mcs/gmcs/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 // Licensed under the terms of the GNU GPL
   8 //
   9 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  10 //
  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                 Attributes attributes;
  36
  37                 public Attributable (Attributes attrs)
  38                 {
  39                         attributes = attrs;
  40                 }
  41
  42                 public Attributes OptAttributes
  43                 {
  44                         get {
  45                                 return attributes;
  46                         }
  47                         set {
  48                                 attributes = value;
  49                         }
  50                 }
  51
  52                 /// <summary>
  53                 /// Use member-specific procedure to apply attribute @a in @cb to the entity being built in @builder
  54                 /// </summary>
  55                 public abstract void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb);
  56
  57                 /// <summary>
  58                 /// Returns one AttributeTarget for this element.
  59                 /// </summary>
  60                 public abstract AttributeTargets AttributeTargets { get; }
  61
  62                 public abstract bool IsClsComplianceRequired (DeclSpace ds);
  63
  64                 /// <summary>
  65                 /// Gets list of valid attribute targets for explicit target declaration.
  66                 /// The first array item is default target. Don't break this rule.
  67                 /// </summary>
  68                 public abstract string[] ValidAttributeTargets { get; }
  69         };
  70
  71         public class Attribute {
  72                 public readonly string ExplicitTarget;
  73                 public AttributeTargets Target;
  74
  75                 // TODO: remove this member
  76                 public readonly string    Name;
  77                 public readonly Expression LeftExpr;
  78                 public readonly string Identifier;
  79
  80                 public readonly ArrayList Arguments;
  81
  82                 public readonly Location Location;
  83
  84                 public Type Type;
  85
  86                 bool resolve_error;
  87
  88                 static AttributeUsageAttribute DefaultUsageAttribute = new AttributeUsageAttribute (AttributeTargets.All);
  89                 static Assembly orig_sec_assembly;
  90
  91                 // non-null if named args present after Resolve () is called
  92                 PropertyInfo [] prop_info_arr;
  93                 FieldInfo [] field_info_arr;
  94                 object [] field_values_arr;
  95                 object [] prop_values_arr;
  96                 object [] pos_values;
  97
  98                 static PtrHashtable usage_attr_cache = new PtrHashtable ();
  99
 100                 public Attribute (string target, Expression left_expr, string identifier, ArrayList args, Location loc)
 101                 {
 102                         LeftExpr = left_expr;
 103                         Identifier = identifier;
 104                         Name = LeftExpr == null ? identifier : LeftExpr + "." + identifier;
 105                         Arguments = args;
 106                         Location = loc;
 107                         ExplicitTarget = target;
 108                 }
 109
 110                 void Error_InvalidNamedArgument (string name)
 111                 {
 112                         Report.Error (617, Location, "`{0}' is not a valid named attribute argument. Named attribute arguments must be fields which are not readonly, static, const or read-write properties which are public and not static",
 113                               name);
 114                 }
 115
 116                 void Error_InvalidNamedAgrumentType (string name)
 117                 {
 118                         Report.Error (655, Location, "`{0}' is not a valid named attribute argument because it is not a valid attribute parameter type", name);
 119                 }
 120
 121                 static void Error_AttributeArgumentNotValid (string extra, Location loc)
 122                 {
 123                         Report.Error (182, loc,
 124                                       "An attribute argument must be a constant expression, typeof " +
 125                                       "expression or array creation expression" + extra);
 126                 }
 127
 128                 static void Error_AttributeArgumentNotValid (Location loc)
 129                 {
 130                         Error_AttributeArgumentNotValid ("", loc);
 131                 }
 132
 133                 static void Error_TypeParameterInAttribute (Location loc)
 134                 {
 135                         Report.Error (
 136                                 -202, loc, "Can not use a type parameter in an attribute");
 137                 }
 138
 139                 /// <summary>
 140                 /// This is rather hack. We report many emit attribute error with same error to be compatible with
 141                 /// csc. But because csc has to report them this way because error came from ilasm we needn't.
 142                 /// </summary>
 143                 public void Error_AttributeEmitError (string inner)
 144                 {
 145                         Report.Error (647, Location, "Error during emitting `{0}' attribute. The reason is `{1}'", TypeManager.CSharpName (Type), inner);
 146                 }
 147
 148                 public void Error_InvalidSecurityParent ()
 149                 {
 150                         Error_AttributeEmitError ("it is attached to invalid parent");
 151                 }
 152
 153                 protected virtual FullNamedExpression ResolveAsTypeTerminal (Expression expr, EmitContext ec, bool silent)
 154                 {
 155                         return expr.ResolveAsTypeTerminal (ec, silent);
 156                 }
 157
 158                 protected virtual FullNamedExpression ResolveAsTypeStep (Expression expr, EmitContext ec, bool silent)
 159                 {
 160                         return expr.ResolveAsTypeStep (ec, silent);
 161                 }
 162
 163                 Type ResolvePossibleAttributeType (EmitContext ec, string name, bool silent, ref bool is_attr)
 164                 {
 165                         FullNamedExpression fn;
 166                         if (LeftExpr == null) {
 167                                 fn = ResolveAsTypeTerminal (new SimpleName (name, Location), ec, silent);
 168                         } else {
 169                                 fn = ResolveAsTypeStep (LeftExpr, ec, silent);
 170                                 if (fn == null)
 171                                         return null;
 172                                 fn = new MemberAccess (fn, name, Location).ResolveAsTypeTerminal (ec, silent);
 173                         }
 174
 175                         TypeExpr te = fn as TypeExpr;
 176                         if (te == null)
 177                                 return null;
 178
 179                         Type t = te.Type;
 180                         if (t.IsSubclassOf (TypeManager.attribute_type)) {
 181                                 is_attr = true;
 182                         } else if (!silent) {
 183                                 Report.SymbolRelatedToPreviousError (t);
 184                                 Report.Error (616, Location, "`{0}': is not an attribute class", TypeManager.CSharpName (t));
 185                         }
 186                         return t;
 187                 }
 188
 189                 /// <summary>
 190                 ///   Tries to resolve the type of the attribute. Flags an error if it can't, and complain is true.
 191                 /// </summary>
 192                 void ResolveAttributeType (EmitContext ec)
 193                 {
 194                         bool t1_is_attr = false;
 195                         Type t1 = ResolvePossibleAttributeType (ec, Identifier, true, ref t1_is_attr);
 196                         // FIXME: Shouldn't do this for quoted attributes: [@A]
 197                         bool t2_is_attr = false;
 198                         Type t2 = ResolvePossibleAttributeType (ec, Identifier + "Attribute", true, ref t2_is_attr);
 199
 200                         if (t1_is_attr && t2_is_attr) {
 201                                 Report.Error (1614, Location, "`{0}' is ambiguous between `{0}' and `{0}Attribute'. Use either `@{0}' or `{0}Attribute'", GetSignatureForError ());
 202                                 resolve_error = true;
 203                                 return;
 204                         }
 205                         if (t1_is_attr) {
 206                                 Type = t1;
 207                                 return;
 208                         }
 209
 210                         if (t2_is_attr) {
 211                                 Type = t2;
 212                                 return;
 213                         }
 214
 215                         if (t1 == null && t2 == null)
 216                                 ResolvePossibleAttributeType (ec, Identifier, false, ref t1_is_attr);
 217                         if (t1 != null)
 218                                 ResolvePossibleAttributeType (ec, Identifier, false, ref t1_is_attr);
 219                         if (t2 != null)
 220                                 ResolvePossibleAttributeType (ec, Identifier + "Attribute", false, ref t2_is_attr);
 221                         resolve_error = true;
 222                 }
 223
 224                 public virtual Type ResolveType (EmitContext ec)
 225                 {
 226                         if (Type == null && !resolve_error)
 227                                 ResolveAttributeType (ec);
 228                         return Type;
 229                 }
 230
 231                 public string GetSignatureForError ()
 232                 {
 233                         return LeftExpr == null ? Identifier : LeftExpr.GetSignatureForError () + "." + Identifier;
 234                 }
 235
 236                 //
 237                 // Given an expression, if the expression is a valid attribute-argument-expression
 238                 // returns an object that can be used to encode it, or null on failure.
 239                 //
 240                 public static bool GetAttributeArgumentExpression (Expression e, Location loc, Type arg_type, out object result)
 241                 {
 242                         if (e is EnumConstant) {
 243                                 if (RootContext.StdLib)
 244                                         result = ((EnumConstant)e).GetValueAsEnumType ();
 245                                 else
 246                                         result = ((EnumConstant)e).GetValue ();
 247
 248                                 return true;
 249                         }
 250
 251                         Constant constant = e as Constant;
 252                         if (constant != null) {
 253                                 if (e.Type != arg_type) {
 254                                         constant = Const.ChangeType (loc, constant, arg_type);
 255                                         if (constant == null) {
 256                                                 result = null;
 257                                                 Error_AttributeArgumentNotValid (loc);
 258                                                 return false;
 259                                         }
 260                                 }
 261                                 result = constant.GetValue ();
 262                                 return true;
 263                         } else if (e is TypeOf) {
 264                                 result = ((TypeOf) e).TypeArg;
 265                                 return true;
 266                         } else if (e is ArrayCreation){
 267                                 result =  ((ArrayCreation) e).EncodeAsAttribute ();
 268                                 if (result != null)
 269                                         return true;
 270                         } else if (e is EmptyCast) {
 271                                 Expression child = ((EmptyCast)e).Child;
 272                                 return GetAttributeArgumentExpression (child, loc, child.Type, out result);
 273                         }
 274
 275                         result = null;
 276                         Error_AttributeArgumentNotValid (loc);
 277                         return false;
 278                 }
 279
 280                 bool IsValidArgumentType (Type t)
 281                 {
 282                         return TypeManager.IsPrimitiveType (t) ||
 283                                 (t.IsArray && TypeManager.IsPrimitiveType (t.GetElementType ())) ||
 284                                 TypeManager.IsEnumType (t) ||
 285                                 t == TypeManager.string_type ||
 286                                 t == TypeManager.object_type ||
 287                                 t == TypeManager.type_type;
 288                 }
 289
 290                 // Cache for parameter-less attributes
 291                 static PtrHashtable att_cache = new PtrHashtable ();
 292
 293                 public CustomAttributeBuilder Resolve (EmitContext ec)
 294                 {
 295                         if (resolve_error)
 296                                 return null;
 297
 298                         resolve_error = true;
 299
 300                         if (Type == null) {
 301                                 ResolveAttributeType (ec);
 302                                 if (Type == null)
 303                                         return null;
 304                         }
 305
 306                         if (Type.IsAbstract) {
 307                                 Report.Error (653, Location, "Cannot apply attribute class `{0}' because it is abstract", GetSignatureForError ());
 308                                 return null;
 309                         }
 310
 311                         if (Arguments == null) {
 312                                 object o = att_cache [Type];
 313                                 if (o != null) {
 314                                         resolve_error = false;
 315                                         return (CustomAttributeBuilder)o;
 316                                 }
 317                         }
 318
 319                         ConstructorInfo ctor = ResolveArguments (ec);
 320                         if (ctor == null)
 321                                 return null;
 322
 323                         CustomAttributeBuilder cb;
 324
 325                         try {
 326                                 if (prop_info_arr != null || field_info_arr != null) {
 327                                         cb = new CustomAttributeBuilder (
 328                                                 ctor, pos_values,
 329                                                 prop_info_arr, prop_values_arr,
 330                                                 field_info_arr, field_values_arr);
 331                                 } else {
 332                                         cb = new CustomAttributeBuilder (
 333                                                 ctor, pos_values);
 334
 335                                         if (pos_values.Length == 0)
 336                                                 att_cache.Add (Type, cb);
 337                                 }
 338                         }
 339                         catch (Exception) {
 340                                 Error_AttributeArgumentNotValid (Location);
 341                                 return null;
 342                         }
 343
 344                         resolve_error = false;
 345                         return cb;
 346                 }
 347
 348                 protected virtual ConstructorInfo ResolveArguments (EmitContext ec)
 349                 {
 350                         // Now we extract the positional and named arguments
 351
 352                         ArrayList pos_args = null;
 353                         ArrayList named_args = null;
 354                         int pos_arg_count = 0;
 355                         int named_arg_count = 0;
 356
 357                         if (Arguments != null) {
 358                                 pos_args = (ArrayList) Arguments [0];
 359                                 if (pos_args != null)
 360                                         pos_arg_count = pos_args.Count;
 361                                 if (Arguments.Count > 1) {
 362                                         named_args = (ArrayList) Arguments [1];
 363                                         named_arg_count = named_args.Count;
 364                                 }
 365                         }
 366
 367                         pos_values = new object [pos_arg_count];
 368
 369                         //
 370                         // First process positional arguments
 371                         //
 372
 373                         int i;
 374                         for (i = 0; i < pos_arg_count; i++) {
 375                                 Argument a = (Argument) pos_args [i];
 376                                 Expression e;
 377
 378                                 if (!a.Resolve (ec, Location))
 379                                         return null;
 380
 381                                 e = a.Expr;
 382
 383                                 object val;
 384                                 if (!GetAttributeArgumentExpression (e, Location, a.Type, out val))
 385                                         return null;
 386
 387                                 pos_values [i] = val;
 388
 389                                 if (i == 0 && Type == TypeManager.attribute_usage_type && (int)val == 0) {
 390                                         Report.Error (591, Location, "Invalid value for argument to 'System.AttributeUsage' attribute");
 391                                         return null;
 392                                 }
 393                         }
 394
 395                         //
 396                         // Now process named arguments
 397                         //
 398
 399                         ArrayList field_infos = null;
 400                         ArrayList prop_infos  = null;
 401                         ArrayList field_values = null;
 402                         ArrayList prop_values = null;
 403                         Hashtable seen_names = null;
 404
 405                         if (named_arg_count > 0) {
 406                                 field_infos = new ArrayList ();
 407                                 prop_infos  = new ArrayList ();
 408                                 field_values = new ArrayList ();
 409                                 prop_values = new ArrayList ();
 410
 411                                 seen_names = new Hashtable();
 412                         }
 413
 414                         for (i = 0; i < named_arg_count; i++) {
 415                                 DictionaryEntry de = (DictionaryEntry) named_args [i];
 416                                 string member_name = (string) de.Key;
 417                                 Argument a  = (Argument) de.Value;
 418                                 Expression e;
 419
 420                                 if (seen_names.Contains(member_name)) {
 421                                         Report.Error(643, Location, "'" + member_name + "' duplicate named attribute argument");
 422                                         return null;
 423                                 }
 424                                 seen_names.Add(member_name, 1);
 425
 426                                 if (!a.Resolve (ec, Location))
 427                                         return null;
 428
 429                                 Expression member = Expression.MemberLookup (
 430                                         ec, Type, member_name,
 431                                         MemberTypes.Field | MemberTypes.Property,
 432                                         BindingFlags.Public | BindingFlags.Instance,
 433                                         Location);
 434
 435                                 if (member == null) {
 436                                         member = Expression.MemberLookup (ec, Type, member_name,
 437                                                 MemberTypes.Field | MemberTypes.Property, BindingFlags.NonPublic | BindingFlags.Instance,
 438                                                 Location);
 439
 440                                         if (member != null) {
 441                                                 Expression.ErrorIsInaccesible (Location, member.GetSignatureForError ());
 442                                                 return null;
 443                                         }
 444                                 }
 445
 446                                 if (member == null){
 447                                         Report.Error (117, Location, "`{0}' does not contain a definition for `{1}'",
 448                                                       Type, member_name);
 449                                         return null;
 450                                 }
 451
 452                                 if (!(member is PropertyExpr || member is FieldExpr)) {
 453                                         Error_InvalidNamedArgument (member_name);
 454                                         return null;
 455                                 }
 456
 457                                 e = a.Expr;
 458                                 if (e is TypeParameterExpr){
 459                                         Error_TypeParameterInAttribute (Location);
 460                                         return null;
 461                                 }
 462
 463                                 if (member is PropertyExpr) {
 464                                         PropertyExpr pe = (PropertyExpr) member;
 465                                         PropertyInfo pi = pe.PropertyInfo;
 466
 467                                         if (!pi.CanWrite || !pi.CanRead) {
 468                                                 Report.SymbolRelatedToPreviousError (pi);
 469                                                 Error_InvalidNamedArgument (member_name);
 470                                                 return null;
 471                                         }
 472
 473                                         if (!IsValidArgumentType (pi.PropertyType)) {
 474                                                 Report.SymbolRelatedToPreviousError (pi);
 475                                                 Error_InvalidNamedAgrumentType (member_name);
 476                                                 return null;
 477                                         }
 478
 479                                         object value;
 480                                         if (!GetAttributeArgumentExpression (e, Location, pi.PropertyType, out value))
 481                                                 return null;
 482
 483                                         prop_values.Add (value);
 484                                         prop_infos.Add (pi);
 485
 486                                 } else if (member is FieldExpr) {
 487                                         FieldExpr fe = (FieldExpr) member;
 488                                         FieldInfo fi = fe.FieldInfo;
 489
 490                                         if (fi.IsInitOnly) {
 491                                                 Error_InvalidNamedArgument (member_name);
 492                                                 return null;
 493                                         }
 494
 495                                         if (!IsValidArgumentType (fi.FieldType)) {
 496                                                 Report.SymbolRelatedToPreviousError (fi);
 497                                                 Error_InvalidNamedAgrumentType (member_name);
 498                                                 return null;
 499                                         }
 500
 501                                         object value;
 502                                         if (!GetAttributeArgumentExpression (e, Location, fi.FieldType, out value))
 503                                                 return null;
 504
 505                                         field_values.Add (value);
 506
 507                                         field_infos.Add (fi);
 508                                 }
 509                         }
 510
 511                         Expression mg = Expression.MemberLookup (
 512                                 ec, Type, ".ctor", MemberTypes.Constructor,
 513                                 BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly,
 514                                 Location);
 515
 516                         MethodBase constructor = Invocation.OverloadResolve (
 517                                 ec, (MethodGroupExpr) mg, pos_args, false, Location);
 518
 519                         if (constructor == null) {
 520                                 return null;
 521                         }
 522
 523
 524                         // Here we do the checks which should be done by corlib or by runtime.
 525                         // However Zoltan doesn't like it and every Mono compiler has to do it again.
 526
 527                         if (Type == TypeManager.guid_attr_type) {
 528                                 try {
 529                                         new Guid ((string)pos_values [0]);
 530                                 }
 531                                 catch (Exception e) {
 532                                         Error_AttributeEmitError (e.Message);
 533                                 }
 534                         }
 535 // TODO: reenable
 536 //                      if (Type == TypeManager.methodimpl_attr_type &&
 537 //                              pos_values.Length == 1 && ((Argument)pos_args [0]).Type == TypeManager.short_type &&
 538 //                              !System.Enum.IsDefined (TypeManager.method_impl_options, pos_values [0])) {
 539 //                                      Error_AttributeEmitError ("Incorrect argument value.");
 540 //                      }
 541
 542                         //
 543                         // Now we perform some checks on the positional args as they
 544                         // cannot be null for a constructor which expects a parameter
 545                         // of type object
 546                         //
 547
 548                         ParameterData pd = TypeManager.GetParameterData (constructor);
 549
 550                         int last_real_param = pd.Count;
 551                         if (pd.HasParams) {
 552                                 // When the params is not filled we need to put one
 553                                 if (last_real_param > pos_arg_count) {
 554                                         object [] new_pos_values = new object [pos_arg_count + 1];
 555                                         pos_values.CopyTo (new_pos_values, 0);
 556                                         new_pos_values [pos_arg_count] = new object [] {} ;
 557                                         pos_values = new_pos_values;
 558                                 }
 559                                 last_real_param--;
 560                         }
 561
 562                         for (int j = 0; j < pos_arg_count; ++j) {
 563                                 Argument a = (Argument) pos_args [j];
 564
 565                                 if (a.Expr is NullLiteral && pd.ParameterType (j) == TypeManager.object_type) {
 566                                         Error_AttributeArgumentNotValid (Location);
 567                                         return null;
 568                                 }
 569
 570                                 object value = pos_values [j];
 571                                 if (value != null && a.Type != value.GetType () && TypeManager.IsPrimitiveType (a.Type)) {
 572                                         bool fail;
 573                                         pos_values [j] = TypeManager.ChangeType (value, a.Type, out fail);
 574                                         if (fail) {
 575                                                 // TODO: Can failed ?
 576                                                 throw new NotImplementedException ();
 577                                         }
 578                                 }
 579
 580                                 if (j < last_real_param)
 581                                         continue;
 582
 583                                 if (j == last_real_param) {
 584                                         object [] array = new object [pos_arg_count - last_real_param];
 585                                         array [0] = pos_values [j];
 586                                         pos_values [j] = array;
 587                                         continue;
 588                                 }
 589
 590                                 object [] params_array = (object []) pos_values [last_real_param];
 591                                 params_array [j - last_real_param] = pos_values [j];
 592                         }
 593
 594                         // Adjust the size of the pos_values if it had params
 595                         if (last_real_param != pos_arg_count) {
 596                                 object [] new_pos_values = new object [last_real_param + 1];
 597                                 Array.Copy (pos_values, new_pos_values, last_real_param + 1);
 598                                 pos_values = new_pos_values;
 599                         }
 600
 601                         if (named_arg_count > 0) {
 602                                 prop_info_arr = new PropertyInfo [prop_infos.Count];
 603                                 field_info_arr = new FieldInfo [field_infos.Count];
 604                                 field_values_arr = new object [field_values.Count];
 605                                 prop_values_arr = new object [prop_values.Count];
 606
 607                                 field_infos.CopyTo  (field_info_arr, 0);
 608                                 field_values.CopyTo (field_values_arr, 0);
 609
 610                                 prop_values.CopyTo  (prop_values_arr, 0);
 611                                 prop_infos.CopyTo   (prop_info_arr, 0);
 612                         }
 613
 614                         return (ConstructorInfo) constructor;
 615                 }
 616
 617                 /// <summary>
 618                 ///   Get a string containing a list of valid targets for the attribute 'attr'
 619                 /// </summary>
 620                 public string GetValidTargets ()
 621                 {
 622                         StringBuilder sb = new StringBuilder ();
 623                         AttributeTargets targets = GetAttributeUsage (null).ValidOn;
 624
 625                         if ((targets & AttributeTargets.Assembly) != 0)
 626                                 sb.Append ("assembly, ");
 627
 628                         if ((targets & AttributeTargets.Module) != 0)
 629                                 sb.Append ("module, ");
 630
 631                         if ((targets & AttributeTargets.Class) != 0)
 632                                 sb.Append ("class, ");
 633
 634                         if ((targets & AttributeTargets.Struct) != 0)
 635                                 sb.Append ("struct, ");
 636
 637                         if ((targets & AttributeTargets.Enum) != 0)
 638                                 sb.Append ("enum, ");
 639
 640                         if ((targets & AttributeTargets.Constructor) != 0)
 641                                 sb.Append ("constructor, ");
 642
 643                         if ((targets & AttributeTargets.Method) != 0)
 644                                 sb.Append ("method, ");
 645
 646                         if ((targets & AttributeTargets.Property) != 0)
 647                                 sb.Append ("property, indexer, ");
 648
 649                         if ((targets & AttributeTargets.Field) != 0)
 650                                 sb.Append ("field, ");
 651
 652                         if ((targets & AttributeTargets.Event) != 0)
 653                                 sb.Append ("event, ");
 654
 655                         if ((targets & AttributeTargets.Interface) != 0)
 656                                 sb.Append ("interface, ");
 657
 658                         if ((targets & AttributeTargets.Parameter) != 0)
 659                                 sb.Append ("parameter, ");
 660
 661                         if ((targets & AttributeTargets.Delegate) != 0)
 662                                 sb.Append ("delegate, ");
 663
 664                         if ((targets & AttributeTargets.ReturnValue) != 0)
 665                                 sb.Append ("return, ");
 666
 667                         if ((targets & AttributeTargets.GenericParameter) != 0)
 668                                 sb.Append ("type parameter, ");
 669                         return sb.Remove (sb.Length - 2, 2).ToString ();
 670                 }
 671
 672                 /// <summary>
 673                 /// Returns AttributeUsage attribute for this type
 674                 /// </summary>
 675                 AttributeUsageAttribute GetAttributeUsage (EmitContext ec)
 676                 {
 677                         AttributeUsageAttribute ua = usage_attr_cache [Type] as AttributeUsageAttribute;
 678                         if (ua != null)
 679                                 return ua;
 680
 681                         Class attr_class = TypeManager.LookupClass (Type);
 682
 683                         if (attr_class == null) {
 684                                 object[] usage_attr = Type.GetCustomAttributes (TypeManager.attribute_usage_type, true);
 685                                 ua = (AttributeUsageAttribute)usage_attr [0];
 686                                 usage_attr_cache.Add (Type, ua);
 687                                 return ua;
 688                         }
 689
 690                         Attribute a = attr_class.OptAttributes == null
 691                                 ? null
 692                                 : attr_class.OptAttributes.Search (TypeManager.attribute_usage_type, attr_class.EmitContext);
 693
 694                         ua = a == null
 695                                 ? DefaultUsageAttribute
 696                                 : a.GetAttributeUsageAttribute (attr_class.EmitContext);
 697
 698                         usage_attr_cache.Add (Type, ua);
 699                         return ua;
 700                 }
 701
 702                 AttributeUsageAttribute GetAttributeUsageAttribute (EmitContext ec)
 703                 {
 704                         if (pos_values == null)
 705                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 706                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 707                                 Resolve (ec);
 708
 709                         if (resolve_error)
 710                                 return DefaultUsageAttribute;
 711
 712                         AttributeUsageAttribute usage_attribute = new AttributeUsageAttribute ((AttributeTargets)pos_values [0]);
 713
 714                         object field = GetPropertyValue ("AllowMultiple");
 715                         if (field != null)
 716                                 usage_attribute.AllowMultiple = (bool)field;
 717
 718                         field = GetPropertyValue ("Inherited");
 719                         if (field != null)
 720                                 usage_attribute.Inherited = (bool)field;
 721
 722                         return usage_attribute;
 723                 }
 724
 725                 /// <summary>
 726                 /// Returns custom name of indexer
 727                 /// </summary>
 728                 public string GetIndexerAttributeValue (EmitContext ec)
 729                 {
 730                         if (pos_values == null)
 731                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 732                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 733                                 Resolve (ec);
 734
 735                         if (resolve_error)
 736                                 return null;
 737
 738                         return pos_values [0] as string;
 739                 }
 740
 741                 /// <summary>
 742                 /// Returns condition of ConditionalAttribute
 743                 /// </summary>
 744                 public string GetConditionalAttributeValue (EmitContext ec)
 745                 {
 746                         if (pos_values == null)
 747                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 748                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 749                                 Resolve (ec);
 750
 751                         if (resolve_error)
 752                                 return null;
 753
 754                         return (string)pos_values [0];
 755                 }
 756
 757                 /// <summary>
 758                 /// Creates the instance of ObsoleteAttribute from this attribute instance
 759                 /// </summary>
 760                 public ObsoleteAttribute GetObsoleteAttribute (EmitContext ec)
 761                 {
 762                         if (pos_values == null)
 763                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 764                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 765                                 Resolve (ec);
 766
 767                         if (resolve_error)
 768                                 return null;
 769
 770                         if (pos_values == null || pos_values.Length == 0)
 771                                 return new ObsoleteAttribute ();
 772
 773                         if (pos_values.Length == 1)
 774                                 return new ObsoleteAttribute ((string)pos_values [0]);
 775
 776                         return new ObsoleteAttribute ((string)pos_values [0], (bool)pos_values [1]);
 777                 }
 778
 779                 /// <summary>
 780                 /// Returns value of CLSCompliantAttribute contructor parameter but because the method can be called
 781                 /// before ApplyAttribute. We need to resolve the arguments.
 782                 /// This situation occurs when class deps is differs from Emit order.
 783                 /// </summary>
 784                 public bool GetClsCompliantAttributeValue (EmitContext ec)
 785                 {
 786                         if (pos_values == null)
 787                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
 788                                 // But because a lot of attribute class code must be rewritten will be better to wait...
 789                                 Resolve (ec);
 790
 791                         if (resolve_error)
 792                                 return false;
 793
 794                         return (bool)pos_values [0];
 795                 }
 796
 797                 /// <summary>
 798                 /// Tests permitted SecurityAction for assembly or other types
 799                 /// </summary>
 800                 public bool CheckSecurityActionValidity (bool for_assembly)
 801                 {
 802                         SecurityAction action = GetSecurityActionValue ();
 803
 804                         switch (action) {
 805                         case SecurityAction.Demand:
 806                         case SecurityAction.Assert:
 807                         case SecurityAction.Deny:
 808                         case SecurityAction.PermitOnly:
 809                         case SecurityAction.LinkDemand:
 810                         case SecurityAction.InheritanceDemand:
 811                                 if (!for_assembly)
 812                                         return true;
 813                                 break;
 814
 815                         case SecurityAction.RequestMinimum:
 816                         case SecurityAction.RequestOptional:
 817                         case SecurityAction.RequestRefuse:
 818                                 if (for_assembly)
 819                                         return true;
 820                                 break;
 821
 822                         default:
 823                                 Error_AttributeEmitError ("SecurityAction is out of range X");
 824                                 return false;
 825                         }
 826
 827                         Error_AttributeEmitError (String.Concat ("SecurityAction '", action, "' is not valid for this declaration"));
 828                         return false;
 829                 }
 830
 831                 System.Security.Permissions.SecurityAction GetSecurityActionValue ()
 832                 {
 833                         return (SecurityAction)pos_values [0];
 834                 }
 835
 836                 /// <summary>
 837                 /// Creates instance of SecurityAttribute class and add result of CreatePermission method to permission table.
 838                 /// </summary>
 839                 /// <returns></returns>
 840                 public void ExtractSecurityPermissionSet (ListDictionary permissions)
 841                 {
 842                         Type orig_assembly_type = null;
 843
 844                         if (TypeManager.LookupDeclSpace (Type) != null) {
 845                                 if (!RootContext.StdLib) {
 846                                         orig_assembly_type = Type.GetType (Type.FullName);
 847                                 } else {
 848                                         string orig_version_path = Environment.GetEnvironmentVariable ("__SECURITY_BOOTSTRAP_DB");
 849                                         if (orig_version_path == null) {
 850                                                 Error_AttributeEmitError ("security custom attributes can not be referenced from defining assembly");
 851                                                 return;
 852                                         }
 853
 854                                         if (orig_sec_assembly == null) {
 855                                                 string file = Path.Combine (orig_version_path, Driver.OutputFile);
 856                                                 orig_sec_assembly = Assembly.LoadFile (file);
 857                                         }
 858
 859                                         orig_assembly_type = orig_sec_assembly.GetType (Type.FullName, true);
 860                                         if (orig_assembly_type == null) {
 861                                                 Report.Warning (-112, 1, Location, "Self-referenced security attribute `{0}' was not found in previous version of assembly");
 862                                                 return;
 863                                         }
 864                                 }
 865                         }
 866
 867                         SecurityAttribute sa;
 868                         // For all non-selfreferencing security attributes we can avoid all hacks
 869                         if (orig_assembly_type == null) {
 870                                 sa = (SecurityAttribute) Activator.CreateInstance (Type, pos_values);
 871
 872                                 if (prop_info_arr != null) {
 873                                         for (int i = 0; i < prop_info_arr.Length; ++i) {
 874                                                 PropertyInfo pi = prop_info_arr [i];
 875                                                 pi.SetValue (sa, prop_values_arr [i], null);
 876                                         }
 877                                 }
 878                         } else {
 879                                 // HACK: All security attributes have same ctor syntax
 880                                 sa = (SecurityAttribute) Activator.CreateInstance (orig_assembly_type, new object[] { GetSecurityActionValue () } );
 881
 882                                 // All types are from newly created assembly but for invocation with old one we need to convert them
 883                                 if (prop_info_arr != null) {
 884                                         for (int i = 0; i < prop_info_arr.Length; ++i) {
 885                                                 PropertyInfo emited_pi = prop_info_arr [i];
 886                                                 PropertyInfo pi = orig_assembly_type.GetProperty (emited_pi.Name, emited_pi.PropertyType);
 887
 888                                                 object old_instance = pi.PropertyType.IsEnum ?
 889                                                         System.Enum.ToObject (pi.PropertyType, prop_values_arr [i]) :
 890                                                         prop_values_arr [i];
 891
 892                                                 pi.SetValue (sa, old_instance, null);
 893                                         }
 894                                 }
 895                         }
 896
 897                         IPermission perm;
 898                         perm = sa.CreatePermission ();
 899                         SecurityAction action = GetSecurityActionValue ();
 900
 901                         // IS is correct because for corlib we are using an instance from old corlib
 902                         if (!(perm is System.Security.CodeAccessPermission)) {
 903                                 switch (action) {
 904                                         case SecurityAction.Demand:
 905                                                 action = (SecurityAction)13;
 906                                                 break;
 907                                         case SecurityAction.LinkDemand:
 908                                                 action = (SecurityAction)14;
 909                                                 break;
 910                                         case SecurityAction.InheritanceDemand:
 911                                                 action = (SecurityAction)15;
 912                                                 break;
 913                                 }
 914                         }
 915
 916                         PermissionSet ps = (PermissionSet)permissions [action];
 917                         if (ps == null) {
 918                                 if (sa is PermissionSetAttribute)
 919                                         ps = new PermissionSet (sa.Unrestricted ? PermissionState.Unrestricted : PermissionState.None);
 920                                 else
 921                                         ps = new PermissionSet (PermissionState.None);
 922
 923                                 permissions.Add (action, ps);
 924                         } else if (!ps.IsUnrestricted () && (sa is PermissionSetAttribute) && sa.Unrestricted) {
 925                                 ps = ps.Union (new PermissionSet (PermissionState.Unrestricted));
 926                                 permissions [action] = ps;
 927                         }
 928                         ps.AddPermission (perm);
 929                 }
 930
 931                 object GetValue (object value)
 932                 {
 933                         if (value is EnumConstant)
 934                                 return ((EnumConstant) value).GetValue ();
 935                         else
 936                                 return value;
 937                 }
 938
 939                 object GetPropertyValue (string name)
 940                 {
 941                         if (prop_info_arr == null)
 942                                 return null;
 943
 944                         for (int i = 0; i < prop_info_arr.Length; ++i) {
 945                                 if (prop_info_arr [i].Name == name)
 946                                         return prop_values_arr [i];
 947                         }
 948
 949                         return null;
 950                 }
 951
 952                 object GetFieldValue (string name)
 953                 {
 954                         int i;
 955                         if (field_info_arr == null)
 956                                 return null;
 957                         i = 0;
 958                         foreach (FieldInfo fi in field_info_arr) {
 959                                 if (fi.Name == name)
 960                                         return GetValue (field_values_arr [i]);
 961                                 i++;
 962                         }
 963                         return null;
 964                 }
 965
 966                 public UnmanagedMarshal GetMarshal (Attributable attr)
 967                 {
 968                         UnmanagedType UnmanagedType = (UnmanagedType)System.Enum.Parse (typeof (UnmanagedType), pos_values [0].ToString ());
 969
 970                         object value = GetFieldValue ("SizeParamIndex");
 971                         if (value != null && UnmanagedType != UnmanagedType.LPArray) {
 972                                 Error_AttributeEmitError ("SizeParamIndex field is not valid for the specified unmanaged type");
 973                                 return null;
 974                         }
 975
 976                         object o = GetFieldValue ("ArraySubType");
 977                         UnmanagedType array_sub_type = o == null ? UnmanagedType.I4 : (UnmanagedType) o;
 978
 979                         switch (UnmanagedType) {
 980                         case UnmanagedType.CustomMarshaler: {
 981                                 MethodInfo define_custom = typeof (UnmanagedMarshal).GetMethod ("DefineCustom",
 982                                                                        BindingFlags.Static | BindingFlags.Public);
 983                                 if (define_custom == null) {
 984                                         Report.RuntimeMissingSupport (Location, "set marshal info");
 985                                         return null;
 986                                 }
 987
 988                                 object [] args = new object [4];
 989                                 args [0] = GetFieldValue ("MarshalTypeRef");
 990                                 args [1] = GetFieldValue ("MarshalCookie");
 991                                 args [2] = GetFieldValue ("MarshalType");
 992                                 args [3] = Guid.Empty;
 993                                 return (UnmanagedMarshal) define_custom.Invoke (null, args);
 994                         }
 995                         case UnmanagedType.LPArray: {
 996                                 object size_const = GetFieldValue ("SizeConst");
 997                                 object size_param_index = GetFieldValue ("SizeParamIndex");
 998
 999                                 if ((size_const != null) || (size_param_index != null)) {
1000                                         MethodInfo define_array = typeof (UnmanagedMarshal).GetMethod ("DefineLPArrayInternal", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
1001                                         if (define_array == null) {
1002                                                 Report.RuntimeMissingSupport (Location, "set marshal info");
1003                                                 return null;
1004                                         }
1005
1006                                         object [] args = new object [3];
1007                                         args [0] = array_sub_type;
1008                                         args [1] = size_const == null ? -1 : size_const;
1009                                         args [2] = size_param_index == null ? -1 : size_param_index;
1010                                         return (UnmanagedMarshal) define_array.Invoke (null, args);
1011                                 }
1012                                 else
1013                                         return UnmanagedMarshal.DefineLPArray (array_sub_type);
1014                         }
1015                         case UnmanagedType.SafeArray:
1016                                 return UnmanagedMarshal.DefineSafeArray (array_sub_type);
1017
1018                         case UnmanagedType.ByValArray:
1019                                 FieldMember fm = attr as FieldMember;
1020                                 if (fm == null) {
1021                                         Error_AttributeEmitError ("Specified unmanaged type is only valid on fields");
1022                                         return null;
1023                                 }
1024                                 return UnmanagedMarshal.DefineByValArray ((int) GetFieldValue ("SizeConst"));
1025
1026                         case UnmanagedType.ByValTStr:
1027                                 return UnmanagedMarshal.DefineByValTStr ((int) GetFieldValue ("SizeConst"));
1028
1029                         default:
1030                                 return UnmanagedMarshal.DefineUnmanagedMarshal (UnmanagedType);
1031                         }
1032                 }
1033
1034                 public CharSet GetCharSetValue ()
1035                 {
1036                         return (CharSet)System.Enum.Parse (typeof (CharSet), pos_values [0].ToString ());
1037                 }
1038
1039                 public MethodImplOptions GetMethodImplOptions ()
1040                 {
1041                         return (MethodImplOptions)System.Enum.Parse (typeof (MethodImplOptions), pos_values [0].ToString ());
1042                 }
1043
1044                 public LayoutKind GetLayoutKindValue ()
1045                 {
1046                         return (LayoutKind)System.Enum.Parse (typeof (LayoutKind), pos_values [0].ToString ());
1047                 }
1048
1049                 /// <summary>
1050                 /// Emit attribute for Attributable symbol
1051                 /// </summary>
1052                 public void Emit (EmitContext ec, Attributable ias, ListDictionary emitted_attr)
1053                 {
1054                         CustomAttributeBuilder cb = Resolve (ec);
1055                         if (cb == null)
1056                                 return;
1057
1058                         AttributeUsageAttribute usage_attr = GetAttributeUsage (ec);
1059                         if ((usage_attr.ValidOn & Target) == 0) {
1060                                 Report.Error (592, Location, "Attribute `{0}' is not valid on this declaration type. It is valid on `{1}' declarations only",
1061                                         GetSignatureForError (), GetValidTargets ());
1062                                 return;
1063                         }
1064
1065                         try {
1066                                 ias.ApplyAttributeBuilder (this, cb);
1067                         }
1068                         catch (Exception e) {
1069                                 Error_AttributeEmitError (e.Message);
1070                                 return;
1071                         }
1072
1073                         if (!usage_attr.AllowMultiple) {
1074                                 ArrayList emitted_targets = (ArrayList)emitted_attr [Type];
1075                                 if (emitted_targets == null) {
1076                                         emitted_targets = new ArrayList ();
1077                                         emitted_attr.Add (Type, emitted_targets);
1078                                 } else if (emitted_targets.Contains (Target)) {
1079                                         Report.Error (579, Location, "Duplicate `{0}' attribute", GetSignatureForError ());
1080                                         return;
1081                                 }
1082                                 emitted_targets.Add (Target);
1083                         }
1084
1085                         if (!RootContext.VerifyClsCompliance)
1086                                 return;
1087
1088                         // Here we are testing attribute arguments for array usage (error 3016)
1089                         if (ias.IsClsComplianceRequired (ec.DeclSpace)) {
1090                                 if (Arguments == null)
1091                                         return;
1092
1093                                 ArrayList pos_args = (ArrayList) Arguments [0];
1094                                 if (pos_args != null) {
1095                                         foreach (Argument arg in pos_args) {
1096                                                 // Type is undefined (was error 246)
1097                                                 if (arg.Type == null)
1098                                                         return;
1099
1100                                                 if (arg.Type.IsArray) {
1101                                                         Report.Error (3016, Location, "Arrays as attribute arguments are not CLS-compliant");
1102                                                         return;
1103                                                 }
1104                                         }
1105                                 }
1106
1107                                 if (Arguments.Count < 2)
1108                                         return;
1109
1110                                 ArrayList named_args = (ArrayList) Arguments [1];
1111                                 foreach (DictionaryEntry de in named_args) {
1112                                         Argument arg  = (Argument) de.Value;
1113
1114                                         // Type is undefined (was error 246)
1115                                         if (arg.Type == null)
1116                                                 return;
1117
1118                                         if (arg.Type.IsArray) {
1119                                                 Report.Error (3016, Location, "Arrays as attribute arguments are not CLS-compliant");
1120                                                 return;
1121                                         }
1122                                 }
1123                         }
1124                 }
1125
1126                 public MethodBuilder DefinePInvokeMethod (EmitContext ec, TypeBuilder builder, string name,
1127                                                           MethodAttributes flags, Type ret_type, Type [] param_types)
1128                 {
1129                         if (pos_values == null)
1130                                 // TODO: It is not neccessary to call whole Resolve (ApplyAttribute does it now) we need only ctor args.
1131                                 // But because a lot of attribute class code must be rewritten will be better to wait...
1132                                 Resolve (ec);
1133
1134                         if (resolve_error)
1135                                 return null;
1136
1137                         string dll_name = (string)pos_values [0];
1138
1139                         // Default settings
1140                         CallingConvention cc = CallingConvention.Winapi;
1141                         CharSet charset = CodeGen.Module.DefaultCharSet;
1142                         bool preserve_sig = true;
1143                         string entry_point = name;
1144                         bool best_fit_mapping = false;
1145                         bool throw_on_unmappable = false;
1146                         bool exact_spelling = false;
1147                         bool set_last_error = false;
1148
1149                         bool best_fit_mapping_set = false;
1150                         bool throw_on_unmappable_set = false;
1151                         bool exact_spelling_set = false;
1152                         bool set_last_error_set = false;
1153
1154                         MethodInfo set_best_fit = null;
1155                         MethodInfo set_throw_on = null;
1156                         MethodInfo set_exact_spelling = null;
1157                         MethodInfo set_set_last_error = null;
1158
1159                         if (field_info_arr != null) {
1160
1161                                 for (int i = 0; i < field_info_arr.Length; i++) {
1162                                         switch (field_info_arr [i].Name) {
1163                                                 case "BestFitMapping":
1164                                                         best_fit_mapping = (bool) field_values_arr [i];
1165                                                         best_fit_mapping_set = true;
1166                                                         break;
1167                                                 case "CallingConvention":
1168                                                         cc = (CallingConvention) field_values_arr [i];
1169                                                         break;
1170                                                 case "CharSet":
1171                                                         charset = (CharSet) field_values_arr [i];
1172                                                         break;
1173                                                 case "EntryPoint":
1174                                                         entry_point = (string) field_values_arr [i];
1175                                                         break;
1176                                                 case "ExactSpelling":
1177                                                         exact_spelling = (bool) field_values_arr [i];
1178                                                         exact_spelling_set = true;
1179                                                         break;
1180                                                 case "PreserveSig":
1181                                                         preserve_sig = (bool) field_values_arr [i];
1182                                                         break;
1183                                                 case "SetLastError":
1184                                                         set_last_error = (bool) field_values_arr [i];
1185                                                         set_last_error_set = true;
1186                                                         break;
1187                                                 case "ThrowOnUnmappableChar":
1188                                                         throw_on_unmappable = (bool) field_values_arr [i];
1189                                                         throw_on_unmappable_set = true;
1190                                                         break;
1191                                                 default:
1192                                                         throw new InternalErrorException (field_info_arr [i].ToString ());
1193                                         }
1194                                 }
1195                         }
1196
1197                         if (throw_on_unmappable_set || best_fit_mapping_set || exact_spelling_set || set_last_error_set) {
1198                                 set_best_fit = typeof (MethodBuilder).GetMethod ("set_BestFitMapping", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
1199                                 set_throw_on = typeof (MethodBuilder).GetMethod ("set_ThrowOnUnmappableChar", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
1200                                 set_exact_spelling = typeof (MethodBuilder).GetMethod ("set_ExactSpelling", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
1201                                 set_set_last_error = typeof (MethodBuilder).GetMethod ("set_SetLastError", BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
1202
1203                                 if ((set_best_fit == null) || (set_throw_on == null) || (set_exact_spelling == null) || (set_set_last_error == null)) {
1204                                         Report.Error (-1, Location,
1205                                                                   "The ThrowOnUnmappableChar, BestFitMapping, SetLastError, and ExactSpelling attributes can only be emitted when running on the mono runtime.");
1206                                         return null;
1207                                 }
1208                         }
1209
1210                         try {
1211                                 MethodBuilder mb = builder.DefinePInvokeMethod (
1212                                         name, dll_name, entry_point, flags | MethodAttributes.HideBySig | MethodAttributes.PinvokeImpl,
1213                                         CallingConventions.Standard, ret_type, param_types, cc, charset);
1214
1215                                 if (preserve_sig)
1216                                         mb.SetImplementationFlags (MethodImplAttributes.PreserveSig);
1217
1218                                 if (throw_on_unmappable_set)
1219                                         set_throw_on.Invoke (mb, 0, null, new object [] { throw_on_unmappable }, null);
1220                                 if (best_fit_mapping_set)
1221                                         set_best_fit.Invoke (mb, 0, null, new object [] { best_fit_mapping }, null);
1222                                 if (exact_spelling_set)
1223                                         set_exact_spelling.Invoke  (mb, 0, null, new object [] { exact_spelling }, null);
1224                                 if (set_last_error_set)
1225                                         set_set_last_error.Invoke  (mb, 0, null, new object [] { set_last_error }, null);
1226
1227                                 return mb;
1228                         }
1229                         catch (ArgumentException e) {
1230                                 Error_AttributeEmitError (e.Message);
1231                                 return null;
1232                         }
1233                 }
1234
1235                 private Expression GetValue ()
1236                 {
1237                         if ((Arguments == null) || (Arguments.Count < 1))
1238                                 return null;
1239                         ArrayList al = (ArrayList) Arguments [0];
1240                         if ((al == null) || (al.Count < 1))
1241                                 return null;
1242                         Argument arg = (Argument) al [0];
1243                         if ((arg == null) || (arg.Expr == null))
1244                                 return null;
1245                         return arg.Expr;
1246                 }
1247
1248                 public string GetString ()
1249                 {
1250                         Expression e = GetValue ();
1251                         if (e is StringLiteral)
1252                                 return (e as StringLiteral).Value;
1253                         return null;
1254                 }
1255
1256                 public bool GetBoolean ()
1257                 {
1258                         Expression e = GetValue ();
1259                         if (e is BoolLiteral)
1260                                 return (e as BoolLiteral).Value;
1261                         return false;
1262                 }
1263         }
1264
1265
1266         /// <summary>
1267         /// For global attributes (assembly, module) we need special handling.
1268         /// Attributes can be located in the several files
1269         /// </summary>
1270         public class GlobalAttribute: Attribute
1271         {
1272                 public readonly NamespaceEntry ns;
1273
1274                 public GlobalAttribute (TypeContainer container, string target,
1275                                         Expression left_expr, string identifier, ArrayList args, Location loc):
1276                         base (target, left_expr, identifier, args, loc)
1277                 {
1278                         ns = container.NamespaceEntry;
1279                 }
1280
1281                 void Enter ()
1282                 {
1283                         // RootContext.Tree.Types has a single NamespaceEntry which gets overwritten
1284                         // each time a new file is parsed.  However, we need to use the NamespaceEntry
1285                         // in effect where the attribute was used.  Since code elsewhere cannot assume
1286                         // that the NamespaceEntry is right, just overwrite it.
1287                         //
1288                         // Precondition: RootContext.Tree.Types == null
1289
1290                         if (RootContext.Tree.Types.NamespaceEntry != null)
1291                                 throw new InternalErrorException (Location + " non-null NamespaceEntry");
1292
1293                         RootContext.Tree.Types.NamespaceEntry = ns;
1294                 }
1295
1296                 void Leave ()
1297                 {
1298                         RootContext.Tree.Types.NamespaceEntry = null;
1299                 }
1300
1301                 protected override FullNamedExpression ResolveAsTypeStep (Expression expr, EmitContext ec, bool silent)
1302                 {
1303                         try {
1304                                 Enter ();
1305                                 return base.ResolveAsTypeStep (expr, ec, silent);
1306                         }
1307                         finally {
1308                                 Leave ();
1309                         }
1310                 }
1311
1312
1313                 protected override FullNamedExpression ResolveAsTypeTerminal (Expression expr, EmitContext ec, bool silent)
1314                 {
1315                         try {
1316                                 Enter ();
1317                                 return base.ResolveAsTypeTerminal (expr, ec, silent);
1318                         }
1319                         finally {
1320                                 Leave ();
1321                         }
1322                 }
1323
1324                 protected override ConstructorInfo ResolveArguments (EmitContext ec)
1325                 {
1326                         try {
1327                                 Enter ();
1328                                 return base.ResolveArguments (ec);
1329                         }
1330                         finally {
1331                                 Leave ();
1332                         }
1333                 }
1334         }
1335
1336         public class Attributes {
1337                 public ArrayList Attrs;
1338
1339                 public Attributes (Attribute a)
1340                 {
1341                         Attrs = new ArrayList ();
1342                         Attrs.Add (a);
1343                 }
1344
1345                 public Attributes (ArrayList attrs)
1346                 {
1347                         Attrs = attrs;
1348                 }
1349
1350                 public void AddAttributes (ArrayList attrs)
1351                 {
1352                         Attrs.AddRange (attrs);
1353                 }
1354
1355                 /// <summary>
1356                 /// Checks whether attribute target is valid for the current element
1357                 /// </summary>
1358                 public bool CheckTargets (Attributable member)
1359                 {
1360                         string[] valid_targets = member.ValidAttributeTargets;
1361                         foreach (Attribute a in Attrs) {
1362                                 if (a.ExplicitTarget == null || a.ExplicitTarget == valid_targets [0]) {
1363                                         a.Target = member.AttributeTargets;
1364                                         continue;
1365                                 }
1366
1367                                 // TODO: we can skip the first item
1368                                 if (((IList) valid_targets).Contains (a.ExplicitTarget)) {
1369                                         switch (a.ExplicitTarget) {
1370                                                 case "return": a.Target = AttributeTargets.ReturnValue; continue;
1371                                                 case "param": a.Target = AttributeTargets.Parameter; continue;
1372                                                 case "field": a.Target = AttributeTargets.Field; continue;
1373                                                 case "method": a.Target = AttributeTargets.Method; continue;
1374                                                 case "property": a.Target = AttributeTargets.Property; continue;
1375                                         }
1376                                         throw new InternalErrorException ("Unknown explicit target: " + a.ExplicitTarget);
1377                                 }
1378
1379                                 StringBuilder sb = new StringBuilder ();
1380                                 foreach (string s in valid_targets) {
1381                                         sb.Append (s);
1382                                         sb.Append (", ");
1383                                 }
1384                                 sb.Remove (sb.Length - 2, 2);
1385                                 Report.Error (657, a.Location, "`{0}' is not a valid attribute location for this declaration. Valid attribute locations for this declaration are `{1}'", a.ExplicitTarget, sb.ToString ());
1386                                 return false;
1387                         }
1388                         return true;
1389                 }
1390
1391                 public Attribute Search (Type t, EmitContext ec)
1392                 {
1393                         foreach (Attribute a in Attrs) {
1394                                 if (a.ResolveType (ec) == t)
1395                                         return a;
1396                         }
1397                         return null;
1398                 }
1399
1400                 /// <summary>
1401                 /// Returns all attributes of type 't'. Use it when attribute is AllowMultiple = true
1402                 /// </summary>
1403                 public Attribute[] SearchMulti (Type t, EmitContext ec)
1404                 {
1405                         ArrayList ar = null;
1406
1407                         foreach (Attribute a in Attrs) {
1408                                 if (a.ResolveType (ec) == t) {
1409                                         if (ar == null)
1410                                                 ar = new ArrayList ();
1411                                         ar.Add (a);
1412                                 }
1413                         }
1414
1415                         return ar == null ? null : ar.ToArray (typeof (Attribute)) as Attribute[];
1416                 }
1417
1418                 public void Emit (EmitContext ec, Attributable ias)
1419                 {
1420                         CheckTargets (ias);
1421
1422                         ListDictionary ld = new ListDictionary ();
1423
1424                         foreach (Attribute a in Attrs)
1425                                 a.Emit (ec, ias, ld);
1426                 }
1427
1428                 public bool Contains (Type t, EmitContext ec)
1429                 {
1430                         return Search (t, ec) != null;
1431                 }
1432         }
1433
1434         /// <summary>
1435         /// Helper class for attribute verification routine.
1436         /// </summary>
1437         sealed class AttributeTester
1438         {
1439                 static PtrHashtable analyzed_types = new PtrHashtable ();
1440                 static PtrHashtable analyzed_types_obsolete = new PtrHashtable ();
1441                 static PtrHashtable analyzed_member_obsolete = new PtrHashtable ();
1442                 static PtrHashtable analyzed_method_excluded = new PtrHashtable ();
1443
1444                 static PtrHashtable fixed_buffer_cache = new PtrHashtable ();
1445
1446                 static object TRUE = new object ();
1447                 static object FALSE = new object ();
1448
1449                 private AttributeTester ()
1450                 {
1451                 }
1452
1453                 public enum Result {
1454                         Ok,
1455                         RefOutArrayError,
1456                         ArrayArrayError
1457                 }
1458
1459                 /// <summary>
1460                 /// Returns true if parameters of two compared methods are CLS-Compliant.
1461                 /// It tests differing only in ref or out, or in array rank.
1462                 /// </summary>
1463                 public static Result AreOverloadedMethodParamsClsCompliant (Type[] types_a, Type[] types_b)
1464                 {
1465                         if (types_a == null || types_b == null)
1466                                 return Result.Ok;
1467
1468                         if (types_a.Length != types_b.Length)
1469                                 return Result.Ok;
1470
1471                         Result result = Result.Ok;
1472                         for (int i = 0; i < types_b.Length; ++i) {
1473                                 Type aType = types_a [i];
1474                                 Type bType = types_b [i];
1475
1476                                 if (aType.IsArray && bType.IsArray) {
1477                                         Type a_el_type = aType.GetElementType ();
1478                                         Type b_el_type = bType.GetElementType ();
1479                                         if (aType.GetArrayRank () != bType.GetArrayRank () && a_el_type == b_el_type) {
1480                                                 result = Result.RefOutArrayError;
1481                                                 continue;
1482                                         }
1483
1484                                         if (a_el_type.IsArray || b_el_type.IsArray) {
1485                                                 result = Result.ArrayArrayError;
1486                                                 continue;
1487                                         }
1488                                 }
1489
1490                                 Type aBaseType = aType;
1491                                 bool is_either_ref_or_out = false;
1492
1493                                 if (aType.IsByRef || aType.IsPointer) {
1494                                         aBaseType = aType.GetElementType ();
1495                                         is_either_ref_or_out = true;
1496                                 }
1497
1498                                 Type bBaseType = bType;
1499                                 if (bType.IsByRef || bType.IsPointer)
1500                                 {
1501                                         bBaseType = bType.GetElementType ();
1502                                         is_either_ref_or_out = !is_either_ref_or_out;
1503                                 }
1504
1505                                 if (aBaseType != bBaseType)
1506                                         return Result.Ok;
1507
1508                                 if (is_either_ref_or_out)
1509                                         result = Result.RefOutArrayError;
1510                         }
1511                         return result;
1512                 }
1513
1514                 /// <summary>
1515                 /// Goes through all parameters and test if they are CLS-Compliant.
1516                 /// </summary>
1517                 public static bool AreParametersCompliant (Parameter[] fixedParameters, Location loc)
1518                 {
1519                         if (fixedParameters == null)
1520                                 return true;
1521
1522                         foreach (Parameter arg in fixedParameters) {
1523                                 if (!AttributeTester.IsClsCompliant (arg.ParameterType)) {
1524                                         Report.Error (3001, loc, "Argument type `{0}' is not CLS-compliant", arg.GetSignatureForError ());
1525                                         return false;
1526                                 }
1527                         }
1528                         return true;
1529                 }
1530
1531
1532                 /// <summary>
1533                 /// This method tests the CLS compliance of external types. It doesn't test type visibility.
1534                 /// </summary>
1535                 public static bool IsClsCompliant (Type type)
1536                 {
1537                         if (type == null)
1538                                 return true;
1539
1540                         object type_compliance = analyzed_types[type];
1541                         if (type_compliance != null)
1542                                 return type_compliance == TRUE;
1543
1544                         if (type.IsPointer) {
1545                                 analyzed_types.Add (type, null);
1546                                 return false;
1547                         }
1548
1549                         bool result;
1550                         if (type.IsArray || type.IsByRef)       {
1551                                 result = IsClsCompliant (TypeManager.GetElementType (type));
1552                         } else {
1553                                 result = AnalyzeTypeCompliance (type);
1554                         }
1555                         analyzed_types.Add (type, result ? TRUE : FALSE);
1556                         return result;
1557                 }
1558
1559                 /// <summary>
1560                 /// Returns IFixedBuffer implementation if field is fixed buffer else null.
1561                 /// </summary>
1562                 public static IFixedBuffer GetFixedBuffer (FieldInfo fi)
1563                 {
1564                         FieldBase fb = TypeManager.GetField (fi);
1565                         if (fb != null) {
1566                                 return fb as IFixedBuffer;
1567                         }
1568
1569                         object o = fixed_buffer_cache [fi];
1570                         if (o == null) {
1571                                 if (System.Attribute.GetCustomAttribute (fi, TypeManager.fixed_buffer_attr_type) == null) {
1572                                         fixed_buffer_cache.Add (fi, FALSE);
1573                                         return null;
1574                                 }
1575
1576                                 IFixedBuffer iff = new FixedFieldExternal (fi);
1577                                 fixed_buffer_cache.Add (fi, iff);
1578                                 return iff;
1579                         }
1580
1581                         if (o == FALSE)
1582                                 return null;
1583
1584                         return (IFixedBuffer)o;
1585                 }
1586
1587                 public static void VerifyModulesClsCompliance ()
1588                 {
1589                         Module[] modules = TypeManager.Modules;
1590                         if (modules == null)
1591                                 return;
1592
1593                         // The first module is generated assembly
1594                         for (int i = 1; i < modules.Length; ++i) {
1595                                 Module module = modules [i];
1596                                 if (!IsClsCompliant (module)) {
1597                                         Report.Error (3013, "Added modules must be marked with the CLSCompliant attribute to match the assembly", module.Name);
1598                                         return;
1599                                 }
1600                         }
1601                 }
1602
1603                 public static Type GetImportedIgnoreCaseClsType (string name)
1604                 {
1605                         foreach (Assembly a in TypeManager.GetAssemblies ()) {
1606                                 Type t = a.GetType (name, false, true);
1607                                 if (t == null)
1608                                         continue;
1609
1610                                 if (IsClsCompliant (t))
1611                                         return t;
1612                         }
1613                         return null;
1614                 }
1615
1616                 static bool IsClsCompliant (ICustomAttributeProvider attribute_provider)
1617                 {
1618                         object[] CompliantAttribute = attribute_provider.GetCustomAttributes (TypeManager.cls_compliant_attribute_type, false);
1619                         if (CompliantAttribute.Length == 0)
1620                                 return false;
1621
1622                         return ((CLSCompliantAttribute)CompliantAttribute[0]).IsCompliant;
1623                 }
1624
1625                 static bool AnalyzeTypeCompliance (Type type)
1626                 {
1627                         if (type.IsGenericInstance)
1628                                 type = type.GetGenericTypeDefinition ();
1629                         DeclSpace ds = TypeManager.LookupDeclSpace (type);
1630                         if (ds != null)
1631                                 return ds.IsClsComplianceRequired (ds);
1632
1633                         if (type.IsGenericParameter)
1634                                 return true;
1635
1636                         object[] CompliantAttribute = type.GetCustomAttributes (TypeManager.cls_compliant_attribute_type, false);
1637                         if (CompliantAttribute.Length == 0)
1638                                 return IsClsCompliant (type.Assembly);
1639
1640                         return ((CLSCompliantAttribute)CompliantAttribute[0]).IsCompliant;
1641                 }
1642
1643                 /// <summary>
1644                 /// Returns instance of ObsoleteAttribute when type is obsolete
1645                 /// </summary>
1646                 public static ObsoleteAttribute GetObsoleteAttribute (Type type)
1647                 {
1648                         object type_obsolete = analyzed_types_obsolete [type];
1649                         if (type_obsolete == FALSE)
1650                                 return null;
1651
1652                         if (type_obsolete != null)
1653                                 return (ObsoleteAttribute)type_obsolete;
1654
1655                         ObsoleteAttribute result = null;
1656                         if (type.IsByRef || type.IsArray || type.IsPointer) {
1657                                 result = GetObsoleteAttribute (TypeManager.GetElementType (type));
1658                         } else if (type.IsGenericParameter || type.IsGenericInstance)
1659                                 return null;
1660                         else {
1661                                 DeclSpace type_ds = TypeManager.LookupDeclSpace (type);
1662
1663                                 // Type is external, we can get attribute directly
1664                                 if (type_ds == null) {
1665                                         object[] attribute = type.GetCustomAttributes (TypeManager.obsolete_attribute_type, false);
1666                                         if (attribute.Length == 1)
1667                                                 result = (ObsoleteAttribute)attribute [0];
1668                                 } else {
1669                                         result = type_ds.GetObsoleteAttribute (type_ds);
1670                                 }
1671                         }
1672
1673                         analyzed_types_obsolete.Add (type, result == null ? FALSE : result);
1674                         return result;
1675                 }
1676
1677                 /// <summary>
1678                 /// Returns instance of ObsoleteAttribute when method is obsolete
1679                 /// </summary>
1680                 public static ObsoleteAttribute GetMethodObsoleteAttribute (MethodBase mb)
1681                 {
1682                         IMethodData mc = TypeManager.GetMethod (mb);
1683                         if (mc != null)
1684                                 return mc.GetObsoleteAttribute ();
1685
1686                         // compiler generated methods are not registered by AddMethod
1687                         if (mb.DeclaringType is TypeBuilder)
1688                                 return null;
1689
1690                         PropertyInfo pi = PropertyExpr.AccessorTable [mb] as PropertyInfo;
1691                         if (pi != null)
1692                                 return GetMemberObsoleteAttribute (pi);
1693
1694                         return GetMemberObsoleteAttribute (mb);
1695                 }
1696
1697                 /// <summary>
1698                 /// Returns instance of ObsoleteAttribute when member is obsolete
1699                 /// </summary>
1700                 public static ObsoleteAttribute GetMemberObsoleteAttribute (MemberInfo mi)
1701                 {
1702                         object type_obsolete = analyzed_member_obsolete [mi];
1703                         if (type_obsolete == FALSE)
1704                                 return null;
1705
1706                         if (type_obsolete != null)
1707                                 return (ObsoleteAttribute)type_obsolete;
1708
1709                         if ((mi.DeclaringType is TypeBuilder) || mi.DeclaringType.IsGenericInstance)
1710                                 return null;
1711
1712                         ObsoleteAttribute oa = System.Attribute.GetCustomAttribute (mi, TypeManager.obsolete_attribute_type, false) as ObsoleteAttribute;
1713                         analyzed_member_obsolete.Add (mi, oa == null ? FALSE : oa);
1714                         return oa;
1715                 }
1716
1717                 /// <summary>
1718                 /// Common method for Obsolete error/warning reporting.
1719                 /// </summary>
1720                 public static void Report_ObsoleteMessage (ObsoleteAttribute oa, string member, Location loc)
1721                 {
1722                         if (oa.IsError) {
1723                                 Report.Error (619, loc, "`{0}' is obsolete: `{1}'", member, oa.Message);
1724                                 return;
1725                         }
1726
1727                         if (oa.Message == null) {
1728                                 Report.Warning (612, loc, "`{0}' is obsolete", member);
1729                                 return;
1730                         }
1731                         if (RootContext.WarningLevel >= 2)
1732                                 Report.Warning (618, loc, "`{0}' is obsolete: `{1}'", member, oa.Message);
1733                 }
1734
1735                 public static bool IsConditionalMethodExcluded (MethodBase mb)
1736                 {
1737                         object excluded = analyzed_method_excluded [mb];
1738                         if (excluded != null)
1739                                 return excluded == TRUE ? true : false;
1740
1741                         if (mb.Mono_IsInflatedMethod)
1742                                 return false;
1743
1744                         ConditionalAttribute[] attrs = mb.GetCustomAttributes (TypeManager.conditional_attribute_type, true) as ConditionalAttribute[];
1745                         if (attrs.Length == 0) {
1746                                 analyzed_method_excluded.Add (mb, FALSE);
1747                                 return false;
1748                         }
1749
1750                         foreach (ConditionalAttribute a in attrs) {
1751                                 if (RootContext.AllDefines.Contains (a.ConditionString)) {
1752                                         analyzed_method_excluded.Add (mb, FALSE);
1753                                         return false;
1754                                 }
1755                         }
1756                         analyzed_method_excluded.Add (mb, TRUE);
1757                         return true;
1758                 }
1759
1760                 /// <summary>
1761                 /// Analyzes class whether it has attribute which has ConditionalAttribute
1762                 /// and its condition is not defined.
1763                 /// </summary>
1764                 public static bool IsAttributeExcluded (Type type)
1765                 {
1766                         if (!type.IsClass)
1767                                 return false;
1768
1769                         Class class_decl = TypeManager.LookupDeclSpace (type) as Class;
1770
1771                         // TODO: add caching
1772                         // TODO: merge all Type bases attribute caching to one cache to save memory
1773                         if (class_decl == null) {
1774                                 object[] attributes = type.GetCustomAttributes (TypeManager.conditional_attribute_type, false);
1775                                 foreach (ConditionalAttribute ca in attributes) {
1776                                         if (RootContext.AllDefines.Contains (ca.ConditionString))
1777                                                 return false;
1778                                 }
1779                                 return attributes.Length > 0;
1780                         }
1781
1782                         return class_decl.IsExcluded ();
1783                 }
1784         }
1785 }