mcs/mcs/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                 protected bool unreachable;
  52
  53                 //
  54                 // The modifiers applied to the method, we aggregate them
  55                 //
  56                 protected int method_modifiers = Modifiers.PRIVATE;
  57
  58                 //
  59                 // During the resolve stage of the anonymous method body,
  60                 // we discover the actual scope where we are hosted, or
  61                 // null to host the method in the same class
  62                 //
  63                 public ScopeInfo Scope;
  64
  65                 //
  66                 // Points to our container anonymous method if its present
  67                 //
  68                 public AnonymousContainer ContainerAnonymousMethod;
  69
  70                 protected AnonymousContainer (Parameters parameters, ToplevelBlock container,
  71                                               ToplevelBlock block, Location l)
  72                 {
  73                         Parameters = parameters;
  74                         Block = block;
  75                         loc = l;
  76
  77                         //
  78                         // The order is important: this setups the CaptureContext tree hierarchy.
  79                         //
  80                         if (container == null) {
  81                                 Report.Error (1706, l, "Anonymous methods are not allowed in attribute declaration");
  82                                 return;
  83                         }
  84                         container.SetHaveAnonymousMethods (l, this);
  85                         block.SetHaveAnonymousMethods (l, this);
  86                 }
  87
  88                 protected AnonymousContainer (Parameters parameters, ToplevelBlock container,
  89                                               Location l):
  90                         this (parameters, container, new ToplevelBlock (container, parameters, l), l)
  91                 {
  92                 }
  93
  94                 public override Expression DoResolve (EmitContext ec)
  95                 {
  96                         //
  97                         // Set class type, set type
  98                         //
  99
 100                         eclass = ExprClass.Value;
 101
 102                         //
 103                         // This hack means `The type is not accessible
 104                         // anywhere', we depend on special conversion
 105                         // rules.
 106                         //
 107                         type = TypeManager.anonymous_method_type;
 108
 109                         return this;
 110                 }
 111
 112                 protected abstract bool CreateMethodHost (EmitContext ec);
 113
 114                 public abstract void CreateScopeType (EmitContext ec, ScopeInfo scope);
 115
 116                 public abstract bool IsIterator {
 117                         get;
 118                 }
 119         }
 120
 121         public class AnonymousMethod : AnonymousContainer
 122         {
 123                 public AnonymousMethod (Parameters parameters, ToplevelBlock container,
 124                                         ToplevelBlock block, Location l)
 125                         : base (parameters, container, block, l)
 126                 {
 127                 }
 128
 129                 public override bool IsIterator {
 130                         get { return false; }
 131                 }
 132
 133                 public override void Emit (EmitContext ec)
 134                 {
 135                         // nothing, as we only exist to not do anything.
 136                 }
 137
 138                 //
 139                 // Creates the host for the anonymous method
 140                 //
 141                 protected override bool CreateMethodHost (EmitContext ec)
 142                 {
 143                         //
 144                         // Crude hack follows: we replace the TypeBuilder during the
 145                         // definition to get the method hosted in the right class
 146                         //
 147
 148                         TypeBuilder current_type = ec.TypeContainer.TypeBuilder;
 149                         TypeBuilder type_host = (Scope == null ) // || Scope.ScopeTypeBuilder == null)
 150                                 ? current_type : Scope.ScopeTypeBuilder;
 151
 152                         if (current_type == null)
 153                                 throw new Exception ("The current_type is null");
 154
 155                         if (type_host == null)
 156                                 throw new Exception (String.Format ("Type host is null, Scope is {0}", Scope == null ? "null" : "Not null"));
 157
 158                         if (current_type != type_host)
 159                                 method_modifiers = Modifiers.INTERNAL;
 160
 161                         if (current_type == type_host && ec.IsStatic){
 162                                 method_modifiers |= Modifiers.STATIC;
 163                                 current_type = null;
 164                         }
 165
 166                         method = new Method (
 167                                 (TypeContainer) ec.TypeContainer,
 168                                 new TypeExpression (invoke_mb.ReturnType, loc),
 169                                 method_modifiers, false, new MemberName ("<#AnonymousMethod>" + anonymous_method_count++, loc),
 170                                 Parameters, null);
 171                         method.Block = Block;
 172
 173                         //
 174                         // Swap the TypeBuilder while we define the method, then restore
 175                         //
 176                         if (current_type != null)
 177                                 ec.TypeContainer.TypeBuilder = type_host;
 178                         bool res = method.Define ();
 179                         if (current_type != null)
 180                                 ec.TypeContainer.TypeBuilder = current_type;
 181                         return res;
 182                 }
 183
 184                 void Error_ParameterMismatch (Type t)
 185                 {
 186                         Report.Error (1661, loc, "Anonymous method could not be converted to delegate `" +
 187                                       "{0}' since there is a parameter mismatch", TypeManager.CSharpName (t));
 188                 }
 189
 190                 //
 191                 // Returns true if this anonymous method can be implicitly
 192                 // converted to the delegate type `delegate_type'
 193                 //
 194                 public Expression Compatible (EmitContext ec, Type delegate_type, bool probe)
 195                 {
 196                         //
 197                         // At this point its the first time we know the return type that is
 198                         // needed for the anonymous method.  We create the method here.
 199                         //
 200
 201                         invoke_mb = (MethodInfo) Delegate.GetInvokeMethod (ec, delegate_type, loc);
 202                         ParameterData invoke_pd = TypeManager.GetParameterData (invoke_mb);
 203
 204                         if (Parameters == null){
 205                                 int i, j;
 206
 207                                 //
 208                                 // We provide a set of inaccessible parameters
 209                                 //
 210                                 int params_idx = -1;
 211                                 for (i = 0; i < invoke_pd.Count; i++){
 212                                         if (invoke_pd.ParameterModifier (i) == Parameter.Modifier.PARAMS)
 213                                                 params_idx = i;
 214                                 }
 215                                 int n = invoke_pd.Count - (params_idx != -1 ? 1 : 0);
 216                                 Parameter [] fixedpars = new Parameter [n];
 217
 218                                 for (i =  j = 0; i < invoke_pd.Count; i++){
 219                                         if (invoke_pd.ParameterModifier (i) == Parameter.Modifier.PARAMS)
 220                                                 continue;
 221                                         fixedpars [j] = new Parameter (
 222                                                 new TypeExpression (invoke_pd.ParameterType (i), loc),
 223                                                 "+" + j, invoke_pd.ParameterModifier (i), null, loc);
 224                                         j++;
 225                                 }
 226
 227                                 Parameter variable = null;
 228                                 if (params_idx != -1){
 229                                         variable = new Parameter (
 230                                                 new TypeExpression (invoke_pd.ParameterType (params_idx), loc),
 231                                                 "+" + params_idx, invoke_pd.ParameterModifier (params_idx), null, loc);
 232                                 }
 233
 234                                 Parameters = new Parameters (fixedpars, variable);
 235                         }
 236
 237                         //
 238                         // First, parameter types of `delegate_type' must be compatible
 239                         // with the anonymous method.
 240                         //
 241                         amp = new InternalParameters (Parameters.GetParameterInfo (ec), Parameters);
 242
 243                         if (amp.Count != invoke_pd.Count){
 244                                 if (!probe){
 245                                         Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
 246                                                 TypeManager.CSharpName (delegate_type), amp.Count.ToString ());
 247                                         Error_ParameterMismatch (delegate_type);
 248                                 }
 249                                 return null;
 250                         }
 251
 252                         for (int i = 0; i < amp.Count; i++){
 253                                 Parameter.Modifier amp_mod = amp.ParameterModifier (i);
 254
 255                                 if (!probe) {
 256                                         if ((amp_mod & (Parameter.Modifier.OUT | Parameter.Modifier.REF)) != 0){
 257                                                 Report.Error (1677, loc, "Parameter `{0}' should not be declared with the `{1}' keyword",
 258                                                         (i+1).ToString (), amp.ModifierDesc (i));
 259                                                 Error_ParameterMismatch (delegate_type);
 260                                                 return null;
 261                                         }
 262
 263                                         if (amp_mod != invoke_pd.ParameterModifier (i)){
 264                                                 Report.Error (1676, loc, "Parameter `{0}' must be declared with the `{1}' keyword",
 265                                                         (i+1).ToString (), Parameter.GetModifierSignature (invoke_pd.ParameterModifier (i)));
 266                                                 Error_ParameterMismatch (delegate_type);
 267                                                 return null;
 268                                         }
 269
 270                                         if (amp.ParameterType (i) != invoke_pd.ParameterType (i)){
 271                                                 Report.Error (1678, loc, "Parameter `{0}' is declared as type `{1}' but should be `{2}'",
 272                                                         (i+1).ToString (),
 273                                                         TypeManager.CSharpName (amp.ParameterType (i)),
 274                                                         TypeManager.CSharpName (invoke_pd.ParameterType (i)));
 275                                                 Error_ParameterMismatch (delegate_type);
 276                                                 return null;
 277                                         }
 278                                 }
 279                         }
 280
 281                         //
 282                         // If we are only probing, return ourselves
 283                         //
 284                         if (probe)
 285                                 return this;
 286
 287                         //
 288                         // Second: the return type of the delegate must be compatible with
 289                         // the anonymous type.   Instead of doing a pass to examine the block
 290                         // we satisfy the rule by setting the return type on the EmitContext
 291                         // to be the delegate type return type.
 292                         //
 293
 294                         //MethodBuilder builder = method_data.MethodBuilder;
 295                         //ILGenerator ig = builder.GetILGenerator ();
 296
 297
 298                         aec = new EmitContext (
 299                                 ec.TypeContainer, ec.DeclSpace, loc, null,
 300                                 invoke_mb.ReturnType,
 301                                 /* REVIEW */ (ec.InIterator ? Modifiers.METHOD_YIELDS : 0) |
 302                                 (ec.InUnsafe ? Modifiers.UNSAFE : 0) |
 303                                 (ec.IsStatic ? Modifiers.STATIC : 0),
 304                                 /* No constructor */ false);
 305
 306                         aec.CurrentAnonymousMethod = this;
 307                         ContainerAnonymousMethod = ec.CurrentAnonymousMethod;
 308                         ContainingBlock = ec.CurrentBlock;
 309
 310                         if (aec.ResolveTopBlock (ec, Block, amp, null, out unreachable))
 311                                 return new AnonymousDelegate (this, delegate_type, loc).Resolve (ec);
 312
 313                         return null;
 314                 }
 315
 316                 public override string ExprClassName {
 317                         get {
 318                                 return "anonymous method";
 319                         }
 320                 }
 321
 322                 public MethodBuilder GetMethodBuilder ()
 323                 {
 324                         return method.MethodData.MethodBuilder;
 325                 }
 326
 327                 public override string GetSignatureForError ()
 328                 {
 329                         string s = TypeManager.CSharpSignature (invoke_mb);
 330                         return s.Substring (0, s.IndexOf (".Invoke("));
 331                 }
 332
 333                 public bool EmitMethod (EmitContext ec)
 334                 {
 335                         if (!CreateMethodHost (ec))
 336                                 return false;
 337
 338                         MethodBuilder builder = GetMethodBuilder ();
 339                         ILGenerator ig = builder.GetILGenerator ();
 340                         aec.ig = ig;
 341
 342                         Parameters.LabelParameters (aec, builder);
 343
 344                         //
 345                         // Adjust based on the computed state of the
 346                         // method from CreateMethodHost
 347
 348                         aec.MethodIsStatic = (method_modifiers & Modifiers.STATIC) != 0;
 349
 350                         aec.EmitMeta (Block, amp);
 351                         aec.EmitResolvedTopBlock (Block, unreachable);
 352                         return true;
 353                 }
 354
 355                 public override void CreateScopeType (EmitContext ec, ScopeInfo scope)
 356                 {
 357                         TypeBuilder container = ec.TypeContainer.TypeBuilder;
 358                         string name = String.Format ("<>AnonHelp<{0}>", scope.id);
 359
 360                         scope.ScopeTypeBuilder = container.DefineNestedType (
 361                                 name, TypeAttributes.AutoLayout | TypeAttributes.Class |
 362                                 TypeAttributes.NestedAssembly, TypeManager.object_type, null);
 363
 364                         Type [] constructor_types = TypeManager.NoTypes;
 365                         Parameters constructor_parameters = Parameters.EmptyReadOnlyParameters;
 366                         scope.ScopeConstructor = scope.ScopeTypeBuilder.DefineConstructor (
 367                                 MethodAttributes.Public | MethodAttributes.HideBySig |
 368                                 MethodAttributes.SpecialName | MethodAttributes.RTSpecialName,
 369                                 CallingConventions.HasThis, constructor_types);
 370                         InternalParameters parameter_info = new InternalParameters (constructor_types, constructor_parameters);
 371                         TypeManager.RegisterMethod (scope.ScopeConstructor, parameter_info, constructor_types);
 372
 373                         ILGenerator cig = scope.ScopeConstructor.GetILGenerator ();
 374                         cig.Emit (OpCodes.Ldarg_0);
 375                         cig.Emit (OpCodes.Call, TypeManager.object_ctor);
 376                         cig.Emit (OpCodes.Ret);
 377                 }
 378
 379                 public static void Error_AddressOfCapturedVar (string name, Location loc)
 380                 {
 381                         Report.Error (1686, loc,
 382                                 "Local variable `{0}' or its members cannot have their address taken and be used inside an anonymous method block",
 383                                 name);
 384                 }
 385         }
 386
 387         //
 388         // This will emit the code for the delegate, as well delegate creation on the host
 389         //
 390         public class AnonymousDelegate : DelegateCreation {
 391                 AnonymousMethod am;
 392
 393                 public AnonymousDelegate (AnonymousMethod am, Type target_type, Location l)
 394                 {
 395                         type = target_type;
 396                         loc = l;
 397                         this.am = am;
 398                 }
 399
 400                 public override Expression DoResolve (EmitContext ec)
 401                 {
 402                         eclass = ExprClass.Value;
 403
 404                         return this;
 405                 }
 406
 407                 public override void Emit (EmitContext ec)
 408                 {
 409                         if (!am.EmitMethod (ec))
 410                                 return;
 411
 412                         //
 413                         // Now emit the delegate creation.
 414                         //
 415                         if ((am.method.ModFlags & Modifiers.STATIC) == 0)
 416                                 delegate_instance_expression = new AnonymousInstance (am);
 417
 418                         Expression ml = Expression.MemberLookup (ec, type, ".ctor", loc);
 419                         constructor_method = ((MethodGroupExpr) ml).Methods [0];
 420                         delegate_method = am.GetMethodBuilder ();
 421                         base.Emit (ec);
 422                 }
 423
 424                 class AnonymousInstance : Expression {
 425                         AnonymousMethod am;
 426
 427                         public AnonymousInstance (AnonymousMethod am)
 428                         {
 429                                 this.am = am;
 430                                 eclass = ExprClass.Value;
 431                         }
 432
 433                         public override Expression DoResolve (EmitContext ec)
 434                         {
 435                                 return this;
 436                         }
 437
 438                         public override void Emit (EmitContext ec)
 439                         {
 440                                 am.aec.EmitMethodHostInstance (ec, am);
 441                         }
 442                 }
 443         }
 444
 445         class CapturedParameter {
 446                 public Type Type;
 447                 public FieldBuilder FieldBuilder;
 448                 public int Idx;
 449
 450                 public CapturedParameter (Type type, int idx)
 451                 {
 452                         Type = type;
 453                         Idx = idx;
 454                 }
 455         }
 456
 457         //
 458         // Here we cluster all the variables captured on a given scope, we also
 459         // keep some extra information that might be required on each scope.
 460         //
 461         public class ScopeInfo {
 462                 public CaptureContext CaptureContext;
 463                 public ScopeInfo ParentScope;
 464                 public Block ScopeBlock;
 465                 public bool NeedThis = false;
 466                 public bool HostsParameters = false;
 467
 468                 // For tracking the number of scopes created.
 469                 public int id;
 470                 static int count;
 471                 bool inited = false;
 472
 473                 ArrayList locals = new ArrayList ();
 474                 ArrayList children = new ArrayList ();
 475
 476                 //
 477                 // The types and fields generated
 478                 //
 479                 public TypeBuilder ScopeTypeBuilder;
 480                 public ConstructorBuilder ScopeConstructor;
 481                 public FieldBuilder THIS;
 482                 public FieldBuilder ParentLink;
 483
 484                 //
 485                 // Points to the object of type `ScopeTypeBuilder' that
 486                 // holds the data for the scope
 487                 //
 488                 LocalBuilder scope_instance;
 489
 490                 public ScopeInfo (CaptureContext cc, Block b)
 491                 {
 492                         CaptureContext = cc;
 493                         ScopeBlock = b;
 494                         id = count++;
 495
 496                         cc.AddScope (this);
 497                 }
 498
 499                 public void AddLocal (LocalInfo li)
 500                 {
 501                         if (locals.Contains (li))
 502                                 return;
 503
 504                         locals.Add (li);
 505                 }
 506
 507                 public bool IsCaptured (LocalInfo li)
 508                 {
 509                         return locals.Contains (li);
 510                 }
 511
 512                 internal void AddChild (ScopeInfo si)
 513                 {
 514                         if (children.Contains (si))
 515                                 return;
 516
 517                         //
 518                         // If any of the current children should be a children of `si', move them there
 519                         //
 520                         ArrayList move_queue = null;
 521                         foreach (ScopeInfo child in children){
 522                                 if (child.ScopeBlock.IsChildOf (si.ScopeBlock)){
 523                                         if (move_queue == null)
 524                                                 move_queue = new ArrayList ();
 525                                         move_queue.Add (child);
 526                                         child.ParentScope = si;
 527                                         si.AddChild (child);
 528                                 }
 529                         }
 530
 531                         children.Add (si);
 532
 533                         if (move_queue != null){
 534                                 foreach (ScopeInfo child in move_queue){
 535                                         children.Remove (child);
 536                                 }
 537                         }
 538                 }
 539
 540                 static int indent = 0;
 541
 542                 void Pad ()
 543                 {
 544                         for (int i = 0; i < indent; i++)
 545                                 Console.Write ("    ");
 546                 }
 547
 548                 void EmitDebug ()
 549                 {
 550                         //Console.WriteLine (Environment.StackTrace);
 551                         Pad ();
 552                         Console.WriteLine ("START");
 553                         indent++;
 554                         Pad ();
 555                         Console.WriteLine ("NeedThis=" + NeedThis);
 556                         foreach (LocalInfo li in locals){
 557                                 Pad ();
 558                                 Console.WriteLine ("var {0}", MakeFieldName (li.Name));
 559                         }
 560
 561                         foreach (ScopeInfo si in children)
 562                                 si.EmitDebug ();
 563                         indent--;
 564                         Pad ();
 565                         Console.WriteLine ("END");
 566                 }
 567
 568                 public string MakeHelperName ()
 569                 {
 570                         return String.Format ("<>AnonHelp<{0}>", id);
 571                 }
 572
 573                 private string MakeFieldName (string local_name)
 574                 {
 575                         return "<" + id + ":" + local_name + ">";
 576                 }
 577
 578                 public void EmitScopeType (EmitContext ec)
 579                 {
 580                         // EmitDebug ();
 581
 582                         if (ScopeTypeBuilder != null)
 583                                 return;
 584
 585                         TypeBuilder container = ec.TypeContainer.TypeBuilder;
 586
 587                         CaptureContext.Host.CreateScopeType (ec, this);
 588
 589                         if (NeedThis)
 590                                 THIS = ScopeTypeBuilder.DefineField ("<>THIS", container, FieldAttributes.Assembly);
 591
 592                         if (ParentScope != null){
 593                                 if (ParentScope.ScopeTypeBuilder == null){
 594                                         throw new Exception (String.Format ("My parent has not been initialized {0} and {1}", ParentScope, this));
 595                                 }
 596
 597                                 if (ParentScope.ScopeTypeBuilder != ScopeTypeBuilder)
 598                                         ParentLink = ScopeTypeBuilder.DefineField ("<>parent", ParentScope.ScopeTypeBuilder,
 599                                                                                    FieldAttributes.Assembly);
 600                         }
 601
 602                         if (NeedThis && ParentScope != null)
 603                                 throw new Exception ("I was not expecting THIS && having a parent");
 604
 605                         foreach (LocalInfo info in locals)
 606                                 info.FieldBuilder = ScopeTypeBuilder.DefineField (
 607                                         MakeFieldName (info.Name), info.VariableType, FieldAttributes.Assembly);
 608
 609                         if (HostsParameters){
 610                                 Hashtable captured_parameters = CaptureContext.captured_parameters;
 611
 612                                 foreach (DictionaryEntry de in captured_parameters){
 613                                         string name = (string) de.Key;
 614                                         CapturedParameter cp = (CapturedParameter) de.Value;
 615                                         FieldBuilder fb;
 616
 617                                         fb = ScopeTypeBuilder.DefineField ("<p:" + name + ">", cp.Type, FieldAttributes.Assembly);
 618                                         cp.FieldBuilder = fb;
 619                                 }
 620                         }
 621
 622                         foreach (ScopeInfo si in children){
 623                                 si.EmitScopeType (ec);
 624                         }
 625                 }
 626
 627                 public void CloseTypes ()
 628                 {
 629                         RootContext.RegisterCompilerGeneratedType (ScopeTypeBuilder);
 630                         foreach (ScopeInfo si in children)
 631                                 si.CloseTypes ();
 632                 }
 633
 634                 //
 635                 // Emits the initialization code for the scope
 636                 //
 637                 public void EmitInitScope (EmitContext ec)
 638                 {
 639                         ILGenerator ig = ec.ig;
 640
 641                         if (inited)
 642                                 return;
 643
 644                         if (ScopeConstructor == null)
 645                                 throw new Exception ("ScopeConstructor is null for" + this.ToString ());
 646
 647                         if (!CaptureContext.Host.IsIterator) {
 648                                 scope_instance = ig.DeclareLocal (ScopeTypeBuilder);
 649                                 ig.Emit (OpCodes.Newobj, (ConstructorInfo) ScopeConstructor);
 650                                 ig.Emit (OpCodes.Stloc, scope_instance);
 651                         }
 652
 653                         if (THIS != null){
 654                                 if (CaptureContext.Host.IsIterator) {
 655                                         ig.Emit (OpCodes.Ldarg_0);
 656                                         ig.Emit (OpCodes.Ldarg_1);
 657                                 } else {
 658                                         ig.Emit (OpCodes.Ldloc, scope_instance);
 659                                         ig.Emit (OpCodes.Ldarg_0);
 660                                 }
 661                                 ig.Emit (OpCodes.Stfld, THIS);
 662                         }
 663
 664                         //
 665                         // Copy the parameter values, if any
 666                         //
 667                         int extra = ec.IsStatic ? 0 : 1;
 668                         if (CaptureContext.Host.IsIterator)
 669                                 extra++;
 670                         if (HostsParameters){
 671                                 Hashtable captured_parameters = CaptureContext.captured_parameters;
 672
 673                                 foreach (DictionaryEntry de in captured_parameters){
 674                                         CapturedParameter cp = (CapturedParameter) de.Value;
 675
 676                                         EmitScopeInstance (ig);
 677                                         ParameterReference.EmitLdArg (ig, cp.Idx + extra);
 678                                         ig.Emit (OpCodes.Stfld, cp.FieldBuilder);
 679                                 }
 680                         }
 681
 682                         if (ParentScope != null){
 683                                 if (!ParentScope.inited)
 684                                         ParentScope.EmitInitScope (ec);
 685
 686                                 if (ParentScope.ScopeTypeBuilder != ScopeTypeBuilder) {
 687                                         //
 688                                         // Only emit initialization in our capturecontext world
 689                                         //
 690                                         if (ParentScope.CaptureContext == CaptureContext){
 691                                                 EmitScopeInstance (ig);
 692                                                 ParentScope.EmitScopeInstance (ig);
 693                                                 ig.Emit (OpCodes.Stfld, ParentLink);
 694                                         } else {
 695                                                 EmitScopeInstance (ig);
 696                                                 ig.Emit (OpCodes.Ldarg_0);
 697                                                 ig.Emit (OpCodes.Stfld, ParentLink);
 698                                         }
 699                                 }
 700                         }
 701                         inited = true;
 702                 }
 703
 704                 public void EmitScopeInstance (ILGenerator ig)
 705                 {
 706                         if (CaptureContext.Host.IsIterator)
 707                                 ig.Emit (OpCodes.Ldarg_0);
 708                         else
 709                                 ig.Emit (OpCodes.Ldloc, scope_instance);
 710                 }
 711
 712                 static void DoPath (StringBuilder sb, ScopeInfo start)
 713                 {
 714                         if (start.ParentScope != null){
 715                                 DoPath (sb, start.ParentScope);
 716                                 sb.Append (", ");
 717                         }
 718                         sb.Append ((start.id).ToString ());
 719                 }
 720
 721                 public override string ToString ()
 722                 {
 723                         StringBuilder sb = new StringBuilder ();
 724
 725                         sb.Append ("{");
 726                         if (CaptureContext != null){
 727                                 sb.Append (CaptureContext.ToString ());
 728                                 sb.Append (":");
 729                         }
 730
 731                         DoPath (sb, this);
 732                         sb.Append ("}");
 733
 734                         return sb.ToString ();
 735                 }
 736         }
 737
 738         //
 739         // CaptureContext objects are created on demand if a method has
 740         // anonymous methods and kept on the ToplevelBlock.
 741         //
 742         // If they exist, all ToplevelBlocks in the containing block are
 743         // linked together (children pointing to their parents).
 744         //
 745         public class CaptureContext {
 746                 public static int count;
 747                 public int cc_id;
 748                 public Location loc;
 749
 750                 //
 751                 // Points to the toplevel block that owns this CaptureContext
 752                 //
 753                 ToplevelBlock toplevel_owner;
 754                 Hashtable scopes = new Hashtable ();
 755                 bool have_captured_vars = false;
 756                 bool referenced_this = false;
 757                 ScopeInfo topmost = null;
 758
 759                 //
 760                 // Captured fields
 761                 //
 762                 Hashtable captured_fields = new Hashtable ();
 763                 Hashtable captured_variables = new Hashtable ();
 764                 public Hashtable captured_parameters = new Hashtable ();
 765                 public AnonymousContainer Host;
 766
 767                 public CaptureContext (ToplevelBlock toplevel_owner, Location loc,
 768                                        AnonymousContainer host)
 769                 {
 770                         cc_id = count++;
 771                         this.toplevel_owner = toplevel_owner;
 772                         this.loc = loc;
 773
 774                         if (host != null)
 775                                 Host = host;
 776                 }
 777
 778                 void DoPath (StringBuilder sb, CaptureContext cc)
 779                 {
 780                         if (cc.ParentCaptureContext != null){
 781                                 DoPath (sb, cc.ParentCaptureContext);
 782                                 sb.Append (".");
 783                         }
 784                         sb.Append (cc.cc_id.ToString ());
 785                 }
 786
 787                 public void ReParent (ToplevelBlock new_toplevel, AnonymousContainer new_host)
 788                 {
 789                         toplevel_owner = new_toplevel;
 790                         Host = new_host;
 791
 792                         for (CaptureContext cc = ParentCaptureContext; cc != null;
 793                              cc = cc.ParentCaptureContext) {
 794                                 cc.Host = new_host;
 795                         }
 796                 }
 797
 798                 public override string ToString ()
 799                 {
 800                         StringBuilder sb = new StringBuilder ();
 801                         sb.Append ("[");
 802                         DoPath (sb, this);
 803                         sb.Append ("]");
 804                         return sb.ToString ();
 805                 }
 806
 807                 public ToplevelBlock ParentToplevel {
 808                         get {
 809                                 return toplevel_owner.Container;
 810                         }
 811                 }
 812
 813                 public CaptureContext ParentCaptureContext {
 814                         get {
 815                                 ToplevelBlock parent = ParentToplevel;
 816
 817                                 return (parent == null) ? null : parent.CaptureContext;
 818                         }
 819                 }
 820
 821                 // Returns the deepest of two scopes
 822                 public ScopeInfo Deepest (ScopeInfo a, ScopeInfo b)
 823                 {
 824                         ScopeInfo p;
 825
 826                         if (a == null)
 827                                 return b;
 828                         if (b == null)
 829                                 return a;
 830                         if (a == b)
 831                                 return a;
 832
 833                         //
 834                         // If they Scopes are on the same CaptureContext, we do the double
 835                         // checks just so if there is an invariant change in the future,
 836                         // we get the exception at the end
 837                         //
 838                         for (p = a; p != null; p = p.ParentScope)
 839                                 if (p == b)
 840                                         return a;
 841
 842                         for (p = b; p != null; p = p.ParentScope)
 843                                 if (p == a)
 844                                         return b;
 845
 846                         CaptureContext ca = a.CaptureContext;
 847                         CaptureContext cb = b.CaptureContext;
 848
 849                         for (CaptureContext c = ca; c != null; c = c.ParentCaptureContext)
 850                                 if (c == cb)
 851                                         return a;
 852
 853                         for (CaptureContext c = cb; c != null; c = c.ParentCaptureContext)
 854                                 if (c == ca)
 855                                         return b;
 856                         throw new Exception ("Should never be reached");
 857                 }
 858
 859                 void AdjustMethodScope (AnonymousContainer am, ScopeInfo scope)
 860                 {
 861                         am.Scope = Deepest (am.Scope, scope);
 862                 }
 863
 864                 void LinkScope (ScopeInfo scope, int id)
 865                 {
 866                         ScopeInfo parent = (ScopeInfo) scopes [id];
 867                         scope.ParentScope = parent;
 868                         parent.AddChild (scope);
 869
 870                         if (scope == topmost)
 871                                 topmost = parent;
 872                 }
 873
 874                 public void AddLocal (AnonymousContainer am, LocalInfo li)
 875                 {
 876                         if (li.Block.Toplevel != toplevel_owner){
 877                                 ParentCaptureContext.AddLocal (am, li);
 878                                 return;
 879                         }
 880                         int block_id = li.Block.ID;
 881                         ScopeInfo scope;
 882                         if (scopes [block_id] == null){
 883                                 scope = new ScopeInfo (this, li.Block);
 884                                 scopes [block_id] = scope;
 885                         } else
 886                                 scope = (ScopeInfo) scopes [block_id];
 887
 888                         if (topmost == null){
 889                                 topmost = scope;
 890                         } else {
 891                                 // Link to parent
 892
 893                                 for (Block b = scope.ScopeBlock.Parent; b != null; b = b.Parent){
 894                                         if (scopes [b.ID] != null){
 895                                                 LinkScope (scope, b.ID);
 896                                                 break;
 897                                         }
 898                                 }
 899
 900                                 if (scope.ParentScope == null && ParentCaptureContext != null){
 901                                         CaptureContext pcc = ParentCaptureContext;
 902
 903                                         for (Block b = am.ContainingBlock; b != null; b = b.Parent){
 904                                                 if (pcc.scopes [b.ID] != null){
 905                                                         pcc.LinkScope (scope, b.ID);
 906                                                         break;
 907                                                 }
 908                                         }
 909                                 }
 910                         }
 911
 912                         //
 913                         // Adjust the owner
 914                         //
 915                         if (Host != null)
 916                                 AdjustMethodScope (Host, topmost);
 917
 918                         //
 919                         // Adjust the user
 920                         //
 921                         AdjustMethodScope (am, scope);
 922
 923                         if (captured_variables [li] != null)
 924                                 return;
 925
 926                         have_captured_vars = true;
 927                         captured_variables [li] = li;
 928                         scope.AddLocal (li);
 929                 }
 930
 931                 //
 932                 // Retursn the CaptureContext for the block that defines the parameter `name'
 933                 //
 934                 static CaptureContext _ContextForParameter (ToplevelBlock current, string name)
 935                 {
 936                         ToplevelBlock container = current.Container;
 937                         if (container != null){
 938                                 CaptureContext cc = _ContextForParameter (container, name);
 939                                 if (cc != null)
 940                                         return cc;
 941                         }
 942                         if (current.IsParameterReference (name))
 943                                 return current.ToplevelBlockCaptureContext;
 944                         return null;
 945                 }
 946
 947                 static CaptureContext ContextForParameter (ToplevelBlock current, string name)
 948                 {
 949                         CaptureContext cc = _ContextForParameter (current, name);
 950                         if (cc == null)
 951                                 throw new Exception (String.Format ("request for parameteter {0} failed: not found", name));
 952                         return cc;
 953                 }
 954
 955                 //
 956                 // Records the captured parameter at the appropriate CaptureContext
 957                 //
 958                 public void AddParameter (EmitContext ec, AnonymousContainer am,
 959                                           string name, Type t, int idx)
 960                 {
 961                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
 962
 963                         cc.AddParameterToContext (am, name, t, idx);
 964                 }
 965
 966                 //
 967                 // Records the parameters in the context
 968                 //
 969                 public void AddParameterToContext (AnonymousContainer am, string name, Type t, int idx)
 970                 {
 971                         if (captured_parameters == null)
 972                                 captured_parameters = new Hashtable ();
 973                         if (captured_parameters [name] == null)
 974                                 captured_parameters [name] = new CapturedParameter (t, idx);
 975
 976                         if (topmost == null){
 977                                 //
 978                                 // Create one ScopeInfo, if there are none.
 979                                 //
 980                                 topmost = new ScopeInfo (this, toplevel_owner);
 981                                 scopes [toplevel_owner.ID] = topmost;
 982                         } else {
 983                                 //
 984                                 // If the topmost ScopeInfo is not at the topblock level, insert
 985                                 // a new ScopeInfo there.
 986                                 //
 987                                 // FIXME: This code probably should be evolved to be like the code
 988                                 // in AddLocal
 989                                 //
 990                                 if (topmost.ScopeBlock != toplevel_owner){
 991                                         ScopeInfo par_si = new ScopeInfo (this, toplevel_owner);
 992                                         ScopeInfo old_top = topmost;
 993                                         scopes [toplevel_owner.ID] = topmost;
 994                                         topmost.ParentScope = par_si;
 995                                         topmost = par_si;
 996                                         topmost.AddChild (old_top);
 997                                 }
 998                         }
 999
1000                         topmost.HostsParameters = true;
1001                         AdjustMethodScope (am, topmost);
1002                 }
1003
1004                 //
1005                 // Captured fields are only recorded on the topmost CaptureContext, because that
1006                 // one is the one linked to the owner of instance fields
1007                 //
1008                 public void AddField (EmitContext ec, AnonymousContainer am, FieldExpr fe)
1009                 {
1010                         if (fe.FieldInfo.IsStatic)
1011                                 throw new Exception ("Attempt to register a static field as a captured field");
1012                         CaptureContext parent = ParentCaptureContext;
1013                         if (parent != null) {
1014                                 parent.AddField (ec, am, fe);
1015                                 return;
1016                         }
1017
1018                         if (topmost == null){
1019                                 //
1020                                 // Create one ScopeInfo, if there are none.
1021                                 //
1022                                 topmost = new ScopeInfo (this, toplevel_owner);
1023                                 scopes [toplevel_owner.ID] = topmost;
1024                         }
1025
1026                         AdjustMethodScope (am, topmost);
1027                 }
1028
1029                 public void CaptureThis ()
1030                 {
1031                         CaptureContext parent = ParentCaptureContext;
1032                         if (parent != null)
1033                                 parent.CaptureThis ();
1034                         referenced_this = true;
1035                 }
1036
1037                 public bool HaveCapturedVariables {
1038                         get {
1039                                 return have_captured_vars;
1040                         }
1041                 }
1042
1043                 public bool HaveCapturedFields {
1044                         get {
1045                                 CaptureContext parent = ParentCaptureContext;
1046                                 if (parent != null)
1047                                         return parent.HaveCapturedFields;
1048                                 return captured_fields.Count > 0;
1049                         }
1050                 }
1051
1052                 public bool IsCaptured (LocalInfo local)
1053                 {
1054                         foreach (ScopeInfo si in scopes.Values){
1055                                 if (si.IsCaptured (local))
1056                                         return true;
1057                         }
1058                         return false;
1059                 }
1060
1061                 //
1062                 // Returns whether the parameter is captured
1063                 //
1064                 public bool IsParameterCaptured (string name)
1065                 {
1066                         if (ParentCaptureContext != null && ParentCaptureContext.IsParameterCaptured (name))
1067                                 return true;
1068
1069                         if (captured_parameters != null)
1070                                 return captured_parameters [name] != null;
1071                         return false;
1072                 }
1073
1074                 public void EmitAnonymousHelperClasses (EmitContext ec)
1075                 {
1076                         if (topmost != null){
1077                                 topmost.NeedThis = HaveCapturedFields || referenced_this;
1078                                 topmost.EmitScopeType (ec);
1079                         }
1080                 }
1081
1082                 public void CloseAnonymousHelperClasses ()
1083                 {
1084                         if (topmost != null)
1085                                 topmost.CloseTypes ();
1086                 }
1087
1088                 public void EmitInitScope (EmitContext ec)
1089                 {
1090                         EmitAnonymousHelperClasses (ec);
1091                         if (topmost != null)
1092                                 topmost.EmitInitScope (ec);
1093                 }
1094
1095                 ScopeInfo GetScopeFromBlock (EmitContext ec, Block b)
1096                 {
1097                         ScopeInfo si;
1098
1099                         si = (ScopeInfo) scopes [b.ID];
1100                         if (si == null)
1101                                 throw new Exception ("Si is null for block " + b.ID);
1102                         si.EmitInitScope (ec);
1103
1104                         return si;
1105                 }
1106
1107                 //
1108                 // Emits the opcodes necessary to load the instance of the captured
1109                 // variable in `li'
1110                 //
1111                 public void EmitCapturedVariableInstance (EmitContext ec, LocalInfo li,
1112                                                           AnonymousContainer am)
1113                 {
1114                         ILGenerator ig = ec.ig;
1115                         ScopeInfo si;
1116
1117                         if (li.Block.Toplevel == toplevel_owner){
1118                                 si = GetScopeFromBlock (ec, li.Block);
1119                                 si.EmitScopeInstance (ig);
1120                                 return;
1121                         }
1122
1123                         si = am.Scope;
1124                         ig.Emit (OpCodes.Ldarg_0);
1125                         if (si != null){
1126                                 if (am.IsIterator && (si.ScopeBlock.Toplevel == li.Block.Toplevel)) {
1127                                         return;
1128                                 }
1129
1130                                 while (si.ScopeBlock.ID != li.Block.ID){
1131                                         if (si.ParentLink != null)
1132                                                 ig.Emit (OpCodes.Ldfld, si.ParentLink);
1133                                         si = si.ParentScope;
1134                                         if (si == null) {
1135                                                 si = am.Scope;
1136                                                 Console.WriteLine ("Target: {0} {1}", li.Block.ID, li.Name);
1137                                                 while (si.ScopeBlock.ID != li.Block.ID){
1138                                                         Console.WriteLine ("Trying: {0}", si.ScopeBlock.ID);
1139                                                         si = si.ParentScope;
1140                                                 }
1141
1142                                                 throw new Exception (
1143                                                              String.Format ("Never found block {0} starting at {1} while looking up {2}",
1144                                                                             li.Block.ID, am.Scope.ScopeBlock.ID, li.Name));
1145                                         }
1146                                 }
1147                         }
1148                 }
1149
1150                 //
1151                 // Internal routine that loads the instance to reach parameter `name'
1152                 //
1153                 void EmitParameterInstance (EmitContext ec, string name)
1154                 {
1155                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
1156                         if (cc != this){
1157                                 cc.EmitParameterInstance (ec, name);
1158                                 return;
1159                         }
1160
1161                         CapturedParameter par_info = (CapturedParameter) captured_parameters [name];
1162                         if (par_info != null){
1163                                 //
1164                                 // FIXME: implementing this.
1165                                 //
1166                         }
1167                         ILGenerator ig = ec.ig;
1168
1169                         ScopeInfo si;
1170
1171                         if (ec.CurrentBlock.Toplevel == toplevel_owner) {
1172                                 si = GetScopeFromBlock (ec, toplevel_owner);
1173                                 si.EmitScopeInstance (ig);
1174                         } else {
1175                                 si = ec.CurrentAnonymousMethod.Scope;
1176                                 ig.Emit (OpCodes.Ldarg_0);
1177                         }
1178
1179                         if (si != null){
1180                                 while (si.ParentLink != null) {
1181                                         ig.Emit (OpCodes.Ldfld, si.ParentLink);
1182                                         si = si.ParentScope;
1183                                 }
1184                         }
1185                 }
1186
1187                 //
1188                 // Emits the code necessary to load the parameter named `name' within
1189                 // an anonymous method.
1190                 //
1191                 public void EmitParameter (EmitContext ec, string name)
1192                 {
1193                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
1194                         if (cc != this){
1195                                 cc.EmitParameter (ec, name);
1196                                 return;
1197                         }
1198                         EmitParameterInstance (ec, name);
1199                         CapturedParameter par_info = (CapturedParameter) captured_parameters [name];
1200                         if (par_info != null){
1201                                 //
1202                                 // FIXME: implementing this.
1203                                 //
1204                         }
1205                         ec.ig.Emit (OpCodes.Ldfld, par_info.FieldBuilder);
1206                 }
1207
1208                 //
1209                 // Implements the assignment of `source' to the paramenter named `name' within
1210                 // an anonymous method.
1211                 //
1212                 public void EmitAssignParameter (EmitContext ec, string name, Expression source, bool leave_copy, bool prepare_for_load)
1213                 {
1214                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
1215                         if (cc != this){
1216                                 cc.EmitAssignParameter (ec, name, source, leave_copy, prepare_for_load);
1217                                 return;
1218                         }
1219                         ILGenerator ig = ec.ig;
1220                         CapturedParameter par_info = (CapturedParameter) captured_parameters [name];
1221
1222                         EmitParameterInstance (ec, name);
1223                         if (leave_copy)
1224                                 ig.Emit (OpCodes.Dup);
1225                         source.Emit (ec);
1226                         ig.Emit (OpCodes.Stfld, par_info.FieldBuilder);
1227                         if (leave_copy){
1228                                 ig.Emit (OpCodes.Ldfld, par_info.FieldBuilder);
1229                         }
1230                 }
1231
1232                 //
1233                 // Emits the address for the parameter named `name' within
1234                 // an anonymous method.
1235                 //
1236                 public void EmitAddressOfParameter (EmitContext ec, string name)
1237                 {
1238                         CaptureContext cc = ContextForParameter (ec.CurrentBlock.Toplevel, name);
1239                         if (cc != this){
1240                                 cc.EmitAddressOfParameter (ec, name);
1241                                 return;
1242                         }
1243                         EmitParameterInstance (ec, name);
1244                         CapturedParameter par_info = (CapturedParameter) captured_parameters [name];
1245                         ec.ig.Emit (OpCodes.Ldflda, par_info.FieldBuilder);
1246                 }
1247
1248                 //
1249                 // The following methods are only invoked on the host for the
1250                 // anonymous method.
1251                 //
1252                 public void EmitMethodHostInstance (EmitContext target, AnonymousContainer am)
1253                 {
1254                         ILGenerator ig = target.ig;
1255                         ScopeInfo si = am.Scope;
1256
1257                         if (si == null){
1258                                 ig.Emit (OpCodes.Ldarg_0);
1259                                 return;
1260                         }
1261
1262                         si.EmitInitScope (target);
1263                         si.EmitScopeInstance (ig);
1264                 }
1265
1266                 ArrayList all_scopes = new ArrayList ();
1267
1268                 public void AddScope (ScopeInfo si)
1269                 {
1270                         all_scopes.Add (si);
1271                         toplevel_owner.RegisterCaptureContext (this);
1272                 }
1273
1274                 //
1275                 // Links any scopes that were not linked previously
1276                 //
1277                 public void AdjustScopes ()
1278                 {
1279                         foreach (ScopeInfo scope in all_scopes){
1280                                 if (scope.ParentScope != null)
1281                                         continue;
1282
1283                                 for (Block b = scope.ScopeBlock.Parent; b != null; b = b.Parent){
1284                                         if (scopes [b.ID] != null){
1285                                                 LinkScope (scope, b.ID);
1286                                                 break;
1287                                         }
1288                                 }
1289
1290                                 if (scope.ParentScope == null && ParentCaptureContext != null){
1291                                         CaptureContext pcc = ParentCaptureContext;
1292
1293                                         for (Block b = Host.ContainingBlock; b != null; b = b.Parent){
1294                                                 if (pcc.scopes [b.ID] != null){
1295                                                         pcc.LinkScope (scope, b.ID);
1296                                                         break;
1297                                                 }
1298                                         }
1299                                 }
1300                         }
1301                 }
1302         }
1303 }