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2006-04-27 Jonathan Chambers <jonathan.chambers@ansys.com>
[mcs.git] / gmcs / statement.cs
blobdd105e4032efbb837269fd97c6e54d2f10624f20
1 //
2 // statement.cs: Statement representation for the IL tree.
3 //
4 // Author:
5 // Miguel de Icaza (miguel@ximian.com)
6 // Martin Baulig (martin@ximian.com)
7 //
8 // (C) 2001, 2002, 2003 Ximian, Inc.
9 // (C) 2003, 2004 Novell, Inc.
10 //
11
12 using System;
13 using System.Text;
14 using System.Reflection;
15 using System.Reflection.Emit;
16 using System.Diagnostics;
17 using System.Collections;
18 using System.Collections.Specialized;
19
20 namespace Mono.CSharp {
21
22 public abstract class Statement {
23 public Location loc;
24
25 /// <summary>
26 /// Resolves the statement, true means that all sub-statements
27 /// did resolve ok.
28 // </summary>
29 public virtual bool Resolve (EmitContext ec)
30 {
31 return true;
32 }
33
34 /// <summary>
35 /// We already know that the statement is unreachable, but we still
36 /// need to resolve it to catch errors.
37 /// </summary>
38 public virtual bool ResolveUnreachable (EmitContext ec, bool warn)
39 {
40 //
41 // This conflicts with csc's way of doing this, but IMHO it's
42 // the right thing to do.
43 //
44 // If something is unreachable, we still check whether it's
45 // correct. This means that you cannot use unassigned variables
46 // in unreachable code, for instance.
47 //
48
49 if (warn)
50 Report.Warning (162, 2, loc, "Unreachable code detected");
51
52 ec.StartFlowBranching (FlowBranching.BranchingType.Block, loc);
53 bool ok = Resolve (ec);
54 ec.KillFlowBranching ();
55
56 return ok;
57 }
58
59 /// <summary>
60 /// Return value indicates whether all code paths emitted return.
61 /// </summary>
62 protected abstract void DoEmit (EmitContext ec);
63
64 /// <summary>
65 /// Utility wrapper routine for Error, just to beautify the code
66 /// </summary>
67 public void Error (int error, string format, params object[] args)
68 {
69 Error (error, String.Format (format, args));
70 }
71
72 public void Error (int error, string s)
73 {
74 if (!loc.IsNull)
75 Report.Error (error, loc, s);
76 else
77 Report.Error (error, s);
78 }
79
80 /// <summary>
81 /// Return value indicates whether all code paths emitted return.
82 /// </summary>
83 public virtual void Emit (EmitContext ec)
84 {
85 ec.Mark (loc, true);
86 DoEmit (ec);
87 }
88 }
89
90 public sealed class EmptyStatement : Statement {
91
92 private EmptyStatement () {}
93
94 public static readonly EmptyStatement Value = new EmptyStatement ();
95
96 public override bool Resolve (EmitContext ec)
97 {
98 return true;
99 }
100
101 protected override void DoEmit (EmitContext ec)
102 {
103 }
104 }
105
106 public class If : Statement {
107 Expression expr;
108 public Statement TrueStatement;
109 public Statement FalseStatement;
110
111 bool is_true_ret;
112
113 public If (Expression expr, Statement trueStatement, Location l)
114 {
115 this.expr = expr;
116 TrueStatement = trueStatement;
117 loc = l;
118 }
119
120 public If (Expression expr,
121 Statement trueStatement,
122 Statement falseStatement,
123 Location l)
124 {
125 this.expr = expr;
126 TrueStatement = trueStatement;
127 FalseStatement = falseStatement;
128 loc = l;
129 }
130
131 public override bool Resolve (EmitContext ec)
132 {
133 bool ok = true;
134
135 Report.Debug (1, "START IF BLOCK", loc);
136
137 expr = Expression.ResolveBoolean (ec, expr, loc);
138 if (expr == null){
139 ok = false;
140 goto skip;
141 }
142
143 Assign ass = expr as Assign;
144 if (ass != null && ass.Source is Constant) {
145 Report.Warning (665, 3, loc, "Assignment in conditional expression is always constant; did you mean to use == instead of = ?");
146 }
147
148 //
149 // Dead code elimination
150 //
151 if (expr is BoolConstant){
152 bool take = ((BoolConstant) expr).Value;
153
154 if (take){
155 if (!TrueStatement.Resolve (ec))
156 return false;
157
158 if ((FalseStatement != null) &&
159 !FalseStatement.ResolveUnreachable (ec, true))
160 return false;
161 FalseStatement = null;
162 } else {
163 if (!TrueStatement.ResolveUnreachable (ec, true))
164 return false;
165 TrueStatement = null;
166
167 if ((FalseStatement != null) &&
168 !FalseStatement.Resolve (ec))
169 return false;
170 }
171
172 return true;
173 }
174 skip:
175 ec.StartFlowBranching (FlowBranching.BranchingType.Conditional, loc);
176
177 ok &= TrueStatement.Resolve (ec);
178
179 is_true_ret = ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable;
180
181 ec.CurrentBranching.CreateSibling ();
182
183 if (FalseStatement != null)
184 ok &= FalseStatement.Resolve (ec);
185
186 ec.EndFlowBranching ();
187
188 Report.Debug (1, "END IF BLOCK", loc);
189
190 return ok;
191 }
192
193 protected override void DoEmit (EmitContext ec)
194 {
195 ILGenerator ig = ec.ig;
196 Label false_target = ig.DefineLabel ();
197 Label end;
198
199 //
200 // If we're a boolean expression, Resolve() already
201 // eliminated dead code for us.
202 //
203 if (expr is BoolConstant){
204 bool take = ((BoolConstant) expr).Value;
205
206 if (take)
207 TrueStatement.Emit (ec);
208 else if (FalseStatement != null)
209 FalseStatement.Emit (ec);
210
211 return;
212 }
213
214 expr.EmitBranchable (ec, false_target, false);
215
216 TrueStatement.Emit (ec);
217
218 if (FalseStatement != null){
219 bool branch_emitted = false;
220
221 end = ig.DefineLabel ();
222 if (!is_true_ret){
223 ig.Emit (OpCodes.Br, end);
224 branch_emitted = true;
225 }
226
227 ig.MarkLabel (false_target);
228 FalseStatement.Emit (ec);
229
230 if (branch_emitted)
231 ig.MarkLabel (end);
232 } else {
233 ig.MarkLabel (false_target);
234 }
235 }
236 }
237
238 public class Do : Statement {
239 public Expression expr;
240 public readonly Statement EmbeddedStatement;
241 bool infinite;
242
243 public Do (Statement statement, Expression boolExpr, Location l)
244 {
245 expr = boolExpr;
246 EmbeddedStatement = statement;
247 loc = l;
248 }
249
250 public override bool Resolve (EmitContext ec)
251 {
252 bool ok = true;
253
254 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
255
256 if (!EmbeddedStatement.Resolve (ec))
257 ok = false;
258
259 expr = Expression.ResolveBoolean (ec, expr, loc);
260 if (expr == null)
261 ok = false;
262 else if (expr is BoolConstant){
263 bool res = ((BoolConstant) expr).Value;
264
265 if (res)
266 infinite = true;
267 }
268
269 ec.CurrentBranching.Infinite = infinite;
270 ec.EndFlowBranching ();
271
272 return ok;
273 }
274
275 protected override void DoEmit (EmitContext ec)
276 {
277 ILGenerator ig = ec.ig;
278 Label loop = ig.DefineLabel ();
279 Label old_begin = ec.LoopBegin;
280 Label old_end = ec.LoopEnd;
281
282 ec.LoopBegin = ig.DefineLabel ();
283 ec.LoopEnd = ig.DefineLabel ();
284
285 ig.MarkLabel (loop);
286 EmbeddedStatement.Emit (ec);
287 ig.MarkLabel (ec.LoopBegin);
288
289 //
290 // Dead code elimination
291 //
292 if (expr is BoolConstant){
293 bool res = ((BoolConstant) expr).Value;
294
295 if (res)
296 ec.ig.Emit (OpCodes.Br, loop);
297 } else
298 expr.EmitBranchable (ec, loop, true);
299
300 ig.MarkLabel (ec.LoopEnd);
301
302 ec.LoopBegin = old_begin;
303 ec.LoopEnd = old_end;
304 }
305 }
306
307 public class While : Statement {
308 public Expression expr;
309 public readonly Statement Statement;
310 bool infinite, empty;
311
312 public While (Expression boolExpr, Statement statement, Location l)
313 {
314 this.expr = boolExpr;
315 Statement = statement;
316 loc = l;
317 }
318
319 public override bool Resolve (EmitContext ec)
320 {
321 bool ok = true;
322
323 expr = Expression.ResolveBoolean (ec, expr, loc);
324 if (expr == null)
325 return false;
326
327 //
328 // Inform whether we are infinite or not
329 //
330 if (expr is BoolConstant){
331 BoolConstant bc = (BoolConstant) expr;
332
333 if (bc.Value == false){
334 if (!Statement.ResolveUnreachable (ec, true))
335 return false;
336 empty = true;
337 return true;
338 } else
339 infinite = true;
340 }
341
342 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
343 if (!infinite)
344 ec.CurrentBranching.CreateSibling ();
345
346 if (!Statement.Resolve (ec))
347 ok = false;
348
349 ec.CurrentBranching.Infinite = infinite;
350 ec.EndFlowBranching ();
351
352 return ok;
353 }
354
355 protected override void DoEmit (EmitContext ec)
356 {
357 if (empty)
358 return;
359
360 ILGenerator ig = ec.ig;
361 Label old_begin = ec.LoopBegin;
362 Label old_end = ec.LoopEnd;
363
364 ec.LoopBegin = ig.DefineLabel ();
365 ec.LoopEnd = ig.DefineLabel ();
366
367 //
368 // Inform whether we are infinite or not
369 //
370 if (expr is BoolConstant){
371 ig.MarkLabel (ec.LoopBegin);
372 Statement.Emit (ec);
373 ig.Emit (OpCodes.Br, ec.LoopBegin);
374
375 //
376 // Inform that we are infinite (ie, `we return'), only
377 // if we do not `break' inside the code.
378 //
379 ig.MarkLabel (ec.LoopEnd);
380 } else {
381 Label while_loop = ig.DefineLabel ();
382
383 ig.Emit (OpCodes.Br, ec.LoopBegin);
384 ig.MarkLabel (while_loop);
385
386 Statement.Emit (ec);
387
388 ig.MarkLabel (ec.LoopBegin);
389
390 expr.EmitBranchable (ec, while_loop, true);
391
392 ig.MarkLabel (ec.LoopEnd);
393 }
394
395 ec.LoopBegin = old_begin;
396 ec.LoopEnd = old_end;
397 }
398 }
399
400 public class For : Statement {
401 Expression Test;
402 readonly Statement InitStatement;
403 readonly Statement Increment;
404 public readonly Statement Statement;
405 bool infinite, empty;
406
407 public For (Statement initStatement,
408 Expression test,
409 Statement increment,
410 Statement statement,
411 Location l)
412 {
413 InitStatement = initStatement;
414 Test = test;
415 Increment = increment;
416 Statement = statement;
417 loc = l;
418 }
419
420 public override bool Resolve (EmitContext ec)
421 {
422 bool ok = true;
423
424 if (InitStatement != null){
425 if (!InitStatement.Resolve (ec))
426 ok = false;
427 }
428
429 if (Test != null){
430 Test = Expression.ResolveBoolean (ec, Test, loc);
431 if (Test == null)
432 ok = false;
433 else if (Test is BoolConstant){
434 BoolConstant bc = (BoolConstant) Test;
435
436 if (bc.Value == false){
437 if (!Statement.ResolveUnreachable (ec, true))
438 return false;
439 if ((Increment != null) &&
440 !Increment.ResolveUnreachable (ec, false))
441 return false;
442 empty = true;
443 return true;
444 } else
445 infinite = true;
446 }
447 } else
448 infinite = true;
449
450 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
451 if (!infinite)
452 ec.CurrentBranching.CreateSibling ();
453
454 if (!Statement.Resolve (ec))
455 ok = false;
456
457 if (Increment != null){
458 if (!Increment.Resolve (ec))
459 ok = false;
460 }
461
462 ec.CurrentBranching.Infinite = infinite;
463 ec.EndFlowBranching ();
464
465 return ok;
466 }
467
468 protected override void DoEmit (EmitContext ec)
469 {
470 if (empty)
471 return;
472
473 ILGenerator ig = ec.ig;
474 Label old_begin = ec.LoopBegin;
475 Label old_end = ec.LoopEnd;
476 Label loop = ig.DefineLabel ();
477 Label test = ig.DefineLabel ();
478
479 if (InitStatement != null && InitStatement != EmptyStatement.Value)
480 InitStatement.Emit (ec);
481
482 ec.LoopBegin = ig.DefineLabel ();
483 ec.LoopEnd = ig.DefineLabel ();
484
485 ig.Emit (OpCodes.Br, test);
486 ig.MarkLabel (loop);
487 Statement.Emit (ec);
488
489 ig.MarkLabel (ec.LoopBegin);
490 if (Increment != EmptyStatement.Value)
491 Increment.Emit (ec);
492
493 ig.MarkLabel (test);
494 //
495 // If test is null, there is no test, and we are just
496 // an infinite loop
497 //
498 if (Test != null){
499 //
500 // The Resolve code already catches the case for
501 // Test == BoolConstant (false) so we know that
502 // this is true
503 //
504 if (Test is BoolConstant)
505 ig.Emit (OpCodes.Br, loop);
506 else
507 Test.EmitBranchable (ec, loop, true);
508
509 } else
510 ig.Emit (OpCodes.Br, loop);
511 ig.MarkLabel (ec.LoopEnd);
512
513 ec.LoopBegin = old_begin;
514 ec.LoopEnd = old_end;
515 }
516 }
517
518 public class StatementExpression : Statement {
519 ExpressionStatement expr;
520
521 public StatementExpression (ExpressionStatement expr)
522 {
523 this.expr = expr;
524 loc = expr.Location;
525 }
526
527 public override bool Resolve (EmitContext ec)
528 {
529 if (expr != null)
530 expr = expr.ResolveStatement (ec);
531 return expr != null;
532 }
533
534 protected override void DoEmit (EmitContext ec)
535 {
536 expr.EmitStatement (ec);
537 }
538
539 public override string ToString ()
540 {
541 return "StatementExpression (" + expr + ")";
542 }
543 }
544
545 /// <summary>
546 /// Implements the return statement
547 /// </summary>
548 public class Return : Statement {
549 public Expression Expr;
550
551 public Return (Expression expr, Location l)
552 {
553 Expr = expr;
554 loc = l;
555 }
556
557 bool in_exc;
558
559 public override bool Resolve (EmitContext ec)
560 {
561 AnonymousContainer am = ec.CurrentAnonymousMethod;
562 if ((am != null) && am.IsIterator && ec.InIterator) {
563 Report.Error (1622, loc, "Cannot return a value from iterators. Use the yield return " +
564 "statement to return a value, or yield break to end the iteration");
565 return false;
566 }
567
568 if (ec.ReturnType == null){
569 if (Expr != null){
570 if (ec.CurrentAnonymousMethod != null){
571 Report.Error (1662, loc,
572 "Cannot convert anonymous method block to delegate type `{0}' because some of the return types in the block are not implicitly convertible to the delegate return type",
573 ec.CurrentAnonymousMethod.GetSignatureForError ());
574 }
575 Error (127, "A return keyword must not be followed by any expression when method returns void");
576 return false;
577 }
578 } else {
579 if (Expr == null){
580 Error (126, "An object of a type convertible to `{0}' is required " +
581 "for the return statement",
582 TypeManager.CSharpName (ec.ReturnType));
583 return false;
584 }
585
586 Expr = Expr.Resolve (ec);
587 if (Expr == null)
588 return false;
589
590 if (Expr.Type != ec.ReturnType) {
591 Expr = Convert.ImplicitConversionRequired (
592 ec, Expr, ec.ReturnType, loc);
593 if (Expr == null)
594 return false;
595 }
596 }
597
598 FlowBranching.UsageVector vector = ec.CurrentBranching.CurrentUsageVector;
599
600 if (ec.CurrentBranching.InTryOrCatch (true)) {
601 ec.CurrentBranching.AddFinallyVector (vector);
602 in_exc = true;
603 } else if (ec.InFinally) {
604 Error (157, "Control cannot leave the body of a finally clause");
605 return false;
606 } else
607 vector.CheckOutParameters (ec.CurrentBranching);
608
609 if (in_exc)
610 ec.NeedReturnLabel ();
611
612 ec.CurrentBranching.CurrentUsageVector.Return ();
613 return true;
614 }
615
616 protected override void DoEmit (EmitContext ec)
617 {
618 if (Expr != null) {
619 Expr.Emit (ec);
620
621 if (in_exc)
622 ec.ig.Emit (OpCodes.Stloc, ec.TemporaryReturn ());
623 }
624
625 if (in_exc)
626 ec.ig.Emit (OpCodes.Leave, ec.ReturnLabel);
627 else
628 ec.ig.Emit (OpCodes.Ret);
629 }
630 }
631
632 public class Goto : Statement {
633 string target;
634 LabeledStatement label;
635
636 public override bool Resolve (EmitContext ec)
637 {
638 label = ec.CurrentBranching.LookupLabel (target, loc);
639 if (label == null)
640 return false;
641
642 // If this is a forward goto.
643 if (!label.IsDefined)
644 label.AddUsageVector (ec.CurrentBranching.CurrentUsageVector);
645
646 ec.CurrentBranching.CurrentUsageVector.Goto ();
647 label.AddReference ();
648
649 return true;
650 }
651
652 public Goto (string label, Location l)
653 {
654 loc = l;
655 target = label;
656 }
657
658 public string Target {
659 get {
660 return target;
661 }
662 }
663
664 protected override void DoEmit (EmitContext ec)
665 {
666 Label l = label.LabelTarget (ec);
667 ec.ig.Emit (OpCodes.Br, l);
668 }
669 }
670
671 public class LabeledStatement : Statement {
672 bool defined;
673 bool referenced;
674 Label label;
675 ILGenerator ig;
676
677 FlowBranching.UsageVector vectors;
678
679 public LabeledStatement (Location l)
680 {
681 this.loc = l;
682 }
683
684 public Label LabelTarget (EmitContext ec)
685 {
686 if (defined)
687 return label;
688 ig = ec.ig;
689 label = ec.ig.DefineLabel ();
690 defined = true;
691
692 return label;
693 }
694
695 public bool IsDefined {
696 get {
697 return defined;
698 }
699 }
700
701 public bool HasBeenReferenced {
702 get {
703 return referenced;
704 }
705 }
706
707 public void AddUsageVector (FlowBranching.UsageVector vector)
708 {
709 vector = vector.Clone ();
710 vector.Next = vectors;
711 vectors = vector;
712 }
713
714 public override bool Resolve (EmitContext ec)
715 {
716 ec.CurrentBranching.Label (vectors);
717
718 return true;
719 }
720
721 protected override void DoEmit (EmitContext ec)
722 {
723 if (ig != null && ig != ec.ig) {
724 // TODO: location is wrong
725 Report.Error (1632, loc, "Control cannot leave the body of an anonymous method");
726 return;
727 }
728 LabelTarget (ec);
729 ec.ig.MarkLabel (label);
730 }
731
732 public void AddReference ()
733 {
734 referenced = true;
735 }
736 }
737
738
739 /// <summary>
740 /// `goto default' statement
741 /// </summary>
742 public class GotoDefault : Statement {
743
744 public GotoDefault (Location l)
745 {
746 loc = l;
747 }
748
749 public override bool Resolve (EmitContext ec)
750 {
751 ec.CurrentBranching.CurrentUsageVector.Goto ();
752 return true;
753 }
754
755 protected override void DoEmit (EmitContext ec)
756 {
757 if (ec.Switch == null){
758 Report.Error (153, loc, "A goto case is only valid inside a switch statement");
759 return;
760 }
761
762 if (!ec.Switch.GotDefault){
763 Report.Error (159, loc, "No such label `default:' within the scope of the goto statement");
764 return;
765 }
766 ec.ig.Emit (OpCodes.Br, ec.Switch.DefaultTarget);
767 }
768 }
769
770 /// <summary>
771 /// `goto case' statement
772 /// </summary>
773 public class GotoCase : Statement {
774 Expression expr;
775 SwitchLabel sl;
776
777 public GotoCase (Expression e, Location l)
778 {
779 expr = e;
780 loc = l;
781 }
782
783 public override bool Resolve (EmitContext ec)
784 {
785 if (ec.Switch == null){
786 Report.Error (153, loc, "A goto case is only valid inside a switch statement");
787 return false;
788 }
789
790 expr = expr.Resolve (ec);
791 if (expr == null)
792 return false;
793
794 Constant c = expr as Constant;
795 if (c == null) {
796 Error (150, "A constant value is expected");
797 return false;
798 }
799
800 c = c.ToType (ec.Switch.SwitchType, loc);
801 if (c == null)
802 return false;
803
804 object val = c.GetValue ();
805 if (val == null)
806 val = SwitchLabel.NullStringCase;
807
808 sl = (SwitchLabel) ec.Switch.Elements [val];
809
810 if (sl == null){
811 Report.Error (159, loc, "No such label `case {0}:' within the scope of the goto statement", c.GetValue () == null ? "null" : val.ToString ());
812 return false;
813 }
814
815 ec.CurrentBranching.CurrentUsageVector.Goto ();
816 return true;
817 }
818
819 protected override void DoEmit (EmitContext ec)
820 {
821 ec.ig.Emit (OpCodes.Br, sl.GetILLabelCode (ec));
822 }
823 }
824
825 public class Throw : Statement {
826 Expression expr;
827
828 public Throw (Expression expr, Location l)
829 {
830 this.expr = expr;
831 loc = l;
832 }
833
834 public override bool Resolve (EmitContext ec)
835 {
836 ec.CurrentBranching.CurrentUsageVector.Throw ();
837
838 if (expr != null){
839 expr = expr.Resolve (ec);
840 if (expr == null)
841 return false;
842
843 ExprClass eclass = expr.eclass;
844
845 if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
846 eclass == ExprClass.Value || eclass == ExprClass.IndexerAccess)) {
847 expr.Error_UnexpectedKind (ec.DeclContainer, "value, variable, property or indexer access ", loc);
848 return false;
849 }
850
851 Type t = expr.Type;
852
853 if ((t != TypeManager.exception_type) &&
854 !TypeManager.IsSubclassOf (t, TypeManager.exception_type) &&
855 !(expr is NullLiteral)) {
856 Error (155,
857 "The type caught or thrown must be derived " +
858 "from System.Exception");
859 return false;
860 }
861 return true;
862 }
863
864 if (!ec.InCatch) {
865 Error (156, "A throw statement with no arguments is not allowed outside of a catch clause");
866 return false;
867 }
868
869 if (ec.InFinally) {
870 Error (724, "A throw statement with no arguments is not allowed inside of a finally clause nested inside of the innermost catch clause");
871 return false;
872 }
873 return true;
874 }
875
876 protected override void DoEmit (EmitContext ec)
877 {
878 if (expr == null)
879 ec.ig.Emit (OpCodes.Rethrow);
880 else {
881 expr.Emit (ec);
882
883 ec.ig.Emit (OpCodes.Throw);
884 }
885 }
886 }
887
888 public class Break : Statement {
889
890 public Break (Location l)
891 {
892 loc = l;
893 }
894
895 bool crossing_exc;
896
897 public override bool Resolve (EmitContext ec)
898 {
899 if (!ec.CurrentBranching.InLoop () && !ec.CurrentBranching.InSwitch ()){
900 Error (139, "No enclosing loop out of which to break or continue");
901 return false;
902 } else if (ec.InFinally && ec.CurrentBranching.BreakCrossesTryCatchBoundary()) {
903 Error (157, "Control cannot leave the body of a finally clause");
904 return false;
905 } else if (ec.CurrentBranching.InTryOrCatch (false))
906 ec.CurrentBranching.AddFinallyVector (
907 ec.CurrentBranching.CurrentUsageVector);
908 else if (ec.CurrentBranching.InLoop () || ec.CurrentBranching.InSwitch ())
909 ec.CurrentBranching.AddBreakVector (
910 ec.CurrentBranching.CurrentUsageVector);
911
912 crossing_exc = ec.CurrentBranching.BreakCrossesTryCatchBoundary ();
913
914 if (!crossing_exc)
915 ec.NeedReturnLabel ();
916
917 ec.CurrentBranching.CurrentUsageVector.Break ();
918 return true;
919 }
920
921 protected override void DoEmit (EmitContext ec)
922 {
923 ILGenerator ig = ec.ig;
924
925 if (crossing_exc)
926 ig.Emit (OpCodes.Leave, ec.LoopEnd);
927 else {
928 ig.Emit (OpCodes.Br, ec.LoopEnd);
929 }
930 }
931 }
932
933 public class Continue : Statement {
934
935 public Continue (Location l)
936 {
937 loc = l;
938 }
939
940 bool crossing_exc;
941
942 public override bool Resolve (EmitContext ec)
943 {
944 if (!ec.CurrentBranching.InLoop ()){
945 Error (139, "No enclosing loop out of which to break or continue");
946 return false;
947 } else if (ec.InFinally) {
948 Error (157, "Control cannot leave the body of a finally clause");
949 return false;
950 } else if (ec.CurrentBranching.InTryOrCatch (false))
951 ec.CurrentBranching.AddFinallyVector (ec.CurrentBranching.CurrentUsageVector);
952
953 crossing_exc = ec.CurrentBranching.BreakCrossesTryCatchBoundary ();
954
955 ec.CurrentBranching.CurrentUsageVector.Goto ();
956 return true;
957 }
958
959 protected override void DoEmit (EmitContext ec)
960 {
961 Label begin = ec.LoopBegin;
962
963 if (crossing_exc)
964 ec.ig.Emit (OpCodes.Leave, begin);
965 else
966 ec.ig.Emit (OpCodes.Br, begin);
967 }
968 }
969
970 //
971 // The information about a user-perceived local variable
972 //
973 public class LocalInfo {
974 public Expression Type;
975
976 //
977 // Most of the time a variable will be stored in a LocalBuilder
978 //
979 // But sometimes, it will be stored in a field (variables that have been
980 // hoisted by iterators or by anonymous methods). The context of the field will
981 // be stored in the EmitContext
982 //
983 //
984 public LocalBuilder LocalBuilder;
985 public FieldBuilder FieldBuilder;
986
987 public Type VariableType;
988 public readonly string Name;
989 public readonly Location Location;
990 public readonly Block Block;
991
992 public VariableInfo VariableInfo;
993
994 enum Flags : byte {
995 Used = 1,
996 ReadOnly = 2,
997 Pinned = 4,
998 IsThis = 8,
999 Captured = 16,
1000 AddressTaken = 32,
1001 CompilerGenerated = 64
1002 }
1003
1004 public enum ReadOnlyContext: byte {
1005 Using,
1006 Foreach,
1007 Fixed
1008 }
1009
1010 Flags flags;
1011 ReadOnlyContext ro_context;
1012
1013 public LocalInfo (Expression type, string name, Block block, Location l)
1014 {
1015 Type = type;
1016 Name = name;
1017 Block = block;
1018 Location = l;
1019 }
1020
1021 public LocalInfo (DeclSpace ds, Block block, Location l)
1022 {
1023 VariableType = ds.TypeBuilder;
1024 Block = block;
1025 Location = l;
1026 }
1027
1028 public bool IsThisAssigned (EmitContext ec, Location loc)
1029 {
1030 if (VariableInfo == null)
1031 throw new Exception ();
1032
1033 if (!ec.DoFlowAnalysis || ec.CurrentBranching.IsAssigned (VariableInfo))
1034 return true;
1035
1036 return VariableInfo.TypeInfo.IsFullyInitialized (ec.CurrentBranching, VariableInfo, loc);
1037 }
1038
1039 public bool IsAssigned (EmitContext ec)
1040 {
1041 if (VariableInfo == null)
1042 throw new Exception ();
1043
1044 return !ec.DoFlowAnalysis || ec.CurrentBranching.IsAssigned (VariableInfo);
1045 }
1046
1047 public bool Resolve (EmitContext ec)
1048 {
1049 if (VariableType == null) {
1050 TypeExpr texpr = Type.ResolveAsTypeTerminal (ec, false);
1051 if (texpr == null)
1052 return false;
1053
1054 VariableType = texpr.Type;
1055 }
1056
1057 if (VariableType == TypeManager.void_type) {
1058 Report.Error (1547, Location,
1059 "Keyword 'void' cannot be used in this context");
1060 return false;
1061 }
1062
1063 if (VariableType.IsAbstract && VariableType.IsSealed) {
1064 Report.Error (723, Location, "Cannot declare variable of static type `{0}'", TypeManager.CSharpName (VariableType));
1065 return false;
1066 }
1067
1068 if (VariableType.IsPointer && !ec.InUnsafe)
1069 Expression.UnsafeError (Location);
1070
1071 return true;
1072 }
1073
1074 public bool IsCaptured {
1075 get {
1076 return (flags & Flags.Captured) != 0;
1077 }
1078
1079 set {
1080 flags |= Flags.Captured;
1081 }
1082 }
1083
1084 public bool AddressTaken {
1085 get {
1086 return (flags & Flags.AddressTaken) != 0;
1087 }
1088
1089 set {
1090 flags |= Flags.AddressTaken;
1091 }
1092 }
1093
1094 public bool CompilerGenerated {
1095 get {
1096 return (flags & Flags.CompilerGenerated) != 0;
1097 }
1098
1099 set {
1100 flags |= Flags.CompilerGenerated;
1101 }
1102 }
1103
1104 public override string ToString ()
1105 {
1106 return String.Format ("LocalInfo ({0},{1},{2},{3})",
1107 Name, Type, VariableInfo, Location);
1108 }
1109
1110 public bool Used {
1111 get {
1112 return (flags & Flags.Used) != 0;
1113 }
1114 set {
1115 flags = value ? (flags | Flags.Used) : (unchecked (flags & ~Flags.Used));
1116 }
1117 }
1118
1119 public bool ReadOnly {
1120 get {
1121 return (flags & Flags.ReadOnly) != 0;
1122 }
1123 }
1124
1125 public void SetReadOnlyContext (ReadOnlyContext context)
1126 {
1127 flags |= Flags.ReadOnly;
1128 ro_context = context;
1129 }
1130
1131 public string GetReadOnlyContext ()
1132 {
1133 if (!ReadOnly)
1134 throw new InternalErrorException ("Variable is not readonly");
1135
1136 switch (ro_context) {
1137 case ReadOnlyContext.Fixed:
1138 return "fixed variable";
1139 case ReadOnlyContext.Foreach:
1140 return "foreach iteration variable";
1141 case ReadOnlyContext.Using:
1142 return "using variable";
1143 }
1144 throw new NotImplementedException ();
1145 }
1146
1147 //
1148 // Whether the variable is pinned, if Pinned the variable has been
1149 // allocated in a pinned slot with DeclareLocal.
1150 //
1151 public bool Pinned {
1152 get {
1153 return (flags & Flags.Pinned) != 0;
1154 }
1155 set {
1156 flags = value ? (flags | Flags.Pinned) : (flags & ~Flags.Pinned);
1157 }
1158 }
1159
1160 public bool IsThis {
1161 get {
1162 return (flags & Flags.IsThis) != 0;
1163 }
1164 set {
1165 flags = value ? (flags | Flags.IsThis) : (flags & ~Flags.IsThis);
1166 }
1167 }
1168 }
1169
1170 /// <summary>
1171 /// Block represents a C# block.
1172 /// </summary>
1173 ///
1174 /// <remarks>
1175 /// This class is used in a number of places: either to represent
1176 /// explicit blocks that the programmer places or implicit blocks.
1177 ///
1178 /// Implicit blocks are used as labels or to introduce variable
1179 /// declarations.
1180 ///
1181 /// Top-level blocks derive from Block, and they are called ToplevelBlock
1182 /// they contain extra information that is not necessary on normal blocks.
1183 /// </remarks>
1184 public class Block : Statement {
1185 public Block Parent;
1186 public readonly Location StartLocation;
1187 public Location EndLocation = Location.Null;
1188
1189 public readonly ToplevelBlock Toplevel;
1190
1191 [Flags]
1192 public enum Flags : ushort {
1193 Implicit = 1,
1194 Unchecked = 2,
1195 BlockUsed = 4,
1196 VariablesInitialized = 8,
1197 HasRet = 16,
1198 IsDestructor = 32,
1199 IsToplevel = 64,
1200 Unsafe = 128,
1201 HasVarargs = 256 // Used in ToplevelBlock
1202 }
1203 protected Flags flags;
1204
1205 public bool Implicit {
1206 get { return (flags & Flags.Implicit) != 0; }
1207 }
1208
1209 public bool Unchecked {
1210 get { return (flags & Flags.Unchecked) != 0; }
1211 set { flags |= Flags.Unchecked; }
1212 }
1213
1214 public bool Unsafe {
1215 get { return (flags & Flags.Unsafe) != 0; }
1216 set { flags |= Flags.Unsafe; }
1217 }
1218
1219 //
1220 // The statements in this block
1221 //
1222 ArrayList statements;
1223 int num_statements;
1224
1225 //
1226 // An array of Blocks. We keep track of children just
1227 // to generate the local variable declarations.
1228 //
1229 // Statements and child statements are handled through the
1230 // statements.
1231 //
1232 ArrayList children;
1233
1234 //
1235 // Labels. (label, block) pairs.
1236 //
1237 Hashtable labels;
1238
1239 //
1240 // Keeps track of (name, type) pairs
1241 //
1242 IDictionary variables;
1243
1244 //
1245 // Keeps track of constants
1246 Hashtable constants;
1247
1248 //
1249 // Temporary variables.
1250 //
1251 ArrayList temporary_variables;
1252
1253 //
1254 // If this is a switch section, the enclosing switch block.
1255 //
1256 Block switch_block;
1257
1258 protected static int id;
1259
1260 int this_id;
1261
1262 public Block (Block parent)
1263 : this (parent, (Flags) 0, Location.Null, Location.Null)
1264 { }
1265
1266 public Block (Block parent, Flags flags)
1267 : this (parent, flags, Location.Null, Location.Null)
1268 { }
1269
1270 public Block (Block parent, Location start, Location end)
1271 : this (parent, (Flags) 0, start, end)
1272 { }
1273
1274 public Block (Block parent, Flags flags, Location start, Location end)
1275 {
1276 if (parent != null)
1277 parent.AddChild (this);
1278
1279 this.Parent = parent;
1280 this.flags = flags;
1281 this.StartLocation = start;
1282 this.EndLocation = end;
1283 this.loc = start;
1284 this_id = id++;
1285 statements = new ArrayList ();
1286
1287 if ((flags & Flags.IsToplevel) != 0)
1288 Toplevel = (ToplevelBlock) this;
1289 else
1290 Toplevel = parent.Toplevel;
1291
1292 if (parent != null && Implicit) {
1293 if (parent.known_variables == null)
1294 parent.known_variables = new Hashtable ();
1295 // share with parent
1296 known_variables = parent.known_variables;
1297 }
1298 }
1299
1300 public Block CreateSwitchBlock (Location start)
1301 {
1302 Block new_block = new Block (this, start, start);
1303 new_block.switch_block = this;
1304 return new_block;
1305 }
1306
1307 public int ID {
1308 get { return this_id; }
1309 }
1310
1311 protected IDictionary Variables {
1312 get {
1313 if (variables == null)
1314 variables = new ListDictionary ();
1315 return variables;
1316 }
1317 }
1318
1319 void AddChild (Block b)
1320 {
1321 if (children == null)
1322 children = new ArrayList ();
1323
1324 children.Add (b);
1325 }
1326
1327 public void SetEndLocation (Location loc)
1328 {
1329 EndLocation = loc;
1330 }
1331
1332 /// <summary>
1333 /// Adds a label to the current block.
1334 /// </summary>
1335 ///
1336 /// <returns>
1337 /// false if the name already exists in this block. true
1338 /// otherwise.
1339 /// </returns>
1340 ///
1341 public bool AddLabel (string name, LabeledStatement target, Location loc)
1342 {
1343 if (switch_block != null)
1344 return switch_block.AddLabel (name, target, loc);
1345
1346 Block cur = this;
1347 while (cur != null) {
1348 if (cur.DoLookupLabel (name) != null) {
1349 Report.Error (
1350 140, loc, "The label `{0}' is a duplicate",
1351 name);
1352 return false;
1353 }
1354
1355 if (!Implicit)
1356 break;
1357
1358 cur = cur.Parent;
1359 }
1360
1361 while (cur != null) {
1362 if (cur.DoLookupLabel (name) != null) {
1363 Report.Error (
1364 158, loc,
1365 "The label `{0}' shadows another label " +
1366 "by the same name in a contained scope.",
1367 name);
1368 return false;
1369 }
1370
1371 if (children != null) {
1372 foreach (Block b in children) {
1373 LabeledStatement s = b.DoLookupLabel (name);
1374 if (s == null)
1375 continue;
1376
1377 Report.Error (
1378 158, s.loc,
1379 "The label `{0}' shadows another " +
1380 "label by the same name in a " +
1381 "contained scope.",
1382 name);
1383 return false;
1384 }
1385 }
1386
1387
1388 cur = cur.Parent;
1389 }
1390
1391 if (labels == null)
1392 labels = new Hashtable ();
1393
1394 labels.Add (name, target);
1395 return true;
1396 }
1397
1398 public LabeledStatement LookupLabel (string name)
1399 {
1400 LabeledStatement s = DoLookupLabel (name);
1401 if (s != null)
1402 return s;
1403
1404 if (children == null)
1405 return null;
1406
1407 foreach (Block child in children) {
1408 if (!child.Implicit)
1409 continue;
1410
1411 s = child.LookupLabel (name);
1412 if (s != null)
1413 return s;
1414 }
1415
1416 return null;
1417 }
1418
1419 LabeledStatement DoLookupLabel (string name)
1420 {
1421 if (switch_block != null)
1422 return switch_block.LookupLabel (name);
1423
1424 if (labels != null)
1425 if (labels.Contains (name))
1426 return ((LabeledStatement) labels [name]);
1427
1428 return null;
1429 }
1430
1431 Hashtable known_variables;
1432
1433 // <summary>
1434 // Marks a variable with name @name as being used in this or a child block.
1435 // If a variable name has been used in a child block, it's illegal to
1436 // declare a variable with the same name in the current block.
1437 // </summary>
1438 void AddKnownVariable (string name, LocalInfo info)
1439 {
1440 if (known_variables == null)
1441 known_variables = new Hashtable ();
1442
1443 known_variables [name] = info;
1444 }
1445
1446 LocalInfo GetKnownVariableInfo (string name)
1447 {
1448 if (known_variables == null)
1449 return null;
1450 return (LocalInfo) known_variables [name];
1451 }
1452
1453 public bool CheckInvariantMeaningInBlock (string name, Expression e, Location loc)
1454 {
1455 Block b = this;
1456 LocalInfo kvi = b.GetKnownVariableInfo (name);
1457 while (kvi == null) {
1458 while (b.Implicit)
1459 b = b.Parent;
1460 b = b.Parent;
1461 if (b == null)
1462 return true;
1463 kvi = b.GetKnownVariableInfo (name);
1464 }
1465
1466 if (kvi.Block == b)
1467 return true;
1468
1469 // Is kvi.Block nested inside 'b'
1470 if (b.known_variables != kvi.Block.known_variables) {
1471 //
1472 // If a variable by the same name it defined in a nested block of this
1473 // block, we violate the invariant meaning in a block.
1474 //
1475 if (b == this) {
1476 Report.SymbolRelatedToPreviousError (kvi.Location, name);
1477 Report.Error (135, loc, "`{0}' conflicts with a declaration in a child block", name);
1478 return false;
1479 }
1480
1481 //
1482 // It's ok if the definition is in a nested subblock of b, but not
1483 // nested inside this block -- a definition in a sibling block
1484 // should not affect us.
1485 //
1486 return true;
1487 }
1488
1489 //
1490 // Block 'b' and kvi.Block are the same textual block.
1491 // However, different variables are extant.
1492 //
1493 // Check if the variable is in scope in both blocks. We use
1494 // an indirect check that depends on AddVariable doing its
1495 // part in maintaining the invariant-meaning-in-block property.
1496 //
1497 if (e is LocalVariableReference || (e is Constant && b.GetLocalInfo (name) != null))
1498 return true;
1499
1500 //
1501 // Even though we detected the error when the name is used, we
1502 // treat it as if the variable declaration was in error.
1503 //
1504 Report.SymbolRelatedToPreviousError (loc, name);
1505 Error_AlreadyDeclared (kvi.Location, name, "parent or current");
1506 return false;
1507 }
1508
1509 public LocalInfo AddVariable (Expression type, string name, Location l)
1510 {
1511 LocalInfo vi = GetLocalInfo (name);
1512 if (vi != null) {
1513 Report.SymbolRelatedToPreviousError (vi.Location, name);
1514 if (known_variables == vi.Block.known_variables)
1515 Report.Error (128, l,
1516 "A local variable named `{0}' is already defined in this scope", name);
1517 else
1518 Error_AlreadyDeclared (l, name, "parent");
1519 return null;
1520 }
1521
1522 vi = GetKnownVariableInfo (name);
1523 if (vi != null) {
1524 Report.SymbolRelatedToPreviousError (vi.Location, name);
1525 Error_AlreadyDeclared (l, name, "child");
1526 return null;
1527 }
1528
1529 int idx;
1530 Parameter p = Toplevel.Parameters.GetParameterByName (name, out idx);
1531 if (p != null) {
1532 Report.SymbolRelatedToPreviousError (p.Location, name);
1533 Error_AlreadyDeclared (l, name, "method argument");
1534 return null;
1535 }
1536
1537 vi = new LocalInfo (type, name, this, l);
1538
1539 Variables.Add (name, vi);
1540
1541 for (Block b = this; b != null; b = b.Parent)
1542 b.AddKnownVariable (name, vi);
1543
1544 if ((flags & Flags.VariablesInitialized) != 0)
1545 throw new Exception ();
1546
1547 return vi;
1548 }
1549
1550 void Error_AlreadyDeclared (Location loc, string var, string reason)
1551 {
1552 Report.Error (136, loc, "A local variable named `{0}' cannot be declared in this scope because it would give a different meaning to `{0}', " +
1553 "which is already used in a `{1}' scope", var, reason);
1554 }
1555
1556 public bool AddConstant (Expression type, string name, Expression value, Location l)
1557 {
1558 if (AddVariable (type, name, l) == null)
1559 return false;
1560
1561 if (constants == null)
1562 constants = new Hashtable ();
1563
1564 constants.Add (name, value);
1565
1566 // A block is considered used if we perform an initialization in a local declaration, even if it is constant.
1567 Use ();
1568 return true;
1569 }
1570
1571 static int next_temp_id = 0;
1572
1573 public LocalInfo AddTemporaryVariable (TypeExpr te, Location loc)
1574 {
1575 if (temporary_variables == null)
1576 temporary_variables = new ArrayList ();
1577
1578 int id = ++next_temp_id;
1579 string name = "$s_" + id.ToString ();
1580
1581 LocalInfo li = new LocalInfo (te, name, this, loc);
1582 li.CompilerGenerated = true;
1583 temporary_variables.Add (li);
1584 return li;
1585 }
1586
1587 public LocalInfo GetLocalInfo (string name)
1588 {
1589 for (Block b = this; b != null; b = b.Parent) {
1590 if (b.variables != null) {
1591 LocalInfo ret = b.variables [name] as LocalInfo;
1592 if (ret != null)
1593 return ret;
1594 }
1595 }
1596 return null;
1597 }
1598
1599 public Expression GetVariableType (string name)
1600 {
1601 LocalInfo vi = GetLocalInfo (name);
1602 return vi == null ? null : vi.Type;
1603 }
1604
1605 public Expression GetConstantExpression (string name)
1606 {
1607 for (Block b = this; b != null; b = b.Parent) {
1608 if (b.constants != null) {
1609 Expression ret = b.constants [name] as Expression;
1610 if (ret != null)
1611 return ret;
1612 }
1613 }
1614 return null;
1615 }
1616
1617 public void AddStatement (Statement s)
1618 {
1619 statements.Add (s);
1620 flags |= Flags.BlockUsed;
1621 }
1622
1623 public bool Used {
1624 get { return (flags & Flags.BlockUsed) != 0; }
1625 }
1626
1627 public void Use ()
1628 {
1629 flags |= Flags.BlockUsed;
1630 }
1631
1632 public bool HasRet {
1633 get { return (flags & Flags.HasRet) != 0; }
1634 }
1635
1636 public bool IsDestructor {
1637 get { return (flags & Flags.IsDestructor) != 0; }
1638 }
1639
1640 public void SetDestructor ()
1641 {
1642 flags |= Flags.IsDestructor;
1643 }
1644
1645 VariableMap param_map, local_map;
1646
1647 public VariableMap ParameterMap {
1648 get {
1649 if ((flags & Flags.VariablesInitialized) == 0)
1650 throw new Exception ("Variables have not been initialized yet");
1651
1652 return param_map;
1653 }
1654 }
1655
1656 public VariableMap LocalMap {
1657 get {
1658 if ((flags & Flags.VariablesInitialized) == 0)
1659 throw new Exception ("Variables have not been initialized yet");
1660
1661 return local_map;
1662 }
1663 }
1664
1665 /// <summary>
1666 /// Emits the variable declarations and labels.
1667 /// </summary>
1668 /// <remarks>
1669 /// tc: is our typecontainer (to resolve type references)
1670 /// ig: is the code generator:
1671 /// </remarks>
1672 public void ResolveMeta (ToplevelBlock toplevel, EmitContext ec, Parameters ip)
1673 {
1674 bool old_unsafe = ec.InUnsafe;
1675
1676 // If some parent block was unsafe, we remain unsafe even if this block
1677 // isn't explicitly marked as such.
1678 ec.InUnsafe |= Unsafe;
1679
1680 //
1681 // Compute the VariableMap's.
1682 //
1683 // Unfortunately, we don't know the type when adding variables with
1684 // AddVariable(), so we need to compute this info here.
1685 //
1686
1687 LocalInfo[] locals;
1688 if (variables != null) {
1689 foreach (LocalInfo li in variables.Values)
1690 li.Resolve (ec);
1691
1692 locals = new LocalInfo [variables.Count];
1693 variables.Values.CopyTo (locals, 0);
1694 } else
1695 locals = new LocalInfo [0];
1696
1697 if (Parent != null)
1698 local_map = new VariableMap (Parent.LocalMap, locals);
1699 else
1700 local_map = new VariableMap (locals);
1701
1702 param_map = new VariableMap (ip);
1703 flags |= Flags.VariablesInitialized;
1704
1705 bool old_check_state = ec.ConstantCheckState;
1706 ec.ConstantCheckState = (flags & Flags.Unchecked) == 0;
1707
1708 //
1709 // Process this block variables
1710 //
1711 if (variables != null){
1712 foreach (DictionaryEntry de in variables){
1713 string name = (string) de.Key;
1714 LocalInfo vi = (LocalInfo) de.Value;
1715
1716 if (vi.VariableType == null)
1717 continue;
1718
1719 Type variable_type = vi.VariableType;
1720
1721 if (variable_type.IsPointer){
1722 //
1723 // Am not really convinced that this test is required (Microsoft does it)
1724 // but the fact is that you would not be able to use the pointer variable
1725 // *anyways*
1726 //
1727 if (!TypeManager.VerifyUnManaged (TypeManager.GetElementType (variable_type),
1728 vi.Location))
1729 continue;
1730 }
1731
1732 if (constants == null)
1733 continue;
1734
1735 Expression cv = (Expression) constants [name];
1736 if (cv == null)
1737 continue;
1738
1739 // Don't let 'const int Foo = Foo;' succeed.
1740 // Removing the name from 'constants' ensures that we get a LocalVariableReference below,
1741 // which in turn causes the 'must be constant' error to be triggered.
1742 constants.Remove (name);
1743
1744 ec.CurrentBlock = this;
1745 Expression e = cv.Resolve (ec);
1746 if (e == null)
1747 continue;
1748
1749 Constant ce = e as Constant;
1750 if (ce == null){
1751 Const.Error_ExpressionMustBeConstant (vi.Location, name);
1752 continue;
1753 }
1754
1755 e = ce.ToType (variable_type, vi.Location);
1756 if (e == null)
1757 continue;
1758
1759 if (!variable_type.IsValueType && variable_type != TypeManager.string_type && !ce.IsDefaultValue) {
1760 Const.Error_ConstantCanBeInitializedWithNullOnly (vi.Location, vi.Name);
1761 continue;
1762 }
1763
1764 constants.Add (name, e);
1765 }
1766 }
1767 ec.ConstantCheckState = old_check_state;
1768
1769 //
1770 // Now, handle the children
1771 //
1772 if (children != null){
1773 foreach (Block b in children)
1774 b.ResolveMeta (toplevel, ec, ip);
1775 }
1776 ec.InUnsafe = old_unsafe;
1777 }
1778
1779 //
1780 // Emits the local variable declarations for a block
1781 //
1782 public void EmitMeta (EmitContext ec)
1783 {
1784 ILGenerator ig = ec.ig;
1785
1786 if (variables != null){
1787 bool have_captured_vars = ec.HaveCapturedVariables ();
1788
1789 foreach (DictionaryEntry de in variables){
1790 LocalInfo vi = (LocalInfo) de.Value;
1791
1792 if (have_captured_vars && ec.IsCaptured (vi))
1793 continue;
1794
1795 if (vi.Pinned)
1796 //
1797 // This is needed to compile on both .NET 1.x and .NET 2.x
1798 // the later introduced `DeclareLocal (Type t, bool pinned)'
1799 //
1800 vi.LocalBuilder = TypeManager.DeclareLocalPinned (ig, vi.VariableType);
1801 else if (!vi.IsThis)
1802 vi.LocalBuilder = ig.DeclareLocal (vi.VariableType);
1803 }
1804 }
1805
1806 if (temporary_variables != null) {
1807 AnonymousContainer am = ec.CurrentAnonymousMethod;
1808 TypeBuilder scope = null;
1809 if ((am != null) && am.IsIterator) {
1810 scope = am.Scope.ScopeTypeBuilder;
1811 if (scope == null)
1812 throw new InternalErrorException ();
1813 }
1814 foreach (LocalInfo vi in temporary_variables) {
1815 if (scope != null) {
1816 if (vi.FieldBuilder == null)
1817 vi.FieldBuilder = scope.DefineField (
1818 vi.Name, vi.VariableType, FieldAttributes.Assembly);
1819 } else
1820 vi.LocalBuilder = ig.DeclareLocal (vi.VariableType);
1821 }
1822 }
1823
1824 if (children != null){
1825 foreach (Block b in children)
1826 b.EmitMeta (ec);
1827 }
1828 }
1829
1830 void UsageWarning (FlowBranching.UsageVector vector)
1831 {
1832 string name;
1833
1834 if ((variables != null) && (RootContext.WarningLevel >= 3)) {
1835 foreach (DictionaryEntry de in variables){
1836 LocalInfo vi = (LocalInfo) de.Value;
1837
1838 if (vi.Used)
1839 continue;
1840
1841 name = (string) de.Key;
1842
1843 // vi.VariableInfo can be null for 'catch' variables
1844 if (vi.VariableInfo != null && vector.IsAssigned (vi.VariableInfo)){
1845 Report.Warning (219, 3, vi.Location, "The variable `{0}' is assigned but its value is never used", name);
1846 } else {
1847 Report.Warning (168, 3, vi.Location, "The variable `{0}' is declared but never used", name);
1848 }
1849 }
1850 }
1851 }
1852
1853 bool unreachable_shown;
1854 bool unreachable;
1855
1856 private void CheckPossibleMistakenEmptyStatement (Statement s)
1857 {
1858 Statement body;
1859
1860 // Some statements are wrapped by a Block. Since
1861 // others' internal could be changed, here I treat
1862 // them as possibly wrapped by Block equally.
1863 Block b = s as Block;
1864 if (b != null && b.statements.Count == 1)
1865 s = (Statement) b.statements [0];
1866
1867 if (s is Lock)
1868 body = ((Lock) s).Statement;
1869 else if (s is For)
1870 body = ((For) s).Statement;
1871 else if (s is Foreach)
1872 body = ((Foreach) s).Statement;
1873 else if (s is While)
1874 body = ((While) s).Statement;
1875 else if (s is Using)
1876 body = ((Using) s).Statement;
1877 else if (s is Fixed)
1878 body = ((Fixed) s).Statement;
1879 else
1880 return;
1881
1882 if (body == null || body is EmptyStatement)
1883 Report.Warning (642, 3, s.loc, "Possible mistaken empty statement");
1884 }
1885
1886 public override bool Resolve (EmitContext ec)
1887 {
1888 Block prev_block = ec.CurrentBlock;
1889 bool ok = true;
1890
1891 int errors = Report.Errors;
1892
1893 ec.CurrentBlock = this;
1894 ec.StartFlowBranching (this);
1895
1896 Report.Debug (4, "RESOLVE BLOCK", StartLocation, ec.CurrentBranching);
1897
1898 //
1899 // This flag is used to notate nested statements as unreachable from the beginning of this block.
1900 // For the purposes of this resolution, it doesn't matter that the whole block is unreachable
1901 // from the beginning of the function. The outer Resolve() that detected the unreachability is
1902 // responsible for handling the situation.
1903 //
1904 int statement_count = statements.Count;
1905 for (int ix = 0; ix < statement_count; ix++){
1906 Statement s = (Statement) statements [ix];
1907 // Check possible empty statement (CS0642)
1908 if (RootContext.WarningLevel >= 3 &&
1909 ix + 1 < statement_count &&
1910 statements [ix + 1] is Block)
1911 CheckPossibleMistakenEmptyStatement (s);
1912
1913 if (unreachable) {
1914 if (s is EmptyStatement)
1915 continue;
1916
1917 if (s is Block)
1918 ((Block) s).unreachable = true;
1919
1920 if (!unreachable_shown) {
1921 Report.Warning (162, 2, s.loc, "Unreachable code detected");
1922 unreachable_shown = true;
1923 }
1924 }
1925
1926 if (!s.Resolve (ec)) {
1927 ok = false;
1928 statements [ix] = EmptyStatement.Value;
1929 continue;
1930 }
1931
1932 if (unreachable && !(s is LabeledStatement) && !(s is Block))
1933 statements [ix] = EmptyStatement.Value;
1934
1935 num_statements = ix + 1;
1936 if (s is LabeledStatement)
1937 unreachable = false;
1938 else
1939 unreachable = ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable;
1940 }
1941
1942 Report.Debug (4, "RESOLVE BLOCK DONE", StartLocation,
1943 ec.CurrentBranching, statement_count, num_statements);
1944
1945 FlowBranching.UsageVector vector = ec.DoEndFlowBranching ();
1946
1947 ec.CurrentBlock = prev_block;
1948
1949 // If we're a non-static `struct' constructor which doesn't have an
1950 // initializer, then we must initialize all of the struct's fields.
1951 if ((flags & Flags.IsToplevel) != 0 &&
1952 !Toplevel.IsThisAssigned (ec) &&
1953 vector.Reachability.Throws != FlowBranching.FlowReturns.Always)
1954 ok = false;
1955
1956 if ((labels != null) && (RootContext.WarningLevel >= 2)) {
1957 foreach (LabeledStatement label in labels.Values)
1958 if (!label.HasBeenReferenced)
1959 Report.Warning (164, 2, label.loc,
1960 "This label has not been referenced");
1961 }
1962
1963 Report.Debug (4, "RESOLVE BLOCK DONE #2", StartLocation, vector);
1964
1965 if ((vector.Reachability.Returns == FlowBranching.FlowReturns.Always) ||
1966 (vector.Reachability.Throws == FlowBranching.FlowReturns.Always) ||
1967 (vector.Reachability.Reachable == FlowBranching.FlowReturns.Never))
1968 flags |= Flags.HasRet;
1969
1970 if (ok && (errors == Report.Errors)) {
1971 if (RootContext.WarningLevel >= 3)
1972 UsageWarning (vector);
1973 }
1974
1975 return ok;
1976 }
1977
1978 public override bool ResolveUnreachable (EmitContext ec, bool warn)
1979 {
1980 unreachable_shown = true;
1981 unreachable = true;
1982
1983 if (warn)
1984 Report.Warning (162, 2, loc, "Unreachable code detected");
1985
1986 ec.StartFlowBranching (FlowBranching.BranchingType.Block, loc);
1987 bool ok = Resolve (ec);
1988 ec.KillFlowBranching ();
1989
1990 return ok;
1991 }
1992
1993 protected override void DoEmit (EmitContext ec)
1994 {
1995 for (int ix = 0; ix < num_statements; ix++){
1996 Statement s = (Statement) statements [ix];
1997
1998 // Check whether we are the last statement in a
1999 // top-level block.
2000
2001 if (((Parent == null) || Implicit) && (ix+1 == num_statements) && !(s is Block))
2002 ec.IsLastStatement = true;
2003 else
2004 ec.IsLastStatement = false;
2005
2006 s.Emit (ec);
2007 }
2008 }
2009
2010 public override void Emit (EmitContext ec)
2011 {
2012 Block prev_block = ec.CurrentBlock;
2013
2014 ec.CurrentBlock = this;
2015
2016 bool emit_debug_info = (CodeGen.SymbolWriter != null);
2017 bool is_lexical_block = !Implicit && (Parent != null);
2018
2019 if (emit_debug_info) {
2020 if (is_lexical_block)
2021 ec.BeginScope ();
2022
2023 if (variables != null) {
2024 foreach (DictionaryEntry de in variables) {
2025 string name = (string) de.Key;
2026 LocalInfo vi = (LocalInfo) de.Value;
2027
2028 if (vi.LocalBuilder == null)
2029 continue;
2030
2031 ec.DefineLocalVariable (name, vi.LocalBuilder);
2032 }
2033 }
2034 }
2035 ec.Mark (StartLocation, true);
2036 ec.EmitScopeInitFromBlock (this);
2037 DoEmit (ec);
2038 ec.Mark (EndLocation, true);
2039
2040 if (emit_debug_info && is_lexical_block)
2041 ec.EndScope ();
2042
2043 ec.CurrentBlock = prev_block;
2044 }
2045
2046 //
2047 // Returns true if we ar ea child of `b'.
2048 //
2049 public bool IsChildOf (Block b)
2050 {
2051 Block current = this;
2052
2053 do {
2054 if (current.Parent == b)
2055 return true;
2056 current = current.Parent;
2057 } while (current != null);
2058 return false;
2059 }
2060
2061 public override string ToString ()
2062 {
2063 return String.Format ("{0} ({1}:{2})", GetType (),ID, StartLocation);
2064 }
2065 }
2066
2067 //
2068 // A toplevel block contains extra information, the split is done
2069 // only to separate information that would otherwise bloat the more
2070 // lightweight Block.
2071 //
2072 // In particular, this was introduced when the support for Anonymous
2073 // Methods was implemented.
2074 //
2075 public class ToplevelBlock : Block {
2076 //
2077 // Pointer to the host of this anonymous method, or null
2078 // if we are the topmost block
2079 //
2080 ToplevelBlock container;
2081 CaptureContext capture_context;
2082 FlowBranching top_level_branching;
2083
2084 Hashtable capture_contexts;
2085 ArrayList children;
2086
2087 public bool HasVarargs {
2088 get { return (flags & Flags.HasVarargs) != 0; }
2089 set { flags |= Flags.HasVarargs; }
2090 }
2091
2092 //
2093 // The parameters for the block.
2094 //
2095 Parameters parameters;
2096 public Parameters Parameters {
2097 get { return parameters; }
2098 }
2099
2100 public void RegisterCaptureContext (CaptureContext cc)
2101 {
2102 if (capture_contexts == null)
2103 capture_contexts = new Hashtable ();
2104 capture_contexts [cc] = cc;
2105 }
2106
2107 public void CompleteContexts ()
2108 {
2109 if (capture_contexts == null)
2110 return;
2111
2112 foreach (CaptureContext cc in capture_contexts.Keys){
2113 cc.LinkScopes ();
2114 }
2115 }
2116
2117 public CaptureContext ToplevelBlockCaptureContext {
2118 get { return capture_context; }
2119 }
2120
2121 public ToplevelBlock Container {
2122 get { return container; }
2123 }
2124
2125 protected void AddChild (ToplevelBlock block)
2126 {
2127 if (children == null)
2128 children = new ArrayList ();
2129
2130 children.Add (block);
2131 }
2132
2133 //
2134 // Parent is only used by anonymous blocks to link back to their
2135 // parents
2136 //
2137 public ToplevelBlock (ToplevelBlock container, Parameters parameters, Location start) :
2138 this (container, (Flags) 0, parameters, start)
2139 {
2140 }
2141
2142 public ToplevelBlock (Parameters parameters, Location start) :
2143 this (null, (Flags) 0, parameters, start)
2144 {
2145 }
2146
2147 public ToplevelBlock (Flags flags, Parameters parameters, Location start) :
2148 this (null, flags, parameters, start)
2149 {
2150 }
2151
2152 public ToplevelBlock (ToplevelBlock container, Flags flags, Parameters parameters, Location start) :
2153 base (null, flags | Flags.IsToplevel, start, Location.Null)
2154 {
2155 this.parameters = parameters == null ? Parameters.EmptyReadOnlyParameters : parameters;
2156 this.container = container;
2157
2158 if (container != null)
2159 container.AddChild (this);
2160 }
2161
2162 public ToplevelBlock (Location loc) : this (null, (Flags) 0, null, loc)
2163 {
2164 }
2165
2166 public void SetHaveAnonymousMethods (Location loc, AnonymousContainer host)
2167 {
2168 if (capture_context == null)
2169 capture_context = new CaptureContext (this, loc, host);
2170 }
2171
2172 public CaptureContext CaptureContext {
2173 get { return capture_context; }
2174 }
2175
2176 public FlowBranching TopLevelBranching {
2177 get { return top_level_branching; }
2178 }
2179
2180 //
2181 // This is used if anonymous methods are used inside an iterator
2182 // (see 2test-22.cs for an example).
2183 //
2184 // The AnonymousMethod is created while parsing - at a time when we don't
2185 // know yet that we're inside an iterator, so it's `Container' is initially
2186 // null. Later on, when resolving the iterator, we need to move the
2187 // anonymous method into that iterator.
2188 //
2189 public void ReParent (ToplevelBlock new_parent, AnonymousContainer new_host)
2190 {
2191 foreach (ToplevelBlock block in children) {
2192 if (block.CaptureContext == null)
2193 continue;
2194
2195 block.container = new_parent;
2196 block.CaptureContext.ReParent (new_parent, new_host);
2197 }
2198 }
2199
2200 //
2201 // Returns a `ParameterReference' for the given name, or null if there
2202 // is no such parameter
2203 //
2204 public ParameterReference GetParameterReference (string name, Location loc)
2205 {
2206 Parameter par;
2207 int idx;
2208
2209 for (ToplevelBlock t = this; t != null; t = t.Container) {
2210 Parameters pars = t.Parameters;
2211 par = pars.GetParameterByName (name, out idx);
2212 if (par != null)
2213 return new ParameterReference (par, this, idx, loc);
2214 }
2215 return null;
2216 }
2217
2218 //
2219 // Whether the parameter named `name' is local to this block,
2220 // or false, if the parameter belongs to an encompassing block.
2221 //
2222 public bool IsLocalParameter (string name)
2223 {
2224 return Parameters.GetParameterByName (name) != null;
2225 }
2226
2227 //
2228 // Whether the `name' is a parameter reference
2229 //
2230 public bool IsParameterReference (string name)
2231 {
2232 for (ToplevelBlock t = this; t != null; t = t.Container) {
2233 if (t.IsLocalParameter (name))
2234 return true;
2235 }
2236 return false;
2237 }
2238
2239 LocalInfo this_variable = null;
2240
2241 // <summary>
2242 // Returns the "this" instance variable of this block.
2243 // See AddThisVariable() for more information.
2244 // </summary>
2245 public LocalInfo ThisVariable {
2246 get { return this_variable; }
2247 }
2248
2249
2250 // <summary>
2251 // This is used by non-static `struct' constructors which do not have an
2252 // initializer - in this case, the constructor must initialize all of the
2253 // struct's fields. To do this, we add a "this" variable and use the flow
2254 // analysis code to ensure that it's been fully initialized before control
2255 // leaves the constructor.
2256 // </summary>
2257 public LocalInfo AddThisVariable (DeclSpace ds, Location l)
2258 {
2259 if (this_variable == null) {
2260 this_variable = new LocalInfo (ds, this, l);
2261 this_variable.Used = true;
2262 this_variable.IsThis = true;
2263
2264 Variables.Add ("this", this_variable);
2265 }
2266
2267 return this_variable;
2268 }
2269
2270 public bool IsThisAssigned (EmitContext ec)
2271 {
2272 return this_variable == null || this_variable.IsThisAssigned (ec, loc);
2273 }
2274
2275 public bool ResolveMeta (EmitContext ec, Parameters ip)
2276 {
2277 int errors = Report.Errors;
2278
2279 if (top_level_branching != null)
2280 return true;
2281
2282 if (ip != null)
2283 parameters = ip;
2284
2285 ResolveMeta (this, ec, ip);
2286
2287 top_level_branching = ec.StartFlowBranching (this);
2288
2289 return Report.Errors == errors;
2290 }
2291 }
2292
2293 public class SwitchLabel {
2294 Expression label;
2295 object converted;
2296 Location loc;
2297
2298 Label il_label;
2299 bool il_label_set;
2300 Label il_label_code;
2301 bool il_label_code_set;
2302
2303 public static readonly object NullStringCase = new object ();
2304
2305 //
2306 // if expr == null, then it is the default case.
2307 //
2308 public SwitchLabel (Expression expr, Location l)
2309 {
2310 label = expr;
2311 loc = l;
2312 }
2313
2314 public Expression Label {
2315 get {
2316 return label;
2317 }
2318 }
2319
2320 public object Converted {
2321 get {
2322 return converted;
2323 }
2324 }
2325
2326 public Label GetILLabel (EmitContext ec)
2327 {
2328 if (!il_label_set){
2329 il_label = ec.ig.DefineLabel ();
2330 il_label_set = true;
2331 }
2332 return il_label;
2333 }
2334
2335 public Label GetILLabelCode (EmitContext ec)
2336 {
2337 if (!il_label_code_set){
2338 il_label_code = ec.ig.DefineLabel ();
2339 il_label_code_set = true;
2340 }
2341 return il_label_code;
2342 }
2343
2344 //
2345 // Resolves the expression, reduces it to a literal if possible
2346 // and then converts it to the requested type.
2347 //
2348 public bool ResolveAndReduce (EmitContext ec, Type required_type)
2349 {
2350 Expression e = label.Resolve (ec);
2351
2352 if (e == null)
2353 return false;
2354
2355 Constant c = e as Constant;
2356 if (c == null){
2357 Report.Error (150, loc, "A constant value is expected");
2358 return false;
2359 }
2360
2361 if (required_type == TypeManager.string_type && c.GetValue () == null) {
2362 converted = NullStringCase;
2363 return true;
2364 }
2365
2366 c = c.ToType (required_type, loc);
2367 if (c == null)
2368 return false;
2369
2370 converted = c.GetValue ();
2371 return true;
2372 }
2373
2374 public void Erorr_AlreadyOccurs ()
2375 {
2376 string label;
2377 if (converted == null)
2378 label = "default";
2379 else if (converted == NullStringCase)
2380 label = "null";
2381 else
2382 label = converted.ToString ();
2383
2384 Report.Error (152, loc, "The label `case {0}:' already occurs in this switch statement", label);
2385 }
2386 }
2387
2388 public class SwitchSection {
2389 // An array of SwitchLabels.
2390 public readonly ArrayList Labels;
2391 public readonly Block Block;
2392
2393 public SwitchSection (ArrayList labels, Block block)
2394 {
2395 Labels = labels;
2396 Block = block;
2397 }
2398 }
2399
2400 public class Switch : Statement {
2401 public readonly ArrayList Sections;
2402 public Expression Expr;
2403
2404 /// <summary>
2405 /// Maps constants whose type type SwitchType to their SwitchLabels.
2406 /// </summary>
2407 public IDictionary Elements;
2408
2409 /// <summary>
2410 /// The governing switch type
2411 /// </summary>
2412 public Type SwitchType;
2413
2414 //
2415 // Computed
2416 //
2417 Label default_target;
2418 Expression new_expr;
2419 bool is_constant;
2420 SwitchSection constant_section;
2421 SwitchSection default_section;
2422
2423 //
2424 // The types allowed to be implicitly cast from
2425 // on the governing type
2426 //
2427 static Type [] allowed_types;
2428
2429 public Switch (Expression e, ArrayList sects, Location l)
2430 {
2431 Expr = e;
2432 Sections = sects;
2433 loc = l;
2434 }
2435
2436 public bool GotDefault {
2437 get {
2438 return default_section != null;
2439 }
2440 }
2441
2442 public Label DefaultTarget {
2443 get {
2444 return default_target;
2445 }
2446 }
2447
2448 //
2449 // Determines the governing type for a switch. The returned
2450 // expression might be the expression from the switch, or an
2451 // expression that includes any potential conversions to the
2452 // integral types or to string.
2453 //
2454 Expression SwitchGoverningType (EmitContext ec, Type t)
2455 {
2456 if (t == TypeManager.byte_type ||
2457 t == TypeManager.sbyte_type ||
2458 t == TypeManager.ushort_type ||
2459 t == TypeManager.short_type ||
2460 t == TypeManager.uint32_type ||
2461 t == TypeManager.int32_type ||
2462 t == TypeManager.uint64_type ||
2463 t == TypeManager.int64_type ||
2464 t == TypeManager.char_type ||
2465 t == TypeManager.string_type ||
2466 t == TypeManager.bool_type ||
2467 t.IsSubclassOf (TypeManager.enum_type))
2468 return Expr;
2469
2470 if (allowed_types == null){
2471 allowed_types = new Type [] {
2472 TypeManager.sbyte_type,
2473 TypeManager.byte_type,
2474 TypeManager.short_type,
2475 TypeManager.ushort_type,
2476 TypeManager.int32_type,
2477 TypeManager.uint32_type,
2478 TypeManager.int64_type,
2479 TypeManager.uint64_type,
2480 TypeManager.char_type,
2481 TypeManager.string_type,
2482 TypeManager.bool_type
2483 };
2484 }
2485
2486 //
2487 // Try to find a *user* defined implicit conversion.
2488 //
2489 // If there is no implicit conversion, or if there are multiple
2490 // conversions, we have to report an error
2491 //
2492 Expression converted = null;
2493 foreach (Type tt in allowed_types){
2494 Expression e;
2495
2496 e = Convert.ImplicitUserConversion (ec, Expr, tt, loc);
2497 if (e == null)
2498 continue;
2499
2500 //
2501 // Ignore over-worked ImplicitUserConversions that do
2502 // an implicit conversion in addition to the user conversion.
2503 //
2504 if (!(e is UserCast))
2505 continue;
2506
2507 if (converted != null){
2508 Report.ExtraInformation (
2509 loc,
2510 String.Format ("reason: more than one conversion to an integral type exist for type {0}",
2511 TypeManager.CSharpName (Expr.Type)));
2512 return null;
2513 }
2514
2515 converted = e;
2516 }
2517 return converted;
2518 }
2519
2520 //
2521 // Performs the basic sanity checks on the switch statement
2522 // (looks for duplicate keys and non-constant expressions).
2523 //
2524 // It also returns a hashtable with the keys that we will later
2525 // use to compute the switch tables
2526 //
2527 bool CheckSwitch (EmitContext ec)
2528 {
2529 bool error = false;
2530 Elements = Sections.Count > 10 ?
2531 (IDictionary)new Hashtable () :
2532 (IDictionary)new ListDictionary ();
2533
2534 foreach (SwitchSection ss in Sections){
2535 foreach (SwitchLabel sl in ss.Labels){
2536 if (sl.Label == null){
2537 if (default_section != null){
2538 sl.Erorr_AlreadyOccurs ();
2539 error = true;
2540 }
2541 default_section = ss;
2542 continue;
2543 }
2544
2545 if (!sl.ResolveAndReduce (ec, SwitchType)){
2546 error = true;
2547 continue;
2548 }
2549
2550 object key = sl.Converted;
2551 try {
2552 Elements.Add (key, sl);
2553 }
2554 catch (ArgumentException) {
2555 sl.Erorr_AlreadyOccurs ();
2556 error = true;
2557 }
2558 }
2559 }
2560 return !error;
2561 }
2562
2563 void EmitObjectInteger (ILGenerator ig, object k)
2564 {
2565 if (k is int)
2566 IntConstant.EmitInt (ig, (int) k);
2567 else if (k is Constant) {
2568 EmitObjectInteger (ig, ((Constant) k).GetValue ());
2569 }
2570 else if (k is uint)
2571 IntConstant.EmitInt (ig, unchecked ((int) (uint) k));
2572 else if (k is long)
2573 {
2574 if ((long) k >= int.MinValue && (long) k <= int.MaxValue)
2575 {
2576 IntConstant.EmitInt (ig, (int) (long) k);
2577 ig.Emit (OpCodes.Conv_I8);
2578 }
2579 else
2580 LongConstant.EmitLong (ig, (long) k);
2581 }
2582 else if (k is ulong)
2583 {
2584 ulong ul = (ulong) k;
2585 if (ul < (1L<<32))
2586 {
2587 IntConstant.EmitInt (ig, unchecked ((int) ul));
2588 ig.Emit (OpCodes.Conv_U8);
2589 }
2590 else
2591 {
2592 LongConstant.EmitLong (ig, unchecked ((long) ul));
2593 }
2594 }
2595 else if (k is char)
2596 IntConstant.EmitInt (ig, (int) ((char) k));
2597 else if (k is sbyte)
2598 IntConstant.EmitInt (ig, (int) ((sbyte) k));
2599 else if (k is byte)
2600 IntConstant.EmitInt (ig, (int) ((byte) k));
2601 else if (k is short)
2602 IntConstant.EmitInt (ig, (int) ((short) k));
2603 else if (k is ushort)
2604 IntConstant.EmitInt (ig, (int) ((ushort) k));
2605 else if (k is bool)
2606 IntConstant.EmitInt (ig, ((bool) k) ? 1 : 0);
2607 else
2608 throw new Exception ("Unhandled case");
2609 }
2610
2611 // structure used to hold blocks of keys while calculating table switch
2612 class KeyBlock : IComparable
2613 {
2614 public KeyBlock (long _nFirst)
2615 {
2616 nFirst = nLast = _nFirst;
2617 }
2618 public long nFirst;
2619 public long nLast;
2620 public ArrayList rgKeys = null;
2621 // how many items are in the bucket
2622 public int Size = 1;
2623 public int Length
2624 {
2625 get { return (int) (nLast - nFirst + 1); }
2626 }
2627 public static long TotalLength (KeyBlock kbFirst, KeyBlock kbLast)
2628 {
2629 return kbLast.nLast - kbFirst.nFirst + 1;
2630 }
2631 public int CompareTo (object obj)
2632 {
2633 KeyBlock kb = (KeyBlock) obj;
2634 int nLength = Length;
2635 int nLengthOther = kb.Length;
2636 if (nLengthOther == nLength)
2637 return (int) (kb.nFirst - nFirst);
2638 return nLength - nLengthOther;
2639 }
2640 }
2641
2642 /// <summary>
2643 /// This method emits code for a lookup-based switch statement (non-string)
2644 /// Basically it groups the cases into blocks that are at least half full,
2645 /// and then spits out individual lookup opcodes for each block.
2646 /// It emits the longest blocks first, and short blocks are just
2647 /// handled with direct compares.
2648 /// </summary>
2649 /// <param name="ec"></param>
2650 /// <param name="val"></param>
2651 /// <returns></returns>
2652 void TableSwitchEmit (EmitContext ec, LocalBuilder val)
2653 {
2654 int cElements = Elements.Count;
2655 object [] rgKeys = new object [cElements];
2656 Elements.Keys.CopyTo (rgKeys, 0);
2657 Array.Sort (rgKeys);
2658
2659 // initialize the block list with one element per key
2660 ArrayList rgKeyBlocks = new ArrayList ();
2661 foreach (object key in rgKeys)
2662 rgKeyBlocks.Add (new KeyBlock (System.Convert.ToInt64 (key)));
2663
2664 KeyBlock kbCurr;
2665 // iteratively merge the blocks while they are at least half full
2666 // there's probably a really cool way to do this with a tree...
2667 while (rgKeyBlocks.Count > 1)
2668 {
2669 ArrayList rgKeyBlocksNew = new ArrayList ();
2670 kbCurr = (KeyBlock) rgKeyBlocks [0];
2671 for (int ikb = 1; ikb < rgKeyBlocks.Count; ikb++)
2672 {
2673 KeyBlock kb = (KeyBlock) rgKeyBlocks [ikb];
2674 if ((kbCurr.Size + kb.Size) * 2 >= KeyBlock.TotalLength (kbCurr, kb))
2675 {
2676 // merge blocks
2677 kbCurr.nLast = kb.nLast;
2678 kbCurr.Size += kb.Size;
2679 }
2680 else
2681 {
2682 // start a new block
2683 rgKeyBlocksNew.Add (kbCurr);
2684 kbCurr = kb;
2685 }
2686 }
2687 rgKeyBlocksNew.Add (kbCurr);
2688 if (rgKeyBlocks.Count == rgKeyBlocksNew.Count)
2689 break;
2690 rgKeyBlocks = rgKeyBlocksNew;
2691 }
2692
2693 // initialize the key lists
2694 foreach (KeyBlock kb in rgKeyBlocks)
2695 kb.rgKeys = new ArrayList ();
2696
2697 // fill the key lists
2698 int iBlockCurr = 0;
2699 if (rgKeyBlocks.Count > 0) {
2700 kbCurr = (KeyBlock) rgKeyBlocks [0];
2701 foreach (object key in rgKeys)
2702 {
2703 bool fNextBlock = (key is UInt64) ? (ulong) key > (ulong) kbCurr.nLast :
2704 System.Convert.ToInt64 (key) > kbCurr.nLast;
2705 if (fNextBlock)
2706 kbCurr = (KeyBlock) rgKeyBlocks [++iBlockCurr];
2707 kbCurr.rgKeys.Add (key);
2708 }
2709 }
2710
2711 // sort the blocks so we can tackle the largest ones first
2712 rgKeyBlocks.Sort ();
2713
2714 // okay now we can start...
2715 ILGenerator ig = ec.ig;
2716 Label lblEnd = ig.DefineLabel (); // at the end ;-)
2717 Label lblDefault = ig.DefineLabel ();
2718
2719 Type typeKeys = null;
2720 if (rgKeys.Length > 0)
2721 typeKeys = rgKeys [0].GetType (); // used for conversions
2722
2723 Type compare_type;
2724
2725 if (TypeManager.IsEnumType (SwitchType))
2726 compare_type = TypeManager.EnumToUnderlying (SwitchType);
2727 else
2728 compare_type = SwitchType;
2729
2730 for (int iBlock = rgKeyBlocks.Count - 1; iBlock >= 0; --iBlock)
2731 {
2732 KeyBlock kb = ((KeyBlock) rgKeyBlocks [iBlock]);
2733 lblDefault = (iBlock == 0) ? DefaultTarget : ig.DefineLabel ();
2734 if (kb.Length <= 2)
2735 {
2736 foreach (object key in kb.rgKeys)
2737 {
2738 ig.Emit (OpCodes.Ldloc, val);
2739 EmitObjectInteger (ig, key);
2740 SwitchLabel sl = (SwitchLabel) Elements [key];
2741 ig.Emit (OpCodes.Beq, sl.GetILLabel (ec));
2742 }
2743 }
2744 else
2745 {
2746 // TODO: if all the keys in the block are the same and there are
2747 // no gaps/defaults then just use a range-check.
2748 if (compare_type == TypeManager.int64_type ||
2749 compare_type == TypeManager.uint64_type)
2750 {
2751 // TODO: optimize constant/I4 cases
2752
2753 // check block range (could be > 2^31)
2754 ig.Emit (OpCodes.Ldloc, val);
2755 EmitObjectInteger (ig, System.Convert.ChangeType (kb.nFirst, typeKeys));
2756 ig.Emit (OpCodes.Blt, lblDefault);
2757 ig.Emit (OpCodes.Ldloc, val);
2758 EmitObjectInteger (ig, System.Convert.ChangeType (kb.nLast, typeKeys));
2759 ig.Emit (OpCodes.Bgt, lblDefault);
2760
2761 // normalize range
2762 ig.Emit (OpCodes.Ldloc, val);
2763 if (kb.nFirst != 0)
2764 {
2765 EmitObjectInteger (ig, System.Convert.ChangeType (kb.nFirst, typeKeys));
2766 ig.Emit (OpCodes.Sub);
2767 }
2768 ig.Emit (OpCodes.Conv_I4); // assumes < 2^31 labels!
2769 }
2770 else
2771 {
2772 // normalize range
2773 ig.Emit (OpCodes.Ldloc, val);
2774 int nFirst = (int) kb.nFirst;
2775 if (nFirst > 0)
2776 {
2777 IntConstant.EmitInt (ig, nFirst);
2778 ig.Emit (OpCodes.Sub);
2779 }
2780 else if (nFirst < 0)
2781 {
2782 IntConstant.EmitInt (ig, -nFirst);
2783 ig.Emit (OpCodes.Add);
2784 }
2785 }
2786
2787 // first, build the list of labels for the switch
2788 int iKey = 0;
2789 int cJumps = kb.Length;
2790 Label [] rgLabels = new Label [cJumps];
2791 for (int iJump = 0; iJump < cJumps; iJump++)
2792 {
2793 object key = kb.rgKeys [iKey];
2794 if (System.Convert.ToInt64 (key) == kb.nFirst + iJump)
2795 {
2796 SwitchLabel sl = (SwitchLabel) Elements [key];
2797 rgLabels [iJump] = sl.GetILLabel (ec);
2798 iKey++;
2799 }
2800 else
2801 rgLabels [iJump] = lblDefault;
2802 }
2803 // emit the switch opcode
2804 ig.Emit (OpCodes.Switch, rgLabels);
2805 }
2806
2807 // mark the default for this block
2808 if (iBlock != 0)
2809 ig.MarkLabel (lblDefault);
2810 }
2811
2812 // TODO: find the default case and emit it here,
2813 // to prevent having to do the following jump.
2814 // make sure to mark other labels in the default section
2815
2816 // the last default just goes to the end
2817 ig.Emit (OpCodes.Br, lblDefault);
2818
2819 // now emit the code for the sections
2820 bool fFoundDefault = false;
2821 foreach (SwitchSection ss in Sections)
2822 {
2823 foreach (SwitchLabel sl in ss.Labels)
2824 {
2825 ig.MarkLabel (sl.GetILLabel (ec));
2826 ig.MarkLabel (sl.GetILLabelCode (ec));
2827 if (sl.Label == null)
2828 {
2829 ig.MarkLabel (lblDefault);
2830 fFoundDefault = true;
2831 }
2832 }
2833 ss.Block.Emit (ec);
2834 //ig.Emit (OpCodes.Br, lblEnd);
2835 }
2836
2837 if (!fFoundDefault) {
2838 ig.MarkLabel (lblDefault);
2839 }
2840 ig.MarkLabel (lblEnd);
2841 }
2842 //
2843 // This simple emit switch works, but does not take advantage of the
2844 // `switch' opcode.
2845 // TODO: remove non-string logic from here
2846 // TODO: binary search strings?
2847 //
2848 void SimpleSwitchEmit (EmitContext ec, LocalBuilder val)
2849 {
2850 ILGenerator ig = ec.ig;
2851 Label end_of_switch = ig.DefineLabel ();
2852 Label next_test = ig.DefineLabel ();
2853 Label null_target = ig.DefineLabel ();
2854 bool first_test = true;
2855 bool pending_goto_end = false;
2856 bool null_marked = false;
2857 bool null_found;
2858
2859 ig.Emit (OpCodes.Ldloc, val);
2860
2861 if (Elements.Contains (SwitchLabel.NullStringCase)){
2862 ig.Emit (OpCodes.Brfalse, null_target);
2863 } else
2864 ig.Emit (OpCodes.Brfalse, default_target);
2865
2866 ig.Emit (OpCodes.Ldloc, val);
2867 ig.Emit (OpCodes.Call, TypeManager.string_isinterneted_string);
2868 ig.Emit (OpCodes.Stloc, val);
2869
2870 int section_count = Sections.Count;
2871 for (int section = 0; section < section_count; section++){
2872 SwitchSection ss = (SwitchSection) Sections [section];
2873
2874 if (ss == default_section)
2875 continue;
2876
2877 Label sec_begin = ig.DefineLabel ();
2878
2879 ig.Emit (OpCodes.Nop);
2880
2881 if (pending_goto_end)
2882 ig.Emit (OpCodes.Br, end_of_switch);
2883
2884 int label_count = ss.Labels.Count;
2885 null_found = false;
2886 for (int label = 0; label < label_count; label++){
2887 SwitchLabel sl = (SwitchLabel) ss.Labels [label];
2888 ig.MarkLabel (sl.GetILLabel (ec));
2889
2890 if (!first_test){
2891 ig.MarkLabel (next_test);
2892 next_test = ig.DefineLabel ();
2893 }
2894 //
2895 // If we are the default target
2896 //
2897 if (sl.Label != null){
2898 object lit = sl.Converted;
2899
2900 if (lit == SwitchLabel.NullStringCase){
2901 null_found = true;
2902 if (label_count == 1)
2903 ig.Emit (OpCodes.Br, next_test);
2904 continue;
2905 }
2906
2907 ig.Emit (OpCodes.Ldloc, val);
2908 ig.Emit (OpCodes.Ldstr, (string)lit);
2909 if (label_count == 1)
2910 ig.Emit (OpCodes.Bne_Un, next_test);
2911 else {
2912 if (label+1 == label_count)
2913 ig.Emit (OpCodes.Bne_Un, next_test);
2914 else
2915 ig.Emit (OpCodes.Beq, sec_begin);
2916 }
2917 }
2918 }
2919 if (null_found) {
2920 ig.MarkLabel (null_target);
2921 null_marked = true;
2922 }
2923 ig.MarkLabel (sec_begin);
2924 foreach (SwitchLabel sl in ss.Labels)
2925 ig.MarkLabel (sl.GetILLabelCode (ec));
2926
2927 ss.Block.Emit (ec);
2928 pending_goto_end = !ss.Block.HasRet;
2929 first_test = false;
2930 }
2931 ig.MarkLabel (next_test);
2932 ig.MarkLabel (default_target);
2933 if (!null_marked)
2934 ig.MarkLabel (null_target);
2935 if (default_section != null)
2936 default_section.Block.Emit (ec);
2937 ig.MarkLabel (end_of_switch);
2938 }
2939
2940 SwitchSection FindSection (SwitchLabel label)
2941 {
2942 foreach (SwitchSection ss in Sections){
2943 foreach (SwitchLabel sl in ss.Labels){
2944 if (label == sl)
2945 return ss;
2946 }
2947 }
2948
2949 return null;
2950 }
2951
2952 public override bool Resolve (EmitContext ec)
2953 {
2954 Expr = Expr.Resolve (ec);
2955 if (Expr == null)
2956 return false;
2957
2958 new_expr = SwitchGoverningType (ec, Expr.Type);
2959 if (new_expr == null){
2960 Report.Error (151, loc, "A value of an integral type or string expected for switch");
2961 return false;
2962 }
2963
2964 // Validate switch.
2965 SwitchType = new_expr.Type;
2966
2967 if (!CheckSwitch (ec))
2968 return false;
2969
2970 Switch old_switch = ec.Switch;
2971 ec.Switch = this;
2972 ec.Switch.SwitchType = SwitchType;
2973
2974 Report.Debug (1, "START OF SWITCH BLOCK", loc, ec.CurrentBranching);
2975 ec.StartFlowBranching (FlowBranching.BranchingType.Switch, loc);
2976
2977 is_constant = new_expr is Constant;
2978 if (is_constant) {
2979 object key = ((Constant) new_expr).GetValue ();
2980 SwitchLabel label = (SwitchLabel) Elements [key];
2981
2982 constant_section = FindSection (label);
2983 if (constant_section == null)
2984 constant_section = default_section;
2985 }
2986
2987 bool first = true;
2988 foreach (SwitchSection ss in Sections){
2989 if (!first)
2990 ec.CurrentBranching.CreateSibling (
2991 null, FlowBranching.SiblingType.SwitchSection);
2992 else
2993 first = false;
2994
2995 if (is_constant && (ss != constant_section)) {
2996 // If we're a constant switch, we're only emitting
2997 // one single section - mark all the others as
2998 // unreachable.
2999 ec.CurrentBranching.CurrentUsageVector.Goto ();
3000 if (!ss.Block.ResolveUnreachable (ec, true))
3001 return false;
3002 } else {
3003 if (!ss.Block.Resolve (ec))
3004 return false;
3005 }
3006 }
3007
3008 if (default_section == null)
3009 ec.CurrentBranching.CreateSibling (
3010 null, FlowBranching.SiblingType.SwitchSection);
3011
3012 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
3013 ec.Switch = old_switch;
3014
3015 Report.Debug (1, "END OF SWITCH BLOCK", loc, ec.CurrentBranching,
3016 reachability);
3017
3018 return true;
3019 }
3020
3021 protected override void DoEmit (EmitContext ec)
3022 {
3023 ILGenerator ig = ec.ig;
3024
3025 // Store variable for comparission purposes
3026 LocalBuilder value;
3027 if (!is_constant) {
3028 value = ig.DeclareLocal (SwitchType);
3029 new_expr.Emit (ec);
3030 ig.Emit (OpCodes.Stloc, value);
3031 } else
3032 value = null;
3033
3034 default_target = ig.DefineLabel ();
3035
3036 //
3037 // Setup the codegen context
3038 //
3039 Label old_end = ec.LoopEnd;
3040 Switch old_switch = ec.Switch;
3041
3042 ec.LoopEnd = ig.DefineLabel ();
3043 ec.Switch = this;
3044
3045 // Emit Code.
3046 if (is_constant) {
3047 if (constant_section != null)
3048 constant_section.Block.Emit (ec);
3049 } else if (SwitchType == TypeManager.string_type)
3050 SimpleSwitchEmit (ec, value);
3051 else
3052 TableSwitchEmit (ec, value);
3053
3054 // Restore context state.
3055 ig.MarkLabel (ec.LoopEnd);
3056
3057 //
3058 // Restore the previous context
3059 //
3060 ec.LoopEnd = old_end;
3061 ec.Switch = old_switch;
3062 }
3063 }
3064
3065 public abstract class ExceptionStatement : Statement
3066 {
3067 public abstract void EmitFinally (EmitContext ec);
3068
3069 protected bool emit_finally = true;
3070 ArrayList parent_vectors;
3071
3072 protected void DoEmitFinally (EmitContext ec)
3073 {
3074 if (emit_finally)
3075 ec.ig.BeginFinallyBlock ();
3076 else if (ec.InIterator)
3077 ec.CurrentIterator.MarkFinally (ec, parent_vectors);
3078 EmitFinally (ec);
3079 }
3080
3081 protected void ResolveFinally (FlowBranchingException branching)
3082 {
3083 emit_finally = branching.EmitFinally;
3084 if (!emit_finally)
3085 branching.Parent.StealFinallyClauses (ref parent_vectors);
3086 }
3087 }
3088
3089 public class Lock : ExceptionStatement {
3090 Expression expr;
3091 public Statement Statement;
3092 TemporaryVariable temp;
3093
3094 public Lock (Expression expr, Statement stmt, Location l)
3095 {
3096 this.expr = expr;
3097 Statement = stmt;
3098 loc = l;
3099 }
3100
3101 public override bool Resolve (EmitContext ec)
3102 {
3103 expr = expr.Resolve (ec);
3104 if (expr == null)
3105 return false;
3106
3107 if (expr.Type.IsValueType){
3108 Report.Error (185, loc,
3109 "`{0}' is not a reference type as required by the lock statement",
3110 TypeManager.CSharpName (expr.Type));
3111 return false;
3112 }
3113
3114 FlowBranchingException branching = ec.StartFlowBranching (this);
3115 bool ok = Statement.Resolve (ec);
3116 if (!ok) {
3117 ec.KillFlowBranching ();
3118 return false;
3119 }
3120
3121 ResolveFinally (branching);
3122
3123 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
3124 if (reachability.Returns != FlowBranching.FlowReturns.Always) {
3125 // Unfortunately, System.Reflection.Emit automatically emits
3126 // a leave to the end of the finally block.
3127 // This is a problem if `returns' is true since we may jump
3128 // to a point after the end of the method.
3129 // As a workaround, emit an explicit ret here.
3130 ec.NeedReturnLabel ();
3131 }
3132
3133 temp = new TemporaryVariable (expr.Type, loc);
3134 temp.Resolve (ec);
3135
3136 return true;
3137 }
3138
3139 protected override void DoEmit (EmitContext ec)
3140 {
3141 ILGenerator ig = ec.ig;
3142
3143 temp.Store (ec, expr);
3144 temp.Emit (ec);
3145 ig.Emit (OpCodes.Call, TypeManager.void_monitor_enter_object);
3146
3147 // try
3148 if (emit_finally)
3149 ig.BeginExceptionBlock ();
3150 Statement.Emit (ec);
3151
3152 // finally
3153 DoEmitFinally (ec);
3154 if (emit_finally)
3155 ig.EndExceptionBlock ();
3156 }
3157
3158 public override void EmitFinally (EmitContext ec)
3159 {
3160 temp.Emit (ec);
3161 ec.ig.Emit (OpCodes.Call, TypeManager.void_monitor_exit_object);
3162 }
3163 }
3164
3165 public class Unchecked : Statement {
3166 public readonly Block Block;
3167
3168 public Unchecked (Block b)
3169 {
3170 Block = b;
3171 b.Unchecked = true;
3172 }
3173
3174 public override bool Resolve (EmitContext ec)
3175 {
3176 bool previous_state = ec.CheckState;
3177 bool previous_state_const = ec.ConstantCheckState;
3178
3179 ec.CheckState = false;
3180 ec.ConstantCheckState = false;
3181 bool ret = Block.Resolve (ec);
3182 ec.CheckState = previous_state;
3183 ec.ConstantCheckState = previous_state_const;
3184
3185 return ret;
3186 }
3187
3188 protected override void DoEmit (EmitContext ec)
3189 {
3190 bool previous_state = ec.CheckState;
3191 bool previous_state_const = ec.ConstantCheckState;
3192
3193 ec.CheckState = false;
3194 ec.ConstantCheckState = false;
3195 Block.Emit (ec);
3196 ec.CheckState = previous_state;
3197 ec.ConstantCheckState = previous_state_const;
3198 }
3199 }
3200
3201 public class Checked : Statement {
3202 public readonly Block Block;
3203
3204 public Checked (Block b)
3205 {
3206 Block = b;
3207 b.Unchecked = false;
3208 }
3209
3210 public override bool Resolve (EmitContext ec)
3211 {
3212 bool previous_state = ec.CheckState;
3213 bool previous_state_const = ec.ConstantCheckState;
3214
3215 ec.CheckState = true;
3216 ec.ConstantCheckState = true;
3217 bool ret = Block.Resolve (ec);
3218 ec.CheckState = previous_state;
3219 ec.ConstantCheckState = previous_state_const;
3220
3221 return ret;
3222 }
3223
3224 protected override void DoEmit (EmitContext ec)
3225 {
3226 bool previous_state = ec.CheckState;
3227 bool previous_state_const = ec.ConstantCheckState;
3228
3229 ec.CheckState = true;
3230 ec.ConstantCheckState = true;
3231 Block.Emit (ec);
3232 ec.CheckState = previous_state;
3233 ec.ConstantCheckState = previous_state_const;
3234 }
3235 }
3236
3237 public class Unsafe : Statement {
3238 public readonly Block Block;
3239
3240 public Unsafe (Block b)
3241 {
3242 Block = b;
3243 Block.Unsafe = true;
3244 }
3245
3246 public override bool Resolve (EmitContext ec)
3247 {
3248 bool previous_state = ec.InUnsafe;
3249 bool val;
3250
3251 ec.InUnsafe = true;
3252 val = Block.Resolve (ec);
3253 ec.InUnsafe = previous_state;
3254
3255 return val;
3256 }
3257
3258 protected override void DoEmit (EmitContext ec)
3259 {
3260 bool previous_state = ec.InUnsafe;
3261
3262 ec.InUnsafe = true;
3263 Block.Emit (ec);
3264 ec.InUnsafe = previous_state;
3265 }
3266 }
3267
3268 //
3269 // Fixed statement
3270 //
3271 public class Fixed : Statement {
3272 Expression type;
3273 ArrayList declarators;
3274 Statement statement;
3275 Type expr_type;
3276 Emitter[] data;
3277 bool has_ret;
3278
3279 abstract class Emitter
3280 {
3281 protected LocalInfo vi;
3282 protected Expression converted;
3283
3284 protected Emitter (Expression expr, LocalInfo li)
3285 {
3286 converted = expr;
3287 vi = li;
3288 }
3289
3290 public abstract void Emit (EmitContext ec);
3291 public abstract void EmitExit (ILGenerator ig);
3292 }
3293
3294 class ExpressionEmitter : Emitter {
3295 public ExpressionEmitter (Expression converted, LocalInfo li) :
3296 base (converted, li)
3297 {
3298 }
3299
3300 public override void Emit (EmitContext ec) {
3301 //
3302 // Store pointer in pinned location
3303 //
3304 converted.Emit (ec);
3305 ec.ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
3306 }
3307
3308 public override void EmitExit (ILGenerator ig)
3309 {
3310 ig.Emit (OpCodes.Ldc_I4_0);
3311 ig.Emit (OpCodes.Conv_U);
3312 ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
3313 }
3314 }
3315
3316 class StringEmitter : Emitter {
3317 LocalBuilder pinned_string;
3318 Location loc;
3319
3320 public StringEmitter (Expression expr, LocalInfo li, Location loc):
3321 base (expr, li)
3322 {
3323 this.loc = loc;
3324 }
3325
3326 public override void Emit (EmitContext ec)
3327 {
3328 ILGenerator ig = ec.ig;
3329 pinned_string = TypeManager.DeclareLocalPinned (ig, TypeManager.string_type);
3330
3331 converted.Emit (ec);
3332 ig.Emit (OpCodes.Stloc, pinned_string);
3333
3334 Expression sptr = new StringPtr (pinned_string, loc);
3335 converted = Convert.ImplicitConversionRequired (
3336 ec, sptr, vi.VariableType, loc);
3337
3338 if (converted == null)
3339 return;
3340
3341 converted.Emit (ec);
3342 ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
3343 }
3344
3345 public override void EmitExit(ILGenerator ig)
3346 {
3347 ig.Emit (OpCodes.Ldnull);
3348 ig.Emit (OpCodes.Stloc, pinned_string);
3349 }
3350 }
3351
3352 public Fixed (Expression type, ArrayList decls, Statement stmt, Location l)
3353 {
3354 this.type = type;
3355 declarators = decls;
3356 statement = stmt;
3357 loc = l;
3358 }
3359
3360 public Statement Statement {
3361 get { return statement; }
3362 }
3363
3364 public override bool Resolve (EmitContext ec)
3365 {
3366 if (!ec.InUnsafe){
3367 Expression.UnsafeError (loc);
3368 return false;
3369 }
3370
3371 TypeExpr texpr = type.ResolveAsTypeTerminal (ec, false);
3372 if (texpr == null)
3373 return false;
3374
3375 expr_type = texpr.Type;
3376
3377 data = new Emitter [declarators.Count];
3378
3379 if (!expr_type.IsPointer){
3380 Report.Error (209, loc, "The type of locals declared in a fixed statement must be a pointer type");
3381 return false;
3382 }
3383
3384 int i = 0;
3385 foreach (Pair p in declarators){
3386 LocalInfo vi = (LocalInfo) p.First;
3387 Expression e = (Expression) p.Second;
3388
3389 vi.VariableInfo.SetAssigned (ec);
3390 vi.SetReadOnlyContext (LocalInfo.ReadOnlyContext.Fixed);
3391
3392 //
3393 // The rules for the possible declarators are pretty wise,
3394 // but the production on the grammar is more concise.
3395 //
3396 // So we have to enforce these rules here.
3397 //
3398 // We do not resolve before doing the case 1 test,
3399 // because the grammar is explicit in that the token &
3400 // is present, so we need to test for this particular case.
3401 //
3402
3403 if (e is Cast){
3404 Report.Error (254, loc, "The right hand side of a fixed statement assignment may not be a cast expression");
3405 return false;
3406 }
3407
3408 //
3409 // Case 1: & object.
3410 //
3411 if (e is Unary && ((Unary) e).Oper == Unary.Operator.AddressOf){
3412 Expression child = ((Unary) e).Expr;
3413
3414 if (child is ParameterReference || child is LocalVariableReference){
3415 Report.Error (
3416 213, loc,
3417 "No need to use fixed statement for parameters or " +
3418 "local variable declarations (address is already " +
3419 "fixed)");
3420 return false;
3421 }
3422
3423 ec.InFixedInitializer = true;
3424 e = e.Resolve (ec);
3425 ec.InFixedInitializer = false;
3426 if (e == null)
3427 return false;
3428
3429 child = ((Unary) e).Expr;
3430
3431 if (!TypeManager.VerifyUnManaged (child.Type, loc))
3432 return false;
3433
3434 if (!Convert.ImplicitConversionExists (ec, e, expr_type)) {
3435 e.Error_ValueCannotBeConverted (e.Location, expr_type, false);
3436 return false;
3437 }
3438
3439 data [i] = new ExpressionEmitter (e, vi);
3440 i++;
3441
3442 continue;
3443 }
3444
3445 ec.InFixedInitializer = true;
3446 e = e.Resolve (ec);
3447 ec.InFixedInitializer = false;
3448 if (e == null)
3449 return false;
3450
3451 //
3452 // Case 2: Array
3453 //
3454 if (e.Type.IsArray){
3455 Type array_type = TypeManager.GetElementType (e.Type);
3456
3457 //
3458 // Provided that array_type is unmanaged,
3459 //
3460 if (!TypeManager.VerifyUnManaged (array_type, loc))
3461 return false;
3462
3463 //
3464 // and T* is implicitly convertible to the
3465 // pointer type given in the fixed statement.
3466 //
3467 ArrayPtr array_ptr = new ArrayPtr (e, array_type, loc);
3468
3469 Expression converted = Convert.ImplicitConversionRequired (
3470 ec, array_ptr, vi.VariableType, loc);
3471 if (converted == null)
3472 return false;
3473
3474 data [i] = new ExpressionEmitter (converted, vi);
3475 i++;
3476
3477 continue;
3478 }
3479
3480 //
3481 // Case 3: string
3482 //
3483 if (e.Type == TypeManager.string_type){
3484 data [i] = new StringEmitter (e, vi, loc);
3485 i++;
3486 continue;
3487 }
3488
3489 // Case 4: fixed buffer
3490 FieldExpr fe = e as FieldExpr;
3491 if (fe != null) {
3492 IFixedBuffer ff = AttributeTester.GetFixedBuffer (fe.FieldInfo);
3493 if (ff != null) {
3494 Expression fixed_buffer_ptr = new FixedBufferPtr (fe, ff.ElementType, loc);
3495
3496 Expression converted = Convert.ImplicitConversionRequired (
3497 ec, fixed_buffer_ptr, vi.VariableType, loc);
3498 if (converted == null)
3499 return false;
3500
3501 data [i] = new ExpressionEmitter (converted, vi);
3502 i++;
3503
3504 continue;
3505 }
3506 }
3507
3508 //
3509 // For other cases, flag a `this is already fixed expression'
3510 //
3511 if (e is LocalVariableReference || e is ParameterReference ||
3512 Convert.ImplicitConversionExists (ec, e, vi.VariableType)){
3513
3514 Report.Error (245, loc, "right hand expression is already fixed, no need to use fixed statement ");
3515 return false;
3516 }
3517
3518 Report.Error (245, loc, "Fixed statement only allowed on strings, arrays or address-of expressions");
3519 return false;
3520 }
3521
3522 ec.StartFlowBranching (FlowBranching.BranchingType.Conditional, loc);
3523
3524 if (!statement.Resolve (ec)) {
3525 ec.KillFlowBranching ();
3526 return false;
3527 }
3528
3529 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
3530 has_ret = reachability.IsUnreachable;
3531
3532 return true;
3533 }
3534
3535 protected override void DoEmit (EmitContext ec)
3536 {
3537 for (int i = 0; i < data.Length; i++) {
3538 data [i].Emit (ec);
3539 }
3540
3541 statement.Emit (ec);
3542
3543 if (has_ret)
3544 return;
3545
3546 ILGenerator ig = ec.ig;
3547
3548 //
3549 // Clear the pinned variable
3550 //
3551 for (int i = 0; i < data.Length; i++) {
3552 data [i].EmitExit (ig);
3553 }
3554 }
3555 }
3556
3557 public class Catch : Statement {
3558 public readonly string Name;
3559 public readonly Block Block;
3560 public readonly Block VarBlock;
3561
3562 Expression type_expr;
3563 Type type;
3564
3565 public Catch (Expression type, string name, Block block, Block var_block, Location l)
3566 {
3567 type_expr = type;
3568 Name = name;
3569 Block = block;
3570 VarBlock = var_block;
3571 loc = l;
3572 }
3573
3574 public Type CatchType {
3575 get {
3576 return type;
3577 }
3578 }
3579
3580 public bool IsGeneral {
3581 get {
3582 return type_expr == null;
3583 }
3584 }
3585
3586 protected override void DoEmit(EmitContext ec)
3587 {
3588 }
3589
3590 public override bool Resolve (EmitContext ec)
3591 {
3592 bool was_catch = ec.InCatch;
3593 ec.InCatch = true;
3594 try {
3595 if (type_expr != null) {
3596 TypeExpr te = type_expr.ResolveAsTypeTerminal (ec, false);
3597 if (te == null)
3598 return false;
3599
3600 type = te.Type;
3601
3602 if (type != TypeManager.exception_type && !type.IsSubclassOf (TypeManager.exception_type)){
3603 Error (155, "The type caught or thrown must be derived from System.Exception");
3604 return false;
3605 }
3606 } else
3607 type = null;
3608
3609 if (!Block.Resolve (ec))
3610 return false;
3611
3612 // Even though VarBlock surrounds 'Block' we resolve it later, so that we can correctly
3613 // emit the "unused variable" warnings.
3614 if (VarBlock != null)
3615 return VarBlock.Resolve (ec);
3616
3617 return true;
3618 }
3619 finally {
3620 ec.InCatch = was_catch;
3621 }
3622 }
3623 }
3624
3625 public class Try : ExceptionStatement {
3626 public readonly Block Fini, Block;
3627 public readonly ArrayList Specific;
3628 public readonly Catch General;
3629
3630 bool need_exc_block;
3631
3632 //
3633 // specific, general and fini might all be null.
3634 //
3635 public Try (Block block, ArrayList specific, Catch general, Block fini, Location l)
3636 {
3637 if (specific == null && general == null){
3638 Console.WriteLine ("CIR.Try: Either specific or general have to be non-null");
3639 }
3640
3641 this.Block = block;
3642 this.Specific = specific;
3643 this.General = general;
3644 this.Fini = fini;
3645 loc = l;
3646 }
3647
3648 public override bool Resolve (EmitContext ec)
3649 {
3650 bool ok = true;
3651
3652 FlowBranchingException branching = ec.StartFlowBranching (this);
3653
3654 Report.Debug (1, "START OF TRY BLOCK", Block.StartLocation);
3655
3656 if (!Block.Resolve (ec))
3657 ok = false;
3658
3659 FlowBranching.UsageVector vector = ec.CurrentBranching.CurrentUsageVector;
3660
3661 Report.Debug (1, "START OF CATCH BLOCKS", vector);
3662
3663 Type[] prevCatches = new Type [Specific.Count];
3664 int last_index = 0;
3665 foreach (Catch c in Specific){
3666 ec.CurrentBranching.CreateSibling (
3667 c.Block, FlowBranching.SiblingType.Catch);
3668
3669 Report.Debug (1, "STARTED SIBLING FOR CATCH", ec.CurrentBranching);
3670
3671 if (c.Name != null) {
3672 LocalInfo vi = c.Block.GetLocalInfo (c.Name);
3673 if (vi == null)
3674 throw new Exception ();
3675
3676 vi.VariableInfo = null;
3677 }
3678
3679 if (!c.Resolve (ec))
3680 return false;
3681
3682 Type resolvedType = c.CatchType;
3683 for (int ii = 0; ii < last_index; ++ii) {
3684 if (resolvedType == prevCatches [ii] || resolvedType.IsSubclassOf (prevCatches [ii])) {
3685 Report.Error (160, c.loc, "A previous catch clause already catches all exceptions of this or a super type `{0}'", prevCatches [ii].FullName);
3686 return false;
3687 }
3688 }
3689
3690 prevCatches [last_index++] = resolvedType;
3691 need_exc_block = true;
3692 }
3693
3694 Report.Debug (1, "END OF CATCH BLOCKS", ec.CurrentBranching);
3695
3696 if (General != null){
3697 if (CodeGen.Assembly.WrapNonExceptionThrows) {
3698 foreach (Catch c in Specific){
3699 if (c.CatchType == TypeManager.exception_type) {
3700 Report.Warning (1058, 1, c.loc, "A previous catch clause already catches all exceptions. All non-exceptions thrown will be wrapped in a `System.Runtime.CompilerServices.RuntimeWrappedException'");
3701 }
3702 }
3703 }
3704
3705 ec.CurrentBranching.CreateSibling (
3706 General.Block, FlowBranching.SiblingType.Catch);
3707
3708 Report.Debug (1, "STARTED SIBLING FOR GENERAL", ec.CurrentBranching);
3709
3710 if (!General.Resolve (ec))
3711 ok = false;
3712
3713 need_exc_block = true;
3714 }
3715
3716 Report.Debug (1, "END OF GENERAL CATCH BLOCKS", ec.CurrentBranching);
3717
3718 if (Fini != null) {
3719 if (ok)
3720 ec.CurrentBranching.CreateSibling (
3721 Fini, FlowBranching.SiblingType.Finally);
3722
3723 Report.Debug (1, "STARTED SIBLING FOR FINALLY", ec.CurrentBranching, vector);
3724 bool was_finally = ec.InFinally;
3725 ec.InFinally = true;
3726 if (!Fini.Resolve (ec))
3727 ok = false;
3728 ec.InFinally = was_finally;
3729
3730 if (!ec.InIterator)
3731 need_exc_block = true;
3732 }
3733
3734 if (ec.InIterator) {
3735 ResolveFinally (branching);
3736 need_exc_block |= emit_finally;
3737 } else
3738 emit_finally = Fini != null;
3739
3740 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
3741
3742 FlowBranching.UsageVector f_vector = ec.CurrentBranching.CurrentUsageVector;
3743
3744 Report.Debug (1, "END OF TRY", ec.CurrentBranching, reachability, vector, f_vector);
3745
3746 if (reachability.Returns != FlowBranching.FlowReturns.Always) {
3747 // Unfortunately, System.Reflection.Emit automatically emits
3748 // a leave to the end of the finally block. This is a problem
3749 // if `returns' is true since we may jump to a point after the
3750 // end of the method.
3751 // As a workaround, emit an explicit ret here.
3752 ec.NeedReturnLabel ();
3753 }
3754
3755 return ok;
3756 }
3757
3758 protected override void DoEmit (EmitContext ec)
3759 {
3760 ILGenerator ig = ec.ig;
3761
3762 if (need_exc_block)
3763 ig.BeginExceptionBlock ();
3764 Block.Emit (ec);
3765
3766 foreach (Catch c in Specific){
3767 LocalInfo vi;
3768
3769 ig.BeginCatchBlock (c.CatchType);
3770
3771 if (c.VarBlock != null)
3772 ec.EmitScopeInitFromBlock (c.VarBlock);
3773 if (c.Name != null){
3774 vi = c.Block.GetLocalInfo (c.Name);
3775 if (vi == null)
3776 throw new Exception ("Variable does not exist in this block");
3777
3778 if (vi.IsCaptured){
3779 LocalBuilder e = ig.DeclareLocal (vi.VariableType);
3780 ig.Emit (OpCodes.Stloc, e);
3781
3782 ec.EmitCapturedVariableInstance (vi);
3783 ig.Emit (OpCodes.Ldloc, e);
3784 ig.Emit (OpCodes.Stfld, vi.FieldBuilder);
3785 } else
3786 ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
3787 } else
3788 ig.Emit (OpCodes.Pop);
3789
3790 c.Block.Emit (ec);
3791 }
3792
3793 if (General != null){
3794 ig.BeginCatchBlock (TypeManager.object_type);
3795 ig.Emit (OpCodes.Pop);
3796 General.Block.Emit (ec);
3797 }
3798
3799 DoEmitFinally (ec);
3800 if (need_exc_block)
3801 ig.EndExceptionBlock ();
3802 }
3803
3804 public override void EmitFinally (EmitContext ec)
3805 {
3806 if (Fini != null)
3807 Fini.Emit (ec);
3808 }
3809
3810 public bool HasCatch
3811 {
3812 get {
3813 return General != null || Specific.Count > 0;
3814 }
3815 }
3816 }
3817
3818 public class Using : ExceptionStatement {
3819 object expression_or_block;
3820 public Statement Statement;
3821 ArrayList var_list;
3822 Expression expr;
3823 Type expr_type;
3824 Expression [] resolved_vars;
3825 Expression [] converted_vars;
3826 ExpressionStatement [] assign;
3827 LocalBuilder local_copy;
3828
3829 public Using (object expression_or_block, Statement stmt, Location l)
3830 {
3831 this.expression_or_block = expression_or_block;
3832 Statement = stmt;
3833 loc = l;
3834 }
3835
3836 //
3837 // Resolves for the case of using using a local variable declaration.
3838 //
3839 bool ResolveLocalVariableDecls (EmitContext ec)
3840 {
3841 int i = 0;
3842
3843 TypeExpr texpr = expr.ResolveAsTypeTerminal (ec, false);
3844 if (texpr == null)
3845 return false;
3846
3847 expr_type = texpr.Type;
3848
3849 //
3850 // The type must be an IDisposable or an implicit conversion
3851 // must exist.
3852 //
3853 converted_vars = new Expression [var_list.Count];
3854 resolved_vars = new Expression [var_list.Count];
3855 assign = new ExpressionStatement [var_list.Count];
3856
3857 bool need_conv = !TypeManager.ImplementsInterface (
3858 expr_type, TypeManager.idisposable_type);
3859
3860 foreach (DictionaryEntry e in var_list){
3861 Expression var = (Expression) e.Key;
3862
3863 var = var.ResolveLValue (ec, new EmptyExpression (), loc);
3864 if (var == null)
3865 return false;
3866
3867 resolved_vars [i] = var;
3868
3869 if (!need_conv) {
3870 i++;
3871 continue;
3872 }
3873
3874 converted_vars [i] = Convert.ImplicitConversion (
3875 ec, var, TypeManager.idisposable_type, loc);
3876
3877 if (converted_vars [i] == null) {
3878 Error_IsNotConvertibleToIDisposable ();
3879 return false;
3880 }
3881
3882 i++;
3883 }
3884
3885 i = 0;
3886 foreach (DictionaryEntry e in var_list){
3887 Expression var = resolved_vars [i];
3888 Expression new_expr = (Expression) e.Value;
3889 Expression a;
3890
3891 a = new Assign (var, new_expr, loc);
3892 a = a.Resolve (ec);
3893 if (a == null)
3894 return false;
3895
3896 if (!need_conv)
3897 converted_vars [i] = var;
3898 assign [i] = (ExpressionStatement) a;
3899 i++;
3900 }
3901
3902 return true;
3903 }
3904
3905 void Error_IsNotConvertibleToIDisposable ()
3906 {
3907 Report.Error (1674, loc, "`{0}': type used in a using statement must be implicitly convertible to `System.IDisposable'",
3908 TypeManager.CSharpName (expr_type));
3909 }
3910
3911 bool ResolveExpression (EmitContext ec)
3912 {
3913 if (!TypeManager.ImplementsInterface (expr_type, TypeManager.idisposable_type)){
3914 if (Convert.ImplicitConversion (ec, expr, TypeManager.idisposable_type, loc) == null) {
3915 Error_IsNotConvertibleToIDisposable ();
3916 return false;
3917 }
3918 }
3919
3920 return true;
3921 }
3922
3923 //
3924 // Emits the code for the case of using using a local variable declaration.
3925 //
3926 void EmitLocalVariableDecls (EmitContext ec)
3927 {
3928 ILGenerator ig = ec.ig;
3929 int i = 0;
3930
3931 for (i = 0; i < assign.Length; i++) {
3932 assign [i].EmitStatement (ec);
3933
3934 if (emit_finally)
3935 ig.BeginExceptionBlock ();
3936 }
3937 Statement.Emit (ec);
3938
3939 var_list.Reverse ();
3940
3941 DoEmitFinally (ec);
3942 }
3943
3944 void EmitLocalVariableDeclFinally (EmitContext ec)
3945 {
3946 ILGenerator ig = ec.ig;
3947
3948 int i = assign.Length;
3949 for (int ii = 0; ii < var_list.Count; ++ii){
3950 Expression var = resolved_vars [--i];
3951 Label skip = ig.DefineLabel ();
3952
3953 ig.BeginFinallyBlock ();
3954
3955 if (!var.Type.IsValueType) {
3956 var.Emit (ec);
3957 ig.Emit (OpCodes.Brfalse, skip);
3958 converted_vars [i].Emit (ec);
3959 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
3960 } else {
3961 Expression ml = Expression.MemberLookup(ec.ContainerType, TypeManager.idisposable_type, var.Type, "Dispose", Mono.CSharp.Location.Null);
3962
3963 if (!(ml is MethodGroupExpr)) {
3964 var.Emit (ec);
3965 ig.Emit (OpCodes.Box, var.Type);
3966 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
3967 } else {
3968 MethodInfo mi = null;
3969
3970 foreach (MethodInfo mk in ((MethodGroupExpr) ml).Methods) {
3971 if (TypeManager.GetParameterData (mk).Count == 0) {
3972 mi = mk;
3973 break;
3974 }
3975 }
3976
3977 if (mi == null) {
3978 Report.Error(-100, Mono.CSharp.Location.Null, "Internal error: No Dispose method which takes 0 parameters.");
3979 return;
3980 }
3981
3982 IMemoryLocation mloc = (IMemoryLocation) var;
3983
3984 mloc.AddressOf (ec, AddressOp.Load);
3985 ig.Emit (OpCodes.Call, mi);
3986 }
3987 }
3988
3989 ig.MarkLabel (skip);
3990
3991 if (emit_finally) {
3992 ig.EndExceptionBlock ();
3993 if (i > 0)
3994 ig.BeginFinallyBlock ();
3995 }
3996 }
3997 }
3998
3999 void EmitExpression (EmitContext ec)
4000 {
4001 //
4002 // Make a copy of the expression and operate on that.
4003 //
4004 ILGenerator ig = ec.ig;
4005 local_copy = ig.DeclareLocal (expr_type);
4006
4007 expr.Emit (ec);
4008 ig.Emit (OpCodes.Stloc, local_copy);
4009
4010 if (emit_finally)
4011 ig.BeginExceptionBlock ();
4012
4013 Statement.Emit (ec);
4014
4015 DoEmitFinally (ec);
4016 if (emit_finally)
4017 ig.EndExceptionBlock ();
4018 }
4019
4020 void EmitExpressionFinally (EmitContext ec)
4021 {
4022 ILGenerator ig = ec.ig;
4023 if (!local_copy.LocalType.IsValueType) {
4024 Label skip = ig.DefineLabel ();
4025 ig.Emit (OpCodes.Ldloc, local_copy);
4026 ig.Emit (OpCodes.Brfalse, skip);
4027 ig.Emit (OpCodes.Ldloc, local_copy);
4028 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4029 ig.MarkLabel (skip);
4030 } else {
4031 Expression ml = Expression.MemberLookup(ec.ContainerType, TypeManager.idisposable_type, local_copy.LocalType, "Dispose", Mono.CSharp.Location.Null);
4032
4033 if (!(ml is MethodGroupExpr)) {
4034 ig.Emit (OpCodes.Ldloc, local_copy);
4035 ig.Emit (OpCodes.Box, local_copy.LocalType);
4036 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4037 } else {
4038 MethodInfo mi = null;
4039
4040 foreach (MethodInfo mk in ((MethodGroupExpr) ml).Methods) {
4041 if (TypeManager.GetParameterData (mk).Count == 0) {
4042 mi = mk;
4043 break;
4044 }
4045 }
4046
4047 if (mi == null) {
4048 Report.Error(-100, Mono.CSharp.Location.Null, "Internal error: No Dispose method which takes 0 parameters.");
4049 return;
4050 }
4051
4052 ig.Emit (OpCodes.Ldloca, local_copy);
4053 ig.Emit (OpCodes.Call, mi);
4054 }
4055 }
4056 }
4057
4058 public override bool Resolve (EmitContext ec)
4059 {
4060 if (expression_or_block is DictionaryEntry){
4061 expr = (Expression) ((DictionaryEntry) expression_or_block).Key;
4062 var_list = (ArrayList)((DictionaryEntry)expression_or_block).Value;
4063
4064 if (!ResolveLocalVariableDecls (ec))
4065 return false;
4066
4067 } else if (expression_or_block is Expression){
4068 expr = (Expression) expression_or_block;
4069
4070 expr = expr.Resolve (ec);
4071 if (expr == null)
4072 return false;
4073
4074 expr_type = expr.Type;
4075
4076 if (!ResolveExpression (ec))
4077 return false;
4078 }
4079
4080 FlowBranchingException branching = ec.StartFlowBranching (this);
4081
4082 bool ok = Statement.Resolve (ec);
4083
4084 if (!ok) {
4085 ec.KillFlowBranching ();
4086 return false;
4087 }
4088
4089 ResolveFinally (branching);
4090 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
4091
4092 if (reachability.Returns != FlowBranching.FlowReturns.Always) {
4093 // Unfortunately, System.Reflection.Emit automatically emits a leave
4094 // to the end of the finally block. This is a problem if `returns'
4095 // is true since we may jump to a point after the end of the method.
4096 // As a workaround, emit an explicit ret here.
4097 ec.NeedReturnLabel ();
4098 }
4099
4100 return true;
4101 }
4102
4103 protected override void DoEmit (EmitContext ec)
4104 {
4105 if (expression_or_block is DictionaryEntry)
4106 EmitLocalVariableDecls (ec);
4107 else if (expression_or_block is Expression)
4108 EmitExpression (ec);
4109 }
4110
4111 public override void EmitFinally (EmitContext ec)
4112 {
4113 if (expression_or_block is DictionaryEntry)
4114 EmitLocalVariableDeclFinally (ec);
4115 else if (expression_or_block is Expression)
4116 EmitExpressionFinally (ec);
4117 }
4118 }
4119
4120 /// <summary>
4121 /// Implementation of the foreach C# statement
4122 /// </summary>
4123 public class Foreach : Statement {
4124 Expression type;
4125 Expression variable;
4126 Expression expr;
4127 Statement statement;
4128 ArrayForeach array;
4129 CollectionForeach collection;
4130
4131 public Foreach (Expression type, LocalVariableReference var, Expression expr,
4132 Statement stmt, Location l)
4133 {
4134 this.type = type;
4135 this.variable = var;
4136 this.expr = expr;
4137 statement = stmt;
4138 loc = l;
4139 }
4140
4141 public Statement Statement {
4142 get { return statement; }
4143 }
4144
4145 public override bool Resolve (EmitContext ec)
4146 {
4147 expr = expr.Resolve (ec);
4148 if (expr == null)
4149 return false;
4150
4151 Constant c = expr as Constant;
4152 if (c != null && c.GetValue () == null) {
4153 Report.Error (186, loc, "Use of null is not valid in this context");
4154 return false;
4155 }
4156
4157 TypeExpr texpr = type.ResolveAsTypeTerminal (ec, false);
4158 if (texpr == null)
4159 return false;
4160
4161 Type var_type = texpr.Type;
4162
4163 if (expr.eclass == ExprClass.MethodGroup || expr is AnonymousMethod) {
4164 Report.Error (446, expr.Location, "Foreach statement cannot operate on a `{0}'",
4165 expr.ExprClassName);
4166 return false;
4167 }
4168
4169 //
4170 // We need an instance variable. Not sure this is the best
4171 // way of doing this.
4172 //
4173 // FIXME: When we implement propertyaccess, will those turn
4174 // out to return values in ExprClass? I think they should.
4175 //
4176 if (!(expr.eclass == ExprClass.Variable || expr.eclass == ExprClass.Value ||
4177 expr.eclass == ExprClass.PropertyAccess || expr.eclass == ExprClass.IndexerAccess)){
4178 collection.Error_Enumerator ();
4179 return false;
4180 }
4181
4182 if (expr.Type.IsArray) {
4183 array = new ArrayForeach (var_type, variable, expr, statement, loc);
4184 return array.Resolve (ec);
4185 } else {
4186 collection = new CollectionForeach (
4187 var_type, variable, expr, statement, loc);
4188 return collection.Resolve (ec);
4189 }
4190 }
4191
4192 protected override void DoEmit (EmitContext ec)
4193 {
4194 ILGenerator ig = ec.ig;
4195
4196 Label old_begin = ec.LoopBegin, old_end = ec.LoopEnd;
4197 ec.LoopBegin = ig.DefineLabel ();
4198 ec.LoopEnd = ig.DefineLabel ();
4199
4200 if (collection != null)
4201 collection.Emit (ec);
4202 else
4203 array.Emit (ec);
4204
4205 ec.LoopBegin = old_begin;
4206 ec.LoopEnd = old_end;
4207 }
4208
4209 protected class ArrayCounter : TemporaryVariable
4210 {
4211 public ArrayCounter (Location loc)
4212 : base (TypeManager.int32_type, loc)
4213 { }
4214
4215 public void Initialize (EmitContext ec)
4216 {
4217 EmitThis (ec);
4218 ec.ig.Emit (OpCodes.Ldc_I4_0);
4219 EmitStore (ec.ig);
4220 }
4221
4222 public void Increment (EmitContext ec)
4223 {
4224 EmitThis (ec);
4225 Emit (ec);
4226 ec.ig.Emit (OpCodes.Ldc_I4_1);
4227 ec.ig.Emit (OpCodes.Add);
4228 EmitStore (ec.ig);
4229 }
4230 }
4231
4232 protected class ArrayForeach : Statement
4233 {
4234 Expression variable, expr, conv;
4235 Statement statement;
4236 Type array_type;
4237 Type var_type;
4238 TemporaryVariable[] lengths;
4239 ArrayCounter[] counter;
4240 int rank;
4241
4242 TemporaryVariable copy;
4243 Expression access;
4244
4245 public ArrayForeach (Type var_type, Expression var,
4246 Expression expr, Statement stmt, Location l)
4247 {
4248 this.var_type = var_type;
4249 this.variable = var;
4250 this.expr = expr;
4251 statement = stmt;
4252 loc = l;
4253 }
4254
4255 public override bool Resolve (EmitContext ec)
4256 {
4257 array_type = expr.Type;
4258 rank = array_type.GetArrayRank ();
4259
4260 copy = new TemporaryVariable (array_type, loc);
4261 copy.Resolve (ec);
4262
4263 counter = new ArrayCounter [rank];
4264 lengths = new TemporaryVariable [rank];
4265
4266 ArrayList list = new ArrayList ();
4267 for (int i = 0; i < rank; i++) {
4268 counter [i] = new ArrayCounter (loc);
4269 counter [i].Resolve (ec);
4270
4271 lengths [i] = new TemporaryVariable (TypeManager.int32_type, loc);
4272 lengths [i].Resolve (ec);
4273
4274 list.Add (counter [i]);
4275 }
4276
4277 access = new ElementAccess (copy, list).Resolve (ec);
4278 if (access == null)
4279 return false;
4280
4281 conv = Convert.ExplicitConversion (ec, access, var_type, loc);
4282 if (conv == null)
4283 return false;
4284
4285 bool ok = true;
4286
4287 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
4288 ec.CurrentBranching.CreateSibling ();
4289
4290 variable = variable.ResolveLValue (ec, conv, loc);
4291 if (variable == null)
4292 ok = false;
4293
4294 if (!statement.Resolve (ec))
4295 ok = false;
4296
4297 ec.EndFlowBranching ();
4298
4299 return ok;
4300 }
4301
4302 protected override void DoEmit (EmitContext ec)
4303 {
4304 ILGenerator ig = ec.ig;
4305
4306 copy.Store (ec, expr);
4307
4308 Label[] test = new Label [rank];
4309 Label[] loop = new Label [rank];
4310
4311 for (int i = 0; i < rank; i++) {
4312 test [i] = ig.DefineLabel ();
4313 loop [i] = ig.DefineLabel ();
4314
4315 lengths [i].EmitThis (ec);
4316 ((ArrayAccess) access).EmitGetLength (ec, i);
4317 lengths [i].EmitStore (ig);
4318 }
4319
4320 for (int i = 0; i < rank; i++) {
4321 counter [i].Initialize (ec);
4322
4323 ig.Emit (OpCodes.Br, test [i]);
4324 ig.MarkLabel (loop [i]);
4325 }
4326
4327 ((IAssignMethod) variable).EmitAssign (ec, conv, false, false);
4328
4329 statement.Emit (ec);
4330
4331 ig.MarkLabel (ec.LoopBegin);
4332
4333 for (int i = rank - 1; i >= 0; i--){
4334 counter [i].Increment (ec);
4335
4336 ig.MarkLabel (test [i]);
4337 counter [i].Emit (ec);
4338 lengths [i].Emit (ec);
4339 ig.Emit (OpCodes.Blt, loop [i]);
4340 }
4341
4342 ig.MarkLabel (ec.LoopEnd);
4343 }
4344 }
4345
4346 protected class CollectionForeach : ExceptionStatement
4347 {
4348 Expression variable, expr;
4349 Statement statement;
4350
4351 TemporaryVariable enumerator;
4352 Expression init;
4353 Statement loop;
4354
4355 MethodGroupExpr get_enumerator;
4356 PropertyExpr get_current;
4357 MethodInfo move_next;
4358 Type var_type, enumerator_type;
4359 bool is_disposable;
4360 bool enumerator_found;
4361
4362 public CollectionForeach (Type var_type, Expression var,
4363 Expression expr, Statement stmt, Location l)
4364 {
4365 this.var_type = var_type;
4366 this.variable = var;
4367 this.expr = expr;
4368 statement = stmt;
4369 loc = l;
4370 }
4371
4372 bool GetEnumeratorFilter (EmitContext ec, MethodInfo mi)
4373 {
4374 Type return_type = mi.ReturnType;
4375
4376 if ((return_type == TypeManager.ienumerator_type) && (mi.DeclaringType == TypeManager.string_type))
4377 //
4378 // Apply the same optimization as MS: skip the GetEnumerator
4379 // returning an IEnumerator, and use the one returning a
4380 // CharEnumerator instead. This allows us to avoid the
4381 // try-finally block and the boxing.
4382 //
4383 return false;
4384
4385 //
4386 // Ok, we can access it, now make sure that we can do something
4387 // with this `GetEnumerator'
4388 //
4389
4390 if (return_type == TypeManager.ienumerator_type ||
4391 TypeManager.ienumerator_type.IsAssignableFrom (return_type) ||
4392 (!RootContext.StdLib && TypeManager.ImplementsInterface (return_type, TypeManager.ienumerator_type))) {
4393 //
4394 // If it is not an interface, lets try to find the methods ourselves.
4395 // For example, if we have:
4396 // public class Foo : IEnumerator { public bool MoveNext () {} public int Current { get {}}}
4397 // We can avoid the iface call. This is a runtime perf boost.
4398 // even bigger if we have a ValueType, because we avoid the cost
4399 // of boxing.
4400 //
4401 // We have to make sure that both methods exist for us to take
4402 // this path. If one of the methods does not exist, we will just
4403 // use the interface. Sadly, this complex if statement is the only
4404 // way I could do this without a goto
4405 //
4406
4407 if (return_type.IsInterface && return_type.IsGenericType) {
4408 enumerator_type = return_type;
4409 if (!FetchGetCurrent (ec, return_type))
4410 get_current = new PropertyExpr (
4411 ec.ContainerType, TypeManager.ienumerator_getcurrent, loc);
4412 if (!FetchMoveNext (return_type))
4413 move_next = TypeManager.bool_movenext_void;
4414 return true;
4415 }
4416
4417 if (return_type.IsInterface ||
4418 !FetchMoveNext (return_type) ||
4419 !FetchGetCurrent (ec, return_type)) {
4420 enumerator_type = return_type;
4421 move_next = TypeManager.bool_movenext_void;
4422 get_current = new PropertyExpr (
4423 ec.ContainerType, TypeManager.ienumerator_getcurrent, loc);
4424 return true;
4425 }
4426 } else {
4427 //
4428 // Ok, so they dont return an IEnumerable, we will have to
4429 // find if they support the GetEnumerator pattern.
4430 //
4431
4432 if (TypeManager.HasElementType (return_type) || !FetchMoveNext (return_type) || !FetchGetCurrent (ec, return_type)) {
4433 Report.Error (202, loc, "foreach statement requires that the return type `{0}' of `{1}' must have a suitable public MoveNext method and public Current property",
4434 TypeManager.CSharpName (return_type), TypeManager.CSharpSignature (mi));
4435 return false;
4436 }
4437 }
4438
4439 enumerator_type = return_type;
4440 is_disposable = !enumerator_type.IsSealed ||
4441 TypeManager.ImplementsInterface (
4442 enumerator_type, TypeManager.idisposable_type);
4443
4444 return true;
4445 }
4446
4447 //
4448 // Retrieves a `public bool MoveNext ()' method from the Type `t'
4449 //
4450 bool FetchMoveNext (Type t)
4451 {
4452 MemberList move_next_list;
4453
4454 move_next_list = TypeContainer.FindMembers (
4455 t, MemberTypes.Method,
4456 Expression.AllBindingFlags,
4457 Type.FilterName, "MoveNext");
4458 if (move_next_list.Count == 0)
4459 return false;
4460
4461 bool found = false;
4462 foreach (MemberInfo m in move_next_list){
4463 MethodInfo mi = (MethodInfo) m;
4464
4465 if ((TypeManager.GetParameterData (mi).Count == 0) &&
4466 TypeManager.TypeToCoreType (mi.ReturnType) == TypeManager.bool_type) {
4467 move_next = mi;
4468 if (mi.IsPublic)
4469 return true;
4470 found = true;
4471 }
4472 }
4473
4474 return found;
4475 }
4476
4477 //
4478 // Retrieves a `public T get_Current ()' method from the Type `t'
4479 //
4480 bool FetchGetCurrent (EmitContext ec, Type t)
4481 {
4482 PropertyExpr pe = Expression.MemberLookup (
4483 ec.ContainerType, t, "Current", MemberTypes.Property,
4484 Expression.AllBindingFlags, loc) as PropertyExpr;
4485 if (pe == null)
4486 return false;
4487
4488 get_current = pe;
4489 return true;
4490 }
4491
4492 //
4493 // Retrieves a `public void Dispose ()' method from the Type `t'
4494 //
4495 static MethodInfo FetchMethodDispose (Type t)
4496 {
4497 MemberList dispose_list;
4498
4499 dispose_list = TypeContainer.FindMembers (
4500 t, MemberTypes.Method,
4501 BindingFlags.Public | BindingFlags.Instance,
4502 Type.FilterName, "Dispose");
4503 if (dispose_list.Count == 0)
4504 return null;
4505
4506 foreach (MemberInfo m in dispose_list){
4507 MethodInfo mi = (MethodInfo) m;
4508
4509 if (TypeManager.GetParameterData (mi).Count == 0){
4510 if (mi.ReturnType == TypeManager.void_type)
4511 return mi;
4512 }
4513 }
4514 return null;
4515 }
4516
4517 public void Error_Enumerator ()
4518 {
4519 if (enumerator_found) {
4520 return;
4521 }
4522
4523 Report.Error (1579, loc,
4524 "foreach statement cannot operate on variables of type `{0}' because it does not contain a definition for `GetEnumerator' or is not accessible",
4525 TypeManager.CSharpName (expr.Type));
4526 }
4527
4528 bool TryType (EmitContext ec, Type t)
4529 {
4530 MethodGroupExpr mg = Expression.MemberLookup (
4531 ec.ContainerType, t, "GetEnumerator", MemberTypes.Method,
4532 Expression.AllBindingFlags, loc) as MethodGroupExpr;
4533 if (mg == null)
4534 return false;
4535
4536 MethodBase result = null;
4537 MethodInfo tmp_move_next = null;
4538 PropertyExpr tmp_get_cur = null;
4539 Type tmp_enumerator_type = enumerator_type;
4540 foreach (MethodInfo mi in mg.Methods) {
4541 if (TypeManager.GetParameterData (mi).Count != 0)
4542 continue;
4543
4544 // Check whether GetEnumerator is public
4545 if ((mi.Attributes & MethodAttributes.Public) != MethodAttributes.Public)
4546 continue;
4547
4548 if (TypeManager.IsOverride (mi))
4549 continue;
4550
4551 enumerator_found = true;
4552
4553 if (!GetEnumeratorFilter (ec, mi)) {
4554 continue;
4555 }
4556
4557 result = mi;
4558 tmp_move_next = move_next;
4559 tmp_get_cur = get_current;
4560 tmp_enumerator_type = enumerator_type;
4561 if (mi.DeclaringType == t)
4562 break;
4563 }
4564
4565 if (result != null) {
4566 move_next = tmp_move_next;
4567 get_current = tmp_get_cur;
4568 enumerator_type = tmp_enumerator_type;
4569 MethodInfo[] mi = new MethodInfo[] { (MethodInfo) result };
4570 get_enumerator = new MethodGroupExpr (mi, loc);
4571
4572 if (t != expr.Type) {
4573 expr = Convert.ExplicitConversion (
4574 ec, expr, t, loc);
4575 if (expr == null)
4576 throw new InternalErrorException ();
4577 }
4578
4579 get_enumerator.InstanceExpression = expr;
4580 get_enumerator.IsBase = t != expr.Type;
4581
4582 return true;
4583 }
4584
4585 return false;
4586 }
4587
4588 bool ProbeCollectionType (EmitContext ec, Type t)
4589 {
4590 for (Type tt = t; tt != null && tt != TypeManager.object_type;){
4591 if (TryType (ec, tt))
4592 return true;
4593 tt = tt.BaseType;
4594 }
4595
4596 //
4597 // Now try to find the method in the interfaces
4598 //
4599 while (t != null){
4600 Type [] ifaces = t.GetInterfaces ();
4601
4602 foreach (Type i in ifaces){
4603 if (TryType (ec, i))
4604 return true;
4605 }
4606
4607 //
4608 // Since TypeBuilder.GetInterfaces only returns the interface
4609 // types for this type, we have to keep looping, but once
4610 // we hit a non-TypeBuilder (ie, a Type), then we know we are
4611 // done, because it returns all the types
4612 //
4613 if ((t is TypeBuilder))
4614 t = t.BaseType;
4615 else
4616 break;
4617 }
4618
4619 return false;
4620 }
4621
4622 public override bool Resolve (EmitContext ec)
4623 {
4624 enumerator_type = TypeManager.ienumerator_type;
4625 is_disposable = true;
4626
4627 if (!ProbeCollectionType (ec, expr.Type)) {
4628 Error_Enumerator ();
4629 return false;
4630 }
4631
4632 enumerator = new TemporaryVariable (enumerator_type, loc);
4633 enumerator.Resolve (ec);
4634
4635 init = new Invocation (get_enumerator, new ArrayList ());
4636 init = init.Resolve (ec);
4637 if (init == null)
4638 return false;
4639
4640 Expression move_next_expr;
4641 {
4642 MemberInfo[] mi = new MemberInfo[] { move_next };
4643 MethodGroupExpr mg = new MethodGroupExpr (mi, loc);
4644 mg.InstanceExpression = enumerator;
4645
4646 move_next_expr = new Invocation (mg, new ArrayList ());
4647 }
4648
4649 get_current.InstanceExpression = enumerator;
4650
4651 Statement block = new CollectionForeachStatement (
4652 var_type, variable, get_current, statement, loc);
4653
4654 loop = new While (move_next_expr, block, loc);
4655
4656 bool ok = true;
4657
4658 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
4659 ec.CurrentBranching.CreateSibling ();
4660
4661 FlowBranchingException branching = null;
4662 if (is_disposable)
4663 branching = ec.StartFlowBranching (this);
4664
4665 if (!loop.Resolve (ec))
4666 ok = false;
4667
4668 if (is_disposable) {
4669 ResolveFinally (branching);
4670 ec.EndFlowBranching ();
4671 } else
4672 emit_finally = true;
4673
4674 ec.EndFlowBranching ();
4675
4676 return ok;
4677 }
4678
4679 protected override void DoEmit (EmitContext ec)
4680 {
4681 ILGenerator ig = ec.ig;
4682
4683 enumerator.Store (ec, init);
4684
4685 //
4686 // Protect the code in a try/finalize block, so that
4687 // if the beast implement IDisposable, we get rid of it
4688 //
4689 if (is_disposable && emit_finally)
4690 ig.BeginExceptionBlock ();
4691
4692 loop.Emit (ec);
4693
4694 //
4695 // Now the finally block
4696 //
4697 if (is_disposable) {
4698 DoEmitFinally (ec);
4699 if (emit_finally)
4700 ig.EndExceptionBlock ();
4701 }
4702 }
4703
4704
4705 public override void EmitFinally (EmitContext ec)
4706 {
4707 ILGenerator ig = ec.ig;
4708
4709 if (enumerator_type.IsValueType) {
4710 MethodInfo mi = FetchMethodDispose (enumerator_type);
4711 if (mi != null) {
4712 enumerator.EmitLoadAddress (ec);
4713 ig.Emit (OpCodes.Call, mi);
4714 } else {
4715 enumerator.Emit (ec);
4716 ig.Emit (OpCodes.Box, enumerator_type);
4717 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4718 }
4719 } else {
4720 Label call_dispose = ig.DefineLabel ();
4721
4722 enumerator.Emit (ec);
4723 ig.Emit (OpCodes.Isinst, TypeManager.idisposable_type);
4724 ig.Emit (OpCodes.Dup);
4725 ig.Emit (OpCodes.Brtrue_S, call_dispose);
4726 ig.Emit (OpCodes.Pop);
4727
4728 Label end_finally = ig.DefineLabel ();
4729 ig.Emit (OpCodes.Br, end_finally);
4730
4731 ig.MarkLabel (call_dispose);
4732 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4733 ig.MarkLabel (end_finally);
4734 }
4735 }
4736 }
4737
4738 protected class CollectionForeachStatement : Statement
4739 {
4740 Type type;
4741 Expression variable, current, conv;
4742 Statement statement;
4743 Assign assign;
4744
4745 public CollectionForeachStatement (Type type, Expression variable,
4746 Expression current, Statement statement,
4747 Location loc)
4748 {
4749 this.type = type;
4750 this.variable = variable;
4751 this.current = current;
4752 this.statement = statement;
4753 this.loc = loc;
4754 }
4755
4756 public override bool Resolve (EmitContext ec)
4757 {
4758 current = current.Resolve (ec);
4759 if (current == null)
4760 return false;
4761
4762 conv = Convert.ExplicitConversion (ec, current, type, loc);
4763 if (conv == null)
4764 return false;
4765
4766 assign = new Assign (variable, conv, loc);
4767 if (assign.Resolve (ec) == null)
4768 return false;
4769
4770 if (!statement.Resolve (ec))
4771 return false;
4772
4773 return true;
4774 }
4775
4776 protected override void DoEmit (EmitContext ec)
4777 {
4778 assign.EmitStatement (ec);
4779 statement.Emit (ec);
4780 }
4781 }
4782 }
4783 }
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