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 || block_return_type == InternalType.ErrorType)
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 && async_type.TypeArguments [0] != ec.Module.PredefinedTypes.Task.TypeSpec) {
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 // Goto to unreachable label
1415 if (fc.AddReachedLabel (label))
1418 label.Block.ScanGotoJump (label, fc);
1422 public override Reachability MarkReachable (Reachability rc)
1424 if (rc.IsUnreachable)
1427 base.MarkReachable (rc);
1429 if (try_finally != null) {
1430 if (try_finally.FinallyBlock.HasReachableClosingBrace) {
1431 label.AddGotoReference (rc);
1436 label.AddGotoReference (rc);
1439 return Reachability.CreateUnreachable ();
1442 protected override void CloneTo (CloneContext clonectx, Statement target)
1447 protected override void DoEmit (EmitContext ec)
1449 // This should only happen for goto from try block to unrechable label
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 {
1489 public LabeledStatement (string name, Block block, Location l)
1496 public Label LabelTarget (EmitContext ec)
1501 label = ec.DefineLabel ();
1506 public Block Block {
1512 public string Name {
1513 get { return name; }
1516 protected override void CloneTo (CloneContext clonectx, Statement target)
1518 var t = (LabeledStatement) target;
1520 t.block = clonectx.RemapBlockCopy (block);
1523 public override bool Resolve (BlockContext bc)
1528 protected override void DoEmit (EmitContext ec)
1531 ec.MarkLabel (label);
1534 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1537 fc.Report.Warning (164, 2, loc, "This label has not been referenced");
1543 public override Reachability MarkReachable (Reachability rc)
1545 base.MarkReachable (rc);
1548 rc = new Reachability ();
1553 public void AddGotoReference (Reachability rc)
1561 block.ScanGotoJump (this);
1564 public override object Accept (StructuralVisitor visitor)
1566 return visitor.Visit (this);
1572 /// `goto default' statement
1574 public class GotoDefault : SwitchGoto
1576 public GotoDefault (Location l)
1581 public override bool Resolve (BlockContext bc)
1583 if (bc.Switch == null) {
1584 Error_GotoCaseRequiresSwitchBlock (bc);
1588 bc.Switch.RegisterGotoCase (null, null);
1594 protected override void DoEmit (EmitContext ec)
1596 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, ec.Switch.DefaultLabel.GetILLabel (ec));
1599 public override Reachability MarkReachable (Reachability rc)
1601 if (!rc.IsUnreachable) {
1602 var label = switch_statement.DefaultLabel;
1603 if (label.IsUnreachable) {
1604 label.MarkReachable (rc);
1605 switch_statement.Block.ScanGotoJump (label);
1609 return base.MarkReachable (rc);
1612 public override object Accept (StructuralVisitor visitor)
1614 return visitor.Visit (this);
1619 /// `goto case' statement
1621 public class GotoCase : SwitchGoto
1625 public GotoCase (Expression e, Location l)
1631 public Expression Expr {
1637 public SwitchLabel Label { get; set; }
1639 public override bool Resolve (BlockContext ec)
1641 if (ec.Switch == null) {
1642 Error_GotoCaseRequiresSwitchBlock (ec);
1646 Constant c = expr.ResolveLabelConstant (ec);
1652 if (ec.Switch.IsNullable && c is NullLiteral) {
1655 TypeSpec type = ec.Switch.SwitchType;
1656 res = c.Reduce (ec, type);
1658 c.Error_ValueCannotBeConverted (ec, type, true);
1662 if (!Convert.ImplicitStandardConversionExists (c, type))
1663 ec.Report.Warning (469, 2, loc,
1664 "The `goto case' value is not implicitly convertible to type `{0}'",
1665 type.GetSignatureForError ());
1669 ec.Switch.RegisterGotoCase (this, res);
1676 protected override void DoEmit (EmitContext ec)
1678 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, Label.GetILLabel (ec));
1681 protected override void CloneTo (CloneContext clonectx, Statement t)
1683 GotoCase target = (GotoCase) t;
1685 target.expr = expr.Clone (clonectx);
1688 public override Reachability MarkReachable (Reachability rc)
1690 if (!rc.IsUnreachable) {
1691 var label = switch_statement.FindLabel ((Constant) expr);
1692 if (label.IsUnreachable) {
1693 label.MarkReachable (rc);
1694 switch_statement.Block.ScanGotoJump (label);
1698 return base.MarkReachable (rc);
1701 public override object Accept (StructuralVisitor visitor)
1703 return visitor.Visit (this);
1707 public abstract class SwitchGoto : Statement
1709 protected bool unwind_protect;
1710 protected Switch switch_statement;
1712 protected SwitchGoto (Location loc)
1717 protected override void CloneTo (CloneContext clonectx, Statement target)
1722 public override bool Resolve (BlockContext bc)
1724 CheckExitBoundaries (bc, bc.Switch.Block);
1726 unwind_protect = bc.HasAny (ResolveContext.Options.TryScope | ResolveContext.Options.CatchScope);
1727 switch_statement = bc.Switch;
1732 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1737 public override Reachability MarkReachable (Reachability rc)
1739 base.MarkReachable (rc);
1740 return Reachability.CreateUnreachable ();
1743 protected void Error_GotoCaseRequiresSwitchBlock (BlockContext bc)
1745 bc.Report.Error (153, loc, "A goto case is only valid inside a switch statement");
1749 public class Throw : Statement {
1752 public Throw (Expression expr, Location l)
1758 public Expression Expr {
1764 public override bool Resolve (BlockContext ec)
1767 if (!ec.HasSet (ResolveContext.Options.CatchScope)) {
1768 ec.Report.Error (156, loc, "A throw statement with no arguments is not allowed outside of a catch clause");
1769 } else if (ec.HasSet (ResolveContext.Options.FinallyScope)) {
1770 for (var b = ec.CurrentBlock; b != null && !b.IsCatchBlock; b = b.Parent) {
1771 if (b.IsFinallyBlock) {
1772 ec.Report.Error (724, loc,
1773 "A throw statement with no arguments is not allowed inside of a finally clause nested inside of the innermost catch clause");
1782 expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
1787 var et = ec.BuiltinTypes.Exception;
1788 if (Convert.ImplicitConversionExists (ec, expr, et))
1789 expr = Convert.ImplicitConversion (ec, expr, et, loc);
1791 ec.Report.Error (155, expr.Location, "The type caught or thrown must be derived from System.Exception");
1796 protected override void DoEmit (EmitContext ec)
1799 var atv = ec.AsyncThrowVariable;
1801 if (atv.HoistedVariant != null) {
1802 atv.HoistedVariant.Emit (ec);
1807 ec.Emit (OpCodes.Throw);
1809 ec.Emit (OpCodes.Rethrow);
1814 ec.Emit (OpCodes.Throw);
1818 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1821 expr.FlowAnalysis (fc);
1826 public override Reachability MarkReachable (Reachability rc)
1828 base.MarkReachable (rc);
1829 return Reachability.CreateUnreachable ();
1832 protected override void CloneTo (CloneContext clonectx, Statement t)
1834 Throw target = (Throw) t;
1837 target.expr = expr.Clone (clonectx);
1840 public override object Accept (StructuralVisitor visitor)
1842 return visitor.Visit (this);
1846 public class Break : LocalExitStatement
1848 public Break (Location l)
1853 public override object Accept (StructuralVisitor visitor)
1855 return visitor.Visit (this);
1858 protected override void DoEmit (EmitContext ec)
1862 if (ec.TryFinallyUnwind != null) {
1863 var async_body = (AsyncInitializer) ec.CurrentAnonymousMethod;
1864 l = TryFinally.EmitRedirectedJump (ec, async_body, l, enclosing_loop.Statement as Block);
1867 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, l);
1870 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1872 enclosing_loop.AddEndDefiniteAssignment (fc);
1876 protected override bool DoResolve (BlockContext bc)
1878 enclosing_loop = bc.EnclosingLoopOrSwitch;
1879 return base.DoResolve (bc);
1882 public override Reachability MarkReachable (Reachability rc)
1884 base.MarkReachable (rc);
1886 if (!rc.IsUnreachable)
1887 enclosing_loop.SetEndReachable ();
1889 return Reachability.CreateUnreachable ();
1893 public class Continue : LocalExitStatement
1895 public Continue (Location l)
1900 public override object Accept (StructuralVisitor visitor)
1902 return visitor.Visit (this);
1906 protected override void DoEmit (EmitContext ec)
1908 var l = ec.LoopBegin;
1910 if (ec.TryFinallyUnwind != null) {
1911 var async_body = (AsyncInitializer) ec.CurrentAnonymousMethod;
1912 l = TryFinally.EmitRedirectedJump (ec, async_body, l, enclosing_loop.Statement as Block);
1915 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, l);
1918 protected override bool DoResolve (BlockContext bc)
1920 enclosing_loop = bc.EnclosingLoop;
1921 return base.DoResolve (bc);
1924 public override Reachability MarkReachable (Reachability rc)
1926 base.MarkReachable (rc);
1928 if (!rc.IsUnreachable)
1929 enclosing_loop.SetIteratorReachable ();
1931 return Reachability.CreateUnreachable ();
1935 public abstract class LocalExitStatement : ExitStatement
1937 protected LoopStatement enclosing_loop;
1939 protected LocalExitStatement (Location loc)
1944 protected override bool IsLocalExit {
1950 protected override void CloneTo (CloneContext clonectx, Statement t)
1955 protected override bool DoResolve (BlockContext bc)
1957 if (enclosing_loop == null) {
1958 bc.Report.Error (139, loc, "No enclosing loop out of which to break or continue");
1962 var block = enclosing_loop.Statement as Block;
1964 // Don't need to do extra checks for simple statements loops
1965 if (block != null) {
1966 CheckExitBoundaries (bc, block);
1973 public interface ILocalVariable
1975 void Emit (EmitContext ec);
1976 void EmitAssign (EmitContext ec);
1977 void EmitAddressOf (EmitContext ec);
1980 public interface INamedBlockVariable
1982 Block Block { get; }
1983 Expression CreateReferenceExpression (ResolveContext rc, Location loc);
1984 bool IsDeclared { get; }
1985 bool IsParameter { get; }
1986 Location Location { get; }
1989 public class BlockVariableDeclarator
1992 Expression initializer;
1994 public BlockVariableDeclarator (LocalVariable li, Expression initializer)
1996 if (li.Type != null)
1997 throw new ArgumentException ("Expected null variable type");
2000 this.initializer = initializer;
2005 public LocalVariable Variable {
2011 public Expression Initializer {
2016 initializer = value;
2022 public virtual BlockVariableDeclarator Clone (CloneContext cloneCtx)
2024 var t = (BlockVariableDeclarator) MemberwiseClone ();
2025 if (initializer != null)
2026 t.initializer = initializer.Clone (cloneCtx);
2032 public class BlockVariable : Statement
2034 Expression initializer;
2035 protected FullNamedExpression type_expr;
2036 protected LocalVariable li;
2037 protected List<BlockVariableDeclarator> declarators;
2040 public BlockVariable (FullNamedExpression type, LocalVariable li)
2042 this.type_expr = type;
2044 this.loc = type_expr.Location;
2047 protected BlockVariable (LocalVariable li)
2054 public List<BlockVariableDeclarator> Declarators {
2060 public Expression Initializer {
2065 initializer = value;
2069 public FullNamedExpression TypeExpression {
2075 public LocalVariable Variable {
2083 public void AddDeclarator (BlockVariableDeclarator decl)
2085 if (declarators == null)
2086 declarators = new List<BlockVariableDeclarator> ();
2088 declarators.Add (decl);
2091 static void CreateEvaluatorVariable (BlockContext bc, LocalVariable li)
2093 if (bc.Report.Errors != 0)
2096 var container = bc.CurrentMemberDefinition.Parent.PartialContainer;
2098 Field f = new Field (container, new TypeExpression (li.Type, li.Location), Modifiers.PUBLIC | Modifiers.STATIC,
2099 new MemberName (li.Name, li.Location), null);
2101 container.AddField (f);
2104 li.HoistedVariant = new HoistedEvaluatorVariable (f);
2108 public override bool Resolve (BlockContext bc)
2110 return Resolve (bc, true);
2113 public bool Resolve (BlockContext bc, bool resolveDeclaratorInitializers)
2115 if (type == null && !li.IsCompilerGenerated) {
2116 var vexpr = type_expr as VarExpr;
2119 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
2120 // same name exists or as a keyword when no type was found
2122 if (vexpr != null && !vexpr.IsPossibleType (bc)) {
2123 if (bc.Module.Compiler.Settings.Version < LanguageVersion.V_3)
2124 bc.Report.FeatureIsNotAvailable (bc.Module.Compiler, loc, "implicitly typed local variable");
2127 bc.Report.Error (821, loc, "A fixed statement cannot use an implicitly typed local variable");
2131 if (li.IsConstant) {
2132 bc.Report.Error (822, loc, "An implicitly typed local variable cannot be a constant");
2136 if (Initializer == null) {
2137 bc.Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
2141 if (declarators != null) {
2142 bc.Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
2146 Initializer = Initializer.Resolve (bc);
2147 if (Initializer != null) {
2148 ((VarExpr) type_expr).InferType (bc, Initializer);
2149 type = type_expr.Type;
2151 // Set error type to indicate the var was placed correctly but could
2154 // var a = missing ();
2156 type = InternalType.ErrorType;
2161 type = type_expr.ResolveAsType (bc);
2165 if (li.IsConstant && !type.IsConstantCompatible) {
2166 Const.Error_InvalidConstantType (type, loc, bc.Report);
2171 FieldBase.Error_VariableOfStaticClass (loc, li.Name, type, bc.Report);
2176 bool eval_global = bc.Module.Compiler.Settings.StatementMode && bc.CurrentBlock is ToplevelBlock;
2178 CreateEvaluatorVariable (bc, li);
2179 } else if (type != InternalType.ErrorType) {
2180 li.PrepareAssignmentAnalysis (bc);
2183 if (initializer != null) {
2184 initializer = ResolveInitializer (bc, li, initializer);
2185 // li.Variable.DefinitelyAssigned
2188 if (declarators != null) {
2189 foreach (var d in declarators) {
2190 d.Variable.Type = li.Type;
2192 CreateEvaluatorVariable (bc, d.Variable);
2193 } else if (type != InternalType.ErrorType) {
2194 d.Variable.PrepareAssignmentAnalysis (bc);
2197 if (d.Initializer != null && resolveDeclaratorInitializers) {
2198 d.Initializer = ResolveInitializer (bc, d.Variable, d.Initializer);
2199 // d.Variable.DefinitelyAssigned
2207 protected virtual Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
2209 var a = new SimpleAssign (li.CreateReferenceExpression (bc, li.Location), initializer, li.Location);
2210 return a.ResolveStatement (bc);
2213 protected override void DoEmit (EmitContext ec)
2215 li.CreateBuilder (ec);
2217 if (Initializer != null && !IsUnreachable)
2218 ((ExpressionStatement) Initializer).EmitStatement (ec);
2220 if (declarators != null) {
2221 foreach (var d in declarators) {
2222 d.Variable.CreateBuilder (ec);
2223 if (d.Initializer != null && !IsUnreachable) {
2224 ec.Mark (d.Variable.Location);
2225 ((ExpressionStatement) d.Initializer).EmitStatement (ec);
2231 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
2233 if (Initializer != null)
2234 Initializer.FlowAnalysis (fc);
2236 if (declarators != null) {
2237 foreach (var d in declarators) {
2238 if (d.Initializer != null)
2239 d.Initializer.FlowAnalysis (fc);
2246 public override Reachability MarkReachable (Reachability rc)
2248 var init = initializer as ExpressionStatement;
2250 init.MarkReachable (rc);
2252 return base.MarkReachable (rc);
2255 protected override void CloneTo (CloneContext clonectx, Statement target)
2257 BlockVariable t = (BlockVariable) target;
2259 if (type_expr != null)
2260 t.type_expr = (FullNamedExpression) type_expr.Clone (clonectx);
2262 if (initializer != null)
2263 t.initializer = initializer.Clone (clonectx);
2265 if (declarators != null) {
2266 t.declarators = null;
2267 foreach (var d in declarators)
2268 t.AddDeclarator (d.Clone (clonectx));
2272 public override object Accept (StructuralVisitor visitor)
2274 return visitor.Visit (this);
2278 public class BlockConstant : BlockVariable
2280 public BlockConstant (FullNamedExpression type, LocalVariable li)
2285 public override void Emit (EmitContext ec)
2287 // Nothing to emit, not even sequence point
2290 protected override Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
2292 initializer = initializer.Resolve (bc);
2293 if (initializer == null)
2296 var c = initializer as Constant;
2298 initializer.Error_ExpressionMustBeConstant (bc, initializer.Location, li.Name);
2302 c = c.ConvertImplicitly (li.Type);
2304 if (TypeSpec.IsReferenceType (li.Type))
2305 initializer.Error_ConstantCanBeInitializedWithNullOnly (bc, li.Type, initializer.Location, li.Name);
2307 initializer.Error_ValueCannotBeConverted (bc, li.Type, false);
2312 li.ConstantValue = c;
2316 public override object Accept (StructuralVisitor visitor)
2318 return visitor.Visit (this);
2323 // The information about a user-perceived local variable
2325 public sealed class LocalVariable : INamedBlockVariable, ILocalVariable
2332 AddressTaken = 1 << 2,
2333 CompilerGenerated = 1 << 3,
2335 ForeachVariable = 1 << 5,
2336 FixedVariable = 1 << 6,
2337 UsingVariable = 1 << 7,
2339 SymbolFileHidden = 1 << 9,
2341 ReadonlyMask = ForeachVariable | FixedVariable | UsingVariable
2345 readonly string name;
2346 readonly Location loc;
2347 readonly Block block;
2349 Constant const_value;
2351 public VariableInfo VariableInfo;
2352 HoistedVariable hoisted_variant;
2354 LocalBuilder builder;
2356 public LocalVariable (Block block, string name, Location loc)
2363 public LocalVariable (Block block, string name, Flags flags, Location loc)
2364 : this (block, name, loc)
2370 // Used by variable declarators
2372 public LocalVariable (LocalVariable li, string name, Location loc)
2373 : this (li.block, name, li.flags, loc)
2379 public bool AddressTaken {
2381 return (flags & Flags.AddressTaken) != 0;
2385 public Block Block {
2391 public Constant ConstantValue {
2396 const_value = value;
2401 // Hoisted local variable variant
2403 public HoistedVariable HoistedVariant {
2405 return hoisted_variant;
2408 hoisted_variant = value;
2412 public bool IsDeclared {
2414 return type != null;
2418 public bool IsCompilerGenerated {
2420 return (flags & Flags.CompilerGenerated) != 0;
2424 public bool IsConstant {
2426 return (flags & Flags.Constant) != 0;
2430 public bool IsLocked {
2432 return (flags & Flags.IsLocked) != 0;
2435 flags = value ? flags | Flags.IsLocked : flags & ~Flags.IsLocked;
2439 public bool IsThis {
2441 return (flags & Flags.IsThis) != 0;
2445 public bool IsFixed {
2447 return (flags & Flags.FixedVariable) != 0;
2450 flags = value ? flags | Flags.FixedVariable : flags & ~Flags.FixedVariable;
2454 bool INamedBlockVariable.IsParameter {
2460 public bool IsReadonly {
2462 return (flags & Flags.ReadonlyMask) != 0;
2466 public Location Location {
2472 public string Name {
2478 public TypeSpec Type {
2489 public void CreateBuilder (EmitContext ec)
2491 if ((flags & Flags.Used) == 0) {
2492 if (VariableInfo == null) {
2493 // Missing flow analysis or wrong variable flags
2494 throw new InternalErrorException ("VariableInfo is null and the variable `{0}' is not used", name);
2497 if (VariableInfo.IsEverAssigned)
2498 ec.Report.Warning (219, 3, Location, "The variable `{0}' is assigned but its value is never used", Name);
2500 ec.Report.Warning (168, 3, Location, "The variable `{0}' is declared but never used", Name);
2503 if (HoistedVariant != null)
2506 if (builder != null) {
2507 if ((flags & Flags.CompilerGenerated) != 0)
2510 // To avoid Used warning duplicates
2511 throw new InternalErrorException ("Already created variable `{0}'", name);
2515 // All fixed variabled are pinned, a slot has to be alocated
2517 builder = ec.DeclareLocal (Type, IsFixed);
2518 if ((flags & Flags.SymbolFileHidden) == 0)
2519 ec.DefineLocalVariable (name, builder);
2522 public static LocalVariable CreateCompilerGenerated (TypeSpec type, Block block, Location loc, bool writeToSymbolFile = false)
2524 LocalVariable li = new LocalVariable (block, GetCompilerGeneratedName (block), Flags.CompilerGenerated | Flags.Used, loc);
2525 if (!writeToSymbolFile)
2526 li.flags |= Flags.SymbolFileHidden;
2532 public Expression CreateReferenceExpression (ResolveContext rc, Location loc)
2534 if (IsConstant && const_value != null)
2535 return Constant.CreateConstantFromValue (Type, const_value.GetValue (), loc);
2537 return new LocalVariableReference (this, loc);
2540 public void Emit (EmitContext ec)
2542 // TODO: Need something better for temporary variables
2543 if ((flags & Flags.CompilerGenerated) != 0)
2546 ec.Emit (OpCodes.Ldloc, builder);
2549 public void EmitAssign (EmitContext ec)
2551 // TODO: Need something better for temporary variables
2552 if ((flags & Flags.CompilerGenerated) != 0)
2555 ec.Emit (OpCodes.Stloc, builder);
2558 public void EmitAddressOf (EmitContext ec)
2560 // TODO: Need something better for temporary variables
2561 if ((flags & Flags.CompilerGenerated) != 0)
2564 ec.Emit (OpCodes.Ldloca, builder);
2567 public static string GetCompilerGeneratedName (Block block)
2569 // HACK: Debugger depends on the name semantics
2570 return "$locvar" + block.ParametersBlock.TemporaryLocalsCount++.ToString ("X");
2573 public string GetReadOnlyContext ()
2575 switch (flags & Flags.ReadonlyMask) {
2576 case Flags.FixedVariable:
2577 return "fixed variable";
2578 case Flags.ForeachVariable:
2579 return "foreach iteration variable";
2580 case Flags.UsingVariable:
2581 return "using variable";
2584 throw new InternalErrorException ("Variable is not readonly");
2587 public bool IsThisAssigned (FlowAnalysisContext fc, Block block)
2589 if (VariableInfo == null)
2590 throw new Exception ();
2592 if (IsAssigned (fc))
2595 return VariableInfo.IsFullyInitialized (fc, block.StartLocation);
2598 public bool IsAssigned (FlowAnalysisContext fc)
2600 return fc.IsDefinitelyAssigned (VariableInfo);
2603 public void PrepareAssignmentAnalysis (BlockContext bc)
2606 // No need to run assignment analysis for these guys
2608 if ((flags & (Flags.Constant | Flags.ReadonlyMask | Flags.CompilerGenerated)) != 0)
2611 VariableInfo = VariableInfo.Create (bc, this);
2615 // Mark the variables as referenced in the user code
2617 public void SetIsUsed ()
2619 flags |= Flags.Used;
2622 public void SetHasAddressTaken ()
2624 flags |= (Flags.AddressTaken | Flags.Used);
2627 public override string ToString ()
2629 return string.Format ("LocalInfo ({0},{1},{2},{3})", name, type, VariableInfo, Location);
2634 /// Block represents a C# block.
2638 /// This class is used in a number of places: either to represent
2639 /// explicit blocks that the programmer places or implicit blocks.
2641 /// Implicit blocks are used as labels or to introduce variable
2644 /// Top-level blocks derive from Block, and they are called ToplevelBlock
2645 /// they contain extra information that is not necessary on normal blocks.
2647 public class Block : Statement {
2654 HasCapturedVariable = 64,
2655 HasCapturedThis = 1 << 7,
2656 IsExpressionTree = 1 << 8,
2657 CompilerGenerated = 1 << 9,
2658 HasAsyncModifier = 1 << 10,
2660 YieldBlock = 1 << 12,
2661 AwaitBlock = 1 << 13,
2662 FinallyBlock = 1 << 14,
2663 CatchBlock = 1 << 15,
2665 NoFlowAnalysis = 1 << 21,
2666 InitializationEmitted = 1 << 22
2669 public Block Parent;
2670 public Location StartLocation;
2671 public Location EndLocation;
2673 public ExplicitBlock Explicit;
2674 public ParametersBlock ParametersBlock;
2676 protected Flags flags;
2679 // The statements in this block
2681 protected List<Statement> statements;
2683 protected List<Statement> scope_initializers;
2685 int? resolving_init_idx;
2691 public int ID = id++;
2693 static int clone_id_counter;
2697 // int assignable_slots;
2699 public Block (Block parent, Location start, Location end)
2700 : this (parent, 0, start, end)
2704 public Block (Block parent, Flags flags, Location start, Location end)
2706 if (parent != null) {
2707 // the appropriate constructors will fixup these fields
2708 ParametersBlock = parent.ParametersBlock;
2709 Explicit = parent.Explicit;
2712 this.Parent = parent;
2714 this.StartLocation = start;
2715 this.EndLocation = end;
2717 statements = new List<Statement> (4);
2719 this.original = this;
2724 public Block Original {
2733 public bool IsCompilerGenerated {
2734 get { return (flags & Flags.CompilerGenerated) != 0; }
2735 set { flags = value ? flags | Flags.CompilerGenerated : flags & ~Flags.CompilerGenerated; }
2739 public bool IsCatchBlock {
2741 return (flags & Flags.CatchBlock) != 0;
2745 public bool IsFinallyBlock {
2747 return (flags & Flags.FinallyBlock) != 0;
2751 public bool Unchecked {
2752 get { return (flags & Flags.Unchecked) != 0; }
2753 set { flags = value ? flags | Flags.Unchecked : flags & ~Flags.Unchecked; }
2756 public bool Unsafe {
2757 get { return (flags & Flags.Unsafe) != 0; }
2758 set { flags |= Flags.Unsafe; }
2761 public List<Statement> Statements {
2762 get { return statements; }
2767 public void SetEndLocation (Location loc)
2772 public void AddLabel (LabeledStatement target)
2774 ParametersBlock.TopBlock.AddLabel (target.Name, target);
2777 public void AddLocalName (LocalVariable li)
2779 AddLocalName (li.Name, li);
2782 public void AddLocalName (string name, INamedBlockVariable li)
2784 ParametersBlock.TopBlock.AddLocalName (name, li, false);
2787 public virtual void Error_AlreadyDeclared (string name, INamedBlockVariable variable, string reason)
2789 if (reason == null) {
2790 Error_AlreadyDeclared (name, variable);
2794 ParametersBlock.TopBlock.Report.Error (136, variable.Location,
2795 "A local variable named `{0}' cannot be declared in this scope because it would give a different meaning " +
2796 "to `{0}', which is already used in a `{1}' scope to denote something else",
2800 public virtual void Error_AlreadyDeclared (string name, INamedBlockVariable variable)
2802 var pi = variable as ParametersBlock.ParameterInfo;
2804 pi.Parameter.Error_DuplicateName (ParametersBlock.TopBlock.Report);
2806 ParametersBlock.TopBlock.Report.Error (128, variable.Location,
2807 "A local variable named `{0}' is already defined in this scope", name);
2811 public virtual void Error_AlreadyDeclaredTypeParameter (string name, Location loc)
2813 ParametersBlock.TopBlock.Report.Error (412, loc,
2814 "The type parameter name `{0}' is the same as local variable or parameter name",
2819 // It should be used by expressions which require to
2820 // register a statement during resolve process.
2822 public void AddScopeStatement (Statement s)
2824 if (scope_initializers == null)
2825 scope_initializers = new List<Statement> ();
2828 // Simple recursive helper, when resolve scope initializer another
2829 // new scope initializer can be added, this ensures it's initialized
2830 // before existing one. For now this can happen with expression trees
2831 // in base ctor initializer only
2833 if (resolving_init_idx.HasValue) {
2834 scope_initializers.Insert (resolving_init_idx.Value, s);
2835 ++resolving_init_idx;
2837 scope_initializers.Add (s);
2841 public void InsertStatement (int index, Statement s)
2843 statements.Insert (index, s);
2846 public void AddStatement (Statement s)
2851 public LabeledStatement LookupLabel (string name)
2853 return ParametersBlock.GetLabel (name, this);
2856 public override Reachability MarkReachable (Reachability rc)
2858 if (rc.IsUnreachable)
2861 MarkReachableScope (rc);
2863 foreach (var s in statements) {
2864 rc = s.MarkReachable (rc);
2865 if (rc.IsUnreachable) {
2866 if ((flags & Flags.ReachableEnd) != 0)
2867 return new Reachability ();
2873 flags |= Flags.ReachableEnd;
2878 public void MarkReachableScope (Reachability rc)
2880 base.MarkReachable (rc);
2882 if (scope_initializers != null) {
2883 foreach (var si in scope_initializers)
2884 si.MarkReachable (rc);
2888 public override bool Resolve (BlockContext bc)
2890 if ((flags & Flags.Resolved) != 0)
2893 Block prev_block = bc.CurrentBlock;
2894 bc.CurrentBlock = this;
2897 // Compiler generated scope statements
2899 if (scope_initializers != null) {
2900 for (resolving_init_idx = 0; resolving_init_idx < scope_initializers.Count; ++resolving_init_idx) {
2901 scope_initializers[resolving_init_idx.Value].Resolve (bc);
2904 resolving_init_idx = null;
2908 int statement_count = statements.Count;
2909 for (int ix = 0; ix < statement_count; ix++){
2910 Statement s = statements [ix];
2912 if (!s.Resolve (bc)) {
2914 statements [ix] = new EmptyStatement (s.loc);
2919 bc.CurrentBlock = prev_block;
2921 flags |= Flags.Resolved;
2925 protected override void DoEmit (EmitContext ec)
2927 for (int ix = 0; ix < statements.Count; ix++){
2928 statements [ix].Emit (ec);
2932 public override void Emit (EmitContext ec)
2934 if (scope_initializers != null)
2935 EmitScopeInitializers (ec);
2940 protected void EmitScopeInitializers (EmitContext ec)
2942 foreach (Statement s in scope_initializers)
2946 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
2948 if (scope_initializers != null) {
2949 foreach (var si in scope_initializers)
2950 si.FlowAnalysis (fc);
2953 return DoFlowAnalysis (fc, 0);
2956 bool DoFlowAnalysis (FlowAnalysisContext fc, int startIndex)
2958 bool end_unreachable = !reachable;
2959 bool goto_flow_analysis = startIndex != 0;
2960 for (; startIndex < statements.Count; ++startIndex) {
2961 var s = statements[startIndex];
2963 end_unreachable = s.FlowAnalysis (fc);
2964 if (s.IsUnreachable) {
2965 statements [startIndex] = RewriteUnreachableStatement (s);
2970 // Statement end reachability is needed mostly due to goto support. Consider
2979 // X label is reachable only via goto not as another statement after if. We need
2980 // this for flow-analysis only to carry variable info correctly.
2982 if (end_unreachable) {
2983 bool after_goto_case = goto_flow_analysis && s is GotoCase;
2985 var f = s as TryFinally;
2986 if (f != null && !f.FinallyBlock.HasReachableClosingBrace) {
2988 // Special case for try-finally with unreachable code after
2989 // finally block. Try block has to include leave opcode but there is
2990 // no label to leave to after unreachable finally block closing
2991 // brace. This sentinel ensures there is always IL instruction to
2992 // leave to even if we know it'll never be reached.
2994 statements.Insert (startIndex + 1, new SentinelStatement ());
2996 for (++startIndex; startIndex < statements.Count; ++startIndex) {
2997 s = statements [startIndex];
2998 if (s is SwitchLabel) {
2999 if (!after_goto_case)
3000 s.FlowAnalysis (fc);
3005 if (s.IsUnreachable) {
3006 s.FlowAnalysis (fc);
3007 statements [startIndex] = RewriteUnreachableStatement (s);
3013 // Idea is to stop after goto case because goto case will always have at least same
3014 // variable assigned as switch case label. This saves a lot for complex goto case tests
3016 if (after_goto_case)
3022 var lb = s as LabeledStatement;
3023 if (lb != null && fc.AddReachedLabel (lb))
3028 // The condition should be true unless there is forward jumping goto
3030 // if (this is ExplicitBlock && end_unreachable != Explicit.HasReachableClosingBrace)
3033 return !Explicit.HasReachableClosingBrace;
3036 static Statement RewriteUnreachableStatement (Statement s)
3038 // LAMESPEC: It's not clear whether declararion statement should be part of reachability
3039 // analysis. Even csc report unreachable warning for it but it's actually used hence
3040 // we try to emulate this behaviour
3048 if (s is BlockVariable || s is EmptyStatement || s is SentinelStatement)
3051 return new EmptyStatement (s.loc);
3054 public void ScanGotoJump (Statement label)
3057 for (i = 0; i < statements.Count; ++i) {
3058 if (statements[i] == label)
3062 var rc = new Reachability ();
3063 for (++i; i < statements.Count; ++i) {
3064 var s = statements[i];
3065 rc = s.MarkReachable (rc);
3066 if (rc.IsUnreachable)
3070 flags |= Flags.ReachableEnd;
3073 public void ScanGotoJump (Statement label, FlowAnalysisContext fc)
3076 for (i = 0; i < statements.Count; ++i) {
3077 if (statements[i] == label)
3081 DoFlowAnalysis (fc, ++i);
3085 public override string ToString ()
3087 return String.Format ("{0}: ID={1} Clone={2} Location={3}", GetType (), ID, clone_id != 0, StartLocation);
3091 protected override void CloneTo (CloneContext clonectx, Statement t)
3093 Block target = (Block) t;
3095 target.clone_id = ++clone_id_counter;
3098 clonectx.AddBlockMap (this, target);
3099 if (original != this)
3100 clonectx.AddBlockMap (original, target);
3102 target.ParametersBlock = (ParametersBlock) (ParametersBlock == this ? target : clonectx.RemapBlockCopy (ParametersBlock));
3103 target.Explicit = (ExplicitBlock) (Explicit == this ? target : clonectx.LookupBlock (Explicit));
3106 target.Parent = clonectx.RemapBlockCopy (Parent);
3108 target.statements = new List<Statement> (statements.Count);
3109 foreach (Statement s in statements)
3110 target.statements.Add (s.Clone (clonectx));
3113 public override object Accept (StructuralVisitor visitor)
3115 return visitor.Visit (this);
3119 public class ExplicitBlock : Block
3121 protected AnonymousMethodStorey am_storey;
3123 public ExplicitBlock (Block parent, Location start, Location end)
3124 : this (parent, (Flags) 0, start, end)
3128 public ExplicitBlock (Block parent, Flags flags, Location start, Location end)
3129 : base (parent, flags, start, end)
3131 this.Explicit = this;
3136 public AnonymousMethodStorey AnonymousMethodStorey {
3142 public bool HasAwait {
3144 return (flags & Flags.AwaitBlock) != 0;
3148 public bool HasCapturedThis {
3150 flags = value ? flags | Flags.HasCapturedThis : flags & ~Flags.HasCapturedThis;
3153 return (flags & Flags.HasCapturedThis) != 0;
3158 // Used to indicate that the block has reference to parent
3159 // block and cannot be made static when defining anonymous method
3161 public bool HasCapturedVariable {
3163 flags = value ? flags | Flags.HasCapturedVariable : flags & ~Flags.HasCapturedVariable;
3166 return (flags & Flags.HasCapturedVariable) != 0;
3170 public bool HasReachableClosingBrace {
3172 return (flags & Flags.ReachableEnd) != 0;
3175 flags = value ? flags | Flags.ReachableEnd : flags & ~Flags.ReachableEnd;
3179 public bool HasYield {
3181 return (flags & Flags.YieldBlock) != 0;
3188 // Creates anonymous method storey in current block
3190 public AnonymousMethodStorey CreateAnonymousMethodStorey (ResolveContext ec)
3193 // Return same story for iterator and async blocks unless we are
3194 // in nested anonymous method
3196 if (ec.CurrentAnonymousMethod is StateMachineInitializer && ParametersBlock.Original == ec.CurrentAnonymousMethod.Block.Original)
3197 return ec.CurrentAnonymousMethod.Storey;
3199 if (am_storey == null) {
3200 MemberBase mc = ec.MemberContext as MemberBase;
3203 // Creates anonymous method storey for this block
3205 am_storey = new AnonymousMethodStorey (this, ec.CurrentMemberDefinition.Parent.PartialContainer, mc, ec.CurrentTypeParameters, "AnonStorey", MemberKind.Class);
3211 public void EmitScopeInitialization (EmitContext ec)
3213 if ((flags & Flags.InitializationEmitted) != 0)
3216 if (am_storey != null) {
3217 DefineStoreyContainer (ec, am_storey);
3218 am_storey.EmitStoreyInstantiation (ec, this);
3221 if (scope_initializers != null)
3222 EmitScopeInitializers (ec);
3224 flags |= Flags.InitializationEmitted;
3227 public override void Emit (EmitContext ec)
3232 EmitScopeInitialization (ec);
3234 if (ec.EmitAccurateDebugInfo && !IsCompilerGenerated && ec.Mark (StartLocation)) {
3235 ec.Emit (OpCodes.Nop);
3243 if (ec.EmitAccurateDebugInfo && HasReachableClosingBrace && !(this is ParametersBlock) &&
3244 !IsCompilerGenerated && ec.Mark (EndLocation)) {
3245 ec.Emit (OpCodes.Nop);
3249 protected void DefineStoreyContainer (EmitContext ec, AnonymousMethodStorey storey)
3251 if (ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.Storey != null) {
3252 storey.SetNestedStoryParent (ec.CurrentAnonymousMethod.Storey);
3253 storey.Mutator = ec.CurrentAnonymousMethod.Storey.Mutator;
3257 // Creates anonymous method storey
3259 storey.CreateContainer ();
3260 storey.DefineContainer ();
3262 if (Original.Explicit.HasCapturedThis && Original.ParametersBlock.TopBlock.ThisReferencesFromChildrenBlock != null) {
3265 // Only first storey in path will hold this reference. All children blocks will
3266 // reference it indirectly using $ref field
3268 for (Block b = Original.Explicit; b != null; b = b.Parent) {
3269 if (b.Parent != null) {
3270 var s = b.Parent.Explicit.AnonymousMethodStorey;
3272 storey.HoistedThis = s.HoistedThis;
3277 if (b.Explicit == b.Explicit.ParametersBlock && b.Explicit.ParametersBlock.StateMachine != null) {
3278 if (storey.HoistedThis == null)
3279 storey.HoistedThis = b.Explicit.ParametersBlock.StateMachine.HoistedThis;
3281 if (storey.HoistedThis != null)
3287 // We are the first storey on path and 'this' has to be hoisted
3289 if (storey.HoistedThis == null || !(storey.Parent is HoistedStoreyClass)) {
3290 foreach (ExplicitBlock ref_block in Original.ParametersBlock.TopBlock.ThisReferencesFromChildrenBlock) {
3292 // ThisReferencesFromChildrenBlock holds all reference even if they
3293 // are not on this path. It saves some memory otherwise it'd have to
3294 // be in every explicit block. We run this check to see if the reference
3295 // is valid for this storey
3297 Block block_on_path = ref_block;
3298 for (; block_on_path != null && block_on_path != Original; block_on_path = block_on_path.Parent);
3300 if (block_on_path == null)
3303 if (storey.HoistedThis == null) {
3304 storey.AddCapturedThisField (ec, null);
3307 for (ExplicitBlock b = ref_block; b.AnonymousMethodStorey != storey; b = b.Parent.Explicit) {
3309 AnonymousMethodStorey b_storey = b.AnonymousMethodStorey;
3311 if (b_storey != null) {
3313 // Don't add storey cross reference for `this' when the storey ends up not
3314 // beeing attached to any parent
3316 if (b.ParametersBlock.StateMachine == null) {
3317 AnonymousMethodStorey s = null;
3318 for (Block ab = b.AnonymousMethodStorey.OriginalSourceBlock.Parent; ab != null; ab = ab.Parent) {
3319 s = ab.Explicit.AnonymousMethodStorey;
3324 // Needs to be in sync with AnonymousMethodBody::DoCreateMethodHost
3326 var parent = storey == null || storey.Kind == MemberKind.Struct ? null : storey;
3327 b.AnonymousMethodStorey.AddCapturedThisField (ec, parent);
3334 // Stop propagation inside same top block
3336 if (b.ParametersBlock == ParametersBlock.Original) {
3337 b_storey.AddParentStoreyReference (ec, storey);
3338 // b_storey.HoistedThis = storey.HoistedThis;
3342 b = pb = b.ParametersBlock;
3344 pb = b as ParametersBlock;
3347 if (pb != null && pb.StateMachine != null) {
3348 if (pb.StateMachine == storey)
3352 // If we are state machine with no parent. We can hook into parent without additional
3353 // reference and capture this directly
3355 ExplicitBlock parent_storey_block = pb;
3356 while (parent_storey_block.Parent != null) {
3357 parent_storey_block = parent_storey_block.Parent.Explicit;
3358 if (parent_storey_block.AnonymousMethodStorey != null) {
3363 if (parent_storey_block.AnonymousMethodStorey == null) {
3364 if (pb.StateMachine.HoistedThis == null) {
3365 pb.StateMachine.AddCapturedThisField (ec, null);
3366 b.HasCapturedThis = true;
3372 var parent_this_block = pb;
3373 while (parent_this_block.Parent != null) {
3374 parent_this_block = parent_this_block.Parent.ParametersBlock;
3375 if (parent_this_block.StateMachine != null && parent_this_block.StateMachine.HoistedThis != null) {
3381 // Add reference to closest storey which holds captured this
3383 pb.StateMachine.AddParentStoreyReference (ec, parent_this_block.StateMachine ?? storey);
3387 // Add parent storey reference only when this is not captured directly
3389 if (b_storey != null) {
3390 b_storey.AddParentStoreyReference (ec, storey);
3391 b_storey.HoistedThis = storey.HoistedThis;
3398 var ref_blocks = storey.ReferencesFromChildrenBlock;
3399 if (ref_blocks != null) {
3400 foreach (ExplicitBlock ref_block in ref_blocks) {
3401 for (ExplicitBlock b = ref_block; b.AnonymousMethodStorey != storey; b = b.Parent.Explicit) {
3402 if (b.AnonymousMethodStorey != null) {
3403 b.AnonymousMethodStorey.AddParentStoreyReference (ec, storey);
3406 // Stop propagation inside same top block
3408 if (b.ParametersBlock == ParametersBlock.Original)
3411 b = b.ParametersBlock;
3414 var pb = b as ParametersBlock;
3415 if (pb != null && pb.StateMachine != null) {
3416 if (pb.StateMachine == storey)
3419 pb.StateMachine.AddParentStoreyReference (ec, storey);
3422 b.HasCapturedVariable = true;
3428 storey.PrepareEmit ();
3429 storey.Parent.PartialContainer.AddCompilerGeneratedClass (storey);
3432 public void RegisterAsyncAwait ()
3435 while ((block.flags & Flags.AwaitBlock) == 0) {
3436 block.flags |= Flags.AwaitBlock;
3438 if (block is ParametersBlock)
3441 block = block.Parent.Explicit;
3445 public void RegisterIteratorYield ()
3447 ParametersBlock.TopBlock.IsIterator = true;
3450 while ((block.flags & Flags.YieldBlock) == 0) {
3451 block.flags |= Flags.YieldBlock;
3453 if (block.Parent == null)
3456 block = block.Parent.Explicit;
3460 public void SetCatchBlock ()
3462 flags |= Flags.CatchBlock;
3465 public void SetFinallyBlock ()
3467 flags |= Flags.FinallyBlock;
3470 public void WrapIntoDestructor (TryFinally tf, ExplicitBlock tryBlock)
3472 tryBlock.statements = statements;
3473 statements = new List<Statement> (1);
3474 statements.Add (tf);
3479 // ParametersBlock was introduced to support anonymous methods
3480 // and lambda expressions
3482 public class ParametersBlock : ExplicitBlock
3484 public class ParameterInfo : INamedBlockVariable
3486 readonly ParametersBlock block;
3488 public VariableInfo VariableInfo;
3491 public ParameterInfo (ParametersBlock block, int index)
3499 public ParametersBlock Block {
3505 Block INamedBlockVariable.Block {
3511 public bool IsDeclared {
3517 public bool IsParameter {
3523 public bool IsLocked {
3532 public Location Location {
3534 return Parameter.Location;
3538 public Parameter Parameter {
3540 return block.Parameters [index];
3544 public TypeSpec ParameterType {
3546 return Parameter.Type;
3552 public Expression CreateReferenceExpression (ResolveContext rc, Location loc)
3554 return new ParameterReference (this, loc);
3559 // Block is converted into an expression
3561 sealed class BlockScopeExpression : Expression
3564 readonly ParametersBlock block;
3566 public BlockScopeExpression (Expression child, ParametersBlock block)
3572 public override bool ContainsEmitWithAwait ()
3574 return child.ContainsEmitWithAwait ();
3577 public override Expression CreateExpressionTree (ResolveContext ec)
3579 throw new NotSupportedException ();
3582 protected override Expression DoResolve (ResolveContext ec)
3587 child = child.Resolve (ec);
3591 eclass = child.eclass;
3596 public override void Emit (EmitContext ec)
3598 block.EmitScopeInitializers (ec);
3603 protected ParametersCompiled parameters;
3604 protected ParameterInfo[] parameter_info;
3605 protected bool resolved;
3606 protected ToplevelBlock top_block;
3607 protected StateMachine state_machine;
3608 protected Dictionary<string, object> labels;
3610 public ParametersBlock (Block parent, ParametersCompiled parameters, Location start, Flags flags = 0)
3611 : base (parent, 0, start, start)
3613 if (parameters == null)
3614 throw new ArgumentNullException ("parameters");
3616 this.parameters = parameters;
3617 ParametersBlock = this;
3619 this.flags |= flags | (parent.ParametersBlock.flags & (Flags.YieldBlock | Flags.AwaitBlock));
3621 this.top_block = parent.ParametersBlock.top_block;
3622 ProcessParameters ();
3625 protected ParametersBlock (ParametersCompiled parameters, Location start)
3626 : base (null, 0, start, start)
3628 if (parameters == null)
3629 throw new ArgumentNullException ("parameters");
3631 this.parameters = parameters;
3632 ParametersBlock = this;
3636 // It's supposed to be used by method body implementation of anonymous methods
3638 protected ParametersBlock (ParametersBlock source, ParametersCompiled parameters)
3639 : base (null, 0, source.StartLocation, source.EndLocation)
3641 this.parameters = parameters;
3642 this.statements = source.statements;
3643 this.scope_initializers = source.scope_initializers;
3645 this.resolved = true;
3646 this.reachable = source.reachable;
3647 this.am_storey = source.am_storey;
3648 this.state_machine = source.state_machine;
3649 this.flags = source.flags & Flags.ReachableEnd;
3651 ParametersBlock = this;
3654 // Overwrite original for comparison purposes when linking cross references
3655 // between anonymous methods
3657 Original = source.Original;
3662 public bool IsAsync {
3664 return (flags & Flags.HasAsyncModifier) != 0;
3667 flags = value ? flags | Flags.HasAsyncModifier : flags & ~Flags.HasAsyncModifier;
3672 // Block has been converted to expression tree
3674 public bool IsExpressionTree {
3676 return (flags & Flags.IsExpressionTree) != 0;
3681 // The parameters for the block.
3683 public ParametersCompiled Parameters {
3689 public StateMachine StateMachine {
3691 return state_machine;
3695 public ToplevelBlock TopBlock {
3704 public bool Resolved {
3706 return (flags & Flags.Resolved) != 0;
3710 public int TemporaryLocalsCount { get; set; }
3715 // Checks whether all `out' parameters have been assigned.
3717 public void CheckControlExit (FlowAnalysisContext fc)
3719 CheckControlExit (fc, fc.DefiniteAssignment);
3722 public virtual void CheckControlExit (FlowAnalysisContext fc, DefiniteAssignmentBitSet dat)
3724 if (parameter_info == null)
3727 foreach (var p in parameter_info) {
3728 if (p.VariableInfo == null)
3731 if (p.VariableInfo.IsAssigned (dat))
3734 fc.Report.Error (177, p.Location,
3735 "The out parameter `{0}' must be assigned to before control leaves the current method",
3740 protected override void CloneTo (CloneContext clonectx, Statement t)
3742 base.CloneTo (clonectx, t);
3744 var target = (ParametersBlock) t;
3747 // Clone label statements as well as they contain block reference
3751 if (pb.labels != null) {
3752 target.labels = new Dictionary<string, object> ();
3754 foreach (var entry in pb.labels) {
3755 var list = entry.Value as List<LabeledStatement>;
3758 var list_clone = new List<LabeledStatement> ();
3759 foreach (var lentry in list) {
3760 list_clone.Add (RemapLabeledStatement (lentry, clonectx.RemapBlockCopy (lentry.Block)));
3763 target.labels.Add (entry.Key, list_clone);
3765 var labeled = (LabeledStatement) entry.Value;
3766 target.labels.Add (entry.Key, RemapLabeledStatement (labeled, clonectx.RemapBlockCopy (labeled.Block)));
3773 if (pb.Parent == null)
3776 pb = pb.Parent.ParametersBlock;
3780 public override Expression CreateExpressionTree (ResolveContext ec)
3782 if (statements.Count == 1) {
3783 Expression expr = statements[0].CreateExpressionTree (ec);
3784 if (scope_initializers != null)
3785 expr = new BlockScopeExpression (expr, this);
3790 return base.CreateExpressionTree (ec);
3793 public override void Emit (EmitContext ec)
3795 if (state_machine != null && state_machine.OriginalSourceBlock != this) {
3796 DefineStoreyContainer (ec, state_machine);
3797 state_machine.EmitStoreyInstantiation (ec, this);
3803 public void EmitEmbedded (EmitContext ec)
3805 if (state_machine != null && state_machine.OriginalSourceBlock != this) {
3806 DefineStoreyContainer (ec, state_machine);
3807 state_machine.EmitStoreyInstantiation (ec, this);
3813 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
3815 var res = base.DoFlowAnalysis (fc);
3817 if (HasReachableClosingBrace)
3818 CheckControlExit (fc);
3823 public LabeledStatement GetLabel (string name, Block block)
3826 // Cloned parameters blocks can have their own cloned version of top-level labels
3828 if (labels == null) {
3830 return Parent.ParametersBlock.GetLabel (name, block);
3836 if (!labels.TryGetValue (name, out value)) {
3840 var label = value as LabeledStatement;
3842 if (label != null) {
3843 if (IsLabelVisible (label, b))
3847 List<LabeledStatement> list = (List<LabeledStatement>) value;
3848 for (int i = 0; i < list.Count; ++i) {
3850 if (IsLabelVisible (label, b))
3858 static bool IsLabelVisible (LabeledStatement label, Block b)
3861 if (label.Block == b)
3864 } while (b != null);
3869 public ParameterInfo GetParameterInfo (Parameter p)
3871 for (int i = 0; i < parameters.Count; ++i) {
3872 if (parameters[i] == p)
3873 return parameter_info[i];
3876 throw new ArgumentException ("Invalid parameter");
3879 public ParameterReference GetParameterReference (int index, Location loc)
3881 return new ParameterReference (parameter_info[index], loc);
3884 public Statement PerformClone ()
3886 CloneContext clonectx = new CloneContext ();
3887 return Clone (clonectx);
3890 protected void ProcessParameters ()
3892 if (parameters.Count == 0)
3895 parameter_info = new ParameterInfo[parameters.Count];
3896 for (int i = 0; i < parameter_info.Length; ++i) {
3897 var p = parameters.FixedParameters[i];
3901 // TODO: Should use Parameter only and more block there
3902 parameter_info[i] = new ParameterInfo (this, i);
3904 AddLocalName (p.Name, parameter_info[i]);
3908 LabeledStatement RemapLabeledStatement (LabeledStatement stmt, Block dst)
3910 var src = stmt.Block;
3913 // Cannot remap label block if the label was not yet cloned which
3914 // can happen in case of anonymous method inside anoynymous method
3915 // with a label. But in this case we don't care because goto cannot
3916 // jump of out anonymous method
3918 if (src.ParametersBlock != this)
3921 var src_stmts = src.Statements;
3922 for (int i = 0; i < src_stmts.Count; ++i) {
3923 if (src_stmts[i] == stmt)
3924 return (LabeledStatement) dst.Statements[i];
3927 throw new InternalErrorException ("Should never be reached");
3930 public override bool Resolve (BlockContext bc)
3932 // TODO: if ((flags & Flags.Resolved) != 0)
3939 if (bc.HasSet (ResolveContext.Options.ExpressionTreeConversion))
3940 flags |= Flags.IsExpressionTree;
3943 PrepareAssignmentAnalysis (bc);
3945 if (!base.Resolve (bc))
3948 } catch (Exception e) {
3949 if (e is CompletionResult || bc.Report.IsDisabled || e is FatalException || bc.Report.Printer is NullReportPrinter || bc.Module.Compiler.Settings.BreakOnInternalError)
3952 if (bc.CurrentBlock != null) {
3953 bc.Report.Error (584, bc.CurrentBlock.StartLocation, "Internal compiler error: {0}", e.Message);
3955 bc.Report.Error (587, "Internal compiler error: {0}", e.Message);
3960 // If an asynchronous body of F is either an expression classified as nothing, or a
3961 // statement block where no return statements have expressions, the inferred return type is Task
3964 var am = bc.CurrentAnonymousMethod as AnonymousMethodBody;
3965 if (am != null && am.ReturnTypeInference != null && !am.ReturnTypeInference.HasBounds (0)) {
3966 am.ReturnTypeInference = null;
3967 am.ReturnType = bc.Module.PredefinedTypes.Task.TypeSpec;
3975 void PrepareAssignmentAnalysis (BlockContext bc)
3977 for (int i = 0; i < parameters.Count; ++i) {
3978 var par = parameters.FixedParameters[i];
3980 if ((par.ModFlags & Parameter.Modifier.OUT) == 0)
3983 parameter_info [i].VariableInfo = VariableInfo.Create (bc, (Parameter) par);
3987 public ToplevelBlock ConvertToIterator (IMethodData method, TypeDefinition host, TypeSpec iterator_type, bool is_enumerable)
3989 var iterator = new Iterator (this, method, host, iterator_type, is_enumerable);
3990 var stateMachine = new IteratorStorey (iterator);
3992 state_machine = stateMachine;
3993 iterator.SetStateMachine (stateMachine);
3995 var tlb = new ToplevelBlock (host.Compiler, Parameters, Location.Null, Flags.CompilerGenerated);
3996 tlb.Original = this;
3997 tlb.state_machine = stateMachine;
3998 tlb.AddStatement (new Return (iterator, iterator.Location));
4002 public ParametersBlock ConvertToAsyncTask (IMemberContext context, TypeDefinition host, ParametersCompiled parameters, TypeSpec returnType, TypeSpec delegateType, Location loc)
4004 for (int i = 0; i < parameters.Count; i++) {
4005 Parameter p = parameters[i];
4006 Parameter.Modifier mod = p.ModFlags;
4007 if ((mod & Parameter.Modifier.RefOutMask) != 0) {
4008 host.Compiler.Report.Error (1988, p.Location,
4009 "Async methods cannot have ref or out parameters");
4013 if (p is ArglistParameter) {
4014 host.Compiler.Report.Error (4006, p.Location,
4015 "__arglist is not allowed in parameter list of async methods");
4019 if (parameters.Types[i].IsPointer) {
4020 host.Compiler.Report.Error (4005, p.Location,
4021 "Async methods cannot have unsafe parameters");
4027 host.Compiler.Report.Warning (1998, 1, loc,
4028 "Async block lacks `await' operator and will run synchronously");
4031 var block_type = host.Module.Compiler.BuiltinTypes.Void;
4032 var initializer = new AsyncInitializer (this, host, block_type);
4033 initializer.Type = block_type;
4034 initializer.DelegateType = delegateType;
4036 var stateMachine = new AsyncTaskStorey (this, context, initializer, returnType);
4038 state_machine = stateMachine;
4039 initializer.SetStateMachine (stateMachine);
4041 const Flags flags = Flags.CompilerGenerated;
4043 var b = this is ToplevelBlock ?
4044 new ToplevelBlock (host.Compiler, Parameters, Location.Null, flags) :
4045 new ParametersBlock (Parent, parameters, Location.Null, flags | Flags.HasAsyncModifier);
4048 b.state_machine = stateMachine;
4049 b.AddStatement (new AsyncInitializerStatement (initializer));
4057 public class ToplevelBlock : ParametersBlock
4059 LocalVariable this_variable;
4060 CompilerContext compiler;
4061 Dictionary<string, object> names;
4063 List<ExplicitBlock> this_references;
4065 public ToplevelBlock (CompilerContext ctx, Location loc)
4066 : this (ctx, ParametersCompiled.EmptyReadOnlyParameters, loc)
4070 public ToplevelBlock (CompilerContext ctx, ParametersCompiled parameters, Location start, Flags flags = 0)
4071 : base (parameters, start)
4073 this.compiler = ctx;
4077 ProcessParameters ();
4081 // Recreates a top level block from parameters block. Used for
4082 // compiler generated methods where the original block comes from
4083 // explicit child block. This works for already resolved blocks
4084 // only to ensure we resolve them in the correct flow order
4086 public ToplevelBlock (ParametersBlock source, ParametersCompiled parameters)
4087 : base (source, parameters)
4089 this.compiler = source.TopBlock.compiler;
4093 public bool IsIterator {
4095 return (flags & Flags.Iterator) != 0;
4098 flags = value ? flags | Flags.Iterator : flags & ~Flags.Iterator;
4102 public Report Report {
4104 return compiler.Report;
4109 // Used by anonymous blocks to track references of `this' variable
4111 public List<ExplicitBlock> ThisReferencesFromChildrenBlock {
4113 return this_references;
4118 // Returns the "this" instance variable of this block.
4119 // See AddThisVariable() for more information.
4121 public LocalVariable ThisVariable {
4123 return this_variable;
4127 public void AddLocalName (string name, INamedBlockVariable li, bool ignoreChildrenBlocks)
4130 names = new Dictionary<string, object> ();
4133 if (!names.TryGetValue (name, out value)) {
4134 names.Add (name, li);
4138 INamedBlockVariable existing = value as INamedBlockVariable;
4139 List<INamedBlockVariable> existing_list;
4140 if (existing != null) {
4141 existing_list = new List<INamedBlockVariable> ();
4142 existing_list.Add (existing);
4143 names[name] = existing_list;
4145 existing_list = (List<INamedBlockVariable>) value;
4149 // A collision checking between local names
4151 var variable_block = li.Block.Explicit;
4152 for (int i = 0; i < existing_list.Count; ++i) {
4153 existing = existing_list[i];
4154 Block b = existing.Block.Explicit;
4156 // Collision at same level
4157 if (variable_block == b) {
4158 li.Block.Error_AlreadyDeclared (name, li);
4162 // Collision with parent
4163 Block parent = variable_block;
4164 while ((parent = parent.Parent) != null) {
4166 li.Block.Error_AlreadyDeclared (name, li, "parent or current");
4167 i = existing_list.Count;
4172 if (!ignoreChildrenBlocks && variable_block.Parent != b.Parent) {
4173 // Collision with children
4174 while ((b = b.Parent) != null) {
4175 if (variable_block == b) {
4176 li.Block.Error_AlreadyDeclared (name, li, "child");
4177 i = existing_list.Count;
4184 existing_list.Add (li);
4187 public void AddLabel (string name, LabeledStatement label)
4190 labels = new Dictionary<string, object> ();
4193 if (!labels.TryGetValue (name, out value)) {
4194 labels.Add (name, label);
4198 LabeledStatement existing = value as LabeledStatement;
4199 List<LabeledStatement> existing_list;
4200 if (existing != null) {
4201 existing_list = new List<LabeledStatement> ();
4202 existing_list.Add (existing);
4203 labels[name] = existing_list;
4205 existing_list = (List<LabeledStatement>) value;
4209 // A collision checking between labels
4211 for (int i = 0; i < existing_list.Count; ++i) {
4212 existing = existing_list[i];
4213 Block b = existing.Block;
4215 // Collision at same level
4216 if (label.Block == b) {
4217 Report.SymbolRelatedToPreviousError (existing.loc, name);
4218 Report.Error (140, label.loc, "The label `{0}' is a duplicate", name);
4222 // Collision with parent
4224 while ((b = b.Parent) != null) {
4225 if (existing.Block == b) {
4226 Report.Error (158, label.loc,
4227 "The label `{0}' shadows another label by the same name in a contained scope", name);
4228 i = existing_list.Count;
4233 // Collision with with children
4235 while ((b = b.Parent) != null) {
4236 if (label.Block == b) {
4237 Report.Error (158, label.loc,
4238 "The label `{0}' shadows another label by the same name in a contained scope", name);
4239 i = existing_list.Count;
4245 existing_list.Add (label);
4248 public void AddThisReferenceFromChildrenBlock (ExplicitBlock block)
4250 if (this_references == null)
4251 this_references = new List<ExplicitBlock> ();
4253 if (!this_references.Contains (block))
4254 this_references.Add (block);
4257 public void RemoveThisReferenceFromChildrenBlock (ExplicitBlock block)
4259 this_references.Remove (block);
4263 // Creates an arguments set from all parameters, useful for method proxy calls
4265 public Arguments GetAllParametersArguments ()
4267 int count = parameters.Count;
4268 Arguments args = new Arguments (count);
4269 for (int i = 0; i < count; ++i) {
4270 var pi = parameter_info[i];
4271 var arg_expr = GetParameterReference (i, pi.Location);
4273 Argument.AType atype_modifier;
4274 switch (pi.Parameter.ParameterModifier & Parameter.Modifier.RefOutMask) {
4275 case Parameter.Modifier.REF:
4276 atype_modifier = Argument.AType.Ref;
4278 case Parameter.Modifier.OUT:
4279 atype_modifier = Argument.AType.Out;
4286 args.Add (new Argument (arg_expr, atype_modifier));
4293 // Lookup inside a block, the returned value can represent 3 states
4295 // true+variable: A local name was found and it's valid
4296 // false+variable: A local name was found in a child block only
4297 // false+null: No local name was found
4299 public bool GetLocalName (string name, Block block, ref INamedBlockVariable variable)
4305 if (!names.TryGetValue (name, out value))
4308 variable = value as INamedBlockVariable;
4310 if (variable != null) {
4312 if (variable.Block == b.Original)
4316 } while (b != null);
4324 } while (b != null);
4326 List<INamedBlockVariable> list = (List<INamedBlockVariable>) value;
4327 for (int i = 0; i < list.Count; ++i) {
4330 if (variable.Block == b.Original)
4334 } while (b != null);
4342 } while (b != null);
4352 public void IncludeBlock (ParametersBlock pb, ToplevelBlock block)
4354 if (block.names != null) {
4355 foreach (var n in block.names) {
4356 var variable = n.Value as INamedBlockVariable;
4357 if (variable != null) {
4358 if (variable.Block.ParametersBlock == pb)
4359 AddLocalName (n.Key, variable, false);
4363 foreach (var v in (List<INamedBlockVariable>) n.Value)
4364 if (v.Block.ParametersBlock == pb)
4365 AddLocalName (n.Key, v, false);
4371 // This is used by non-static `struct' constructors which do not have an
4372 // initializer - in this case, the constructor must initialize all of the
4373 // struct's fields. To do this, we add a "this" variable and use the flow
4374 // analysis code to ensure that it's been fully initialized before control
4375 // leaves the constructor.
4377 public void AddThisVariable (BlockContext bc)
4379 if (this_variable != null)
4380 throw new InternalErrorException (StartLocation.ToString ());
4382 this_variable = new LocalVariable (this, "this", LocalVariable.Flags.IsThis | LocalVariable.Flags.Used, StartLocation);
4383 this_variable.Type = bc.CurrentType;
4384 this_variable.PrepareAssignmentAnalysis (bc);
4387 public override void CheckControlExit (FlowAnalysisContext fc, DefiniteAssignmentBitSet dat)
4390 // If we're a non-static struct constructor which doesn't have an
4391 // initializer, then we must initialize all of the struct's fields.
4393 if (this_variable != null)
4394 this_variable.IsThisAssigned (fc, this);
4396 base.CheckControlExit (fc, dat);
4399 public override void Emit (EmitContext ec)
4401 if (Report.Errors > 0)
4405 if (IsCompilerGenerated) {
4406 using (ec.With (BuilderContext.Options.OmitDebugInfo, true)) {
4414 // If `HasReturnLabel' is set, then we already emitted a
4415 // jump to the end of the method, so we must emit a `ret'
4418 // Unfortunately, System.Reflection.Emit automatically emits
4419 // a leave to the end of a finally block. This is a problem
4420 // if no code is following the try/finally block since we may
4421 // jump to a point after the end of the method.
4422 // As a workaround, we're always creating a return label in
4425 if (ec.HasReturnLabel || HasReachableClosingBrace) {
4426 if (ec.HasReturnLabel)
4427 ec.MarkLabel (ec.ReturnLabel);
4429 if (ec.EmitAccurateDebugInfo && !IsCompilerGenerated)
4430 ec.Mark (EndLocation);
4432 if (ec.ReturnType.Kind != MemberKind.Void)
4433 ec.Emit (OpCodes.Ldloc, ec.TemporaryReturn ());
4435 ec.Emit (OpCodes.Ret);
4438 } catch (Exception e) {
4439 throw new InternalErrorException (e, StartLocation);
4443 public bool Resolve (BlockContext bc, IMethodData md)
4448 var errors = bc.Report.Errors;
4452 if (bc.Report.Errors > errors)
4455 MarkReachable (new Reachability ());
4457 if (HasReachableClosingBrace && bc.ReturnType.Kind != MemberKind.Void) {
4458 // TODO: var md = bc.CurrentMemberDefinition;
4459 bc.Report.Error (161, md.Location, "`{0}': not all code paths return a value", md.GetSignatureForError ());
4462 if ((flags & Flags.NoFlowAnalysis) != 0)
4465 var fc = new FlowAnalysisContext (bc.Module.Compiler, this, bc.AssignmentInfoOffset);
4468 } catch (Exception e) {
4469 throw new InternalErrorException (e, StartLocation);
4476 public class SwitchLabel : Statement
4484 // if expr == null, then it is the default case.
4486 public SwitchLabel (Expression expr, Location l)
4492 public bool IsDefault {
4494 return label == null;
4498 public Expression Label {
4504 public Location Location {
4510 public Constant Converted {
4519 public bool PatternMatching { get; set; }
4521 public bool SectionStart { get; set; }
4523 public Label GetILLabel (EmitContext ec)
4525 if (il_label == null){
4526 il_label = ec.DefineLabel ();
4529 return il_label.Value;
4532 protected override void DoEmit (EmitContext ec)
4534 ec.MarkLabel (GetILLabel (ec));
4537 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
4542 fc.BranchDefiniteAssignment (fc.SwitchInitialDefinitiveAssignment);
4546 public override bool Resolve (BlockContext bc)
4548 if (ResolveAndReduce (bc))
4549 bc.Switch.RegisterLabel (bc, this);
4555 // Resolves the expression, reduces it to a literal if possible
4556 // and then converts it to the requested type.
4558 bool ResolveAndReduce (BlockContext bc)
4563 var switch_statement = bc.Switch;
4565 if (PatternMatching) {
4566 label = new Is (switch_statement.ExpressionValue, label, loc).Resolve (bc);
4567 return label != null;
4570 var c = label.ResolveLabelConstant (bc);
4574 if (switch_statement.IsNullable && c is NullLiteral) {
4579 if (switch_statement.IsPatternMatching) {
4580 label = new Is (switch_statement.ExpressionValue, label, loc).Resolve (bc);
4584 converted = c.ImplicitConversionRequired (bc, switch_statement.SwitchType);
4585 return converted != null;
4588 public void Error_AlreadyOccurs (ResolveContext ec, SwitchLabel collision_with)
4590 ec.Report.SymbolRelatedToPreviousError (collision_with.loc, null);
4591 ec.Report.Error (152, loc, "The label `{0}' already occurs in this switch statement", GetSignatureForError ());
4594 protected override void CloneTo (CloneContext clonectx, Statement target)
4596 var t = (SwitchLabel) target;
4598 t.label = label.Clone (clonectx);
4601 public override object Accept (StructuralVisitor visitor)
4603 return visitor.Visit (this);
4606 public string GetSignatureForError ()
4609 if (converted == null)
4612 label = converted.GetValueAsLiteral ();
4614 return string.Format ("case {0}:", label);
4618 public class Switch : LoopStatement
4620 // structure used to hold blocks of keys while calculating table switch
4621 sealed class LabelsRange : IComparable<LabelsRange>
4623 public readonly long min;
4625 public readonly List<long> label_values;
4627 public LabelsRange (long value)
4630 label_values = new List<long> ();
4631 label_values.Add (value);
4634 public LabelsRange (long min, long max, ICollection<long> values)
4638 this.label_values = new List<long> (values);
4643 return max - min + 1;
4647 public bool AddValue (long value)
4649 var gap = value - min + 1;
4650 // Ensure the range has > 50% occupancy
4651 if (gap > 2 * (label_values.Count + 1) || gap <= 0)
4655 label_values.Add (value);
4659 public int CompareTo (LabelsRange other)
4661 int nLength = label_values.Count;
4662 int nLengthOther = other.label_values.Count;
4663 if (nLengthOther == nLength)
4664 return (int) (other.min - min);
4666 return nLength - nLengthOther;
4670 sealed class DispatchStatement : Statement
4672 readonly Switch body;
4674 public DispatchStatement (Switch body)
4679 protected override void CloneTo (CloneContext clonectx, Statement target)
4681 throw new NotImplementedException ();
4684 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
4689 protected override void DoEmit (EmitContext ec)
4691 body.EmitDispatch (ec);
4695 class MissingBreak : Statement
4697 readonly SwitchLabel label;
4699 public MissingBreak (SwitchLabel sl)
4705 public bool FallOut { get; set; }
4707 protected override void DoEmit (EmitContext ec)
4711 protected override void CloneTo (CloneContext clonectx, Statement target)
4715 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
4718 fc.Report.Error (8070, loc, "Control cannot fall out of switch statement through final case label `{0}'",
4719 label.GetSignatureForError ());
4721 fc.Report.Error (163, loc, "Control cannot fall through from one case label `{0}' to another",
4722 label.GetSignatureForError ());
4728 public Expression Expr;
4731 // Mapping of all labels to their SwitchLabels
4733 Dictionary<long, SwitchLabel> labels;
4734 Dictionary<string, SwitchLabel> string_labels;
4735 List<SwitchLabel> case_labels;
4737 List<Tuple<GotoCase, Constant>> goto_cases;
4738 List<DefiniteAssignmentBitSet> end_reachable_das;
4741 /// The governing switch type
4743 public TypeSpec SwitchType;
4745 Expression new_expr;
4747 SwitchLabel case_null;
4748 SwitchLabel case_default;
4750 Label defaultLabel, nullLabel;
4751 VariableReference value;
4752 ExpressionStatement string_dictionary;
4753 FieldExpr switch_cache_field;
4754 ExplicitBlock block;
4758 // Nullable Types support
4760 Nullable.Unwrap unwrap;
4762 public Switch (Expression e, ExplicitBlock block, Location l)
4770 public SwitchLabel ActiveLabel { get; set; }
4772 public ExplicitBlock Block {
4778 public SwitchLabel DefaultLabel {
4780 return case_default;
4784 public bool IsNullable {
4786 return unwrap != null;
4790 public bool IsPatternMatching {
4792 return new_expr == null && SwitchType != null;
4796 public List<SwitchLabel> RegisteredLabels {
4802 public VariableReference ExpressionValue {
4809 // Determines the governing type for a switch. The returned
4810 // expression might be the expression from the switch, or an
4811 // expression that includes any potential conversions to
4813 static Expression SwitchGoverningType (ResolveContext rc, Expression expr, bool unwrapExpr)
4815 switch (expr.Type.BuiltinType) {
4816 case BuiltinTypeSpec.Type.Byte:
4817 case BuiltinTypeSpec.Type.SByte:
4818 case BuiltinTypeSpec.Type.UShort:
4819 case BuiltinTypeSpec.Type.Short:
4820 case BuiltinTypeSpec.Type.UInt:
4821 case BuiltinTypeSpec.Type.Int:
4822 case BuiltinTypeSpec.Type.ULong:
4823 case BuiltinTypeSpec.Type.Long:
4824 case BuiltinTypeSpec.Type.Char:
4825 case BuiltinTypeSpec.Type.String:
4826 case BuiltinTypeSpec.Type.Bool:
4830 if (expr.Type.IsEnum)
4834 // Try to find a *user* defined implicit conversion.
4836 // If there is no implicit conversion, or if there are multiple
4837 // conversions, we have to report an error
4839 Expression converted = null;
4840 foreach (TypeSpec tt in rc.Module.PredefinedTypes.SwitchUserTypes) {
4842 if (!unwrapExpr && tt.IsNullableType && expr.Type.IsNullableType)
4845 var restr = Convert.UserConversionRestriction.ImplicitOnly |
4846 Convert.UserConversionRestriction.ProbingOnly;
4849 restr |= Convert.UserConversionRestriction.NullableSourceOnly;
4851 var e = Convert.UserDefinedConversion (rc, expr, tt, restr, Location.Null);
4856 // Ignore over-worked ImplicitUserConversions that do
4857 // an implicit conversion in addition to the user conversion.
4859 var uc = e as UserCast;
4863 if (converted != null){
4864 // rc.Report.ExtraInformation (loc, "(Ambiguous implicit user defined conversion in previous ");
4873 public static TypeSpec[] CreateSwitchUserTypes (ModuleContainer module, TypeSpec nullable)
4875 var types = module.Compiler.BuiltinTypes;
4877 // LAMESPEC: For some reason it does not contain bool which looks like csc bug
4878 TypeSpec[] stypes = new[] {
4891 if (nullable != null) {
4893 Array.Resize (ref stypes, stypes.Length + 9);
4895 for (int i = 0; i < 9; ++i) {
4896 stypes [10 + i] = nullable.MakeGenericType (module, new [] { stypes [i] });
4903 public void RegisterLabel (BlockContext rc, SwitchLabel sl)
4905 case_labels.Add (sl);
4908 if (case_default != null) {
4909 sl.Error_AlreadyOccurs (rc, case_default);
4917 if (sl.Converted == null)
4921 if (string_labels != null) {
4922 string string_value = sl.Converted.GetValue () as string;
4923 if (string_value == null)
4926 string_labels.Add (string_value, sl);
4928 if (sl.Converted.IsNull) {
4931 labels.Add (sl.Converted.GetValueAsLong (), sl);
4934 } catch (ArgumentException) {
4935 if (string_labels != null)
4936 sl.Error_AlreadyOccurs (rc, string_labels[(string) sl.Converted.GetValue ()]);
4938 sl.Error_AlreadyOccurs (rc, labels[sl.Converted.GetValueAsLong ()]);
4943 // This method emits code for a lookup-based switch statement (non-string)
4944 // Basically it groups the cases into blocks that are at least half full,
4945 // and then spits out individual lookup opcodes for each block.
4946 // It emits the longest blocks first, and short blocks are just
4947 // handled with direct compares.
4949 void EmitTableSwitch (EmitContext ec, Expression val)
4951 if (labels != null && labels.Count > 0) {
4952 List<LabelsRange> ranges;
4953 if (string_labels != null) {
4954 // We have done all hard work for string already
4955 // setup single range only
4956 ranges = new List<LabelsRange> (1);
4957 ranges.Add (new LabelsRange (0, labels.Count - 1, labels.Keys));
4959 var element_keys = new long[labels.Count];
4960 labels.Keys.CopyTo (element_keys, 0);
4961 Array.Sort (element_keys);
4964 // Build possible ranges of switch labes to reduce number
4967 ranges = new List<LabelsRange> (element_keys.Length);
4968 var range = new LabelsRange (element_keys[0]);
4970 for (int i = 1; i < element_keys.Length; ++i) {
4971 var l = element_keys[i];
4972 if (range.AddValue (l))
4975 range = new LabelsRange (l);
4979 // sort the blocks so we can tackle the largest ones first
4983 Label lbl_default = defaultLabel;
4984 TypeSpec compare_type = SwitchType.IsEnum ? EnumSpec.GetUnderlyingType (SwitchType) : SwitchType;
4986 for (int range_index = ranges.Count - 1; range_index >= 0; --range_index) {
4987 LabelsRange kb = ranges[range_index];
4988 lbl_default = (range_index == 0) ? defaultLabel : ec.DefineLabel ();
4990 // Optimize small ranges using simple equality check
4991 if (kb.Range <= 2) {
4992 foreach (var key in kb.label_values) {
4993 SwitchLabel sl = labels[key];
4994 if (sl == case_default || sl == case_null)
4997 if (sl.Converted.IsZeroInteger) {
4998 val.EmitBranchable (ec, sl.GetILLabel (ec), false);
5001 sl.Converted.Emit (ec);
5002 ec.Emit (OpCodes.Beq, sl.GetILLabel (ec));
5006 // TODO: if all the keys in the block are the same and there are
5007 // no gaps/defaults then just use a range-check.
5008 if (compare_type.BuiltinType == BuiltinTypeSpec.Type.Long || compare_type.BuiltinType == BuiltinTypeSpec.Type.ULong) {
5009 // TODO: optimize constant/I4 cases
5011 // check block range (could be > 2^31)
5013 ec.EmitLong (kb.min);
5014 ec.Emit (OpCodes.Blt, lbl_default);
5017 ec.EmitLong (kb.max);
5018 ec.Emit (OpCodes.Bgt, lbl_default);
5023 ec.EmitLong (kb.min);
5024 ec.Emit (OpCodes.Sub);
5027 ec.Emit (OpCodes.Conv_I4); // assumes < 2^31 labels!
5031 int first = (int) kb.min;
5034 ec.Emit (OpCodes.Sub);
5035 } else if (first < 0) {
5036 ec.EmitInt (-first);
5037 ec.Emit (OpCodes.Add);
5041 // first, build the list of labels for the switch
5043 long cJumps = kb.Range;
5044 Label[] switch_labels = new Label[cJumps];
5045 for (int iJump = 0; iJump < cJumps; iJump++) {
5046 var key = kb.label_values[iKey];
5047 if (key == kb.min + iJump) {
5048 switch_labels[iJump] = labels[key].GetILLabel (ec);
5051 switch_labels[iJump] = lbl_default;
5055 // emit the switch opcode
5056 ec.Emit (OpCodes.Switch, switch_labels);
5059 // mark the default for this block
5060 if (range_index != 0)
5061 ec.MarkLabel (lbl_default);
5064 // the last default just goes to the end
5065 if (ranges.Count > 0)
5066 ec.Emit (OpCodes.Br, lbl_default);
5070 public SwitchLabel FindLabel (Constant value)
5072 SwitchLabel sl = null;
5074 if (string_labels != null) {
5075 string s = value.GetValue () as string;
5077 if (case_null != null)
5079 else if (case_default != null)
5082 string_labels.TryGetValue (s, out sl);
5085 if (value is NullLiteral) {
5088 labels.TryGetValue (value.GetValueAsLong (), out sl);
5092 if (sl == null || sl.SectionStart)
5096 // Always return section start, it simplifies handling of switch labels
5098 for (int idx = case_labels.IndexOf (sl); ; --idx) {
5099 var cs = case_labels [idx];
5100 if (cs.SectionStart)
5105 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
5107 Expr.FlowAnalysis (fc);
5109 var prev_switch = fc.SwitchInitialDefinitiveAssignment;
5110 var InitialDefinitiveAssignment = fc.DefiniteAssignment;
5111 fc.SwitchInitialDefinitiveAssignment = InitialDefinitiveAssignment;
5113 block.FlowAnalysis (fc);
5115 fc.SwitchInitialDefinitiveAssignment = prev_switch;
5117 if (end_reachable_das != null) {
5118 var sections_das = DefiniteAssignmentBitSet.And (end_reachable_das);
5119 InitialDefinitiveAssignment |= sections_das;
5120 end_reachable_das = null;
5123 fc.DefiniteAssignment = InitialDefinitiveAssignment;
5125 return case_default != null && !end_reachable;
5128 public override bool Resolve (BlockContext ec)
5130 Expr = Expr.Resolve (ec);
5135 // LAMESPEC: User conversion from non-nullable governing type has a priority
5137 new_expr = SwitchGoverningType (ec, Expr, false);
5139 if (new_expr == null) {
5140 if (Expr.Type.IsNullableType) {
5141 unwrap = Nullable.Unwrap.Create (Expr, false);
5146 // Unwrap + user conversion using non-nullable type is not allowed but user operator
5147 // involving nullable Expr and nullable governing type is
5149 new_expr = SwitchGoverningType (ec, unwrap, true);
5153 Expression switch_expr;
5154 if (new_expr == null) {
5155 if (ec.Module.Compiler.Settings.Version != LanguageVersion.Experimental) {
5156 if (Expr.Type != InternalType.ErrorType) {
5157 ec.Report.Error (151, loc,
5158 "A switch expression of type `{0}' cannot be converted to an integral type, bool, char, string, enum or nullable type",
5159 Expr.Type.GetSignatureForError ());
5166 SwitchType = Expr.Type;
5168 switch_expr = new_expr;
5169 SwitchType = new_expr.Type;
5170 if (SwitchType.IsNullableType) {
5171 new_expr = unwrap = Nullable.Unwrap.Create (new_expr, true);
5172 SwitchType = Nullable.NullableInfo.GetUnderlyingType (SwitchType);
5175 if (SwitchType.BuiltinType == BuiltinTypeSpec.Type.Bool && ec.Module.Compiler.Settings.Version == LanguageVersion.ISO_1) {
5176 ec.Report.FeatureIsNotAvailable (ec.Module.Compiler, loc, "switch expression of boolean type");
5180 if (block.Statements.Count == 0)
5183 if (SwitchType.BuiltinType == BuiltinTypeSpec.Type.String) {
5184 string_labels = new Dictionary<string, SwitchLabel> ();
5186 labels = new Dictionary<long, SwitchLabel> ();
5190 var constant = switch_expr as Constant;
5193 // Don't need extra variable for constant switch or switch with
5194 // only default case
5196 if (constant == null) {
5198 // Store switch expression for comparison purposes
5200 value = switch_expr as VariableReference;
5201 if (value == null && !HasOnlyDefaultSection ()) {
5202 var current_block = ec.CurrentBlock;
5203 ec.CurrentBlock = Block;
5204 // Create temporary variable inside switch scope
5205 value = TemporaryVariableReference.Create (SwitchType, ec.CurrentBlock, loc);
5207 ec.CurrentBlock = current_block;
5211 case_labels = new List<SwitchLabel> ();
5213 Switch old_switch = ec.Switch;
5215 var parent_los = ec.EnclosingLoopOrSwitch;
5216 ec.EnclosingLoopOrSwitch = this;
5218 var ok = Statement.Resolve (ec);
5220 ec.EnclosingLoopOrSwitch = parent_los;
5221 ec.Switch = old_switch;
5224 // Check if all goto cases are valid. Needs to be done after switch
5225 // is resolved because goto can jump forward in the scope.
5227 if (goto_cases != null) {
5228 foreach (var gc in goto_cases) {
5229 if (gc.Item1 == null) {
5230 if (DefaultLabel == null) {
5231 Goto.Error_UnknownLabel (ec, "default", loc);
5237 var sl = FindLabel (gc.Item2);
5239 Goto.Error_UnknownLabel (ec, "case " + gc.Item2.GetValueAsLiteral (), loc);
5241 gc.Item1.Label = sl;
5249 if (constant == null && SwitchType.BuiltinType == BuiltinTypeSpec.Type.String && string_labels.Count > 6) {
5250 ResolveStringSwitchMap (ec);
5254 // Anonymous storey initialization has to happen before
5255 // any generated switch dispatch
5257 block.InsertStatement (0, new DispatchStatement (this));
5262 bool HasOnlyDefaultSection ()
5264 for (int i = 0; i < block.Statements.Count; ++i) {
5265 var s = block.Statements[i] as SwitchLabel;
5267 if (s == null || s.IsDefault)
5276 public override Reachability MarkReachable (Reachability rc)
5278 if (rc.IsUnreachable)
5281 base.MarkReachable (rc);
5283 block.MarkReachableScope (rc);
5285 if (block.Statements.Count == 0)
5288 SwitchLabel constant_label = null;
5289 var constant = new_expr as Constant;
5291 if (constant != null) {
5292 constant_label = FindLabel (constant) ?? case_default;
5293 if (constant_label == null) {
5294 block.Statements.RemoveAt (0);
5299 var section_rc = new Reachability ();
5300 SwitchLabel prev_label = null;
5302 for (int i = 0; i < block.Statements.Count; ++i) {
5303 var s = block.Statements[i];
5304 var sl = s as SwitchLabel;
5306 if (sl != null && sl.SectionStart) {
5308 // Section is marked already via goto case
5310 if (!sl.IsUnreachable) {
5311 section_rc = new Reachability ();
5315 if (constant_label != null && constant_label != sl)
5316 section_rc = Reachability.CreateUnreachable ();
5317 else if (section_rc.IsUnreachable) {
5318 section_rc = new Reachability ();
5320 if (prev_label != null) {
5321 sl.SectionStart = false;
5322 s = new MissingBreak (prev_label);
5323 s.MarkReachable (rc);
5324 block.Statements.Insert (i - 1, s);
5332 section_rc = s.MarkReachable (section_rc);
5335 if (!section_rc.IsUnreachable && prev_label != null) {
5336 prev_label.SectionStart = false;
5337 var s = new MissingBreak (prev_label) {
5341 s.MarkReachable (rc);
5342 block.Statements.Add (s);
5346 // Reachability can affect parent only when all possible paths are handled but
5347 // we still need to run reachability check on switch body to check for fall-through
5349 if (case_default == null && constant_label == null)
5353 // We have at least one local exit from the switch
5358 return Reachability.CreateUnreachable ();
5361 public void RegisterGotoCase (GotoCase gotoCase, Constant value)
5363 if (goto_cases == null)
5364 goto_cases = new List<Tuple<GotoCase, Constant>> ();
5366 goto_cases.Add (Tuple.Create (gotoCase, value));
5370 // Converts string switch into string hashtable
5372 void ResolveStringSwitchMap (ResolveContext ec)
5374 FullNamedExpression string_dictionary_type;
5375 if (ec.Module.PredefinedTypes.Dictionary.Define ()) {
5376 string_dictionary_type = new TypeExpression (
5377 ec.Module.PredefinedTypes.Dictionary.TypeSpec.MakeGenericType (ec,
5378 new [] { ec.BuiltinTypes.String, ec.BuiltinTypes.Int }),
5380 } else if (ec.Module.PredefinedTypes.Hashtable.Define ()) {
5381 string_dictionary_type = new TypeExpression (ec.Module.PredefinedTypes.Hashtable.TypeSpec, loc);
5383 ec.Module.PredefinedTypes.Dictionary.Resolve ();
5387 var ctype = ec.CurrentMemberDefinition.Parent.PartialContainer;
5388 Field field = new Field (ctype, string_dictionary_type,
5389 Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
5390 new MemberName (CompilerGeneratedContainer.MakeName (null, "f", "switch$map", ec.Module.CounterSwitchTypes++), loc), null);
5391 if (!field.Define ())
5393 ctype.AddField (field);
5395 var init = new List<Expression> ();
5397 labels = new Dictionary<long, SwitchLabel> (string_labels.Count);
5398 string value = null;
5400 foreach (SwitchLabel sl in case_labels) {
5402 if (sl.SectionStart)
5403 labels.Add (++counter, sl);
5405 if (sl == case_default || sl == case_null)
5408 value = (string) sl.Converted.GetValue ();
5409 var init_args = new List<Expression> (2);
5410 init_args.Add (new StringLiteral (ec.BuiltinTypes, value, sl.Location));
5412 sl.Converted = new IntConstant (ec.BuiltinTypes, counter, loc);
5413 init_args.Add (sl.Converted);
5415 init.Add (new CollectionElementInitializer (init_args, loc));
5418 Arguments args = new Arguments (1);
5419 args.Add (new Argument (new IntConstant (ec.BuiltinTypes, init.Count, loc)));
5420 Expression initializer = new NewInitialize (string_dictionary_type, args,
5421 new CollectionOrObjectInitializers (init, loc), loc);
5423 switch_cache_field = new FieldExpr (field, loc);
5424 string_dictionary = new SimpleAssign (switch_cache_field, initializer.Resolve (ec));
5427 void DoEmitStringSwitch (EmitContext ec)
5429 Label l_initialized = ec.DefineLabel ();
5432 // Skip initialization when value is null
5434 value.EmitBranchable (ec, nullLabel, false);
5437 // Check if string dictionary is initialized and initialize
5439 switch_cache_field.EmitBranchable (ec, l_initialized, true);
5440 using (ec.With (BuilderContext.Options.OmitDebugInfo, true)) {
5441 string_dictionary.EmitStatement (ec);
5443 ec.MarkLabel (l_initialized);
5445 LocalTemporary string_switch_variable = new LocalTemporary (ec.BuiltinTypes.Int);
5447 ResolveContext rc = new ResolveContext (ec.MemberContext);
5449 if (switch_cache_field.Type.IsGeneric) {
5450 Arguments get_value_args = new Arguments (2);
5451 get_value_args.Add (new Argument (value));
5452 get_value_args.Add (new Argument (string_switch_variable, Argument.AType.Out));
5453 Expression get_item = new Invocation (new MemberAccess (switch_cache_field, "TryGetValue", loc), get_value_args).Resolve (rc);
5454 if (get_item == null)
5458 // A value was not found, go to default case
5460 get_item.EmitBranchable (ec, defaultLabel, false);
5462 Arguments get_value_args = new Arguments (1);
5463 get_value_args.Add (new Argument (value));
5465 Expression get_item = new ElementAccess (switch_cache_field, get_value_args, loc).Resolve (rc);
5466 if (get_item == null)
5469 LocalTemporary get_item_object = new LocalTemporary (ec.BuiltinTypes.Object);
5470 get_item_object.EmitAssign (ec, get_item, true, false);
5471 ec.Emit (OpCodes.Brfalse, defaultLabel);
5473 ExpressionStatement get_item_int = (ExpressionStatement) new SimpleAssign (string_switch_variable,
5474 new Cast (new TypeExpression (ec.BuiltinTypes.Int, loc), get_item_object, loc)).Resolve (rc);
5476 get_item_int.EmitStatement (ec);
5477 get_item_object.Release (ec);
5480 EmitTableSwitch (ec, string_switch_variable);
5481 string_switch_variable.Release (ec);
5485 // Emits switch using simple if/else comparison for small label count (4 + optional default)
5487 void EmitShortSwitch (EmitContext ec)
5489 MethodSpec equal_method = null;
5490 if (SwitchType.BuiltinType == BuiltinTypeSpec.Type.String) {
5491 equal_method = ec.Module.PredefinedMembers.StringEqual.Resolve (loc);
5494 if (equal_method != null) {
5495 value.EmitBranchable (ec, nullLabel, false);
5498 for (int i = 0; i < case_labels.Count; ++i) {
5499 var label = case_labels [i];
5500 if (label == case_default || label == case_null)
5503 var constant = label.Converted;
5505 if (constant == null) {
5506 label.Label.EmitBranchable (ec, label.GetILLabel (ec), true);
5510 if (equal_method != null) {
5514 var call = new CallEmitter ();
5515 call.EmitPredefined (ec, equal_method, new Arguments (0));
5516 ec.Emit (OpCodes.Brtrue, label.GetILLabel (ec));
5520 if (constant.IsZeroInteger && constant.Type.BuiltinType != BuiltinTypeSpec.Type.Long && constant.Type.BuiltinType != BuiltinTypeSpec.Type.ULong) {
5521 value.EmitBranchable (ec, label.GetILLabel (ec), false);
5527 ec.Emit (OpCodes.Beq, label.GetILLabel (ec));
5530 ec.Emit (OpCodes.Br, defaultLabel);
5533 void EmitDispatch (EmitContext ec)
5535 if (IsPatternMatching) {
5536 EmitShortSwitch (ec);
5540 if (value == null) {
5542 // Constant switch, we've already done the work if there is only 1 label
5546 foreach (var sl in case_labels) {
5547 if (sl.IsUnreachable)
5550 if (reachable++ > 0) {
5551 var constant = (Constant) new_expr;
5552 var constant_label = FindLabel (constant) ?? case_default;
5554 ec.Emit (OpCodes.Br, constant_label.GetILLabel (ec));
5562 if (string_dictionary != null) {
5563 DoEmitStringSwitch (ec);
5564 } else if (case_labels.Count < 4 || string_labels != null) {
5565 EmitShortSwitch (ec);
5567 EmitTableSwitch (ec, value);
5571 protected override void DoEmit (EmitContext ec)
5574 // Setup the codegen context
5576 Label old_end = ec.LoopEnd;
5577 Switch old_switch = ec.Switch;
5579 ec.LoopEnd = ec.DefineLabel ();
5582 defaultLabel = case_default == null ? ec.LoopEnd : case_default.GetILLabel (ec);
5583 nullLabel = case_null == null ? defaultLabel : case_null.GetILLabel (ec);
5585 if (value != null) {
5588 var switch_expr = new_expr ?? Expr;
5590 unwrap.EmitCheck (ec);
5591 ec.Emit (OpCodes.Brfalse, nullLabel);
5592 value.EmitAssign (ec, switch_expr, false, false);
5593 } else if (switch_expr != value) {
5594 value.EmitAssign (ec, switch_expr, false, false);
5599 // Next statement is compiler generated we don't need extra
5600 // nop when we can use the statement for sequence point
5602 ec.Mark (block.StartLocation);
5603 block.IsCompilerGenerated = true;
5605 new_expr.EmitSideEffect (ec);
5610 // Restore context state.
5611 ec.MarkLabel (ec.LoopEnd);
5614 // Restore the previous context
5616 ec.LoopEnd = old_end;
5617 ec.Switch = old_switch;
5620 protected override void CloneTo (CloneContext clonectx, Statement t)
5622 Switch target = (Switch) t;
5624 target.Expr = Expr.Clone (clonectx);
5625 target.Statement = target.block = (ExplicitBlock) block.Clone (clonectx);
5628 public override object Accept (StructuralVisitor visitor)
5630 return visitor.Visit (this);
5633 public override void AddEndDefiniteAssignment (FlowAnalysisContext fc)
5635 if (case_default == null && !(new_expr is Constant))
5638 if (end_reachable_das == null)
5639 end_reachable_das = new List<DefiniteAssignmentBitSet> ();
5641 end_reachable_das.Add (fc.DefiniteAssignment);
5644 public override void SetEndReachable ()
5646 end_reachable = true;
5650 // A place where execution can restart in a state machine
5651 public abstract class ResumableStatement : Statement
5654 protected Label resume_point;
5656 public Label PrepareForEmit (EmitContext ec)
5660 resume_point = ec.DefineLabel ();
5662 return resume_point;
5665 public virtual Label PrepareForDispose (EmitContext ec, Label end)
5670 public virtual void EmitForDispose (EmitContext ec, LocalBuilder pc, Label end, bool have_dispatcher)
5675 public abstract class TryFinallyBlock : ExceptionStatement
5677 protected Statement stmt;
5678 Label dispose_try_block;
5679 bool prepared_for_dispose, emitted_dispose;
5680 Method finally_host;
5682 protected TryFinallyBlock (Statement stmt, Location loc)
5690 public Statement Statement {
5698 protected abstract void EmitTryBody (EmitContext ec);
5699 public abstract void EmitFinallyBody (EmitContext ec);
5701 public override Label PrepareForDispose (EmitContext ec, Label end)
5703 if (!prepared_for_dispose) {
5704 prepared_for_dispose = true;
5705 dispose_try_block = ec.DefineLabel ();
5707 return dispose_try_block;
5710 protected sealed override void DoEmit (EmitContext ec)
5712 EmitTryBodyPrepare (ec);
5715 bool beginFinally = EmitBeginFinallyBlock (ec);
5717 Label start_finally = ec.DefineLabel ();
5718 if (resume_points != null && beginFinally) {
5719 var state_machine = (StateMachineInitializer) ec.CurrentAnonymousMethod;
5721 ec.Emit (OpCodes.Ldloc, state_machine.SkipFinally);
5722 ec.Emit (OpCodes.Brfalse_S, start_finally);
5723 ec.Emit (OpCodes.Endfinally);
5726 ec.MarkLabel (start_finally);
5728 if (finally_host != null) {
5729 finally_host.Define ();
5730 finally_host.PrepareEmit ();
5731 finally_host.Emit ();
5733 // Now it's safe to add, to close it properly and emit sequence points
5734 finally_host.Parent.AddMember (finally_host);
5736 var ce = new CallEmitter ();
5737 ce.InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, loc);
5738 ce.EmitPredefined (ec, finally_host.Spec, new Arguments (0), true);
5740 EmitFinallyBody (ec);
5744 ec.EndExceptionBlock ();
5747 public override void EmitForDispose (EmitContext ec, LocalBuilder pc, Label end, bool have_dispatcher)
5749 if (emitted_dispose)
5752 emitted_dispose = true;
5754 Label end_of_try = ec.DefineLabel ();
5756 // Ensure that the only way we can get into this code is through a dispatcher
5757 if (have_dispatcher)
5758 ec.Emit (OpCodes.Br, end);
5760 ec.BeginExceptionBlock ();
5762 ec.MarkLabel (dispose_try_block);
5764 Label[] labels = null;
5765 for (int i = 0; i < resume_points.Count; ++i) {
5766 ResumableStatement s = resume_points[i];
5767 Label ret = s.PrepareForDispose (ec, end_of_try);
5768 if (ret.Equals (end_of_try) && labels == null)
5770 if (labels == null) {
5771 labels = new Label[resume_points.Count];
5772 for (int j = 0; j < i; ++j)
5773 labels[j] = end_of_try;
5778 if (labels != null) {
5780 for (j = 1; j < labels.Length; ++j)
5781 if (!labels[0].Equals (labels[j]))
5783 bool emit_dispatcher = j < labels.Length;
5785 if (emit_dispatcher) {
5786 ec.Emit (OpCodes.Ldloc, pc);
5787 ec.EmitInt (first_resume_pc);
5788 ec.Emit (OpCodes.Sub);
5789 ec.Emit (OpCodes.Switch, labels);
5792 foreach (ResumableStatement s in resume_points)
5793 s.EmitForDispose (ec, pc, end_of_try, emit_dispatcher);
5796 ec.MarkLabel (end_of_try);
5798 ec.BeginFinallyBlock ();
5800 if (finally_host != null) {
5801 var ce = new CallEmitter ();
5802 ce.InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, loc);
5803 ce.EmitPredefined (ec, finally_host.Spec, new Arguments (0), true);
5805 EmitFinallyBody (ec);
5808 ec.EndExceptionBlock ();
5811 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
5813 var res = stmt.FlowAnalysis (fc);
5818 protected virtual bool EmitBeginFinallyBlock (EmitContext ec)
5820 ec.BeginFinallyBlock ();
5824 public override Reachability MarkReachable (Reachability rc)
5826 base.MarkReachable (rc);
5827 return Statement.MarkReachable (rc);
5830 public override bool Resolve (BlockContext bc)
5834 parent = bc.CurrentTryBlock;
5835 bc.CurrentTryBlock = this;
5837 using (bc.Set (ResolveContext.Options.TryScope)) {
5838 ok = stmt.Resolve (bc);
5841 bc.CurrentTryBlock = parent;
5844 // Finally block inside iterator is called from MoveNext and
5845 // Dispose methods that means we need to lift the block into
5846 // newly created host method to emit the body only once. The
5847 // original block then simply calls the newly generated method.
5849 if (bc.CurrentIterator != null && !bc.IsInProbingMode) {
5850 var b = stmt as Block;
5851 if (b != null && b.Explicit.HasYield) {
5852 finally_host = bc.CurrentIterator.CreateFinallyHost (this);
5856 return base.Resolve (bc) && ok;
5861 // Base class for blocks using exception handling
5863 public abstract class ExceptionStatement : ResumableStatement
5865 protected List<ResumableStatement> resume_points;
5866 protected int first_resume_pc;
5867 protected ExceptionStatement parent;
5869 protected ExceptionStatement (Location loc)
5874 protected virtual void EmitBeginException (EmitContext ec)
5876 ec.BeginExceptionBlock ();
5879 protected virtual void EmitTryBodyPrepare (EmitContext ec)
5881 StateMachineInitializer state_machine = null;
5882 if (resume_points != null) {
5883 state_machine = (StateMachineInitializer) ec.CurrentAnonymousMethod;
5885 ec.EmitInt ((int) IteratorStorey.State.Running);
5886 ec.Emit (OpCodes.Stloc, state_machine.CurrentPC);
5889 EmitBeginException (ec);
5891 if (resume_points != null) {
5892 ec.MarkLabel (resume_point);
5894 // For normal control flow, we want to fall-through the Switch
5895 // So, we use CurrentPC rather than the $PC field, and initialize it to an outside value above
5896 ec.Emit (OpCodes.Ldloc, state_machine.CurrentPC);
5897 ec.EmitInt (first_resume_pc);
5898 ec.Emit (OpCodes.Sub);
5900 Label[] labels = new Label[resume_points.Count];
5901 for (int i = 0; i < resume_points.Count; ++i)
5902 labels[i] = resume_points[i].PrepareForEmit (ec);
5903 ec.Emit (OpCodes.Switch, labels);
5907 public virtual int AddResumePoint (ResumableStatement stmt, int pc, StateMachineInitializer stateMachine)
5909 if (parent != null) {
5910 // TODO: MOVE to virtual TryCatch
5911 var tc = this as TryCatch;
5912 var s = tc != null && tc.IsTryCatchFinally ? stmt : this;
5914 pc = parent.AddResumePoint (s, pc, stateMachine);
5916 pc = stateMachine.AddResumePoint (this);
5919 if (resume_points == null) {
5920 resume_points = new List<ResumableStatement> ();
5921 first_resume_pc = pc;
5924 if (pc != first_resume_pc + resume_points.Count)
5925 throw new InternalErrorException ("missed an intervening AddResumePoint?");
5927 resume_points.Add (stmt);
5932 public class Lock : TryFinallyBlock
5935 TemporaryVariableReference expr_copy;
5936 TemporaryVariableReference lock_taken;
5938 public Lock (Expression expr, Statement stmt, Location loc)
5944 public Expression Expr {
5950 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
5952 expr.FlowAnalysis (fc);
5953 return base.DoFlowAnalysis (fc);
5956 public override bool Resolve (BlockContext ec)
5958 expr = expr.Resolve (ec);
5962 if (!TypeSpec.IsReferenceType (expr.Type) && expr.Type != InternalType.ErrorType) {
5963 ec.Report.Error (185, loc,
5964 "`{0}' is not a reference type as required by the lock statement",
5965 expr.Type.GetSignatureForError ());
5968 if (expr.Type.IsGenericParameter) {
5969 expr = Convert.ImplicitTypeParameterConversion (expr, (TypeParameterSpec)expr.Type, ec.BuiltinTypes.Object);
5972 VariableReference lv = expr as VariableReference;
5975 locked = lv.IsLockedByStatement;
5976 lv.IsLockedByStatement = true;
5983 // Have to keep original lock value around to unlock same location
5984 // in the case of original value has changed or is null
5986 expr_copy = TemporaryVariableReference.Create (ec.BuiltinTypes.Object, ec.CurrentBlock, loc);
5987 expr_copy.Resolve (ec);
5990 // Ensure Monitor methods are available
5992 if (ResolvePredefinedMethods (ec) > 1) {
5993 lock_taken = TemporaryVariableReference.Create (ec.BuiltinTypes.Bool, ec.CurrentBlock, loc);
5994 lock_taken.Resolve (ec);
5997 using (ec.Set (ResolveContext.Options.LockScope)) {
6002 lv.IsLockedByStatement = locked;
6008 protected override void EmitTryBodyPrepare (EmitContext ec)
6010 expr_copy.EmitAssign (ec, expr);
6012 if (lock_taken != null) {
6014 // Initialize ref variable
6016 lock_taken.EmitAssign (ec, new BoolLiteral (ec.BuiltinTypes, false, loc));
6019 // Monitor.Enter (expr_copy)
6021 expr_copy.Emit (ec);
6022 ec.Emit (OpCodes.Call, ec.Module.PredefinedMembers.MonitorEnter.Get ());
6025 base.EmitTryBodyPrepare (ec);
6028 protected override void EmitTryBody (EmitContext ec)
6031 // Monitor.Enter (expr_copy, ref lock_taken)
6033 if (lock_taken != null) {
6034 expr_copy.Emit (ec);
6035 lock_taken.LocalInfo.CreateBuilder (ec);
6036 lock_taken.AddressOf (ec, AddressOp.Load);
6037 ec.Emit (OpCodes.Call, ec.Module.PredefinedMembers.MonitorEnter_v4.Get ());
6040 Statement.Emit (ec);
6043 public override void EmitFinallyBody (EmitContext ec)
6046 // if (lock_taken) Monitor.Exit (expr_copy)
6048 Label skip = ec.DefineLabel ();
6050 if (lock_taken != null) {
6051 lock_taken.Emit (ec);
6052 ec.Emit (OpCodes.Brfalse_S, skip);
6055 expr_copy.Emit (ec);
6056 var m = ec.Module.PredefinedMembers.MonitorExit.Resolve (loc);
6058 ec.Emit (OpCodes.Call, m);
6060 ec.MarkLabel (skip);
6063 int ResolvePredefinedMethods (ResolveContext rc)
6065 // Try 4.0 Monitor.Enter (object, ref bool) overload first
6066 var m = rc.Module.PredefinedMembers.MonitorEnter_v4.Get ();
6070 m = rc.Module.PredefinedMembers.MonitorEnter.Get ();
6074 rc.Module.PredefinedMembers.MonitorEnter_v4.Resolve (loc);
6078 protected override void CloneTo (CloneContext clonectx, Statement t)
6080 Lock target = (Lock) t;
6082 target.expr = expr.Clone (clonectx);
6083 target.stmt = Statement.Clone (clonectx);
6086 public override object Accept (StructuralVisitor visitor)
6088 return visitor.Visit (this);
6093 public class Unchecked : Statement {
6096 public Unchecked (Block b, Location loc)
6103 public override bool Resolve (BlockContext ec)
6105 using (ec.With (ResolveContext.Options.AllCheckStateFlags, false))
6106 return Block.Resolve (ec);
6109 protected override void DoEmit (EmitContext ec)
6111 using (ec.With (EmitContext.Options.CheckedScope, false))
6115 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6117 return Block.FlowAnalysis (fc);
6120 public override Reachability MarkReachable (Reachability rc)
6122 base.MarkReachable (rc);
6123 return Block.MarkReachable (rc);
6126 protected override void CloneTo (CloneContext clonectx, Statement t)
6128 Unchecked target = (Unchecked) t;
6130 target.Block = clonectx.LookupBlock (Block);
6133 public override object Accept (StructuralVisitor visitor)
6135 return visitor.Visit (this);
6139 public class Checked : Statement {
6142 public Checked (Block b, Location loc)
6145 b.Unchecked = false;
6149 public override bool Resolve (BlockContext ec)
6151 using (ec.With (ResolveContext.Options.AllCheckStateFlags, true))
6152 return Block.Resolve (ec);
6155 protected override void DoEmit (EmitContext ec)
6157 using (ec.With (EmitContext.Options.CheckedScope, true))
6161 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6163 return Block.FlowAnalysis (fc);
6166 public override Reachability MarkReachable (Reachability rc)
6168 base.MarkReachable (rc);
6169 return Block.MarkReachable (rc);
6172 protected override void CloneTo (CloneContext clonectx, Statement t)
6174 Checked target = (Checked) t;
6176 target.Block = clonectx.LookupBlock (Block);
6179 public override object Accept (StructuralVisitor visitor)
6181 return visitor.Visit (this);
6185 public class Unsafe : Statement {
6188 public Unsafe (Block b, Location loc)
6191 Block.Unsafe = true;
6195 public override bool Resolve (BlockContext ec)
6197 if (ec.CurrentIterator != null)
6198 ec.Report.Error (1629, loc, "Unsafe code may not appear in iterators");
6200 using (ec.Set (ResolveContext.Options.UnsafeScope))
6201 return Block.Resolve (ec);
6204 protected override void DoEmit (EmitContext ec)
6209 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6211 return Block.FlowAnalysis (fc);
6214 public override Reachability MarkReachable (Reachability rc)
6216 base.MarkReachable (rc);
6217 return Block.MarkReachable (rc);
6220 protected override void CloneTo (CloneContext clonectx, Statement t)
6222 Unsafe target = (Unsafe) t;
6224 target.Block = clonectx.LookupBlock (Block);
6227 public override object Accept (StructuralVisitor visitor)
6229 return visitor.Visit (this);
6236 public class Fixed : Statement
6238 abstract class Emitter : ShimExpression
6240 protected LocalVariable vi;
6242 protected Emitter (Expression expr, LocalVariable li)
6248 public abstract void EmitExit (EmitContext ec);
6250 public override void FlowAnalysis (FlowAnalysisContext fc)
6252 expr.FlowAnalysis (fc);
6256 sealed class ExpressionEmitter : Emitter {
6257 public ExpressionEmitter (Expression converted, LocalVariable li)
6258 : base (converted, li)
6262 protected override Expression DoResolve (ResolveContext rc)
6264 throw new NotImplementedException ();
6267 public override void Emit (EmitContext ec) {
6269 // Store pointer in pinned location
6275 public override void EmitExit (EmitContext ec)
6278 ec.Emit (OpCodes.Conv_U);
6283 class StringEmitter : Emitter
6285 LocalVariable pinned_string;
6287 public StringEmitter (Expression expr, LocalVariable li)
6292 protected override Expression DoResolve (ResolveContext rc)
6294 pinned_string = new LocalVariable (vi.Block, "$pinned",
6295 LocalVariable.Flags.FixedVariable | LocalVariable.Flags.CompilerGenerated | LocalVariable.Flags.Used,
6297 pinned_string.Type = rc.BuiltinTypes.String;
6300 eclass = ExprClass.Variable;
6301 type = rc.BuiltinTypes.Int;
6305 public override void Emit (EmitContext ec)
6307 pinned_string.CreateBuilder (ec);
6310 pinned_string.EmitAssign (ec);
6312 // TODO: Should use Binary::Add
6313 pinned_string.Emit (ec);
6314 ec.Emit (OpCodes.Conv_I);
6316 var m = ec.Module.PredefinedMembers.RuntimeHelpersOffsetToStringData.Resolve (loc);
6320 PropertyExpr pe = new PropertyExpr (m, pinned_string.Location);
6321 //pe.InstanceExpression = pinned_string;
6322 pe.Resolve (new ResolveContext (ec.MemberContext)).Emit (ec);
6324 ec.Emit (OpCodes.Add);
6328 public override void EmitExit (EmitContext ec)
6331 pinned_string.EmitAssign (ec);
6335 public class VariableDeclaration : BlockVariable
6337 public VariableDeclaration (FullNamedExpression type, LocalVariable li)
6342 protected override Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
6344 if (!Variable.Type.IsPointer && li == Variable) {
6345 bc.Report.Error (209, TypeExpression.Location,
6346 "The type of locals declared in a fixed statement must be a pointer type");
6350 var res = initializer.Resolve (bc);
6357 var ac = res.Type as ArrayContainer;
6359 TypeSpec array_type = ac.Element;
6362 // Provided that array_type is unmanaged,
6364 if (!TypeManager.VerifyUnmanaged (bc.Module, array_type, loc))
6367 Expression res_init;
6368 if (ExpressionAnalyzer.IsInexpensiveLoad (res)) {
6371 var expr_variable = LocalVariable.CreateCompilerGenerated (ac, bc.CurrentBlock, loc);
6372 res_init = new CompilerAssign (expr_variable.CreateReferenceExpression (bc, loc), res, loc);
6373 res = expr_variable.CreateReferenceExpression (bc, loc);
6377 // and T* is implicitly convertible to the
6378 // pointer type given in the fixed statement.
6380 ArrayPtr array_ptr = new ArrayPtr (res, array_type, loc);
6382 Expression converted = Convert.ImplicitConversionRequired (bc, array_ptr.Resolve (bc), li.Type, loc);
6383 if (converted == null)
6387 // fixed (T* e_ptr = (e == null || e.Length == 0) ? null : converted [0])
6389 converted = new Conditional (new BooleanExpression (new Binary (Binary.Operator.LogicalOr,
6390 new Binary (Binary.Operator.Equality, res_init, new NullLiteral (loc)),
6391 new Binary (Binary.Operator.Equality, new MemberAccess (res, "Length"), new IntConstant (bc.BuiltinTypes, 0, loc)))),
6392 new NullLiteral (loc),
6395 converted = converted.Resolve (bc);
6397 return new ExpressionEmitter (converted, li);
6403 if (res.Type.BuiltinType == BuiltinTypeSpec.Type.String) {
6404 return new StringEmitter (res, li).Resolve (bc);
6407 // Case 3: fixed buffer
6408 if (res is FixedBufferPtr) {
6409 return new ExpressionEmitter (res, li);
6412 bool already_fixed = true;
6415 // Case 4: & object.
6417 Unary u = res as Unary;
6419 if (u.Oper == Unary.Operator.AddressOf) {
6420 IVariableReference vr = u.Expr as IVariableReference;
6421 if (vr == null || !vr.IsFixed) {
6422 already_fixed = false;
6425 } else if (initializer is Cast) {
6426 bc.Report.Error (254, initializer.Location, "The right hand side of a fixed statement assignment may not be a cast expression");
6430 if (already_fixed) {
6431 bc.Report.Error (213, loc, "You cannot use the fixed statement to take the address of an already fixed expression");
6434 res = Convert.ImplicitConversionRequired (bc, res, li.Type, loc);
6435 return new ExpressionEmitter (res, li);
6440 VariableDeclaration decl;
6441 Statement statement;
6444 public Fixed (VariableDeclaration decl, Statement stmt, Location l)
6453 public Statement Statement {
6459 public BlockVariable Variables {
6467 public override bool Resolve (BlockContext bc)
6469 using (bc.Set (ResolveContext.Options.FixedInitializerScope)) {
6470 if (!decl.Resolve (bc))
6474 return statement.Resolve (bc);
6477 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6479 decl.FlowAnalysis (fc);
6480 return statement.FlowAnalysis (fc);
6483 protected override void DoEmit (EmitContext ec)
6485 decl.Variable.CreateBuilder (ec);
6486 decl.Initializer.Emit (ec);
6487 if (decl.Declarators != null) {
6488 foreach (var d in decl.Declarators) {
6489 d.Variable.CreateBuilder (ec);
6490 d.Initializer.Emit (ec);
6494 statement.Emit (ec);
6500 // Clear the pinned variable
6502 ((Emitter) decl.Initializer).EmitExit (ec);
6503 if (decl.Declarators != null) {
6504 foreach (var d in decl.Declarators) {
6505 ((Emitter)d.Initializer).EmitExit (ec);
6510 public override Reachability MarkReachable (Reachability rc)
6512 base.MarkReachable (rc);
6514 decl.MarkReachable (rc);
6516 rc = statement.MarkReachable (rc);
6518 // TODO: What if there is local exit?
6519 has_ret = rc.IsUnreachable;
6523 protected override void CloneTo (CloneContext clonectx, Statement t)
6525 Fixed target = (Fixed) t;
6527 target.decl = (VariableDeclaration) decl.Clone (clonectx);
6528 target.statement = statement.Clone (clonectx);
6531 public override object Accept (StructuralVisitor visitor)
6533 return visitor.Visit (this);
6537 public class Catch : Statement
6539 class CatchVariableStore : Statement
6541 readonly Catch ctch;
6543 public CatchVariableStore (Catch ctch)
6548 protected override void CloneTo (CloneContext clonectx, Statement target)
6552 protected override void DoEmit (EmitContext ec)
6554 // Emits catch variable debug information inside correct block
6555 ctch.EmitCatchVariableStore (ec);
6558 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6564 class FilterStatement : Statement
6566 readonly Catch ctch;
6568 public FilterStatement (Catch ctch)
6573 protected override void CloneTo (CloneContext clonectx, Statement target)
6577 protected override void DoEmit (EmitContext ec)
6579 if (ctch.li != null) {
6580 if (ctch.hoisted_temp != null)
6581 ctch.hoisted_temp.Emit (ec);
6585 if (!ctch.IsGeneral && ctch.type.Kind == MemberKind.TypeParameter)
6586 ec.Emit (OpCodes.Box, ctch.type);
6589 var expr_start = ec.DefineLabel ();
6590 var end = ec.DefineLabel ();
6592 ec.Emit (OpCodes.Brtrue_S, expr_start);
6594 ec.Emit (OpCodes.Br, end);
6595 ec.MarkLabel (expr_start);
6597 ctch.Filter.Emit (ec);
6600 ec.Emit (OpCodes.Endfilter);
6601 ec.BeginFilterHandler ();
6602 ec.Emit (OpCodes.Pop);
6605 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6607 ctch.Filter.FlowAnalysis (fc);
6611 public override bool Resolve (BlockContext bc)
6613 ctch.Filter = ctch.Filter.Resolve (bc);
6615 if (ctch.Filter != null) {
6616 if (ctch.Filter.ContainsEmitWithAwait ()) {
6617 bc.Report.Error (7094, ctch.Filter.Location, "The `await' operator cannot be used in the filter expression of a catch clause");
6620 var c = ctch.Filter as Constant;
6621 if (c != null && !c.IsDefaultValue) {
6622 bc.Report.Warning (7095, 1, ctch.Filter.Location, "Exception filter expression is a constant");
6630 ExplicitBlock block;
6632 FullNamedExpression type_expr;
6633 CompilerAssign assign;
6635 LocalTemporary hoisted_temp;
6637 public Catch (ExplicitBlock block, Location loc)
6645 public ExplicitBlock Block {
6651 public TypeSpec CatchType {
6657 public Expression Filter {
6661 public bool IsGeneral {
6663 return type_expr == null;
6667 public FullNamedExpression TypeExpression {
6676 public LocalVariable Variable {
6687 protected override void DoEmit (EmitContext ec)
6689 if (Filter != null) {
6690 ec.BeginExceptionFilterBlock ();
6691 ec.Emit (OpCodes.Isinst, IsGeneral ? ec.BuiltinTypes.Object : CatchType);
6693 if (Block.HasAwait) {
6694 Block.EmitScopeInitialization (ec);
6703 ec.BeginCatchBlock (ec.BuiltinTypes.Object);
6705 ec.BeginCatchBlock (CatchType);
6708 ec.Emit (OpCodes.Pop);
6710 if (Block.HasAwait) {
6712 EmitCatchVariableStore (ec);
6718 void EmitCatchVariableStore (EmitContext ec)
6720 li.CreateBuilder (ec);
6723 // For hoisted catch variable we have to use a temporary local variable
6724 // for captured variable initialization during storey setup because variable
6725 // needs to be on the stack after storey instance for stfld operation
6727 if (li.HoistedVariant != null) {
6728 hoisted_temp = new LocalTemporary (li.Type);
6729 hoisted_temp.Store (ec);
6731 // switch to assignment from temporary variable and not from top of the stack
6732 assign.UpdateSource (hoisted_temp);
6736 public override bool Resolve (BlockContext bc)
6738 using (bc.Set (ResolveContext.Options.CatchScope)) {
6739 if (type_expr == null) {
6740 if (CreateExceptionVariable (bc.Module.Compiler.BuiltinTypes.Object)) {
6741 if (!block.HasAwait || Filter != null)
6742 block.AddScopeStatement (new CatchVariableStore (this));
6744 Expression source = new EmptyExpression (li.Type);
6745 assign = new CompilerAssign (new LocalVariableReference (li, Location.Null), source, Location.Null);
6746 Block.AddScopeStatement (new StatementExpression (assign, Location.Null));
6749 type = type_expr.ResolveAsType (bc);
6754 CreateExceptionVariable (type);
6756 if (type.BuiltinType != BuiltinTypeSpec.Type.Exception && !TypeSpec.IsBaseClass (type, bc.BuiltinTypes.Exception, false)) {
6757 bc.Report.Error (155, loc, "The type caught or thrown must be derived from System.Exception");
6758 } else if (li != null) {
6760 li.PrepareAssignmentAnalysis (bc);
6762 // source variable is at the top of the stack
6763 Expression source = new EmptyExpression (li.Type);
6764 if (li.Type.IsGenericParameter)
6765 source = new UnboxCast (source, li.Type);
6767 if (!block.HasAwait || Filter != null)
6768 block.AddScopeStatement (new CatchVariableStore (this));
6771 // Uses Location.Null to hide from symbol file
6773 assign = new CompilerAssign (new LocalVariableReference (li, Location.Null), source, Location.Null);
6774 Block.AddScopeStatement (new StatementExpression (assign, Location.Null));
6778 if (Filter != null) {
6779 Block.AddScopeStatement (new FilterStatement (this));
6782 Block.SetCatchBlock ();
6783 return Block.Resolve (bc);
6787 bool CreateExceptionVariable (TypeSpec type)
6789 if (!Block.HasAwait)
6792 // TODO: Scan the block for rethrow expression
6793 //if (!Block.HasRethrow)
6796 li = LocalVariable.CreateCompilerGenerated (type, block, Location.Null);
6800 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6802 if (li != null && !li.IsCompilerGenerated) {
6803 fc.SetVariableAssigned (li.VariableInfo, true);
6806 return block.FlowAnalysis (fc);
6809 public override Reachability MarkReachable (Reachability rc)
6811 base.MarkReachable (rc);
6813 var c = Filter as Constant;
6814 if (c != null && c.IsDefaultValue)
6815 return Reachability.CreateUnreachable ();
6817 return block.MarkReachable (rc);
6820 protected override void CloneTo (CloneContext clonectx, Statement t)
6822 Catch target = (Catch) t;
6824 if (type_expr != null)
6825 target.type_expr = (FullNamedExpression) type_expr.Clone (clonectx);
6828 target.Filter = Filter.Clone (clonectx);
6830 target.block = (ExplicitBlock) clonectx.LookupBlock (block);
6834 public class TryFinally : TryFinallyBlock
6837 List<DefiniteAssignmentBitSet> try_exit_dat;
6838 List<Label> redirected_jumps;
6839 Label? start_fin_label;
6841 public TryFinally (Statement stmt, ExplicitBlock fini, Location loc)
6847 public ExplicitBlock FinallyBlock {
6853 public void RegisterForControlExitCheck (DefiniteAssignmentBitSet vector)
6855 if (try_exit_dat == null)
6856 try_exit_dat = new List<DefiniteAssignmentBitSet> ();
6858 try_exit_dat.Add (vector);
6861 public override bool Resolve (BlockContext bc)
6863 bool ok = base.Resolve (bc);
6865 fini.SetFinallyBlock ();
6866 using (bc.Set (ResolveContext.Options.FinallyScope)) {
6867 ok &= fini.Resolve (bc);
6873 protected override void EmitBeginException (EmitContext ec)
6875 if (fini.HasAwait && stmt is TryCatch)
6876 ec.BeginExceptionBlock ();
6878 base.EmitBeginException (ec);
6881 protected override void EmitTryBody (EmitContext ec)
6883 if (fini.HasAwait) {
6884 if (ec.TryFinallyUnwind == null)
6885 ec.TryFinallyUnwind = new List<TryFinally> ();
6887 ec.TryFinallyUnwind.Add (this);
6890 if (stmt is TryCatch)
6891 ec.EndExceptionBlock ();
6893 ec.TryFinallyUnwind.Remove (this);
6895 if (start_fin_label != null)
6896 ec.MarkLabel (start_fin_label.Value);
6904 protected override bool EmitBeginFinallyBlock (EmitContext ec)
6909 return base.EmitBeginFinallyBlock (ec);
6912 public override void EmitFinallyBody (EmitContext ec)
6914 if (!fini.HasAwait) {
6920 // Emits catch block like
6922 // catch (object temp) {
6923 // this.exception_field = temp;
6926 var type = ec.BuiltinTypes.Object;
6927 ec.BeginCatchBlock (type);
6929 var temp = ec.GetTemporaryLocal (type);
6930 ec.Emit (OpCodes.Stloc, temp);
6932 var exception_field = ec.GetTemporaryField (type);
6934 ec.Emit (OpCodes.Ldloc, temp);
6935 exception_field.EmitAssignFromStack (ec);
6937 ec.EndExceptionBlock ();
6939 ec.FreeTemporaryLocal (temp, type);
6944 // Emits exception rethrow
6946 // if (this.exception_field != null)
6947 // throw this.exception_field;
6949 exception_field.Emit (ec);
6950 var skip_throw = ec.DefineLabel ();
6951 ec.Emit (OpCodes.Brfalse_S, skip_throw);
6952 exception_field.Emit (ec);
6953 ec.Emit (OpCodes.Throw);
6954 ec.MarkLabel (skip_throw);
6956 exception_field.IsAvailableForReuse = true;
6958 EmitUnwindFinallyTable (ec);
6961 bool IsParentBlock (Block block)
6963 for (Block b = fini; b != null; b = b.Parent) {
6971 public static Label EmitRedirectedJump (EmitContext ec, AsyncInitializer initializer, Label label, Block labelBlock)
6974 if (labelBlock != null) {
6975 for (idx = ec.TryFinallyUnwind.Count; idx != 0; --idx) {
6976 var fin = ec.TryFinallyUnwind [idx - 1];
6977 if (!fin.IsParentBlock (labelBlock))
6984 bool set_return_state = true;
6986 for (; idx < ec.TryFinallyUnwind.Count; ++idx) {
6987 var fin = ec.TryFinallyUnwind [idx];
6988 if (labelBlock != null && !fin.IsParentBlock (labelBlock))
6991 fin.EmitRedirectedExit (ec, label, initializer, set_return_state);
6992 set_return_state = false;
6994 if (fin.start_fin_label == null) {
6995 fin.start_fin_label = ec.DefineLabel ();
6998 label = fin.start_fin_label.Value;
7004 public static Label EmitRedirectedReturn (EmitContext ec, AsyncInitializer initializer)
7006 return EmitRedirectedJump (ec, initializer, initializer.BodyEnd, null);
7009 void EmitRedirectedExit (EmitContext ec, Label label, AsyncInitializer initializer, bool setReturnState)
7011 if (redirected_jumps == null) {
7012 redirected_jumps = new List<Label> ();
7014 // Add fallthrough label
7015 redirected_jumps.Add (ec.DefineLabel ());
7018 initializer.HoistedReturnState = ec.GetTemporaryField (ec.Module.Compiler.BuiltinTypes.Int, true);
7021 int index = redirected_jumps.IndexOf (label);
7023 redirected_jumps.Add (label);
7024 index = redirected_jumps.Count - 1;
7028 // Indicates we have captured exit jump
7030 if (setReturnState) {
7031 var value = new IntConstant (initializer.HoistedReturnState.Type, index, Location.Null);
7032 initializer.HoistedReturnState.EmitAssign (ec, value, false, false);
7037 // Emits state table of jumps outside of try block and reload of return
7038 // value when try block returns value
7040 void EmitUnwindFinallyTable (EmitContext ec)
7042 if (redirected_jumps == null)
7045 var initializer = (AsyncInitializer)ec.CurrentAnonymousMethod;
7046 initializer.HoistedReturnState.EmitLoad (ec);
7047 ec.Emit (OpCodes.Switch, redirected_jumps.ToArray ());
7049 // Mark fallthrough label
7050 ec.MarkLabel (redirected_jumps [0]);
7053 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7055 var da = fc.BranchDefiniteAssignment ();
7057 var tf = fc.TryFinally;
7058 fc.TryFinally = this;
7060 var res_stmt = Statement.FlowAnalysis (fc);
7064 var try_da = fc.DefiniteAssignment;
7065 fc.DefiniteAssignment = da;
7067 var res_fin = fini.FlowAnalysis (fc);
7069 if (try_exit_dat != null) {
7071 // try block has global exit but we need to run definite assignment check
7072 // for parameter block out parameter after finally block because it's always
7073 // executed before exit
7075 foreach (var try_da_part in try_exit_dat)
7076 fc.ParametersBlock.CheckControlExit (fc, fc.DefiniteAssignment | try_da_part);
7078 try_exit_dat = null;
7081 fc.DefiniteAssignment |= try_da;
7082 return res_stmt | res_fin;
7085 public override Reachability MarkReachable (Reachability rc)
7088 // Mark finally block first for any exit statement in try block
7089 // to know whether the code which follows finally is reachable
7091 return fini.MarkReachable (rc) | base.MarkReachable (rc);
7094 protected override void CloneTo (CloneContext clonectx, Statement t)
7096 TryFinally target = (TryFinally) t;
7098 target.stmt = stmt.Clone (clonectx);
7100 target.fini = (ExplicitBlock) clonectx.LookupBlock (fini);
7103 public override object Accept (StructuralVisitor visitor)
7105 return visitor.Visit (this);
7109 public class TryCatch : ExceptionStatement
7112 List<Catch> clauses;
7113 readonly bool inside_try_finally;
7114 List<Catch> catch_sm;
7116 public TryCatch (Block block, List<Catch> catch_clauses, Location l, bool inside_try_finally)
7120 this.clauses = catch_clauses;
7121 this.inside_try_finally = inside_try_finally;
7124 public List<Catch> Clauses {
7130 public bool IsTryCatchFinally {
7132 return inside_try_finally;
7136 public override bool Resolve (BlockContext bc)
7140 using (bc.Set (ResolveContext.Options.TryScope)) {
7141 parent = bc.CurrentTryBlock;
7143 if (IsTryCatchFinally) {
7144 ok = Block.Resolve (bc);
7146 using (bc.Set (ResolveContext.Options.TryWithCatchScope)) {
7147 bc.CurrentTryBlock = this;
7148 ok = Block.Resolve (bc);
7149 bc.CurrentTryBlock = parent;
7154 for (int i = 0; i < clauses.Count; ++i) {
7157 ok &= c.Resolve (bc);
7159 if (c.Block.HasAwait) {
7160 if (catch_sm == null)
7161 catch_sm = new List<Catch> ();
7166 if (c.Filter != null)
7169 TypeSpec resolved_type = c.CatchType;
7170 if (resolved_type == null)
7173 for (int ii = 0; ii < clauses.Count; ++ii) {
7177 if (clauses[ii].Filter != null)
7180 if (clauses[ii].IsGeneral) {
7181 if (resolved_type.BuiltinType != BuiltinTypeSpec.Type.Exception)
7184 if (!bc.Module.DeclaringAssembly.WrapNonExceptionThrows)
7187 if (!bc.Module.PredefinedAttributes.RuntimeCompatibility.IsDefined)
7190 bc.Report.Warning (1058, 1, c.loc,
7191 "A previous catch clause already catches all exceptions. All non-exceptions thrown will be wrapped in a `System.Runtime.CompilerServices.RuntimeWrappedException'");
7199 var ct = clauses[ii].CatchType;
7203 if (resolved_type == ct || TypeSpec.IsBaseClass (resolved_type, ct, true)) {
7204 bc.Report.Error (160, c.loc,
7205 "A previous catch clause already catches all exceptions of this or a super type `{0}'",
7206 ct.GetSignatureForError ());
7212 return base.Resolve (bc) && ok;
7215 protected sealed override void DoEmit (EmitContext ec)
7217 if (!inside_try_finally)
7218 EmitTryBodyPrepare (ec);
7222 LocalBuilder state_variable = null;
7223 foreach (Catch c in clauses) {
7226 if (catch_sm != null) {
7227 if (state_variable == null) {
7229 // Cannot reuse temp variable because non-catch path assumes the value is 0
7230 // which may not be true for reused local variable
7232 state_variable = ec.DeclareLocal (ec.Module.Compiler.BuiltinTypes.Int, false);
7235 var index = catch_sm.IndexOf (c);
7239 ec.EmitInt (index + 1);
7240 ec.Emit (OpCodes.Stloc, state_variable);
7244 if (!inside_try_finally)
7245 ec.EndExceptionBlock ();
7247 if (state_variable != null) {
7248 ec.Emit (OpCodes.Ldloc, state_variable);
7250 var labels = new Label [catch_sm.Count + 1];
7251 for (int i = 0; i < labels.Length; ++i) {
7252 labels [i] = ec.DefineLabel ();
7255 var end = ec.DefineLabel ();
7256 ec.Emit (OpCodes.Switch, labels);
7258 // 0 value is default label
7259 ec.MarkLabel (labels [0]);
7260 ec.Emit (OpCodes.Br, end);
7262 var atv = ec.AsyncThrowVariable;
7264 for (int i = 0; i < catch_sm.Count; ++i) {
7265 if (c != null && c.Block.HasReachableClosingBrace)
7266 ec.Emit (OpCodes.Br, end);
7268 ec.MarkLabel (labels [i + 1]);
7270 ec.AsyncThrowVariable = c.Variable;
7273 ec.AsyncThrowVariable = atv;
7279 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7281 var start_fc = fc.BranchDefiniteAssignment ();
7282 var res = Block.FlowAnalysis (fc);
7284 DefiniteAssignmentBitSet try_fc = res ? null : fc.DefiniteAssignment;
7286 foreach (var c in clauses) {
7287 fc.BranchDefiniteAssignment (start_fc);
7288 if (!c.FlowAnalysis (fc)) {
7290 try_fc = fc.DefiniteAssignment;
7292 try_fc &= fc.DefiniteAssignment;
7298 fc.DefiniteAssignment = try_fc ?? start_fc;
7303 public override Reachability MarkReachable (Reachability rc)
7305 if (rc.IsUnreachable)
7308 base.MarkReachable (rc);
7310 var tc_rc = Block.MarkReachable (rc);
7312 foreach (var c in clauses)
7313 tc_rc &= c.MarkReachable (rc);
7318 protected override void CloneTo (CloneContext clonectx, Statement t)
7320 TryCatch target = (TryCatch) t;
7322 target.Block = clonectx.LookupBlock (Block);
7323 if (clauses != null){
7324 target.clauses = new List<Catch> ();
7325 foreach (Catch c in clauses)
7326 target.clauses.Add ((Catch) c.Clone (clonectx));
7330 public override object Accept (StructuralVisitor visitor)
7332 return visitor.Visit (this);
7336 public class Using : TryFinallyBlock
7338 public class VariableDeclaration : BlockVariable
7340 Statement dispose_call;
7342 public VariableDeclaration (FullNamedExpression type, LocalVariable li)
7347 public VariableDeclaration (LocalVariable li, Location loc)
7354 public VariableDeclaration (Expression expr)
7357 loc = expr.Location;
7363 public bool IsNested { get; private set; }
7367 public void EmitDispose (EmitContext ec)
7369 dispose_call.Emit (ec);
7372 public override bool Resolve (BlockContext bc)
7377 return base.Resolve (bc, false);
7380 public Expression ResolveExpression (BlockContext bc)
7382 var e = Initializer.Resolve (bc);
7386 li = LocalVariable.CreateCompilerGenerated (e.Type, bc.CurrentBlock, loc);
7387 Initializer = ResolveInitializer (bc, Variable, e);
7391 protected override Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
7393 if (li.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
7394 initializer = initializer.Resolve (bc);
7395 if (initializer == null)
7398 // Once there is dynamic used defer conversion to runtime even if we know it will never succeed
7399 Arguments args = new Arguments (1);
7400 args.Add (new Argument (initializer));
7401 initializer = new DynamicConversion (bc.BuiltinTypes.IDisposable, 0, args, initializer.Location).Resolve (bc);
7402 if (initializer == null)
7405 var var = LocalVariable.CreateCompilerGenerated (initializer.Type, bc.CurrentBlock, loc);
7406 dispose_call = CreateDisposeCall (bc, var);
7407 dispose_call.Resolve (bc);
7409 return base.ResolveInitializer (bc, li, new SimpleAssign (var.CreateReferenceExpression (bc, loc), initializer, loc));
7412 if (li == Variable) {
7413 CheckIDiposableConversion (bc, li, initializer);
7414 dispose_call = CreateDisposeCall (bc, li);
7415 dispose_call.Resolve (bc);
7418 return base.ResolveInitializer (bc, li, initializer);
7421 protected virtual void CheckIDiposableConversion (BlockContext bc, LocalVariable li, Expression initializer)
7425 if (type.BuiltinType != BuiltinTypeSpec.Type.IDisposable && !CanConvertToIDisposable (bc, type)) {
7426 if (type.IsNullableType) {
7427 // it's handled in CreateDisposeCall
7431 if (type != InternalType.ErrorType) {
7432 bc.Report.SymbolRelatedToPreviousError (type);
7433 var loc = type_expr == null ? initializer.Location : type_expr.Location;
7434 bc.Report.Error (1674, loc, "`{0}': type used in a using statement must be implicitly convertible to `System.IDisposable'",
7435 type.GetSignatureForError ());
7442 static bool CanConvertToIDisposable (BlockContext bc, TypeSpec type)
7444 var target = bc.BuiltinTypes.IDisposable;
7445 var tp = type as TypeParameterSpec;
7447 return Convert.ImplicitTypeParameterConversion (null, tp, target) != null;
7449 return type.ImplementsInterface (target, false);
7452 protected virtual Statement CreateDisposeCall (BlockContext bc, LocalVariable lv)
7454 var lvr = lv.CreateReferenceExpression (bc, lv.Location);
7456 var loc = lv.Location;
7458 var idt = bc.BuiltinTypes.IDisposable;
7459 var m = bc.Module.PredefinedMembers.IDisposableDispose.Resolve (loc);
7461 var dispose_mg = MethodGroupExpr.CreatePredefined (m, idt, loc);
7462 dispose_mg.InstanceExpression = type.IsNullableType ?
7463 new Cast (new TypeExpression (idt, loc), lvr, loc).Resolve (bc) :
7467 // Hide it from symbol file via null location
7469 Statement dispose = new StatementExpression (new Invocation (dispose_mg, null), Location.Null);
7471 // Add conditional call when disposing possible null variable
7472 if (!TypeSpec.IsValueType (type) || type.IsNullableType)
7473 dispose = new If (new Binary (Binary.Operator.Inequality, lvr, new NullLiteral (loc)), dispose, dispose.loc);
7478 public void ResolveDeclaratorInitializer (BlockContext bc)
7480 Initializer = base.ResolveInitializer (bc, Variable, Initializer);
7483 public Statement RewriteUsingDeclarators (BlockContext bc, Statement stmt)
7485 for (int i = declarators.Count - 1; i >= 0; --i) {
7486 var d = declarators [i];
7487 var vd = new VariableDeclaration (d.Variable, d.Variable.Location);
7488 vd.Initializer = d.Initializer;
7490 vd.dispose_call = CreateDisposeCall (bc, d.Variable);
7491 vd.dispose_call.Resolve (bc);
7493 stmt = new Using (vd, stmt, d.Variable.Location);
7500 public override object Accept (StructuralVisitor visitor)
7502 return visitor.Visit (this);
7506 VariableDeclaration decl;
7508 public Using (VariableDeclaration decl, Statement stmt, Location loc)
7514 public Using (Expression expr, Statement stmt, Location loc)
7517 this.decl = new VariableDeclaration (expr);
7522 public Expression Expr {
7524 return decl.Variable == null ? decl.Initializer : null;
7528 public BlockVariable Variables {
7536 public override void Emit (EmitContext ec)
7539 // Don't emit sequence point it will be set on variable declaration
7544 protected override void EmitTryBodyPrepare (EmitContext ec)
7547 base.EmitTryBodyPrepare (ec);
7550 protected override void EmitTryBody (EmitContext ec)
7555 public override void EmitFinallyBody (EmitContext ec)
7557 decl.EmitDispose (ec);
7560 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7562 decl.FlowAnalysis (fc);
7563 return stmt.FlowAnalysis (fc);
7566 public override Reachability MarkReachable (Reachability rc)
7568 decl.MarkReachable (rc);
7569 return base.MarkReachable (rc);
7572 public override bool Resolve (BlockContext ec)
7574 VariableReference vr;
7575 bool vr_locked = false;
7577 using (ec.Set (ResolveContext.Options.UsingInitializerScope)) {
7578 if (decl.Variable == null) {
7579 vr = decl.ResolveExpression (ec) as VariableReference;
7581 vr_locked = vr.IsLockedByStatement;
7582 vr.IsLockedByStatement = true;
7585 if (decl.IsNested) {
7586 decl.ResolveDeclaratorInitializer (ec);
7588 if (!decl.Resolve (ec))
7591 if (decl.Declarators != null) {
7592 stmt = decl.RewriteUsingDeclarators (ec, stmt);
7600 var ok = base.Resolve (ec);
7603 vr.IsLockedByStatement = vr_locked;
7608 protected override void CloneTo (CloneContext clonectx, Statement t)
7610 Using target = (Using) t;
7612 target.decl = (VariableDeclaration) decl.Clone (clonectx);
7613 target.stmt = stmt.Clone (clonectx);
7616 public override object Accept (StructuralVisitor visitor)
7618 return visitor.Visit (this);
7623 /// Implementation of the foreach C# statement
7625 public class Foreach : LoopStatement
7627 abstract class IteratorStatement : Statement
7629 protected readonly Foreach for_each;
7631 protected IteratorStatement (Foreach @foreach)
7633 this.for_each = @foreach;
7634 this.loc = @foreach.expr.Location;
7637 protected override void CloneTo (CloneContext clonectx, Statement target)
7639 throw new NotImplementedException ();
7642 public override void Emit (EmitContext ec)
7644 if (ec.EmitAccurateDebugInfo) {
7645 ec.Emit (OpCodes.Nop);
7651 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7653 throw new NotImplementedException ();
7657 sealed class ArrayForeach : IteratorStatement
7659 TemporaryVariableReference[] lengths;
7660 Expression [] length_exprs;
7661 StatementExpression[] counter;
7662 TemporaryVariableReference[] variables;
7664 TemporaryVariableReference copy;
7666 public ArrayForeach (Foreach @foreach, int rank)
7669 counter = new StatementExpression[rank];
7670 variables = new TemporaryVariableReference[rank];
7671 length_exprs = new Expression [rank];
7674 // Only use temporary length variables when dealing with
7675 // multi-dimensional arrays
7678 lengths = new TemporaryVariableReference [rank];
7681 public override bool Resolve (BlockContext ec)
7683 Block variables_block = for_each.variable.Block;
7684 copy = TemporaryVariableReference.Create (for_each.expr.Type, variables_block, loc);
7687 int rank = length_exprs.Length;
7688 Arguments list = new Arguments (rank);
7689 for (int i = 0; i < rank; i++) {
7690 var v = TemporaryVariableReference.Create (ec.BuiltinTypes.Int, variables_block, loc);
7692 counter[i] = new StatementExpression (new UnaryMutator (UnaryMutator.Mode.PostIncrement, v, Location.Null));
7693 counter[i].Resolve (ec);
7696 length_exprs [i] = new MemberAccess (copy, "Length").Resolve (ec);
7698 lengths[i] = TemporaryVariableReference.Create (ec.BuiltinTypes.Int, variables_block, loc);
7699 lengths[i].Resolve (ec);
7701 Arguments args = new Arguments (1);
7702 args.Add (new Argument (new IntConstant (ec.BuiltinTypes, i, loc)));
7703 length_exprs [i] = new Invocation (new MemberAccess (copy, "GetLength"), args).Resolve (ec);
7706 list.Add (new Argument (v));
7709 var access = new ElementAccess (copy, list, loc).Resolve (ec);
7714 if (for_each.type is VarExpr) {
7715 // Infer implicitly typed local variable from foreach array type
7716 var_type = access.Type;
7718 var_type = for_each.type.ResolveAsType (ec);
7720 if (var_type == null)
7723 access = Convert.ExplicitConversion (ec, access, var_type, loc);
7728 for_each.variable.Type = var_type;
7730 var variable_ref = new LocalVariableReference (for_each.variable, loc).Resolve (ec);
7731 if (variable_ref == null)
7734 for_each.body.AddScopeStatement (new StatementExpression (new CompilerAssign (variable_ref, access, Location.Null), for_each.type.Location));
7736 return for_each.body.Resolve (ec);
7739 protected override void DoEmit (EmitContext ec)
7741 copy.EmitAssign (ec, for_each.expr);
7743 int rank = length_exprs.Length;
7744 Label[] test = new Label [rank];
7745 Label[] loop = new Label [rank];
7747 for (int i = 0; i < rank; i++) {
7748 test [i] = ec.DefineLabel ();
7749 loop [i] = ec.DefineLabel ();
7751 if (lengths != null)
7752 lengths [i].EmitAssign (ec, length_exprs [i]);
7755 IntConstant zero = new IntConstant (ec.BuiltinTypes, 0, loc);
7756 for (int i = 0; i < rank; i++) {
7757 variables [i].EmitAssign (ec, zero);
7759 ec.Emit (OpCodes.Br, test [i]);
7760 ec.MarkLabel (loop [i]);
7763 for_each.body.Emit (ec);
7765 ec.MarkLabel (ec.LoopBegin);
7766 ec.Mark (for_each.expr.Location);
7768 for (int i = rank - 1; i >= 0; i--){
7769 counter [i].Emit (ec);
7771 ec.MarkLabel (test [i]);
7772 variables [i].Emit (ec);
7774 if (lengths != null)
7775 lengths [i].Emit (ec);
7777 length_exprs [i].Emit (ec);
7779 ec.Emit (OpCodes.Blt, loop [i]);
7782 ec.MarkLabel (ec.LoopEnd);
7786 sealed class CollectionForeach : IteratorStatement, OverloadResolver.IErrorHandler
7788 class RuntimeDispose : Using.VariableDeclaration
7790 public RuntimeDispose (LocalVariable lv, Location loc)
7796 protected override void CheckIDiposableConversion (BlockContext bc, LocalVariable li, Expression initializer)
7798 // Defered to runtime check
7801 protected override Statement CreateDisposeCall (BlockContext bc, LocalVariable lv)
7803 var idt = bc.BuiltinTypes.IDisposable;
7806 // Fabricates code like
7808 // if ((temp = vr as IDisposable) != null) temp.Dispose ();
7811 var dispose_variable = LocalVariable.CreateCompilerGenerated (idt, bc.CurrentBlock, loc);
7813 var idisaposable_test = new Binary (Binary.Operator.Inequality, new CompilerAssign (
7814 dispose_variable.CreateReferenceExpression (bc, loc),
7815 new As (lv.CreateReferenceExpression (bc, loc), new TypeExpression (dispose_variable.Type, loc), loc),
7816 loc), new NullLiteral (loc));
7818 var m = bc.Module.PredefinedMembers.IDisposableDispose.Resolve (loc);
7820 var dispose_mg = MethodGroupExpr.CreatePredefined (m, idt, loc);
7821 dispose_mg.InstanceExpression = dispose_variable.CreateReferenceExpression (bc, loc);
7823 Statement dispose = new StatementExpression (new Invocation (dispose_mg, null));
7824 return new If (idisaposable_test, dispose, loc);
7828 LocalVariable variable;
7830 Statement statement;
7831 ExpressionStatement init;
7832 TemporaryVariableReference enumerator_variable;
7833 bool ambiguous_getenumerator_name;
7835 public CollectionForeach (Foreach @foreach, LocalVariable var, Expression expr)
7838 this.variable = var;
7842 void Error_WrongEnumerator (ResolveContext rc, MethodSpec enumerator)
7844 rc.Report.SymbolRelatedToPreviousError (enumerator);
7845 rc.Report.Error (202, loc,
7846 "foreach statement requires that the return type `{0}' of `{1}' must have a suitable public MoveNext method and public Current property",
7847 enumerator.ReturnType.GetSignatureForError (), enumerator.GetSignatureForError ());
7850 MethodGroupExpr ResolveGetEnumerator (ResolveContext rc)
7853 // Option 1: Try to match by name GetEnumerator first
7855 var mexpr = Expression.MemberLookup (rc, false, expr.Type,
7856 "GetEnumerator", 0, Expression.MemberLookupRestrictions.ExactArity, loc); // TODO: What if CS0229 ?
7858 var mg = mexpr as MethodGroupExpr;
7860 mg.InstanceExpression = expr;
7861 Arguments args = new Arguments (0);
7862 mg = mg.OverloadResolve (rc, ref args, this, OverloadResolver.Restrictions.ProbingOnly | OverloadResolver.Restrictions.GetEnumeratorLookup);
7864 // For ambiguous GetEnumerator name warning CS0278 was reported, but Option 2 could still apply
7865 if (ambiguous_getenumerator_name)
7868 if (mg != null && !mg.BestCandidate.IsStatic && mg.BestCandidate.IsPublic) {
7874 // Option 2: Try to match using IEnumerable interfaces with preference of generic version
7877 PredefinedMember<MethodSpec> iface_candidate = null;
7878 var ptypes = rc.Module.PredefinedTypes;
7879 var gen_ienumerable = ptypes.IEnumerableGeneric;
7880 if (!gen_ienumerable.Define ())
7881 gen_ienumerable = null;
7883 var ifaces = t.Interfaces;
7884 if (ifaces != null) {
7885 foreach (var iface in ifaces) {
7886 if (gen_ienumerable != null && iface.MemberDefinition == gen_ienumerable.TypeSpec.MemberDefinition) {
7887 if (iface_candidate != null && iface_candidate != rc.Module.PredefinedMembers.IEnumerableGetEnumerator) {
7888 rc.Report.SymbolRelatedToPreviousError (expr.Type);
7889 rc.Report.Error (1640, loc,
7890 "foreach statement cannot operate on variables of type `{0}' because it contains multiple implementation of `{1}'. Try casting to a specific implementation",
7891 expr.Type.GetSignatureForError (), gen_ienumerable.TypeSpec.GetSignatureForError ());
7896 // TODO: Cache this somehow
7897 iface_candidate = new PredefinedMember<MethodSpec> (rc.Module, iface,
7898 MemberFilter.Method ("GetEnumerator", 0, ParametersCompiled.EmptyReadOnlyParameters, null));
7903 if (iface.BuiltinType == BuiltinTypeSpec.Type.IEnumerable && iface_candidate == null) {
7904 iface_candidate = rc.Module.PredefinedMembers.IEnumerableGetEnumerator;
7909 if (iface_candidate == null) {
7910 if (expr.Type != InternalType.ErrorType) {
7911 rc.Report.Error (1579, loc,
7912 "foreach statement cannot operate on variables of type `{0}' because it does not contain a definition for `{1}' or is inaccessible",
7913 expr.Type.GetSignatureForError (), "GetEnumerator");
7919 var method = iface_candidate.Resolve (loc);
7923 mg = MethodGroupExpr.CreatePredefined (method, expr.Type, loc);
7924 mg.InstanceExpression = expr;
7928 MethodGroupExpr ResolveMoveNext (ResolveContext rc, MethodSpec enumerator)
7930 var ms = MemberCache.FindMember (enumerator.ReturnType,
7931 MemberFilter.Method ("MoveNext", 0, ParametersCompiled.EmptyReadOnlyParameters, rc.BuiltinTypes.Bool),
7932 BindingRestriction.InstanceOnly) as MethodSpec;
7934 if (ms == null || !ms.IsPublic) {
7935 Error_WrongEnumerator (rc, enumerator);
7939 return MethodGroupExpr.CreatePredefined (ms, enumerator.ReturnType, expr.Location);
7942 PropertySpec ResolveCurrent (ResolveContext rc, MethodSpec enumerator)
7944 var ps = MemberCache.FindMember (enumerator.ReturnType,
7945 MemberFilter.Property ("Current", null),
7946 BindingRestriction.InstanceOnly) as PropertySpec;
7948 if (ps == null || !ps.IsPublic) {
7949 Error_WrongEnumerator (rc, enumerator);
7956 public override bool Resolve (BlockContext ec)
7958 bool is_dynamic = expr.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
7961 expr = Convert.ImplicitConversionRequired (ec, expr, ec.BuiltinTypes.IEnumerable, loc);
7962 } else if (expr.Type.IsNullableType) {
7963 expr = new Nullable.UnwrapCall (expr).Resolve (ec);
7966 var get_enumerator_mg = ResolveGetEnumerator (ec);
7967 if (get_enumerator_mg == null) {
7971 var get_enumerator = get_enumerator_mg.BestCandidate;
7972 enumerator_variable = TemporaryVariableReference.Create (get_enumerator.ReturnType, variable.Block, loc);
7973 enumerator_variable.Resolve (ec);
7975 // Prepare bool MoveNext ()
7976 var move_next_mg = ResolveMoveNext (ec, get_enumerator);
7977 if (move_next_mg == null) {
7981 move_next_mg.InstanceExpression = enumerator_variable;
7983 // Prepare ~T~ Current { get; }
7984 var current_prop = ResolveCurrent (ec, get_enumerator);
7985 if (current_prop == null) {
7989 var current_pe = new PropertyExpr (current_prop, loc) { InstanceExpression = enumerator_variable }.Resolve (ec);
7990 if (current_pe == null)
7993 VarExpr ve = for_each.type as VarExpr;
7997 // Source type is dynamic, set element type to dynamic too
7998 variable.Type = ec.BuiltinTypes.Dynamic;
8000 // Infer implicitly typed local variable from foreach enumerable type
8001 variable.Type = current_pe.Type;
8005 // Explicit cast of dynamic collection elements has to be done at runtime
8006 current_pe = EmptyCast.Create (current_pe, ec.BuiltinTypes.Dynamic);
8009 variable.Type = for_each.type.ResolveAsType (ec);
8011 if (variable.Type == null)
8014 current_pe = Convert.ExplicitConversion (ec, current_pe, variable.Type, loc);
8015 if (current_pe == null)
8019 var variable_ref = new LocalVariableReference (variable, loc).Resolve (ec);
8020 if (variable_ref == null)
8023 for_each.body.AddScopeStatement (new StatementExpression (new CompilerAssign (variable_ref, current_pe, Location.Null), for_each.type.Location));
8025 var init = new Invocation.Predefined (get_enumerator_mg, null);
8027 statement = new While (new BooleanExpression (new Invocation (move_next_mg, null)),
8028 for_each.body, Location.Null);
8030 var enum_type = enumerator_variable.Type;
8033 // Add Dispose method call when enumerator can be IDisposable
8035 if (!enum_type.ImplementsInterface (ec.BuiltinTypes.IDisposable, false)) {
8036 if (!enum_type.IsSealed && !TypeSpec.IsValueType (enum_type)) {
8038 // Runtime Dispose check
8040 var vd = new RuntimeDispose (enumerator_variable.LocalInfo, Location.Null);
8041 vd.Initializer = init;
8042 statement = new Using (vd, statement, Location.Null);
8045 // No Dispose call needed
8047 this.init = new SimpleAssign (enumerator_variable, init, Location.Null);
8048 this.init.Resolve (ec);
8052 // Static Dispose check
8054 var vd = new Using.VariableDeclaration (enumerator_variable.LocalInfo, Location.Null);
8055 vd.Initializer = init;
8056 statement = new Using (vd, statement, Location.Null);
8059 return statement.Resolve (ec);
8062 protected override void DoEmit (EmitContext ec)
8064 enumerator_variable.LocalInfo.CreateBuilder (ec);
8067 init.EmitStatement (ec);
8069 statement.Emit (ec);
8072 #region IErrorHandler Members
8074 bool OverloadResolver.IErrorHandler.AmbiguousCandidates (ResolveContext ec, MemberSpec best, MemberSpec ambiguous)
8076 ec.Report.SymbolRelatedToPreviousError (best);
8077 ec.Report.Warning (278, 2, expr.Location,
8078 "`{0}' contains ambiguous implementation of `{1}' pattern. Method `{2}' is ambiguous with method `{3}'",
8079 expr.Type.GetSignatureForError (), "enumerable",
8080 best.GetSignatureForError (), ambiguous.GetSignatureForError ());
8082 ambiguous_getenumerator_name = true;
8086 bool OverloadResolver.IErrorHandler.ArgumentMismatch (ResolveContext rc, MemberSpec best, Argument arg, int index)
8091 bool OverloadResolver.IErrorHandler.NoArgumentMatch (ResolveContext rc, MemberSpec best)
8096 bool OverloadResolver.IErrorHandler.TypeInferenceFailed (ResolveContext rc, MemberSpec best)
8105 LocalVariable variable;
8109 public Foreach (Expression type, LocalVariable var, Expression expr, Statement stmt, Block body, Location l)
8113 this.variable = var;
8119 public Expression Expr {
8120 get { return expr; }
8123 public Expression TypeExpression {
8124 get { return type; }
8127 public LocalVariable Variable {
8128 get { return variable; }
8131 public override Reachability MarkReachable (Reachability rc)
8133 base.MarkReachable (rc);
8135 body.MarkReachable (rc);
8140 public override bool Resolve (BlockContext ec)
8142 expr = expr.Resolve (ec);
8147 ec.Report.Error (186, loc, "Use of null is not valid in this context");
8151 body.AddStatement (Statement);
8153 if (expr.Type.BuiltinType == BuiltinTypeSpec.Type.String) {
8154 Statement = new ArrayForeach (this, 1);
8155 } else if (expr.Type is ArrayContainer) {
8156 Statement = new ArrayForeach (this, ((ArrayContainer) expr.Type).Rank);
8158 if (expr.eclass == ExprClass.MethodGroup || expr is AnonymousMethodExpression) {
8159 ec.Report.Error (446, expr.Location, "Foreach statement cannot operate on a `{0}'",
8160 expr.ExprClassName);
8164 Statement = new CollectionForeach (this, variable, expr);
8167 return base.Resolve (ec);
8170 protected override void DoEmit (EmitContext ec)
8172 Label old_begin = ec.LoopBegin, old_end = ec.LoopEnd;
8173 ec.LoopBegin = ec.DefineLabel ();
8174 ec.LoopEnd = ec.DefineLabel ();
8176 if (!(Statement is Block))
8177 ec.BeginCompilerScope ();
8179 variable.CreateBuilder (ec);
8181 Statement.Emit (ec);
8183 if (!(Statement is Block))
8186 ec.LoopBegin = old_begin;
8187 ec.LoopEnd = old_end;
8190 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
8192 expr.FlowAnalysis (fc);
8194 var da = fc.BranchDefiniteAssignment ();
8195 body.FlowAnalysis (fc);
8196 fc.DefiniteAssignment = da;
8200 protected override void CloneTo (CloneContext clonectx, Statement t)
8202 Foreach target = (Foreach) t;
8204 target.type = type.Clone (clonectx);
8205 target.expr = expr.Clone (clonectx);
8206 target.body = (Block) body.Clone (clonectx);
8207 target.Statement = Statement.Clone (clonectx);
8210 public override object Accept (StructuralVisitor visitor)
8212 return visitor.Visit (this);
8216 class SentinelStatement: Statement
8218 protected override void CloneTo (CloneContext clonectx, Statement target)
8222 protected override void DoEmit (EmitContext ec)
8224 var l = ec.DefineLabel ();
8226 ec.Emit (OpCodes.Br_S, l);
8229 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
8231 throw new NotImplementedException ();