mcs/gmcs/anonymous.cs

   1 //
   2 // anonymous.cs: Support for anonymous methods
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximain.com)
   6 //
   7 // (C) 2003, 2004 Novell, Inc.
   8 //
   9 // TODO: Ideally, we should have the helper classes emited as a hierarchy to map
  10 // their nesting, and have the visibility set to private, instead of NestedAssembly
  11 //
  12 //
  13 //
  14
  15 using System;
  16 using System.Text;
  17 using System.Collections;
  18 using System.Reflection;
  19 using System.Reflection.Emit;
  20
  21 namespace Mono.CSharp {
  22
  23         public abstract class AnonymousContainer : Expression
  24         {
  25                 // Used to generate unique method names.
  26                 protected static int anonymous_method_count;
  27
  28                 // An array list of AnonymousMethodParameter or null
  29                 public Parameters Parameters;
  30
  31                 //
  32                 // The block that makes up the body for the anonymous mehtod
  33                 //
  34                 public ToplevelBlock Block;
  35
  36                 //
  37                 // The container block for this anonymous method.
  38                 //
  39                 public Block ContainingBlock;
  40
  41                 //
  42                 // The implicit method we create
  43                 //
  44                 public Method method;
  45
  46                 protected MethodInfo invoke_mb;
  47
  48                 // The emit context for the anonymous method
  49                 public EmitContext aec;
  50                 public InternalParameters amp;
  51                 public string[] TypeParameters;
  52                 public Type[] TypeArguments;
  53                 protected bool unreachable;
  54
  55                 //
  56                 // The modifiers applied to the method, we aggregate them
  57                 //
  58                 protected int method_modifiers = Modifiers.PRIVATE;
  59
  60                 //
  61                 // During the resolve stage of the anonymous method body,
  62                 // we discover the actual scope where we are hosted, or
  63                 // null to host the method in the same class
  64                 //
  65                 public ScopeInfo Scope;
  66
  67                 //
  68                 // Points to our container anonymous method if its present
  69                 //
  70                 public AnonymousContainer ContainerAnonymousMethod;
  71
  72                 protected AnonymousContainer (Parameters parameters, ToplevelBlock container,
  73                                               ToplevelBlock block, Location l)
  74                 {
  75                         Parameters = parameters;
  76                         Block = block;
  77                         loc = l;
  78
  79                         //
  80                         // The order is important: this setups the CaptureContext tree hierarchy.
  81                         //
  82                         container.SetHaveAnonymousMethods (l, this);
  83                         block.SetHaveAnonymousMethods (l, this);
  84                 }
  85
  86                 protected AnonymousContainer (Parameters parameters, ToplevelBlock container,
  87                                               Location l)
  88                 {
  89                         Parameters = parameters;
  90                         Block = new ToplevelBlock (container, Parameters, l);
  91                         loc = l;
  92
  93                         //
  94                         // The order is important: this setups the CaptureContext tree hierarchy.
  95                         //
  96                         container.SetHaveAnonymousMethods (loc, this);
  97                         Block.SetHaveAnonymousMethods (loc, this);
  98                 }
  99
 100                 public override Expression DoResolve (EmitContext ec)
 101                 {
 102                         //
 103                         // Set class type, set type
 104                         //
 105
 106                         eclass = ExprClass.Value;
 107
 108                         //
 109                         // This hack means `The type is not accessible
 110                         // anywhere', we depend on special conversion
 111                         // rules.
 112                         //
 113                         type = TypeManager.anonymous_method_type;
 114
 115                         return this;
 116                 }
 117
 118                 protected abstract bool CreateMethodHost (EmitContext ec);
 119
 120                 public abstract void CreateScopeType (EmitContext ec, ScopeInfo scope);
 121
 122                 public abstract Iterator Iterator {
 123                         get;
 124                 }
 125
 126                 public abstract bool IsIterator {
 127                         get;
 128                 }
 129         }
 130
 131         public class AnonymousMethod : AnonymousContainer
 132         {
 133                 public AnonymousMethod (Parameters parameters, ToplevelBlock container,
 134                                         ToplevelBlock block, Location l)
 135                         : base (parameters, container, block, l)
 136                 {
 137                 }
 138
 139                 public override Iterator Iterator {
 140                         get { return null; }
 141                 }
 142
 143                 public override bool IsIterator {
 144                         get { return false; }
 145                 }
 146
 147                 public override void Emit (EmitContext ec)
 148                 {
 149                         // nothing, as we only exist to not do anything.
 150                 }
 151
 152                 //
 153                 // Creates the host for the anonymous method
 154                 //
 155                 protected override bool CreateMethodHost (EmitContext ec)
 156                 {
 157                         //
 158                         // Crude hack follows: we replace the TypeBuilder during the
 159                         // definition to get the method hosted in the right class
 160                         //
 161
 162                         TypeBuilder current_type = ec.TypeContainer.TypeBuilder;
 163                         TypeBuilder type_host = (Scope == null ) // || Scope.ScopeTypeBuilder == null)
 164                                 ? current_type : Scope.ScopeTypeBuilder;
 165
 166                         if (current_type == null)
 167                                 throw new Exception ("The current_type is null");
 168
 169                         if (type_host == null)
 170                                 throw new Exception (String.Format ("Type host is null, Scope is {0}", Scope == null ? "null" : "Not null"));
 171
 172                         if (current_type != type_host)
 173                                 method_modifiers = Modifiers.INTERNAL;
 174
 175                         if (current_type == type_host && ec.IsStatic){
 176                                 if (ec.IsStatic){
 177                                         method_modifiers |= Modifiers.STATIC;
 178                                 }
 179                                 current_type = null;
 180                         }
 181
 182                         string name = "<#AnonymousMethod>" + anonymous_method_count++;
 183                         MemberName member_name;
 184
 185                         GenericMethod generic_method = null;
 186                         if (TypeParameters != null) {
 187                                 TypeArguments args = new TypeArguments (loc);
 188                                 foreach (string t in TypeParameters)
 189                                         args.Add (new SimpleName (t, loc));
 190
 191                                 member_name = new MemberName (name, args, loc);
 192
 193                                 generic_method = new GenericMethod (
 194                                         ec.DeclSpace.NamespaceEntry,
 195                                         (TypeContainer) ec.TypeContainer, member_name,
 196                                         new TypeExpression (invoke_mb.ReturnType, loc),
 197                                         Parameters);
 198
 199                                 generic_method.SetParameterInfo (null);
 200                         } else
 201                                 member_name = new MemberName (name, loc);
 202
 203                         method = new Method (
 204                                 (TypeContainer) ec.TypeContainer, generic_method,
 205                                 new TypeExpression (invoke_mb.ReturnType, loc),
 206                                 method_modifiers, false, member_name, Parameters, null);
 207                         method.Block = Block;
 208
 209                         //
 210                         // Swap the TypeBuilder while we define the method, then restore
 211                         //
 212                         if (current_type != null)
 213                                 ec.TypeContainer.TypeBuilder = type_host;
 214                         bool res = method.Define ();
 215                         if (current_type != null)
 216                                 ec.TypeContainer.TypeBuilder = current_type;
 217
 218                         return res;
 219                 }
 220
 221                 void Error_ParameterMismatch (Type t)
 222                 {
 223                         Report.Error (1661, loc, "Anonymous method could not be converted to delegate `" +
 224                                       "{0}' since there is a parameter mismatch", t);
 225         }
 226
 227                 //
 228                 // Returns true if this anonymous method can be implicitly
 229                 // converted to the delegate type `delegate_type'
 230                 //
 231                 public Expression Compatible (EmitContext ec, Type delegate_type, bool probe)
 232                 {
 233                         //
 234                         // At this point its the first time we know the return type that is
 235                         // needed for the anonymous method.  We create the method here.
 236                         //
 237
 238                         MethodGroupExpr invoke_mg = Delegate.GetInvokeMethod (ec, delegate_type, loc);
 239                         invoke_mb = (MethodInfo) invoke_mg.Methods [0];
 240                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 241
 242                         if (delegate_type.IsGenericInstance) {
 243                                 TypeArguments = TypeManager.GetTypeArguments (delegate_type);
 244
 245                                 Type def = delegate_type.GetGenericTypeDefinition ();
 246                                 Type[] tparam = TypeManager.GetTypeArguments (def);
 247                                 TypeParameters = new string [tparam.Length];
 248                                 for (int i = 0; i < tparam.Length; i++)
 249                                         TypeParameters [i] = tparam [i].Name;
 250                         }
 251
 252                         if (Parameters == null){
 253                                 int i, j;
 254
 255                                 //
 256                                 // We provide a set of inaccessible parameters
 257                                 //
 258                                 int params_idx = -1;
 259                                 for (i = 0; i < invoke_pd.Count; i++){
 260                                         if (invoke_pd.ParameterModifier (i) == Parameter.Modifier.PARAMS)
 261                                                 params_idx = i;
 262                                 }
 263                                 int n = invoke_pd.Count - (params_idx != -1 ? 1 : 0);
 264                                 Parameter [] fixedpars = new Parameter [n];
 265
 266                                 for (i =  j = 0; i < invoke_pd.Count; i++){
 267                                         if (invoke_pd.ParameterModifier (i) == Parameter.Modifier.PARAMS)
 268                                                 continue;
 269                                         fixedpars [j] = new Parameter (
 270                                                 new TypeExpression (invoke_pd.ParameterType (i), loc),
 271                                                 "+" + j, invoke_pd.ParameterModifier (i), null, loc);
 272                                         j++;
 273                                 }
 274
 275                                 Parameter variable = null;
 276                                 if (params_idx != -1){
 277                                         variable = new Parameter (
 278                                                 new TypeExpression (invoke_pd.ParameterType (params_idx), loc),
 279                                                 "+" + params_idx, invoke_pd.ParameterModifier (params_idx), null, loc);
 280                                 }
 281
 282                                 Parameters = new Parameters (fixedpars, variable);
 283                         }
 284
 285                         //
 286                         // First, parameter types of `delegate_type' must be compatible
 287                         // with the anonymous method.
 288                         //
 289                         amp = new InternalParameters (Parameters.GetParameterInfo (ec), Parameters);
 290
 291                         if (amp.Count != invoke_pd.Count){
 292                                 if (!probe){
 293                                         Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 294                                                 TypeManager.CSharpName (delegate_type), amp.Count);
 295                                         Error_ParameterMismatch (delegate_type);
 296                                 }
 297                                 return null;
 298                         }
 299
 300                         for (int i = 0; i < amp.Count; i++){
 301                                 Parameter.Modifier amp_mod = amp.ParameterModifier (i);
 302
 303                                 if (!probe) {
 304                                         if ((amp_mod & (Parameter.Modifier.OUT | Parameter.Modifier.REF)) != 0){
 305                                                 Report.Error (1677, loc, "Parameter `{0}' should not be declared with the `{1}' keyword",
 306                                                         i+1, amp.ModifierDesc (i));
 307                                                 Error_ParameterMismatch (delegate_type);
 308                                                 return null;
 309                                         }
 310
 311                                         if (amp_mod != invoke_pd.ParameterModifier (i)){
 312                                                 Report.Error (1676, loc, "Parameter `{0}' must be declared with the `{1}' keyword",
 313                                                         i+1, Parameter.GetModifierSignature (invoke_pd.ParameterModifier (i)));
 314                                                 Error_ParameterMismatch (delegate_type);
 315                                                 return null;
 316                                         }
 317
 318                                         if (amp.ParameterType (i) != invoke_pd.ParameterType (i)){
 319                                                 Report.Error (1678, loc, "Parameter `{0}' is declared as type `{1}' but should be `{2}'",
 320                                                         i+1,
 321                                                         TypeManager.CSharpName (amp.ParameterType (i)),
 322                                                         TypeManager.CSharpName (invoke_pd.ParameterType (i)));
 323                                                 Error_ParameterMismatch (delegate_type);
 324                                                 return null;
 325                                         }
 326                                 }
 327                         }
 328
 329                         //
 330                         // If we are only probing, return ourselves
 331                         //
 332                         if (probe)
 333                                 return this;
 334
 335                         //
 336                         // Second: the return type of the delegate must be compatible with
 337                         // the anonymous type.   Instead of doing a pass to examine the block
 338                         // we satisfy the rule by setting the return type on the EmitContext
 339                         // to be the delegate type return type.
 340                         //
 341
 342                         //MethodBuilder builder = method_data.MethodBuilder;
 343                         //ILGenerator ig = builder.GetILGenerator ();
 344
 345
 346                         aec = new EmitContext (
 347                                 ec.TypeContainer, ec.DeclSpace, loc, null,
 348                                 invoke_mb.ReturnType,
 349                                 /* REVIEW */ (ec.InIterator ? Modifiers.METHOD_YIELDS : 0) |
 350                                 (ec.InUnsafe ? Modifiers.UNSAFE : 0) |
 351                                 (ec.IsStatic ? Modifiers.STATIC : 0),
 352                                 /* No constructor */ false);
 353
 354                         aec.CurrentAnonymousMethod = this;
 355                         ContainerAnonymousMethod = ec.CurrentAnonymousMethod;
 356                         ContainingBlock = ec.CurrentBlock;
 357
 358                         if (aec.ResolveTopBlock (ec, Block, amp, null, out unreachable))
 359                                 return new AnonymousDelegate (this, delegate_type, loc).Resolve (ec);
 360
 361                         return null;
 362                 }
 363
 364                 public override string ExprClassName {
 365                         get {
 366                                 return "anonymous method";
 367                         }
 368                 }
 369
 370                 public MethodInfo GetMethodBuilder ()
 371                 {
 372                         MethodInfo builder = method.MethodData.MethodBuilder;
 373                         if (TypeArguments != null)
 374                                 return builder.MakeGenericMethod (TypeArguments);
 375                         else
 376                                 return builder;
 377                 }
 378
 379                 public override string GetSignatureForError ()
 380                 {
 381                         string s = TypeManager.CSharpSignature (invoke_mb);
 382                         return s.Substring (0, s.IndexOf (".Invoke("));
 383                 }
 384
 385                 public bool EmitMethod (EmitContext ec)
 386                 {
 387                         if (!CreateMethodHost (ec))
 388                                 return false;
 389
 390                         MethodBuilder builder = method.MethodData.MethodBuilder;
 391                         ILGenerator ig = builder.GetILGenerator ();
 392                         aec.ig = ig;
 393
 394                         Parameters.LabelParameters (aec, builder);
 395
 396                         //
 397                         // Adjust based on the computed state of the
 398                         // method from CreateMethodHost
 399
 400                         aec.MethodIsStatic = (method_modifiers & Modifiers.STATIC) != 0;
 401
 402                         aec.EmitMeta (Block, amp);
 403                         aec.EmitResolvedTopBlock (Block, unreachable);
 404                         return true;
 405                 }
 406
 407                 public override void CreateScopeType (EmitContext ec, ScopeInfo scope)
 408                 {
 409                         TypeBuilder container = ec.TypeContainer.TypeBuilder;
 410                         string name = String.Format ("<>AnonHelp<{0}>", scope.id);
 411
 412                         scope.ScopeTypeBuilder = container.DefineNestedType (
 413                                 name, TypeAttributes.AutoLayout | TypeAttributes.Class |
 414                                 TypeAttributes.NestedAssembly, TypeManager.object_type, null);
 415
 416                         Type [] constructor_types = TypeManager.NoTypes;
 417                         Parameters constructor_parameters = Parameters.EmptyReadOnlyParameters;
 418                         scope.ScopeConstructor = scope.ScopeTypeBuilder.DefineConstructor (
 419                                 MethodAttributes.Public | MethodAttributes.HideBySig |
 420                                 MethodAttributes.SpecialName | MethodAttributes.RTSpecialName,
 421                                 CallingConventions.HasThis, constructor_types);
 422                         InternalParameters parameter_info = new InternalParameters (constructor_types, constructor_parameters);
 423                         TypeManager.RegisterMethod (scope.ScopeConstructor, parameter_info, constructor_types);
 424
 425                         ILGenerator cig = scope.ScopeConstructor.GetILGenerator ();
 426                         cig.Emit (OpCodes.Ldarg_0);
 427                         cig.Emit (OpCodes.Call, TypeManager.object_ctor);
 428                         cig.Emit (OpCodes.Ret);
 429                 }
 430
 431                 public static void Error_AddressOfCapturedVar (string name, Location loc)
 432                 {
 433                         Report.Error (1686, loc,
 434                                 "Local variable `{0}' or its members cannot have their address taken and be used inside an anonymous method block",
 435                                 name);
 436                 }
 437         }
 438
 439         //
 440         // This will emit the code for the delegate, as well delegate creation on the host
 441         //
 442         public class AnonymousDelegate : DelegateCreation {
 443                 AnonymousMethod am;
 444
 445                 public AnonymousDelegate (AnonymousMethod am, Type target_type, Location l)
 446                 {
 447                         type = target_type;
 448                         loc = l;
 449                         this.am = am;
 450                 }
 451
 452                 public override Expression DoResolve (EmitContext ec)
 453                 {
 454                         eclass = ExprClass.Value;
 455
 456                         return this;
 457                 }
 458
 459                 public override void Emit (EmitContext ec)
 460                 {
 461                         if (!am.EmitMethod (ec))
 462                                 return;
 463
 464                         //
 465                         // Now emit the delegate creation.
 466                         //
 467                         if ((am.method.ModFlags & Modifiers.STATIC) == 0)
 468                                 delegate_instance_expression = new AnonymousInstance (am);
 469
 470                         Expression ml = Expression.MemberLookup (ec, type, ".ctor", loc);
 471                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 472                         delegate_method = am.GetMethodBuilder ();
 473                         base.Emit (ec);
 474                 }
 475
 476                 class AnonymousInstance : Expression {
 477                         AnonymousMethod am;
 478
 479                         public AnonymousInstance (AnonymousMethod am)
 480                         {
 481                                 this.am = am;
 482                                 eclass = ExprClass.Value;
 483                         }
 484
 485                         public override Expression DoResolve (EmitContext ec)
 486                         {
 487                                 return this;
 488                         }
 489
 490                         public override void Emit (EmitContext ec)
 491                         {
 492                                 am.aec.EmitMethodHostInstance (ec, am);
 493                         }
 494                 }
 495         }
 496
 497         class CapturedParameter {
 498                 public Type Type;
 499                 public FieldBuilder FieldBuilder;
 500                 public int Idx;
 501
 502                 public CapturedParameter (Type type, int idx)
 503                 {
 504                         Type = type;
 505                         Idx = idx;
 506                 }
 507         }
 508
 509         //
 510         // Here we cluster all the variables captured on a given scope, we also
 511         // keep some extra information that might be required on each scope.
 512         //
 513         public class ScopeInfo {
 514                 public CaptureContext CaptureContext;
 515                 public ScopeInfo ParentScope;
 516                 public Block ScopeBlock;
 517                 public bool NeedThis = false;
 518                 public bool HostsParameters = false;
 519
 520                 // For tracking the number of scopes created.
 521                 public int id;
 522                 static int count;
 523                 bool inited = false;
 524
 525                 ArrayList locals = new ArrayList ();
 526                 ArrayList children = new ArrayList ();
 527
 528                 //
 529                 // The types and fields generated
 530                 //
 531                 public TypeBuilder ScopeTypeBuilder;
 532                 public ConstructorBuilder ScopeConstructor;
 533                 public FieldBuilder THIS;
 534                 public FieldBuilder ParentLink;
 535
 536                 //
 537                 // Points to the object of type `ScopeTypeBuilder' that
 538                 // holds the data for the scope
 539                 //
 540                 LocalBuilder scope_instance;
 541
 542                 public ScopeInfo (CaptureContext cc, Block b)
 543                 {
 544                         CaptureContext = cc;
 545                         ScopeBlock = b;
 546                         id = count++;
 547
 548                         cc.AddScope (this);
 549                 }
 550
 551                 public void AddLocal (LocalInfo li)
 552                 {
 553                         if (locals.Contains (li))
 554                                 return;
 555
 556                         locals.Add (li);
 557 }
 558
 559                 public bool IsCaptured (LocalInfo li)
 560                 {
 561                         return locals.Contains (li);
 562                 }
 563
 564                 internal void AddChild (ScopeInfo si)
 565                 {
 566                         if (children.Contains (si))
 567                                 return;
 568
 569                         //
 570                         // If any of the current children should be a children of `si', move them there
 571                         //
 572                         ArrayList move_queue = null;
 573                         foreach (ScopeInfo child in children){
 574                                 if (child.ScopeBlock.IsChildOf (si.ScopeBlock)){
 575                                         if (move_queue == null)
 576                                                 move_queue = new ArrayList ();
 577                                         move_queue.Add (child);
 578                                         child.ParentScope = si;
 579                                         si.AddChild (child);
 580                                 }
 581                         }
 582
 583                         children.Add (si);
 584
 585                         if (move_queue != null){
 586                                 foreach (ScopeInfo child in move_queue){
 587                                         children.Remove (child);
 588                                 }
 589                         }
 590                 }
 591
 592                 static int indent = 0;
 593
 594                 void Pad ()
 595                 {
 596                         for (int i = 0; i < indent; i++)
 597                                 Console.Write ("    ");
 598                 }
 599
 600                 void EmitDebug ()
 601                 {
 602                         //Console.WriteLine (Environment.StackTrace);
 603                         Pad ();
 604                         Console.WriteLine ("START");
 605                         indent++;
 606                         Pad ();
 607                         Console.WriteLine ("NeedThis=" + NeedThis);
 608                         foreach (LocalInfo li in locals){
 609                                 Pad ();
 610                                 Console.WriteLine ("var {0}", MakeFieldName (li.Name));
 611                         }
 612
 613                         foreach (ScopeInfo si in children)
 614                                 si.EmitDebug ();
 615                         indent--;
 616                         Pad ();
 617                         Console.WriteLine ("END");
 618                 }
 619
 620                 public string MakeHelperName ()
 621                 {
 622                         return String.Format ("<>AnonHelp<{0}>", id);
 623                 }
 624
 625                 private string MakeFieldName (string local_name)
 626                 {
 627                         return "<" + id + ":" + local_name + ">";
 628                 }
 629
 630                 public void EmitScopeType (EmitContext ec)
 631                 {
 632                         // EmitDebug ();
 633
 634                         if (ScopeTypeBuilder != null)
 635                                 return;
 636
 637                         TypeBuilder container = ec.TypeContainer.TypeBuilder;
 638
 639                         CaptureContext.Host.CreateScopeType (ec, this);
 640
 641                         if (NeedThis)
 642                                 THIS = ScopeTypeBuilder.DefineField ("<>THIS", container, FieldAttributes.Assembly);
 643
 644                         if (ParentScope != null){
 645                                 if (ParentScope.ScopeTypeBuilder == null){
 646                                         throw new Exception (String.Format ("My parent has not been initialized {0} and {1}", ParentScope, this));
 647                                 }
 648
 649                                 if (ParentScope.ScopeTypeBuilder != ScopeTypeBuilder)
 650                                         ParentLink = ScopeTypeBuilder.DefineField ("<>parent", ParentScope.ScopeTypeBuilder,
 651                                                                                    FieldAttributes.Assembly);
 652                         }
 653
 654                         if (NeedThis && ParentScope != null)
 655                                 throw new Exception ("I was not expecting THIS && having a parent");
 656
 657                         foreach (LocalInfo info in locals)
 658                                 info.FieldBuilder = ScopeTypeBuilder.DefineField (
 659                                         MakeFieldName (info.Name), info.VariableType, FieldAttributes.Assembly);
 660
 661                         if (HostsParameters){
 662                                 Hashtable captured_parameters = CaptureContext.captured_parameters;
 663
 664                                 foreach (DictionaryEntry de in captured_parameters){
 665                                         string name = (string) de.Key;
 666                                         CapturedParameter cp = (CapturedParameter) de.Value;
 667                                         FieldBuilder fb;
 668
 669                                         fb = ScopeTypeBuilder.DefineField ("<p:" + name + ">", cp.Type, FieldAttributes.Assembly);
 670                                         cp.FieldBuilder = fb;
 671                                 }
 672                         }
 673
 674                         foreach (ScopeInfo si in children){
 675                                 si.EmitScopeType (ec);
 676                         }
 677                 }
 678
 679                 public void CloseTypes ()
 680                 {
 681                         RootContext.RegisterCompilerGeneratedType (ScopeTypeBuilder);
 682                         foreach (ScopeInfo si in children)
 683                                 si.CloseTypes ();
 684                 }
 685
 686                 //
 687                 // Emits the initialization code for the scope
 688                 //
 689                 public void EmitInitScope (EmitContext ec)
 690                 {
 691                         ILGenerator ig = ec.ig;
 692
 693                         if (inited)
 694                                 return;
 695
 696                         if (ScopeConstructor == null)
 697                                 throw new Exception ("ScopeConstructor is null for" + this.ToString ());
 698
 699                         if (!CaptureContext.Host.IsIterator) {
 700                                 scope_instance = ig.DeclareLocal (ScopeTypeBuilder);
 701                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) ScopeConstructor);
 702                                 ig.Emit (OpCodes.Stloc, scope_instance);
 703                         }
 704
 705                         if (THIS != null){
 706                                 if (CaptureContext.Host.IsIterator) {
 707                                         ig.Emit (OpCodes.Ldarg_0);
 708                                         ig.Emit (OpCodes.Ldarg_1);
 709                                 } else {
 710                                         ig.Emit (OpCodes.Ldloc, scope_instance);
 711                                         ig.Emit (OpCodes.Ldarg_0);
 712                                 }
 713                                 ig.Emit (OpCodes.Stfld, THIS);
 714                         }
 715
 716                         //
 717                         // Copy the parameter values, if any
 718                         //
 719                         int extra = ec.IsStatic ? 0 : 1;
 720                         if (CaptureContext.Host.IsIterator)
 721                                 extra++;
 722                         if (HostsParameters){
 723                                 Hashtable captured_parameters = CaptureContext.captured_parameters;
 724
 725                                 foreach (DictionaryEntry de in captured_parameters){
 726                                         CapturedParameter cp = (CapturedParameter) de.Value;
 727
 728                                         EmitScopeInstance (ig);
 729                                         ParameterReference.EmitLdArg (ig, cp.Idx + extra);
 730                                         ig.Emit (OpCodes.Stfld, cp.FieldBuilder);
 731                                 }
 732                         }
 733
 734                         if (ParentScope != null){
 735                                 if (!ParentScope.inited)
 736                                         ParentScope.EmitInitScope (ec);
 737
 738                                 if (ParentScope.ScopeTypeBuilder != ScopeTypeBuilder) {
 739                                         //
 740                                         // Only emit initialization in our capturecontext world
 741                                         //
 742                                         if (ParentScope.CaptureContext == CaptureContext){
 743                                                 EmitScopeInstance (ig);
 744                                                 ParentScope.EmitScopeInstance (ig);
 745                                                 ig.Emit (OpCodes.Stfld, ParentLink);
 746                                         } else {
 747                                                 EmitScopeInstance (ig);
 748                                                 ig.Emit (OpCodes.Ldarg_0);
 749                                                 ig.Emit (OpCodes.Stfld, ParentLink);
 750                                         }
 751                                 }
 752                         }
 753                         inited = true;
 754                 }
 755
 756                 public void EmitScopeInstance (ILGenerator ig)
 757                 {
 758                         if (CaptureContext.Host.IsIterator)
 759                                 ig.Emit (OpCodes.Ldarg_0);
 760                         else
 761                                 ig.Emit (OpCodes.Ldloc, scope_instance);
 762                 }
 763
 764                 static void DoPath (StringBuilder sb, ScopeInfo start)
 765                 {
 766                         if (start.ParentScope != null){
 767                                 DoPath (sb, start.ParentScope);
 768                                 sb.Append (", ");
 769                         }
 770                         sb.Append ((start.id).ToString ());
 771                 }
 772
 773                 public override string ToString ()
 774                 {
 775                         StringBuilder sb = new StringBuilder ();
 776
 777                         sb.Append ("{");
 778                         if (CaptureContext != null){
 779                                 sb.Append (CaptureContext.ToString ());
 780                                 sb.Append (":");
 781                         }
 782
 783                         DoPath (sb, this);
 784                         sb.Append ("}");
 785
 786                         return sb.ToString ();
 787                 }
 788         }
 789
 790         //
 791         // CaptureContext objects are created on demand if a method has
 792         // anonymous methods and kept on the ToplevelBlock.
 793         //
 794         // If they exist, all ToplevelBlocks in the containing block are
 795         // linked together (children pointing to their parents).
 796         //
 797         public class CaptureContext {
 798                 public static int count;
 799                 public int cc_id;
 800                 public Location loc;
 801
 802                 //
 803                 // Points to the toplevel block that owns this CaptureContext
 804                 //
 805                 ToplevelBlock toplevel_owner;
 806                 Hashtable scopes = new Hashtable ();
 807                 bool have_captured_vars = false;
 808                 bool referenced_this = false;
 809                 ScopeInfo topmost = null;
 810
 811                 //
 812                 // Captured fields
 813                 //
 814                 Hashtable captured_fields = new Hashtable ();
 815                 Hashtable captured_variables = new Hashtable ();
 816                 public Hashtable captured_parameters = new Hashtable ();
 817                 public AnonymousContainer Host;
 818
 819                 public CaptureContext (ToplevelBlock toplevel_owner, Location loc,
 820                                        AnonymousContainer host)
 821                 {
 822                         cc_id = count++;
 823                         this.toplevel_owner = toplevel_owner;
 824                         this.loc = loc;
 825
 826                         if (host != null)
 827                                 Host = host;
 828                 }
 829
 830                 void DoPath (StringBuilder sb, CaptureContext cc)
 831                 {
 832                         if (cc.ParentCaptureContext != null){
 833                                 DoPath (sb, cc.ParentCaptureContext);
 834                                 sb.Append (".");
 835                         }
 836                         sb.Append (cc.cc_id.ToString ());
 837                 }
 838
 839                 public void ReParent (ToplevelBlock new_toplevel, AnonymousContainer new_host)
 840                 {
 841                         toplevel_owner = new_toplevel;
 842                         Host = new_host;
 843
 844                         for (CaptureContext cc = ParentCaptureContext; cc != null;
 845                              cc = cc.ParentCaptureContext) {
 846                                 cc.Host = new_host;
 847                         }
 848                 }
 849
 850                 public override string ToString ()
 851                 {
 852                         StringBuilder sb = new StringBuilder ();
 853                         sb.Append ("[");
 854                         DoPath (sb, this);
 855                         sb.Append ("]");
 856                         return sb.ToString ();
 857                 }
 858
 859                 public ToplevelBlock ParentToplevel {
 860                         get {
 861                                 return toplevel_owner.Container;
 862                         }
 863                 }
 864
 865                 public CaptureContext ParentCaptureContext {
 866                         get {
 867                                 ToplevelBlock parent = ParentToplevel;
 868
 869                                 return (parent == null) ? null : parent.CaptureContext;
 870                         }
 871                 }
 872
 873                 // Returns the deepest of two scopes
 874                 public ScopeInfo Deepest (ScopeInfo a, ScopeInfo b)
 875                 {
 876                         ScopeInfo p;
 877
 878                         if (a == null)
 879                                 return b;
 880                         if (b == null)
 881                                 return a;
 882                         if (a == b)
 883                                 return a;
 884
 885                         //
 886                         // If they Scopes are on the same CaptureContext, we do the double
 887                         // checks just so if there is an invariant change in the future,
 888                         // we get the exception at the end
 889                         //
 890                         for (p = a; p != null; p = p.ParentScope)
 891                                 if (p == b)
 892                                         return a;
 893
 894                         for (p = b; p != null; p = p.ParentScope)
 895                                 if (p == a)
 896                                         return b;
 897
 898                         CaptureContext ca = a.CaptureContext;
 899                         CaptureContext cb = b.CaptureContext;
 900
 901                         for (CaptureContext c = ca; c != null; c = c.ParentCaptureContext)
 902                                 if (c == cb)
 903                                         return a;
 904
 905                         for (CaptureContext c = cb; c != null; c = c.ParentCaptureContext)
 906                                 if (c == ca)
 907                                         return b;
 908                         throw new Exception ("Should never be reached");
 909                 }
 910
 911                 void AdjustMethodScope (AnonymousContainer am, ScopeInfo scope)
 912                 {
 913                         am.Scope = Deepest (am.Scope, scope);
 914                 }
 915
 916                 void LinkScope (ScopeInfo scope, int id)
 917                 {
 918                         ScopeInfo parent = (ScopeInfo) scopes [id];
 919                         scope.ParentScope = parent;
 920                         parent.AddChild (scope);
 921
 922                         if (scope == topmost)
 923                                 topmost = parent;
 924                 }
 925
 926                 public void AddLocal (AnonymousContainer am, LocalInfo li)
 927                 {
 928                         if (li.Block.Toplevel != toplevel_owner){
 929                                 ParentCaptureContext.AddLocal (am, li);
 930                                 return;
 931                         }
 932                         int block_id = li.Block.ID;
 933                         ScopeInfo scope;
 934                         if (scopes [block_id] == null){
 935                                 scope = new ScopeInfo (this, li.Block);
 936                                 scopes [block_id] = scope;
 937                         } else
 938                                 scope = (ScopeInfo) scopes [block_id];
 939
 940                         if (topmost == null){
 941                                 topmost = scope;
 942                         } else {
 943                                 // Link to parent
 944
 945                                 for (Block b = scope.ScopeBlock.Parent; b != null; b = b.Parent){
 946                                         if (scopes [b.ID] != null){
 947                                                 LinkScope (scope, b.ID);
 948                                                 break;
 949                                         }
 950                                 }
 951
 952                                 if (scope.ParentScope == null && ParentCaptureContext != null){
 953                                         CaptureContext pcc = ParentCaptureContext;
 954
 955                                         for (Block b = am.ContainingBlock; b != null; b = b.Parent){
 956                                                 if (pcc.scopes [b.ID] != null){
 957                                                         pcc.LinkScope (scope, b.ID);
 958                                                         break;
 959                                                 }
 960                                         }
 961                                 }
 962                         }
 963
 964                         //
 965                         // Adjust the owner
 966                         //
 967                         if (Host != null)
 968                                 AdjustMethodScope (Host, topmost);
 969
 970                         //
 971                         // Adjust the user
 972                         //
 973                         AdjustMethodScope (am, scope);
 974
 975                         if (captured_variables [li] != null)
 976                                 return;
 977
 978                         have_captured_vars = true;
 979                         captured_variables [li] = li;
 980                         scope.AddLocal (li);
 981                 }
 982
 983                 //
 984                 // Retursn the CaptureContext for the block that defines the parameter `name'
 985                 //
 986                 static CaptureContext _ContextForParameter (ToplevelBlock current, string name)
 987                 {
 988                         ToplevelBlock container = current.Container;
 989                         if (container != null){
 990                                 CaptureContext cc = _ContextForParameter (container, name);
 991                                 if (cc != null)
 992                                         return cc;
 993                         }
 994                         if (current.IsParameterReference (name))
 995                                 return current.ToplevelBlockCaptureContext;
 996                         return null;
 997                 }
 998
 999                 static CaptureContext ContextForParameter (ToplevelBlock current, string name)
1000                 {
1001                         CaptureContext cc = _ContextForParameter (current, name);
1002                         if (cc == null)
1003                                 throw new Exception (String.Format ("request for parameteter {0} failed: not found", name));
1004                         return cc;
1005                 }
1006
1007                 //
1008                 // Records the captured parameter at the appropriate CaptureContext
1009                 //
1010                 public void AddParameter (EmitContext ec, AnonymousContainer am,
1011                                           string name, Type t, int idx)
1012                 {
1013                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
1014
1015                         cc.AddParameterToContext (am, name, t, idx);
1016                 }
1017
1018                 //
1019                 // Records the parameters in the context
1020                 //
1021                 public void AddParameterToContext (AnonymousContainer am, string name, Type t, int idx)
1022                 {
1023                         if (captured_parameters == null)
1024                                 captured_parameters = new Hashtable ();
1025                         if (captured_parameters [name] != null)
1026                                 return;
1027                         captured_parameters [name] = new CapturedParameter (t, idx);
1028
1029                         if (topmost == null){
1030                                 //
1031                                 // Create one ScopeInfo, if there are none.
1032                                 //
1033                                 topmost = new ScopeInfo (this, toplevel_owner);
1034                                 scopes [toplevel_owner.ID] = topmost;
1035                         } else {
1036                                 //
1037                                 // If the topmost ScopeInfo is not at the topblock level, insert
1038                                 // a new ScopeInfo there.
1039                                 //
1040                                 // FIXME: This code probably should be evolved to be like the code
1041                                 // in AddLocal
1042                                 //
1043                                 if (topmost.ScopeBlock != toplevel_owner){
1044                                         ScopeInfo par_si = new ScopeInfo (this, toplevel_owner);
1045                                         ScopeInfo old_top = topmost;
1046                                         scopes [toplevel_owner.ID] = topmost;
1047                                         topmost.ParentScope = par_si;
1048                                         topmost = par_si;
1049                                         topmost.AddChild (old_top);
1050                                 }
1051                         }
1052
1053                         topmost.HostsParameters = true;
1054                         AdjustMethodScope (am, topmost);
1055                 }
1056
1057                 //
1058                 // Captured fields are only recorded on the topmost CaptureContext, because that
1059                 // one is the one linked to the owner of instance fields
1060                 //
1061                 public void AddField (EmitContext ec, AnonymousContainer am, FieldExpr fe)
1062                 {
1063                         if (fe.FieldInfo.IsStatic)
1064                                 throw new Exception ("Attempt to register a static field as a captured field");
1065                         CaptureContext parent = ParentCaptureContext;
1066                         if (parent != null) {
1067                                 parent.AddField (ec, am, fe);
1068                                 return;
1069                         }
1070
1071                         if (topmost == null){
1072                                 //
1073                                 // Create one ScopeInfo, if there are none.
1074                                 //
1075                                 topmost = new ScopeInfo (this, toplevel_owner);
1076                                 scopes [toplevel_owner.ID] = topmost;
1077                         }
1078
1079                         AdjustMethodScope (am, topmost);
1080                 }
1081
1082                 public void CaptureThis (AnonymousContainer am)
1083                 {
1084                         CaptureContext parent = ParentCaptureContext;
1085                         if (parent != null) {
1086                                 parent.CaptureThis (am);
1087                                 return;
1088                         }
1089                         referenced_this = true;
1090
1091                         if (topmost == null){
1092                                 //
1093                                 // Create one ScopeInfo, if there are none.
1094                                 //
1095                                 topmost = new ScopeInfo (this, toplevel_owner);
1096                                 scopes [toplevel_owner.ID] = topmost;
1097
1098                                 AdjustMethodScope (am, topmost);
1099                         }
1100                 }
1101
1102                 public bool HaveCapturedVariables {
1103                         get {
1104                                 return have_captured_vars;
1105                         }
1106                 }
1107
1108                 public bool HaveCapturedFields {
1109                         get {
1110                                 CaptureContext parent = ParentCaptureContext;
1111                                 if (parent != null)
1112                                         return parent.HaveCapturedFields;
1113                                 return captured_fields.Count > 0;
1114                         }
1115                 }
1116
1117                 public bool IsCaptured (LocalInfo local)
1118                 {
1119                         foreach (ScopeInfo si in scopes.Values){
1120                                 if (si.IsCaptured (local))
1121                                         return true;
1122                         }
1123                         return false;
1124                 }
1125
1126                 //
1127                 // Returns whether the parameter is captured
1128                 //
1129                 public bool IsParameterCaptured (string name)
1130                 {
1131                         if (ParentCaptureContext != null && ParentCaptureContext.IsParameterCaptured (name))
1132                                 return true;
1133
1134                         if (captured_parameters != null)
1135                                 return captured_parameters [name] != null;
1136                         return false;
1137                 }
1138
1139                 public void EmitAnonymousHelperClasses (EmitContext ec)
1140                 {
1141                         if (topmost != null){
1142                                 topmost.NeedThis = HaveCapturedFields || referenced_this;
1143                                 topmost.EmitScopeType (ec);
1144                         }
1145                 }
1146
1147                 public void CloseAnonymousHelperClasses ()
1148                 {
1149                         if (topmost != null)
1150                                 topmost.CloseTypes ();
1151                 }
1152
1153                 public void EmitInitScope (EmitContext ec)
1154                 {
1155                         EmitAnonymousHelperClasses (ec);
1156                         if (topmost != null)
1157                                 topmost.EmitInitScope (ec);
1158                 }
1159
1160                 ScopeInfo GetScopeFromBlock (EmitContext ec, Block b)
1161                 {
1162                         ScopeInfo si;
1163
1164                         si = (ScopeInfo) scopes [b.ID];
1165                         if (si == null)
1166                                 throw new Exception ("Si is null for block " + b.ID);
1167                         si.EmitInitScope (ec);
1168
1169                         return si;
1170                 }
1171
1172                 //
1173                 // Emits the opcodes necessary to load the instance of the captured
1174                 // variable in `li'
1175                 //
1176                 public void EmitCapturedVariableInstance (EmitContext ec, LocalInfo li,
1177                                                           AnonymousContainer am)
1178                 {
1179                         ILGenerator ig = ec.ig;
1180                         ScopeInfo si;
1181
1182                         if (li.Block.Toplevel == toplevel_owner){
1183                                 si = GetScopeFromBlock (ec, li.Block);
1184                                 si.EmitScopeInstance (ig);
1185                                 return;
1186                         }
1187
1188                         si = am.Scope;
1189                         ig.Emit (OpCodes.Ldarg_0);
1190                         if (si != null){
1191                                 if (am.IsIterator && (si.ScopeBlock.Toplevel == li.Block.Toplevel)) {
1192                                         return;
1193                                 }
1194
1195                                 while (si.ScopeBlock.ID != li.Block.ID){
1196                                         if (si.ParentLink != null)
1197                                                 ig.Emit (OpCodes.Ldfld, si.ParentLink);
1198                                         si = si.ParentScope;
1199                                         if (si == null) {
1200                                                 si = am.Scope;
1201                                                 Console.WriteLine ("Target: {0} {1}", li.Block.ID, li.Name);
1202                                                 while (si.ScopeBlock.ID != li.Block.ID){
1203                                                         Console.WriteLine ("Trying: {0}", si.ScopeBlock.ID);
1204                                                         si = si.ParentScope;
1205                                                 }
1206
1207                                                 throw new Exception (
1208                                                              String.Format ("Never found block {0} starting at {1} while looking up {2}",
1209                                                                             li.Block.ID, am.Scope.ScopeBlock.ID, li.Name));
1210                                         }
1211                                 }
1212                         }
1213                 }
1214
1215                 //
1216                 // Internal routine that loads the instance to reach parameter `name'
1217                 //
1218                 void EmitParameterInstance (EmitContext ec, string name)
1219                 {
1220                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
1221                         if (cc != this){
1222                                 cc.EmitParameterInstance (ec, name);
1223                                 return;
1224                         }
1225
1226                         CapturedParameter par_info = (CapturedParameter) captured_parameters [name];
1227                         if (par_info != null){
1228                                 //
1229                                 // FIXME: implementing this.
1230                                 //
1231                         }
1232                         ILGenerator ig = ec.ig;
1233
1234                         ScopeInfo si;
1235
1236                         if (ec.CurrentBlock.Toplevel == toplevel_owner) {
1237                                 si = GetScopeFromBlock (ec, toplevel_owner);
1238                                 si.EmitScopeInstance (ig);
1239                         } else {
1240                                 si = ec.CurrentAnonymousMethod.Scope;
1241                                 ig.Emit (OpCodes.Ldarg_0);
1242                         }
1243
1244                         if (si != null){
1245                                 while (si.ParentLink != null) {
1246                                         ig.Emit (OpCodes.Ldfld, si.ParentLink);
1247                                         si = si.ParentScope;
1248                                 }
1249                         }
1250                 }
1251
1252                 //
1253                 // Emits the code necessary to load the parameter named `name' within
1254                 // an anonymous method.
1255                 //
1256                 public void EmitParameter (EmitContext ec, string name)
1257                 {
1258                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
1259                         if (cc != this){
1260                                 cc.EmitParameter (ec, name);
1261                                 return;
1262                         }
1263                         EmitParameterInstance (ec, name);
1264                         CapturedParameter par_info = (CapturedParameter) captured_parameters [name];
1265                         if (par_info != null){
1266                                 //
1267                                 // FIXME: implementing this.
1268                                 //
1269                         }
1270                         ec.ig.Emit (OpCodes.Ldfld, par_info.FieldBuilder);
1271                 }
1272
1273                 //
1274                 // Implements the assignment of `source' to the paramenter named `name' within
1275                 // an anonymous method.
1276                 //
1277                 public void EmitAssignParameter (EmitContext ec, string name, Expression source, bool leave_copy, bool prepare_for_load)
1278                 {
1279                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
1280                         if (cc != this){
1281                                 cc.EmitAssignParameter (ec, name, source, leave_copy, prepare_for_load);
1282                                 return;
1283                         }
1284                         ILGenerator ig = ec.ig;
1285                         CapturedParameter par_info = (CapturedParameter) captured_parameters [name];
1286
1287                         EmitParameterInstance (ec, name);
1288                         source.Emit (ec);
1289                         if (leave_copy)
1290                                 ig.Emit (OpCodes.Dup);
1291                         ig.Emit (OpCodes.Stfld, par_info.FieldBuilder);
1292                 }
1293
1294                 //
1295                 // Emits the address for the parameter named `name' within
1296                 // an anonymous method.
1297                 //
1298                 public void EmitAddressOfParameter (EmitContext ec, string name)
1299                 {
1300                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
1301                         if (cc != this){
1302                                 cc.EmitAddressOfParameter (ec, name);
1303                                 return;
1304                         }
1305                         EmitParameterInstance (ec, name);
1306                         CapturedParameter par_info = (CapturedParameter) captured_parameters [name];
1307                         ec.ig.Emit (OpCodes.Ldflda, par_info.FieldBuilder);
1308                 }
1309
1310                 //
1311                 // The following methods are only invoked on the host for the
1312                 // anonymous method.
1313                 //
1314                 public void EmitMethodHostInstance (EmitContext target, AnonymousContainer am)
1315                 {
1316                         ILGenerator ig = target.ig;
1317                         ScopeInfo si = am.Scope;
1318
1319                         if (si == null){
1320                                 ig.Emit (OpCodes.Ldarg_0);
1321                                 return;
1322                         }
1323
1324                         si.EmitInitScope (target);
1325                         si.EmitScopeInstance (ig);
1326                 }
1327
1328                 ArrayList all_scopes = new ArrayList ();
1329
1330                 public void AddScope (ScopeInfo si)
1331                 {
1332                         all_scopes.Add (si);
1333                         toplevel_owner.RegisterCaptureContext (this);
1334                 }
1335
1336                 //
1337                 // Links any scopes that were not linked previously
1338                 //
1339                 public void AdjustScopes ()
1340                 {
1341                         foreach (ScopeInfo scope in all_scopes){
1342                                 if (scope.ParentScope != null)
1343                                         continue;
1344
1345                                 for (Block b = scope.ScopeBlock.Parent; b != null; b = b.Parent){
1346                                         if (scopes [b.ID] != null){
1347                                                 LinkScope (scope, b.ID);
1348                                                 break;
1349                                         }
1350                                 }
1351
1352                                 if (scope.ParentScope == null && ParentCaptureContext != null){
1353                                         CaptureContext pcc = ParentCaptureContext;
1354
1355                                         for (Block b = Host.ContainingBlock; b != null; b = b.Parent){
1356                                                 if (pcc.scopes [b.ID] != null){
1357                                                         pcc.LinkScope (scope, b.ID);
1358                                                         break;
1359                                                 }
1360                                         }
1361                                 }
1362                         }
1363                 }
1364         }
1365 }