named attribute argument", member_name);
 529                                         return false;
 530                                 }
 531                                 seen_names.Add(member_name);
 532
 533                                 Argument a = (Argument) de.Value;
 534                                 if (!a.Resolve (ec, Location))
 535                                         return false;
 536
 537                                 Expression member = Expression.MemberLookup (
 538                                         ec.ContainerType, Type, member_name,
 539                                         MemberTypes.Field | MemberTypes.Property,
 540                                         BindingFlags.Public | BindingFlags.Instance,
 541                                         Location);
 542
 543                                 if (member == null) {
 544                                         member = Expression.MemberLookup (ec.ContainerType, Type, member_name,
 545                                                 MemberTypes.Field | MemberTypes.Property, BindingFlags.NonPublic | BindingFlags.Instance,
 546                                                 Location);
 547
 548                                         if (member != null) {
 549                                                 Report.SymbolRelatedToPreviousError (member.Type);
 550                                                 Expression.ErrorIsInaccesible (Location, member.GetSignatureForError ());
 551                                                 return false;
 552                                         }
 553                                 }
 554
 555                                 if (member == null){
 556                                         Expression.Error_TypeDoesNotContainDefinition (Location, Type, member_name);
 557                                         return false;
 558                                 }
 559
 560                                 if (!(member is PropertyExpr || member is FieldExpr)) {
 561                                         Error_InvalidNamedArgument (member_name);
 562                                         return false;
 563                                 }
 564
 565                                 if (a.Expr is TypeParameterExpr){
 566                                         Error_TypeParameterInAttribute (Location);
 567                                         return false;
 568                                 }
 569
 570                                 ObsoleteAttribute obsolete_attr;
 571
 572                                 if (member is PropertyExpr) {
 573                                         PropertyInfo pi = ((PropertyExpr) member).PropertyInfo;
 574
 575                                         if (!pi.CanWrite || !pi.CanRead) {
 576                                                 Report.SymbolRelatedToPreviousError (pi);
 577                                                 Error_InvalidNamedArgument (member_name);
 578                                                 return false;
 579                                         }
 580
 581                                         if (!IsValidArgumentType (member.Type)) {
 582                                                 Report.SymbolRelatedToPreviousError (pi);
 583                                                 Error_InvalidNamedAgrumentType (member_name);
 584                                                 return false;
 585                                         }
 586
 587                                         object value;
 588                                         if (!a.Expr.GetAttributableValue (ec, member.Type, out value))
 589                                                 return false;
 590
 591                                         PropertyBase pb = TypeManager.GetProperty (pi);
 592                                         if (pb != null)
 593                                                 obsolete_attr = pb.GetObsoleteAttribute ();
 594                                         else
 595                                                 obsolete_attr = AttributeTester.GetMemberObsoleteAttribute (pi);
 596
 597                                         prop_values.Add (value);
 598                                         prop_infos.Add (pi);
 599
 600                                 } else {
 601                                         FieldInfo fi = ((FieldExpr) member).FieldInfo;
 602
 603                                         if (fi.IsInitOnly) {
 604                                                 Error_InvalidNamedArgument (member_name);
 605                                                 return false;
 606                                         }
 607
 608                                         if (!IsValidArgumentType (member.Type)) {
 609                                                 Report.SymbolRelatedToPreviousError (fi);
 610                                                 Error_InvalidNamedAgrumentType (member_name);
 611                                                 return false;
 612                                         }
 613
 614                                         object value;
 615                                         if (!a.Expr.GetAttributableValue (ec, member.Type, out value))
 616                                                 return false;
 617
 618                                         FieldBase fb = TypeManager.GetField (fi);
 619                                         if (fb != null)
 620                                                 obsolete_attr = fb.GetObsoleteAttribute ();
 621                                         else
 622                                                 obsolete_attr = AttributeTester.GetMemberObsoleteAttribute (fi);
 623
 624                                         field_values.Add (value);
 625                                         field_infos.Add (fi);
 626                                 }
 627
 628                                 if (obsolete_attr != null && !Owner.ResolveContext.IsInObsoleteScope)
 629                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, member.GetSignatureForError (), member.Location);
 630                         }
 631
 632                         prop_info_arr = new PropertyInfo [prop_infos.Count];
 633                         field_info_arr = new FieldInfo [field_infos.Count];
 634                         field_values_arr = new object [field_values.Count];
 635                         prop_values_arr = new object [prop_values.Count];
 636
 637                         field_infos.CopyTo  (field_info_arr, 0);
 638                         field_values.CopyTo (field_values_arr, 0);
 639
 640                         prop_values.CopyTo  (prop_values_arr, 0);
 641                         prop_infos.CopyTo   (prop_info_arr, 0);
 642
 643                         return true;
 644                 }
 645
 646                 /// <summary>
 647                 ///   Get a string containing a list of valid targets for the attribute 'attr'
 648                 /// </summary>
 649                 public string GetValidTargets ()
 650                 {
 651                         StringBuilder sb = new StringBuilder ();
 652                         AttributeTargets targets = GetAttributeUsage (Type).ValidOn;
 653
 654                         if ((targets & AttributeTargets.Assembly) != 0)
 655                                 sb.Append ("assembly, ");
 656
 657                         if ((targets & AttributeTargets.Module) != 0)
 658                                 sb.Append ("module, ");
 659
 660                         if ((targets & AttributeTargets.Class) != 0)
 661                                 sb.Append ("class, ");
 662
 663                         if ((targets & AttributeTargets.Struct) != 0)
 664                                 sb.Append ("struct, ");
 665
 666                         if ((targets & AttributeTargets.Enum) != 0)
 667                                 sb.Append ("enum, ");
 668
 669                         if ((targets & AttributeTargets.Constructor) != 0)
 670                                 sb.Append ("constructor, ");
 671
 672                         if ((targets & AttributeTargets.Method) != 0)
 673                                 sb.Append ("method, ");
 674
 675                         if ((targets & AttributeTargets.Property) != 0)
 676                                 sb.Append ("property, indexer, ");
 677
 678                         if ((targets & AttributeTargets.Field) != 0)
 679                                 sb.Append ("field, ");
 680
 681                         if ((targets & AttributeTargets.Event) != 0)
 682                                 sb.Append ("event, ");
 683
 684                         if ((targets & AttributeTargets.Interface) != 0)
 685                                 sb.Append ("interface, ");
 686
 687                         if ((targets & AttributeTargets.Parameter) != 0)
 688                                 sb.Append ("parameter, ");
 689
 690                         if ((targets & AttributeTargets.Delegate) != 0)
 691                                 sb.Append ("delegate, ");
 692
 693                         if ((targets & AttributeTargets.ReturnValue) != 0)
 694                                 sb.Append ("return, ");
 695
 696 #if NET_2_0
 697                         if ((targets & AttributeTargets.GenericParameter) != 0)
 698                                 sb.Append ("type parameter, ");
 699 #endif
 700                         return sb.Remove (sb.Length - 2, 2).ToString ();
 701                 }
 702
 703                 /// <summary>
 704                 /// Returns AttributeUsage attribute based on types hierarchy
 705                 /// </summary>
 706                 static AttributeUsageAttribute GetAttributeUsage (Type type)
 707                 {
 708                         AttributeUsageAttribute ua = usage_attr_cache [type] as AttributeUsageAttribute;
 709                         if (ua != null)
 710                                 return ua;
 711
 712                         Class attr_class = TypeManager.LookupClass (type);
 713
 714                         if (attr_class == null) {
 715                                 object[] usage_attr = type.GetCustomAttributes (TypeManager.attribute_usage_type, true);
 716                                 ua = (AttributeUsageAttribute)usage_attr [0];
 717                                 usage_attr_cache.Add (type, ua);
 718                                 return ua;
 719                         }
 720
 721                         Attribute a = null;
 722                         if (attr_class.OptAttributes != null)
 723                                 a = attr_class.OptAttributes.Search (TypeManager.attribute_usage_type);
 724
 725                         if (a == null) {
 726                                 if (attr_class.TypeBuilder.BaseType != TypeManager.attribute_type)
 727                                         ua = GetAttributeUsage (attr_class.TypeBuilder.BaseType);
 728                                 else
 729                                         ua = DefaultUsageAttribute;
 730                         } else {
 731                                 ua = a.GetAttributeUsageAttribute ();
 732                         }
 733
 734                         usage_attr_cache.Add (type, ua);
 735                         return ua;
 736                 }
 737
 738                 AttributeUsageAttribute GetAttributeUsageAttribute ()
 739                 {
 740                         if (pos_values == null)
 741                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 742                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 743                                 Resolve ();
 744
 745                         if (resolve_error)
 746                                 return DefaultUsageAttribute;
 747
 748                         AttributeUsageAttribute usage_attribute = new AttributeUsageAttribute ((AttributeTargets)pos_values [0]);
 749
 750                         object field = GetPropertyValue ("AllowMultiple");
 751                         if (field != null)
 752                                 usage_attribute.AllowMultiple = (bool)field;
 753
 754                         field = GetPropertyValue ("Inherited");
 755                         if (field != null)
 756                                 usage_attribute.Inherited = (bool)field;
 757
 758                         return usage_attribute;
 759                 }
 760
 761                 /// <summary>
 762                 /// Returns custom name of indexer
 763                 /// </summary>
 764                 public string GetIndexerAttributeValue ()
 765                 {
 766                         if (pos_values == null)
 767                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 768                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 769                                 Resolve ();
 770
 771                         if (resolve_error)
 772                                 return null;
 773
 774                         return pos_values [0] as string;
 775                 }
 776
 777                 /// <summary>
 778                 /// Returns condition of ConditionalAttribute
 779                 /// </summary>
 780                 public string GetConditionalAttributeValue ()
 781                 {
 782                         if (pos_values == null)
 783                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 784                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 785                                 Resolve ();
 786
 787                         if (resolve_error)
 788                                 return null;
 789
 790                         return (string)pos_values [0];
 791                 }
 792
 793                 /// <summary>
 794                 /// Creates the instance of ObsoleteAttribute from this attribute instance
 795                 /// </summary>
 796                 public ObsoleteAttribute GetObsoleteAttribute ()
 797                 {
 798                         if (pos_values == null)
 799                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 800                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 801                                 Resolve ();
 802
 803                         if (resolve_error)
 804                                 return null;
 805
 806                         if (pos_values == null || pos_values.Length == 0)
 807                                 return new ObsoleteAttribute ();
 808
 809                         if (pos_values.Length == 1)
 810                                 return new ObsoleteAttribute ((string)pos_values [0]);
 811
 812                         return new ObsoleteAttribute ((string)pos_values [0], (bool)pos_values [1]);
 813                 }
 814
 815                 /// <summary>
 816                 /// Returns value of CLSCompliantAttribute contructor parameter but because the method can be called
 817                 /// before ApplyAttribute. We need to resolve the arguments.
 818                 /// This situation occurs when class deps is differs from Emit order.
 819                 /// </summary>
 820                 public bool GetClsCompliantAttributeValue ()
 821                 {
 822                         if (pos_values == null)
 823                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 824                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 825                                 Resolve ();
 826
 827                         if (resolve_error)
 828                                 return false;
 829
 830                         return (bool)pos_values [0];
 831                 }
 832
 833                 public Type GetCoClassAttributeValue ()
 834                 {
 835                         if (pos_values == null)
 836                                 Resolve ();
 837
 838                         if (resolve_error)
 839                                 return null;
 840
 841                         return (Type)pos_values [0];
 842                 }
 843
 844                 public bool CheckTarget ()
 845                 {
 846                         string[] valid_targets = Owner.ValidAttributeTargets;
 847                         if (ExplicitTarget == null || ExplicitTarget == valid_targets [0]) {
 848                                 Target = Owner.AttributeTargets;
 849                                 return true;
 850                         }
 851
 852                         // TODO: we can skip the first item
 853                         if (((IList) valid_targets).Contains (ExplicitTarget)) {
 854                                 switch (ExplicitTarget) {
 855                                 case "return": Target = AttributeTargets.ReturnValue; return true;
 856                                 case "param": Target = AttributeTargets.Parameter; return true;
 857                                 case "field": Target = AttributeTargets.Field; return true;
 858                                 case "method": Target = AttributeTargets.Method; return true;
 859                                 case "property": Target = AttributeTargets.Property; return true;
 860                                 }
 861                                 throw new InternalErrorException ("Unknown explicit target: " + ExplicitTarget);
 862                         }
 863
 864                         StringBuilder sb = new StringBuilder ();
 865                         foreach (string s in valid_targets) {
 866                                 sb.Append (s);
 867                                 sb.Append (", ");
 868                         }
 869                         sb.Remove (sb.Length - 2, 2);
 870                         Report.Error (657, Location, "`{0}' is not a valid attribute location for this declaration. " +
 871                                 "Valid attribute locations for this declaration are `{1}'", ExplicitTarget, sb.ToString ());
 872                         return false;
 873                 }
 874
 875                 /// <summary>
 876                 /// Tests permitted SecurityAction for assembly or other types
 877                 /// </summary>
 878                 protected virtual bool IsSecurityActionValid (bool for_assembly)
 879                 {
 880                         SecurityAction action = GetSecurityActionValue ();
 881
 882                         switch (action) {
 883                         case SecurityAction.Demand:
 884                         case SecurityAction.Assert:
 885                         case SecurityAction.Deny:
 886                         case SecurityAction.PermitOnly:
 887                         case SecurityAction.LinkDemand:
 888                         case SecurityAction.InheritanceDemand:
 889                                 if (!for_assembly)
 890                                         return true;
 891                                 break;
 892
 893                         case SecurityAction.RequestMinimum:
 894                         case SecurityAction.RequestOptional:
 895                         case SecurityAction.RequestRefuse:
 896                                 if (for_assembly)
 897                                         return true;
 898                                 break;
 899
 900                         default:
 901                                 Error_AttributeEmitError ("SecurityAction is out of range");
 902                                 return false;
 903                         }
 904
 905                         Error_AttributeEmitError (String.Concat ("SecurityAction `", action, "' is not valid for this declaration"));
 906                         return false;
 907                 }
 908
 909                 System.Security.Permissions.SecurityAction GetSecurityActionValue ()
 910                 {
 911                         return (SecurityAction)pos_values [0];
 912                 }
 913
 914                 /// <summary>
 915                 /// Creates instance of SecurityAttribute class and add result of CreatePermission method to permission table.
 916                 /// </summary>
 917                 /// <returns></returns>
 918                 public void ExtractSecurityPermissionSet (ListDictionary permissions)
 919                 {
 920                         Type orig_assembly_type = null;
 921
 922                         if (TypeManager.LookupDeclSpace (Type) != null) {
 923                                 if (!RootContext.StdLib) {
 924                                         orig_assembly_type = Type.GetType (Type.FullName);
 925                                 } else {
 926                                         string orig_version_path = Environment.GetEnvironmentVariable ("__SECURITY_BOOTSTRAP_DB");
 927                                         if (orig_version_path == null) {
 928                                                 Error_AttributeEmitError ("security custom attributes can not be referenced from defining assembly");
 929                                                 return;
 930                                         }
 931
 932                                         if (orig_sec_assembly == null) {
 933                                                 string file = Path.Combine (orig_version_path, Driver.OutputFile);
 934                                                 orig_sec_assembly = Assembly.LoadFile (file);
 935                                         }
 936
 937                                         orig_assembly_type = orig_sec_assembly.GetType (Type.FullName, true);
 938                                         if (orig_assembly_type == null) {
 939                                                 Report.Warning (-112, 1, Location, "Self-referenced security attribute `{0}' " +
 940                                                                 "was not found in previous version of assembly");
 941                                                 return;
 942                                         }
 943                                 }
 944                         }
 945
 946                         SecurityAttribute sa;
 947                         // For all non-selfreferencing security attributes we can avoid all hacks
 948                         if (orig_assembly_type == null) {
 949                                 sa = (SecurityAttribute) Activator.CreateInstance (Type, pos_values);
 950
 951                                 if (prop_info_arr != null) {
 952                                         for (int i = 0; i < prop_info_arr.Length; ++i) {
 953                                                 PropertyInfo pi = prop_info_arr [i];
 954                                                 pi.SetValue (sa, prop_values_arr [i], null);
 955                                         }
 956                                 }
 957                         } else {
 958                                 // HACK: All security attributes have same ctor syntax
 959                                 sa = (SecurityAttribute) Activator.CreateInstance (orig_assembly_type, new object[] { GetSecurityActionValue () } );
 960
 961                                 // All types are from newly created assembly but for invocation with old one we need to convert them
 962                                 if (prop_info_arr != null) {
 963                                         for (int i = 0; i < prop_info_arr.Length; ++i) {
 964                                                 PropertyInfo emited_pi = prop_info_arr [i];
 965                                                 // FIXME: We are missing return type filter
 966                                                 // TODO: pi can be null
 967                                                 PropertyInfo pi = orig_assembly_type.GetProperty (emited_pi.Name);
 968
 969                                                 object old_instance = pi.PropertyType.IsEnum ?
 970                                                         System.Enum.ToObject (pi.PropertyType, prop_values_arr [i]) :
 971                                                         prop_values_arr [i];
 972
 973                                                 pi.SetValue (sa, old_instance, null);
 974                                         }
 975                                 }
 976                         }
 977
 978                         IPermission perm;
 979                         perm = sa.CreatePermission ();
 980                         SecurityAction action = GetSecurityActionValue ();
 981
 982                         // IS is correct because for corlib we are using an instance from old corlib
 983                         if (!(perm is System.Security.CodeAccessPermission)) {
 984                                 switch (action) {
 985                                 case SecurityAction.Demand:
 986                                         action = (SecurityAction)13;
 987                                         break;
 988                                 case SecurityAction.LinkDemand:
 989                                         action = (SecurityAction)14;
 990                                         break;
 991                                 case SecurityAction.InheritanceDemand:
 992                                         action = (SecurityAction)15;
 993                                         break;
 994                                 }
 995                         }
 996
 997                         PermissionSet ps = (PermissionSet)permissions [action];
 998                         if (ps == null) {
 999                                 if (sa is PermissionSetAttribute)
1000                                         ps = new PermissionSet (sa.Unrestricted ? PermissionState.Unrestricted : PermissionState.None);
1001                                 else
1002                                         ps = new PermissionSet (PermissionState.None);
1003
1004                                 permissions.Add (action, ps);
1005                         } else if (!ps.IsUnrestricted () && (sa is PermissionSetAttribute) && sa.Unrestricted) {
1006                                 ps = ps.Union (new PermissionSet (PermissionState.Unrestricted));
1007                                 permissions [action] = ps;
1008                         }
1009                         ps.AddPermission (perm);
1010                 }
1011
1012                 public object GetPropertyValue (string name)
1013                 {
1014                         if (prop_info_arr == null)
1015                                 return null;
1016
1017                         for (int i = 0; i < prop_info_arr.Length; ++i) {
1018                                 if (prop_info_arr [i].Name == name)
1019                                         return prop_values_arr [i];
1020                         }
1021
1022                         return null;
1023                 }
1024
1025                 //
1026                 // Theoretically, we can get rid of this, since FieldBuilder.SetCustomAttribute()
1027                 // and ParameterBuilder.SetCustomAttribute() are supposed to handle this attribute.
1028                 // However, we can't, since it appears that the .NET 1.1 SRE hangs when given a MarshalAsAttribute.
1029                 //
1030 #if !NET_2_0
1031                 public UnmanagedMarshal GetMarshal (Attributable attr)
1032                 {
1033                         UnmanagedType UnmanagedType;
1034                         if (!RootContext.StdLib || pos_values [0].GetType () != typeof (UnmanagedType))
1035                                 UnmanagedType = (UnmanagedType) System.Enum.ToObject (typeof (UnmanagedType), pos_values [0]);
1036                         else
1037                                 UnmanagedType = (UnmanagedType) pos_values [0];
1038
1039                         object value = GetFieldValue ("SizeParamIndex");
1040                         if (value != null && UnmanagedType != UnmanagedType.LPArray) {
1041                                 Error_AttributeEmitError ("SizeParamIndex field is not valid for the specified unmanaged type");
1042                                 return null;
1043                         }
1044
1045                         object o = GetFieldValue ("ArraySubType");
1046                         UnmanagedType array_sub_type = o == null ? (UnmanagedType) 0x50 /* NATIVE_MAX */ : (UnmanagedType) o;
1047
1048                         switch (UnmanagedType) {
1049                         case UnmanagedType.CustomMarshaler: {
1050                                 MethodInfo define_custom = typeof (UnmanagedMarshal).GetMethod ("DefineCustom",
1051                                         BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
1052                                 if (define_custom == null) {
1053                                         Report.RuntimeMissingSupport (Location, "set marshal info");
1054                                         return null;
1055                                 }
1056
1057                                 object [] args = new object [4];
1058                                 args [0] = GetFieldValue ("MarshalTypeRef");
1059                                 args [1] = GetFieldValue ("MarshalCookie");
1060                                 args [2] = GetFieldValue ("MarshalType");
1061                                 args [3] = Guid.Empty;
1062                                 return (UnmanagedMarshal) define_custom.Invoke (null, args);
1063                         }
1064                         case UnmanagedType.LPArray: {
1065                                 object size_const = GetFieldValue ("SizeConst");
1066                                 object size_param_index = GetFieldValue ("SizeParamIndex");
1067
1068                                 if ((size_const != null) || (size_param_index != null)) {
1069                                         MethodInfo define_array = typeof (UnmanagedMarshal).GetMethod ("DefineLPArrayInternal",
1070                                                 BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
1071                                         if (define_array == null) {
1072                                                 Report.RuntimeMissingSupport (Location, "set marshal info");
1073                                                 return null;
1074                                         }
1075
1076                                         object [] args = new object [3];
1077                                         args [0] = array_sub_type;
1078                                         args [1] = size_const == null ? -1 : size_const;
1079                                         args [2] = size_param_index == null ? -1 : size_param_index;
1080                                         return (UnmanagedMarshal) define_array.Invoke (null, args);
1081                                 }
1082                                 else
1083                                         return UnmanagedMarshal.DefineLPArray (array_sub_type);
1084                         }
1085                         case UnmanagedType.SafeArray:
1086                                 return UnmanagedMarshal.DefineSafeArray (array_sub_type);
1087
1088                         case UnmanagedType.ByValArray:
1089                                 FieldBase fm = attr as FieldBase;
1090                                 if (fm == null) {
1091                                         Error_AttributeEmitError ("Specified unmanaged type is only valid on fields");
1092                                         return null;
1093                                 }
1094                                 return UnmanagedMarshal.DefineByValArray ((int) GetFieldValue ("SizeConst"));
1095
1096                         case UnmanagedType.ByValTStr:
1097                                 return UnmanagedMarshal.DefineByValTStr ((int) GetFieldValue ("SizeConst"));
1098
1099                         default:
1100                                 return UnmanagedMarshal.DefineUnmanagedMarshal (UnmanagedType);
1101                         }
1102                 }
1103
1104                 object GetFieldValue (string name)
1105                 {
1106                         int i;
1107                         if (field_info_arr == null)
1108                                 return null;
1109                         i = 0;
1110                         foreach (FieldInfo fi in field_info_arr) {
1111                                 if (fi.Name == name)
1112                                         return GetValue (field_values_arr [i]);
1113                                 i++;
1114                         }
1115                         return null;
1116                 }
1117
1118                 static object GetValue (object value)
1119                 {
1120                         if (value is EnumConstant)
1121                                 return ((EnumConstant) value).GetValue ();
1122                         else
1123                                 return value;
1124                 }
1125
1126 #endif
1127
1128                 public CharSet GetCharSetValue ()
1129                 {
1130                         return (CharSet)System.Enum.Parse (typeof (CharSet), pos_values [0].ToString ());
1131                 }
1132
1133                 public bool HasField (string fieldName)
1134                 {
1135                         if (field_info_arr == null)
1136                                 return false;
1137
1138                         foreach (FieldInfo fi in field_info_arr) {
1139                                 if (fi.Name == fieldName)
1140                                         return true;
1141                         }
1142
1143                         return false;
1144                 }
1145
1146                 public bool IsInternalMethodImplAttribute {
1147                         get {
1148                                 if (Type != TypeManager.methodimpl_attr_type)
1149                                         return false;
1150
1151                                 MethodImplOptions options;
1152                                 if (pos_values[0].GetType () != typeof (MethodImplOptions))
1153                                         options = (MethodImplOptions)System.Enum.ToObject (typeof (MethodImplOptions), pos_values[0]);
1154                                 else
1155                                         options = (MethodImplOptions)pos_values[0];
1156
1157                                 return (options & MethodImplOptions.InternalCall) != 0;
1158                         }
1159                 }
1160
1161                 public LayoutKind GetLayoutKindValue ()
1162                 {
1163                         if (!RootContext.StdLib || pos_values [0].GetType () != typeof (LayoutKind))
1164                                 return (LayoutKind)System.Enum.ToObject (typeof (LayoutKind), pos_values [0]);
1165
1166                         return (LayoutKind)pos_values [0];
1167                 }
1168
1169                 public object GetParameterDefaultValue ()
1170                 {
1171                         return pos_values [0];
1172                 }
1173
1174                 public override bool Equals (object obj)
1175                 {
1176                         Attribute a = obj as Attribute;
1177                         if (a == null)
1178                                 return false;
1179
1180                         return Type == a.Type && Target == a.Target;
1181                 }
1182
1183                 public override int GetHashCode ()
1184                 {
1185                         return base.GetHashCode ();
1186                 }
1187
1188                 /// <summary>
1189                 /// Emit attribute for Attributable symbol
1190                 /// </summary>
1191                 public void Emit (ListDictionary allEmitted)
1192                 {
1193                         CustomAttributeBuilder cb = Resolve ();
1194                         if (cb == null)
1195                                 return;
1196
1197                         AttributeUsageAttribute usage_attr = GetAttributeUsage (Type);
1198                         if ((usage_attr.ValidOn & Target) == 0) {
1199                                 Report.Error (592, Location, "The attribute `{0}' is not valid on this declaration type. " +
1200                                               "It is valid on `{1}' declarations only",
1201                                         GetSignatureForError (), GetValidTargets ());
1202                                 return;
1203                         }
1204
1205                         try {
1206                                 foreach (Attributable owner in owners)
1207                                         owner.ApplyAttributeBuilder (this, cb);
1208                         }
1209                         catch (Exception e) {
1210                                 Error_AttributeEmitError (e.Message);
1211                                 return;
1212                         }
1213
1214                         if (!usage_attr.AllowMultiple && allEmitted != null) {
1215                                 if (allEmitted.Contains (this)) {
1216                                         ArrayList a = allEmitted [this] as ArrayList;
1217                                         if (a == null) {
1218                                                 a = new ArrayList (2);
1219                                                 allEmitted [this] = a;
1220                                         }
1221                                         a.Add (this);
1222                                 } else {
1223                                         allEmitted.Add (this, null);
1224                                 }
1225                         }
1226
1227                         if (!RootContext.VerifyClsCompliance)
1228                                 return;
1229
1230                         // Here we are testing attribute arguments for array usage (error 3016)
1231                         if (Owner.IsClsComplianceRequired ()) {
1232                                 if (PosArguments != null) {
1233                                         foreach (Argument arg in PosArguments) {
1234                                                 // Type is undefined (was error 246)
1235                                                 if (arg.Type == null)
1236                                                         return;
1237
1238                                                 if (arg.Type.IsArray) {
1239                                                         Report.Warning (3016, 1, Location, "Arrays as attribute arguments are not CLS-compliant");
1240                                                         return;
1241                                                 }
1242                                         }
1243                                 }
1244
1245                                 if (NamedArguments == null)
1246                                         return;
1247
1248                                 foreach (DictionaryEntry de in NamedArguments) {
1249                                         Argument arg  = (Argument) de.Value;
1250
1251                                         // Type is undefined (was error 246)
1252                                         if (arg.Type == null)
1253                                                 return;
1254
1255                                         if (arg.Type.IsArray) {
1256                                                 Report.Warning (3016, 1, Location, "Arrays as attribute arguments are not CLS-compliant");
1257                                                 return;
1258                                         }
1259                                 }
1260                         }
1261                 }
1262
1263                 private Expression GetValue ()
1264                 {
1265                         if (PosArguments == null || PosArguments.Count < 1)
1266                                 return null;
1267
1268                         return ((Argument) PosArguments [0]).Expr;
1269                 }
1270
1271                 public string GetString ()
1272                 {
1273                         Expression e = GetValue ();
1274                         if (e is StringConstant)
1275                                 return ((StringConstant)e).Value;
1276                         return null;
1277                 }
1278
1279                 public bool GetBoolean ()
1280                 {
1281                         Expression e = GetValue ();
1282                         if (e is BoolConstant)
1283                                 return ((BoolConstant)e).Value;
1284                         return false;
1285                 }
1286
1287                 public Type GetArgumentType ()
1288                 {
1289                         TypeOf e = GetValue () as TypeOf;
1290                         if (e == null)
1291                                 return null;
1292                         return e.TypeArgument;
1293                 }
1294
1295                 public override Expression CreateExpressionTree (EmitContext ec)
1296                 {
1297                         throw new NotSupportedException ("ET");
1298                 }
1299
1300                 public override Expression DoResolve (EmitContext ec)
1301                 {
1302                         throw new NotImplementedException ();
1303                 }
1304
1305                 public override void Emit (EmitContext ec)
1306                 {
1307                         throw new NotImplementedException ();
1308                 }
1309         }
1310
1311
1312         /// <summary>
1313         /// For global attributes (assembly, module) we need special handling.
1314         /// Attributes can be located in the several files
1315         /// </summary>
1316         public class GlobalAttribute : Attribute
1317         {
1318                 public readonly NamespaceEntry ns;
1319
1320                 public GlobalAttribute (NamespaceEntry ns, string target,
1321                                         Expression left_expr, string identifier, object[] args, Location loc, bool nameEscaped):
1322                         base (target, left_expr, identifier, args, loc, nameEscaped)
1323                 {
1324                         this.ns = ns;
1325                         this.owners = new Attributable[1];
1326                 }
1327
1328                 public override void AttachTo (Attributable owner)
1329                 {
1330                         if (ExplicitTarget == "assembly") {
1331                                 owners [0] = CodeGen.Assembly;
1332                                 return;
1333                         }
1334                         if (ExplicitTarget == "module") {
1335                                 owners [0] = CodeGen.Module;
1336                                 return;
1337                         }
1338                         throw new NotImplementedException ("Unknown global explicit target " + ExplicitTarget);
1339                 }
1340
1341                 void Enter ()
1342                 {
1343                         // RootContext.ToplevelTypes has a single NamespaceEntry which gets overwritten
1344                         // each time a new file is parsed.  However, we need to use the NamespaceEntry
1345                         // in effect where the attribute was used.  Since code elsewhere cannot assume
1346                         // that the NamespaceEntry is right, just overwrite it.
1347                         //
1348                         // Precondition: RootContext.ToplevelTypes == null
1349
1350                         if (RootContext.ToplevelTypes.NamespaceEntry != null)
1351                                 throw new InternalErrorException (Location + " non-null NamespaceEntry");
1352
1353                         RootContext.ToplevelTypes.NamespaceEntry = ns;
1354                 }
1355
1356                 protected override bool IsSecurityActionValid (bool for_assembly)
1357                 {
1358                         return base.IsSecurityActionValid (true);
1359                 }
1360
1361                 void Leave ()
1362                 {
1363                         RootContext.ToplevelTypes.NamespaceEntry = null;
1364                 }
1365
1366                 protected override TypeExpr ResolveAsTypeTerminal (Expression expr, IResolveContext ec, bool silent)
1367                 {
1368                         try {
1369                                 Enter ();
1370                                 return base.ResolveAsTypeTerminal (expr, ec, silent);
1371                         }
1372                         finally {
1373                                 Leave ();
1374                         }
1375                 }
1376
1377                 protected override ConstructorInfo ResolveConstructor (EmitContext ec)
1378                 {
1379                         try {
1380                                 Enter ();
1381                                 return base.ResolveConstructor (ec);
1382                         }
1383                         finally {
1384                                 Leave ();
1385                         }
1386                 }
1387
1388                 protected override bool ResolveNamedArguments (EmitContext ec)
1389                 {
1390                         try {
1391                                 Enter ();
1392                                 return base.ResolveNamedArguments (ec);
1393                         }
1394                         finally {
1395                                 Leave ();
1396                         }
1397                 }
1398         }
1399
1400         public class Attributes {
1401                 public readonly ArrayList Attrs;
1402
1403                 public Attributes (Attribute a)
1404                 {
1405                         Attrs = new ArrayList ();
1406                         Attrs.Add (a);
1407                 }
1408
1409                 public Attributes (ArrayList attrs)
1410                 {
1411                         Attrs = attrs;
1412                 }
1413
1414                 public void AddAttributes (ArrayList attrs)
1415                 {
1416                         Attrs.AddRange (attrs);
1417                 }
1418
1419                 public void AttachTo (Attributable attributable)
1420                 {
1421                         foreach (Attribute a in Attrs)
1422                                 a.AttachTo (attributable);
1423                 }
1424
1425                 public Attributes Clone ()
1426                 {
1427                         ArrayList al = new ArrayList (Attrs.Count);
1428                         foreach (Attribute a in Attrs)
1429                                 al.Add (a.Clone ());
1430
1431                         return new Attributes (al);
1432                 }
1433
1434                 /// <summary>
1435                 /// Checks whether attribute target is valid for the current element
1436                 /// </summary>
1437                 public bool CheckTargets ()
1438                 {
1439                         foreach (Attribute a in Attrs) {
1440                                 if (!a.CheckTarget ())
1441                                         return false;
1442                         }
1443                         return true;
1444                 }
1445
1446                 public Attribute Search (Type t)
1447                 {
1448                         foreach (Attribute a in Attrs) {
1449                                 if (a.ResolveType () == t)
1450                                         return a;
1451                         }
1452                         return null;
1453                 }
1454
1455                 /// <summary>
1456                 /// Returns all attributes of type 't'. Use it when attribute is AllowMultiple = true
1457                 /// </summary>
1458                 public Attribute[] SearchMulti (Type t)
1459                 {
1460                         ArrayList ar = null;
1461
1462                         foreach (Attribute a in Attrs) {
1463                                 if (a.ResolveType () == t) {
1464                                         if (ar == null)
1465                                                 ar = new ArrayList ();
1466                                         ar.Add (a);
1467                                 }
1468                         }
1469
1470                         return ar == null ? null : ar.ToArray (typeof (Attribute)) as Attribute[];
1471                 }
1472
1473                 public void Emit ()
1474                 {
1475                         CheckTargets ();
1476
1477                         ListDictionary ld = Attrs.Count > 1 ? new ListDictionary () : null;
1478
1479                         foreach (Attribute a in Attrs)
1480                                 a.Emit (ld);
1481
1482                         if (ld == null || ld.Count == 0)
1483                                 return;
1484
1485                         foreach (DictionaryEntry d in ld) {
1486                                 if (d.Value == null)
1487                                         continue;
1488
1489                                 foreach (Attribute collision in (ArrayList)d.Value)
1490                                         Report.SymbolRelatedToPreviousError (collision.Location, "");
1491
1492                                 Attribute a = (Attribute)d.Key;
1493                                 Report.Error (579, a.Location, "The attribute `{0}' cannot be applied multiple times",
1494                                         a.GetSignatureForError ());
1495                         }
1496                 }
1497
1498                 public bool Contains (Type t)
1499                 {
1500                         return Search (t) != null;
1501                 }
1502         }
1503
1504         /// <summary>
1505         /// Helper class for attribute verification routine.
1506         /// </summary>
1507         sealed class AttributeTester
1508         {
1509                 static PtrHashtable analyzed_types;
1510                 static PtrHashtable analyzed_types_obsolete;
1511                 static PtrHashtable analyzed_member_obsolete;
1512                 static PtrHashtable analyzed_method_excluded;
1513                 static PtrHashtable fixed_buffer_cache;
1514
1515                 static object TRUE = new object ();
1516                 static object FALSE = new object ();
1517
1518                 static AttributeTester ()
1519                 {
1520                         Reset ();
1521                 }
1522
1523                 private AttributeTester ()
1524                 {
1525                 }
1526
1527                 public static void Reset ()
1528                 {
1529                         analyzed_types = new PtrHashtable ();
1530                         analyzed_types_obsolete = new PtrHashtable ();
1531                         analyzed_member_obsolete = new PtrHashtable ();
1532                         analyzed_method_excluded = new PtrHashtable ();
1533                         fixed_buffer_cache = new PtrHashtable ();
1534                 }
1535
1536                 public enum Result {
1537                         Ok,
1538                         RefOutArrayError,
1539                         ArrayArrayError
1540                 }
1541
1542                 /// <summary>
1543                 /// Returns true if parameters of two compared methods are CLS-Compliant.
1544                 /// It tests differing only in ref or out, or in array rank.
1545                 /// </summary>
1546                 public static Result AreOverloadedMethodParamsClsCompliant (AParametersCollection pa, AParametersCollection pb)
1547                 {
1548                         Type [] types_a = pa.Types;
1549                         Type [] types_b = pb.Types;
1550                         if (types_a == null || types_b == null)
1551                                 return Result.Ok;
1552
1553                         if (types_a.Length != types_b.Length)
1554                                 return Result.Ok;
1555
1556                         Result result = Result.Ok;
1557                         for (int i = 0; i < types_b.Length; ++i) {
1558                                 Type aType = types_a [i];
1559                                 Type bType = types_b [i];
1560
1561                                 if (aType.IsArray && bType.IsArray) {
1562                                         Type a_el_type = aType.GetElementType ();
1563                                         Type b_el_type = bType.GetElementType ();
1564                                         if (aType.GetArrayRank () != bType.GetArrayRank () && a_el_type == b_el_type) {
1565                                                 result = Result.RefOutArrayError;
1566                                                 continue;
1567                                         }
1568
1569                                         if (a_el_type.IsArray || b_el_type.IsArray) {
1570                                                 result = Result.ArrayArrayError;
1571                                                 continue;
1572                                         }
1573                                 }
1574
1575                                 if (aType != bType)
1576                                         return Result.Ok;
1577
1578                                 if (pa.FixedParameters [i].ModFlags != pb.FixedParameters [i].ModFlags)
1579                                         result = Result.RefOutArrayError;
1580                         }
1581                         return result;
1582                 }
1583
1584                 /// <summary>
1585                 /// This method tests the CLS compliance of external types. It doesn't test type visibility.
1586                 /// </summary>
1587                 public static bool IsClsCompliant (Type type)
1588                 {
1589                         if (type == null)
1590                                 return true;
1591
1592                         object type_compliance = analyzed_types[type];
1593                         if (type_compliance != null)
1594                                 return type_compliance == TRUE;
1595
1596                         if (type.IsPointer) {
1597                                 analyzed_types.Add (type, FALSE);
1598                                 return false;
1599                         }
1600
1601                         bool result;
1602                         if (type.IsArray) {
1603                                 result = IsClsCompliant (TypeManager.GetElementType (type));
1604                         } else if (TypeManager.IsNullableType (type)) {
1605                                 result = IsClsCompliant (TypeManager.GetTypeArguments (type) [0]);
1606                         } else {
1607                                 result = AnalyzeTypeCompliance (type);
1608                         }
1609                         analyzed_types.Add (type, result ? TRUE : FALSE);
1610                         return result;
1611                 }
1612
1613                 /// <summary>
1614                 /// Returns IFixedBuffer implementation if field is fixed buffer else null.
1615                 /// </summary>
1616                 public static IFixedBuffer GetFixedBuffer (FieldInfo fi)
1617                 {
1618                         // Fixed buffer helper type is generated as value type
1619                         if (!fi.FieldType.IsValueType)
1620                                 return null;
1621
1622                         FieldBase fb = TypeManager.GetField (fi);
1623                         if (fb != null) {
1624                                 return fb as IFixedBuffer;
1625                         }
1626
1627                         if (TypeManager.GetConstant (fi) != null)
1628                                 return null;
1629
1630                         object o = fixed_buffer_cache [fi];
1631                         if (o == null) {
1632                                 if (TypeManager.fixed_buffer_attr_type == null)
1633                                         return null;
1634
1635                                 if (!fi.IsDefined (TypeManager.fixed_buffer_attr_type, false)) {
1636                                         fixed_buffer_cache.Add (fi, FALSE);
1637                                         return null;
1638                                 }
1639
1640                                 IFixedBuffer iff = new FixedFieldExternal (fi);
1641                                 fixed_buffer_cache.Add (fi, iff);
1642                                 return iff;
1643                         }
1644
1645                         if (o == FALSE)
1646                                 return null;
1647
1648                         return (IFixedBuffer)o;
1649                 }
1650
1651                 public static void VerifyModulesClsCompliance ()
1652                 {
1653                         Module[] modules = RootNamespace.Global.Modules;
1654                         if (modules == null)
1655                                 return;
1656
1657                         // The first module is generated assembly
1658                         for (int i = 1; i < modules.Length; ++i) {
1659                                 Module module = modules [i];
1660                                 if (!GetClsCompliantAttributeValue (module, null)) {
1661                                         Report.Error (3013, "Added modules must be marked with the CLSCompliant attribute " +
1662                                                       "to match the assembly", module.Name);
1663                                         return;
1664                                 }
1665                         }
1666                 }
1667
1668                 public static Type GetImportedIgnoreCaseClsType (string name)
1669                 {
1670                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
1671                                 Type t = a.GetType (name, false, true);
1672                                 if (t == null)
1673                                         continue;
1674
1675                                 if (IsClsCompliant (t))
1676                                         return t;
1677                         }
1678                         return null;
1679                 }
1680
1681                 static bool GetClsCompliantAttributeValue (ICustomAttributeProvider attribute_provider, Assembly a)
1682                 {
1683                         if (TypeManager.cls_compliant_attribute_type == null)
1684                                 return false;
1685
1686                         object[] cls_attr = attribute_provider.GetCustomAttributes (TypeManager.cls_compliant_attribute_type, false);
1687                         if (cls_attr.Length == 0) {
1688                                 if (a == null)
1689                                         return false;
1690
1691                                 return GetClsCompliantAttributeValue (a, null);
1692                         }
1693
1694                         return ((CLSCompliantAttribute)cls_attr [0]).IsCompliant;
1695                 }
1696
1697                 static bool AnalyzeTypeCompliance (Type type)
1698                 {
1699                         type = TypeManager.DropGenericTypeArguments (type);
1700                         DeclSpace ds = TypeManager.LookupDeclSpace (type);
1701                         if (ds != null) {
1702                                 return ds.IsClsComplianceRequired ();
1703                         }
1704
1705                         if (TypeManager.IsGenericParameter (type))
1706                                 return true;
1707
1708                         return GetClsCompliantAttributeValue (type, type.Assembly);
1709                 }
1710
1711                 /// <summary>
1712                 /// Returns instance of ObsoleteAttribute when type is obsolete
1713                 /// </summary>
1714                 public static ObsoleteAttribute GetObsoleteAttribute (Type type)
1715                 {
1716                         object type_obsolete = analyzed_types_obsolete [type];
1717                         if (type_obsolete == FALSE)
1718                                 return null;
1719
1720                         if (type_obsolete != null)
1721                                 return (ObsoleteAttribute)type_obsolete;
1722
1723                         ObsoleteAttribute result = null;
1724                         if (TypeManager.HasElementType (type)) {
1725                                 result = GetObsoleteAttribute (TypeManager.GetElementType (type));
1726                         } else if (TypeManager.IsGenericParameter (type) || TypeManager.IsGenericType (type))
1727                                 return null;
1728                         else {
1729                                 DeclSpace type_ds = TypeManager.LookupDeclSpace (type);
1730
1731                                 // Type is external, we can get attribute directly
1732                                 if (type_ds == null) {
1733                                         if (TypeManager.obsolete_attribute_type != null) {
1734                                                 object [] attribute = type.GetCustomAttributes (TypeManager.obsolete_attribute_type, false);
1735                                                 if (attribute.Length == 1)
1736                                                         result = (ObsoleteAttribute) attribute [0];
1737                                         }
1738                                 } else {
1739                                         result = type_ds.GetObsoleteAttribute ();
1740                                 }
1741                         }
1742
1743                         // Cannot use .Add because of corlib bootstrap
1744                         analyzed_types_obsolete [type] = result == null ? FALSE : result;
1745                         return result;
1746                 }
1747
1748                 /// <summary>
1749                 /// Returns instance of ObsoleteAttribute when method is obsolete
1750                 /// </summary>
1751                 public static ObsoleteAttribute GetMethodObsoleteAttribute (MethodBase mb)
1752                 {
1753                         IMethodData mc = TypeManager.GetMethod (mb);
1754                         if (mc != null)
1755                                 return mc.GetObsoleteAttribute ();
1756
1757                         // compiler generated methods are not registered by AddMethod
1758                         if (mb.DeclaringType is TypeBuilder)
1759                                 return null;
1760
1761                         MemberInfo mi = TypeManager.GetPropertyFromAccessor (mb);
1762                         if (mi != null)
1763                                 return GetMemberObsoleteAttribute (mi);
1764
1765                         mi = TypeManager.GetEventFromAccessor (mb);
1766                         if (mi != null)
1767                                 return GetMemberObsoleteAttribute (mi);
1768
1769                         return GetMemberObsoleteAttribute (mb);
1770                 }
1771
1772                 /// <summary>
1773                 /// Returns instance of ObsoleteAttribute when member is obsolete
1774                 /// </summary>
1775                 public static ObsoleteAttribute GetMemberObsoleteAttribute (MemberInfo mi)
1776                 {
1777                         object type_obsolete = analyzed_member_obsolete [mi];
1778                         if (type_obsolete == FALSE)
1779                                 return null;
1780
1781                         if (type_obsolete != null)
1782                                 return (ObsoleteAttribute)type_obsolete;
1783
1784                         if ((mi.DeclaringType is TypeBuilder) || TypeManager.IsGenericType (mi.DeclaringType))
1785                                 return null;
1786
1787                         if (TypeManager.obsolete_attribute_type == null)
1788                                 return null;
1789
1790                         ObsoleteAttribute oa = System.Attribute.GetCustomAttribute (mi, TypeManager.obsolete_attribute_type, false)
1791                                 as ObsoleteAttribute;
1792                         analyzed_member_obsolete.Add (mi, oa == null ? FALSE : oa);
1793                         return oa;
1794                 }
1795
1796                 /// <summary>
1797                 /// Common method for Obsolete error/warning reporting.
1798                 /// </summary>
1799                 public static void Report_ObsoleteMessage (ObsoleteAttribute oa, string member, Location loc)
1800                 {
1801                         if (oa.IsError) {
1802                                 Report.Error (619, loc, "`{0}' is obsolete: `{1}'", member, oa.Message);
1803                                 return;
1804                         }
1805
1806                         if (oa.Message == null || oa.Message.Length == 0) {
1807                                 Report.Warning (612, 1, loc, "`{0}' is obsolete", member);
1808                                 return;
1809                         }
1810                         Report.Warning (618, 2, loc, "`{0}' is obsolete: `{1}'", member, oa.Message);
1811                 }
1812
1813                 public static bool IsConditionalMethodExcluded (MethodBase mb, Location loc)
1814                 {
1815                         object excluded = analyzed_method_excluded [mb];
1816                         if (excluded != null)
1817                                 return excluded == TRUE ? true : false;
1818
1819                         if (TypeManager.conditional_attribute_type == null)
1820                                 return false;
1821
1822                         ConditionalAttribute[] attrs = mb.GetCustomAttributes (TypeManager.conditional_attribute_type, true)
1823                                 as ConditionalAttribute[];
1824                         if (attrs.Length == 0) {
1825                                 analyzed_method_excluded.Add (mb, FALSE);
1826                                 return false;
1827                         }
1828
1829                         foreach (ConditionalAttribute a in attrs) {
1830                                 if (loc.CompilationUnit.IsConditionalDefined (a.ConditionString)) {
1831                                         analyzed_method_excluded.Add (mb, FALSE);
1832                                         return false;
1833                                 }
1834                         }
1835
1836                         analyzed_method_excluded.Add (mb, TRUE);
1837                         return true;
1838                 }
1839
1840                 /// <summary>
1841                 /// Analyzes class whether it has attribute which has ConditionalAttribute
1842                 /// and its condition is not defined.
1843                 /// </summary>
1844                 public static bool IsAttributeExcluded (Type type, Location loc)
1845                 {
1846                         if (!type.IsClass)
1847                                 return false;
1848
1849                         Class class_decl = TypeManager.LookupDeclSpace (type) as Class;
1850
1851                         // TODO: add caching
1852                         // TODO: merge all Type bases attribute caching to one cache to save memory
1853                         if (class_decl == null && TypeManager.conditional_attribute_type != null) {
1854                                 object[] attributes = type.GetCustomAttributes (TypeManager.conditional_attribute_type, false);
1855                                 foreach (ConditionalAttribute ca in attributes) {
1856                                         if (loc.CompilationUnit.IsConditionalDefined (ca.ConditionString))
1857                                                 return false;
1858                                 }
1859                                 return attributes.Length > 0;
1860                         }
1861
1862                         return class_decl.IsExcluded ();
1863                 }
1864
1865                 public static Type GetCoClassAttribute (Type type)
1866                 {
1867                         TypeContainer tc = TypeManager.LookupInterface (type);
1868                         if (tc == null) {
1869                                 if (TypeManager.coclass_attr_type == null)
1870                                         return null;
1871
1872                                 object[] o = type.GetCustomAttributes (TypeManager.coclass_attr_type, false);
1873                                 if (o.Length < 1)
1874                                         return null;
1875                                 return ((System.Runtime.InteropServices.CoClassAttribute)o[0]).CoClass;
1876                         }
1877
1878                         if (tc.OptAttributes == null || TypeManager.coclass_attr_type == null)
1879                                 return null;
1880
1881                         Attribute a = tc.OptAttributes.Search (TypeManager.coclass_attr_type);
1882                         if (a == null)
1883                                 return null;
1884
1885                         return a.GetCoClassAttributeValue ();
1886                 }
1887         }
1888 }