mcs/gmcs/enum.cs

   1 //
   2 // enum.cs: Enum handling.
   3 //
   4 // Author: Miguel de Icaza (miguel@gnu.org)
   5 //         Ravi Pratap     (ravi@ximian.com)
   6 //
   7 // Licensed under the terms of the GNU GPL
   8 //
   9 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  10 //
  11
  12 using System;
  13 using System.Collections;
  14 using System.Reflection;
  15 using System.Reflection.Emit;
  16
  17 namespace Mono.CSharp {
  18
  19         /// <summary>
  20         ///   Enumeration container
  21         /// </summary>
  22         public class Enum : DeclSpace {
  23                 ArrayList ordered_enums;
  24
  25                 public Expression BaseType;
  26                 public Attributes  OptAttributes;
  27
  28                 public Type UnderlyingType;
  29
  30                 Hashtable member_to_location;
  31                 Hashtable member_to_attributes;
  32
  33                 //
  34                 // This is for members that have been defined
  35                 //
  36                 Hashtable member_to_value;
  37
  38                 //
  39                 // This is used to mark members we're currently defining
  40                 //
  41                 Hashtable in_transit;
  42
  43                 ArrayList field_builders;
  44
  45                 public const int AllowedModifiers =
  46                         Modifiers.NEW |
  47                         Modifiers.PUBLIC |
  48                         Modifiers.PROTECTED |
  49                         Modifiers.INTERNAL |
  50                         Modifiers.PRIVATE;
  51
  52                 public Enum (NamespaceEntry ns, TypeContainer parent, Expression type, int mod_flags,
  53                              string name, Attributes attrs, Location l)
  54                         : base (ns, parent, name, l)
  55                 {
  56                         this.BaseType = type;
  57                         ModFlags = Modifiers.Check (AllowedModifiers, mod_flags,
  58                                                     IsTopLevel ? Modifiers.INTERNAL : Modifiers.PRIVATE, l);
  59                         OptAttributes = attrs;
  60
  61                         ordered_enums = new ArrayList ();
  62                         member_to_location = new Hashtable ();
  63                         member_to_value = new Hashtable ();
  64                         in_transit = new Hashtable ();
  65                         field_builders = new ArrayList ();
  66                 }
  67
  68                 /// <summary>
  69                 ///   Adds @name to the enumeration space, with @expr
  70                 ///   being its definition.
  71                 /// </summary>
  72                 public AdditionResult AddEnumMember (string name, Expression expr, Location loc,
  73                                                      Attributes opt_attrs)
  74                 {
  75                         if (defined_names.Contains (name))
  76                                 return AdditionResult.NameExists;
  77
  78                         if (name == "value__") {
  79                                 Report.Error (76, loc, "An item in an enumeration can't have an identifier `value__'");
  80                                 return AdditionResult.Error;
  81                         }
  82
  83                         DefineName (name, expr);
  84
  85                         ordered_enums.Add (name);
  86                         member_to_location.Add (name, loc);
  87
  88                         if (member_to_attributes == null)
  89                                 member_to_attributes = new Hashtable ();
  90
  91                         member_to_attributes.Add (name, opt_attrs);
  92
  93                         return AdditionResult.Success;
  94                 }
  95
  96                 //
  97                 // This is used by corlib compilation: we map from our
  98                 // type to a type that is consumable by the DefineField
  99                 //
 100                 Type MapToInternalType (Type t)
 101                 {
 102                         if (t == TypeManager.int32_type)
 103                                 return typeof (int);
 104                         if (t == TypeManager.int64_type)
 105                                 return typeof (long);
 106                         if (t == TypeManager.uint32_type)
 107                                 return typeof (uint);
 108                         if (t == TypeManager.uint64_type)
 109                                 return typeof (ulong);
 110                         if (t == TypeManager.float_type)
 111                                 return typeof (float);
 112                         if (t == TypeManager.double_type)
 113                                 return typeof (double);
 114                         if (t == TypeManager.byte_type)
 115                                 return typeof (byte);
 116                         if (t == TypeManager.sbyte_type)
 117                                 return typeof (sbyte);
 118                         if (t == TypeManager.char_type)
 119                                 return typeof (char);
 120                         if (t == TypeManager.short_type)
 121                                 return typeof (short);
 122                         if (t == TypeManager.ushort_type)
 123                                 return typeof (ushort);
 124
 125                         throw new Exception ();
 126                 }
 127
 128                 public override TypeBuilder DefineType ()
 129                 {
 130                         if (TypeBuilder != null)
 131                                 return TypeBuilder;
 132
 133                         TypeAttributes attr = Modifiers.TypeAttr (ModFlags, IsTopLevel);
 134
 135                         attr |= TypeAttributes.Class | TypeAttributes.Sealed;
 136
 137                         UnderlyingType = ResolveType (BaseType, false, Location);
 138
 139                         if (UnderlyingType != TypeManager.int32_type &&
 140                             UnderlyingType != TypeManager.uint32_type &&
 141                             UnderlyingType != TypeManager.int64_type &&
 142                             UnderlyingType != TypeManager.uint64_type &&
 143                             UnderlyingType != TypeManager.short_type &&
 144                             UnderlyingType != TypeManager.ushort_type &&
 145                             UnderlyingType != TypeManager.byte_type  &&
 146                             UnderlyingType != TypeManager.char_type  &&
 147                             UnderlyingType != TypeManager.sbyte_type) {
 148                                 Report.Error (1008, Location,
 149                                               "Type byte, sbyte, short, char, ushort, int, uint, " +
 150                                               "long, or ulong expected (got: " +
 151                                               TypeManager.CSharpName (UnderlyingType) + ")");
 152                                 return null;
 153                         }
 154
 155                         if (IsTopLevel) {
 156                                 if (TypeManager.NamespaceClash (Name, Location))
 157                                         return null;
 158
 159                                 ModuleBuilder builder = CodeGen.ModuleBuilder;
 160
 161                                 TypeBuilder = builder.DefineType (Name, attr, TypeManager.enum_type);
 162                         } else {
 163                                 TypeBuilder builder = Parent.TypeBuilder;
 164
 165                                 TypeBuilder = builder.DefineNestedType (
 166                                         Basename, attr, TypeManager.enum_type);
 167                         }
 168
 169                         //
 170                         // Call MapToInternalType for corlib
 171                         //
 172                         TypeBuilder.DefineField ("value__", UnderlyingType,
 173                                                  FieldAttributes.Public | FieldAttributes.SpecialName
 174                                                  | FieldAttributes.RTSpecialName);
 175
 176                         TypeManager.AddEnumType (Name, TypeBuilder, this);
 177
 178                         return TypeBuilder;
 179                 }
 180
 181                 bool IsValidEnumConstant (Expression e)
 182                 {
 183                         if (!(e is Constant))
 184                                 return false;
 185
 186                         if (e is IntConstant || e is UIntConstant || e is LongConstant ||
 187                             e is ByteConstant || e is SByteConstant || e is ShortConstant ||
 188                             e is UShortConstant || e is ULongConstant || e is EnumConstant ||
 189                             e is CharConstant)
 190                                 return true;
 191                         else
 192                                 return false;
 193                 }
 194
 195                 object GetNextDefaultValue (object default_value)
 196                 {
 197                         if (UnderlyingType == TypeManager.int32_type) {
 198                                 int i = (int) default_value;
 199
 200                                 if (i < System.Int32.MaxValue)
 201                                         return ++i;
 202                                 else
 203                                         return null;
 204                         } else if (UnderlyingType == TypeManager.uint32_type) {
 205                                 uint i = (uint) default_value;
 206
 207                                 if (i < System.UInt32.MaxValue)
 208                                         return ++i;
 209                                 else
 210                                         return null;
 211                         } else if (UnderlyingType == TypeManager.int64_type) {
 212                                 long i = (long) default_value;
 213
 214                                 if (i < System.Int64.MaxValue)
 215                                         return ++i;
 216                                 else
 217                                         return null;
 218                         } else if (UnderlyingType == TypeManager.uint64_type) {
 219                                 ulong i = (ulong) default_value;
 220
 221                                 if (i < System.UInt64.MaxValue)
 222                                         return ++i;
 223                                 else
 224                                         return null;
 225                         } else if (UnderlyingType == TypeManager.short_type) {
 226                                 short i = (short) default_value;
 227
 228                                 if (i < System.Int16.MaxValue)
 229                                         return ++i;
 230                                 else
 231                                         return null;
 232                         } else if (UnderlyingType == TypeManager.ushort_type) {
 233                                 ushort i = (ushort) default_value;
 234
 235                                 if (i < System.UInt16.MaxValue)
 236                                         return ++i;
 237                                 else
 238                                         return null;
 239                         } else if (UnderlyingType == TypeManager.byte_type) {
 240                                 byte i = (byte) default_value;
 241
 242                                 if (i < System.Byte.MaxValue)
 243                                         return ++i;
 244                                 else
 245                                         return null;
 246                         } else if (UnderlyingType == TypeManager.sbyte_type) {
 247                                 sbyte i = (sbyte) default_value;
 248
 249                                 if (i < System.SByte.MaxValue)
 250                                         return ++i;
 251                                 else
 252                                         return null;
 253                         }
 254
 255                         return null;
 256                 }
 257
 258                 void Error_ConstantValueCannotBeConverted (object val, Location loc)
 259                 {
 260                         if (val is Constant)
 261                                 Report.Error (31, loc, "Constant value '" + ((Constant) val).AsString () +
 262                                               "' cannot be converted" +
 263                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 264                         else
 265                                 Report.Error (31, loc, "Constant value '" + val +
 266                                               "' cannot be converted" +
 267                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 268                         return;
 269                 }
 270
 271                 /// <summary>
 272                 ///  Determines if a standard implicit conversion exists from
 273                 ///  expr_type to target_type
 274                 /// </summary>
 275                 public static bool ImplicitConversionExists (Type expr_type, Type target_type)
 276                 {
 277                         expr_type = TypeManager.TypeToCoreType (expr_type);
 278
 279                         if (expr_type == TypeManager.void_type)
 280                                 return false;
 281
 282                         if (expr_type == target_type)
 283                                 return true;
 284
 285                         // First numeric conversions
 286
 287                         if (expr_type == TypeManager.sbyte_type){
 288                                 //
 289                                 // From sbyte to short, int, long, float, double.
 290                                 //
 291                                 if ((target_type == TypeManager.int32_type) ||
 292                                     (target_type == TypeManager.int64_type) ||
 293                                     (target_type == TypeManager.double_type) ||
 294                                     (target_type == TypeManager.float_type)  ||
 295                                     (target_type == TypeManager.short_type) ||
 296                                     (target_type == TypeManager.decimal_type))
 297                                         return true;
 298
 299                         } else if (expr_type == TypeManager.byte_type){
 300                                 //
 301                                 // From byte to short, ushort, int, uint, long, ulong, float, double
 302                                 //
 303                                 if ((target_type == TypeManager.short_type) ||
 304                                     (target_type == TypeManager.ushort_type) ||
 305                                     (target_type == TypeManager.int32_type) ||
 306                                     (target_type == TypeManager.uint32_type) ||
 307                                     (target_type == TypeManager.uint64_type) ||
 308                                     (target_type == TypeManager.int64_type) ||
 309                                     (target_type == TypeManager.float_type) ||
 310                                     (target_type == TypeManager.double_type) ||
 311                                     (target_type == TypeManager.decimal_type))
 312                                         return true;
 313
 314                         } else if (expr_type == TypeManager.short_type){
 315                                 //
 316                                 // From short to int, long, float, double
 317                                 //
 318                                 if ((target_type == TypeManager.int32_type) ||
 319                                     (target_type == TypeManager.int64_type) ||
 320                                     (target_type == TypeManager.double_type) ||
 321                                     (target_type == TypeManager.float_type) ||
 322                                     (target_type == TypeManager.decimal_type))
 323                                         return true;
 324
 325                         } else if (expr_type == TypeManager.ushort_type){
 326                                 //
 327                                 // From ushort to int, uint, long, ulong, float, double
 328                                 //
 329                                 if ((target_type == TypeManager.uint32_type) ||
 330                                     (target_type == TypeManager.uint64_type) ||
 331                                     (target_type == TypeManager.int32_type) ||
 332                                     (target_type == TypeManager.int64_type) ||
 333                                     (target_type == TypeManager.double_type) ||
 334                                     (target_type == TypeManager.float_type) ||
 335                                     (target_type == TypeManager.decimal_type))
 336                                         return true;
 337
 338                         } else if (expr_type == TypeManager.int32_type){
 339                                 //
 340                                 // From int to long, float, double
 341                                 //
 342                                 if ((target_type == TypeManager.int64_type) ||
 343                                     (target_type == TypeManager.double_type) ||
 344                                     (target_type == TypeManager.float_type) ||
 345                                     (target_type == TypeManager.decimal_type))
 346                                         return true;
 347
 348                         } else if (expr_type == TypeManager.uint32_type){
 349                                 //
 350                                 // From uint to long, ulong, float, double
 351                                 //
 352                                 if ((target_type == TypeManager.int64_type) ||
 353                                     (target_type == TypeManager.uint64_type) ||
 354                                     (target_type == TypeManager.double_type) ||
 355                                     (target_type == TypeManager.float_type) ||
 356                                     (target_type == TypeManager.decimal_type))
 357                                         return true;
 358
 359                         } else if ((expr_type == TypeManager.uint64_type) ||
 360                                    (expr_type == TypeManager.int64_type)) {
 361                                 //
 362                                 // From long/ulong to float, double
 363                                 //
 364                                 if ((target_type == TypeManager.double_type) ||
 365                                     (target_type == TypeManager.float_type) ||
 366                                     (target_type == TypeManager.decimal_type))
 367                                         return true;
 368
 369                         } else if (expr_type == TypeManager.char_type){
 370                                 //
 371                                 // From char to ushort, int, uint, long, ulong, float, double
 372                                 //
 373                                 if ((target_type == TypeManager.ushort_type) ||
 374                                     (target_type == TypeManager.int32_type) ||
 375                                     (target_type == TypeManager.uint32_type) ||
 376                                     (target_type == TypeManager.uint64_type) ||
 377                                     (target_type == TypeManager.int64_type) ||
 378                                     (target_type == TypeManager.float_type) ||
 379                                     (target_type == TypeManager.double_type) ||
 380                                     (target_type == TypeManager.decimal_type))
 381                                         return true;
 382
 383                         } else if (expr_type == TypeManager.float_type){
 384                                 //
 385                                 // float to double
 386                                 //
 387                                 if (target_type == TypeManager.double_type)
 388                                         return true;
 389                         }
 390
 391                         return false;
 392                 }
 393
 394                 //
 395                 // Horrible, horrible.  But there is no other way we can pass the EmitContext
 396                 // to the recursive definition triggered by the evaluation of a forward
 397                 // expression
 398                 //
 399                 static EmitContext current_ec = null;
 400
 401                 /// <summary>
 402                 ///  This is used to lookup the value of an enum member. If the member is undefined,
 403                 ///  it attempts to define it and return its value
 404                 /// </summary>
 405                 public object LookupEnumValue (EmitContext ec, string name, Location loc)
 406                 {
 407
 408                         object default_value = null;
 409                         Constant c = null;
 410
 411                         default_value = member_to_value [name];
 412
 413                         if (default_value != null)
 414                                 return default_value;
 415
 416                         //
 417                         // This may happen if we're calling a method in System.Enum, for instance
 418                         // Enum.IsDefined().
 419                         //
 420                         if (!defined_names.Contains (name))
 421                                 return null;
 422
 423                         if (in_transit.Contains (name)) {
 424                                 Report.Error (110, loc, "The evaluation of the constant value for `" +
 425                                               Name + "." + name + "' involves a circular definition.");
 426                                 return null;
 427                         }
 428
 429                         //
 430                         // So if the above doesn't happen, we have a member that is undefined
 431                         // We now proceed to define it
 432                         //
 433                         Expression val = this [name];
 434
 435                         if (val == null) {
 436
 437                                 int idx = ordered_enums.IndexOf (name);
 438
 439                                 if (idx == 0)
 440                                         default_value = 0;
 441                                 else {
 442                                         for (int i = 0; i < idx; ++i) {
 443                                                 string n = (string) ordered_enums [i];
 444                                                 Location m_loc = (Mono.CSharp.Location)
 445                                                         member_to_location [n];
 446                                                 in_transit.Add (name, true);
 447
 448                                                 EmitContext old_ec = current_ec;
 449                                                 current_ec = ec;
 450
 451                                                 default_value = LookupEnumValue (ec, n, m_loc);
 452
 453                                                 current_ec = old_ec;
 454
 455                                                 in_transit.Remove (name);
 456                                                 if (default_value == null)
 457                                                         return null;
 458                                         }
 459
 460                                         default_value = GetNextDefaultValue (default_value);
 461                                 }
 462
 463                         } else {
 464                                 bool old = ec.InEnumContext;
 465                                 ec.InEnumContext = true;
 466                                 in_transit.Add (name, true);
 467
 468                                 EmitContext old_ec = current_ec;
 469                                 current_ec = ec;
 470                                 val = val.Resolve (ec);
 471                                 current_ec = old_ec;
 472
 473                                 in_transit.Remove (name);
 474                                 ec.InEnumContext = old;
 475
 476                                 if (val == null)
 477                                         return null;
 478
 479                                 if (!IsValidEnumConstant (val)) {
 480                                         Report.Error (
 481                                                 1008, loc,
 482                                                 "Type byte, sbyte, short, ushort, int, uint, long, or " +
 483                                                 "ulong expected (have: " + val + ")");
 484                                         return null;
 485                                 }
 486
 487                                 c = (Constant) val;
 488                                 default_value = c.GetValue ();
 489
 490                                 if (default_value == null) {
 491                                         Error_ConstantValueCannotBeConverted (c, loc);
 492                                         return null;
 493                                 }
 494
 495                                 if (val is EnumConstant){
 496                                         Type etype = TypeManager.EnumToUnderlying (c.Type);
 497
 498                                         if (!ImplicitConversionExists (etype, UnderlyingType)){
 499                                                 Convert.Error_CannotImplicitConversion (
 500                                                         loc, c.Type, UnderlyingType);
 501                                                 return null;
 502                                         }
 503                                 }
 504                         }
 505
 506                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 507                                         | FieldAttributes.Literal;
 508
 509                         FieldBuilder fb = TypeBuilder.DefineField (name, TypeBuilder, attr);
 510
 511                         bool fail;
 512                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 513                         if (fail){
 514                                 Error_ConstantValueCannotBeConverted (c, loc);
 515                                 return null;
 516                         }
 517
 518                         fb.SetConstant (default_value);
 519                         field_builders.Add (fb);
 520                         member_to_value [name] = default_value;
 521
 522                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 523                                 return null;
 524
 525                         //
 526                         // Now apply attributes
 527                         //
 528                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name]);
 529
 530                         return default_value;
 531                 }
 532
 533                 public override bool DefineMembers (TypeContainer parent)
 534                 {
 535                         return true;
 536                 }
 537
 538                 public override bool Define (TypeContainer parent)
 539                 {
 540                         //
 541                         // If there was an error during DefineEnum, return
 542                         //
 543                         if (TypeBuilder == null)
 544                                 return false;
 545
 546                         EmitContext ec = new EmitContext (this, this, Location, null,
 547                                                           UnderlyingType, ModFlags, false);
 548
 549
 550                         object default_value = 0;
 551
 552                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
 553                                              | FieldAttributes.Literal;
 554
 555
 556                         foreach (string name in ordered_enums) {
 557                                 //
 558                                 // Have we already been defined, thanks to some cross-referencing ?
 559                                 //
 560                                 if (member_to_value.Contains (name))
 561                                         continue;
 562
 563                                 Location loc = (Mono.CSharp.Location) member_to_location [name];
 564
 565                                 if (this [name] != null) {
 566                                         default_value = LookupEnumValue (ec, name, loc);
 567
 568                                         if (default_value == null)
 569                                                 return true;
 570                                 } else {
 571                                         if (name == "value__"){
 572                                                 Report.Error (76, loc, "The name `value__' is reserved for enumerations");
 573                                                 return false;
 574                                         }
 575
 576                                         FieldBuilder fb = TypeBuilder.DefineField (
 577                                                 name, TypeBuilder, attr);
 578
 579                                         if (default_value == null) {
 580                                            Report.Error (543, loc, "Enumerator value for '" + name + "' is too large to " +
 581                                                               "fit in its type");
 582                                                 return false;
 583                                         }
 584
 585                                         bool fail;
 586                                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 587                                         if (fail){
 588                                                 Error_ConstantValueCannotBeConverted (default_value, loc);
 589                                                 return false;
 590                                         }
 591
 592                                         fb.SetConstant (default_value);
 593                                         field_builders.Add (fb);
 594                                         member_to_value [name] = default_value;
 595
 596                                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 597                                                 return false;
 598
 599                                         //
 600                                         // Apply attributes on the enum member
 601                                         //
 602                                         Attribute.ApplyAttributes (ec, fb, fb, (Attributes) member_to_attributes [name]);
 603                                 }
 604
 605                                 default_value = GetNextDefaultValue (default_value);
 606                         }
 607
 608                         Attribute.ApplyAttributes (ec, TypeBuilder, this, OptAttributes);
 609
 610                         return true;
 611                 }
 612
 613                 //
 614                 // IMemberFinder
 615                 //
 616                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 617                                                         MemberFilter filter, object criteria)
 618                 {
 619                         ArrayList members = new ArrayList ();
 620
 621                         if ((mt & MemberTypes.Field) != 0) {
 622                                 if (criteria is string){
 623                                         if (member_to_value [criteria] == null && current_ec != null){
 624                                                 LookupEnumValue (current_ec, (string) criteria, Location.Null);
 625                                         }
 626                                 }
 627
 628                                 foreach (FieldBuilder fb in field_builders)
 629                                         if (filter (fb, criteria) == true)
 630                                                 members.Add (fb);
 631                         }
 632
 633                         return new MemberList (members);
 634                 }
 635
 636                 public override MemberCache MemberCache {
 637                         get {
 638                                 return null;
 639                         }
 640                 }
 641
 642                 public ArrayList ValueNames {
 643                         get {
 644                                 return ordered_enums;
 645                         }
 646                 }
 647
 648                 // indexer
 649                 public Expression this [string name] {
 650                         get {
 651                                 return (Expression) defined_names [name];
 652                         }
 653                 }
 654         }
 655 }