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