mcs/mcs/anonymous.cs

   1 //
   2 // anonymous.cs: Support for anonymous methods and types
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximain.com)
   6 //   Marek Safar (marek.safar@gmail.com)
   7 //
   8 // Dual licensed under the terms of the MIT X11 or GNU GPL
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11
  12 using System;
  13 using System.Text;
  14 using System.Collections;
  15 using System.Collections.Specialized;
  16 using System.Reflection;
  17 using System.Reflection.Emit;
  18
  19 namespace Mono.CSharp {
  20
  21         public abstract class CompilerGeneratedClass : Class
  22         {
  23                 public static string MakeName (string host, string typePrefix, string name, int id)
  24                 {
  25                         return "<" + host + ">" + typePrefix + "__" + name + id.ToString ("X");
  26                 }
  27
  28                 protected CompilerGeneratedClass (DeclSpace parent, MemberName name, int mod)
  29                         : base (parent.NamespaceEntry, parent, name, mod | Modifiers.COMPILER_GENERATED | Modifiers.SEALED, null)
  30                 {
  31                 }
  32
  33                 protected CompilerGeneratedClass (DeclSpace parent, GenericMethod generic, MemberName name, int mod)
  34                         : this (parent, name, mod)
  35                 {
  36                         if (generic != null) {
  37                                 ArrayList list = new ArrayList ();
  38                                 foreach (TypeParameter tparam in generic.TypeParameters) {
  39                                         if (tparam.Constraints != null)
  40                                                 list.Add (tparam.Constraints.Clone ());
  41                                 }
  42                                 SetParameterInfo (list);
  43                         }
  44                 }
  45
  46                 protected void CheckMembersDefined ()
  47                 {
  48                         if (members_defined)
  49                                 throw new InternalErrorException ("Helper class already defined!");
  50                 }
  51         }
  52
  53         //
  54         // Anonymous method storey is created when an anonymous method uses
  55         // variable or parameter from outer scope. They are then hoisted to
  56         // anonymous method storey (captured)
  57         //
  58         public class AnonymousMethodStorey : CompilerGeneratedClass
  59         {
  60                 class StoreyFieldPair {
  61                         public readonly AnonymousMethodStorey Storey;
  62                         public readonly Field Field;
  63
  64                         public StoreyFieldPair (AnonymousMethodStorey storey, Field field)
  65                         {
  66                                 this.Storey = storey;
  67                                 this.Field = field;
  68                         }
  69
  70                         public override int GetHashCode ()
  71                         {
  72                                 return Storey.ID.GetHashCode ();
  73                         }
  74
  75                         public override bool Equals (object obj)
  76                         {
  77                                 return (AnonymousMethodStorey)obj == Storey;
  78                         }
  79                 }
  80
  81                 sealed class HoistedGenericField : Field
  82                 {
  83                         public HoistedGenericField (DeclSpace parent, FullNamedExpression type, int mod, string name,
  84                                   Attributes attrs, Location loc)
  85                                 : base (parent, type, mod, new MemberName (name, loc), attrs)
  86                         {
  87                         }
  88
  89                         protected override bool ResolveMemberType ()
  90                         {
  91                                 if (!base.ResolveMemberType ())
  92                                         return false;
  93
  94                                 AnonymousMethodStorey parent = ((AnonymousMethodStorey) Parent).GetGenericStorey ();
  95                                 if (parent != null)
  96                                         member_type = parent.MutateType (member_type);
  97
  98                                 return true;
  99                         }
 100                 }
 101
 102                 //
 103                 // Needed to delay hoisted _this_ initialization. When an anonymous
 104                 // method is used inside ctor and _this_ is hoisted, base ctor has to
 105                 // be called first, otherwise _this_ will be initialized with
 106                 // uninitialized value.
 107                 //
 108                 public sealed class ThisInitializer : Statement
 109                 {
 110                         readonly AnonymousMethodStorey storey;
 111
 112                         public ThisInitializer (AnonymousMethodStorey storey)
 113                         {
 114                                 this.storey = storey;
 115                         }
 116
 117                         protected override void DoEmit (EmitContext ec)
 118                         {
 119                                 if (storey.hoisted_this != null) {
 120                                         storey.hoisted_this.EmitHoistingAssignment (ec);
 121                                 }
 122                         }
 123
 124                         protected override void CloneTo (CloneContext clonectx, Statement target)
 125                         {
 126                                 // Nothing to clone
 127                         }
 128
 129                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
 130                         {
 131                                 // Nothing to mutate
 132                         }
 133                 }
 134
 135                 // Unique storey ID
 136                 public readonly int ID;
 137                 static int unique_id;
 138
 139                 public readonly Block OriginalSourceBlock;
 140
 141                 // A list of StoreyFieldPair with local field keeping parent storey instance
 142                 ArrayList used_parent_storeys;
 143                 ArrayList children_references;
 144
 145                 // A list of hoisted parameters
 146                 protected ArrayList hoisted_params;
 147                 protected ArrayList hoisted_locals;
 148
 149                 // Hoisted this
 150                 protected HoistedThis hoisted_this;
 151
 152                 // Local variable which holds this storey instance
 153                 public LocalTemporary Instance;
 154
 155                 public AnonymousMethodStorey (Block block, DeclSpace parent, MemberBase host, GenericMethod generic, string name)
 156                         : base (parent, generic, MakeMemberName (host, name, generic, block.StartLocation), Modifiers.PRIVATE)
 157                 {
 158                         Parent = parent;
 159                         OriginalSourceBlock = block;
 160                         ID = unique_id++;
 161                 }
 162
 163                 static MemberName MakeMemberName (MemberBase host, string name, GenericMethod generic, Location loc)
 164                 {
 165                         string host_name = host == null ? null : host.Name;
 166                         string tname = MakeName (host_name, "c", name, unique_id);
 167                         TypeArguments args = null;
 168                         if (generic != null) {
 169                                 args = new TypeArguments ();
 170                                 foreach (TypeParameter tparam in generic.CurrentTypeParameters)
 171                                         args.Add (new TypeParameterName (tparam.Name, null, loc));
 172                         }
 173
 174                         return new MemberName (tname, args, loc);
 175                 }
 176
 177                 public void AddCapturedThisField (EmitContext ec)
 178                 {
 179                         TypeExpr type_expr = new TypeExpression (ec.ContainerType, Location);
 180                         Field f = AddCompilerGeneratedField ("<>f__this", type_expr);
 181                         f.Define ();
 182                         hoisted_this = new HoistedThis (this, f);
 183                 }
 184
 185                 public Field AddCapturedVariable (string name, Type type)
 186                 {
 187                         CheckMembersDefined ();
 188
 189                         FullNamedExpression field_type = new TypeExpression (type, Location);
 190                         if (!IsGeneric)
 191                                 return AddCompilerGeneratedField (name, field_type);
 192
 193                         const int mod = Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED;
 194                         Field f = new HoistedGenericField (this, field_type, mod, name, null, Location);
 195                         AddField (f);
 196                         return f;
 197                 }
 198
 199                 protected Field AddCompilerGeneratedField (string name, FullNamedExpression type)
 200                 {
 201                         const int mod = Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED;
 202                         Field f = new Field (this, type, mod, new MemberName (name, Location), null);
 203                         AddField (f);
 204                         return f;
 205                 }
 206
 207                 //
 208                 // Creates a link between block and the anonymous method storey
 209                 //
 210                 // An anonymous method can reference variables from any outer block, but they are
 211                 // hoisted in their own ExplicitBlock. When more than one block is referenced we
 212                 // need to create another link between those variable storeys
 213                 //
 214                 public void AddReferenceFromChildrenBlock (ExplicitBlock block)
 215                 {
 216                         if (children_references == null)
 217                                 children_references = new ArrayList ();
 218
 219                         if (!children_references.Contains (block))
 220                                 children_references.Add (block);
 221                 }
 222
 223                 public void AddParentStoreyReference (AnonymousMethodStorey storey)
 224                 {
 225                         CheckMembersDefined ();
 226
 227                         if (used_parent_storeys == null)
 228                                 used_parent_storeys = new ArrayList ();
 229                         else if (used_parent_storeys.IndexOf (storey) != -1)
 230                                 return;
 231
 232                         TypeExpr type_expr = new TypeExpression (storey.TypeBuilder, Location);
 233                         Field f = AddCompilerGeneratedField ("<>f__ref$" + storey.ID, type_expr);
 234                         used_parent_storeys.Add (new StoreyFieldPair (storey, f));
 235                 }
 236
 237                 public void CaptureLocalVariable (EmitContext ec, LocalInfo local_info)
 238                 {
 239                         ec.CurrentBlock.Explicit.HasCapturedVariable = true;
 240                         if (ec.CurrentBlock.Explicit != local_info.Block.Explicit)
 241                                 AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
 242
 243                         if (local_info.HoistedVariableReference != null)
 244                                 return;
 245
 246                         HoistedVariable var = new HoistedLocalVariable (this, local_info, GetVariableMangledName (local_info));
 247                         local_info.HoistedVariableReference = var;
 248
 249                         if (hoisted_locals == null)
 250                                 hoisted_locals = new ArrayList ();
 251
 252                         hoisted_locals.Add (var);
 253                 }
 254
 255                 public void CaptureParameter (EmitContext ec, ParameterReference param_ref)
 256                 {
 257                         ec.CurrentBlock.Explicit.HasCapturedVariable = true;
 258                         AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
 259
 260                         if (param_ref.GetHoistedVariable (ec) != null)
 261                                 return;
 262
 263                         if (hoisted_params == null)
 264                                 hoisted_params = new ArrayList (2);
 265
 266                         HoistedVariable expr = new HoistedParameter (this, param_ref);
 267                         param_ref.Parameter.HoistedVariableReference = expr;
 268                         hoisted_params.Add (expr);
 269                 }
 270
 271                 public void ChangeParentStorey (AnonymousMethodStorey parentStorey)
 272                 {
 273                         Parent = parentStorey;
 274                         type_params = null;
 275                 }
 276
 277                 //
 278                 // Initializes all hoisted variables
 279                 //
 280                 public void EmitStoreyInstantiation (EmitContext ec)
 281                 {
 282                         // There can be only one instance variable for each storey type
 283                         if (Instance != null)
 284                                 throw new InternalErrorException ();
 285
 286                         SymbolWriter.OpenCompilerGeneratedBlock (ec.ig);
 287
 288                         //
 289                         // Create an instance of storey type
 290                         //
 291                         Expression storey_type_expr;
 292                         if (is_generic) {
 293                                 //
 294                                 // Use current method type parameter (MVAR) for top level storey only. All
 295                                 // nested storeys use class type parameter (VAR)
 296                                 //
 297                                 TypeParameter[] tparams = ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.Storey != null ?
 298                                         ec.CurrentAnonymousMethod.Storey.TypeParameters :
 299                                         ec.GenericDeclContainer.TypeParameters;
 300
 301                                 TypeArguments targs = new TypeArguments ();
 302
 303                                 if (tparams.Length < CountTypeParameters) {
 304                                         TypeParameter[] parent_tparams = ec.DeclContainer.Parent.PartialContainer.TypeParameters;
 305                                         for (int i = 0; i < parent_tparams.Length; ++i)
 306                                                 targs.Add (new TypeParameterExpr (parent_tparams[i], Location));
 307                                 }
 308
 309                                 for (int i = 0; i < tparams.Length; ++i)
 310                                         targs.Add (new TypeParameterExpr (tparams[i], Location));
 311
 312                                 storey_type_expr = new GenericTypeExpr (TypeBuilder, targs, Location);
 313                         } else {
 314                                 storey_type_expr = new TypeExpression (TypeBuilder, Location);
 315                         }
 316
 317                         Expression e = new New (storey_type_expr, new ArrayList (0), Location).Resolve (ec);
 318                         e.Emit (ec);
 319
 320                         Instance = new LocalTemporary (storey_type_expr.Type);
 321                         Instance.Store (ec);
 322
 323                         EmitHoistedFieldsInitialization (ec);
 324
 325                         SymbolWriter.DefineScopeVariable (ID, Instance.Builder);
 326                         SymbolWriter.CloseCompilerGeneratedBlock (ec.ig);
 327                 }
 328
 329                 void EmitHoistedFieldsInitialization (EmitContext ec)
 330                 {
 331                         //
 332                         // Initialize all storey reference fields by using local or hoisted variables
 333                         //
 334                         if (used_parent_storeys != null) {
 335                                 foreach (StoreyFieldPair sf in used_parent_storeys) {
 336                                         //
 337                                         // Setting local field
 338                                         //
 339                                         Expression instace_expr = GetStoreyInstanceExpression (ec);
 340                                         FieldExpr f_set_expr = TypeManager.IsGenericType (instace_expr.Type) ?
 341                                                 new FieldExpr (sf.Field.FieldBuilder, instace_expr.Type, Location) :
 342                                                 new FieldExpr (sf.Field.FieldBuilder, Location);
 343                                         f_set_expr.InstanceExpression = instace_expr;
 344
 345                                         SimpleAssign a = new SimpleAssign (f_set_expr, sf.Storey.GetStoreyInstanceExpression (ec));
 346                                         if (a.Resolve (ec) != null)
 347                                                 a.EmitStatement (ec);
 348                                 }
 349                         }
 350
 351                         //
 352                         // Define hoisted `this' in top-level storey only
 353                         //
 354                         if (OriginalSourceBlock.Explicit.HasCapturedThis && !(Parent is AnonymousMethodStorey)) {
 355                                 AddCapturedThisField (ec);
 356                                 hoisted_this.EmitHoistingAssignment (ec);
 357                         }
 358
 359                         //
 360                         // Setting currect anonymous method to null blocks any further variable hoisting
 361                         //
 362                         AnonymousExpression ae = ec.CurrentAnonymousMethod;
 363                         ec.CurrentAnonymousMethod = null;
 364
 365                         if (hoisted_params != null) {
 366                                 EmitHoistedParameters (ec, hoisted_params);
 367                         }
 368
 369                         ec.CurrentAnonymousMethod = ae;
 370                 }
 371
 372                 protected virtual void EmitHoistedParameters (EmitContext ec, ArrayList hoisted)
 373                 {
 374                         foreach (HoistedParameter hp in hoisted) {
 375                                 hp.EmitHoistingAssignment (ec);
 376                         }
 377                 }
 378
 379                 public override void EmitType ()
 380                 {
 381                         SymbolWriter.DefineAnonymousScope (ID);
 382
 383                         if (hoisted_this != null)
 384                                 hoisted_this.EmitSymbolInfo ();
 385
 386                         if (hoisted_locals != null) {
 387                                 foreach (HoistedVariable local in hoisted_locals)
 388                                         local.EmitSymbolInfo ();
 389                         }
 390
 391                         if (hoisted_params != null) {
 392                                 foreach (HoistedParameter param in hoisted_params)
 393                                         param.EmitSymbolInfo ();
 394                         }
 395
 396                         if (used_parent_storeys != null) {
 397                                 foreach (StoreyFieldPair sf in used_parent_storeys) {
 398                                         SymbolWriter.DefineCapturedScope (ID, sf.Storey.ID, sf.Field.Name);
 399                                 }
 400                         }
 401
 402                         base.EmitType ();
 403                 }
 404
 405                 public AnonymousMethodStorey GetGenericStorey ()
 406                 {
 407                         DeclSpace storey = this;
 408                         while (storey != null && storey.CurrentTypeParameters.Length == 0)
 409                                 storey = storey.Parent;
 410
 411                         return storey as AnonymousMethodStorey;
 412                 }
 413
 414                 //
 415                 // Returns a field which holds referenced storey instance
 416                 //
 417                 Field GetReferencedStoreyField (AnonymousMethodStorey storey)
 418                 {
 419                         if (used_parent_storeys == null)
 420                                 return null;
 421
 422                         foreach (StoreyFieldPair sf in used_parent_storeys) {
 423                                 if (sf.Storey == storey)
 424                                         return sf.Field;
 425                         }
 426
 427                         return null;
 428                 }
 429
 430                 //
 431                 // Creates storey instance expression regardless of currect IP
 432                 //
 433                 public Expression GetStoreyInstanceExpression (EmitContext ec)
 434                 {
 435                         AnonymousExpression am = ec.CurrentAnonymousMethod;
 436
 437                         //
 438                         // Access from original block -> storey
 439                         //
 440                         if (am == null)
 441                                 return Instance;
 442
 443                         //
 444                         // Access from anonymous method implemented as a static -> storey
 445                         //
 446                         if (am.Storey == null)
 447                                 return Instance;
 448
 449                         Field f = am.Storey.GetReferencedStoreyField (this);
 450                         if (f == null) {
 451                                 if (am.Storey == this) {
 452                                         //
 453                                         // Access inside of same storey (S -> S)
 454                                         //
 455                                         return new CompilerGeneratedThis (TypeBuilder, Location);
 456                                 }
 457                                 //
 458                                 // External field access
 459                                 //
 460                                 return Instance;
 461                         }
 462
 463                         //
 464                         // Storey was cached to local field
 465                         //
 466                         FieldExpr f_ind = new FieldExpr (f.FieldBuilder, Location);
 467                         f_ind.InstanceExpression = new CompilerGeneratedThis (TypeBuilder, Location);
 468                         return f_ind;
 469                 }
 470
 471                 protected virtual string GetVariableMangledName (LocalInfo local_info)
 472                 {
 473                         //
 474                         // No need to mangle anonymous method hoisted variables cause they
 475                         // are hoisted in their own scopes
 476                         //
 477                         return local_info.Name;
 478                 }
 479
 480                 public HoistedThis HoistedThis {
 481                         get { return hoisted_this; }
 482                 }
 483
 484                 //
 485                 // Mutate type dispatcher
 486                 //
 487                 public Type MutateType (Type type)
 488                 {
 489 #if GMCS_SOURCE
 490                         if (TypeManager.IsGenericType (type))
 491                                 return MutateGenericType (type);
 492
 493                         if (TypeManager.IsGenericParameter (type))
 494                                 return MutateGenericArgument (type);
 495
 496                         if (type.IsArray)
 497                                 return MutateArrayType (type);
 498 #endif
 499                         return type;
 500                 }
 501
 502                 //
 503                 // Changes method type arguments (MVAR) to storey (VAR) type arguments
 504                 //
 505                 public MethodInfo MutateGenericMethod (MethodInfo method)
 506                 {
 507 #if GMCS_SOURCE
 508                         Type [] t_args = TypeManager.GetGenericArguments (method);
 509                         if (TypeManager.IsGenericType (method.DeclaringType)) {
 510                                 Type t = MutateGenericType (method.DeclaringType);
 511                                 if (t != method.DeclaringType) {
 512                                         method = (MethodInfo) TypeManager.DropGenericMethodArguments (method);
 513                                         if (method.Module == CodeGen.Module.Builder)
 514                                                 method = TypeBuilder.GetMethod (t, method);
 515                                         else
 516                                                 method = (MethodInfo) MethodInfo.GetMethodFromHandle (method.MethodHandle, t.TypeHandle);
 517                                 }
 518                         }
 519
 520                         if (t_args == null || t_args.Length == 0)
 521                                 return method;
 522
 523                         for (int i = 0; i < t_args.Length; ++i)
 524                                 t_args [i] = MutateType (t_args [i]);
 525
 526                         return method.GetGenericMethodDefinition ().MakeGenericMethod (t_args);
 527 #else
 528                         throw new NotSupportedException ();
 529 #endif
 530                 }
 531
 532                 public ConstructorInfo MutateConstructor (ConstructorInfo ctor)
 533                 {
 534 #if GMCS_SOURCE
 535                         if (TypeManager.IsGenericType (ctor.DeclaringType)) {
 536                                 Type t = MutateGenericType (ctor.DeclaringType);
 537                                 if (t != ctor.DeclaringType) {
 538                                         ctor = (ConstructorInfo) TypeManager.DropGenericMethodArguments (ctor);
 539                                         if (ctor.Module == CodeGen.Module.Builder)
 540                                                 return TypeBuilder.GetConstructor (t, ctor);
 541
 542                                         return (ConstructorInfo) ConstructorInfo.GetMethodFromHandle (ctor.MethodHandle, t.TypeHandle);
 543                                 }
 544                         }
 545 #endif
 546                         return ctor;
 547                 }
 548
 549                 public FieldInfo MutateField (FieldInfo field)
 550                 {
 551 #if GMCS_SOURCE
 552                         if (TypeManager.IsGenericType (field.DeclaringType)) {
 553                                 Type t = MutateGenericType (field.DeclaringType);
 554                                 if (t != field.DeclaringType) {
 555                                         // TODO: It should throw on imported types
 556                                         return TypeBuilder.GetField (t, field);
 557                                 }
 558                         }
 559 #endif
 560                         return field;
 561                 }
 562
 563 #if GMCS_SOURCE
 564                 protected Type MutateArrayType (Type array)
 565                 {
 566                         int rank = array.GetArrayRank ();
 567                         Type element = TypeManager.GetElementType (array);
 568                         if (element.IsArray)
 569                                 throw new NotImplementedException ();
 570
 571                         if (TypeManager.IsGenericParameter (element)) {
 572                                 element = MutateGenericArgument (element);
 573                         } else if (TypeManager.IsGenericType (element)) {
 574                                 element = MutateGenericType (element);
 575                         } else {
 576                                 return array;
 577                         }
 578
 579                         return element.MakeArrayType (rank);
 580                 }
 581
 582                 protected Type MutateGenericType (Type type)
 583                 {
 584                         Type [] t_args = TypeManager.GetTypeArguments (type);
 585                         if (t_args == null || t_args.Length == 0)
 586                                 return type;
 587
 588                         for (int i = 0; i < t_args.Length; ++i)
 589                                 t_args [i] = MutateType (t_args [i]);
 590
 591                         return type.GetGenericTypeDefinition ().MakeGenericType (t_args);
 592                 }
 593 #endif
 594
 595                 //
 596                 // Changes method generic argument (MVAR) to type generic argument (VAR)
 597                 //
 598                 public Type MutateGenericArgument (Type type)
 599                 {
 600                         foreach (TypeParameter tp in CurrentTypeParameters) {
 601                                 if (tp.Name == type.Name) {
 602                                         return tp.Type;
 603                                 }
 604                         }
 605
 606                         return type;
 607                 }
 608
 609                 public ArrayList ReferencesFromChildrenBlock {
 610                         get { return children_references; }
 611                 }
 612
 613                 public static void Reset ()
 614                 {
 615                         unique_id = 0;
 616                 }
 617         }
 618
 619         public abstract class HoistedVariable
 620         {
 621                 class ExpressionTreeProxy : Expression
 622                 {
 623                         readonly HoistedVariable hv;
 624
 625                         public ExpressionTreeProxy (HoistedVariable hv)
 626                         {
 627                                 this.hv = hv;
 628                         }
 629
 630                         public override Expression CreateExpressionTree (EmitContext ec)
 631                         {
 632                                 throw new NotSupportedException ("ET");
 633                         }
 634
 635                         public override Expression DoResolve (EmitContext ec)
 636                         {
 637                                 eclass = ExprClass.Value;
 638                                 type = TypeManager.expression_type_expr.Type;
 639                                 return this;
 640                         }
 641
 642                         public override void Emit (EmitContext ec)
 643                         {
 644                                 Expression e = hv.GetFieldExpression (ec).CreateExpressionTree (ec);
 645                                 // This should never fail
 646                                 e = e.Resolve (ec);
 647                                 if (e != null)
 648                                         e.Emit (ec);
 649                         }
 650                 }
 651
 652                 protected readonly AnonymousMethodStorey storey;
 653                 protected Field field;
 654                 Hashtable cached_inner_access; // TODO: Hashtable is too heavyweight
 655                 FieldExpr cached_outer_access;
 656
 657                 protected HoistedVariable (AnonymousMethodStorey storey, string name, Type type)
 658                         : this (storey, storey.AddCapturedVariable (name, type))
 659                 {
 660                 }
 661
 662                 protected HoistedVariable (AnonymousMethodStorey storey, Field field)
 663                 {
 664                         this.storey = storey;
 665                         this.field = field;
 666                 }
 667
 668                 public void AddressOf (EmitContext ec, AddressOp mode)
 669                 {
 670                         GetFieldExpression (ec).AddressOf (ec, mode);
 671                 }
 672
 673                 public Expression CreateExpressionTree (EmitContext ec)
 674                 {
 675                         return new ExpressionTreeProxy (this);
 676                 }
 677
 678                 public void Emit (EmitContext ec)
 679                 {
 680                         GetFieldExpression (ec).Emit (ec);
 681                 }
 682
 683                 //
 684                 // Creates field access expression for hoisted variable
 685                 //
 686                 protected FieldExpr GetFieldExpression (EmitContext ec)
 687                 {
 688                         if (ec.CurrentAnonymousMethod == null || ec.CurrentAnonymousMethod.Storey == null) {
 689                                 if (cached_outer_access != null)
 690                                         return cached_outer_access;
 691
 692                                 //
 693                                 // When setting top-level hoisted variable in generic storey
 694                                 // change storey generic types to method generic types (VAR -> MVAR)
 695                                 //
 696                                 cached_outer_access = storey.MemberName.IsGeneric ?
 697                                         new FieldExpr (field.FieldBuilder, storey.Instance.Type, field.Location) :
 698                                         new FieldExpr (field.FieldBuilder, field.Location);
 699
 700                                 cached_outer_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
 701                                 cached_outer_access.Resolve (ec);
 702                                 return cached_outer_access;
 703                         }
 704
 705                         FieldExpr inner_access;
 706                         if (cached_inner_access != null) {
 707                                 inner_access = (FieldExpr) cached_inner_access [ec.CurrentAnonymousMethod];
 708                         } else {
 709                                 inner_access = null;
 710                                 cached_inner_access = new Hashtable (4);
 711                         }
 712
 713                         if (inner_access == null) {
 714                                 inner_access = new FieldExpr (field.FieldBuilder, field.Location);
 715                                 inner_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
 716                                 inner_access.Resolve (ec);
 717                                 cached_inner_access.Add (ec.CurrentAnonymousMethod, inner_access);
 718                         }
 719
 720                         return inner_access;
 721                 }
 722
 723                 public abstract void EmitSymbolInfo ();
 724
 725                 public void Emit (EmitContext ec, bool leave_copy)
 726                 {
 727                         GetFieldExpression (ec).Emit (ec, leave_copy);
 728                 }
 729
 730                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
 731                 {
 732                         GetFieldExpression (ec).EmitAssign (ec, source, leave_copy, false);
 733                 }
 734         }
 735
 736         class HoistedParameter : HoistedVariable
 737         {
 738                 sealed class HoistedFieldAssign : Assign
 739                 {
 740                         public HoistedFieldAssign (Expression target, Expression source)
 741                                 : base (target, source, source.Location)
 742                         {
 743                         }
 744
 745                         protected override Expression ResolveConversions (EmitContext ec)
 746                         {
 747                                 //
 748                                 // Implicit conversion check fails for hoisted type arguments
 749                                 // as they are of different types (!!0 x !0)
 750                                 //
 751                                 return this;
 752                         }
 753                 }
 754
 755                 readonly ParameterReference parameter;
 756
 757                 public HoistedParameter (AnonymousMethodStorey scope, ParameterReference par)
 758                         : base (scope, par.Name, par.Type)
 759                 {
 760                         this.parameter = par;
 761                 }
 762
 763                 public HoistedParameter (HoistedParameter hp, string name)
 764                         : base (hp.storey, name, hp.parameter.Type)
 765                 {
 766                         this.parameter = hp.parameter;
 767                 }
 768
 769                 public void EmitHoistingAssignment (EmitContext ec)
 770                 {
 771                         //
 772                         // Remove hoisted redirection to emit assignment from original parameter
 773                         //
 774                         HoistedVariable temp = parameter.Parameter.HoistedVariableReference;
 775                         parameter.Parameter.HoistedVariableReference = null;
 776
 777                         Assign a = new HoistedFieldAssign (GetFieldExpression (ec), parameter);
 778                         if (a.Resolve (ec) != null)
 779                                 a.EmitStatement (ec);
 780
 781                         parameter.Parameter.HoistedVariableReference = temp;
 782                 }
 783
 784                 public override void EmitSymbolInfo ()
 785                 {
 786                         SymbolWriter.DefineCapturedParameter (storey.ID, field.Name, field.Name);
 787                 }
 788
 789                 public Field Field {
 790                         get { return field; }
 791                 }
 792         }
 793
 794         class HoistedLocalVariable : HoistedVariable
 795         {
 796                 readonly string name;
 797
 798                 public HoistedLocalVariable (AnonymousMethodStorey scope, LocalInfo local, string name)
 799                         : base (scope, name, local.VariableType)
 800                 {
 801                         this.name = local.Name;
 802                 }
 803
 804                 public override void EmitSymbolInfo ()
 805                 {
 806                         SymbolWriter.DefineCapturedLocal (storey.ID, name, field.Name);
 807                 }
 808         }
 809
 810         public class HoistedThis : HoistedVariable
 811         {
 812                 public HoistedThis (AnonymousMethodStorey storey, Field field)
 813                         : base (storey, field)
 814                 {
 815                 }
 816
 817                 public void EmitHoistingAssignment (EmitContext ec)
 818                 {
 819                         SimpleAssign a = new SimpleAssign (GetFieldExpression (ec), ec.GetThis (field.Location));
 820                         if (a.Resolve (ec) != null)
 821                                 a.EmitStatement (ec);
 822                 }
 823
 824                 public override void EmitSymbolInfo ()
 825                 {
 826                         SymbolWriter.DefineCapturedThis (storey.ID, field.Name);
 827                 }
 828
 829                 public Field Field {
 830                         get { return field; }
 831                 }
 832         }
 833
 834         //
 835         // Anonymous method expression as created by parser
 836         //
 837         public class AnonymousMethodExpression : Expression
 838         {
 839                 ListDictionary compatibles;
 840                 public ToplevelBlock Block;
 841
 842                 public AnonymousMethodExpression (Location loc)
 843                 {
 844                         this.loc = loc;
 845                         this.compatibles = new ListDictionary ();
 846                 }
 847
 848                 public override string ExprClassName {
 849                         get {
 850                                 return "anonymous method";
 851                         }
 852                 }
 853
 854                 public virtual bool HasExplicitParameters {
 855                         get {
 856                                 return Parameters != Parameters.Undefined;
 857                         }
 858                 }
 859
 860                 public Parameters Parameters {
 861                         get { return Block.Parameters; }
 862                 }
 863
 864                 //
 865                 // Returns true if the body of lambda expression can be implicitly
 866                 // converted to the delegate of type `delegate_type'
 867                 //
 868                 public bool ImplicitStandardConversionExists (EmitContext ec, Type delegate_type)
 869                 {
 870                         using (ec.Set (EmitContext.Flags.ProbingMode)) {
 871                                 return Compatible (ec, delegate_type) != null;
 872                         }
 873                 }
 874
 875                 protected Type CompatibleChecks (EmitContext ec, Type delegate_type)
 876                 {
 877                         if (TypeManager.IsDelegateType (delegate_type))
 878                                 return delegate_type;
 879
 880 #if GMCS_SOURCE
 881                         if (TypeManager.DropGenericTypeArguments (delegate_type) == TypeManager.expression_type) {
 882                                 delegate_type = TypeManager.GetTypeArguments (delegate_type) [0];
 883                                 if (TypeManager.IsDelegateType (delegate_type))
 884                                         return delegate_type;
 885
 886                                 Report.Error (835, loc, "Cannot convert `{0}' to an expression tree of non-delegate type `{1}'",
 887                                         GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 888                                 return null;
 889                         }
 890 #endif
 891
 892                         Report.Error (1660, loc, "Cannot convert `{0}' to non-delegate type `{1}'",
 893                                       GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 894                         return null;
 895                 }
 896
 897                 protected bool VerifyExplicitParameters (Type delegate_type, AParametersCollection parameters, bool ignore_error)
 898                 {
 899                         if (VerifyParameterCompatibility (delegate_type, parameters, ignore_error))
 900                                 return true;
 901
 902                         if (!ignore_error)
 903                                 Report.Error (1661, loc,
 904                                         "Cannot convert `{0}' to delegate type `{1}' since there is a parameter mismatch",
 905                                         GetSignatureForError (), TypeManager.CSharpName (delegate_type));
 906
 907                         return false;
 908                 }
 909
 910                 protected bool VerifyParameterCompatibility (Type delegate_type, AParametersCollection invoke_pd, bool ignore_errors)
 911                 {
 912                         if (Parameters.Count != invoke_pd.Count) {
 913                                 if (ignore_errors)
 914                                         return false;
 915
 916                                 Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 917                                               TypeManager.CSharpName (delegate_type), Parameters.Count.ToString ());
 918                                 return false;
 919                         }
 920
 921                         bool has_implicit_parameters = !HasExplicitParameters;
 922                         bool error = false;
 923
 924                         for (int i = 0; i < Parameters.Count; ++i) {
 925                                 Parameter.Modifier p_mod = invoke_pd.FixedParameters [i].ModFlags;
 926                                 if (Parameters.FixedParameters [i].ModFlags != p_mod && p_mod != Parameter.Modifier.PARAMS) {
 927                                         if (ignore_errors)
 928                                                 return false;
 929
 930                                         if (p_mod == Parameter.Modifier.NONE)
 931                                                 Report.Error (1677, loc, "Parameter `{0}' should not be declared with the `{1}' keyword",
 932                                                               (i + 1).ToString (), Parameter.GetModifierSignature (Parameters.FixedParameters [i].ModFlags));
 933                                         else
 934                                                 Report.Error (1676, loc, "Parameter `{0}' must be declared with the `{1}' keyword",
 935                                                               (i+1).ToString (), Parameter.GetModifierSignature (p_mod));
 936                                         error = true;
 937                                 }
 938
 939                                 if (has_implicit_parameters)
 940                                         continue;
 941
 942                                 Type type = invoke_pd.Types [i];
 943
 944                                 // We assume that generic parameters are always inflated
 945                                 if (TypeManager.IsGenericParameter (type))
 946                                         continue;
 947
 948                                 if (TypeManager.HasElementType (type) && TypeManager.IsGenericParameter (TypeManager.GetElementType (type)))
 949                                         continue;
 950
 951                                 if (invoke_pd.Types [i] != Parameters.Types [i]) {
 952                                         if (ignore_errors)
 953                                                 return false;
 954
 955                                         Report.Error (1678, loc, "Parameter `{0}' is declared as type `{1}' but should be `{2}'",
 956                                                       (i+1).ToString (),
 957                                                       TypeManager.CSharpName (Parameters.Types [i]),
 958                                                       TypeManager.CSharpName (invoke_pd.Types [i]));
 959                                         error = true;
 960                                 }
 961                         }
 962
 963                         return !error;
 964                 }
 965
 966                 //
 967                 // Infers type arguments based on explicit arguments
 968                 //
 969                 public bool ExplicitTypeInference (TypeInferenceContext type_inference, Type delegate_type)
 970                 {
 971                         if (!HasExplicitParameters)
 972                                 return false;
 973
 974                         if (!TypeManager.IsDelegateType (delegate_type)) {
 975 #if GMCS_SOURCE
 976                                 if (TypeManager.DropGenericTypeArguments (delegate_type) != TypeManager.expression_type)
 977                                         return false;
 978
 979                                 delegate_type = delegate_type.GetGenericArguments () [0];
 980                                 if (!TypeManager.IsDelegateType (delegate_type))
 981                                         return false;
 982 #else
 983                                 return false;
 984 #endif
 985                         }
 986
 987                         AParametersCollection d_params = TypeManager.GetDelegateParameters (delegate_type);
 988                         if (d_params.Count != Parameters.Count)
 989                                 return false;
 990
 991                         for (int i = 0; i < Parameters.Count; ++i) {
 992                                 Type itype = d_params.Types [i];
 993                                 if (!TypeManager.IsGenericParameter (itype)) {
 994                                         if (!TypeManager.HasElementType (itype))
 995                                                 continue;
 996
 997                                         if (!TypeManager.IsGenericParameter (TypeManager.GetElementType (itype)))
 998                                             continue;
 999                                 }
1000                                 type_inference.ExactInference (Parameters.Types [i], itype);
1001                         }
1002                         return true;
1003                 }
1004
1005                 public Type InferReturnType (EmitContext ec, TypeInferenceContext tic, Type delegate_type)
1006                 {
1007                         AnonymousMethodBody am;
1008                         using (ec.Set (EmitContext.Flags.ProbingMode | EmitContext.Flags.InferReturnType)) {
1009                                 am = CompatibleMethod (ec, tic, GetType (), delegate_type);
1010                         }
1011
1012                         if (am == null)
1013                                 return null;
1014
1015                         if (am.ReturnType == TypeManager.null_type)
1016                                 am.ReturnType = null;
1017
1018                         return am.ReturnType;
1019                 }
1020
1021                 //
1022                 // Returns AnonymousMethod container if this anonymous method
1023                 // expression can be implicitly converted to the delegate type `delegate_type'
1024                 //
1025                 public Expression Compatible (EmitContext ec, Type type)
1026                 {
1027                         Expression am = (Expression) compatibles [type];
1028                         if (am != null)
1029                                 return am;
1030
1031                         Type delegate_type = CompatibleChecks (ec, type);
1032                         if (delegate_type == null)
1033                                 return null;
1034
1035                         //
1036                         // At this point its the first time we know the return type that is
1037                         // needed for the anonymous method.  We create the method here.
1038                         //
1039
1040                         MethodInfo invoke_mb = Delegate.GetInvokeMethod (
1041                                 ec.ContainerType, delegate_type);
1042                         Type return_type = TypeManager.TypeToCoreType (invoke_mb.ReturnType);
1043
1044 #if MS_COMPATIBLE
1045                         Type[] g_args = delegate_type.GetGenericArguments ();
1046                         if (return_type.IsGenericParameter)
1047                                 return_type = g_args [return_type.GenericParameterPosition];
1048 #endif
1049
1050                         //
1051                         // Second: the return type of the delegate must be compatible with
1052                         // the anonymous type.   Instead of doing a pass to examine the block
1053                         // we satisfy the rule by setting the return type on the EmitContext
1054                         // to be the delegate type return type.
1055                         //
1056
1057                         try {
1058                                 int errors = Report.Errors;
1059                                 am = CompatibleMethod (ec, null, return_type, delegate_type);
1060                                 if (am != null && delegate_type != type && errors == Report.Errors)
1061                                         am = CreateExpressionTree (ec, delegate_type);
1062
1063                                 if (!ec.IsInProbingMode)
1064                                         compatibles.Add (type, am == null ? EmptyExpression.Null : am);
1065
1066                                 return am;
1067                         } catch (Exception e) {
1068                                 throw new InternalErrorException (e, loc);
1069                         }
1070                 }
1071
1072                 protected virtual Expression CreateExpressionTree (EmitContext ec, Type delegate_type)
1073                 {
1074                         return CreateExpressionTree (ec);
1075                 }
1076
1077                 public override Expression CreateExpressionTree (EmitContext ec)
1078                 {
1079                         Report.Error (1946, loc, "An anonymous method cannot be converted to an expression tree");
1080                         return null;
1081                 }
1082
1083                 protected virtual Parameters ResolveParameters (EmitContext ec, TypeInferenceContext tic, Type delegate_type)
1084                 {
1085                         AParametersCollection delegate_parameters = TypeManager.GetDelegateParameters (delegate_type);
1086
1087                         if (Parameters == Parameters.Undefined) {
1088                                 //
1089                                 // We provide a set of inaccessible parameters
1090                                 //
1091                                 Parameter[] fixedpars = new Parameter[delegate_parameters.Count];
1092
1093                                 for (int i = 0; i < delegate_parameters.Count; i++) {
1094                                         Parameter.Modifier i_mod = delegate_parameters.FixedParameters [i].ModFlags;
1095                                         if (i_mod == Parameter.Modifier.OUT) {
1096                                                 Report.Error (1688, loc, "Cannot convert anonymous " +
1097                                                                   "method block without a parameter list " +
1098                                                                   "to delegate type `{0}' because it has " +
1099                                                                   "one or more `out' parameters.",
1100                                                                   TypeManager.CSharpName (delegate_type));
1101                                                 return null;
1102                                         }
1103                                         fixedpars[i] = new Parameter (
1104                                                 null, null,
1105                                                 delegate_parameters.FixedParameters [i].ModFlags, null, loc);
1106                                 }
1107
1108                                 return Parameters.CreateFullyResolved (fixedpars, delegate_parameters.Types);
1109                         }
1110
1111                         if (!VerifyExplicitParameters (delegate_type, delegate_parameters, ec.IsInProbingMode)) {
1112                                 return null;
1113                         }
1114
1115                         return Parameters;
1116                 }
1117
1118                 public override Expression DoResolve (EmitContext ec)
1119                 {
1120                         if (!ec.IsAnonymousMethodAllowed) {
1121                                 Report.Error (1706, loc, "Anonymous methods and lambda expressions cannot be used in the current context");
1122                                 return null;
1123                         }
1124
1125                         //
1126                         // Set class type, set type
1127                         //
1128
1129                         eclass = ExprClass.Value;
1130
1131                         //
1132                         // This hack means `The type is not accessible
1133                         // anywhere', we depend on special conversion
1134                         // rules.
1135                         //
1136                         type = TypeManager.anonymous_method_type;
1137
1138                         if ((Parameters != null) && !Parameters.Resolve (ec))
1139                                 return null;
1140
1141                         // FIXME: The emitted code isn't very careful about reachability
1142                         // so, ensure we have a 'ret' at the end
1143                         if (ec.CurrentBranching != null &&
1144                             ec.CurrentBranching.CurrentUsageVector.IsUnreachable)
1145                                 ec.NeedReturnLabel ();
1146
1147                         return this;
1148                 }
1149
1150                 public override void Emit (EmitContext ec)
1151                 {
1152                         // nothing, as we only exist to not do anything.
1153                 }
1154
1155                 public static void Error_AddressOfCapturedVar (IVariableReference var, Location loc)
1156                 {
1157                         Report.Error (1686, loc,
1158                                 "Local variable or parameter `{0}' cannot have their address taken and be used inside an anonymous method or lambda expression",
1159                                 var.Name);
1160                 }
1161
1162                 public override string GetSignatureForError ()
1163                 {
1164                         return ExprClassName;
1165                 }
1166
1167                 protected AnonymousMethodBody CompatibleMethod (EmitContext ec, TypeInferenceContext tic, Type return_type, Type delegate_type)
1168                 {
1169                         Parameters p = ResolveParameters (ec, tic, delegate_type);
1170                         if (p == null)
1171                                 return null;
1172
1173                         ToplevelBlock b = ec.IsInProbingMode ? (ToplevelBlock) Block.PerformClone () : Block;
1174
1175                         AnonymousMethodBody anonymous = CompatibleMethodFactory (return_type, delegate_type, p, b);
1176                         if (!anonymous.Compatible (ec))
1177                                 return null;
1178
1179                         return anonymous;
1180                 }
1181
1182                 protected virtual AnonymousMethodBody CompatibleMethodFactory (Type return_type, Type delegate_type, Parameters p, ToplevelBlock b)
1183                 {
1184                         return new AnonymousMethodBody (p, b, return_type, delegate_type, loc);
1185                 }
1186
1187                 protected override void CloneTo (CloneContext clonectx, Expression t)
1188                 {
1189                         AnonymousMethodExpression target = (AnonymousMethodExpression) t;
1190
1191                         target.Block = (ToplevelBlock) clonectx.LookupBlock (Block);
1192                 }
1193         }
1194
1195         //
1196         // Abstract expression for any block which requires variables hoisting
1197         //
1198         public abstract class AnonymousExpression : Expression
1199         {
1200                 protected class AnonymousMethodMethod : Method
1201                 {
1202                         public readonly AnonymousExpression AnonymousMethod;
1203                         public readonly AnonymousMethodStorey Storey;
1204                         readonly string RealName;
1205
1206                         public AnonymousMethodMethod (DeclSpace parent, AnonymousExpression am, AnonymousMethodStorey storey,
1207                                                           GenericMethod generic, TypeExpr return_type,
1208                                                           int mod, string real_name, MemberName name,
1209                                                           Parameters parameters)
1210                                 : base (parent, generic, return_type, mod | Modifiers.COMPILER_GENERATED,
1211                                                 name, parameters, null)
1212                         {
1213                                 this.AnonymousMethod = am;
1214                                 this.Storey = storey;
1215                                 this.RealName = real_name;
1216
1217                                 Parent.PartialContainer.AddMethod (this);
1218                                 Block = am.Block;
1219                         }
1220
1221                         public override EmitContext CreateEmitContext (DeclSpace tc, ILGenerator ig)
1222                         {
1223                                 EmitContext aec = AnonymousMethod.aec;
1224                                 aec.ig = ig;
1225                                 aec.IsStatic = (ModFlags & Modifiers.STATIC) != 0;
1226                                 return aec;
1227                         }
1228
1229                         protected override bool ResolveMemberType ()
1230                         {
1231                                 if (!base.ResolveMemberType ())
1232                                         return false;
1233
1234                                 if (Storey != null && Storey.IsGeneric) {
1235                                         AnonymousMethodStorey gstorey = Storey.GetGenericStorey ();
1236                                         if (gstorey != null) {
1237                                                 if (!Parameters.IsEmpty) {
1238                                                         Type [] ptypes = Parameters.Types;
1239                                                         for (int i = 0; i < ptypes.Length; ++i)
1240                                                                 ptypes [i] = gstorey.MutateType (ptypes [i]);
1241                                                 }
1242
1243                                                 member_type = gstorey.MutateType (member_type);
1244                                         }
1245                                 }
1246
1247                                 return true;
1248                         }
1249
1250                         public override void Emit ()
1251                         {
1252                                 //
1253                                 // Before emitting any code we have to change all MVAR references to VAR
1254                                 // when the method is of generic type and has hoisted variables
1255                                 //
1256                                 if (Storey == Parent && Storey.IsGeneric) {
1257                                         AnonymousMethodStorey gstorey = Storey.GetGenericStorey ();
1258                                         if (gstorey != null) {
1259                                                 AnonymousMethod.aec.ReturnType = gstorey.MutateType (ReturnType);
1260                                                 block.MutateHoistedGenericType (gstorey);
1261                                         }
1262                                 }
1263
1264                                 if (MethodBuilder == null) {
1265                                         Define ();
1266                                 }
1267
1268                                 base.Emit ();
1269                         }
1270
1271                         public override void EmitExtraSymbolInfo (SourceMethod source)
1272                         {
1273                                 source.SetRealMethodName (RealName);
1274                         }
1275                 }
1276
1277                 //
1278                 // The block that makes up the body for the anonymous method
1279                 //
1280                 protected readonly ToplevelBlock Block;
1281
1282                 public Type ReturnType;
1283                 protected EmitContext aec;
1284
1285                 protected AnonymousExpression (ToplevelBlock block, Type return_type, Location loc)
1286                 {
1287                         this.ReturnType = return_type;
1288                         this.Block = block;
1289                         this.loc = loc;
1290                 }
1291
1292                 public abstract string ContainerType { get; }
1293                 public abstract bool IsIterator { get; }
1294                 public abstract AnonymousMethodStorey Storey { get; }
1295
1296                 public bool Compatible (EmitContext ec)
1297                 {
1298                         // TODO: Implement clone
1299                         aec = new EmitContext (
1300                                 ec.ResolveContext, ec.TypeContainer, ec.DeclContainer,
1301                                 Location, null, ReturnType,
1302                                 (ec.InUnsafe ? Modifiers.UNSAFE : 0), /* No constructor */ false);
1303
1304                         aec.CurrentAnonymousMethod = this;
1305                         aec.IsStatic = ec.IsStatic;
1306
1307                         IDisposable aec_dispose = null;
1308                         EmitContext.Flags flags = 0;
1309                         if (ec.InferReturnType)
1310                                 flags |= EmitContext.Flags.InferReturnType;
1311
1312                         if (ec.IsInProbingMode)
1313                                 flags |= EmitContext.Flags.ProbingMode;
1314
1315                         if (ec.IsInFieldInitializer)
1316                                 flags |= EmitContext.Flags.InFieldInitializer;
1317
1318                         if (ec.IsInUnsafeScope)
1319                                 flags |= EmitContext.Flags.InUnsafe;
1320
1321                         // HACK: Flag with 0 cannot be set
1322                         if (flags != 0)
1323                                 aec_dispose = aec.Set (flags);
1324
1325                         bool unreachable;
1326                         bool res = aec.ResolveTopBlock (ec, Block, Block.Parameters, null, out unreachable);
1327
1328                         if (ec.InferReturnType)
1329                                 ReturnType = aec.ReturnType;
1330
1331                         if (aec_dispose != null) {
1332                                 aec_dispose.Dispose ();
1333                         }
1334
1335                         return res;
1336                 }
1337
1338                 public void SetHasThisAccess ()
1339                 {
1340                         Block.HasCapturedThis = true;
1341                         ExplicitBlock b = Block.Parent.Explicit;
1342
1343                         while (b != null) {
1344                                 if (b.HasCapturedThis)
1345                                         return;
1346
1347                                 b.HasCapturedThis = true;
1348                                 b = b.Parent == null ? null : b.Parent.Explicit;
1349                         }
1350                 }
1351         }
1352
1353         public class AnonymousMethodBody : AnonymousExpression
1354         {
1355                 protected readonly Parameters parameters;
1356                 AnonymousMethodStorey storey;
1357
1358                 AnonymousMethodMethod method;
1359                 Field am_cache;
1360
1361                 static int unique_id;
1362
1363                 public AnonymousMethodBody (Parameters parameters,
1364                                         ToplevelBlock block, Type return_type, Type delegate_type,
1365                                         Location loc)
1366                         : base (block, return_type, loc)
1367                 {
1368                         this.type = delegate_type;
1369                         this.parameters = parameters;
1370                 }
1371
1372                 public override string ContainerType {
1373                         get { return "anonymous method"; }
1374                 }
1375
1376                 public override AnonymousMethodStorey Storey {
1377                         get { return storey; }
1378                 }
1379
1380                 public override bool IsIterator {
1381                         get { return false; }
1382                 }
1383
1384                 public override Expression CreateExpressionTree (EmitContext ec)
1385                 {
1386                         Report.Error (1945, loc, "An expression tree cannot contain an anonymous method expression");
1387                         return null;
1388                 }
1389
1390                 bool Define (EmitContext ec)
1391                 {
1392                         if (aec == null && !Compatible (ec))
1393                                 return false;
1394
1395                         return true;
1396                 }
1397
1398                 //
1399                 // Creates a host for the anonymous method
1400                 //
1401                 AnonymousMethodMethod DoCreateMethodHost (EmitContext ec)
1402                 {
1403                         //
1404                         // Anonymous method body can be converted to
1405                         //
1406                         // 1, an instance method in current scope when only `this' is hoisted
1407                         // 2, a static method in current scope when neither `this' nor any variable is hoisted
1408                         // 3, an instance method in compiler generated storey when any hoisted variable exists
1409                         //
1410
1411                         int modifiers;
1412                         if (Block.HasCapturedVariable || Block.HasCapturedThis) {
1413                                 storey = FindBestMethodStorey ();
1414                                 modifiers = storey != null ? Modifiers.INTERNAL : Modifiers.PRIVATE;
1415                         } else {
1416                                 if (ec.CurrentAnonymousMethod != null)
1417                                         storey = ec.CurrentAnonymousMethod.Storey;
1418
1419                                 modifiers = Modifiers.STATIC | Modifiers.PRIVATE;
1420                         }
1421
1422                         DeclSpace parent = storey != null ? storey : ec.TypeContainer;
1423
1424                         MemberCore mc = ec.ResolveContext as MemberCore;
1425                         string name = CompilerGeneratedClass.MakeName (parent != storey ? mc.Name : null,
1426                                 "m", null, unique_id++);
1427
1428                         MemberName member_name;
1429                         GenericMethod generic_method;
1430                         if (storey == null && mc.MemberName.IsGeneric) {
1431                                 member_name = new MemberName (name, mc.MemberName.TypeArguments.Clone (), Location);
1432
1433                                 generic_method = new GenericMethod (parent.NamespaceEntry, parent, member_name,
1434                                         new TypeExpression (ReturnType, Location), parameters);
1435
1436                                 ArrayList list = new ArrayList ();
1437                                 foreach (TypeParameter tparam in ((IMethodData)mc).GenericMethod.CurrentTypeParameters) {
1438                                         if (tparam.Constraints != null)
1439                                                 list.Add (tparam.Constraints.Clone ());
1440                                 }
1441                                 generic_method.SetParameterInfo (list);
1442                         } else {
1443                                 member_name = new MemberName (name, Location);
1444                                 generic_method = null;
1445                         }
1446
1447                         string real_name = String.Format (
1448                                 "{0}~{1}{2}", mc.GetSignatureForError (), GetSignatureForError (),
1449                                 parameters.GetSignatureForError ());
1450
1451                         return new AnonymousMethodMethod (parent,
1452                                 this, storey, generic_method, new TypeExpression (ReturnType, Location), modifiers,
1453                                 real_name, member_name, parameters);
1454                 }
1455
1456                 public override Expression DoResolve (EmitContext ec)
1457                 {
1458                         if (eclass == ExprClass.Invalid) {
1459                                 if (!Define (ec))
1460                                         return null;
1461                         }
1462
1463                         eclass = ExprClass.Value;
1464                         return this;
1465                 }
1466
1467                 public override void Emit (EmitContext ec)
1468                 {
1469                         //
1470                         // Use same anonymous method implementation for scenarios where same
1471                         // code is used from multiple blocks, e.g. field initializers
1472                         //
1473                         if (method == null) {
1474                                 //
1475                                 // Delay an anonymous method definition to avoid emitting unused code
1476                                 // for unreachable blocks or expression trees
1477                                 //
1478                                 method = DoCreateMethodHost (ec);
1479                                 method.Define ();
1480                         }
1481
1482                         bool is_static = (method.ModFlags & Modifiers.STATIC) != 0;
1483                         if (is_static && am_cache == null) {
1484                                 //
1485                                 // Creates a field cache to store delegate instance if it's not generic
1486                                 //
1487                                 if (!method.MemberName.IsGeneric) {
1488                                         TypeContainer parent = method.Parent.PartialContainer;
1489                                         int id = parent.Fields == null ? 0 : parent.Fields.Count;
1490                                         am_cache = new Field (parent, new TypeExpression (type, loc),
1491                                                 Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
1492                                                 new MemberName (CompilerGeneratedClass.MakeName (null, "f", "am$cache", id), loc), null);
1493                                         am_cache.Define ();
1494                                         parent.AddField (am_cache);
1495                                 } else {
1496                                         // TODO: Implement caching of generated generic static methods
1497                                         //
1498                                         // Idea:
1499                                         //
1500                                         // Some extra class is needed to capture variable generic type
1501                                         // arguments. Maybe we could re-use anonymous types, with a unique
1502                                         // anonymous method id, but they are quite heavy.
1503                                         //
1504                                         // Consider : "() => typeof(T);"
1505                                         //
1506                                         // We need something like
1507                                         // static class Wrap<Tn, Tm, DelegateType> {
1508                                         //              public static DelegateType cache;
1509                                         // }
1510                                         //
1511                                         // We then specialize local variable to capture all generic parameters
1512                                         // and delegate type, e.g. "Wrap<Ta, Tb, DelegateTypeInst> cache;"
1513                                         //
1514                                 }
1515                         }
1516
1517                         ILGenerator ig = ec.ig;
1518                         Label l_initialized = ig.DefineLabel ();
1519
1520                         if (am_cache != null) {
1521                                 ig.Emit (OpCodes.Ldsfld, am_cache.FieldBuilder);
1522                                 ig.Emit (OpCodes.Brtrue_S, l_initialized);
1523                         }
1524
1525                         //
1526                         // Load method delegate implementation
1527                         //
1528
1529                         if (is_static) {
1530                                 ig.Emit (OpCodes.Ldnull);
1531                         } else if (storey != null) {
1532                                 Expression e = storey.GetStoreyInstanceExpression (ec).Resolve (ec);
1533                                 if (e != null)
1534                                         e.Emit (ec);
1535                         } else {
1536                                 ig.Emit (OpCodes.Ldarg_0);
1537                         }
1538
1539                         MethodInfo delegate_method = method.MethodBuilder;
1540 #if GMCS_SOURCE
1541                         if (storey != null && storey.MemberName.IsGeneric) {
1542                                 Type t = storey.Instance.Type;
1543
1544                                 //
1545                                 // Mutate anonymous method instance type if we are in nested
1546                                 // hoisted generic anonymous method storey
1547                                 //
1548                                 if (ec.CurrentAnonymousMethod != null &&
1549                                         ec.CurrentAnonymousMethod.Storey != null &&
1550                                         ec.CurrentAnonymousMethod.Storey.IsGeneric) {
1551                                         t = storey.GetGenericStorey ().MutateType (t);
1552                                 }
1553
1554                                 delegate_method = TypeBuilder.GetMethod (t, delegate_method);
1555                         }
1556 #endif
1557                         ig.Emit (OpCodes.Ldftn, delegate_method);
1558
1559                         ConstructorInfo constructor_method = Delegate.GetConstructor (ec.ContainerType, type);
1560 #if MS_COMPATIBLE
1561             if (type.IsGenericType && type is TypeBuilder)
1562                 constructor_method = TypeBuilder.GetConstructor (type, constructor_method);
1563 #endif
1564                         ig.Emit (OpCodes.Newobj, constructor_method);
1565
1566                         if (am_cache != null) {
1567                                 ig.Emit (OpCodes.Stsfld, am_cache.FieldBuilder);
1568                                 ig.MarkLabel (l_initialized);
1569                                 ig.Emit (OpCodes.Ldsfld, am_cache.FieldBuilder);
1570                         }
1571                 }
1572
1573                 //
1574                 // Look for the best storey for this anonymous method
1575                 //
1576                 AnonymousMethodStorey FindBestMethodStorey ()
1577                 {
1578                         //
1579                         // Use the nearest parent block which has a storey
1580                         //
1581                         for (Block b = Block.Parent; b != null; b = b.Parent) {
1582                                 AnonymousMethodStorey s = b.Explicit.AnonymousMethodStorey;
1583                                 if (s != null)
1584                                         return s;
1585                         }
1586
1587                         return null;
1588                 }
1589
1590                 public override string GetSignatureForError ()
1591                 {
1592                         return TypeManager.CSharpName (type);
1593                 }
1594
1595                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1596                 {
1597                         type = storey.MutateType (type);
1598                 }
1599
1600                 public static void Reset ()
1601                 {
1602                         unique_id = 0;
1603                 }
1604         }
1605
1606         //
1607         // Anonymous type container
1608         //
1609         public class AnonymousTypeClass : CompilerGeneratedClass
1610         {
1611                 sealed class AnonymousParameters : Parameters
1612                 {
1613                         public AnonymousParameters (params Parameter[] parameters)
1614                                 : base (parameters)
1615                         {
1616                         }
1617
1618                         protected override void ErrorDuplicateName (Parameter p)
1619                         {
1620                                 Report.Error (833, p.Location, "`{0}': An anonymous type cannot have multiple properties with the same name",
1621                                         p.Name);
1622                         }
1623                 }
1624
1625                 static int types_counter;
1626                 public const string ClassNamePrefix = "<>__AnonType";
1627                 public const string SignatureForError = "anonymous type";
1628
1629                 readonly ArrayList parameters;
1630
1631                 private AnonymousTypeClass (DeclSpace parent, MemberName name, ArrayList parameters, Location loc)
1632                         : base (parent, name, (RootContext.EvalMode ? Modifiers.PUBLIC : 0) | Modifiers.SEALED)
1633                 {
1634                         this.parameters = parameters;
1635                 }
1636
1637                 public static AnonymousTypeClass Create (TypeContainer parent, ArrayList parameters, Location loc)
1638                 {
1639                         if (RootContext.Version <= LanguageVersion.ISO_2)
1640                                 Report.FeatureIsNotAvailable (loc, "anonymous types");
1641
1642                         string name = ClassNamePrefix + types_counter++;
1643
1644                         SimpleName [] t_args = new SimpleName [parameters.Count];
1645                         TypeParameterName [] t_params = new TypeParameterName [parameters.Count];
1646                         Parameter [] ctor_params = new Parameter [parameters.Count];
1647                         for (int i = 0; i < parameters.Count; ++i) {
1648                                 AnonymousTypeParameter p = (AnonymousTypeParameter) parameters [i];
1649
1650                                 t_args [i] = new SimpleName ("<" + p.Name + ">__T", p.Location);
1651                                 t_params [i] = new TypeParameterName (t_args [i].Name, null, p.Location);
1652                                 ctor_params [i] = new Parameter (t_args [i], p.Name, 0, null, p.Location);
1653                         }
1654
1655                         //
1656                         // Create generic anonymous type host with generic arguments
1657                         // named upon properties names
1658                         //
1659                         AnonymousTypeClass a_type = new AnonymousTypeClass (parent.NamespaceEntry.SlaveDeclSpace,
1660                                 new MemberName (name, new TypeArguments (t_params), loc), parameters, loc);
1661
1662                         if (parameters.Count > 0)
1663                                 a_type.SetParameterInfo (null);
1664
1665                         Constructor c = new Constructor (a_type, name, Modifiers.PUBLIC | Modifiers.DEBUGGER_HIDDEN,
1666                                 null, new AnonymousParameters (ctor_params), null, loc);
1667                         c.Block = new ToplevelBlock (c.Parameters, loc);
1668
1669                         //
1670                         // Create fields and contructor body with field initialization
1671                         //
1672                         bool error = false;
1673                         for (int i = 0; i < parameters.Count; ++i) {
1674                                 AnonymousTypeParameter p = (AnonymousTypeParameter) parameters [i];
1675
1676                                 Field f = new Field (a_type, t_args [i], Modifiers.PRIVATE | Modifiers.READONLY,
1677                                         new MemberName ("<" + p.Name + ">", p.Location), null);
1678
1679                                 if (!a_type.AddField (f)) {
1680                                         error = true;
1681                                         continue;
1682                                 }
1683
1684                                 c.Block.AddStatement (new StatementExpression (
1685                                         new SimpleAssign (new MemberAccess (new This (p.Location), f.Name),
1686                                                 c.Block.GetParameterReference (p.Name, p.Location))));
1687
1688                                 ToplevelBlock get_block = new ToplevelBlock (p.Location);
1689                                 get_block.AddStatement (new Return (
1690                                         new MemberAccess (new This (p.Location), f.Name), p.Location));
1691                                 Accessor get_accessor = new Accessor (get_block, 0, null, null, p.Location);
1692                                 Property prop = new Property (a_type, t_args [i], Modifiers.PUBLIC,
1693                                         new MemberName (p.Name, p.Location), null, get_accessor, null, false);
1694                                 a_type.AddProperty (prop);
1695                         }
1696
1697                         if (error)
1698                                 return null;
1699
1700                         a_type.AddConstructor (c);
1701                         return a_type;
1702                 }
1703
1704                 public static void Reset ()
1705                 {
1706                         types_counter = 0;
1707                 }
1708
1709                 protected override bool AddToContainer (MemberCore symbol, string name)
1710                 {
1711                         MemberCore mc = (MemberCore) defined_names [name];
1712
1713                         if (mc == null) {
1714                                 defined_names.Add (name, symbol);
1715                                 return true;
1716                         }
1717
1718                         Report.SymbolRelatedToPreviousError (mc);
1719                         return false;
1720                 }
1721
1722                 void DefineOverrides ()
1723                 {
1724                         Location loc = Location;
1725
1726                         Method equals = new Method (this, null, TypeManager.system_boolean_expr,
1727                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN, new MemberName ("Equals", loc),
1728                                 Mono.CSharp.Parameters.CreateFullyResolved (new Parameter (null, "obj", 0, null, loc), TypeManager.object_type), null);
1729
1730                         Method tostring = new Method (this, null, TypeManager.system_string_expr,
1731                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN, new MemberName ("ToString", loc),
1732                                 Mono.CSharp.Parameters.EmptyReadOnlyParameters, null);
1733
1734                         ToplevelBlock equals_block = new ToplevelBlock (equals.Parameters, loc);
1735                         TypeExpr current_type;
1736                         if (IsGeneric)
1737                                 current_type = new GenericTypeExpr (this, loc);
1738                         else
1739                                 current_type = new TypeExpression (TypeBuilder, loc);
1740
1741                         equals_block.AddVariable (current_type, "other", loc);
1742                         LocalVariableReference other_variable = new LocalVariableReference (equals_block, "other", loc);
1743
1744                         MemberAccess system_collections_generic = new MemberAccess (new MemberAccess (
1745                                 new QualifiedAliasMember ("global", "System", loc), "Collections", loc), "Generic", loc);
1746
1747                         Expression rs_equals = null;
1748                         Expression string_concat = new StringConstant ("{", loc);
1749                         Expression rs_hashcode = new IntConstant (-2128831035, loc);
1750                         for (int i = 0; i < parameters.Count; ++i) {
1751                                 AnonymousTypeParameter p = (AnonymousTypeParameter) parameters [i];
1752                                 Field f = (Field) Fields [i];
1753
1754                                 MemberAccess equality_comparer = new MemberAccess (new MemberAccess (
1755                                         system_collections_generic, "EqualityComparer",
1756                                                 new TypeArguments (new SimpleName (TypeParameters [i].Name, loc)), loc),
1757                                                 "Default", loc);
1758
1759                                 ArrayList arguments_equal = new ArrayList (2);
1760                                 arguments_equal.Add (new Argument (new MemberAccess (new This (f.Location), f.Name)));
1761                                 arguments_equal.Add (new Argument (new MemberAccess (other_variable, f.Name)));
1762
1763                                 Expression field_equal = new Invocation (new MemberAccess (equality_comparer,
1764                                         "Equals", loc), arguments_equal);
1765
1766                                 ArrayList arguments_hashcode = new ArrayList (1);
1767                                 arguments_hashcode.Add (new Argument (new MemberAccess (new This (f.Location), f.Name)));
1768                                 Expression field_hashcode = new Invocation (new MemberAccess (equality_comparer,
1769                                         "GetHashCode", loc), arguments_hashcode);
1770
1771                                 IntConstant FNV_prime = new IntConstant (16777619, loc);
1772                                 rs_hashcode = new Binary (Binary.Operator.Multiply,
1773                                         new Binary (Binary.Operator.ExclusiveOr, rs_hashcode, field_hashcode),
1774                                         FNV_prime);
1775
1776                                 Expression field_to_string = new Conditional (new Binary (Binary.Operator.Inequality,
1777                                         new MemberAccess (new This (f.Location), f.Name), new NullLiteral (loc)),
1778                                         new Invocation (new MemberAccess (
1779                                                 new MemberAccess (new This (f.Location), f.Name), "ToString"), null),
1780                                         new StringConstant (string.Empty, loc));
1781
1782                                 if (rs_equals == null) {
1783                                         rs_equals = field_equal;
1784                                         string_concat = new Binary (Binary.Operator.Addition,
1785                                                 string_concat,
1786                                                 new Binary (Binary.Operator.Addition,
1787                                                         new StringConstant (" " + p.Name + " = ", loc),
1788                                                         field_to_string));
1789                                         continue;
1790                                 }
1791
1792                                 //
1793                                 // Implementation of ToString () body using string concatenation
1794                                 //
1795                                 string_concat = new Binary (Binary.Operator.Addition,
1796                                         new Binary (Binary.Operator.Addition,
1797                                                 string_concat,
1798                                                 new StringConstant (", " + p.Name + " = ", loc)),
1799                                         field_to_string);
1800
1801                                 rs_equals = new Binary (Binary.Operator.LogicalAnd, rs_equals, field_equal);
1802                         }
1803
1804                         string_concat = new Binary (Binary.Operator.Addition,
1805                                 string_concat,
1806                                 new StringConstant (" }", loc));
1807
1808                         //
1809                         // Equals (object obj) override
1810                         //
1811                         equals_block.AddStatement (new StatementExpression (
1812                                 new SimpleAssign (other_variable,
1813                                         new As (equals_block.GetParameterReference ("obj", loc),
1814                                                 current_type, loc), loc)));
1815
1816                         Expression equals_test = new Binary (Binary.Operator.Inequality, other_variable, new NullLiteral (loc));
1817                         if (rs_equals != null)
1818                                 equals_test = new Binary (Binary.Operator.LogicalAnd, equals_test, rs_equals);
1819                         equals_block.AddStatement (new Return (equals_test, loc));
1820
1821                         equals.Block = equals_block;
1822                         equals.Define ();
1823                         AddMethod (equals);
1824
1825                         //
1826                         // GetHashCode () override
1827                         //
1828                         Method hashcode = new Method (this, null, TypeManager.system_int32_expr,
1829                                 Modifiers.PUBLIC | Modifiers.OVERRIDE | Modifiers.DEBUGGER_HIDDEN,
1830                                 new MemberName ("GetHashCode", loc),
1831                                 Mono.CSharp.Parameters.EmptyReadOnlyParameters, null);
1832
1833                         //
1834                         // Modified FNV with good avalanche behavior and uniform
1835                         // distribution with larger hash sizes.
1836                         //
1837                         // const int FNV_prime = 16777619;
1838                         // int hash = (int) 2166136261;
1839                         // foreach (int d in data)
1840                         //     hash = (hash ^ d) * FNV_prime;
1841                         // hash += hash << 13;
1842                         // hash ^= hash >> 7;
1843                         // hash += hash << 3;
1844                         // hash ^= hash >> 17;
1845                         // hash += hash << 5;
1846
1847                         ToplevelBlock hashcode_top = new ToplevelBlock (loc);
1848                         Block hashcode_block = new Block (hashcode_top);
1849                         hashcode_top.AddStatement (new Unchecked (hashcode_block));
1850
1851                         hashcode_block.AddVariable (TypeManager.system_int32_expr, "hash", loc);
1852                         LocalVariableReference hash_variable = new LocalVariableReference (hashcode_block, "hash", loc);
1853                         hashcode_block.AddStatement (new StatementExpression (
1854                                 new SimpleAssign (hash_variable, rs_hashcode)));
1855
1856                         hashcode_block.AddStatement (new StatementExpression (
1857                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1858                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (13, loc)))));
1859                         hashcode_block.AddStatement (new StatementExpression (
1860                                 new CompoundAssign (Binary.Operator.ExclusiveOr, hash_variable,
1861                                         new Binary (Binary.Operator.RightShift, hash_variable, new IntConstant (7, loc)))));
1862                         hashcode_block.AddStatement (new StatementExpression (
1863                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1864                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (3, loc)))));
1865                         hashcode_block.AddStatement (new StatementExpression (
1866                                 new CompoundAssign (Binary.Operator.ExclusiveOr, hash_variable,
1867                                         new Binary (Binary.Operator.RightShift, hash_variable, new IntConstant (17, loc)))));
1868                         hashcode_block.AddStatement (new StatementExpression (
1869                                 new CompoundAssign (Binary.Operator.Addition, hash_variable,
1870                                         new Binary (Binary.Operator.LeftShift, hash_variable, new IntConstant (5, loc)))));
1871
1872                         hashcode_block.AddStatement (new Return (hash_variable, loc));
1873                         hashcode.Block = hashcode_top;
1874                         hashcode.Define ();
1875                         AddMethod (hashcode);
1876
1877                         //
1878                         // ToString () override
1879                         //
1880
1881                         ToplevelBlock tostring_block = new ToplevelBlock (loc);
1882                         tostring_block.AddStatement (new Return (string_concat, loc));
1883                         tostring.Block = tostring_block;
1884                         tostring.Define ();
1885                         AddMethod (tostring);
1886                 }
1887
1888                 public override bool Define ()
1889                 {
1890                         if (!base.Define ())
1891                                 return false;
1892
1893                         DefineOverrides ();
1894                         return true;
1895                 }
1896
1897                 public override string GetSignatureForError ()
1898                 {
1899                         return SignatureForError;
1900                 }
1901
1902                 public ArrayList Parameters {
1903                         get {
1904                                 return parameters;
1905                         }
1906                 }
1907         }
1908 }