2 // statement.cs: Statement representation for the IL tree.
5 // Miguel de Icaza (miguel@ximian.com)
6 // Martin Baulig (martin@ximian.com)
7 // Marek Safar (marek.safar@gmail.com)
9 // Copyright 2001, 2002, 2003 Ximian, Inc.
10 // Copyright 2003, 2004 Novell, Inc.
11 // Copyright 2011 Xamarin Inc.
15 using System.Collections.Generic;
18 using IKVM.Reflection.Emit;
20 using System.Reflection.Emit;
23 namespace Mono.CSharp {
25 public abstract class Statement {
27 protected bool reachable;
29 public bool IsUnreachable {
36 /// Resolves the statement, true means that all sub-statements
39 public virtual bool Resolve (BlockContext bc)
45 /// Return value indicates whether all code paths emitted return.
47 protected abstract void DoEmit (EmitContext ec);
49 public virtual void Emit (EmitContext ec)
54 if (ec.StatementEpilogue != null) {
60 // This routine must be overrided in derived classes and make copies
61 // of all the data that might be modified if resolved
63 protected abstract void CloneTo (CloneContext clonectx, Statement target);
65 public Statement Clone (CloneContext clonectx)
67 Statement s = (Statement) this.MemberwiseClone ();
68 CloneTo (clonectx, s);
72 public virtual Expression CreateExpressionTree (ResolveContext ec)
74 ec.Report.Error (834, loc, "A lambda expression with statement body cannot be converted to an expresion tree");
78 public virtual object Accept (StructuralVisitor visitor)
80 return visitor.Visit (this);
84 // Return value indicates whether statement has unreachable end
86 protected abstract bool DoFlowAnalysis (FlowAnalysisContext fc);
88 public bool FlowAnalysis (FlowAnalysisContext fc)
91 fc.UnreachableReported = false;
92 var res = DoFlowAnalysis (fc);
97 // Special handling cases
100 return DoFlowAnalysis (fc);
103 if (this is EmptyStatement || loc.IsNull)
106 if (fc.UnreachableReported)
109 fc.Report.Warning (162, 2, loc, "Unreachable code detected");
110 fc.UnreachableReported = true;
114 public virtual Reachability MarkReachable (Reachability rc)
116 if (!rc.IsUnreachable)
122 protected void CheckExitBoundaries (BlockContext bc, Block scope)
124 if (bc.CurrentBlock.ParametersBlock.Original != scope.ParametersBlock.Original) {
125 bc.Report.Error (1632, loc, "Control cannot leave the body of an anonymous method");
129 for (var b = bc.CurrentBlock; b != null && b != scope; b = b.Parent) {
130 if (b.IsFinallyBlock) {
131 Error_FinallyClauseExit (bc);
137 protected void Error_FinallyClauseExit (BlockContext bc)
139 bc.Report.Error (157, loc, "Control cannot leave the body of a finally clause");
143 public sealed class EmptyStatement : Statement
145 public EmptyStatement (Location loc)
150 public override bool Resolve (BlockContext ec)
155 public override void Emit (EmitContext ec)
159 protected override void DoEmit (EmitContext ec)
161 throw new NotSupportedException ();
164 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
169 protected override void CloneTo (CloneContext clonectx, Statement target)
174 public override object Accept (StructuralVisitor visitor)
176 return visitor.Visit (this);
180 public class If : Statement {
182 public Statement TrueStatement;
183 public Statement FalseStatement;
185 bool true_returns, false_returns;
187 public If (Expression bool_expr, Statement true_statement, Location l)
188 : this (bool_expr, true_statement, null, l)
192 public If (Expression bool_expr,
193 Statement true_statement,
194 Statement false_statement,
197 this.expr = bool_expr;
198 TrueStatement = true_statement;
199 FalseStatement = false_statement;
203 public Expression Expr {
209 public override bool Resolve (BlockContext ec)
211 expr = expr.Resolve (ec);
213 var ok = TrueStatement.Resolve (ec);
215 if (FalseStatement != null) {
216 ok &= FalseStatement.Resolve (ec);
222 protected override void DoEmit (EmitContext ec)
224 Label false_target = ec.DefineLabel ();
228 // If we're a boolean constant, Resolve() already
229 // eliminated dead code for us.
231 Constant c = expr as Constant;
233 c.EmitSideEffect (ec);
235 if (!c.IsDefaultValue)
236 TrueStatement.Emit (ec);
237 else if (FalseStatement != null)
238 FalseStatement.Emit (ec);
243 expr.EmitBranchable (ec, false_target, false);
245 TrueStatement.Emit (ec);
247 if (FalseStatement != null){
248 bool branch_emitted = false;
250 end = ec.DefineLabel ();
252 ec.Emit (OpCodes.Br, end);
253 branch_emitted = true;
256 ec.MarkLabel (false_target);
257 FalseStatement.Emit (ec);
262 ec.MarkLabel (false_target);
266 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
268 expr.FlowAnalysisConditional (fc);
270 var da_false = new DefiniteAssignmentBitSet (fc.DefiniteAssignmentOnFalse);
272 fc.DefiniteAssignment = fc.DefiniteAssignmentOnTrue;
274 var res = TrueStatement.FlowAnalysis (fc);
276 if (FalseStatement == null) {
277 var c = expr as Constant;
278 if (c != null && !c.IsDefaultValue)
282 fc.DefiniteAssignment = da_false;
284 fc.DefiniteAssignment &= da_false;
290 fc.DefiniteAssignment = da_false;
291 return FalseStatement.FlowAnalysis (fc);
294 var da_true = fc.DefiniteAssignment;
296 fc.DefiniteAssignment = da_false;
297 res &= FalseStatement.FlowAnalysis (fc);
299 if (!TrueStatement.IsUnreachable) {
300 if (false_returns || FalseStatement.IsUnreachable)
301 fc.DefiniteAssignment = da_true;
303 fc.DefiniteAssignment &= da_true;
309 public override Reachability MarkReachable (Reachability rc)
311 if (rc.IsUnreachable)
314 base.MarkReachable (rc);
316 var c = expr as Constant;
318 bool take = !c.IsDefaultValue;
320 rc = TrueStatement.MarkReachable (rc);
322 if (FalseStatement != null)
323 rc = FalseStatement.MarkReachable (rc);
329 var true_rc = TrueStatement.MarkReachable (rc);
330 true_returns = true_rc.IsUnreachable;
332 if (FalseStatement == null)
335 var false_rc = FalseStatement.MarkReachable (rc);
336 false_returns = false_rc.IsUnreachable;
338 return true_rc & false_rc;
341 protected override void CloneTo (CloneContext clonectx, Statement t)
345 target.expr = expr.Clone (clonectx);
346 target.TrueStatement = TrueStatement.Clone (clonectx);
347 if (FalseStatement != null)
348 target.FalseStatement = FalseStatement.Clone (clonectx);
351 public override object Accept (StructuralVisitor visitor)
353 return visitor.Visit (this);
357 public class Do : LoopStatement
359 public Expression expr;
360 bool iterator_reachable, end_reachable;
362 public Do (Statement statement, BooleanExpression bool_expr, Location doLocation, Location whileLocation)
367 WhileLocation = whileLocation;
370 public Location WhileLocation {
374 public override bool Resolve (BlockContext bc)
376 var ok = base.Resolve (bc);
378 expr = expr.Resolve (bc);
383 protected override void DoEmit (EmitContext ec)
385 Label loop = ec.DefineLabel ();
386 Label old_begin = ec.LoopBegin;
387 Label old_end = ec.LoopEnd;
389 ec.LoopBegin = ec.DefineLabel ();
390 ec.LoopEnd = ec.DefineLabel ();
394 ec.MarkLabel (ec.LoopBegin);
396 // Mark start of while condition
397 ec.Mark (WhileLocation);
400 // Dead code elimination
402 if (expr is Constant) {
403 bool res = !((Constant) expr).IsDefaultValue;
405 expr.EmitSideEffect (ec);
407 ec.Emit (OpCodes.Br, loop);
409 expr.EmitBranchable (ec, loop, true);
412 ec.MarkLabel (ec.LoopEnd);
414 ec.LoopBegin = old_begin;
415 ec.LoopEnd = old_end;
418 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
420 var res = Statement.FlowAnalysis (fc);
422 expr.FlowAnalysisConditional (fc);
424 fc.DefiniteAssignment = fc.DefiniteAssignmentOnFalse;
426 if (res && !iterator_reachable)
427 return !end_reachable;
429 if (!end_reachable) {
430 var c = expr as Constant;
431 if (c != null && !c.IsDefaultValue)
438 public override Reachability MarkReachable (Reachability rc)
440 base.MarkReachable (rc);
442 var body_rc = Statement.MarkReachable (rc);
444 if (body_rc.IsUnreachable && !iterator_reachable) {
445 expr = new UnreachableExpression (expr);
446 return end_reachable ? rc : Reachability.CreateUnreachable ();
449 if (!end_reachable) {
450 var c = expr as Constant;
451 if (c != null && !c.IsDefaultValue)
452 return Reachability.CreateUnreachable ();
458 protected override void CloneTo (CloneContext clonectx, Statement t)
462 target.Statement = Statement.Clone (clonectx);
463 target.expr = expr.Clone (clonectx);
466 public override object Accept (StructuralVisitor visitor)
468 return visitor.Visit (this);
471 public override void SetEndReachable ()
473 end_reachable = true;
476 public override void SetIteratorReachable ()
478 iterator_reachable = true;
482 public class While : LoopStatement
484 public Expression expr;
485 bool empty, infinite, end_reachable;
486 List<DefiniteAssignmentBitSet> end_reachable_das;
488 public While (BooleanExpression bool_expr, Statement statement, Location l)
491 this.expr = bool_expr;
495 public override bool Resolve (BlockContext bc)
499 expr = expr.Resolve (bc);
503 var c = expr as Constant;
505 empty = c.IsDefaultValue;
509 ok &= base.Resolve (bc);
513 protected override void DoEmit (EmitContext ec)
516 expr.EmitSideEffect (ec);
520 Label old_begin = ec.LoopBegin;
521 Label old_end = ec.LoopEnd;
523 ec.LoopBegin = ec.DefineLabel ();
524 ec.LoopEnd = ec.DefineLabel ();
527 // Inform whether we are infinite or not
529 if (expr is Constant) {
530 // expr is 'true', since the 'empty' case above handles the 'false' case
531 ec.MarkLabel (ec.LoopBegin);
533 if (ec.EmitAccurateDebugInfo)
534 ec.Emit (OpCodes.Nop);
536 expr.EmitSideEffect (ec);
538 ec.Emit (OpCodes.Br, ec.LoopBegin);
541 // Inform that we are infinite (ie, `we return'), only
542 // if we do not `break' inside the code.
544 ec.MarkLabel (ec.LoopEnd);
546 Label while_loop = ec.DefineLabel ();
548 ec.Emit (OpCodes.Br, ec.LoopBegin);
549 ec.MarkLabel (while_loop);
553 ec.MarkLabel (ec.LoopBegin);
556 expr.EmitBranchable (ec, while_loop, true);
558 ec.MarkLabel (ec.LoopEnd);
561 ec.LoopBegin = old_begin;
562 ec.LoopEnd = old_end;
565 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
567 expr.FlowAnalysisConditional (fc);
569 fc.DefiniteAssignment = fc.DefiniteAssignmentOnTrue;
570 var da_false = new DefiniteAssignmentBitSet (fc.DefiniteAssignmentOnFalse);
572 Statement.FlowAnalysis (fc);
575 // Special case infinite while with breaks
577 if (end_reachable_das != null) {
578 da_false = DefiniteAssignmentBitSet.And (end_reachable_das);
579 end_reachable_das = null;
582 fc.DefiniteAssignment = da_false;
584 if (infinite && !end_reachable)
590 public override Reachability MarkReachable (Reachability rc)
592 if (rc.IsUnreachable)
595 base.MarkReachable (rc);
598 // Special case unreachable while body
601 Statement.MarkReachable (Reachability.CreateUnreachable ());
605 Statement.MarkReachable (rc);
608 // When infinite while end is unreachable via break anything what follows is unreachable too
610 if (infinite && !end_reachable)
611 return Reachability.CreateUnreachable ();
616 protected override void CloneTo (CloneContext clonectx, Statement t)
618 While target = (While) t;
620 target.expr = expr.Clone (clonectx);
621 target.Statement = Statement.Clone (clonectx);
624 public override object Accept (StructuralVisitor visitor)
626 return visitor.Visit (this);
629 public override void AddEndDefiniteAssignment (FlowAnalysisContext fc)
634 if (end_reachable_das == null)
635 end_reachable_das = new List<DefiniteAssignmentBitSet> ();
637 end_reachable_das.Add (fc.DefiniteAssignment);
640 public override void SetEndReachable ()
642 end_reachable = true;
646 public class For : LoopStatement
648 bool infinite, empty, iterator_reachable, end_reachable;
649 List<DefiniteAssignmentBitSet> end_reachable_das;
651 public For (Location l)
657 public Statement Initializer {
661 public Expression Condition {
665 public Statement Iterator {
669 public override bool Resolve (BlockContext bc)
671 Initializer.Resolve (bc);
673 if (Condition != null) {
674 Condition = Condition.Resolve (bc);
675 var condition_constant = Condition as Constant;
676 if (condition_constant != null) {
677 if (condition_constant.IsDefaultValue) {
687 return base.Resolve (bc) && Iterator.Resolve (bc);
690 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
692 Initializer.FlowAnalysis (fc);
694 DefiniteAssignmentBitSet da_false;
695 if (Condition != null) {
696 Condition.FlowAnalysisConditional (fc);
697 fc.DefiniteAssignment = fc.DefiniteAssignmentOnTrue;
698 da_false = new DefiniteAssignmentBitSet (fc.DefiniteAssignmentOnFalse);
700 da_false = fc.BranchDefiniteAssignment ();
703 Statement.FlowAnalysis (fc);
705 Iterator.FlowAnalysis (fc);
708 // Special case infinite for with breaks
710 if (end_reachable_das != null) {
711 da_false = DefiniteAssignmentBitSet.And (end_reachable_das);
712 end_reachable_das = null;
715 fc.DefiniteAssignment = da_false;
717 if (infinite && !end_reachable)
723 public override Reachability MarkReachable (Reachability rc)
725 base.MarkReachable (rc);
727 Initializer.MarkReachable (rc);
729 var body_rc = Statement.MarkReachable (rc);
730 if (!body_rc.IsUnreachable || iterator_reachable) {
731 Iterator.MarkReachable (rc);
735 // When infinite for end is unreachable via break anything what follows is unreachable too
737 if (infinite && !end_reachable) {
738 return Reachability.CreateUnreachable ();
744 protected override void DoEmit (EmitContext ec)
746 if (Initializer != null)
747 Initializer.Emit (ec);
750 Condition.EmitSideEffect (ec);
754 Label old_begin = ec.LoopBegin;
755 Label old_end = ec.LoopEnd;
756 Label loop = ec.DefineLabel ();
757 Label test = ec.DefineLabel ();
759 ec.LoopBegin = ec.DefineLabel ();
760 ec.LoopEnd = ec.DefineLabel ();
762 ec.Emit (OpCodes.Br, test);
766 ec.MarkLabel (ec.LoopBegin);
771 // If test is null, there is no test, and we are just
774 if (Condition != null) {
775 ec.Mark (Condition.Location);
778 // The Resolve code already catches the case for
779 // Test == Constant (false) so we know that
782 if (Condition is Constant) {
783 Condition.EmitSideEffect (ec);
784 ec.Emit (OpCodes.Br, loop);
786 Condition.EmitBranchable (ec, loop, true);
790 ec.Emit (OpCodes.Br, loop);
791 ec.MarkLabel (ec.LoopEnd);
793 ec.LoopBegin = old_begin;
794 ec.LoopEnd = old_end;
797 protected override void CloneTo (CloneContext clonectx, Statement t)
799 For target = (For) t;
801 if (Initializer != null)
802 target.Initializer = Initializer.Clone (clonectx);
803 if (Condition != null)
804 target.Condition = Condition.Clone (clonectx);
805 if (Iterator != null)
806 target.Iterator = Iterator.Clone (clonectx);
807 target.Statement = Statement.Clone (clonectx);
810 public override object Accept (StructuralVisitor visitor)
812 return visitor.Visit (this);
815 public override void AddEndDefiniteAssignment (FlowAnalysisContext fc)
820 if (end_reachable_das == null)
821 end_reachable_das = new List<DefiniteAssignmentBitSet> ();
823 end_reachable_das.Add (fc.DefiniteAssignment);
826 public override void SetEndReachable ()
828 end_reachable = true;
831 public override void SetIteratorReachable ()
833 iterator_reachable = true;
837 public abstract class LoopStatement : Statement
839 protected LoopStatement (Statement statement)
841 Statement = statement;
844 public Statement Statement { get; set; }
846 public override bool Resolve (BlockContext bc)
848 var prev_loop = bc.EnclosingLoop;
849 var prev_los = bc.EnclosingLoopOrSwitch;
850 bc.EnclosingLoopOrSwitch = bc.EnclosingLoop = this;
851 var ok = Statement.Resolve (bc);
852 bc.EnclosingLoopOrSwitch = prev_los;
853 bc.EnclosingLoop = prev_loop;
859 // Needed by possibly infinite loops statements (for, while) and switch statment
861 public virtual void AddEndDefiniteAssignment (FlowAnalysisContext fc)
865 public virtual void SetEndReachable ()
869 public virtual void SetIteratorReachable ()
874 public class StatementExpression : Statement
876 ExpressionStatement expr;
878 public StatementExpression (ExpressionStatement expr)
881 loc = expr.StartLocation;
884 public StatementExpression (ExpressionStatement expr, Location loc)
890 public ExpressionStatement Expr {
896 protected override void CloneTo (CloneContext clonectx, Statement t)
898 StatementExpression target = (StatementExpression) t;
899 target.expr = (ExpressionStatement) expr.Clone (clonectx);
902 protected override void DoEmit (EmitContext ec)
904 expr.EmitStatement (ec);
907 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
909 expr.FlowAnalysis (fc);
913 public override Reachability MarkReachable (Reachability rc)
915 base.MarkReachable (rc);
916 expr.MarkReachable (rc);
920 public override bool Resolve (BlockContext ec)
922 expr = expr.ResolveStatement (ec);
926 public override object Accept (StructuralVisitor visitor)
928 return visitor.Visit (this);
932 public class StatementErrorExpression : Statement
936 public StatementErrorExpression (Expression expr)
939 this.loc = expr.StartLocation;
942 public Expression Expr {
948 public override bool Resolve (BlockContext bc)
950 expr.Error_InvalidExpressionStatement (bc);
954 protected override void DoEmit (EmitContext ec)
956 throw new NotSupportedException ();
959 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
964 protected override void CloneTo (CloneContext clonectx, Statement target)
966 var t = (StatementErrorExpression) target;
968 t.expr = expr.Clone (clonectx);
971 public override object Accept (StructuralVisitor visitor)
973 return visitor.Visit (this);
978 // Simple version of statement list not requiring a block
980 public class StatementList : Statement
982 List<Statement> statements;
984 public StatementList (Statement first, Statement second)
986 statements = new List<Statement> { first, second };
990 public IList<Statement> Statements {
997 public void Add (Statement statement)
999 statements.Add (statement);
1002 public override bool Resolve (BlockContext ec)
1004 foreach (var s in statements)
1010 protected override void DoEmit (EmitContext ec)
1012 foreach (var s in statements)
1016 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1018 foreach (var s in statements)
1019 s.FlowAnalysis (fc);
1024 public override Reachability MarkReachable (Reachability rc)
1026 base.MarkReachable (rc);
1028 Reachability res = rc;
1029 foreach (var s in statements)
1030 res = s.MarkReachable (rc);
1035 protected override void CloneTo (CloneContext clonectx, Statement target)
1037 StatementList t = (StatementList) target;
1039 t.statements = new List<Statement> (statements.Count);
1040 foreach (Statement s in statements)
1041 t.statements.Add (s.Clone (clonectx));
1044 public override object Accept (StructuralVisitor visitor)
1046 return visitor.Visit (this);
1051 // For statements which require special handling when inside try or catch block
1053 public abstract class ExitStatement : Statement
1055 protected bool unwind_protect;
1057 protected abstract bool DoResolve (BlockContext bc);
1058 protected abstract bool IsLocalExit { get; }
1060 public override bool Resolve (BlockContext bc)
1062 var res = DoResolve (bc);
1066 // We are inside finally scope but is it the scope we are exiting
1068 if (bc.HasSet (ResolveContext.Options.FinallyScope)) {
1070 for (var b = bc.CurrentBlock; b != null; b = b.Parent) {
1071 if (b.IsFinallyBlock) {
1072 Error_FinallyClauseExit (bc);
1076 if (b is ParametersBlock)
1082 unwind_protect = bc.HasAny (ResolveContext.Options.TryScope | ResolveContext.Options.CatchScope);
1086 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1091 if (fc.TryFinally != null) {
1092 fc.TryFinally.RegisterForControlExitCheck (new DefiniteAssignmentBitSet (fc.DefiniteAssignment));
1094 fc.ParametersBlock.CheckControlExit (fc);
1102 /// Implements the return statement
1104 public class Return : ExitStatement
1108 public Return (Expression expr, Location l)
1116 public Expression Expr {
1125 protected override bool IsLocalExit {
1133 protected override bool DoResolve (BlockContext ec)
1135 var block_return_type = ec.ReturnType;
1138 if (block_return_type.Kind == MemberKind.Void)
1142 // Return must not be followed by an expression when
1143 // the method return type is Task
1145 if (ec.CurrentAnonymousMethod is AsyncInitializer) {
1146 var storey = (AsyncTaskStorey) ec.CurrentAnonymousMethod.Storey;
1147 if (storey.ReturnType == ec.Module.PredefinedTypes.Task.TypeSpec) {
1149 // Extra trick not to emit ret/leave inside awaiter body
1151 expr = EmptyExpression.Null;
1155 if (storey.ReturnType.IsGenericTask)
1156 block_return_type = storey.ReturnType.TypeArguments[0];
1159 if (ec.CurrentIterator != null) {
1160 Error_ReturnFromIterator (ec);
1161 } else if (block_return_type != InternalType.ErrorType) {
1162 ec.Report.Error (126, loc,
1163 "An object of a type convertible to `{0}' is required for the return statement",
1164 block_return_type.GetSignatureForError ());
1170 expr = expr.Resolve (ec);
1172 AnonymousExpression am = ec.CurrentAnonymousMethod;
1174 if (block_return_type.Kind == MemberKind.Void) {
1175 ec.Report.Error (127, loc,
1176 "`{0}': A return keyword must not be followed by any expression when method returns void",
1177 ec.GetSignatureForError ());
1182 if (am.IsIterator) {
1183 Error_ReturnFromIterator (ec);
1187 var async_block = am as AsyncInitializer;
1188 if (async_block != null) {
1190 var storey = (AsyncTaskStorey) am.Storey;
1191 var async_type = storey.ReturnType;
1193 if (async_type == null && async_block.ReturnTypeInference != null) {
1194 if (expr.Type.Kind == MemberKind.Void && !(this is ContextualReturn))
1195 ec.Report.Error (4029, loc, "Cannot return an expression of type `void'");
1197 async_block.ReturnTypeInference.AddCommonTypeBoundAsync (expr.Type);
1201 if (async_type.Kind == MemberKind.Void) {
1202 ec.Report.Error (8030, loc,
1203 "Anonymous function or lambda expression converted to a void returning delegate cannot return a value");
1207 if (!async_type.IsGenericTask) {
1208 if (this is ContextualReturn)
1211 if (async_block.DelegateType != null) {
1212 ec.Report.Error (8031, loc,
1213 "Async lambda expression or anonymous method converted to a `Task' cannot return a value. Consider returning `Task<T>'");
1215 ec.Report.Error (1997, loc,
1216 "`{0}': A return keyword must not be followed by an expression when async method returns `Task'. Consider using `Task<T>' return type",
1217 ec.GetSignatureForError ());
1223 // The return type is actually Task<T> type argument
1225 if (expr.Type == async_type) {
1226 ec.Report.Error (4016, loc,
1227 "`{0}': The return expression type of async method must be `{1}' rather than `Task<{1}>'",
1228 ec.GetSignatureForError (), async_type.TypeArguments[0].GetSignatureForError ());
1230 block_return_type = async_type.TypeArguments[0];
1234 if (block_return_type.Kind == MemberKind.Void) {
1235 ec.Report.Error (8030, loc,
1236 "Anonymous function or lambda expression converted to a void returning delegate cannot return a value");
1240 var l = am as AnonymousMethodBody;
1241 if (l != null && expr != null) {
1242 if (l.ReturnTypeInference != null) {
1243 l.ReturnTypeInference.AddCommonTypeBound (expr.Type);
1248 // Try to optimize simple lambda. Only when optimizations are enabled not to cause
1249 // unexpected debugging experience
1251 if (this is ContextualReturn && !ec.IsInProbingMode && ec.Module.Compiler.Settings.Optimize) {
1252 l.DirectMethodGroupConversion = expr.CanReduceLambda (l);
1261 if (expr.Type != block_return_type && expr.Type != InternalType.ErrorType) {
1262 expr = Convert.ImplicitConversionRequired (ec, expr, block_return_type, loc);
1265 if (am != null && block_return_type == ec.ReturnType) {
1266 ec.Report.Error (1662, loc,
1267 "Cannot convert `{0}' to delegate type `{1}' because some of the return types in the block are not implicitly convertible to the delegate return type",
1268 am.ContainerType, am.GetSignatureForError ());
1277 protected override void DoEmit (EmitContext ec)
1281 var async_body = ec.CurrentAnonymousMethod as AsyncInitializer;
1282 if (async_body != null) {
1283 var storey = (AsyncTaskStorey)async_body.Storey;
1284 Label exit_label = async_body.BodyEnd;
1287 // It's null for await without async
1289 if (storey.HoistedReturnValue != null) {
1291 // Special case hoisted return value (happens in try/finally scenario)
1293 if (ec.TryFinallyUnwind != null) {
1294 if (storey.HoistedReturnValue is VariableReference) {
1295 storey.HoistedReturnValue = ec.GetTemporaryField (storey.HoistedReturnValue.Type);
1298 exit_label = TryFinally.EmitRedirectedReturn (ec, async_body);
1301 var async_return = (IAssignMethod)storey.HoistedReturnValue;
1302 async_return.EmitAssign (ec, expr, false, false);
1307 if (ec.TryFinallyUnwind != null)
1308 exit_label = TryFinally.EmitRedirectedReturn (ec, async_body);
1311 ec.Emit (OpCodes.Leave, exit_label);
1318 if (unwind_protect || ec.EmitAccurateDebugInfo)
1319 ec.Emit (OpCodes.Stloc, ec.TemporaryReturn ());
1322 if (unwind_protect) {
1323 ec.Emit (OpCodes.Leave, ec.CreateReturnLabel ());
1324 } else if (ec.EmitAccurateDebugInfo) {
1325 ec.Emit (OpCodes.Br, ec.CreateReturnLabel ());
1327 ec.Emit (OpCodes.Ret);
1331 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1334 expr.FlowAnalysis (fc);
1336 base.DoFlowAnalysis (fc);
1340 void Error_ReturnFromIterator (ResolveContext rc)
1342 rc.Report.Error (1622, loc,
1343 "Cannot return a value from iterators. Use the yield return statement to return a value, or yield break to end the iteration");
1346 public override Reachability MarkReachable (Reachability rc)
1348 base.MarkReachable (rc);
1349 return Reachability.CreateUnreachable ();
1352 protected override void CloneTo (CloneContext clonectx, Statement t)
1354 Return target = (Return) t;
1355 // It's null for simple return;
1357 target.expr = expr.Clone (clonectx);
1360 public override object Accept (StructuralVisitor visitor)
1362 return visitor.Visit (this);
1366 public class Goto : ExitStatement
1369 LabeledStatement label;
1370 TryFinally try_finally;
1372 public Goto (string label, Location l)
1378 public string Target {
1379 get { return target; }
1382 protected override bool IsLocalExit {
1388 protected override bool DoResolve (BlockContext bc)
1390 label = bc.CurrentBlock.LookupLabel (target);
1391 if (label == null) {
1392 Error_UnknownLabel (bc, target, loc);
1396 try_finally = bc.CurrentTryBlock as TryFinally;
1398 CheckExitBoundaries (bc, label.Block);
1403 public static void Error_UnknownLabel (BlockContext bc, string label, Location loc)
1405 bc.Report.Error (159, loc, "The label `{0}:' could not be found within the scope of the goto statement",
1409 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1411 if (fc.LabelStack == null) {
1412 fc.LabelStack = new List<LabeledStatement> ();
1413 } else if (fc.LabelStack.Contains (label)) {
1417 fc.LabelStack.Add (label);
1418 label.Block.ScanGotoJump (label, fc);
1419 fc.LabelStack.Remove (label);
1423 public override Reachability MarkReachable (Reachability rc)
1425 if (rc.IsUnreachable)
1428 base.MarkReachable (rc);
1430 if (try_finally != null) {
1431 if (try_finally.FinallyBlock.HasReachableClosingBrace) {
1432 label.AddGotoReference (rc, false);
1434 label.AddGotoReference (rc, true);
1437 label.AddGotoReference (rc, false);
1440 return Reachability.CreateUnreachable ();
1443 protected override void CloneTo (CloneContext clonectx, Statement target)
1448 protected override void DoEmit (EmitContext ec)
1451 throw new InternalErrorException ("goto emitted before target resolved");
1453 Label l = label.LabelTarget (ec);
1455 if (ec.TryFinallyUnwind != null && IsLeavingFinally (label.Block)) {
1456 var async_body = (AsyncInitializer) ec.CurrentAnonymousMethod;
1457 l = TryFinally.EmitRedirectedJump (ec, async_body, l, label.Block);
1460 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, l);
1463 bool IsLeavingFinally (Block labelBlock)
1465 var b = try_finally.Statement as Block;
1467 if (b == labelBlock)
1476 public override object Accept (StructuralVisitor visitor)
1478 return visitor.Visit (this);
1482 public class LabeledStatement : Statement {
1490 public LabeledStatement (string name, Block block, Location l)
1497 public Label LabelTarget (EmitContext ec)
1502 label = ec.DefineLabel ();
1507 public Block Block {
1513 public string Name {
1514 get { return name; }
1517 protected override void CloneTo (CloneContext clonectx, Statement target)
1519 var t = (LabeledStatement) target;
1521 t.block = clonectx.RemapBlockCopy (block);
1524 public override bool Resolve (BlockContext bc)
1529 protected override void DoEmit (EmitContext ec)
1532 ec.MarkLabel (label);
1535 ec.Emit (OpCodes.Br_S, label);
1538 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1541 fc.Report.Warning (164, 2, loc, "This label has not been referenced");
1547 public override Reachability MarkReachable (Reachability rc)
1549 base.MarkReachable (rc);
1552 rc = new Reachability ();
1557 public void AddGotoReference (Reachability rc, bool finalTarget)
1566 // Label is final target when goto jumps out of try block with
1567 // finally clause. In that case we need leave with target but in C#
1568 // terms the label is unreachable. Using finalTarget we emit
1569 // explicit label not just marker
1572 this.finalTarget = true;
1576 block.ScanGotoJump (this);
1579 public override object Accept (StructuralVisitor visitor)
1581 return visitor.Visit (this);
1587 /// `goto default' statement
1589 public class GotoDefault : SwitchGoto
1591 public GotoDefault (Location l)
1596 public override bool Resolve (BlockContext bc)
1598 if (bc.Switch == null) {
1599 Error_GotoCaseRequiresSwitchBlock (bc);
1603 bc.Switch.RegisterGotoCase (null, null);
1609 protected override void DoEmit (EmitContext ec)
1611 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, ec.Switch.DefaultLabel.GetILLabel (ec));
1614 public override Reachability MarkReachable (Reachability rc)
1616 if (!rc.IsUnreachable) {
1617 var label = switch_statement.DefaultLabel;
1618 if (label.IsUnreachable) {
1619 label.MarkReachable (rc);
1620 switch_statement.Block.ScanGotoJump (label);
1624 return base.MarkReachable (rc);
1627 public override object Accept (StructuralVisitor visitor)
1629 return visitor.Visit (this);
1634 /// `goto case' statement
1636 public class GotoCase : SwitchGoto
1640 public GotoCase (Expression e, Location l)
1646 public Expression Expr {
1652 public SwitchLabel Label { get; set; }
1654 public override bool Resolve (BlockContext ec)
1656 if (ec.Switch == null) {
1657 Error_GotoCaseRequiresSwitchBlock (ec);
1661 Constant c = expr.ResolveLabelConstant (ec);
1667 if (ec.Switch.IsNullable && c is NullLiteral) {
1670 TypeSpec type = ec.Switch.SwitchType;
1671 res = c.Reduce (ec, type);
1673 c.Error_ValueCannotBeConverted (ec, type, true);
1677 if (!Convert.ImplicitStandardConversionExists (c, type))
1678 ec.Report.Warning (469, 2, loc,
1679 "The `goto case' value is not implicitly convertible to type `{0}'",
1680 type.GetSignatureForError ());
1684 ec.Switch.RegisterGotoCase (this, res);
1691 protected override void DoEmit (EmitContext ec)
1693 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, Label.GetILLabel (ec));
1696 protected override void CloneTo (CloneContext clonectx, Statement t)
1698 GotoCase target = (GotoCase) t;
1700 target.expr = expr.Clone (clonectx);
1703 public override Reachability MarkReachable (Reachability rc)
1705 if (!rc.IsUnreachable) {
1706 var label = switch_statement.FindLabel ((Constant) expr);
1707 if (label.IsUnreachable) {
1708 label.MarkReachable (rc);
1709 switch_statement.Block.ScanGotoJump (label);
1713 return base.MarkReachable (rc);
1716 public override object Accept (StructuralVisitor visitor)
1718 return visitor.Visit (this);
1722 public abstract class SwitchGoto : Statement
1724 protected bool unwind_protect;
1725 protected Switch switch_statement;
1727 protected SwitchGoto (Location loc)
1732 protected override void CloneTo (CloneContext clonectx, Statement target)
1737 public override bool Resolve (BlockContext bc)
1739 CheckExitBoundaries (bc, bc.Switch.Block);
1741 unwind_protect = bc.HasAny (ResolveContext.Options.TryScope | ResolveContext.Options.CatchScope);
1742 switch_statement = bc.Switch;
1747 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1752 public override Reachability MarkReachable (Reachability rc)
1754 base.MarkReachable (rc);
1755 return Reachability.CreateUnreachable ();
1758 protected void Error_GotoCaseRequiresSwitchBlock (BlockContext bc)
1760 bc.Report.Error (153, loc, "A goto case is only valid inside a switch statement");
1764 public class Throw : Statement {
1767 public Throw (Expression expr, Location l)
1773 public Expression Expr {
1779 public override bool Resolve (BlockContext ec)
1782 if (!ec.HasSet (ResolveContext.Options.CatchScope)) {
1783 ec.Report.Error (156, loc, "A throw statement with no arguments is not allowed outside of a catch clause");
1784 } else if (ec.HasSet (ResolveContext.Options.FinallyScope)) {
1785 for (var b = ec.CurrentBlock; b != null && !b.IsCatchBlock; b = b.Parent) {
1786 if (b.IsFinallyBlock) {
1787 ec.Report.Error (724, loc,
1788 "A throw statement with no arguments is not allowed inside of a finally clause nested inside of the innermost catch clause");
1797 expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
1802 var et = ec.BuiltinTypes.Exception;
1803 if (Convert.ImplicitConversionExists (ec, expr, et))
1804 expr = Convert.ImplicitConversion (ec, expr, et, loc);
1806 ec.Report.Error (155, expr.Location, "The type caught or thrown must be derived from System.Exception");
1811 protected override void DoEmit (EmitContext ec)
1814 var atv = ec.AsyncThrowVariable;
1816 if (atv.HoistedVariant != null) {
1817 atv.HoistedVariant.Emit (ec);
1822 ec.Emit (OpCodes.Throw);
1824 ec.Emit (OpCodes.Rethrow);
1829 ec.Emit (OpCodes.Throw);
1833 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1836 expr.FlowAnalysis (fc);
1841 public override Reachability MarkReachable (Reachability rc)
1843 base.MarkReachable (rc);
1844 return Reachability.CreateUnreachable ();
1847 protected override void CloneTo (CloneContext clonectx, Statement t)
1849 Throw target = (Throw) t;
1852 target.expr = expr.Clone (clonectx);
1855 public override object Accept (StructuralVisitor visitor)
1857 return visitor.Visit (this);
1861 public class Break : LocalExitStatement
1863 public Break (Location l)
1868 public override object Accept (StructuralVisitor visitor)
1870 return visitor.Visit (this);
1873 protected override void DoEmit (EmitContext ec)
1877 if (ec.TryFinallyUnwind != null) {
1878 var async_body = (AsyncInitializer) ec.CurrentAnonymousMethod;
1879 l = TryFinally.EmitRedirectedJump (ec, async_body, l, enclosing_loop.Statement as Block);
1882 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, l);
1885 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1887 enclosing_loop.AddEndDefiniteAssignment (fc);
1891 protected override bool DoResolve (BlockContext bc)
1893 enclosing_loop = bc.EnclosingLoopOrSwitch;
1894 return base.DoResolve (bc);
1897 public override Reachability MarkReachable (Reachability rc)
1899 base.MarkReachable (rc);
1901 if (!rc.IsUnreachable)
1902 enclosing_loop.SetEndReachable ();
1904 return Reachability.CreateUnreachable ();
1908 public class Continue : LocalExitStatement
1910 public Continue (Location l)
1915 public override object Accept (StructuralVisitor visitor)
1917 return visitor.Visit (this);
1921 protected override void DoEmit (EmitContext ec)
1923 var l = ec.LoopBegin;
1925 if (ec.TryFinallyUnwind != null) {
1926 var async_body = (AsyncInitializer) ec.CurrentAnonymousMethod;
1927 l = TryFinally.EmitRedirectedJump (ec, async_body, l, enclosing_loop.Statement as Block);
1930 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, l);
1933 protected override bool DoResolve (BlockContext bc)
1935 enclosing_loop = bc.EnclosingLoop;
1936 return base.DoResolve (bc);
1939 public override Reachability MarkReachable (Reachability rc)
1941 base.MarkReachable (rc);
1943 if (!rc.IsUnreachable)
1944 enclosing_loop.SetIteratorReachable ();
1946 return Reachability.CreateUnreachable ();
1950 public abstract class LocalExitStatement : ExitStatement
1952 protected LoopStatement enclosing_loop;
1954 protected LocalExitStatement (Location loc)
1959 protected override bool IsLocalExit {
1965 protected override void CloneTo (CloneContext clonectx, Statement t)
1970 protected override bool DoResolve (BlockContext bc)
1972 if (enclosing_loop == null) {
1973 bc.Report.Error (139, loc, "No enclosing loop out of which to break or continue");
1977 var block = enclosing_loop.Statement as Block;
1979 // Don't need to do extra checks for simple statements loops
1980 if (block != null) {
1981 CheckExitBoundaries (bc, block);
1988 public interface ILocalVariable
1990 void Emit (EmitContext ec);
1991 void EmitAssign (EmitContext ec);
1992 void EmitAddressOf (EmitContext ec);
1995 public interface INamedBlockVariable
1997 Block Block { get; }
1998 Expression CreateReferenceExpression (ResolveContext rc, Location loc);
1999 bool IsDeclared { get; }
2000 bool IsParameter { get; }
2001 Location Location { get; }
2004 public class BlockVariableDeclarator
2007 Expression initializer;
2009 public BlockVariableDeclarator (LocalVariable li, Expression initializer)
2011 if (li.Type != null)
2012 throw new ArgumentException ("Expected null variable type");
2015 this.initializer = initializer;
2020 public LocalVariable Variable {
2026 public Expression Initializer {
2031 initializer = value;
2037 public virtual BlockVariableDeclarator Clone (CloneContext cloneCtx)
2039 var t = (BlockVariableDeclarator) MemberwiseClone ();
2040 if (initializer != null)
2041 t.initializer = initializer.Clone (cloneCtx);
2047 public class BlockVariable : Statement
2049 Expression initializer;
2050 protected FullNamedExpression type_expr;
2051 protected LocalVariable li;
2052 protected List<BlockVariableDeclarator> declarators;
2055 public BlockVariable (FullNamedExpression type, LocalVariable li)
2057 this.type_expr = type;
2059 this.loc = type_expr.Location;
2062 protected BlockVariable (LocalVariable li)
2069 public List<BlockVariableDeclarator> Declarators {
2075 public Expression Initializer {
2080 initializer = value;
2084 public FullNamedExpression TypeExpression {
2090 public LocalVariable Variable {
2098 public void AddDeclarator (BlockVariableDeclarator decl)
2100 if (declarators == null)
2101 declarators = new List<BlockVariableDeclarator> ();
2103 declarators.Add (decl);
2106 static void CreateEvaluatorVariable (BlockContext bc, LocalVariable li)
2108 if (bc.Report.Errors != 0)
2111 var container = bc.CurrentMemberDefinition.Parent.PartialContainer;
2113 Field f = new Field (container, new TypeExpression (li.Type, li.Location), Modifiers.PUBLIC | Modifiers.STATIC,
2114 new MemberName (li.Name, li.Location), null);
2116 container.AddField (f);
2119 li.HoistedVariant = new HoistedEvaluatorVariable (f);
2123 public override bool Resolve (BlockContext bc)
2125 return Resolve (bc, true);
2128 public bool Resolve (BlockContext bc, bool resolveDeclaratorInitializers)
2130 if (type == null && !li.IsCompilerGenerated) {
2131 var vexpr = type_expr as VarExpr;
2134 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
2135 // same name exists or as a keyword when no type was found
2137 if (vexpr != null && !vexpr.IsPossibleTypeOrNamespace (bc)) {
2138 if (bc.Module.Compiler.Settings.Version < LanguageVersion.V_3)
2139 bc.Report.FeatureIsNotAvailable (bc.Module.Compiler, loc, "implicitly typed local variable");
2142 bc.Report.Error (821, loc, "A fixed statement cannot use an implicitly typed local variable");
2146 if (li.IsConstant) {
2147 bc.Report.Error (822, loc, "An implicitly typed local variable cannot be a constant");
2151 if (Initializer == null) {
2152 bc.Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
2156 if (declarators != null) {
2157 bc.Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
2161 Initializer = Initializer.Resolve (bc);
2162 if (Initializer != null) {
2163 ((VarExpr) type_expr).InferType (bc, Initializer);
2164 type = type_expr.Type;
2166 // Set error type to indicate the var was placed correctly but could
2169 // var a = missing ();
2171 type = InternalType.ErrorType;
2176 type = type_expr.ResolveAsType (bc);
2180 if (li.IsConstant && !type.IsConstantCompatible) {
2181 Const.Error_InvalidConstantType (type, loc, bc.Report);
2186 FieldBase.Error_VariableOfStaticClass (loc, li.Name, type, bc.Report);
2191 bool eval_global = bc.Module.Compiler.Settings.StatementMode && bc.CurrentBlock is ToplevelBlock;
2193 CreateEvaluatorVariable (bc, li);
2194 } else if (type != InternalType.ErrorType) {
2195 li.PrepareAssignmentAnalysis (bc);
2198 if (initializer != null) {
2199 initializer = ResolveInitializer (bc, li, initializer);
2200 // li.Variable.DefinitelyAssigned
2203 if (declarators != null) {
2204 foreach (var d in declarators) {
2205 d.Variable.Type = li.Type;
2207 CreateEvaluatorVariable (bc, d.Variable);
2208 } else if (type != InternalType.ErrorType) {
2209 d.Variable.PrepareAssignmentAnalysis (bc);
2212 if (d.Initializer != null && resolveDeclaratorInitializers) {
2213 d.Initializer = ResolveInitializer (bc, d.Variable, d.Initializer);
2214 // d.Variable.DefinitelyAssigned
2222 protected virtual Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
2224 var a = new SimpleAssign (li.CreateReferenceExpression (bc, li.Location), initializer, li.Location);
2225 return a.ResolveStatement (bc);
2228 protected override void DoEmit (EmitContext ec)
2230 li.CreateBuilder (ec);
2232 if (Initializer != null && !IsUnreachable)
2233 ((ExpressionStatement) Initializer).EmitStatement (ec);
2235 if (declarators != null) {
2236 foreach (var d in declarators) {
2237 d.Variable.CreateBuilder (ec);
2238 if (d.Initializer != null && !IsUnreachable) {
2239 ec.Mark (d.Variable.Location);
2240 ((ExpressionStatement) d.Initializer).EmitStatement (ec);
2246 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
2248 if (Initializer != null)
2249 Initializer.FlowAnalysis (fc);
2251 if (declarators != null) {
2252 foreach (var d in declarators) {
2253 if (d.Initializer != null)
2254 d.Initializer.FlowAnalysis (fc);
2261 public override Reachability MarkReachable (Reachability rc)
2263 var init = initializer as ExpressionStatement;
2265 init.MarkReachable (rc);
2267 return base.MarkReachable (rc);
2270 protected override void CloneTo (CloneContext clonectx, Statement target)
2272 BlockVariable t = (BlockVariable) target;
2274 if (type_expr != null)
2275 t.type_expr = (FullNamedExpression) type_expr.Clone (clonectx);
2277 if (initializer != null)
2278 t.initializer = initializer.Clone (clonectx);
2280 if (declarators != null) {
2281 t.declarators = null;
2282 foreach (var d in declarators)
2283 t.AddDeclarator (d.Clone (clonectx));
2287 public override object Accept (StructuralVisitor visitor)
2289 return visitor.Visit (this);
2293 public class BlockConstant : BlockVariable
2295 public BlockConstant (FullNamedExpression type, LocalVariable li)
2300 public override void Emit (EmitContext ec)
2302 // Nothing to emit, not even sequence point
2305 protected override Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
2307 initializer = initializer.Resolve (bc);
2308 if (initializer == null)
2311 var c = initializer as Constant;
2313 initializer.Error_ExpressionMustBeConstant (bc, initializer.Location, li.Name);
2317 c = c.ConvertImplicitly (li.Type);
2319 if (TypeSpec.IsReferenceType (li.Type))
2320 initializer.Error_ConstantCanBeInitializedWithNullOnly (bc, li.Type, initializer.Location, li.Name);
2322 initializer.Error_ValueCannotBeConverted (bc, li.Type, false);
2327 li.ConstantValue = c;
2331 public override object Accept (StructuralVisitor visitor)
2333 return visitor.Visit (this);
2338 // The information about a user-perceived local variable
2340 public sealed class LocalVariable : INamedBlockVariable, ILocalVariable
2347 AddressTaken = 1 << 2,
2348 CompilerGenerated = 1 << 3,
2350 ForeachVariable = 1 << 5,
2351 FixedVariable = 1 << 6,
2352 UsingVariable = 1 << 7,
2355 ReadonlyMask = ForeachVariable | FixedVariable | UsingVariable
2359 readonly string name;
2360 readonly Location loc;
2361 readonly Block block;
2363 Constant const_value;
2365 public VariableInfo VariableInfo;
2366 HoistedVariable hoisted_variant;
2368 LocalBuilder builder;
2370 public LocalVariable (Block block, string name, Location loc)
2377 public LocalVariable (Block block, string name, Flags flags, Location loc)
2378 : this (block, name, loc)
2384 // Used by variable declarators
2386 public LocalVariable (LocalVariable li, string name, Location loc)
2387 : this (li.block, name, li.flags, loc)
2393 public bool AddressTaken {
2395 return (flags & Flags.AddressTaken) != 0;
2399 public Block Block {
2405 public Constant ConstantValue {
2410 const_value = value;
2415 // Hoisted local variable variant
2417 public HoistedVariable HoistedVariant {
2419 return hoisted_variant;
2422 hoisted_variant = value;
2426 public bool IsDeclared {
2428 return type != null;
2432 public bool IsCompilerGenerated {
2434 return (flags & Flags.CompilerGenerated) != 0;
2438 public bool IsConstant {
2440 return (flags & Flags.Constant) != 0;
2444 public bool IsLocked {
2446 return (flags & Flags.IsLocked) != 0;
2449 flags = value ? flags | Flags.IsLocked : flags & ~Flags.IsLocked;
2453 public bool IsThis {
2455 return (flags & Flags.IsThis) != 0;
2459 public bool IsFixed {
2461 return (flags & Flags.FixedVariable) != 0;
2465 bool INamedBlockVariable.IsParameter {
2471 public bool IsReadonly {
2473 return (flags & Flags.ReadonlyMask) != 0;
2477 public Location Location {
2483 public string Name {
2489 public TypeSpec Type {
2500 public void CreateBuilder (EmitContext ec)
2502 if ((flags & Flags.Used) == 0) {
2503 if (VariableInfo == null) {
2504 // Missing flow analysis or wrong variable flags
2505 throw new InternalErrorException ("VariableInfo is null and the variable `{0}' is not used", name);
2508 if (VariableInfo.IsEverAssigned)
2509 ec.Report.Warning (219, 3, Location, "The variable `{0}' is assigned but its value is never used", Name);
2511 ec.Report.Warning (168, 3, Location, "The variable `{0}' is declared but never used", Name);
2514 if (HoistedVariant != null)
2517 if (builder != null) {
2518 if ((flags & Flags.CompilerGenerated) != 0)
2521 // To avoid Used warning duplicates
2522 throw new InternalErrorException ("Already created variable `{0}'", name);
2526 // All fixed variabled are pinned, a slot has to be alocated
2528 builder = ec.DeclareLocal (Type, IsFixed);
2529 if (!ec.HasSet (BuilderContext.Options.OmitDebugInfo) && (flags & Flags.CompilerGenerated) == 0)
2530 ec.DefineLocalVariable (name, builder);
2533 public static LocalVariable CreateCompilerGenerated (TypeSpec type, Block block, Location loc)
2535 LocalVariable li = new LocalVariable (block, GetCompilerGeneratedName (block), Flags.CompilerGenerated | Flags.Used, loc);
2540 public Expression CreateReferenceExpression (ResolveContext rc, Location loc)
2542 if (IsConstant && const_value != null)
2543 return Constant.CreateConstantFromValue (Type, const_value.GetValue (), loc);
2545 return new LocalVariableReference (this, loc);
2548 public void Emit (EmitContext ec)
2550 // TODO: Need something better for temporary variables
2551 if ((flags & Flags.CompilerGenerated) != 0)
2554 ec.Emit (OpCodes.Ldloc, builder);
2557 public void EmitAssign (EmitContext ec)
2559 // TODO: Need something better for temporary variables
2560 if ((flags & Flags.CompilerGenerated) != 0)
2563 ec.Emit (OpCodes.Stloc, builder);
2566 public void EmitAddressOf (EmitContext ec)
2568 // TODO: Need something better for temporary variables
2569 if ((flags & Flags.CompilerGenerated) != 0)
2572 ec.Emit (OpCodes.Ldloca, builder);
2575 public static string GetCompilerGeneratedName (Block block)
2577 // HACK: Debugger depends on the name semantics
2578 return "$locvar" + block.ParametersBlock.TemporaryLocalsCount++.ToString ("X");
2581 public string GetReadOnlyContext ()
2583 switch (flags & Flags.ReadonlyMask) {
2584 case Flags.FixedVariable:
2585 return "fixed variable";
2586 case Flags.ForeachVariable:
2587 return "foreach iteration variable";
2588 case Flags.UsingVariable:
2589 return "using variable";
2592 throw new InternalErrorException ("Variable is not readonly");
2595 public bool IsThisAssigned (FlowAnalysisContext fc, Block block)
2597 if (VariableInfo == null)
2598 throw new Exception ();
2600 if (IsAssigned (fc))
2603 return VariableInfo.IsFullyInitialized (fc, block.StartLocation);
2606 public bool IsAssigned (FlowAnalysisContext fc)
2608 return fc.IsDefinitelyAssigned (VariableInfo);
2611 public void PrepareAssignmentAnalysis (BlockContext bc)
2614 // No need to run assignment analysis for these guys
2616 if ((flags & (Flags.Constant | Flags.ReadonlyMask | Flags.CompilerGenerated)) != 0)
2619 VariableInfo = VariableInfo.Create (bc, this);
2623 // Mark the variables as referenced in the user code
2625 public void SetIsUsed ()
2627 flags |= Flags.Used;
2630 public void SetHasAddressTaken ()
2632 flags |= (Flags.AddressTaken | Flags.Used);
2635 public override string ToString ()
2637 return string.Format ("LocalInfo ({0},{1},{2},{3})", name, type, VariableInfo, Location);
2642 /// Block represents a C# block.
2646 /// This class is used in a number of places: either to represent
2647 /// explicit blocks that the programmer places or implicit blocks.
2649 /// Implicit blocks are used as labels or to introduce variable
2652 /// Top-level blocks derive from Block, and they are called ToplevelBlock
2653 /// they contain extra information that is not necessary on normal blocks.
2655 public class Block : Statement {
2662 HasCapturedVariable = 64,
2663 HasCapturedThis = 1 << 7,
2664 IsExpressionTree = 1 << 8,
2665 CompilerGenerated = 1 << 9,
2666 HasAsyncModifier = 1 << 10,
2668 YieldBlock = 1 << 12,
2669 AwaitBlock = 1 << 13,
2670 FinallyBlock = 1 << 14,
2671 CatchBlock = 1 << 15,
2673 NoFlowAnalysis = 1 << 21,
2674 InitializationEmitted = 1 << 22
2677 public Block Parent;
2678 public Location StartLocation;
2679 public Location EndLocation;
2681 public ExplicitBlock Explicit;
2682 public ParametersBlock ParametersBlock;
2684 protected Flags flags;
2687 // The statements in this block
2689 protected List<Statement> statements;
2691 protected List<Statement> scope_initializers;
2693 int? resolving_init_idx;
2699 public int ID = id++;
2701 static int clone_id_counter;
2705 // int assignable_slots;
2707 public Block (Block parent, Location start, Location end)
2708 : this (parent, 0, start, end)
2712 public Block (Block parent, Flags flags, Location start, Location end)
2714 if (parent != null) {
2715 // the appropriate constructors will fixup these fields
2716 ParametersBlock = parent.ParametersBlock;
2717 Explicit = parent.Explicit;
2720 this.Parent = parent;
2722 this.StartLocation = start;
2723 this.EndLocation = end;
2725 statements = new List<Statement> (4);
2727 this.original = this;
2732 public Block Original {
2741 public bool IsCompilerGenerated {
2742 get { return (flags & Flags.CompilerGenerated) != 0; }
2743 set { flags = value ? flags | Flags.CompilerGenerated : flags & ~Flags.CompilerGenerated; }
2747 public bool IsCatchBlock {
2749 return (flags & Flags.CatchBlock) != 0;
2753 public bool IsFinallyBlock {
2755 return (flags & Flags.FinallyBlock) != 0;
2759 public bool Unchecked {
2760 get { return (flags & Flags.Unchecked) != 0; }
2761 set { flags = value ? flags | Flags.Unchecked : flags & ~Flags.Unchecked; }
2764 public bool Unsafe {
2765 get { return (flags & Flags.Unsafe) != 0; }
2766 set { flags |= Flags.Unsafe; }
2769 public List<Statement> Statements {
2770 get { return statements; }
2775 public void SetEndLocation (Location loc)
2780 public void AddLabel (LabeledStatement target)
2782 ParametersBlock.TopBlock.AddLabel (target.Name, target);
2785 public void AddLocalName (LocalVariable li)
2787 AddLocalName (li.Name, li);
2790 public void AddLocalName (string name, INamedBlockVariable li)
2792 ParametersBlock.TopBlock.AddLocalName (name, li, false);
2795 public virtual void Error_AlreadyDeclared (string name, INamedBlockVariable variable, string reason)
2797 if (reason == null) {
2798 Error_AlreadyDeclared (name, variable);
2802 ParametersBlock.TopBlock.Report.Error (136, variable.Location,
2803 "A local variable named `{0}' cannot be declared in this scope because it would give a different meaning " +
2804 "to `{0}', which is already used in a `{1}' scope to denote something else",
2808 public virtual void Error_AlreadyDeclared (string name, INamedBlockVariable variable)
2810 var pi = variable as ParametersBlock.ParameterInfo;
2812 pi.Parameter.Error_DuplicateName (ParametersBlock.TopBlock.Report);
2814 ParametersBlock.TopBlock.Report.Error (128, variable.Location,
2815 "A local variable named `{0}' is already defined in this scope", name);
2819 public virtual void Error_AlreadyDeclaredTypeParameter (string name, Location loc)
2821 ParametersBlock.TopBlock.Report.Error (412, loc,
2822 "The type parameter name `{0}' is the same as local variable or parameter name",
2827 // It should be used by expressions which require to
2828 // register a statement during resolve process.
2830 public void AddScopeStatement (Statement s)
2832 if (scope_initializers == null)
2833 scope_initializers = new List<Statement> ();
2836 // Simple recursive helper, when resolve scope initializer another
2837 // new scope initializer can be added, this ensures it's initialized
2838 // before existing one. For now this can happen with expression trees
2839 // in base ctor initializer only
2841 if (resolving_init_idx.HasValue) {
2842 scope_initializers.Insert (resolving_init_idx.Value, s);
2843 ++resolving_init_idx;
2845 scope_initializers.Add (s);
2849 public void InsertStatement (int index, Statement s)
2851 statements.Insert (index, s);
2854 public void AddStatement (Statement s)
2859 public LabeledStatement LookupLabel (string name)
2861 return ParametersBlock.GetLabel (name, this);
2864 public override Reachability MarkReachable (Reachability rc)
2866 if (rc.IsUnreachable)
2869 MarkReachableScope (rc);
2871 foreach (var s in statements) {
2872 rc = s.MarkReachable (rc);
2873 if (rc.IsUnreachable) {
2874 if ((flags & Flags.ReachableEnd) != 0)
2875 return new Reachability ();
2881 flags |= Flags.ReachableEnd;
2886 public void MarkReachableScope (Reachability rc)
2888 base.MarkReachable (rc);
2890 if (scope_initializers != null) {
2891 foreach (var si in scope_initializers)
2892 si.MarkReachable (rc);
2896 public override bool Resolve (BlockContext bc)
2898 if ((flags & Flags.Resolved) != 0)
2901 Block prev_block = bc.CurrentBlock;
2902 bc.CurrentBlock = this;
2905 // Compiler generated scope statements
2907 if (scope_initializers != null) {
2908 for (resolving_init_idx = 0; resolving_init_idx < scope_initializers.Count; ++resolving_init_idx) {
2909 scope_initializers[resolving_init_idx.Value].Resolve (bc);
2912 resolving_init_idx = null;
2916 int statement_count = statements.Count;
2917 for (int ix = 0; ix < statement_count; ix++){
2918 Statement s = statements [ix];
2920 if (!s.Resolve (bc)) {
2922 if (!bc.IsInProbingMode)
2923 statements [ix] = new EmptyStatement (s.loc);
2929 bc.CurrentBlock = prev_block;
2931 flags |= Flags.Resolved;
2935 protected override void DoEmit (EmitContext ec)
2937 for (int ix = 0; ix < statements.Count; ix++){
2938 statements [ix].Emit (ec);
2942 public override void Emit (EmitContext ec)
2944 if (scope_initializers != null)
2945 EmitScopeInitializers (ec);
2950 protected void EmitScopeInitializers (EmitContext ec)
2952 foreach (Statement s in scope_initializers)
2956 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
2958 if (scope_initializers != null) {
2959 foreach (var si in scope_initializers)
2960 si.FlowAnalysis (fc);
2963 return DoFlowAnalysis (fc, 0);
2966 bool DoFlowAnalysis (FlowAnalysisContext fc, int startIndex)
2968 bool end_unreachable = !reachable;
2969 for (; startIndex < statements.Count; ++startIndex) {
2970 var s = statements[startIndex];
2972 end_unreachable = s.FlowAnalysis (fc);
2973 if (s.IsUnreachable) {
2974 statements [startIndex] = RewriteUnreachableStatement (s);
2979 // Statement end reachability is needed mostly due to goto support. Consider
2988 // X label is reachable only via goto not as another statement after if. We need
2989 // this for flow-analysis only to carry variable info correctly.
2991 if (end_unreachable) {
2992 for (++startIndex; startIndex < statements.Count; ++startIndex) {
2993 s = statements[startIndex];
2994 if (s is SwitchLabel) {
2995 s.FlowAnalysis (fc);
2999 if (s.IsUnreachable) {
3000 s.FlowAnalysis (fc);
3001 statements [startIndex] = RewriteUnreachableStatement (s);
3008 // The condition should be true unless there is forward jumping goto
3010 // if (this is ExplicitBlock && end_unreachable != Explicit.HasReachableClosingBrace)
3013 return !Explicit.HasReachableClosingBrace;
3016 static Statement RewriteUnreachableStatement (Statement s)
3018 // LAMESPEC: It's not clear whether declararion statement should be part of reachability
3019 // analysis. Even csc report unreachable warning for it but it's actually used hence
3020 // we try to emulate this behaviour
3028 if (s is BlockVariable)
3031 return new EmptyStatement (s.loc);
3034 public void ScanGotoJump (Statement label)
3037 for (i = 0; i < statements.Count; ++i) {
3038 if (statements[i] == label)
3042 var rc = new Reachability ();
3043 for (++i; i < statements.Count; ++i) {
3044 var s = statements[i];
3045 rc = s.MarkReachable (rc);
3046 if (rc.IsUnreachable)
3050 flags |= Flags.ReachableEnd;
3053 public void ScanGotoJump (Statement label, FlowAnalysisContext fc)
3056 for (i = 0; i < statements.Count; ++i) {
3057 if (statements[i] == label)
3061 DoFlowAnalysis (fc, ++i);
3065 public override string ToString ()
3067 return String.Format ("{0}: ID={1} Clone={2} Location={3}", GetType (), ID, clone_id != 0, StartLocation);
3071 protected override void CloneTo (CloneContext clonectx, Statement t)
3073 Block target = (Block) t;
3075 target.clone_id = ++clone_id_counter;
3078 clonectx.AddBlockMap (this, target);
3079 if (original != this)
3080 clonectx.AddBlockMap (original, target);
3082 target.ParametersBlock = (ParametersBlock) (ParametersBlock == this ? target : clonectx.RemapBlockCopy (ParametersBlock));
3083 target.Explicit = (ExplicitBlock) (Explicit == this ? target : clonectx.LookupBlock (Explicit));
3086 target.Parent = clonectx.RemapBlockCopy (Parent);
3088 target.statements = new List<Statement> (statements.Count);
3089 foreach (Statement s in statements)
3090 target.statements.Add (s.Clone (clonectx));
3093 public override object Accept (StructuralVisitor visitor)
3095 return visitor.Visit (this);
3099 public class ExplicitBlock : Block
3101 protected AnonymousMethodStorey am_storey;
3103 public ExplicitBlock (Block parent, Location start, Location end)
3104 : this (parent, (Flags) 0, start, end)
3108 public ExplicitBlock (Block parent, Flags flags, Location start, Location end)
3109 : base (parent, flags, start, end)
3111 this.Explicit = this;
3116 public AnonymousMethodStorey AnonymousMethodStorey {
3122 public bool HasAwait {
3124 return (flags & Flags.AwaitBlock) != 0;
3128 public bool HasCapturedThis {
3130 flags = value ? flags | Flags.HasCapturedThis : flags & ~Flags.HasCapturedThis;
3133 return (flags & Flags.HasCapturedThis) != 0;
3138 // Used to indicate that the block has reference to parent
3139 // block and cannot be made static when defining anonymous method
3141 public bool HasCapturedVariable {
3143 flags = value ? flags | Flags.HasCapturedVariable : flags & ~Flags.HasCapturedVariable;
3146 return (flags & Flags.HasCapturedVariable) != 0;
3150 public bool HasReachableClosingBrace {
3152 return (flags & Flags.ReachableEnd) != 0;
3155 flags = value ? flags | Flags.ReachableEnd : flags & ~Flags.ReachableEnd;
3159 public bool HasYield {
3161 return (flags & Flags.YieldBlock) != 0;
3168 // Creates anonymous method storey in current block
3170 public AnonymousMethodStorey CreateAnonymousMethodStorey (ResolveContext ec)
3173 // Return same story for iterator and async blocks unless we are
3174 // in nested anonymous method
3176 if (ec.CurrentAnonymousMethod is StateMachineInitializer && ParametersBlock.Original == ec.CurrentAnonymousMethod.Block.Original)
3177 return ec.CurrentAnonymousMethod.Storey;
3179 if (am_storey == null) {
3180 MemberBase mc = ec.MemberContext as MemberBase;
3183 // Creates anonymous method storey for this block
3185 am_storey = new AnonymousMethodStorey (this, ec.CurrentMemberDefinition.Parent.PartialContainer, mc, ec.CurrentTypeParameters, "AnonStorey", MemberKind.Class);
3191 public void EmitScopeInitialization (EmitContext ec)
3193 if ((flags & Flags.InitializationEmitted) != 0)
3196 if (am_storey != null) {
3197 DefineStoreyContainer (ec, am_storey);
3198 am_storey.EmitStoreyInstantiation (ec, this);
3201 if (scope_initializers != null)
3202 EmitScopeInitializers (ec);
3204 flags |= Flags.InitializationEmitted;
3207 public override void Emit (EmitContext ec)
3209 EmitScopeInitialization (ec);
3211 if (ec.EmitAccurateDebugInfo && !IsCompilerGenerated && ec.Mark (StartLocation)) {
3212 ec.Emit (OpCodes.Nop);
3223 if (ec.EmitAccurateDebugInfo && HasReachableClosingBrace && !(this is ParametersBlock) &&
3224 !IsCompilerGenerated && ec.Mark (EndLocation)) {
3225 ec.Emit (OpCodes.Nop);
3229 protected void DefineStoreyContainer (EmitContext ec, AnonymousMethodStorey storey)
3231 if (ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.Storey != null) {
3232 storey.SetNestedStoryParent (ec.CurrentAnonymousMethod.Storey);
3233 storey.Mutator = ec.CurrentAnonymousMethod.Storey.Mutator;
3237 // Creates anonymous method storey
3239 storey.CreateContainer ();
3240 storey.DefineContainer ();
3242 if (Original.Explicit.HasCapturedThis && Original.ParametersBlock.TopBlock.ThisReferencesFromChildrenBlock != null) {
3245 // Only first storey in path will hold this reference. All children blocks will
3246 // reference it indirectly using $ref field
3248 for (Block b = Original.Explicit; b != null; b = b.Parent) {
3249 if (b.Parent != null) {
3250 var s = b.Parent.Explicit.AnonymousMethodStorey;
3252 storey.HoistedThis = s.HoistedThis;
3257 if (b.Explicit == b.Explicit.ParametersBlock && b.Explicit.ParametersBlock.StateMachine != null) {
3258 if (storey.HoistedThis == null)
3259 storey.HoistedThis = b.Explicit.ParametersBlock.StateMachine.HoistedThis;
3261 if (storey.HoistedThis != null)
3267 // We are the first storey on path and 'this' has to be hoisted
3269 if (storey.HoistedThis == null) {
3270 foreach (ExplicitBlock ref_block in Original.ParametersBlock.TopBlock.ThisReferencesFromChildrenBlock) {
3272 // ThisReferencesFromChildrenBlock holds all reference even if they
3273 // are not on this path. It saves some memory otherwise it'd have to
3274 // be in every explicit block. We run this check to see if the reference
3275 // is valid for this storey
3277 Block block_on_path = ref_block;
3278 for (; block_on_path != null && block_on_path != Original; block_on_path = block_on_path.Parent);
3280 if (block_on_path == null)
3283 if (storey.HoistedThis == null) {
3284 storey.AddCapturedThisField (ec, null);
3287 for (ExplicitBlock b = ref_block; b.AnonymousMethodStorey != storey; b = b.Parent.Explicit) {
3289 AnonymousMethodStorey b_storey = b.AnonymousMethodStorey;
3291 if (b_storey != null) {
3293 // Don't add storey cross reference for `this' when the storey ends up not
3294 // beeing attached to any parent
3296 if (b.ParametersBlock.StateMachine == null) {
3297 AnonymousMethodStorey s = null;
3298 for (Block ab = b.AnonymousMethodStorey.OriginalSourceBlock.Parent; ab != null; ab = ab.Parent) {
3299 s = ab.Explicit.AnonymousMethodStorey;
3304 // Needs to be in sync with AnonymousMethodBody::DoCreateMethodHost
3306 var parent = storey == null || storey.Kind == MemberKind.Struct ? null : storey;
3307 b.AnonymousMethodStorey.AddCapturedThisField (ec, parent);
3314 // Stop propagation inside same top block
3316 if (b.ParametersBlock == ParametersBlock.Original) {
3317 b_storey.AddParentStoreyReference (ec, storey);
3318 // b_storey.HoistedThis = storey.HoistedThis;
3322 b = pb = b.ParametersBlock;
3324 pb = b as ParametersBlock;
3327 if (pb != null && pb.StateMachine != null) {
3328 if (pb.StateMachine == storey)
3332 // If we are state machine with no parent. We can hook into parent without additional
3333 // reference and capture this directly
3335 ExplicitBlock parent_storey_block = pb;
3336 while (parent_storey_block.Parent != null) {
3337 parent_storey_block = parent_storey_block.Parent.Explicit;
3338 if (parent_storey_block.AnonymousMethodStorey != null) {
3343 if (parent_storey_block.AnonymousMethodStorey == null) {
3344 pb.StateMachine.AddCapturedThisField (ec, null);
3345 b.HasCapturedThis = true;
3349 pb.StateMachine.AddParentStoreyReference (ec, storey);
3353 // Add parent storey reference only when this is not captured directly
3355 if (b_storey != null) {
3356 b_storey.AddParentStoreyReference (ec, storey);
3357 b_storey.HoistedThis = storey.HoistedThis;
3364 var ref_blocks = storey.ReferencesFromChildrenBlock;
3365 if (ref_blocks != null) {
3366 foreach (ExplicitBlock ref_block in ref_blocks) {
3367 for (ExplicitBlock b = ref_block; b.AnonymousMethodStorey != storey; b = b.Parent.Explicit) {
3368 if (b.AnonymousMethodStorey != null) {
3369 b.AnonymousMethodStorey.AddParentStoreyReference (ec, storey);
3372 // Stop propagation inside same top block
3374 if (b.ParametersBlock == ParametersBlock.Original)
3377 b = b.ParametersBlock;
3380 var pb = b as ParametersBlock;
3381 if (pb != null && pb.StateMachine != null) {
3382 if (pb.StateMachine == storey)
3385 pb.StateMachine.AddParentStoreyReference (ec, storey);
3388 b.HasCapturedVariable = true;
3394 storey.PrepareEmit ();
3395 storey.Parent.PartialContainer.AddCompilerGeneratedClass (storey);
3398 public void RegisterAsyncAwait ()
3401 while ((block.flags & Flags.AwaitBlock) == 0) {
3402 block.flags |= Flags.AwaitBlock;
3404 if (block is ParametersBlock)
3407 block = block.Parent.Explicit;
3411 public void RegisterIteratorYield ()
3413 ParametersBlock.TopBlock.IsIterator = true;
3416 while ((block.flags & Flags.YieldBlock) == 0) {
3417 block.flags |= Flags.YieldBlock;
3419 if (block.Parent == null)
3422 block = block.Parent.Explicit;
3426 public void SetCatchBlock ()
3428 flags |= Flags.CatchBlock;
3431 public void SetFinallyBlock ()
3433 flags |= Flags.FinallyBlock;
3436 public void WrapIntoDestructor (TryFinally tf, ExplicitBlock tryBlock)
3438 tryBlock.statements = statements;
3439 statements = new List<Statement> (1);
3440 statements.Add (tf);
3445 // ParametersBlock was introduced to support anonymous methods
3446 // and lambda expressions
3448 public class ParametersBlock : ExplicitBlock
3450 public class ParameterInfo : INamedBlockVariable
3452 readonly ParametersBlock block;
3454 public VariableInfo VariableInfo;
3457 public ParameterInfo (ParametersBlock block, int index)
3465 public ParametersBlock Block {
3471 Block INamedBlockVariable.Block {
3477 public bool IsDeclared {
3483 public bool IsParameter {
3489 public bool IsLocked {
3498 public Location Location {
3500 return Parameter.Location;
3504 public Parameter Parameter {
3506 return block.Parameters [index];
3510 public TypeSpec ParameterType {
3512 return Parameter.Type;
3518 public Expression CreateReferenceExpression (ResolveContext rc, Location loc)
3520 return new ParameterReference (this, loc);
3525 // Block is converted into an expression
3527 sealed class BlockScopeExpression : Expression
3530 readonly ParametersBlock block;
3532 public BlockScopeExpression (Expression child, ParametersBlock block)
3538 public override bool ContainsEmitWithAwait ()
3540 return child.ContainsEmitWithAwait ();
3543 public override Expression CreateExpressionTree (ResolveContext ec)
3545 throw new NotSupportedException ();
3548 protected override Expression DoResolve (ResolveContext ec)
3553 child = child.Resolve (ec);
3557 eclass = child.eclass;
3562 public override void Emit (EmitContext ec)
3564 block.EmitScopeInitializers (ec);
3569 protected ParametersCompiled parameters;
3570 protected ParameterInfo[] parameter_info;
3571 protected bool resolved;
3572 protected ToplevelBlock top_block;
3573 protected StateMachine state_machine;
3574 protected Dictionary<string, object> labels;
3576 public ParametersBlock (Block parent, ParametersCompiled parameters, Location start, Flags flags = 0)
3577 : base (parent, 0, start, start)
3579 if (parameters == null)
3580 throw new ArgumentNullException ("parameters");
3582 this.parameters = parameters;
3583 ParametersBlock = this;
3585 this.flags |= flags | (parent.ParametersBlock.flags & (Flags.YieldBlock | Flags.AwaitBlock));
3587 this.top_block = parent.ParametersBlock.top_block;
3588 ProcessParameters ();
3591 protected ParametersBlock (ParametersCompiled parameters, Location start)
3592 : base (null, 0, start, start)
3594 if (parameters == null)
3595 throw new ArgumentNullException ("parameters");
3597 this.parameters = parameters;
3598 ParametersBlock = this;
3602 // It's supposed to be used by method body implementation of anonymous methods
3604 protected ParametersBlock (ParametersBlock source, ParametersCompiled parameters)
3605 : base (null, 0, source.StartLocation, source.EndLocation)
3607 this.parameters = parameters;
3608 this.statements = source.statements;
3609 this.scope_initializers = source.scope_initializers;
3611 this.resolved = true;
3612 this.reachable = source.reachable;
3613 this.am_storey = source.am_storey;
3614 this.state_machine = source.state_machine;
3615 this.flags = source.flags & Flags.ReachableEnd;
3617 ParametersBlock = this;
3620 // Overwrite original for comparison purposes when linking cross references
3621 // between anonymous methods
3623 Original = source.Original;
3628 public bool IsAsync {
3630 return (flags & Flags.HasAsyncModifier) != 0;
3633 flags = value ? flags | Flags.HasAsyncModifier : flags & ~Flags.HasAsyncModifier;
3638 // Block has been converted to expression tree
3640 public bool IsExpressionTree {
3642 return (flags & Flags.IsExpressionTree) != 0;
3647 // The parameters for the block.
3649 public ParametersCompiled Parameters {
3655 public StateMachine StateMachine {
3657 return state_machine;
3661 public ToplevelBlock TopBlock {
3670 public bool Resolved {
3672 return (flags & Flags.Resolved) != 0;
3676 public int TemporaryLocalsCount { get; set; }
3681 // Checks whether all `out' parameters have been assigned.
3683 public void CheckControlExit (FlowAnalysisContext fc)
3685 CheckControlExit (fc, fc.DefiniteAssignment);
3688 public virtual void CheckControlExit (FlowAnalysisContext fc, DefiniteAssignmentBitSet dat)
3690 if (parameter_info == null)
3693 foreach (var p in parameter_info) {
3694 if (p.VariableInfo == null)
3697 if (p.VariableInfo.IsAssigned (dat))
3700 fc.Report.Error (177, p.Location,
3701 "The out parameter `{0}' must be assigned to before control leaves the current method",
3706 protected override void CloneTo (CloneContext clonectx, Statement t)
3708 base.CloneTo (clonectx, t);
3710 var target = (ParametersBlock) t;
3713 // Clone label statements as well as they contain block reference
3717 if (pb.labels != null) {
3718 target.labels = new Dictionary<string, object> ();
3720 foreach (var entry in pb.labels) {
3721 var list = entry.Value as List<LabeledStatement>;
3724 var list_clone = new List<LabeledStatement> ();
3725 foreach (var lentry in list) {
3726 list_clone.Add (RemapLabeledStatement (lentry, lentry.Block, clonectx.RemapBlockCopy (lentry.Block)));
3729 target.labels.Add (entry.Key, list_clone);
3731 var labeled = (LabeledStatement) entry.Value;
3732 target.labels.Add (entry.Key, RemapLabeledStatement (labeled, labeled.Block, clonectx.RemapBlockCopy (labeled.Block)));
3739 if (pb.Parent == null)
3742 pb = pb.Parent.ParametersBlock;
3746 public override Expression CreateExpressionTree (ResolveContext ec)
3748 if (statements.Count == 1) {
3749 Expression expr = statements[0].CreateExpressionTree (ec);
3750 if (scope_initializers != null)
3751 expr = new BlockScopeExpression (expr, this);
3756 return base.CreateExpressionTree (ec);
3759 public override void Emit (EmitContext ec)
3761 if (state_machine != null && state_machine.OriginalSourceBlock != this) {
3762 DefineStoreyContainer (ec, state_machine);
3763 state_machine.EmitStoreyInstantiation (ec, this);
3769 public void EmitEmbedded (EmitContext ec)
3771 if (state_machine != null && state_machine.OriginalSourceBlock != this) {
3772 DefineStoreyContainer (ec, state_machine);
3773 state_machine.EmitStoreyInstantiation (ec, this);
3779 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
3781 var res = base.DoFlowAnalysis (fc);
3783 if (HasReachableClosingBrace)
3784 CheckControlExit (fc);
3789 public LabeledStatement GetLabel (string name, Block block)
3792 // Cloned parameters blocks can have their own cloned version of top-level labels
3794 if (labels == null) {
3796 return Parent.ParametersBlock.GetLabel (name, block);
3802 if (!labels.TryGetValue (name, out value)) {
3806 var label = value as LabeledStatement;
3808 if (label != null) {
3809 if (IsLabelVisible (label, b))
3813 List<LabeledStatement> list = (List<LabeledStatement>) value;
3814 for (int i = 0; i < list.Count; ++i) {
3816 if (IsLabelVisible (label, b))
3824 static bool IsLabelVisible (LabeledStatement label, Block b)
3827 if (label.Block == b)
3830 } while (b != null);
3835 public ParameterInfo GetParameterInfo (Parameter p)
3837 for (int i = 0; i < parameters.Count; ++i) {
3838 if (parameters[i] == p)
3839 return parameter_info[i];
3842 throw new ArgumentException ("Invalid parameter");
3845 public ParameterReference GetParameterReference (int index, Location loc)
3847 return new ParameterReference (parameter_info[index], loc);
3850 public Statement PerformClone ()
3852 CloneContext clonectx = new CloneContext ();
3853 return Clone (clonectx);
3856 protected void ProcessParameters ()
3858 if (parameters.Count == 0)
3861 parameter_info = new ParameterInfo[parameters.Count];
3862 for (int i = 0; i < parameter_info.Length; ++i) {
3863 var p = parameters.FixedParameters[i];
3867 // TODO: Should use Parameter only and more block there
3868 parameter_info[i] = new ParameterInfo (this, i);
3870 AddLocalName (p.Name, parameter_info[i]);
3874 static LabeledStatement RemapLabeledStatement (LabeledStatement stmt, Block src, Block dst)
3876 var src_stmts = src.Statements;
3877 for (int i = 0; i < src_stmts.Count; ++i) {
3878 if (src_stmts[i] == stmt)
3879 return (LabeledStatement) dst.Statements[i];
3882 throw new InternalErrorException ("Should never be reached");
3885 public override bool Resolve (BlockContext bc)
3887 // TODO: if ((flags & Flags.Resolved) != 0)
3894 if (bc.HasSet (ResolveContext.Options.ExpressionTreeConversion))
3895 flags |= Flags.IsExpressionTree;
3898 PrepareAssignmentAnalysis (bc);
3900 if (!base.Resolve (bc))
3903 } catch (Exception e) {
3904 if (e is CompletionResult || bc.Report.IsDisabled || e is FatalException || bc.Report.Printer is NullReportPrinter || bc.Module.Compiler.Settings.BreakOnInternalError)
3907 if (bc.CurrentBlock != null) {
3908 bc.Report.Error (584, bc.CurrentBlock.StartLocation, "Internal compiler error: {0}", e.Message);
3910 bc.Report.Error (587, "Internal compiler error: {0}", e.Message);
3915 // If an asynchronous body of F is either an expression classified as nothing, or a
3916 // statement block where no return statements have expressions, the inferred return type is Task
3919 var am = bc.CurrentAnonymousMethod as AnonymousMethodBody;
3920 if (am != null && am.ReturnTypeInference != null && !am.ReturnTypeInference.HasBounds (0)) {
3921 am.ReturnTypeInference = null;
3922 am.ReturnType = bc.Module.PredefinedTypes.Task.TypeSpec;
3930 void PrepareAssignmentAnalysis (BlockContext bc)
3932 for (int i = 0; i < parameters.Count; ++i) {
3933 var par = parameters.FixedParameters[i];
3935 if ((par.ModFlags & Parameter.Modifier.OUT) == 0)
3938 parameter_info [i].VariableInfo = VariableInfo.Create (bc, (Parameter) par);
3942 public ToplevelBlock ConvertToIterator (IMethodData method, TypeDefinition host, TypeSpec iterator_type, bool is_enumerable)
3944 var iterator = new Iterator (this, method, host, iterator_type, is_enumerable);
3945 var stateMachine = new IteratorStorey (iterator);
3947 state_machine = stateMachine;
3948 iterator.SetStateMachine (stateMachine);
3950 var tlb = new ToplevelBlock (host.Compiler, Parameters, Location.Null, Flags.CompilerGenerated);
3951 tlb.Original = this;
3952 tlb.state_machine = stateMachine;
3953 tlb.AddStatement (new Return (iterator, iterator.Location));
3957 public ParametersBlock ConvertToAsyncTask (IMemberContext context, TypeDefinition host, ParametersCompiled parameters, TypeSpec returnType, TypeSpec delegateType, Location loc)
3959 for (int i = 0; i < parameters.Count; i++) {
3960 Parameter p = parameters[i];
3961 Parameter.Modifier mod = p.ModFlags;
3962 if ((mod & Parameter.Modifier.RefOutMask) != 0) {
3963 host.Compiler.Report.Error (1988, p.Location,
3964 "Async methods cannot have ref or out parameters");
3968 if (p is ArglistParameter) {
3969 host.Compiler.Report.Error (4006, p.Location,
3970 "__arglist is not allowed in parameter list of async methods");
3974 if (parameters.Types[i].IsPointer) {
3975 host.Compiler.Report.Error (4005, p.Location,
3976 "Async methods cannot have unsafe parameters");
3982 host.Compiler.Report.Warning (1998, 1, loc,
3983 "Async block lacks `await' operator and will run synchronously");
3986 var block_type = host.Module.Compiler.BuiltinTypes.Void;
3987 var initializer = new AsyncInitializer (this, host, block_type);
3988 initializer.Type = block_type;
3989 initializer.DelegateType = delegateType;
3991 var stateMachine = new AsyncTaskStorey (this, context, initializer, returnType);
3993 state_machine = stateMachine;
3994 initializer.SetStateMachine (stateMachine);
3996 const Flags flags = Flags.CompilerGenerated;
3998 var b = this is ToplevelBlock ?
3999 new ToplevelBlock (host.Compiler, Parameters, Location.Null, flags) :
4000 new ParametersBlock (Parent, parameters, Location.Null, flags | Flags.HasAsyncModifier);
4003 b.state_machine = stateMachine;
4004 b.AddStatement (new AsyncInitializerStatement (initializer));
4012 public class ToplevelBlock : ParametersBlock
4014 LocalVariable this_variable;
4015 CompilerContext compiler;
4016 Dictionary<string, object> names;
4018 List<ExplicitBlock> this_references;
4020 public ToplevelBlock (CompilerContext ctx, Location loc)
4021 : this (ctx, ParametersCompiled.EmptyReadOnlyParameters, loc)
4025 public ToplevelBlock (CompilerContext ctx, ParametersCompiled parameters, Location start, Flags flags = 0)
4026 : base (parameters, start)
4028 this.compiler = ctx;
4032 ProcessParameters ();
4036 // Recreates a top level block from parameters block. Used for
4037 // compiler generated methods where the original block comes from
4038 // explicit child block. This works for already resolved blocks
4039 // only to ensure we resolve them in the correct flow order
4041 public ToplevelBlock (ParametersBlock source, ParametersCompiled parameters)
4042 : base (source, parameters)
4044 this.compiler = source.TopBlock.compiler;
4048 public bool IsIterator {
4050 return (flags & Flags.Iterator) != 0;
4053 flags = value ? flags | Flags.Iterator : flags & ~Flags.Iterator;
4057 public Report Report {
4059 return compiler.Report;
4064 // Used by anonymous blocks to track references of `this' variable
4066 public List<ExplicitBlock> ThisReferencesFromChildrenBlock {
4068 return this_references;
4073 // Returns the "this" instance variable of this block.
4074 // See AddThisVariable() for more information.
4076 public LocalVariable ThisVariable {
4078 return this_variable;
4082 public void AddLocalName (string name, INamedBlockVariable li, bool ignoreChildrenBlocks)
4085 names = new Dictionary<string, object> ();
4088 if (!names.TryGetValue (name, out value)) {
4089 names.Add (name, li);
4093 INamedBlockVariable existing = value as INamedBlockVariable;
4094 List<INamedBlockVariable> existing_list;
4095 if (existing != null) {
4096 existing_list = new List<INamedBlockVariable> ();
4097 existing_list.Add (existing);
4098 names[name] = existing_list;
4100 existing_list = (List<INamedBlockVariable>) value;
4104 // A collision checking between local names
4106 var variable_block = li.Block.Explicit;
4107 for (int i = 0; i < existing_list.Count; ++i) {
4108 existing = existing_list[i];
4109 Block b = existing.Block.Explicit;
4111 // Collision at same level
4112 if (variable_block == b) {
4113 li.Block.Error_AlreadyDeclared (name, li);
4117 // Collision with parent
4118 Block parent = variable_block;
4119 while ((parent = parent.Parent) != null) {
4121 li.Block.Error_AlreadyDeclared (name, li, "parent or current");
4122 i = existing_list.Count;
4127 if (!ignoreChildrenBlocks && variable_block.Parent != b.Parent) {
4128 // Collision with children
4129 while ((b = b.Parent) != null) {
4130 if (variable_block == b) {
4131 li.Block.Error_AlreadyDeclared (name, li, "child");
4132 i = existing_list.Count;
4139 existing_list.Add (li);
4142 public void AddLabel (string name, LabeledStatement label)
4145 labels = new Dictionary<string, object> ();
4148 if (!labels.TryGetValue (name, out value)) {
4149 labels.Add (name, label);
4153 LabeledStatement existing = value as LabeledStatement;
4154 List<LabeledStatement> existing_list;
4155 if (existing != null) {
4156 existing_list = new List<LabeledStatement> ();
4157 existing_list.Add (existing);
4158 labels[name] = existing_list;
4160 existing_list = (List<LabeledStatement>) value;
4164 // A collision checking between labels
4166 for (int i = 0; i < existing_list.Count; ++i) {
4167 existing = existing_list[i];
4168 Block b = existing.Block;
4170 // Collision at same level
4171 if (label.Block == b) {
4172 Report.SymbolRelatedToPreviousError (existing.loc, name);
4173 Report.Error (140, label.loc, "The label `{0}' is a duplicate", name);
4177 // Collision with parent
4179 while ((b = b.Parent) != null) {
4180 if (existing.Block == b) {
4181 Report.Error (158, label.loc,
4182 "The label `{0}' shadows another label by the same name in a contained scope", name);
4183 i = existing_list.Count;
4188 // Collision with with children
4190 while ((b = b.Parent) != null) {
4191 if (label.Block == b) {
4192 Report.Error (158, label.loc,
4193 "The label `{0}' shadows another label by the same name in a contained scope", name);
4194 i = existing_list.Count;
4200 existing_list.Add (label);
4203 public void AddThisReferenceFromChildrenBlock (ExplicitBlock block)
4205 if (this_references == null)
4206 this_references = new List<ExplicitBlock> ();
4208 if (!this_references.Contains (block))
4209 this_references.Add (block);
4212 public void RemoveThisReferenceFromChildrenBlock (ExplicitBlock block)
4214 this_references.Remove (block);
4218 // Creates an arguments set from all parameters, useful for method proxy calls
4220 public Arguments GetAllParametersArguments ()
4222 int count = parameters.Count;
4223 Arguments args = new Arguments (count);
4224 for (int i = 0; i < count; ++i) {
4225 var pi = parameter_info[i];
4226 var arg_expr = GetParameterReference (i, pi.Location);
4228 Argument.AType atype_modifier;
4229 switch (pi.Parameter.ParameterModifier & Parameter.Modifier.RefOutMask) {
4230 case Parameter.Modifier.REF:
4231 atype_modifier = Argument.AType.Ref;
4233 case Parameter.Modifier.OUT:
4234 atype_modifier = Argument.AType.Out;
4241 args.Add (new Argument (arg_expr, atype_modifier));
4248 // Lookup inside a block, the returned value can represent 3 states
4250 // true+variable: A local name was found and it's valid
4251 // false+variable: A local name was found in a child block only
4252 // false+null: No local name was found
4254 public bool GetLocalName (string name, Block block, ref INamedBlockVariable variable)
4260 if (!names.TryGetValue (name, out value))
4263 variable = value as INamedBlockVariable;
4265 if (variable != null) {
4267 if (variable.Block == b.Original)
4271 } while (b != null);
4279 } while (b != null);
4281 List<INamedBlockVariable> list = (List<INamedBlockVariable>) value;
4282 for (int i = 0; i < list.Count; ++i) {
4285 if (variable.Block == b.Original)
4289 } while (b != null);
4297 } while (b != null);
4307 public void IncludeBlock (ParametersBlock pb, ToplevelBlock block)
4309 if (block.names != null) {
4310 foreach (var n in block.names) {
4311 var variable = n.Value as INamedBlockVariable;
4312 if (variable != null) {
4313 if (variable.Block.ParametersBlock == pb)
4314 AddLocalName (n.Key, variable, false);
4318 foreach (var v in (List<INamedBlockVariable>) n.Value)
4319 if (v.Block.ParametersBlock == pb)
4320 AddLocalName (n.Key, v, false);
4326 // This is used by non-static `struct' constructors which do not have an
4327 // initializer - in this case, the constructor must initialize all of the
4328 // struct's fields. To do this, we add a "this" variable and use the flow
4329 // analysis code to ensure that it's been fully initialized before control
4330 // leaves the constructor.
4332 public void AddThisVariable (BlockContext bc)
4334 if (this_variable != null)
4335 throw new InternalErrorException (StartLocation.ToString ());
4337 this_variable = new LocalVariable (this, "this", LocalVariable.Flags.IsThis | LocalVariable.Flags.Used, StartLocation);
4338 this_variable.Type = bc.CurrentType;
4339 this_variable.PrepareAssignmentAnalysis (bc);
4342 public override void CheckControlExit (FlowAnalysisContext fc, DefiniteAssignmentBitSet dat)
4345 // If we're a non-static struct constructor which doesn't have an
4346 // initializer, then we must initialize all of the struct's fields.
4348 if (this_variable != null)
4349 this_variable.IsThisAssigned (fc, this);
4351 base.CheckControlExit (fc, dat);
4354 public override void Emit (EmitContext ec)
4356 if (Report.Errors > 0)
4360 if (IsCompilerGenerated) {
4361 using (ec.With (BuilderContext.Options.OmitDebugInfo, true)) {
4369 // If `HasReturnLabel' is set, then we already emitted a
4370 // jump to the end of the method, so we must emit a `ret'
4373 // Unfortunately, System.Reflection.Emit automatically emits
4374 // a leave to the end of a finally block. This is a problem
4375 // if no code is following the try/finally block since we may
4376 // jump to a point after the end of the method.
4377 // As a workaround, we're always creating a return label in
4380 if (ec.HasReturnLabel || HasReachableClosingBrace) {
4381 if (ec.HasReturnLabel)
4382 ec.MarkLabel (ec.ReturnLabel);
4384 if (ec.EmitAccurateDebugInfo && !IsCompilerGenerated)
4385 ec.Mark (EndLocation);
4387 if (ec.ReturnType.Kind != MemberKind.Void)
4388 ec.Emit (OpCodes.Ldloc, ec.TemporaryReturn ());
4390 ec.Emit (OpCodes.Ret);
4393 } catch (Exception e) {
4394 throw new InternalErrorException (e, StartLocation);
4398 public bool Resolve (BlockContext bc, IMethodData md)
4403 var errors = bc.Report.Errors;
4407 if (bc.Report.Errors > errors)
4410 MarkReachable (new Reachability ());
4412 if (HasReachableClosingBrace && bc.ReturnType.Kind != MemberKind.Void) {
4413 // TODO: var md = bc.CurrentMemberDefinition;
4414 bc.Report.Error (161, md.Location, "`{0}': not all code paths return a value", md.GetSignatureForError ());
4417 if ((flags & Flags.NoFlowAnalysis) != 0)
4420 var fc = new FlowAnalysisContext (bc.Module.Compiler, this, bc.AssignmentInfoOffset);
4423 } catch (Exception e) {
4424 throw new InternalErrorException (e, StartLocation);
4431 public class SwitchLabel : Statement
4439 // if expr == null, then it is the default case.
4441 public SwitchLabel (Expression expr, Location l)
4447 public bool IsDefault {
4449 return label == null;
4453 public Expression Label {
4459 public Location Location {
4465 public Constant Converted {
4474 public bool SectionStart { get; set; }
4476 public Label GetILLabel (EmitContext ec)
4478 if (il_label == null){
4479 il_label = ec.DefineLabel ();
4482 return il_label.Value;
4485 protected override void DoEmit (EmitContext ec)
4487 ec.MarkLabel (GetILLabel (ec));
4490 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
4495 fc.DefiniteAssignment = new DefiniteAssignmentBitSet (fc.SwitchInitialDefinitiveAssignment);
4499 public override bool Resolve (BlockContext bc)
4501 if (ResolveAndReduce (bc))
4502 bc.Switch.RegisterLabel (bc, this);
4508 // Resolves the expression, reduces it to a literal if possible
4509 // and then converts it to the requested type.
4511 bool ResolveAndReduce (BlockContext rc)
4516 var c = label.ResolveLabelConstant (rc);
4520 if (rc.Switch.IsNullable && c is NullLiteral) {
4525 converted = c.ImplicitConversionRequired (rc, rc.Switch.SwitchType);
4526 return converted != null;
4529 public void Error_AlreadyOccurs (ResolveContext ec, SwitchLabel collision_with)
4531 ec.Report.SymbolRelatedToPreviousError (collision_with.loc, null);
4532 ec.Report.Error (152, loc, "The label `{0}' already occurs in this switch statement", GetSignatureForError ());
4535 protected override void CloneTo (CloneContext clonectx, Statement target)
4537 var t = (SwitchLabel) target;
4539 t.label = label.Clone (clonectx);
4542 public override object Accept (StructuralVisitor visitor)
4544 return visitor.Visit (this);
4547 public string GetSignatureForError ()
4550 if (converted == null)
4553 label = converted.GetValueAsLiteral ();
4555 return string.Format ("case {0}:", label);
4559 public class Switch : LoopStatement
4561 // structure used to hold blocks of keys while calculating table switch
4562 sealed class LabelsRange : IComparable<LabelsRange>
4564 public readonly long min;
4566 public readonly List<long> label_values;
4568 public LabelsRange (long value)
4571 label_values = new List<long> ();
4572 label_values.Add (value);
4575 public LabelsRange (long min, long max, ICollection<long> values)
4579 this.label_values = new List<long> (values);
4584 return max - min + 1;
4588 public bool AddValue (long value)
4590 var gap = value - min + 1;
4591 // Ensure the range has > 50% occupancy
4592 if (gap > 2 * (label_values.Count + 1) || gap <= 0)
4596 label_values.Add (value);
4600 public int CompareTo (LabelsRange other)
4602 int nLength = label_values.Count;
4603 int nLengthOther = other.label_values.Count;
4604 if (nLengthOther == nLength)
4605 return (int) (other.min - min);
4607 return nLength - nLengthOther;
4611 sealed class DispatchStatement : Statement
4613 readonly Switch body;
4615 public DispatchStatement (Switch body)
4620 protected override void CloneTo (CloneContext clonectx, Statement target)
4622 throw new NotImplementedException ();
4625 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
4630 protected override void DoEmit (EmitContext ec)
4632 body.EmitDispatch (ec);
4636 class MissingBreak : Statement
4638 readonly SwitchLabel label;
4640 public MissingBreak (SwitchLabel sl)
4646 public bool FallOut { get; set; }
4648 protected override void DoEmit (EmitContext ec)
4652 protected override void CloneTo (CloneContext clonectx, Statement target)
4656 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
4659 fc.Report.Error (8070, loc, "Control cannot fall out of switch statement through final case label `{0}'",
4660 label.GetSignatureForError ());
4662 fc.Report.Error (163, loc, "Control cannot fall through from one case label `{0}' to another",
4663 label.GetSignatureForError ());
4669 public Expression Expr;
4672 // Mapping of all labels to their SwitchLabels
4674 Dictionary<long, SwitchLabel> labels;
4675 Dictionary<string, SwitchLabel> string_labels;
4676 List<SwitchLabel> case_labels;
4678 List<Tuple<GotoCase, Constant>> goto_cases;
4679 List<DefiniteAssignmentBitSet> end_reachable_das;
4682 /// The governing switch type
4684 public TypeSpec SwitchType;
4686 Expression new_expr;
4688 SwitchLabel case_null;
4689 SwitchLabel case_default;
4691 Label defaultLabel, nullLabel;
4692 VariableReference value;
4693 ExpressionStatement string_dictionary;
4694 FieldExpr switch_cache_field;
4695 ExplicitBlock block;
4699 // Nullable Types support
4701 Nullable.Unwrap unwrap;
4703 public Switch (Expression e, ExplicitBlock block, Location l)
4711 public SwitchLabel ActiveLabel { get; set; }
4713 public ExplicitBlock Block {
4719 public SwitchLabel DefaultLabel {
4721 return case_default;
4725 public bool IsNullable {
4727 return unwrap != null;
4731 public List<SwitchLabel> RegisteredLabels {
4738 // Determines the governing type for a switch. The returned
4739 // expression might be the expression from the switch, or an
4740 // expression that includes any potential conversions to
4742 static Expression SwitchGoverningType (ResolveContext rc, Expression expr, bool unwrapExpr)
4744 switch (expr.Type.BuiltinType) {
4745 case BuiltinTypeSpec.Type.Byte:
4746 case BuiltinTypeSpec.Type.SByte:
4747 case BuiltinTypeSpec.Type.UShort:
4748 case BuiltinTypeSpec.Type.Short:
4749 case BuiltinTypeSpec.Type.UInt:
4750 case BuiltinTypeSpec.Type.Int:
4751 case BuiltinTypeSpec.Type.ULong:
4752 case BuiltinTypeSpec.Type.Long:
4753 case BuiltinTypeSpec.Type.Char:
4754 case BuiltinTypeSpec.Type.String:
4755 case BuiltinTypeSpec.Type.Bool:
4759 if (expr.Type.IsEnum)
4763 // Try to find a *user* defined implicit conversion.
4765 // If there is no implicit conversion, or if there are multiple
4766 // conversions, we have to report an error
4768 Expression converted = null;
4769 foreach (TypeSpec tt in rc.Module.PredefinedTypes.SwitchUserTypes) {
4771 if (!unwrapExpr && tt.IsNullableType && expr.Type.IsNullableType)
4774 var restr = Convert.UserConversionRestriction.ImplicitOnly |
4775 Convert.UserConversionRestriction.ProbingOnly;
4778 restr |= Convert.UserConversionRestriction.NullableSourceOnly;
4780 var e = Convert.UserDefinedConversion (rc, expr, tt, restr, Location.Null);
4785 // Ignore over-worked ImplicitUserConversions that do
4786 // an implicit conversion in addition to the user conversion.
4788 var uc = e as UserCast;
4792 if (converted != null){
4793 // rc.Report.ExtraInformation (loc, "(Ambiguous implicit user defined conversion in previous ");
4802 public static TypeSpec[] CreateSwitchUserTypes (ModuleContainer module, TypeSpec nullable)
4804 var types = module.Compiler.BuiltinTypes;
4806 // LAMESPEC: For some reason it does not contain bool which looks like csc bug
4807 TypeSpec[] stypes = new[] {
4820 if (nullable != null) {
4822 Array.Resize (ref stypes, stypes.Length + 9);
4824 for (int i = 0; i < 9; ++i) {
4825 stypes [10 + i] = nullable.MakeGenericType (module, new [] { stypes [i] });
4832 public void RegisterLabel (BlockContext rc, SwitchLabel sl)
4834 case_labels.Add (sl);
4837 if (case_default != null) {
4838 sl.Error_AlreadyOccurs (rc, case_default);
4847 if (string_labels != null) {
4848 string string_value = sl.Converted.GetValue () as string;
4849 if (string_value == null)
4852 string_labels.Add (string_value, sl);
4854 if (sl.Converted is NullLiteral) {
4857 labels.Add (sl.Converted.GetValueAsLong (), sl);
4860 } catch (ArgumentException) {
4861 if (string_labels != null)
4862 sl.Error_AlreadyOccurs (rc, string_labels[(string) sl.Converted.GetValue ()]);
4864 sl.Error_AlreadyOccurs (rc, labels[sl.Converted.GetValueAsLong ()]);
4869 // This method emits code for a lookup-based switch statement (non-string)
4870 // Basically it groups the cases into blocks that are at least half full,
4871 // and then spits out individual lookup opcodes for each block.
4872 // It emits the longest blocks first, and short blocks are just
4873 // handled with direct compares.
4875 void EmitTableSwitch (EmitContext ec, Expression val)
4877 if (labels != null && labels.Count > 0) {
4878 List<LabelsRange> ranges;
4879 if (string_labels != null) {
4880 // We have done all hard work for string already
4881 // setup single range only
4882 ranges = new List<LabelsRange> (1);
4883 ranges.Add (new LabelsRange (0, labels.Count - 1, labels.Keys));
4885 var element_keys = new long[labels.Count];
4886 labels.Keys.CopyTo (element_keys, 0);
4887 Array.Sort (element_keys);
4890 // Build possible ranges of switch labes to reduce number
4893 ranges = new List<LabelsRange> (element_keys.Length);
4894 var range = new LabelsRange (element_keys[0]);
4896 for (int i = 1; i < element_keys.Length; ++i) {
4897 var l = element_keys[i];
4898 if (range.AddValue (l))
4901 range = new LabelsRange (l);
4905 // sort the blocks so we can tackle the largest ones first
4909 Label lbl_default = defaultLabel;
4910 TypeSpec compare_type = SwitchType.IsEnum ? EnumSpec.GetUnderlyingType (SwitchType) : SwitchType;
4912 for (int range_index = ranges.Count - 1; range_index >= 0; --range_index) {
4913 LabelsRange kb = ranges[range_index];
4914 lbl_default = (range_index == 0) ? defaultLabel : ec.DefineLabel ();
4916 // Optimize small ranges using simple equality check
4917 if (kb.Range <= 2) {
4918 foreach (var key in kb.label_values) {
4919 SwitchLabel sl = labels[key];
4920 if (sl == case_default || sl == case_null)
4923 if (sl.Converted.IsZeroInteger) {
4924 val.EmitBranchable (ec, sl.GetILLabel (ec), false);
4927 sl.Converted.Emit (ec);
4928 ec.Emit (OpCodes.Beq, sl.GetILLabel (ec));
4932 // TODO: if all the keys in the block are the same and there are
4933 // no gaps/defaults then just use a range-check.
4934 if (compare_type.BuiltinType == BuiltinTypeSpec.Type.Long || compare_type.BuiltinType == BuiltinTypeSpec.Type.ULong) {
4935 // TODO: optimize constant/I4 cases
4937 // check block range (could be > 2^31)
4939 ec.EmitLong (kb.min);
4940 ec.Emit (OpCodes.Blt, lbl_default);
4943 ec.EmitLong (kb.max);
4944 ec.Emit (OpCodes.Bgt, lbl_default);
4949 ec.EmitLong (kb.min);
4950 ec.Emit (OpCodes.Sub);
4953 ec.Emit (OpCodes.Conv_I4); // assumes < 2^31 labels!
4957 int first = (int) kb.min;
4960 ec.Emit (OpCodes.Sub);
4961 } else if (first < 0) {
4962 ec.EmitInt (-first);
4963 ec.Emit (OpCodes.Add);
4967 // first, build the list of labels for the switch
4969 long cJumps = kb.Range;
4970 Label[] switch_labels = new Label[cJumps];
4971 for (int iJump = 0; iJump < cJumps; iJump++) {
4972 var key = kb.label_values[iKey];
4973 if (key == kb.min + iJump) {
4974 switch_labels[iJump] = labels[key].GetILLabel (ec);
4977 switch_labels[iJump] = lbl_default;
4981 // emit the switch opcode
4982 ec.Emit (OpCodes.Switch, switch_labels);
4985 // mark the default for this block
4986 if (range_index != 0)
4987 ec.MarkLabel (lbl_default);
4990 // the last default just goes to the end
4991 if (ranges.Count > 0)
4992 ec.Emit (OpCodes.Br, lbl_default);
4996 public SwitchLabel FindLabel (Constant value)
4998 SwitchLabel sl = null;
5000 if (string_labels != null) {
5001 string s = value.GetValue () as string;
5003 if (case_null != null)
5005 else if (case_default != null)
5008 string_labels.TryGetValue (s, out sl);
5011 if (value is NullLiteral) {
5014 labels.TryGetValue (value.GetValueAsLong (), out sl);
5021 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
5023 Expr.FlowAnalysis (fc);
5025 var prev_switch = fc.SwitchInitialDefinitiveAssignment;
5026 var InitialDefinitiveAssignment = fc.DefiniteAssignment;
5027 fc.SwitchInitialDefinitiveAssignment = InitialDefinitiveAssignment;
5029 block.FlowAnalysis (fc);
5031 fc.SwitchInitialDefinitiveAssignment = prev_switch;
5033 if (end_reachable_das != null) {
5034 var sections_das = DefiniteAssignmentBitSet.And (end_reachable_das);
5035 InitialDefinitiveAssignment |= sections_das;
5036 end_reachable_das = null;
5039 fc.DefiniteAssignment = InitialDefinitiveAssignment;
5041 return case_default != null && !end_reachable;
5044 public override bool Resolve (BlockContext ec)
5046 Expr = Expr.Resolve (ec);
5051 // LAMESPEC: User conversion from non-nullable governing type has a priority
5053 new_expr = SwitchGoverningType (ec, Expr, false);
5055 if (new_expr == null) {
5056 if (Expr.Type.IsNullableType) {
5057 unwrap = Nullable.Unwrap.Create (Expr, false);
5062 // Unwrap + user conversion using non-nullable type is not allowed but user operator
5063 // involving nullable Expr and nullable governing type is
5065 new_expr = SwitchGoverningType (ec, unwrap, true);
5069 if (new_expr == null) {
5070 if (Expr.Type != InternalType.ErrorType) {
5071 ec.Report.Error (151, loc,
5072 "A switch expression of type `{0}' cannot be converted to an integral type, bool, char, string, enum or nullable type",
5073 Expr.Type.GetSignatureForError ());
5079 SwitchType = new_expr.Type;
5080 if (SwitchType.IsNullableType) {
5081 new_expr = unwrap = Nullable.Unwrap.Create (new_expr, true);
5082 SwitchType = Nullable.NullableInfo.GetUnderlyingType (SwitchType);
5085 if (SwitchType.BuiltinType == BuiltinTypeSpec.Type.Bool && ec.Module.Compiler.Settings.Version == LanguageVersion.ISO_1) {
5086 ec.Report.FeatureIsNotAvailable (ec.Module.Compiler, loc, "switch expression of boolean type");
5090 if (block.Statements.Count == 0)
5093 if (SwitchType.BuiltinType == BuiltinTypeSpec.Type.String) {
5094 string_labels = new Dictionary<string, SwitchLabel> ();
5096 labels = new Dictionary<long, SwitchLabel> ();
5099 case_labels = new List<SwitchLabel> ();
5101 var constant = new_expr as Constant;
5104 // Don't need extra variable for constant switch or switch with
5105 // only default case
5107 if (constant == null) {
5109 // Store switch expression for comparison purposes
5111 value = new_expr as VariableReference;
5112 if (value == null && !HasOnlyDefaultSection ()) {
5113 var current_block = ec.CurrentBlock;
5114 ec.CurrentBlock = Block;
5115 // Create temporary variable inside switch scope
5116 value = TemporaryVariableReference.Create (SwitchType, ec.CurrentBlock, loc);
5118 ec.CurrentBlock = current_block;
5122 Switch old_switch = ec.Switch;
5124 var parent_los = ec.EnclosingLoopOrSwitch;
5125 ec.EnclosingLoopOrSwitch = this;
5127 var ok = Statement.Resolve (ec);
5129 ec.EnclosingLoopOrSwitch = parent_los;
5130 ec.Switch = old_switch;
5133 // Check if all goto cases are valid. Needs to be done after switch
5134 // is resolved because goto can jump forward in the scope.
5136 if (goto_cases != null) {
5137 foreach (var gc in goto_cases) {
5138 if (gc.Item1 == null) {
5139 if (DefaultLabel == null) {
5140 Goto.Error_UnknownLabel (ec, "default", loc);
5146 var sl = FindLabel (gc.Item2);
5148 Goto.Error_UnknownLabel (ec, "case " + gc.Item2.GetValueAsLiteral (), loc);
5150 gc.Item1.Label = sl;
5158 if (constant == null && SwitchType.BuiltinType == BuiltinTypeSpec.Type.String && string_labels.Count > 6) {
5159 ResolveStringSwitchMap (ec);
5163 // Anonymous storey initialization has to happen before
5164 // any generated switch dispatch
5166 block.InsertStatement (0, new DispatchStatement (this));
5171 bool HasOnlyDefaultSection ()
5173 for (int i = 0; i < block.Statements.Count; ++i) {
5174 var s = block.Statements[i] as SwitchLabel;
5176 if (s == null || s.IsDefault)
5185 public override Reachability MarkReachable (Reachability rc)
5187 if (rc.IsUnreachable)
5190 base.MarkReachable (rc);
5192 block.MarkReachableScope (rc);
5194 if (block.Statements.Count == 0)
5197 SwitchLabel constant_label = null;
5198 var constant = new_expr as Constant;
5200 if (constant != null) {
5201 constant_label = FindLabel (constant) ?? case_default;
5202 if (constant_label == null) {
5203 block.Statements.RemoveAt (0);
5208 var section_rc = new Reachability ();
5209 SwitchLabel prev_label = null;
5211 for (int i = 0; i < block.Statements.Count; ++i) {
5212 var s = block.Statements[i];
5213 var sl = s as SwitchLabel;
5215 if (sl != null && sl.SectionStart) {
5217 // Section is marked already via goto case
5219 if (!sl.IsUnreachable) {
5220 section_rc = new Reachability ();
5224 if (constant_label != null && constant_label != sl)
5225 section_rc = Reachability.CreateUnreachable ();
5226 else if (section_rc.IsUnreachable) {
5227 section_rc = new Reachability ();
5229 if (prev_label != null) {
5230 sl.SectionStart = false;
5231 s = new MissingBreak (prev_label);
5232 s.MarkReachable (rc);
5233 block.Statements.Insert (i - 1, s);
5241 section_rc = s.MarkReachable (section_rc);
5244 if (!section_rc.IsUnreachable && prev_label != null) {
5245 prev_label.SectionStart = false;
5246 var s = new MissingBreak (prev_label) {
5250 s.MarkReachable (rc);
5251 block.Statements.Add (s);
5255 // Reachability can affect parent only when all possible paths are handled but
5256 // we still need to run reachability check on switch body to check for fall-through
5258 if (case_default == null && constant_label == null)
5262 // We have at least one local exit from the switch
5267 return Reachability.CreateUnreachable ();
5270 public void RegisterGotoCase (GotoCase gotoCase, Constant value)
5272 if (goto_cases == null)
5273 goto_cases = new List<Tuple<GotoCase, Constant>> ();
5275 goto_cases.Add (Tuple.Create (gotoCase, value));
5279 // Converts string switch into string hashtable
5281 void ResolveStringSwitchMap (ResolveContext ec)
5283 FullNamedExpression string_dictionary_type;
5284 if (ec.Module.PredefinedTypes.Dictionary.Define ()) {
5285 string_dictionary_type = new TypeExpression (
5286 ec.Module.PredefinedTypes.Dictionary.TypeSpec.MakeGenericType (ec,
5287 new [] { ec.BuiltinTypes.String, ec.BuiltinTypes.Int }),
5289 } else if (ec.Module.PredefinedTypes.Hashtable.Define ()) {
5290 string_dictionary_type = new TypeExpression (ec.Module.PredefinedTypes.Hashtable.TypeSpec, loc);
5292 ec.Module.PredefinedTypes.Dictionary.Resolve ();
5296 var ctype = ec.CurrentMemberDefinition.Parent.PartialContainer;
5297 Field field = new Field (ctype, string_dictionary_type,
5298 Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
5299 new MemberName (CompilerGeneratedContainer.MakeName (null, "f", "switch$map", ec.Module.CounterSwitchTypes++), loc), null);
5300 if (!field.Define ())
5302 ctype.AddField (field);
5304 var init = new List<Expression> ();
5306 labels = new Dictionary<long, SwitchLabel> (string_labels.Count);
5307 string value = null;
5309 foreach (SwitchLabel sl in case_labels) {
5311 if (sl.SectionStart)
5312 labels.Add (++counter, sl);
5314 if (sl == case_default || sl == case_null)
5317 value = (string) sl.Converted.GetValue ();
5318 var init_args = new List<Expression> (2);
5319 init_args.Add (new StringLiteral (ec.BuiltinTypes, value, sl.Location));
5321 sl.Converted = new IntConstant (ec.BuiltinTypes, counter, loc);
5322 init_args.Add (sl.Converted);
5324 init.Add (new CollectionElementInitializer (init_args, loc));
5327 Arguments args = new Arguments (1);
5328 args.Add (new Argument (new IntConstant (ec.BuiltinTypes, init.Count, loc)));
5329 Expression initializer = new NewInitialize (string_dictionary_type, args,
5330 new CollectionOrObjectInitializers (init, loc), loc);
5332 switch_cache_field = new FieldExpr (field, loc);
5333 string_dictionary = new SimpleAssign (switch_cache_field, initializer.Resolve (ec));
5336 void DoEmitStringSwitch (EmitContext ec)
5338 Label l_initialized = ec.DefineLabel ();
5341 // Skip initialization when value is null
5343 value.EmitBranchable (ec, nullLabel, false);
5346 // Check if string dictionary is initialized and initialize
5348 switch_cache_field.EmitBranchable (ec, l_initialized, true);
5349 using (ec.With (BuilderContext.Options.OmitDebugInfo, true)) {
5350 string_dictionary.EmitStatement (ec);
5352 ec.MarkLabel (l_initialized);
5354 LocalTemporary string_switch_variable = new LocalTemporary (ec.BuiltinTypes.Int);
5356 ResolveContext rc = new ResolveContext (ec.MemberContext);
5358 if (switch_cache_field.Type.IsGeneric) {
5359 Arguments get_value_args = new Arguments (2);
5360 get_value_args.Add (new Argument (value));
5361 get_value_args.Add (new Argument (string_switch_variable, Argument.AType.Out));
5362 Expression get_item = new Invocation (new MemberAccess (switch_cache_field, "TryGetValue", loc), get_value_args).Resolve (rc);
5363 if (get_item == null)
5367 // A value was not found, go to default case
5369 get_item.EmitBranchable (ec, defaultLabel, false);
5371 Arguments get_value_args = new Arguments (1);
5372 get_value_args.Add (new Argument (value));
5374 Expression get_item = new ElementAccess (switch_cache_field, get_value_args, loc).Resolve (rc);
5375 if (get_item == null)
5378 LocalTemporary get_item_object = new LocalTemporary (ec.BuiltinTypes.Object);
5379 get_item_object.EmitAssign (ec, get_item, true, false);
5380 ec.Emit (OpCodes.Brfalse, defaultLabel);
5382 ExpressionStatement get_item_int = (ExpressionStatement) new SimpleAssign (string_switch_variable,
5383 new Cast (new TypeExpression (ec.BuiltinTypes.Int, loc), get_item_object, loc)).Resolve (rc);
5385 get_item_int.EmitStatement (ec);
5386 get_item_object.Release (ec);
5389 EmitTableSwitch (ec, string_switch_variable);
5390 string_switch_variable.Release (ec);
5394 // Emits switch using simple if/else comparison for small label count (4 + optional default)
5396 void EmitShortSwitch (EmitContext ec)
5398 MethodSpec equal_method = null;
5399 if (SwitchType.BuiltinType == BuiltinTypeSpec.Type.String) {
5400 equal_method = ec.Module.PredefinedMembers.StringEqual.Resolve (loc);
5403 if (equal_method != null) {
5404 value.EmitBranchable (ec, nullLabel, false);
5407 for (int i = 0; i < case_labels.Count; ++i) {
5408 var label = case_labels [i];
5409 if (label == case_default || label == case_null)
5412 var constant = label.Converted;
5414 if (equal_method != null) {
5418 var call = new CallEmitter ();
5419 call.EmitPredefined (ec, equal_method, new Arguments (0));
5420 ec.Emit (OpCodes.Brtrue, label.GetILLabel (ec));
5424 if (constant.IsZeroInteger && constant.Type.BuiltinType != BuiltinTypeSpec.Type.Long && constant.Type.BuiltinType != BuiltinTypeSpec.Type.ULong) {
5425 value.EmitBranchable (ec, label.GetILLabel (ec), false);
5431 ec.Emit (OpCodes.Beq, label.GetILLabel (ec));
5434 ec.Emit (OpCodes.Br, defaultLabel);
5437 void EmitDispatch (EmitContext ec)
5439 if (value == null) {
5441 // Constant switch, we've already done the work if there is only 1 label
5445 foreach (var sl in case_labels) {
5446 if (sl.IsUnreachable)
5449 if (reachable++ > 0) {
5450 var constant = (Constant) new_expr;
5451 var constant_label = FindLabel (constant) ?? case_default;
5453 ec.Emit (OpCodes.Br, constant_label.GetILLabel (ec));
5461 if (string_dictionary != null) {
5462 DoEmitStringSwitch (ec);
5463 } else if (case_labels.Count < 4 || string_labels != null) {
5464 EmitShortSwitch (ec);
5466 EmitTableSwitch (ec, value);
5470 protected override void DoEmit (EmitContext ec)
5473 // Setup the codegen context
5475 Label old_end = ec.LoopEnd;
5476 Switch old_switch = ec.Switch;
5478 ec.LoopEnd = ec.DefineLabel ();
5481 defaultLabel = case_default == null ? ec.LoopEnd : case_default.GetILLabel (ec);
5482 nullLabel = case_null == null ? defaultLabel : case_null.GetILLabel (ec);
5484 if (value != null) {
5487 unwrap.EmitCheck (ec);
5488 ec.Emit (OpCodes.Brfalse, nullLabel);
5489 value.EmitAssign (ec, new_expr, false, false);
5490 } else if (new_expr != value) {
5491 value.EmitAssign (ec, new_expr, false, false);
5496 // Next statement is compiler generated we don't need extra
5497 // nop when we can use the statement for sequence point
5499 ec.Mark (block.StartLocation);
5500 block.IsCompilerGenerated = true;
5502 new_expr.EmitSideEffect (ec);
5507 // Restore context state.
5508 ec.MarkLabel (ec.LoopEnd);
5511 // Restore the previous context
5513 ec.LoopEnd = old_end;
5514 ec.Switch = old_switch;
5517 protected override void CloneTo (CloneContext clonectx, Statement t)
5519 Switch target = (Switch) t;
5521 target.Expr = Expr.Clone (clonectx);
5522 target.Statement = target.block = (ExplicitBlock) block.Clone (clonectx);
5525 public override object Accept (StructuralVisitor visitor)
5527 return visitor.Visit (this);
5530 public override void AddEndDefiniteAssignment (FlowAnalysisContext fc)
5532 if (case_default == null && !(new_expr is Constant))
5535 if (end_reachable_das == null)
5536 end_reachable_das = new List<DefiniteAssignmentBitSet> ();
5538 end_reachable_das.Add (fc.DefiniteAssignment);
5541 public override void SetEndReachable ()
5543 end_reachable = true;
5547 // A place where execution can restart in a state machine
5548 public abstract class ResumableStatement : Statement
5551 protected Label resume_point;
5553 public Label PrepareForEmit (EmitContext ec)
5557 resume_point = ec.DefineLabel ();
5559 return resume_point;
5562 public virtual Label PrepareForDispose (EmitContext ec, Label end)
5567 public virtual void EmitForDispose (EmitContext ec, LocalBuilder pc, Label end, bool have_dispatcher)
5572 public abstract class TryFinallyBlock : ExceptionStatement
5574 protected Statement stmt;
5575 Label dispose_try_block;
5576 bool prepared_for_dispose, emitted_dispose;
5577 Method finally_host;
5579 protected TryFinallyBlock (Statement stmt, Location loc)
5587 public Statement Statement {
5595 protected abstract void EmitTryBody (EmitContext ec);
5596 public abstract void EmitFinallyBody (EmitContext ec);
5598 public override Label PrepareForDispose (EmitContext ec, Label end)
5600 if (!prepared_for_dispose) {
5601 prepared_for_dispose = true;
5602 dispose_try_block = ec.DefineLabel ();
5604 return dispose_try_block;
5607 protected sealed override void DoEmit (EmitContext ec)
5609 EmitTryBodyPrepare (ec);
5612 bool beginFinally = EmitBeginFinallyBlock (ec);
5614 Label start_finally = ec.DefineLabel ();
5615 if (resume_points != null && beginFinally) {
5616 var state_machine = (StateMachineInitializer) ec.CurrentAnonymousMethod;
5618 ec.Emit (OpCodes.Ldloc, state_machine.SkipFinally);
5619 ec.Emit (OpCodes.Brfalse_S, start_finally);
5620 ec.Emit (OpCodes.Endfinally);
5623 ec.MarkLabel (start_finally);
5625 if (finally_host != null) {
5626 finally_host.Define ();
5627 finally_host.PrepareEmit ();
5628 finally_host.Emit ();
5630 // Now it's safe to add, to close it properly and emit sequence points
5631 finally_host.Parent.AddMember (finally_host);
5633 var ce = new CallEmitter ();
5634 ce.InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, loc);
5635 ce.EmitPredefined (ec, finally_host.Spec, new Arguments (0), true);
5637 EmitFinallyBody (ec);
5641 ec.EndExceptionBlock ();
5644 public override void EmitForDispose (EmitContext ec, LocalBuilder pc, Label end, bool have_dispatcher)
5646 if (emitted_dispose)
5649 emitted_dispose = true;
5651 Label end_of_try = ec.DefineLabel ();
5653 // Ensure that the only way we can get into this code is through a dispatcher
5654 if (have_dispatcher)
5655 ec.Emit (OpCodes.Br, end);
5657 ec.BeginExceptionBlock ();
5659 ec.MarkLabel (dispose_try_block);
5661 Label[] labels = null;
5662 for (int i = 0; i < resume_points.Count; ++i) {
5663 ResumableStatement s = resume_points[i];
5664 Label ret = s.PrepareForDispose (ec, end_of_try);
5665 if (ret.Equals (end_of_try) && labels == null)
5667 if (labels == null) {
5668 labels = new Label[resume_points.Count];
5669 for (int j = 0; j < i; ++j)
5670 labels[j] = end_of_try;
5675 if (labels != null) {
5677 for (j = 1; j < labels.Length; ++j)
5678 if (!labels[0].Equals (labels[j]))
5680 bool emit_dispatcher = j < labels.Length;
5682 if (emit_dispatcher) {
5683 ec.Emit (OpCodes.Ldloc, pc);
5684 ec.EmitInt (first_resume_pc);
5685 ec.Emit (OpCodes.Sub);
5686 ec.Emit (OpCodes.Switch, labels);
5689 foreach (ResumableStatement s in resume_points)
5690 s.EmitForDispose (ec, pc, end_of_try, emit_dispatcher);
5693 ec.MarkLabel (end_of_try);
5695 ec.BeginFinallyBlock ();
5697 if (finally_host != null) {
5698 var ce = new CallEmitter ();
5699 ce.InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, loc);
5700 ce.EmitPredefined (ec, finally_host.Spec, new Arguments (0), true);
5702 EmitFinallyBody (ec);
5705 ec.EndExceptionBlock ();
5708 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
5710 var res = stmt.FlowAnalysis (fc);
5715 protected virtual bool EmitBeginFinallyBlock (EmitContext ec)
5717 ec.BeginFinallyBlock ();
5721 public override Reachability MarkReachable (Reachability rc)
5723 base.MarkReachable (rc);
5724 return Statement.MarkReachable (rc);
5727 public override bool Resolve (BlockContext bc)
5731 parent = bc.CurrentTryBlock;
5732 bc.CurrentTryBlock = this;
5734 using (bc.Set (ResolveContext.Options.TryScope)) {
5735 ok = stmt.Resolve (bc);
5738 bc.CurrentTryBlock = parent;
5741 // Finally block inside iterator is called from MoveNext and
5742 // Dispose methods that means we need to lift the block into
5743 // newly created host method to emit the body only once. The
5744 // original block then simply calls the newly generated method.
5746 if (bc.CurrentIterator != null && !bc.IsInProbingMode) {
5747 var b = stmt as Block;
5748 if (b != null && b.Explicit.HasYield) {
5749 finally_host = bc.CurrentIterator.CreateFinallyHost (this);
5753 return base.Resolve (bc) && ok;
5758 // Base class for blocks using exception handling
5760 public abstract class ExceptionStatement : ResumableStatement
5762 protected List<ResumableStatement> resume_points;
5763 protected int first_resume_pc;
5764 protected ExceptionStatement parent;
5766 protected ExceptionStatement (Location loc)
5771 protected virtual void EmitTryBodyPrepare (EmitContext ec)
5773 StateMachineInitializer state_machine = null;
5774 if (resume_points != null) {
5775 state_machine = (StateMachineInitializer) ec.CurrentAnonymousMethod;
5777 ec.EmitInt ((int) IteratorStorey.State.Running);
5778 ec.Emit (OpCodes.Stloc, state_machine.CurrentPC);
5781 ec.BeginExceptionBlock ();
5783 if (resume_points != null) {
5784 ec.MarkLabel (resume_point);
5786 // For normal control flow, we want to fall-through the Switch
5787 // So, we use CurrentPC rather than the $PC field, and initialize it to an outside value above
5788 ec.Emit (OpCodes.Ldloc, state_machine.CurrentPC);
5789 ec.EmitInt (first_resume_pc);
5790 ec.Emit (OpCodes.Sub);
5792 Label[] labels = new Label[resume_points.Count];
5793 for (int i = 0; i < resume_points.Count; ++i)
5794 labels[i] = resume_points[i].PrepareForEmit (ec);
5795 ec.Emit (OpCodes.Switch, labels);
5799 public virtual int AddResumePoint (ResumableStatement stmt, int pc, StateMachineInitializer stateMachine)
5801 if (parent != null) {
5802 // TODO: MOVE to virtual TryCatch
5803 var tc = this as TryCatch;
5804 var s = tc != null && tc.IsTryCatchFinally ? stmt : this;
5806 pc = parent.AddResumePoint (s, pc, stateMachine);
5808 pc = stateMachine.AddResumePoint (this);
5811 if (resume_points == null) {
5812 resume_points = new List<ResumableStatement> ();
5813 first_resume_pc = pc;
5816 if (pc != first_resume_pc + resume_points.Count)
5817 throw new InternalErrorException ("missed an intervening AddResumePoint?");
5819 resume_points.Add (stmt);
5824 public class Lock : TryFinallyBlock
5827 TemporaryVariableReference expr_copy;
5828 TemporaryVariableReference lock_taken;
5830 public Lock (Expression expr, Statement stmt, Location loc)
5836 public Expression Expr {
5842 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
5844 expr.FlowAnalysis (fc);
5845 return base.DoFlowAnalysis (fc);
5848 public override bool Resolve (BlockContext ec)
5850 expr = expr.Resolve (ec);
5854 if (!TypeSpec.IsReferenceType (expr.Type)) {
5855 ec.Report.Error (185, loc,
5856 "`{0}' is not a reference type as required by the lock statement",
5857 expr.Type.GetSignatureForError ());
5860 if (expr.Type.IsGenericParameter) {
5861 expr = Convert.ImplicitTypeParameterConversion (expr, (TypeParameterSpec)expr.Type, ec.BuiltinTypes.Object);
5864 VariableReference lv = expr as VariableReference;
5867 locked = lv.IsLockedByStatement;
5868 lv.IsLockedByStatement = true;
5875 // Have to keep original lock value around to unlock same location
5876 // in the case of original value has changed or is null
5878 expr_copy = TemporaryVariableReference.Create (ec.BuiltinTypes.Object, ec.CurrentBlock, loc);
5879 expr_copy.Resolve (ec);
5882 // Ensure Monitor methods are available
5884 if (ResolvePredefinedMethods (ec) > 1) {
5885 lock_taken = TemporaryVariableReference.Create (ec.BuiltinTypes.Bool, ec.CurrentBlock, loc);
5886 lock_taken.Resolve (ec);
5889 using (ec.Set (ResolveContext.Options.LockScope)) {
5894 lv.IsLockedByStatement = locked;
5900 protected override void EmitTryBodyPrepare (EmitContext ec)
5902 expr_copy.EmitAssign (ec, expr);
5904 if (lock_taken != null) {
5906 // Initialize ref variable
5908 lock_taken.EmitAssign (ec, new BoolLiteral (ec.BuiltinTypes, false, loc));
5911 // Monitor.Enter (expr_copy)
5913 expr_copy.Emit (ec);
5914 ec.Emit (OpCodes.Call, ec.Module.PredefinedMembers.MonitorEnter.Get ());
5917 base.EmitTryBodyPrepare (ec);
5920 protected override void EmitTryBody (EmitContext ec)
5923 // Monitor.Enter (expr_copy, ref lock_taken)
5925 if (lock_taken != null) {
5926 expr_copy.Emit (ec);
5927 lock_taken.LocalInfo.CreateBuilder (ec);
5928 lock_taken.AddressOf (ec, AddressOp.Load);
5929 ec.Emit (OpCodes.Call, ec.Module.PredefinedMembers.MonitorEnter_v4.Get ());
5932 Statement.Emit (ec);
5935 public override void EmitFinallyBody (EmitContext ec)
5938 // if (lock_taken) Monitor.Exit (expr_copy)
5940 Label skip = ec.DefineLabel ();
5942 if (lock_taken != null) {
5943 lock_taken.Emit (ec);
5944 ec.Emit (OpCodes.Brfalse_S, skip);
5947 expr_copy.Emit (ec);
5948 var m = ec.Module.PredefinedMembers.MonitorExit.Resolve (loc);
5950 ec.Emit (OpCodes.Call, m);
5952 ec.MarkLabel (skip);
5955 int ResolvePredefinedMethods (ResolveContext rc)
5957 // Try 4.0 Monitor.Enter (object, ref bool) overload first
5958 var m = rc.Module.PredefinedMembers.MonitorEnter_v4.Get ();
5962 m = rc.Module.PredefinedMembers.MonitorEnter.Get ();
5966 rc.Module.PredefinedMembers.MonitorEnter_v4.Resolve (loc);
5970 protected override void CloneTo (CloneContext clonectx, Statement t)
5972 Lock target = (Lock) t;
5974 target.expr = expr.Clone (clonectx);
5975 target.stmt = Statement.Clone (clonectx);
5978 public override object Accept (StructuralVisitor visitor)
5980 return visitor.Visit (this);
5985 public class Unchecked : Statement {
5988 public Unchecked (Block b, Location loc)
5995 public override bool Resolve (BlockContext ec)
5997 using (ec.With (ResolveContext.Options.AllCheckStateFlags, false))
5998 return Block.Resolve (ec);
6001 protected override void DoEmit (EmitContext ec)
6003 using (ec.With (EmitContext.Options.CheckedScope, false))
6007 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6009 return Block.FlowAnalysis (fc);
6012 public override Reachability MarkReachable (Reachability rc)
6014 base.MarkReachable (rc);
6015 return Block.MarkReachable (rc);
6018 protected override void CloneTo (CloneContext clonectx, Statement t)
6020 Unchecked target = (Unchecked) t;
6022 target.Block = clonectx.LookupBlock (Block);
6025 public override object Accept (StructuralVisitor visitor)
6027 return visitor.Visit (this);
6031 public class Checked : Statement {
6034 public Checked (Block b, Location loc)
6037 b.Unchecked = false;
6041 public override bool Resolve (BlockContext ec)
6043 using (ec.With (ResolveContext.Options.AllCheckStateFlags, true))
6044 return Block.Resolve (ec);
6047 protected override void DoEmit (EmitContext ec)
6049 using (ec.With (EmitContext.Options.CheckedScope, true))
6053 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6055 return Block.FlowAnalysis (fc);
6058 public override Reachability MarkReachable (Reachability rc)
6060 base.MarkReachable (rc);
6061 return Block.MarkReachable (rc);
6064 protected override void CloneTo (CloneContext clonectx, Statement t)
6066 Checked target = (Checked) t;
6068 target.Block = clonectx.LookupBlock (Block);
6071 public override object Accept (StructuralVisitor visitor)
6073 return visitor.Visit (this);
6077 public class Unsafe : Statement {
6080 public Unsafe (Block b, Location loc)
6083 Block.Unsafe = true;
6087 public override bool Resolve (BlockContext ec)
6089 if (ec.CurrentIterator != null)
6090 ec.Report.Error (1629, loc, "Unsafe code may not appear in iterators");
6092 using (ec.Set (ResolveContext.Options.UnsafeScope))
6093 return Block.Resolve (ec);
6096 protected override void DoEmit (EmitContext ec)
6101 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6103 return Block.FlowAnalysis (fc);
6106 public override Reachability MarkReachable (Reachability rc)
6108 base.MarkReachable (rc);
6109 return Block.MarkReachable (rc);
6112 protected override void CloneTo (CloneContext clonectx, Statement t)
6114 Unsafe target = (Unsafe) t;
6116 target.Block = clonectx.LookupBlock (Block);
6119 public override object Accept (StructuralVisitor visitor)
6121 return visitor.Visit (this);
6128 public class Fixed : Statement
6130 abstract class Emitter : ShimExpression
6132 protected LocalVariable vi;
6134 protected Emitter (Expression expr, LocalVariable li)
6140 public abstract void EmitExit (EmitContext ec);
6142 public override void FlowAnalysis (FlowAnalysisContext fc)
6144 expr.FlowAnalysis (fc);
6148 class ExpressionEmitter : Emitter {
6149 public ExpressionEmitter (Expression converted, LocalVariable li) :
6150 base (converted, li)
6154 protected override Expression DoResolve (ResolveContext rc)
6156 throw new NotImplementedException ();
6159 public override void Emit (EmitContext ec) {
6161 // Store pointer in pinned location
6167 public override void EmitExit (EmitContext ec)
6170 ec.Emit (OpCodes.Conv_U);
6175 class StringEmitter : Emitter
6177 LocalVariable pinned_string;
6179 public StringEmitter (Expression expr, LocalVariable li)
6184 protected override Expression DoResolve (ResolveContext rc)
6186 pinned_string = new LocalVariable (vi.Block, "$pinned",
6187 LocalVariable.Flags.FixedVariable | LocalVariable.Flags.CompilerGenerated | LocalVariable.Flags.Used,
6189 pinned_string.Type = rc.BuiltinTypes.String;
6191 eclass = ExprClass.Variable;
6192 type = rc.BuiltinTypes.Int;
6196 public override void Emit (EmitContext ec)
6198 pinned_string.CreateBuilder (ec);
6201 pinned_string.EmitAssign (ec);
6203 // TODO: Should use Binary::Add
6204 pinned_string.Emit (ec);
6205 ec.Emit (OpCodes.Conv_I);
6207 var m = ec.Module.PredefinedMembers.RuntimeHelpersOffsetToStringData.Resolve (loc);
6211 PropertyExpr pe = new PropertyExpr (m, pinned_string.Location);
6212 //pe.InstanceExpression = pinned_string;
6213 pe.Resolve (new ResolveContext (ec.MemberContext)).Emit (ec);
6215 ec.Emit (OpCodes.Add);
6219 public override void EmitExit (EmitContext ec)
6222 pinned_string.EmitAssign (ec);
6226 public class VariableDeclaration : BlockVariable
6228 public VariableDeclaration (FullNamedExpression type, LocalVariable li)
6233 protected override Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
6235 if (!Variable.Type.IsPointer && li == Variable) {
6236 bc.Report.Error (209, TypeExpression.Location,
6237 "The type of locals declared in a fixed statement must be a pointer type");
6242 // The rules for the possible declarators are pretty wise,
6243 // but the production on the grammar is more concise.
6245 // So we have to enforce these rules here.
6247 // We do not resolve before doing the case 1 test,
6248 // because the grammar is explicit in that the token &
6249 // is present, so we need to test for this particular case.
6252 if (initializer is Cast) {
6253 bc.Report.Error (254, initializer.Location, "The right hand side of a fixed statement assignment may not be a cast expression");
6257 initializer = initializer.Resolve (bc);
6259 if (initializer == null)
6265 if (initializer.Type.IsArray) {
6266 TypeSpec array_type = TypeManager.GetElementType (initializer.Type);
6269 // Provided that array_type is unmanaged,
6271 if (!TypeManager.VerifyUnmanaged (bc.Module, array_type, loc))
6275 // and T* is implicitly convertible to the
6276 // pointer type given in the fixed statement.
6278 ArrayPtr array_ptr = new ArrayPtr (initializer, array_type, loc);
6280 Expression converted = Convert.ImplicitConversionRequired (bc, array_ptr.Resolve (bc), li.Type, loc);
6281 if (converted == null)
6285 // fixed (T* e_ptr = (e == null || e.Length == 0) ? null : converted [0])
6287 converted = new Conditional (new BooleanExpression (new Binary (Binary.Operator.LogicalOr,
6288 new Binary (Binary.Operator.Equality, initializer, new NullLiteral (loc)),
6289 new Binary (Binary.Operator.Equality, new MemberAccess (initializer, "Length"), new IntConstant (bc.BuiltinTypes, 0, loc)))),
6290 new NullLiteral (loc),
6293 converted = converted.Resolve (bc);
6295 return new ExpressionEmitter (converted, li);
6301 if (initializer.Type.BuiltinType == BuiltinTypeSpec.Type.String) {
6302 return new StringEmitter (initializer, li).Resolve (bc);
6305 // Case 3: fixed buffer
6306 if (initializer is FixedBufferPtr) {
6307 return new ExpressionEmitter (initializer, li);
6311 // Case 4: & object.
6313 bool already_fixed = true;
6314 Unary u = initializer as Unary;
6315 if (u != null && u.Oper == Unary.Operator.AddressOf) {
6316 IVariableReference vr = u.Expr as IVariableReference;
6317 if (vr == null || !vr.IsFixed) {
6318 already_fixed = false;
6322 if (already_fixed) {
6323 bc.Report.Error (213, loc, "You cannot use the fixed statement to take the address of an already fixed expression");
6326 initializer = Convert.ImplicitConversionRequired (bc, initializer, li.Type, loc);
6327 return new ExpressionEmitter (initializer, li);
6332 VariableDeclaration decl;
6333 Statement statement;
6336 public Fixed (VariableDeclaration decl, Statement stmt, Location l)
6345 public Statement Statement {
6351 public BlockVariable Variables {
6359 public override bool Resolve (BlockContext bc)
6361 using (bc.Set (ResolveContext.Options.FixedInitializerScope)) {
6362 if (!decl.Resolve (bc))
6366 return statement.Resolve (bc);
6369 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6371 decl.FlowAnalysis (fc);
6372 return statement.FlowAnalysis (fc);
6375 protected override void DoEmit (EmitContext ec)
6377 decl.Variable.CreateBuilder (ec);
6378 decl.Initializer.Emit (ec);
6379 if (decl.Declarators != null) {
6380 foreach (var d in decl.Declarators) {
6381 d.Variable.CreateBuilder (ec);
6382 d.Initializer.Emit (ec);
6386 statement.Emit (ec);
6392 // Clear the pinned variable
6394 ((Emitter) decl.Initializer).EmitExit (ec);
6395 if (decl.Declarators != null) {
6396 foreach (var d in decl.Declarators) {
6397 ((Emitter)d.Initializer).EmitExit (ec);
6402 public override Reachability MarkReachable (Reachability rc)
6404 base.MarkReachable (rc);
6406 decl.MarkReachable (rc);
6408 rc = statement.MarkReachable (rc);
6410 // TODO: What if there is local exit?
6411 has_ret = rc.IsUnreachable;
6415 protected override void CloneTo (CloneContext clonectx, Statement t)
6417 Fixed target = (Fixed) t;
6419 target.decl = (VariableDeclaration) decl.Clone (clonectx);
6420 target.statement = statement.Clone (clonectx);
6423 public override object Accept (StructuralVisitor visitor)
6425 return visitor.Visit (this);
6429 public class Catch : Statement
6431 class FilterStatement : Statement
6433 readonly Catch ctch;
6435 public FilterStatement (Catch ctch)
6440 protected override void CloneTo (CloneContext clonectx, Statement target)
6444 protected override void DoEmit (EmitContext ec)
6446 if (ctch.li != null) {
6447 if (ctch.hoisted_temp != null)
6448 ctch.hoisted_temp.Emit (ec);
6452 if (!ctch.IsGeneral && ctch.type.Kind == MemberKind.TypeParameter)
6453 ec.Emit (OpCodes.Box, ctch.type);
6456 var expr_start = ec.DefineLabel ();
6457 var end = ec.DefineLabel ();
6459 ec.Emit (OpCodes.Brtrue_S, expr_start);
6461 ec.Emit (OpCodes.Br, end);
6462 ec.MarkLabel (expr_start);
6464 ctch.Filter.Emit (ec);
6467 ec.Emit (OpCodes.Endfilter);
6468 ec.BeginFilterHandler ();
6469 ec.Emit (OpCodes.Pop);
6472 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6474 ctch.Filter.FlowAnalysis (fc);
6478 public override bool Resolve (BlockContext bc)
6480 ctch.Filter = ctch.Filter.Resolve (bc);
6482 if (ctch.Filter != null) {
6483 if (ctch.Filter.ContainsEmitWithAwait ()) {
6484 bc.Report.Error (7094, ctch.Filter.Location, "The `await' operator cannot be used in the filter expression of a catch clause");
6487 var c = ctch.Filter as Constant;
6488 if (c != null && !c.IsDefaultValue) {
6489 bc.Report.Warning (7095, 1, ctch.Filter.Location, "Exception filter expression is a constant");
6497 ExplicitBlock block;
6499 FullNamedExpression type_expr;
6500 CompilerAssign assign;
6502 LocalTemporary hoisted_temp;
6504 public Catch (ExplicitBlock block, Location loc)
6512 public ExplicitBlock Block {
6518 public TypeSpec CatchType {
6524 public Expression Filter {
6528 public bool IsGeneral {
6530 return type_expr == null;
6534 public FullNamedExpression TypeExpression {
6543 public LocalVariable Variable {
6554 protected override void DoEmit (EmitContext ec)
6556 if (Filter != null) {
6557 ec.BeginExceptionFilterBlock ();
6558 ec.Emit (OpCodes.Isinst, IsGeneral ? ec.BuiltinTypes.Object : CatchType);
6561 EmitCatchVariableStore (ec);
6563 if (Block.HasAwait) {
6564 Block.EmitScopeInitialization (ec);
6573 ec.BeginCatchBlock (ec.BuiltinTypes.Object);
6575 ec.BeginCatchBlock (CatchType);
6578 EmitCatchVariableStore (ec);
6580 ec.Emit (OpCodes.Pop);
6583 if (!Block.HasAwait)
6587 void EmitCatchVariableStore (EmitContext ec)
6589 li.CreateBuilder (ec);
6592 // Special case hoisted catch variable, we have to use a temporary variable
6593 // to pass via anonymous storey initialization with the value still on top
6596 if (li.HoistedVariant != null) {
6597 hoisted_temp = new LocalTemporary (li.Type);
6598 hoisted_temp.Store (ec);
6600 // switch to assignment from temporary variable and not from top of the stack
6601 assign.UpdateSource (hoisted_temp);
6605 public override bool Resolve (BlockContext bc)
6607 using (bc.Set (ResolveContext.Options.CatchScope)) {
6608 if (type_expr == null) {
6609 if (CreateExceptionVariable (bc.Module.Compiler.BuiltinTypes.Object)) {
6610 Expression source = new EmptyExpression (li.Type);
6611 assign = new CompilerAssign (new LocalVariableReference (li, Location.Null), source, Location.Null);
6612 Block.AddScopeStatement (new StatementExpression (assign, Location.Null));
6615 type = type_expr.ResolveAsType (bc);
6620 CreateExceptionVariable (type);
6622 if (type.BuiltinType != BuiltinTypeSpec.Type.Exception && !TypeSpec.IsBaseClass (type, bc.BuiltinTypes.Exception, false)) {
6623 bc.Report.Error (155, loc, "The type caught or thrown must be derived from System.Exception");
6624 } else if (li != null) {
6626 li.PrepareAssignmentAnalysis (bc);
6628 // source variable is at the top of the stack
6629 Expression source = new EmptyExpression (li.Type);
6630 if (li.Type.IsGenericParameter)
6631 source = new UnboxCast (source, li.Type);
6634 // Uses Location.Null to hide from symbol file
6636 assign = new CompilerAssign (new LocalVariableReference (li, Location.Null), source, Location.Null);
6637 Block.AddScopeStatement (new StatementExpression (assign, Location.Null));
6641 if (Filter != null) {
6642 Block.AddScopeStatement (new FilterStatement (this));
6645 Block.SetCatchBlock ();
6646 return Block.Resolve (bc);
6650 bool CreateExceptionVariable (TypeSpec type)
6652 if (!Block.HasAwait)
6655 // TODO: Scan the block for rethrow expression
6656 //if (!Block.HasRethrow)
6659 li = LocalVariable.CreateCompilerGenerated (type, block, Location.Null);
6663 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6665 if (li != null && !li.IsCompilerGenerated) {
6666 fc.SetVariableAssigned (li.VariableInfo, true);
6669 return block.FlowAnalysis (fc);
6672 public override Reachability MarkReachable (Reachability rc)
6674 base.MarkReachable (rc);
6676 var c = Filter as Constant;
6677 if (c != null && c.IsDefaultValue)
6678 return Reachability.CreateUnreachable ();
6680 return block.MarkReachable (rc);
6683 protected override void CloneTo (CloneContext clonectx, Statement t)
6685 Catch target = (Catch) t;
6687 if (type_expr != null)
6688 target.type_expr = (FullNamedExpression) type_expr.Clone (clonectx);
6691 target.Filter = Filter.Clone (clonectx);
6693 target.block = (ExplicitBlock) clonectx.LookupBlock (block);
6697 public class TryFinally : TryFinallyBlock
6700 List<DefiniteAssignmentBitSet> try_exit_dat;
6701 List<Label> redirected_jumps;
6702 Label? start_fin_label;
6704 public TryFinally (Statement stmt, ExplicitBlock fini, Location loc)
6710 public ExplicitBlock FinallyBlock {
6716 public void RegisterForControlExitCheck (DefiniteAssignmentBitSet vector)
6718 if (try_exit_dat == null)
6719 try_exit_dat = new List<DefiniteAssignmentBitSet> ();
6721 try_exit_dat.Add (vector);
6724 public override bool Resolve (BlockContext bc)
6726 bool ok = base.Resolve (bc);
6728 fini.SetFinallyBlock ();
6729 using (bc.Set (ResolveContext.Options.FinallyScope)) {
6730 ok &= fini.Resolve (bc);
6736 protected override void EmitTryBody (EmitContext ec)
6738 if (fini.HasAwait) {
6739 if (ec.TryFinallyUnwind == null)
6740 ec.TryFinallyUnwind = new List<TryFinally> ();
6742 ec.TryFinallyUnwind.Add (this);
6744 ec.TryFinallyUnwind.Remove (this);
6746 if (start_fin_label != null)
6747 ec.MarkLabel (start_fin_label.Value);
6755 protected override bool EmitBeginFinallyBlock (EmitContext ec)
6760 return base.EmitBeginFinallyBlock (ec);
6763 public override void EmitFinallyBody (EmitContext ec)
6765 if (!fini.HasAwait) {
6771 // Emits catch block like
6773 // catch (object temp) {
6774 // this.exception_field = temp;
6777 var type = ec.BuiltinTypes.Object;
6778 ec.BeginCatchBlock (type);
6780 var temp = ec.GetTemporaryLocal (type);
6781 ec.Emit (OpCodes.Stloc, temp);
6783 var exception_field = ec.GetTemporaryField (type);
6785 ec.Emit (OpCodes.Ldloc, temp);
6786 exception_field.EmitAssignFromStack (ec);
6788 ec.EndExceptionBlock ();
6790 ec.FreeTemporaryLocal (temp, type);
6795 // Emits exception rethrow
6797 // if (this.exception_field != null)
6798 // throw this.exception_field;
6800 exception_field.Emit (ec);
6801 var skip_throw = ec.DefineLabel ();
6802 ec.Emit (OpCodes.Brfalse_S, skip_throw);
6803 exception_field.Emit (ec);
6804 ec.Emit (OpCodes.Throw);
6805 ec.MarkLabel (skip_throw);
6807 exception_field.IsAvailableForReuse = true;
6809 EmitUnwindFinallyTable (ec);
6812 bool IsParentBlock (Block block)
6814 for (Block b = fini; b != null; b = b.Parent) {
6822 public static Label EmitRedirectedJump (EmitContext ec, AsyncInitializer initializer, Label label, Block labelBlock)
6825 if (labelBlock != null) {
6826 for (idx = ec.TryFinallyUnwind.Count; idx != 0; --idx) {
6827 var fin = ec.TryFinallyUnwind [idx - 1];
6828 if (!fin.IsParentBlock (labelBlock))
6835 bool set_return_state = true;
6837 for (; idx < ec.TryFinallyUnwind.Count; ++idx) {
6838 var fin = ec.TryFinallyUnwind [idx];
6839 if (labelBlock != null && !fin.IsParentBlock (labelBlock))
6842 fin.EmitRedirectedExit (ec, label, initializer, set_return_state);
6843 set_return_state = false;
6845 if (fin.start_fin_label == null) {
6846 fin.start_fin_label = ec.DefineLabel ();
6849 label = fin.start_fin_label.Value;
6855 public static Label EmitRedirectedReturn (EmitContext ec, AsyncInitializer initializer)
6857 return EmitRedirectedJump (ec, initializer, initializer.BodyEnd, null);
6860 void EmitRedirectedExit (EmitContext ec, Label label, AsyncInitializer initializer, bool setReturnState)
6862 if (redirected_jumps == null) {
6863 redirected_jumps = new List<Label> ();
6865 // Add fallthrough label
6866 redirected_jumps.Add (ec.DefineLabel ());
6869 initializer.HoistedReturnState = ec.GetTemporaryField (ec.Module.Compiler.BuiltinTypes.Int, true);
6872 int index = redirected_jumps.IndexOf (label);
6874 redirected_jumps.Add (label);
6875 index = redirected_jumps.Count - 1;
6879 // Indicates we have captured exit jump
6881 if (setReturnState) {
6882 var value = new IntConstant (initializer.HoistedReturnState.Type, index, Location.Null);
6883 initializer.HoistedReturnState.EmitAssign (ec, value, false, false);
6888 // Emits state table of jumps outside of try block and reload of return
6889 // value when try block returns value
6891 void EmitUnwindFinallyTable (EmitContext ec)
6893 if (redirected_jumps == null)
6896 var initializer = (AsyncInitializer)ec.CurrentAnonymousMethod;
6897 initializer.HoistedReturnState.EmitLoad (ec);
6898 ec.Emit (OpCodes.Switch, redirected_jumps.ToArray ());
6900 // Mark fallthrough label
6901 ec.MarkLabel (redirected_jumps [0]);
6904 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6906 var da = fc.BranchDefiniteAssignment ();
6908 var tf = fc.TryFinally;
6909 fc.TryFinally = this;
6911 var res_stmt = Statement.FlowAnalysis (fc);
6915 var try_da = fc.DefiniteAssignment;
6916 fc.DefiniteAssignment = da;
6918 var res_fin = fini.FlowAnalysis (fc);
6920 if (try_exit_dat != null) {
6922 // try block has global exit but we need to run definite assignment check
6923 // for parameter block out parameter after finally block because it's always
6924 // executed before exit
6926 foreach (var try_da_part in try_exit_dat)
6927 fc.ParametersBlock.CheckControlExit (fc, fc.DefiniteAssignment | try_da_part);
6929 try_exit_dat = null;
6932 fc.DefiniteAssignment |= try_da;
6933 return res_stmt | res_fin;
6936 public override Reachability MarkReachable (Reachability rc)
6939 // Mark finally block first for any exit statement in try block
6940 // to know whether the code which follows finally is reachable
6942 return fini.MarkReachable (rc) | base.MarkReachable (rc);
6945 protected override void CloneTo (CloneContext clonectx, Statement t)
6947 TryFinally target = (TryFinally) t;
6949 target.stmt = stmt.Clone (clonectx);
6951 target.fini = (ExplicitBlock) clonectx.LookupBlock (fini);
6954 public override object Accept (StructuralVisitor visitor)
6956 return visitor.Visit (this);
6960 public class TryCatch : ExceptionStatement
6963 List<Catch> clauses;
6964 readonly bool inside_try_finally;
6965 List<Catch> catch_sm;
6967 public TryCatch (Block block, List<Catch> catch_clauses, Location l, bool inside_try_finally)
6971 this.clauses = catch_clauses;
6972 this.inside_try_finally = inside_try_finally;
6975 public List<Catch> Clauses {
6981 public bool IsTryCatchFinally {
6983 return inside_try_finally;
6987 public override bool Resolve (BlockContext bc)
6991 using (bc.Set (ResolveContext.Options.TryScope)) {
6992 parent = bc.CurrentTryBlock;
6994 if (IsTryCatchFinally) {
6995 ok = Block.Resolve (bc);
6997 using (bc.Set (ResolveContext.Options.TryWithCatchScope)) {
6998 bc.CurrentTryBlock = this;
6999 ok = Block.Resolve (bc);
7000 bc.CurrentTryBlock = parent;
7005 for (int i = 0; i < clauses.Count; ++i) {
7008 ok &= c.Resolve (bc);
7010 if (c.Block.HasAwait) {
7011 if (catch_sm == null)
7012 catch_sm = new List<Catch> ();
7017 if (c.Filter != null)
7020 TypeSpec resolved_type = c.CatchType;
7021 if (resolved_type == null)
7024 for (int ii = 0; ii < clauses.Count; ++ii) {
7028 if (clauses[ii].Filter != null)
7031 if (clauses[ii].IsGeneral) {
7032 if (resolved_type.BuiltinType != BuiltinTypeSpec.Type.Exception)
7035 if (!bc.Module.DeclaringAssembly.WrapNonExceptionThrows)
7038 if (!bc.Module.PredefinedAttributes.RuntimeCompatibility.IsDefined)
7041 bc.Report.Warning (1058, 1, c.loc,
7042 "A previous catch clause already catches all exceptions. All non-exceptions thrown will be wrapped in a `System.Runtime.CompilerServices.RuntimeWrappedException'");
7050 var ct = clauses[ii].CatchType;
7054 if (resolved_type == ct || TypeSpec.IsBaseClass (resolved_type, ct, true)) {
7055 bc.Report.Error (160, c.loc,
7056 "A previous catch clause already catches all exceptions of this or a super type `{0}'",
7057 ct.GetSignatureForError ());
7063 return base.Resolve (bc) && ok;
7066 protected sealed override void DoEmit (EmitContext ec)
7068 if (!inside_try_finally)
7069 EmitTryBodyPrepare (ec);
7073 LocalBuilder state_variable = null;
7074 foreach (Catch c in clauses) {
7077 if (catch_sm != null) {
7078 if (state_variable == null) {
7080 // Cannot reuse temp variable because non-catch path assumes the value is 0
7081 // which may not be true for reused local variable
7083 state_variable = ec.DeclareLocal (ec.Module.Compiler.BuiltinTypes.Int, false);
7086 var index = catch_sm.IndexOf (c);
7090 ec.EmitInt (index + 1);
7091 ec.Emit (OpCodes.Stloc, state_variable);
7095 if (!inside_try_finally)
7096 ec.EndExceptionBlock ();
7098 if (state_variable != null) {
7099 ec.Emit (OpCodes.Ldloc, state_variable);
7101 var labels = new Label [catch_sm.Count + 1];
7102 for (int i = 0; i < labels.Length; ++i) {
7103 labels [i] = ec.DefineLabel ();
7106 var end = ec.DefineLabel ();
7107 ec.Emit (OpCodes.Switch, labels);
7109 // 0 value is default label
7110 ec.MarkLabel (labels [0]);
7111 ec.Emit (OpCodes.Br, end);
7113 var atv = ec.AsyncThrowVariable;
7115 for (int i = 0; i < catch_sm.Count; ++i) {
7116 if (c != null && c.Block.HasReachableClosingBrace)
7117 ec.Emit (OpCodes.Br, end);
7119 ec.MarkLabel (labels [i + 1]);
7121 ec.AsyncThrowVariable = c.Variable;
7124 ec.AsyncThrowVariable = atv;
7130 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7132 var start_fc = fc.BranchDefiniteAssignment ();
7133 var res = Block.FlowAnalysis (fc);
7135 DefiniteAssignmentBitSet try_fc = res ? null : fc.DefiniteAssignment;
7137 foreach (var c in clauses) {
7138 fc.DefiniteAssignment = new DefiniteAssignmentBitSet (start_fc);
7139 if (!c.FlowAnalysis (fc)) {
7141 try_fc = fc.DefiniteAssignment;
7143 try_fc &= fc.DefiniteAssignment;
7149 fc.DefiniteAssignment = try_fc ?? start_fc;
7154 public override Reachability MarkReachable (Reachability rc)
7156 if (rc.IsUnreachable)
7159 base.MarkReachable (rc);
7161 var tc_rc = Block.MarkReachable (rc);
7163 foreach (var c in clauses)
7164 tc_rc &= c.MarkReachable (rc);
7169 protected override void CloneTo (CloneContext clonectx, Statement t)
7171 TryCatch target = (TryCatch) t;
7173 target.Block = clonectx.LookupBlock (Block);
7174 if (clauses != null){
7175 target.clauses = new List<Catch> ();
7176 foreach (Catch c in clauses)
7177 target.clauses.Add ((Catch) c.Clone (clonectx));
7181 public override object Accept (StructuralVisitor visitor)
7183 return visitor.Visit (this);
7187 public class Using : TryFinallyBlock
7189 public class VariableDeclaration : BlockVariable
7191 Statement dispose_call;
7193 public VariableDeclaration (FullNamedExpression type, LocalVariable li)
7198 public VariableDeclaration (LocalVariable li, Location loc)
7205 public VariableDeclaration (Expression expr)
7208 loc = expr.Location;
7214 public bool IsNested { get; private set; }
7218 public void EmitDispose (EmitContext ec)
7220 dispose_call.Emit (ec);
7223 public override bool Resolve (BlockContext bc)
7228 return base.Resolve (bc, false);
7231 public Expression ResolveExpression (BlockContext bc)
7233 var e = Initializer.Resolve (bc);
7237 li = LocalVariable.CreateCompilerGenerated (e.Type, bc.CurrentBlock, loc);
7238 Initializer = ResolveInitializer (bc, Variable, e);
7242 protected override Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
7244 if (li.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
7245 initializer = initializer.Resolve (bc);
7246 if (initializer == null)
7249 // Once there is dynamic used defer conversion to runtime even if we know it will never succeed
7250 Arguments args = new Arguments (1);
7251 args.Add (new Argument (initializer));
7252 initializer = new DynamicConversion (bc.BuiltinTypes.IDisposable, 0, args, initializer.Location).Resolve (bc);
7253 if (initializer == null)
7256 var var = LocalVariable.CreateCompilerGenerated (initializer.Type, bc.CurrentBlock, loc);
7257 dispose_call = CreateDisposeCall (bc, var);
7258 dispose_call.Resolve (bc);
7260 return base.ResolveInitializer (bc, li, new SimpleAssign (var.CreateReferenceExpression (bc, loc), initializer, loc));
7263 if (li == Variable) {
7264 CheckIDiposableConversion (bc, li, initializer);
7265 dispose_call = CreateDisposeCall (bc, li);
7266 dispose_call.Resolve (bc);
7269 return base.ResolveInitializer (bc, li, initializer);
7272 protected virtual void CheckIDiposableConversion (BlockContext bc, LocalVariable li, Expression initializer)
7276 if (type.BuiltinType != BuiltinTypeSpec.Type.IDisposable && !CanConvertToIDisposable (bc, type)) {
7277 if (type.IsNullableType) {
7278 // it's handled in CreateDisposeCall
7282 if (type != InternalType.ErrorType) {
7283 bc.Report.SymbolRelatedToPreviousError (type);
7284 var loc = type_expr == null ? initializer.Location : type_expr.Location;
7285 bc.Report.Error (1674, loc, "`{0}': type used in a using statement must be implicitly convertible to `System.IDisposable'",
7286 type.GetSignatureForError ());
7293 static bool CanConvertToIDisposable (BlockContext bc, TypeSpec type)
7295 var target = bc.BuiltinTypes.IDisposable;
7296 var tp = type as TypeParameterSpec;
7298 return Convert.ImplicitTypeParameterConversion (null, tp, target) != null;
7300 return type.ImplementsInterface (target, false);
7303 protected virtual Statement CreateDisposeCall (BlockContext bc, LocalVariable lv)
7305 var lvr = lv.CreateReferenceExpression (bc, lv.Location);
7307 var loc = lv.Location;
7309 var idt = bc.BuiltinTypes.IDisposable;
7310 var m = bc.Module.PredefinedMembers.IDisposableDispose.Resolve (loc);
7312 var dispose_mg = MethodGroupExpr.CreatePredefined (m, idt, loc);
7313 dispose_mg.InstanceExpression = type.IsNullableType ?
7314 new Cast (new TypeExpression (idt, loc), lvr, loc).Resolve (bc) :
7318 // Hide it from symbol file via null location
7320 Statement dispose = new StatementExpression (new Invocation (dispose_mg, null), Location.Null);
7322 // Add conditional call when disposing possible null variable
7323 if (!TypeSpec.IsValueType (type) || type.IsNullableType)
7324 dispose = new If (new Binary (Binary.Operator.Inequality, lvr, new NullLiteral (loc)), dispose, dispose.loc);
7329 public void ResolveDeclaratorInitializer (BlockContext bc)
7331 Initializer = base.ResolveInitializer (bc, Variable, Initializer);
7334 public Statement RewriteUsingDeclarators (BlockContext bc, Statement stmt)
7336 for (int i = declarators.Count - 1; i >= 0; --i) {
7337 var d = declarators [i];
7338 var vd = new VariableDeclaration (d.Variable, d.Variable.Location);
7339 vd.Initializer = d.Initializer;
7341 vd.dispose_call = CreateDisposeCall (bc, d.Variable);
7342 vd.dispose_call.Resolve (bc);
7344 stmt = new Using (vd, stmt, d.Variable.Location);
7351 public override object Accept (StructuralVisitor visitor)
7353 return visitor.Visit (this);
7357 VariableDeclaration decl;
7359 public Using (VariableDeclaration decl, Statement stmt, Location loc)
7365 public Using (Expression expr, Statement stmt, Location loc)
7368 this.decl = new VariableDeclaration (expr);
7373 public Expression Expr {
7375 return decl.Variable == null ? decl.Initializer : null;
7379 public BlockVariable Variables {
7387 public override void Emit (EmitContext ec)
7390 // Don't emit sequence point it will be set on variable declaration
7395 protected override void EmitTryBodyPrepare (EmitContext ec)
7398 base.EmitTryBodyPrepare (ec);
7401 protected override void EmitTryBody (EmitContext ec)
7406 public override void EmitFinallyBody (EmitContext ec)
7408 decl.EmitDispose (ec);
7411 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7413 decl.FlowAnalysis (fc);
7414 return stmt.FlowAnalysis (fc);
7417 public override Reachability MarkReachable (Reachability rc)
7419 decl.MarkReachable (rc);
7420 return base.MarkReachable (rc);
7423 public override bool Resolve (BlockContext ec)
7425 VariableReference vr;
7426 bool vr_locked = false;
7428 using (ec.Set (ResolveContext.Options.UsingInitializerScope)) {
7429 if (decl.Variable == null) {
7430 vr = decl.ResolveExpression (ec) as VariableReference;
7432 vr_locked = vr.IsLockedByStatement;
7433 vr.IsLockedByStatement = true;
7436 if (decl.IsNested) {
7437 decl.ResolveDeclaratorInitializer (ec);
7439 if (!decl.Resolve (ec))
7442 if (decl.Declarators != null) {
7443 stmt = decl.RewriteUsingDeclarators (ec, stmt);
7451 var ok = base.Resolve (ec);
7454 vr.IsLockedByStatement = vr_locked;
7459 protected override void CloneTo (CloneContext clonectx, Statement t)
7461 Using target = (Using) t;
7463 target.decl = (VariableDeclaration) decl.Clone (clonectx);
7464 target.stmt = stmt.Clone (clonectx);
7467 public override object Accept (StructuralVisitor visitor)
7469 return visitor.Visit (this);
7474 /// Implementation of the foreach C# statement
7476 public class Foreach : LoopStatement
7478 abstract class IteratorStatement : Statement
7480 protected readonly Foreach for_each;
7482 protected IteratorStatement (Foreach @foreach)
7484 this.for_each = @foreach;
7485 this.loc = @foreach.expr.Location;
7488 protected override void CloneTo (CloneContext clonectx, Statement target)
7490 throw new NotImplementedException ();
7493 public override void Emit (EmitContext ec)
7495 if (ec.EmitAccurateDebugInfo) {
7496 ec.Emit (OpCodes.Nop);
7502 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7504 throw new NotImplementedException ();
7508 sealed class ArrayForeach : IteratorStatement
7510 TemporaryVariableReference[] lengths;
7511 Expression [] length_exprs;
7512 StatementExpression[] counter;
7513 TemporaryVariableReference[] variables;
7515 TemporaryVariableReference copy;
7517 public ArrayForeach (Foreach @foreach, int rank)
7520 counter = new StatementExpression[rank];
7521 variables = new TemporaryVariableReference[rank];
7522 length_exprs = new Expression [rank];
7525 // Only use temporary length variables when dealing with
7526 // multi-dimensional arrays
7529 lengths = new TemporaryVariableReference [rank];
7532 public override bool Resolve (BlockContext ec)
7534 Block variables_block = for_each.variable.Block;
7535 copy = TemporaryVariableReference.Create (for_each.expr.Type, variables_block, loc);
7538 int rank = length_exprs.Length;
7539 Arguments list = new Arguments (rank);
7540 for (int i = 0; i < rank; i++) {
7541 var v = TemporaryVariableReference.Create (ec.BuiltinTypes.Int, variables_block, loc);
7543 counter[i] = new StatementExpression (new UnaryMutator (UnaryMutator.Mode.PostIncrement, v, Location.Null));
7544 counter[i].Resolve (ec);
7547 length_exprs [i] = new MemberAccess (copy, "Length").Resolve (ec);
7549 lengths[i] = TemporaryVariableReference.Create (ec.BuiltinTypes.Int, variables_block, loc);
7550 lengths[i].Resolve (ec);
7552 Arguments args = new Arguments (1);
7553 args.Add (new Argument (new IntConstant (ec.BuiltinTypes, i, loc)));
7554 length_exprs [i] = new Invocation (new MemberAccess (copy, "GetLength"), args).Resolve (ec);
7557 list.Add (new Argument (v));
7560 var access = new ElementAccess (copy, list, loc).Resolve (ec);
7565 if (for_each.type is VarExpr) {
7566 // Infer implicitly typed local variable from foreach array type
7567 var_type = access.Type;
7569 var_type = for_each.type.ResolveAsType (ec);
7571 if (var_type == null)
7574 access = Convert.ExplicitConversion (ec, access, var_type, loc);
7579 for_each.variable.Type = var_type;
7581 var variable_ref = new LocalVariableReference (for_each.variable, loc).Resolve (ec);
7582 if (variable_ref == null)
7585 for_each.body.AddScopeStatement (new StatementExpression (new CompilerAssign (variable_ref, access, Location.Null), for_each.type.Location));
7587 return for_each.body.Resolve (ec);
7590 protected override void DoEmit (EmitContext ec)
7592 copy.EmitAssign (ec, for_each.expr);
7594 int rank = length_exprs.Length;
7595 Label[] test = new Label [rank];
7596 Label[] loop = new Label [rank];
7598 for (int i = 0; i < rank; i++) {
7599 test [i] = ec.DefineLabel ();
7600 loop [i] = ec.DefineLabel ();
7602 if (lengths != null)
7603 lengths [i].EmitAssign (ec, length_exprs [i]);
7606 IntConstant zero = new IntConstant (ec.BuiltinTypes, 0, loc);
7607 for (int i = 0; i < rank; i++) {
7608 variables [i].EmitAssign (ec, zero);
7610 ec.Emit (OpCodes.Br, test [i]);
7611 ec.MarkLabel (loop [i]);
7614 for_each.body.Emit (ec);
7616 ec.MarkLabel (ec.LoopBegin);
7617 ec.Mark (for_each.expr.Location);
7619 for (int i = rank - 1; i >= 0; i--){
7620 counter [i].Emit (ec);
7622 ec.MarkLabel (test [i]);
7623 variables [i].Emit (ec);
7625 if (lengths != null)
7626 lengths [i].Emit (ec);
7628 length_exprs [i].Emit (ec);
7630 ec.Emit (OpCodes.Blt, loop [i]);
7633 ec.MarkLabel (ec.LoopEnd);
7637 sealed class CollectionForeach : IteratorStatement, OverloadResolver.IErrorHandler
7639 class RuntimeDispose : Using.VariableDeclaration
7641 public RuntimeDispose (LocalVariable lv, Location loc)
7647 protected override void CheckIDiposableConversion (BlockContext bc, LocalVariable li, Expression initializer)
7649 // Defered to runtime check
7652 protected override Statement CreateDisposeCall (BlockContext bc, LocalVariable lv)
7654 var idt = bc.BuiltinTypes.IDisposable;
7657 // Fabricates code like
7659 // if ((temp = vr as IDisposable) != null) temp.Dispose ();
7662 var dispose_variable = LocalVariable.CreateCompilerGenerated (idt, bc.CurrentBlock, loc);
7664 var idisaposable_test = new Binary (Binary.Operator.Inequality, new CompilerAssign (
7665 dispose_variable.CreateReferenceExpression (bc, loc),
7666 new As (lv.CreateReferenceExpression (bc, loc), new TypeExpression (dispose_variable.Type, loc), loc),
7667 loc), new NullLiteral (loc));
7669 var m = bc.Module.PredefinedMembers.IDisposableDispose.Resolve (loc);
7671 var dispose_mg = MethodGroupExpr.CreatePredefined (m, idt, loc);
7672 dispose_mg.InstanceExpression = dispose_variable.CreateReferenceExpression (bc, loc);
7674 Statement dispose = new StatementExpression (new Invocation (dispose_mg, null));
7675 return new If (idisaposable_test, dispose, loc);
7679 LocalVariable variable;
7681 Statement statement;
7682 ExpressionStatement init;
7683 TemporaryVariableReference enumerator_variable;
7684 bool ambiguous_getenumerator_name;
7686 public CollectionForeach (Foreach @foreach, LocalVariable var, Expression expr)
7689 this.variable = var;
7693 void Error_WrongEnumerator (ResolveContext rc, MethodSpec enumerator)
7695 rc.Report.SymbolRelatedToPreviousError (enumerator);
7696 rc.Report.Error (202, loc,
7697 "foreach statement requires that the return type `{0}' of `{1}' must have a suitable public MoveNext method and public Current property",
7698 enumerator.ReturnType.GetSignatureForError (), enumerator.GetSignatureForError ());
7701 MethodGroupExpr ResolveGetEnumerator (ResolveContext rc)
7704 // Option 1: Try to match by name GetEnumerator first
7706 var mexpr = Expression.MemberLookup (rc, false, expr.Type,
7707 "GetEnumerator", 0, Expression.MemberLookupRestrictions.ExactArity, loc); // TODO: What if CS0229 ?
7709 var mg = mexpr as MethodGroupExpr;
7711 mg.InstanceExpression = expr;
7712 Arguments args = new Arguments (0);
7713 mg = mg.OverloadResolve (rc, ref args, this, OverloadResolver.Restrictions.ProbingOnly | OverloadResolver.Restrictions.GetEnumeratorLookup);
7715 // For ambiguous GetEnumerator name warning CS0278 was reported, but Option 2 could still apply
7716 if (ambiguous_getenumerator_name)
7719 if (mg != null && !mg.BestCandidate.IsStatic && mg.BestCandidate.IsPublic) {
7725 // Option 2: Try to match using IEnumerable interfaces with preference of generic version
7728 PredefinedMember<MethodSpec> iface_candidate = null;
7729 var ptypes = rc.Module.PredefinedTypes;
7730 var gen_ienumerable = ptypes.IEnumerableGeneric;
7731 if (!gen_ienumerable.Define ())
7732 gen_ienumerable = null;
7734 var ifaces = t.Interfaces;
7735 if (ifaces != null) {
7736 foreach (var iface in ifaces) {
7737 if (gen_ienumerable != null && iface.MemberDefinition == gen_ienumerable.TypeSpec.MemberDefinition) {
7738 if (iface_candidate != null && iface_candidate != rc.Module.PredefinedMembers.IEnumerableGetEnumerator) {
7739 rc.Report.SymbolRelatedToPreviousError (expr.Type);
7740 rc.Report.Error (1640, loc,
7741 "foreach statement cannot operate on variables of type `{0}' because it contains multiple implementation of `{1}'. Try casting to a specific implementation",
7742 expr.Type.GetSignatureForError (), gen_ienumerable.TypeSpec.GetSignatureForError ());
7747 // TODO: Cache this somehow
7748 iface_candidate = new PredefinedMember<MethodSpec> (rc.Module, iface,
7749 MemberFilter.Method ("GetEnumerator", 0, ParametersCompiled.EmptyReadOnlyParameters, null));
7754 if (iface.BuiltinType == BuiltinTypeSpec.Type.IEnumerable && iface_candidate == null) {
7755 iface_candidate = rc.Module.PredefinedMembers.IEnumerableGetEnumerator;
7760 if (iface_candidate == null) {
7761 if (expr.Type != InternalType.ErrorType) {
7762 rc.Report.Error (1579, loc,
7763 "foreach statement cannot operate on variables of type `{0}' because it does not contain a definition for `{1}' or is inaccessible",
7764 expr.Type.GetSignatureForError (), "GetEnumerator");
7770 var method = iface_candidate.Resolve (loc);
7774 mg = MethodGroupExpr.CreatePredefined (method, expr.Type, loc);
7775 mg.InstanceExpression = expr;
7779 MethodGroupExpr ResolveMoveNext (ResolveContext rc, MethodSpec enumerator)
7781 var ms = MemberCache.FindMember (enumerator.ReturnType,
7782 MemberFilter.Method ("MoveNext", 0, ParametersCompiled.EmptyReadOnlyParameters, rc.BuiltinTypes.Bool),
7783 BindingRestriction.InstanceOnly) as MethodSpec;
7785 if (ms == null || !ms.IsPublic) {
7786 Error_WrongEnumerator (rc, enumerator);
7790 return MethodGroupExpr.CreatePredefined (ms, enumerator.ReturnType, expr.Location);
7793 PropertySpec ResolveCurrent (ResolveContext rc, MethodSpec enumerator)
7795 var ps = MemberCache.FindMember (enumerator.ReturnType,
7796 MemberFilter.Property ("Current", null),
7797 BindingRestriction.InstanceOnly) as PropertySpec;
7799 if (ps == null || !ps.IsPublic) {
7800 Error_WrongEnumerator (rc, enumerator);
7807 public override bool Resolve (BlockContext ec)
7809 bool is_dynamic = expr.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
7812 expr = Convert.ImplicitConversionRequired (ec, expr, ec.BuiltinTypes.IEnumerable, loc);
7813 } else if (expr.Type.IsNullableType) {
7814 expr = new Nullable.UnwrapCall (expr).Resolve (ec);
7817 var get_enumerator_mg = ResolveGetEnumerator (ec);
7818 if (get_enumerator_mg == null) {
7822 var get_enumerator = get_enumerator_mg.BestCandidate;
7823 enumerator_variable = TemporaryVariableReference.Create (get_enumerator.ReturnType, variable.Block, loc);
7824 enumerator_variable.Resolve (ec);
7826 // Prepare bool MoveNext ()
7827 var move_next_mg = ResolveMoveNext (ec, get_enumerator);
7828 if (move_next_mg == null) {
7832 move_next_mg.InstanceExpression = enumerator_variable;
7834 // Prepare ~T~ Current { get; }
7835 var current_prop = ResolveCurrent (ec, get_enumerator);
7836 if (current_prop == null) {
7840 var current_pe = new PropertyExpr (current_prop, loc) { InstanceExpression = enumerator_variable }.Resolve (ec);
7841 if (current_pe == null)
7844 VarExpr ve = for_each.type as VarExpr;
7848 // Source type is dynamic, set element type to dynamic too
7849 variable.Type = ec.BuiltinTypes.Dynamic;
7851 // Infer implicitly typed local variable from foreach enumerable type
7852 variable.Type = current_pe.Type;
7856 // Explicit cast of dynamic collection elements has to be done at runtime
7857 current_pe = EmptyCast.Create (current_pe, ec.BuiltinTypes.Dynamic);
7860 variable.Type = for_each.type.ResolveAsType (ec);
7862 if (variable.Type == null)
7865 current_pe = Convert.ExplicitConversion (ec, current_pe, variable.Type, loc);
7866 if (current_pe == null)
7870 var variable_ref = new LocalVariableReference (variable, loc).Resolve (ec);
7871 if (variable_ref == null)
7874 for_each.body.AddScopeStatement (new StatementExpression (new CompilerAssign (variable_ref, current_pe, Location.Null), for_each.type.Location));
7876 var init = new Invocation.Predefined (get_enumerator_mg, null);
7878 statement = new While (new BooleanExpression (new Invocation (move_next_mg, null)),
7879 for_each.body, Location.Null);
7881 var enum_type = enumerator_variable.Type;
7884 // Add Dispose method call when enumerator can be IDisposable
7886 if (!enum_type.ImplementsInterface (ec.BuiltinTypes.IDisposable, false)) {
7887 if (!enum_type.IsSealed && !TypeSpec.IsValueType (enum_type)) {
7889 // Runtime Dispose check
7891 var vd = new RuntimeDispose (enumerator_variable.LocalInfo, Location.Null);
7892 vd.Initializer = init;
7893 statement = new Using (vd, statement, Location.Null);
7896 // No Dispose call needed
7898 this.init = new SimpleAssign (enumerator_variable, init, Location.Null);
7899 this.init.Resolve (ec);
7903 // Static Dispose check
7905 var vd = new Using.VariableDeclaration (enumerator_variable.LocalInfo, Location.Null);
7906 vd.Initializer = init;
7907 statement = new Using (vd, statement, Location.Null);
7910 return statement.Resolve (ec);
7913 protected override void DoEmit (EmitContext ec)
7915 enumerator_variable.LocalInfo.CreateBuilder (ec);
7918 init.EmitStatement (ec);
7920 statement.Emit (ec);
7923 #region IErrorHandler Members
7925 bool OverloadResolver.IErrorHandler.AmbiguousCandidates (ResolveContext ec, MemberSpec best, MemberSpec ambiguous)
7927 ec.Report.SymbolRelatedToPreviousError (best);
7928 ec.Report.Warning (278, 2, expr.Location,
7929 "`{0}' contains ambiguous implementation of `{1}' pattern. Method `{2}' is ambiguous with method `{3}'",
7930 expr.Type.GetSignatureForError (), "enumerable",
7931 best.GetSignatureForError (), ambiguous.GetSignatureForError ());
7933 ambiguous_getenumerator_name = true;
7937 bool OverloadResolver.IErrorHandler.ArgumentMismatch (ResolveContext rc, MemberSpec best, Argument arg, int index)
7942 bool OverloadResolver.IErrorHandler.NoArgumentMatch (ResolveContext rc, MemberSpec best)
7947 bool OverloadResolver.IErrorHandler.TypeInferenceFailed (ResolveContext rc, MemberSpec best)
7956 LocalVariable variable;
7960 public Foreach (Expression type, LocalVariable var, Expression expr, Statement stmt, Block body, Location l)
7964 this.variable = var;
7970 public Expression Expr {
7971 get { return expr; }
7974 public Expression TypeExpression {
7975 get { return type; }
7978 public LocalVariable Variable {
7979 get { return variable; }
7982 public override Reachability MarkReachable (Reachability rc)
7984 base.MarkReachable (rc);
7986 body.MarkReachable (rc);
7991 public override bool Resolve (BlockContext ec)
7993 expr = expr.Resolve (ec);
7998 ec.Report.Error (186, loc, "Use of null is not valid in this context");
8002 body.AddStatement (Statement);
8004 if (expr.Type.BuiltinType == BuiltinTypeSpec.Type.String) {
8005 Statement = new ArrayForeach (this, 1);
8006 } else if (expr.Type is ArrayContainer) {
8007 Statement = new ArrayForeach (this, ((ArrayContainer) expr.Type).Rank);
8009 if (expr.eclass == ExprClass.MethodGroup || expr is AnonymousMethodExpression) {
8010 ec.Report.Error (446, expr.Location, "Foreach statement cannot operate on a `{0}'",
8011 expr.ExprClassName);
8015 Statement = new CollectionForeach (this, variable, expr);
8018 return base.Resolve (ec);
8021 protected override void DoEmit (EmitContext ec)
8023 Label old_begin = ec.LoopBegin, old_end = ec.LoopEnd;
8024 ec.LoopBegin = ec.DefineLabel ();
8025 ec.LoopEnd = ec.DefineLabel ();
8027 if (!(Statement is Block))
8028 ec.BeginCompilerScope ();
8030 variable.CreateBuilder (ec);
8032 Statement.Emit (ec);
8034 if (!(Statement is Block))
8037 ec.LoopBegin = old_begin;
8038 ec.LoopEnd = old_end;
8041 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
8043 expr.FlowAnalysis (fc);
8045 var da = fc.BranchDefiniteAssignment ();
8046 body.FlowAnalysis (fc);
8047 fc.DefiniteAssignment = da;
8051 protected override void CloneTo (CloneContext clonectx, Statement t)
8053 Foreach target = (Foreach) t;
8055 target.type = type.Clone (clonectx);
8056 target.expr = expr.Clone (clonectx);
8057 target.body = (Block) body.Clone (clonectx);
8058 target.Statement = Statement.Clone (clonectx);
8061 public override object Accept (StructuralVisitor visitor)
8063 return visitor.Visit (this);