2 // statement.cs: Statement representation for the IL tree.
5 // Miguel de Icaza (miguel@ximian.com)
6 // Martin Baulig (martin@ximian.com)
7 // Marek Safar (marek.safar@gmail.com)
9 // Copyright 2001, 2002, 2003 Ximian, Inc.
10 // Copyright 2003, 2004 Novell, Inc.
11 // Copyright 2011 Xamarin Inc.
15 using System.Collections.Generic;
18 using IKVM.Reflection.Emit;
20 using System.Reflection.Emit;
23 namespace Mono.CSharp {
25 public abstract class Statement {
27 protected bool reachable;
29 public bool IsUnreachable {
36 /// Resolves the statement, true means that all sub-statements
39 public virtual bool Resolve (BlockContext bc)
45 /// Return value indicates whether all code paths emitted return.
47 protected abstract void DoEmit (EmitContext ec);
49 public virtual void Emit (EmitContext ec)
54 if (ec.StatementEpilogue != null) {
60 // This routine must be overrided in derived classes and make copies
61 // of all the data that might be modified if resolved
63 protected abstract void CloneTo (CloneContext clonectx, Statement target);
65 public Statement Clone (CloneContext clonectx)
67 Statement s = (Statement) this.MemberwiseClone ();
68 CloneTo (clonectx, s);
72 public virtual Expression CreateExpressionTree (ResolveContext ec)
74 ec.Report.Error (834, loc, "A lambda expression with statement body cannot be converted to an expresion tree");
78 public virtual object Accept (StructuralVisitor visitor)
80 return visitor.Visit (this);
84 // Return value indicates whether statement has unreachable end
86 protected abstract bool DoFlowAnalysis (FlowAnalysisContext fc);
88 public bool FlowAnalysis (FlowAnalysisContext fc)
91 fc.UnreachableReported = false;
92 var res = DoFlowAnalysis (fc);
97 // Special handling cases
100 return DoFlowAnalysis (fc);
103 if (this is EmptyStatement || loc.IsNull)
106 if (fc.UnreachableReported)
109 fc.Report.Warning (162, 2, loc, "Unreachable code detected");
110 fc.UnreachableReported = true;
114 public virtual Reachability MarkReachable (Reachability rc)
116 if (!rc.IsUnreachable)
122 protected void CheckExitBoundaries (BlockContext bc, Block scope)
124 if (bc.CurrentBlock.ParametersBlock.Original != scope.ParametersBlock.Original) {
125 bc.Report.Error (1632, loc, "Control cannot leave the body of an anonymous method");
129 for (var b = bc.CurrentBlock; b != null && b != scope; b = b.Parent) {
130 if (b.IsFinallyBlock) {
131 Error_FinallyClauseExit (bc);
137 protected void Error_FinallyClauseExit (BlockContext bc)
139 bc.Report.Error (157, loc, "Control cannot leave the body of a finally clause");
143 public sealed class EmptyStatement : Statement
145 public EmptyStatement (Location loc)
150 public override bool Resolve (BlockContext ec)
155 public override void Emit (EmitContext ec)
159 protected override void DoEmit (EmitContext ec)
161 throw new NotSupportedException ();
164 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
169 protected override void CloneTo (CloneContext clonectx, Statement target)
174 public override object Accept (StructuralVisitor visitor)
176 return visitor.Visit (this);
180 public class If : Statement {
182 public Statement TrueStatement;
183 public Statement FalseStatement;
185 bool true_returns, false_returns;
187 public If (Expression bool_expr, Statement true_statement, Location l)
188 : this (bool_expr, true_statement, null, l)
192 public If (Expression bool_expr,
193 Statement true_statement,
194 Statement false_statement,
197 this.expr = bool_expr;
198 TrueStatement = true_statement;
199 FalseStatement = false_statement;
203 public Expression Expr {
209 public override bool Resolve (BlockContext ec)
211 expr = expr.Resolve (ec);
213 var ok = TrueStatement.Resolve (ec);
215 if (FalseStatement != null) {
216 ok &= FalseStatement.Resolve (ec);
222 protected override void DoEmit (EmitContext ec)
224 Label false_target = ec.DefineLabel ();
228 // If we're a boolean constant, Resolve() already
229 // eliminated dead code for us.
231 Constant c = expr as Constant;
233 c.EmitSideEffect (ec);
235 if (!c.IsDefaultValue)
236 TrueStatement.Emit (ec);
237 else if (FalseStatement != null)
238 FalseStatement.Emit (ec);
243 expr.EmitBranchable (ec, false_target, false);
245 TrueStatement.Emit (ec);
247 if (FalseStatement != null){
248 bool branch_emitted = false;
250 end = ec.DefineLabel ();
252 ec.Emit (OpCodes.Br, end);
253 branch_emitted = true;
256 ec.MarkLabel (false_target);
257 FalseStatement.Emit (ec);
262 ec.MarkLabel (false_target);
266 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
268 expr.FlowAnalysisConditional (fc);
270 var da_false = new DefiniteAssignmentBitSet (fc.DefiniteAssignmentOnFalse);
272 fc.DefiniteAssignment = fc.DefiniteAssignmentOnTrue;
274 var res = TrueStatement.FlowAnalysis (fc);
276 if (FalseStatement == null) {
277 var c = expr as Constant;
278 if (c != null && !c.IsDefaultValue)
282 fc.DefiniteAssignment = da_false;
284 fc.DefiniteAssignment &= da_false;
290 fc.DefiniteAssignment = da_false;
291 return FalseStatement.FlowAnalysis (fc);
294 var da_true = fc.DefiniteAssignment;
296 fc.DefiniteAssignment = da_false;
297 res &= FalseStatement.FlowAnalysis (fc);
299 if (!TrueStatement.IsUnreachable) {
300 if (false_returns || FalseStatement.IsUnreachable)
301 fc.DefiniteAssignment = da_true;
303 fc.DefiniteAssignment &= da_true;
309 public override Reachability MarkReachable (Reachability rc)
311 if (rc.IsUnreachable)
314 base.MarkReachable (rc);
316 var c = expr as Constant;
318 bool take = !c.IsDefaultValue;
320 rc = TrueStatement.MarkReachable (rc);
322 if (FalseStatement != null)
323 rc = FalseStatement.MarkReachable (rc);
329 var true_rc = TrueStatement.MarkReachable (rc);
330 true_returns = true_rc.IsUnreachable;
332 if (FalseStatement == null)
335 var false_rc = FalseStatement.MarkReachable (rc);
336 false_returns = false_rc.IsUnreachable;
338 return true_rc & false_rc;
341 protected override void CloneTo (CloneContext clonectx, Statement t)
345 target.expr = expr.Clone (clonectx);
346 target.TrueStatement = TrueStatement.Clone (clonectx);
347 if (FalseStatement != null)
348 target.FalseStatement = FalseStatement.Clone (clonectx);
351 public override object Accept (StructuralVisitor visitor)
353 return visitor.Visit (this);
357 public class Do : LoopStatement
359 public Expression expr;
360 bool iterator_reachable, end_reachable;
362 public Do (Statement statement, BooleanExpression bool_expr, Location doLocation, Location whileLocation)
367 WhileLocation = whileLocation;
370 public Location WhileLocation {
374 public override bool Resolve (BlockContext bc)
376 var ok = base.Resolve (bc);
378 expr = expr.Resolve (bc);
383 protected override void DoEmit (EmitContext ec)
385 Label loop = ec.DefineLabel ();
386 Label old_begin = ec.LoopBegin;
387 Label old_end = ec.LoopEnd;
389 ec.LoopBegin = ec.DefineLabel ();
390 ec.LoopEnd = ec.DefineLabel ();
394 ec.MarkLabel (ec.LoopBegin);
396 // Mark start of while condition
397 ec.Mark (WhileLocation);
400 // Dead code elimination
402 if (expr is Constant) {
403 bool res = !((Constant) expr).IsDefaultValue;
405 expr.EmitSideEffect (ec);
407 ec.Emit (OpCodes.Br, loop);
409 expr.EmitBranchable (ec, loop, true);
412 ec.MarkLabel (ec.LoopEnd);
414 ec.LoopBegin = old_begin;
415 ec.LoopEnd = old_end;
418 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
420 var res = Statement.FlowAnalysis (fc);
422 expr.FlowAnalysisConditional (fc);
424 fc.DefiniteAssignment = fc.DefiniteAssignmentOnFalse;
426 if (res && !iterator_reachable)
427 return !end_reachable;
429 if (!end_reachable) {
430 var c = expr as Constant;
431 if (c != null && !c.IsDefaultValue)
438 public override Reachability MarkReachable (Reachability rc)
440 base.MarkReachable (rc);
442 var body_rc = Statement.MarkReachable (rc);
444 if (body_rc.IsUnreachable && !iterator_reachable) {
445 expr = new UnreachableExpression (expr);
446 return end_reachable ? rc : Reachability.CreateUnreachable ();
449 if (!end_reachable) {
450 var c = expr as Constant;
451 if (c != null && !c.IsDefaultValue)
452 return Reachability.CreateUnreachable ();
458 protected override void CloneTo (CloneContext clonectx, Statement t)
462 target.Statement = Statement.Clone (clonectx);
463 target.expr = expr.Clone (clonectx);
466 public override object Accept (StructuralVisitor visitor)
468 return visitor.Visit (this);
471 public override void SetEndReachable ()
473 end_reachable = true;
476 public override void SetIteratorReachable ()
478 iterator_reachable = true;
482 public class While : LoopStatement
484 public Expression expr;
485 bool empty, infinite, end_reachable;
486 List<DefiniteAssignmentBitSet> end_reachable_das;
488 public While (BooleanExpression bool_expr, Statement statement, Location l)
491 this.expr = bool_expr;
495 public override bool Resolve (BlockContext bc)
499 expr = expr.Resolve (bc);
503 var c = expr as Constant;
505 empty = c.IsDefaultValue;
509 ok &= base.Resolve (bc);
513 protected override void DoEmit (EmitContext ec)
516 expr.EmitSideEffect (ec);
520 Label old_begin = ec.LoopBegin;
521 Label old_end = ec.LoopEnd;
523 ec.LoopBegin = ec.DefineLabel ();
524 ec.LoopEnd = ec.DefineLabel ();
527 // Inform whether we are infinite or not
529 if (expr is Constant) {
530 // expr is 'true', since the 'empty' case above handles the 'false' case
531 ec.MarkLabel (ec.LoopBegin);
533 if (ec.EmitAccurateDebugInfo)
534 ec.Emit (OpCodes.Nop);
536 expr.EmitSideEffect (ec);
538 ec.Emit (OpCodes.Br, ec.LoopBegin);
541 // Inform that we are infinite (ie, `we return'), only
542 // if we do not `break' inside the code.
544 ec.MarkLabel (ec.LoopEnd);
546 Label while_loop = ec.DefineLabel ();
548 ec.Emit (OpCodes.Br, ec.LoopBegin);
549 ec.MarkLabel (while_loop);
553 ec.MarkLabel (ec.LoopBegin);
556 expr.EmitBranchable (ec, while_loop, true);
558 ec.MarkLabel (ec.LoopEnd);
561 ec.LoopBegin = old_begin;
562 ec.LoopEnd = old_end;
565 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
567 expr.FlowAnalysisConditional (fc);
569 fc.DefiniteAssignment = fc.DefiniteAssignmentOnTrue;
570 var da_false = new DefiniteAssignmentBitSet (fc.DefiniteAssignmentOnFalse);
572 Statement.FlowAnalysis (fc);
575 // Special case infinite while with breaks
577 if (end_reachable_das != null) {
578 da_false = DefiniteAssignmentBitSet.And (end_reachable_das);
579 end_reachable_das = null;
582 fc.DefiniteAssignment = da_false;
584 if (infinite && !end_reachable)
590 public override Reachability MarkReachable (Reachability rc)
592 if (rc.IsUnreachable)
595 base.MarkReachable (rc);
598 // Special case unreachable while body
601 Statement.MarkReachable (Reachability.CreateUnreachable ());
605 Statement.MarkReachable (rc);
608 // When infinite while end is unreachable via break anything what follows is unreachable too
610 if (infinite && !end_reachable)
611 return Reachability.CreateUnreachable ();
616 protected override void CloneTo (CloneContext clonectx, Statement t)
618 While target = (While) t;
620 target.expr = expr.Clone (clonectx);
621 target.Statement = Statement.Clone (clonectx);
624 public override object Accept (StructuralVisitor visitor)
626 return visitor.Visit (this);
629 public override void AddEndDefiniteAssignment (FlowAnalysisContext fc)
634 if (end_reachable_das == null)
635 end_reachable_das = new List<DefiniteAssignmentBitSet> ();
637 end_reachable_das.Add (fc.DefiniteAssignment);
640 public override void SetEndReachable ()
642 end_reachable = true;
646 public class For : LoopStatement
648 bool infinite, empty, iterator_reachable, end_reachable;
649 List<DefiniteAssignmentBitSet> end_reachable_das;
651 public For (Location l)
657 public Statement Initializer {
661 public Expression Condition {
665 public Statement Iterator {
669 public override bool Resolve (BlockContext bc)
671 Initializer.Resolve (bc);
673 if (Condition != null) {
674 Condition = Condition.Resolve (bc);
675 var condition_constant = Condition as Constant;
676 if (condition_constant != null) {
677 if (condition_constant.IsDefaultValue) {
687 return base.Resolve (bc) && Iterator.Resolve (bc);
690 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
692 Initializer.FlowAnalysis (fc);
694 DefiniteAssignmentBitSet da_false;
695 if (Condition != null) {
696 Condition.FlowAnalysisConditional (fc);
697 fc.DefiniteAssignment = fc.DefiniteAssignmentOnTrue;
698 da_false = new DefiniteAssignmentBitSet (fc.DefiniteAssignmentOnFalse);
700 da_false = fc.BranchDefiniteAssignment ();
703 Statement.FlowAnalysis (fc);
705 Iterator.FlowAnalysis (fc);
708 // Special case infinite for with breaks
710 if (end_reachable_das != null) {
711 da_false = DefiniteAssignmentBitSet.And (end_reachable_das);
712 end_reachable_das = null;
715 fc.DefiniteAssignment = da_false;
717 if (infinite && !end_reachable)
723 public override Reachability MarkReachable (Reachability rc)
725 base.MarkReachable (rc);
727 Initializer.MarkReachable (rc);
729 var body_rc = Statement.MarkReachable (rc);
730 if (!body_rc.IsUnreachable || iterator_reachable) {
731 Iterator.MarkReachable (rc);
735 // When infinite for end is unreachable via break anything what follows is unreachable too
737 if (infinite && !end_reachable) {
738 return Reachability.CreateUnreachable ();
744 protected override void DoEmit (EmitContext ec)
746 if (Initializer != null)
747 Initializer.Emit (ec);
750 Condition.EmitSideEffect (ec);
754 Label old_begin = ec.LoopBegin;
755 Label old_end = ec.LoopEnd;
756 Label loop = ec.DefineLabel ();
757 Label test = ec.DefineLabel ();
759 ec.LoopBegin = ec.DefineLabel ();
760 ec.LoopEnd = ec.DefineLabel ();
762 ec.Emit (OpCodes.Br, test);
766 ec.MarkLabel (ec.LoopBegin);
771 // If test is null, there is no test, and we are just
774 if (Condition != null) {
775 ec.Mark (Condition.Location);
778 // The Resolve code already catches the case for
779 // Test == Constant (false) so we know that
782 if (Condition is Constant) {
783 Condition.EmitSideEffect (ec);
784 ec.Emit (OpCodes.Br, loop);
786 Condition.EmitBranchable (ec, loop, true);
790 ec.Emit (OpCodes.Br, loop);
791 ec.MarkLabel (ec.LoopEnd);
793 ec.LoopBegin = old_begin;
794 ec.LoopEnd = old_end;
797 protected override void CloneTo (CloneContext clonectx, Statement t)
799 For target = (For) t;
801 if (Initializer != null)
802 target.Initializer = Initializer.Clone (clonectx);
803 if (Condition != null)
804 target.Condition = Condition.Clone (clonectx);
805 if (Iterator != null)
806 target.Iterator = Iterator.Clone (clonectx);
807 target.Statement = Statement.Clone (clonectx);
810 public override object Accept (StructuralVisitor visitor)
812 return visitor.Visit (this);
815 public override void AddEndDefiniteAssignment (FlowAnalysisContext fc)
820 if (end_reachable_das == null)
821 end_reachable_das = new List<DefiniteAssignmentBitSet> ();
823 end_reachable_das.Add (fc.DefiniteAssignment);
826 public override void SetEndReachable ()
828 end_reachable = true;
831 public override void SetIteratorReachable ()
833 iterator_reachable = true;
837 public abstract class LoopStatement : Statement
839 protected LoopStatement (Statement statement)
841 Statement = statement;
844 public Statement Statement { get; set; }
846 public override bool Resolve (BlockContext bc)
848 var prev_loop = bc.EnclosingLoop;
849 var prev_los = bc.EnclosingLoopOrSwitch;
850 bc.EnclosingLoopOrSwitch = bc.EnclosingLoop = this;
851 var ok = Statement.Resolve (bc);
852 bc.EnclosingLoopOrSwitch = prev_los;
853 bc.EnclosingLoop = prev_loop;
859 // Needed by possibly infinite loops statements (for, while) and switch statment
861 public virtual void AddEndDefiniteAssignment (FlowAnalysisContext fc)
865 public virtual void SetEndReachable ()
869 public virtual void SetIteratorReachable ()
874 public class StatementExpression : Statement
876 ExpressionStatement expr;
878 public StatementExpression (ExpressionStatement expr)
881 loc = expr.StartLocation;
884 public StatementExpression (ExpressionStatement expr, Location loc)
890 public ExpressionStatement Expr {
896 protected override void CloneTo (CloneContext clonectx, Statement t)
898 StatementExpression target = (StatementExpression) t;
899 target.expr = (ExpressionStatement) expr.Clone (clonectx);
902 protected override void DoEmit (EmitContext ec)
904 expr.EmitStatement (ec);
907 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
909 expr.FlowAnalysis (fc);
913 public override Reachability MarkReachable (Reachability rc)
915 base.MarkReachable (rc);
916 expr.MarkReachable (rc);
920 public override bool Resolve (BlockContext ec)
922 expr = expr.ResolveStatement (ec);
926 public override object Accept (StructuralVisitor visitor)
928 return visitor.Visit (this);
932 public class StatementErrorExpression : Statement
936 public StatementErrorExpression (Expression expr)
939 this.loc = expr.StartLocation;
942 public Expression Expr {
948 public override bool Resolve (BlockContext bc)
950 expr.Error_InvalidExpressionStatement (bc);
954 protected override void DoEmit (EmitContext ec)
956 throw new NotSupportedException ();
959 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
964 protected override void CloneTo (CloneContext clonectx, Statement target)
966 var t = (StatementErrorExpression) target;
968 t.expr = expr.Clone (clonectx);
971 public override object Accept (StructuralVisitor visitor)
973 return visitor.Visit (this);
978 // Simple version of statement list not requiring a block
980 public class StatementList : Statement
982 List<Statement> statements;
984 public StatementList (Statement first, Statement second)
986 statements = new List<Statement> { first, second };
990 public IList<Statement> Statements {
997 public void Add (Statement statement)
999 statements.Add (statement);
1002 public override bool Resolve (BlockContext ec)
1004 foreach (var s in statements)
1010 protected override void DoEmit (EmitContext ec)
1012 foreach (var s in statements)
1016 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1018 foreach (var s in statements)
1019 s.FlowAnalysis (fc);
1024 public override Reachability MarkReachable (Reachability rc)
1026 base.MarkReachable (rc);
1028 Reachability res = rc;
1029 foreach (var s in statements)
1030 res = s.MarkReachable (rc);
1035 protected override void CloneTo (CloneContext clonectx, Statement target)
1037 StatementList t = (StatementList) target;
1039 t.statements = new List<Statement> (statements.Count);
1040 foreach (Statement s in statements)
1041 t.statements.Add (s.Clone (clonectx));
1044 public override object Accept (StructuralVisitor visitor)
1046 return visitor.Visit (this);
1051 // For statements which require special handling when inside try or catch block
1053 public abstract class ExitStatement : Statement
1055 protected bool unwind_protect;
1057 protected abstract bool DoResolve (BlockContext bc);
1058 protected abstract bool IsLocalExit { get; }
1060 public override bool Resolve (BlockContext bc)
1062 var res = DoResolve (bc);
1066 // We are inside finally scope but is it the scope we are exiting
1068 if (bc.HasSet (ResolveContext.Options.FinallyScope)) {
1070 for (var b = bc.CurrentBlock; b != null; b = b.Parent) {
1071 if (b.IsFinallyBlock) {
1072 Error_FinallyClauseExit (bc);
1076 if (b is ParametersBlock)
1082 unwind_protect = bc.HasAny (ResolveContext.Options.TryScope | ResolveContext.Options.CatchScope);
1086 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1091 if (fc.TryFinally != null) {
1092 fc.TryFinally.RegisterForControlExitCheck (new DefiniteAssignmentBitSet (fc.DefiniteAssignment));
1094 fc.ParametersBlock.CheckControlExit (fc);
1102 /// Implements the return statement
1104 public class Return : ExitStatement
1108 public Return (Expression expr, Location l)
1116 public Expression Expr {
1125 protected override bool IsLocalExit {
1133 protected override bool DoResolve (BlockContext ec)
1135 var block_return_type = ec.ReturnType;
1138 if (block_return_type.Kind == MemberKind.Void)
1142 // Return must not be followed by an expression when
1143 // the method return type is Task
1145 if (ec.CurrentAnonymousMethod is AsyncInitializer) {
1146 var storey = (AsyncTaskStorey) ec.CurrentAnonymousMethod.Storey;
1147 if (storey.ReturnType == ec.Module.PredefinedTypes.Task.TypeSpec) {
1149 // Extra trick not to emit ret/leave inside awaiter body
1151 expr = EmptyExpression.Null;
1155 if (storey.ReturnType.IsGenericTask)
1156 block_return_type = storey.ReturnType.TypeArguments[0];
1159 if (ec.CurrentIterator != null) {
1160 Error_ReturnFromIterator (ec);
1161 } else if (block_return_type != InternalType.ErrorType) {
1162 ec.Report.Error (126, loc,
1163 "An object of a type convertible to `{0}' is required for the return statement",
1164 block_return_type.GetSignatureForError ());
1170 expr = expr.Resolve (ec);
1172 AnonymousExpression am = ec.CurrentAnonymousMethod;
1174 if (block_return_type.Kind == MemberKind.Void) {
1175 ec.Report.Error (127, loc,
1176 "`{0}': A return keyword must not be followed by any expression when method returns void",
1177 ec.GetSignatureForError ());
1182 if (am.IsIterator) {
1183 Error_ReturnFromIterator (ec);
1187 var async_block = am as AsyncInitializer;
1188 if (async_block != null) {
1190 var storey = (AsyncTaskStorey) am.Storey;
1191 var async_type = storey.ReturnType;
1193 if (async_type == null && async_block.ReturnTypeInference != null) {
1194 if (expr.Type.Kind == MemberKind.Void && !(this is ContextualReturn))
1195 ec.Report.Error (4029, loc, "Cannot return an expression of type `void'");
1197 async_block.ReturnTypeInference.AddCommonTypeBoundAsync (expr.Type);
1201 if (async_type.Kind == MemberKind.Void) {
1202 ec.Report.Error (8030, loc,
1203 "Anonymous function or lambda expression converted to a void returning delegate cannot return a value");
1207 if (!async_type.IsGenericTask) {
1208 if (this is ContextualReturn)
1211 if (async_block.DelegateType != null) {
1212 ec.Report.Error (8031, loc,
1213 "Async lambda expression or anonymous method converted to a `Task' cannot return a value. Consider returning `Task<T>'");
1215 ec.Report.Error (1997, loc,
1216 "`{0}': A return keyword must not be followed by an expression when async method returns `Task'. Consider using `Task<T>' return type",
1217 ec.GetSignatureForError ());
1223 // The return type is actually Task<T> type argument
1225 if (expr.Type == async_type) {
1226 ec.Report.Error (4016, loc,
1227 "`{0}': The return expression type of async method must be `{1}' rather than `Task<{1}>'",
1228 ec.GetSignatureForError (), async_type.TypeArguments[0].GetSignatureForError ());
1230 block_return_type = async_type.TypeArguments[0];
1234 if (block_return_type.Kind == MemberKind.Void) {
1235 ec.Report.Error (8030, loc,
1236 "Anonymous function or lambda expression converted to a void returning delegate cannot return a value");
1240 var l = am as AnonymousMethodBody;
1241 if (l != null && expr != null) {
1242 if (l.ReturnTypeInference != null) {
1243 l.ReturnTypeInference.AddCommonTypeBound (expr.Type);
1248 // Try to optimize simple lambda. Only when optimizations are enabled not to cause
1249 // unexpected debugging experience
1251 if (this is ContextualReturn && !ec.IsInProbingMode && ec.Module.Compiler.Settings.Optimize) {
1252 l.DirectMethodGroupConversion = expr.CanReduceLambda (l);
1261 if (expr.Type != block_return_type && expr.Type != InternalType.ErrorType) {
1262 expr = Convert.ImplicitConversionRequired (ec, expr, block_return_type, loc);
1265 if (am != null && block_return_type == ec.ReturnType) {
1266 ec.Report.Error (1662, loc,
1267 "Cannot convert `{0}' to delegate type `{1}' because some of the return types in the block are not implicitly convertible to the delegate return type",
1268 am.ContainerType, am.GetSignatureForError ());
1277 protected override void DoEmit (EmitContext ec)
1281 var async_body = ec.CurrentAnonymousMethod as AsyncInitializer;
1282 if (async_body != null) {
1283 var storey = (AsyncTaskStorey)async_body.Storey;
1284 Label exit_label = async_body.BodyEnd;
1287 // It's null for await without async
1289 if (storey.HoistedReturnValue != null) {
1291 // Special case hoisted return value (happens in try/finally scenario)
1293 if (ec.TryFinallyUnwind != null) {
1294 if (storey.HoistedReturnValue is VariableReference) {
1295 storey.HoistedReturnValue = ec.GetTemporaryField (storey.HoistedReturnValue.Type);
1298 exit_label = TryFinally.EmitRedirectedReturn (ec, async_body);
1301 var async_return = (IAssignMethod)storey.HoistedReturnValue;
1302 async_return.EmitAssign (ec, expr, false, false);
1307 if (ec.TryFinallyUnwind != null)
1308 exit_label = TryFinally.EmitRedirectedReturn (ec, async_body);
1311 ec.Emit (OpCodes.Leave, exit_label);
1318 if (unwind_protect || ec.EmitAccurateDebugInfo)
1319 ec.Emit (OpCodes.Stloc, ec.TemporaryReturn ());
1322 if (unwind_protect) {
1323 ec.Emit (OpCodes.Leave, ec.CreateReturnLabel ());
1324 } else if (ec.EmitAccurateDebugInfo) {
1325 ec.Emit (OpCodes.Br, ec.CreateReturnLabel ());
1327 ec.Emit (OpCodes.Ret);
1331 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1334 expr.FlowAnalysis (fc);
1336 base.DoFlowAnalysis (fc);
1340 void Error_ReturnFromIterator (ResolveContext rc)
1342 rc.Report.Error (1622, loc,
1343 "Cannot return a value from iterators. Use the yield return statement to return a value, or yield break to end the iteration");
1346 public override Reachability MarkReachable (Reachability rc)
1348 base.MarkReachable (rc);
1349 return Reachability.CreateUnreachable ();
1352 protected override void CloneTo (CloneContext clonectx, Statement t)
1354 Return target = (Return) t;
1355 // It's null for simple return;
1357 target.expr = expr.Clone (clonectx);
1360 public override object Accept (StructuralVisitor visitor)
1362 return visitor.Visit (this);
1366 public class Goto : ExitStatement
1369 LabeledStatement label;
1370 TryFinally try_finally;
1372 public Goto (string label, Location l)
1378 public string Target {
1379 get { return target; }
1382 protected override bool IsLocalExit {
1388 protected override bool DoResolve (BlockContext bc)
1390 label = bc.CurrentBlock.LookupLabel (target);
1391 if (label == null) {
1392 Error_UnknownLabel (bc, target, loc);
1396 try_finally = bc.CurrentTryBlock as TryFinally;
1398 CheckExitBoundaries (bc, label.Block);
1403 public static void Error_UnknownLabel (BlockContext bc, string label, Location loc)
1405 bc.Report.Error (159, loc, "The label `{0}:' could not be found within the scope of the goto statement",
1409 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1411 if (fc.LabelStack == null) {
1412 fc.LabelStack = new List<LabeledStatement> ();
1413 } else if (fc.LabelStack.Contains (label)) {
1417 fc.LabelStack.Add (label);
1418 label.Block.ScanGotoJump (label, fc);
1419 fc.LabelStack.Remove (label);
1423 public override Reachability MarkReachable (Reachability rc)
1425 if (rc.IsUnreachable)
1428 base.MarkReachable (rc);
1430 if (try_finally != null) {
1431 if (try_finally.FinallyBlock.HasReachableClosingBrace) {
1432 label.AddGotoReference (rc, false);
1434 label.AddGotoReference (rc, true);
1437 label.AddGotoReference (rc, false);
1440 return Reachability.CreateUnreachable ();
1443 protected override void CloneTo (CloneContext clonectx, Statement target)
1448 protected override void DoEmit (EmitContext ec)
1451 throw new InternalErrorException ("goto emitted before target resolved");
1453 Label l = label.LabelTarget (ec);
1455 if (ec.TryFinallyUnwind != null && IsLeavingFinally (label.Block)) {
1456 var async_body = (AsyncInitializer) ec.CurrentAnonymousMethod;
1457 l = TryFinally.EmitRedirectedJump (ec, async_body, l, label.Block);
1460 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, l);
1463 bool IsLeavingFinally (Block labelBlock)
1465 var b = try_finally.Statement as Block;
1467 if (b == labelBlock)
1476 public override object Accept (StructuralVisitor visitor)
1478 return visitor.Visit (this);
1482 public class LabeledStatement : Statement {
1490 public LabeledStatement (string name, Block block, Location l)
1497 public Label LabelTarget (EmitContext ec)
1502 label = ec.DefineLabel ();
1507 public Block Block {
1513 public string Name {
1514 get { return name; }
1517 protected override void CloneTo (CloneContext clonectx, Statement target)
1519 var t = (LabeledStatement) target;
1521 t.block = clonectx.RemapBlockCopy (block);
1524 public override bool Resolve (BlockContext bc)
1529 protected override void DoEmit (EmitContext ec)
1532 ec.MarkLabel (label);
1535 ec.Emit (OpCodes.Br_S, label);
1538 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1541 fc.Report.Warning (164, 2, loc, "This label has not been referenced");
1547 public override Reachability MarkReachable (Reachability rc)
1549 base.MarkReachable (rc);
1552 rc = new Reachability ();
1557 public void AddGotoReference (Reachability rc, bool finalTarget)
1566 // Label is final target when goto jumps out of try block with
1567 // finally clause. In that case we need leave with target but in C#
1568 // terms the label is unreachable. Using finalTarget we emit
1569 // explicit label not just marker
1572 this.finalTarget = true;
1576 block.ScanGotoJump (this);
1579 public override object Accept (StructuralVisitor visitor)
1581 return visitor.Visit (this);
1587 /// `goto default' statement
1589 public class GotoDefault : SwitchGoto
1591 public GotoDefault (Location l)
1596 public override bool Resolve (BlockContext bc)
1598 if (bc.Switch == null) {
1599 Error_GotoCaseRequiresSwitchBlock (bc);
1603 bc.Switch.RegisterGotoCase (null, null);
1609 protected override void DoEmit (EmitContext ec)
1611 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, ec.Switch.DefaultLabel.GetILLabel (ec));
1614 public override Reachability MarkReachable (Reachability rc)
1616 if (!rc.IsUnreachable) {
1617 var label = switch_statement.DefaultLabel;
1618 if (label.IsUnreachable) {
1619 label.MarkReachable (rc);
1620 switch_statement.Block.ScanGotoJump (label);
1624 return base.MarkReachable (rc);
1627 public override object Accept (StructuralVisitor visitor)
1629 return visitor.Visit (this);
1634 /// `goto case' statement
1636 public class GotoCase : SwitchGoto
1640 public GotoCase (Expression e, Location l)
1646 public Expression Expr {
1652 public SwitchLabel Label { get; set; }
1654 public override bool Resolve (BlockContext ec)
1656 if (ec.Switch == null) {
1657 Error_GotoCaseRequiresSwitchBlock (ec);
1661 Constant c = expr.ResolveLabelConstant (ec);
1667 if (ec.Switch.IsNullable && c is NullLiteral) {
1670 TypeSpec type = ec.Switch.SwitchType;
1671 res = c.Reduce (ec, type);
1673 c.Error_ValueCannotBeConverted (ec, type, true);
1677 if (!Convert.ImplicitStandardConversionExists (c, type))
1678 ec.Report.Warning (469, 2, loc,
1679 "The `goto case' value is not implicitly convertible to type `{0}'",
1680 type.GetSignatureForError ());
1684 ec.Switch.RegisterGotoCase (this, res);
1691 protected override void DoEmit (EmitContext ec)
1693 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, Label.GetILLabel (ec));
1696 protected override void CloneTo (CloneContext clonectx, Statement t)
1698 GotoCase target = (GotoCase) t;
1700 target.expr = expr.Clone (clonectx);
1703 public override Reachability MarkReachable (Reachability rc)
1705 if (!rc.IsUnreachable) {
1706 var label = switch_statement.FindLabel ((Constant) expr);
1707 if (label.IsUnreachable) {
1708 label.MarkReachable (rc);
1709 switch_statement.Block.ScanGotoJump (label);
1713 return base.MarkReachable (rc);
1716 public override object Accept (StructuralVisitor visitor)
1718 return visitor.Visit (this);
1722 public abstract class SwitchGoto : Statement
1724 protected bool unwind_protect;
1725 protected Switch switch_statement;
1727 protected SwitchGoto (Location loc)
1732 protected override void CloneTo (CloneContext clonectx, Statement target)
1737 public override bool Resolve (BlockContext bc)
1739 CheckExitBoundaries (bc, bc.Switch.Block);
1741 unwind_protect = bc.HasAny (ResolveContext.Options.TryScope | ResolveContext.Options.CatchScope);
1742 switch_statement = bc.Switch;
1747 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1752 public override Reachability MarkReachable (Reachability rc)
1754 base.MarkReachable (rc);
1755 return Reachability.CreateUnreachable ();
1758 protected void Error_GotoCaseRequiresSwitchBlock (BlockContext bc)
1760 bc.Report.Error (153, loc, "A goto case is only valid inside a switch statement");
1764 public class Throw : Statement {
1767 public Throw (Expression expr, Location l)
1773 public Expression Expr {
1779 public override bool Resolve (BlockContext ec)
1782 if (!ec.HasSet (ResolveContext.Options.CatchScope)) {
1783 ec.Report.Error (156, loc, "A throw statement with no arguments is not allowed outside of a catch clause");
1784 } else if (ec.HasSet (ResolveContext.Options.FinallyScope)) {
1785 for (var b = ec.CurrentBlock; b != null && !b.IsCatchBlock; b = b.Parent) {
1786 if (b.IsFinallyBlock) {
1787 ec.Report.Error (724, loc,
1788 "A throw statement with no arguments is not allowed inside of a finally clause nested inside of the innermost catch clause");
1797 expr = expr.Resolve (ec, ResolveFlags.Type | ResolveFlags.VariableOrValue);
1802 var et = ec.BuiltinTypes.Exception;
1803 if (Convert.ImplicitConversionExists (ec, expr, et))
1804 expr = Convert.ImplicitConversion (ec, expr, et, loc);
1806 ec.Report.Error (155, expr.Location, "The type caught or thrown must be derived from System.Exception");
1811 protected override void DoEmit (EmitContext ec)
1814 var atv = ec.AsyncThrowVariable;
1816 if (atv.HoistedVariant != null) {
1817 atv.HoistedVariant.Emit (ec);
1822 ec.Emit (OpCodes.Throw);
1824 ec.Emit (OpCodes.Rethrow);
1829 ec.Emit (OpCodes.Throw);
1833 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1836 expr.FlowAnalysis (fc);
1841 public override Reachability MarkReachable (Reachability rc)
1843 base.MarkReachable (rc);
1844 return Reachability.CreateUnreachable ();
1847 protected override void CloneTo (CloneContext clonectx, Statement t)
1849 Throw target = (Throw) t;
1852 target.expr = expr.Clone (clonectx);
1855 public override object Accept (StructuralVisitor visitor)
1857 return visitor.Visit (this);
1861 public class Break : LocalExitStatement
1863 public Break (Location l)
1868 public override object Accept (StructuralVisitor visitor)
1870 return visitor.Visit (this);
1873 protected override void DoEmit (EmitContext ec)
1877 if (ec.TryFinallyUnwind != null) {
1878 var async_body = (AsyncInitializer) ec.CurrentAnonymousMethod;
1879 l = TryFinally.EmitRedirectedJump (ec, async_body, l, enclosing_loop.Statement as Block);
1882 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, l);
1885 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
1887 enclosing_loop.AddEndDefiniteAssignment (fc);
1891 protected override bool DoResolve (BlockContext bc)
1893 enclosing_loop = bc.EnclosingLoopOrSwitch;
1894 return base.DoResolve (bc);
1897 public override Reachability MarkReachable (Reachability rc)
1899 base.MarkReachable (rc);
1901 if (!rc.IsUnreachable)
1902 enclosing_loop.SetEndReachable ();
1904 return Reachability.CreateUnreachable ();
1908 public class Continue : LocalExitStatement
1910 public Continue (Location l)
1915 public override object Accept (StructuralVisitor visitor)
1917 return visitor.Visit (this);
1921 protected override void DoEmit (EmitContext ec)
1923 var l = ec.LoopBegin;
1925 if (ec.TryFinallyUnwind != null) {
1926 var async_body = (AsyncInitializer) ec.CurrentAnonymousMethod;
1927 l = TryFinally.EmitRedirectedJump (ec, async_body, l, enclosing_loop.Statement as Block);
1930 ec.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, l);
1933 protected override bool DoResolve (BlockContext bc)
1935 enclosing_loop = bc.EnclosingLoop;
1936 return base.DoResolve (bc);
1939 public override Reachability MarkReachable (Reachability rc)
1941 base.MarkReachable (rc);
1943 if (!rc.IsUnreachable)
1944 enclosing_loop.SetIteratorReachable ();
1946 return Reachability.CreateUnreachable ();
1950 public abstract class LocalExitStatement : ExitStatement
1952 protected LoopStatement enclosing_loop;
1954 protected LocalExitStatement (Location loc)
1959 protected override bool IsLocalExit {
1965 protected override void CloneTo (CloneContext clonectx, Statement t)
1970 protected override bool DoResolve (BlockContext bc)
1972 if (enclosing_loop == null) {
1973 bc.Report.Error (139, loc, "No enclosing loop out of which to break or continue");
1977 var block = enclosing_loop.Statement as Block;
1979 // Don't need to do extra checks for simple statements loops
1980 if (block != null) {
1981 CheckExitBoundaries (bc, block);
1988 public interface ILocalVariable
1990 void Emit (EmitContext ec);
1991 void EmitAssign (EmitContext ec);
1992 void EmitAddressOf (EmitContext ec);
1995 public interface INamedBlockVariable
1997 Block Block { get; }
1998 Expression CreateReferenceExpression (ResolveContext rc, Location loc);
1999 bool IsDeclared { get; }
2000 bool IsParameter { get; }
2001 Location Location { get; }
2004 public class BlockVariableDeclarator
2007 Expression initializer;
2009 public BlockVariableDeclarator (LocalVariable li, Expression initializer)
2011 if (li.Type != null)
2012 throw new ArgumentException ("Expected null variable type");
2015 this.initializer = initializer;
2020 public LocalVariable Variable {
2026 public Expression Initializer {
2031 initializer = value;
2037 public virtual BlockVariableDeclarator Clone (CloneContext cloneCtx)
2039 var t = (BlockVariableDeclarator) MemberwiseClone ();
2040 if (initializer != null)
2041 t.initializer = initializer.Clone (cloneCtx);
2047 public class BlockVariable : Statement
2049 Expression initializer;
2050 protected FullNamedExpression type_expr;
2051 protected LocalVariable li;
2052 protected List<BlockVariableDeclarator> declarators;
2055 public BlockVariable (FullNamedExpression type, LocalVariable li)
2057 this.type_expr = type;
2059 this.loc = type_expr.Location;
2062 protected BlockVariable (LocalVariable li)
2069 public List<BlockVariableDeclarator> Declarators {
2075 public Expression Initializer {
2080 initializer = value;
2084 public FullNamedExpression TypeExpression {
2090 public LocalVariable Variable {
2098 public void AddDeclarator (BlockVariableDeclarator decl)
2100 if (declarators == null)
2101 declarators = new List<BlockVariableDeclarator> ();
2103 declarators.Add (decl);
2106 static void CreateEvaluatorVariable (BlockContext bc, LocalVariable li)
2108 if (bc.Report.Errors != 0)
2111 var container = bc.CurrentMemberDefinition.Parent.PartialContainer;
2113 Field f = new Field (container, new TypeExpression (li.Type, li.Location), Modifiers.PUBLIC | Modifiers.STATIC,
2114 new MemberName (li.Name, li.Location), null);
2116 container.AddField (f);
2119 li.HoistedVariant = new HoistedEvaluatorVariable (f);
2123 public override bool Resolve (BlockContext bc)
2125 return Resolve (bc, true);
2128 public bool Resolve (BlockContext bc, bool resolveDeclaratorInitializers)
2130 if (type == null && !li.IsCompilerGenerated) {
2131 var vexpr = type_expr as VarExpr;
2134 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
2135 // same name exists or as a keyword when no type was found
2137 if (vexpr != null && !vexpr.IsPossibleTypeOrNamespace (bc)) {
2138 if (bc.Module.Compiler.Settings.Version < LanguageVersion.V_3)
2139 bc.Report.FeatureIsNotAvailable (bc.Module.Compiler, loc, "implicitly typed local variable");
2142 bc.Report.Error (821, loc, "A fixed statement cannot use an implicitly typed local variable");
2146 if (li.IsConstant) {
2147 bc.Report.Error (822, loc, "An implicitly typed local variable cannot be a constant");
2151 if (Initializer == null) {
2152 bc.Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
2156 if (declarators != null) {
2157 bc.Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
2161 Initializer = Initializer.Resolve (bc);
2162 if (Initializer != null) {
2163 ((VarExpr) type_expr).InferType (bc, Initializer);
2164 type = type_expr.Type;
2166 // Set error type to indicate the var was placed correctly but could
2169 // var a = missing ();
2171 type = InternalType.ErrorType;
2176 type = type_expr.ResolveAsType (bc);
2180 if (li.IsConstant && !type.IsConstantCompatible) {
2181 Const.Error_InvalidConstantType (type, loc, bc.Report);
2186 FieldBase.Error_VariableOfStaticClass (loc, li.Name, type, bc.Report);
2191 bool eval_global = bc.Module.Compiler.Settings.StatementMode && bc.CurrentBlock is ToplevelBlock;
2193 CreateEvaluatorVariable (bc, li);
2194 } else if (type != InternalType.ErrorType) {
2195 li.PrepareAssignmentAnalysis (bc);
2198 if (initializer != null) {
2199 initializer = ResolveInitializer (bc, li, initializer);
2200 // li.Variable.DefinitelyAssigned
2203 if (declarators != null) {
2204 foreach (var d in declarators) {
2205 d.Variable.Type = li.Type;
2207 CreateEvaluatorVariable (bc, d.Variable);
2208 } else if (type != InternalType.ErrorType) {
2209 d.Variable.PrepareAssignmentAnalysis (bc);
2212 if (d.Initializer != null && resolveDeclaratorInitializers) {
2213 d.Initializer = ResolveInitializer (bc, d.Variable, d.Initializer);
2214 // d.Variable.DefinitelyAssigned
2222 protected virtual Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
2224 var a = new SimpleAssign (li.CreateReferenceExpression (bc, li.Location), initializer, li.Location);
2225 return a.ResolveStatement (bc);
2228 protected override void DoEmit (EmitContext ec)
2230 li.CreateBuilder (ec);
2232 if (Initializer != null && !IsUnreachable)
2233 ((ExpressionStatement) Initializer).EmitStatement (ec);
2235 if (declarators != null) {
2236 foreach (var d in declarators) {
2237 d.Variable.CreateBuilder (ec);
2238 if (d.Initializer != null && !IsUnreachable) {
2239 ec.Mark (d.Variable.Location);
2240 ((ExpressionStatement) d.Initializer).EmitStatement (ec);
2246 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
2248 if (Initializer != null)
2249 Initializer.FlowAnalysis (fc);
2251 if (declarators != null) {
2252 foreach (var d in declarators) {
2253 if (d.Initializer != null)
2254 d.Initializer.FlowAnalysis (fc);
2261 public override Reachability MarkReachable (Reachability rc)
2263 var init = initializer as ExpressionStatement;
2265 init.MarkReachable (rc);
2267 return base.MarkReachable (rc);
2270 protected override void CloneTo (CloneContext clonectx, Statement target)
2272 BlockVariable t = (BlockVariable) target;
2274 if (type_expr != null)
2275 t.type_expr = (FullNamedExpression) type_expr.Clone (clonectx);
2277 if (initializer != null)
2278 t.initializer = initializer.Clone (clonectx);
2280 if (declarators != null) {
2281 t.declarators = null;
2282 foreach (var d in declarators)
2283 t.AddDeclarator (d.Clone (clonectx));
2287 public override object Accept (StructuralVisitor visitor)
2289 return visitor.Visit (this);
2293 public class BlockConstant : BlockVariable
2295 public BlockConstant (FullNamedExpression type, LocalVariable li)
2300 public override void Emit (EmitContext ec)
2302 // Nothing to emit, not even sequence point
2305 protected override Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
2307 initializer = initializer.Resolve (bc);
2308 if (initializer == null)
2311 var c = initializer as Constant;
2313 initializer.Error_ExpressionMustBeConstant (bc, initializer.Location, li.Name);
2317 c = c.ConvertImplicitly (li.Type);
2319 if (TypeSpec.IsReferenceType (li.Type))
2320 initializer.Error_ConstantCanBeInitializedWithNullOnly (bc, li.Type, initializer.Location, li.Name);
2322 initializer.Error_ValueCannotBeConverted (bc, li.Type, false);
2327 li.ConstantValue = c;
2331 public override object Accept (StructuralVisitor visitor)
2333 return visitor.Visit (this);
2338 // The information about a user-perceived local variable
2340 public sealed class LocalVariable : INamedBlockVariable, ILocalVariable
2347 AddressTaken = 1 << 2,
2348 CompilerGenerated = 1 << 3,
2350 ForeachVariable = 1 << 5,
2351 FixedVariable = 1 << 6,
2352 UsingVariable = 1 << 7,
2355 ReadonlyMask = ForeachVariable | FixedVariable | UsingVariable
2359 readonly string name;
2360 readonly Location loc;
2361 readonly Block block;
2363 Constant const_value;
2365 public VariableInfo VariableInfo;
2366 HoistedVariable hoisted_variant;
2368 LocalBuilder builder;
2370 public LocalVariable (Block block, string name, Location loc)
2377 public LocalVariable (Block block, string name, Flags flags, Location loc)
2378 : this (block, name, loc)
2384 // Used by variable declarators
2386 public LocalVariable (LocalVariable li, string name, Location loc)
2387 : this (li.block, name, li.flags, loc)
2393 public bool AddressTaken {
2395 return (flags & Flags.AddressTaken) != 0;
2399 public Block Block {
2405 public Constant ConstantValue {
2410 const_value = value;
2415 // Hoisted local variable variant
2417 public HoistedVariable HoistedVariant {
2419 return hoisted_variant;
2422 hoisted_variant = value;
2426 public bool IsDeclared {
2428 return type != null;
2432 public bool IsCompilerGenerated {
2434 return (flags & Flags.CompilerGenerated) != 0;
2438 public bool IsConstant {
2440 return (flags & Flags.Constant) != 0;
2444 public bool IsLocked {
2446 return (flags & Flags.IsLocked) != 0;
2449 flags = value ? flags | Flags.IsLocked : flags & ~Flags.IsLocked;
2453 public bool IsThis {
2455 return (flags & Flags.IsThis) != 0;
2459 public bool IsFixed {
2461 return (flags & Flags.FixedVariable) != 0;
2465 bool INamedBlockVariable.IsParameter {
2471 public bool IsReadonly {
2473 return (flags & Flags.ReadonlyMask) != 0;
2477 public Location Location {
2483 public string Name {
2489 public TypeSpec Type {
2500 public void CreateBuilder (EmitContext ec)
2502 if ((flags & Flags.Used) == 0) {
2503 if (VariableInfo == null) {
2504 // Missing flow analysis or wrong variable flags
2505 throw new InternalErrorException ("VariableInfo is null and the variable `{0}' is not used", name);
2508 if (VariableInfo.IsEverAssigned)
2509 ec.Report.Warning (219, 3, Location, "The variable `{0}' is assigned but its value is never used", Name);
2511 ec.Report.Warning (168, 3, Location, "The variable `{0}' is declared but never used", Name);
2514 if (HoistedVariant != null)
2517 if (builder != null) {
2518 if ((flags & Flags.CompilerGenerated) != 0)
2521 // To avoid Used warning duplicates
2522 throw new InternalErrorException ("Already created variable `{0}'", name);
2526 // All fixed variabled are pinned, a slot has to be alocated
2528 builder = ec.DeclareLocal (Type, IsFixed);
2529 if (!ec.HasSet (BuilderContext.Options.OmitDebugInfo) && (flags & Flags.CompilerGenerated) == 0)
2530 ec.DefineLocalVariable (name, builder);
2533 public static LocalVariable CreateCompilerGenerated (TypeSpec type, Block block, Location loc)
2535 LocalVariable li = new LocalVariable (block, GetCompilerGeneratedName (block), Flags.CompilerGenerated | Flags.Used, loc);
2540 public Expression CreateReferenceExpression (ResolveContext rc, Location loc)
2542 if (IsConstant && const_value != null)
2543 return Constant.CreateConstantFromValue (Type, const_value.GetValue (), loc);
2545 return new LocalVariableReference (this, loc);
2548 public void Emit (EmitContext ec)
2550 // TODO: Need something better for temporary variables
2551 if ((flags & Flags.CompilerGenerated) != 0)
2554 ec.Emit (OpCodes.Ldloc, builder);
2557 public void EmitAssign (EmitContext ec)
2559 // TODO: Need something better for temporary variables
2560 if ((flags & Flags.CompilerGenerated) != 0)
2563 ec.Emit (OpCodes.Stloc, builder);
2566 public void EmitAddressOf (EmitContext ec)
2568 // TODO: Need something better for temporary variables
2569 if ((flags & Flags.CompilerGenerated) != 0)
2572 ec.Emit (OpCodes.Ldloca, builder);
2575 public static string GetCompilerGeneratedName (Block block)
2577 // HACK: Debugger depends on the name semantics
2578 return "$locvar" + block.ParametersBlock.TemporaryLocalsCount++.ToString ("X");
2581 public string GetReadOnlyContext ()
2583 switch (flags & Flags.ReadonlyMask) {
2584 case Flags.FixedVariable:
2585 return "fixed variable";
2586 case Flags.ForeachVariable:
2587 return "foreach iteration variable";
2588 case Flags.UsingVariable:
2589 return "using variable";
2592 throw new InternalErrorException ("Variable is not readonly");
2595 public bool IsThisAssigned (FlowAnalysisContext fc, Block block)
2597 if (VariableInfo == null)
2598 throw new Exception ();
2600 if (IsAssigned (fc))
2603 return VariableInfo.IsFullyInitialized (fc, block.StartLocation);
2606 public bool IsAssigned (FlowAnalysisContext fc)
2608 return fc.IsDefinitelyAssigned (VariableInfo);
2611 public void PrepareAssignmentAnalysis (BlockContext bc)
2614 // No need to run assignment analysis for these guys
2616 if ((flags & (Flags.Constant | Flags.ReadonlyMask | Flags.CompilerGenerated)) != 0)
2619 VariableInfo = VariableInfo.Create (bc, this);
2623 // Mark the variables as referenced in the user code
2625 public void SetIsUsed ()
2627 flags |= Flags.Used;
2630 public void SetHasAddressTaken ()
2632 flags |= (Flags.AddressTaken | Flags.Used);
2635 public override string ToString ()
2637 return string.Format ("LocalInfo ({0},{1},{2},{3})", name, type, VariableInfo, Location);
2642 /// Block represents a C# block.
2646 /// This class is used in a number of places: either to represent
2647 /// explicit blocks that the programmer places or implicit blocks.
2649 /// Implicit blocks are used as labels or to introduce variable
2652 /// Top-level blocks derive from Block, and they are called ToplevelBlock
2653 /// they contain extra information that is not necessary on normal blocks.
2655 public class Block : Statement {
2662 HasCapturedVariable = 64,
2663 HasCapturedThis = 1 << 7,
2664 IsExpressionTree = 1 << 8,
2665 CompilerGenerated = 1 << 9,
2666 HasAsyncModifier = 1 << 10,
2668 YieldBlock = 1 << 12,
2669 AwaitBlock = 1 << 13,
2670 FinallyBlock = 1 << 14,
2671 CatchBlock = 1 << 15,
2673 NoFlowAnalysis = 1 << 21,
2674 InitializationEmitted = 1 << 22
2677 public Block Parent;
2678 public Location StartLocation;
2679 public Location EndLocation;
2681 public ExplicitBlock Explicit;
2682 public ParametersBlock ParametersBlock;
2684 protected Flags flags;
2687 // The statements in this block
2689 protected List<Statement> statements;
2691 protected List<Statement> scope_initializers;
2693 int? resolving_init_idx;
2699 public int ID = id++;
2701 static int clone_id_counter;
2705 // int assignable_slots;
2707 public Block (Block parent, Location start, Location end)
2708 : this (parent, 0, start, end)
2712 public Block (Block parent, Flags flags, Location start, Location end)
2714 if (parent != null) {
2715 // the appropriate constructors will fixup these fields
2716 ParametersBlock = parent.ParametersBlock;
2717 Explicit = parent.Explicit;
2720 this.Parent = parent;
2722 this.StartLocation = start;
2723 this.EndLocation = end;
2725 statements = new List<Statement> (4);
2727 this.original = this;
2732 public Block Original {
2741 public bool IsCompilerGenerated {
2742 get { return (flags & Flags.CompilerGenerated) != 0; }
2743 set { flags = value ? flags | Flags.CompilerGenerated : flags & ~Flags.CompilerGenerated; }
2747 public bool IsCatchBlock {
2749 return (flags & Flags.CatchBlock) != 0;
2753 public bool IsFinallyBlock {
2755 return (flags & Flags.FinallyBlock) != 0;
2759 public bool Unchecked {
2760 get { return (flags & Flags.Unchecked) != 0; }
2761 set { flags = value ? flags | Flags.Unchecked : flags & ~Flags.Unchecked; }
2764 public bool Unsafe {
2765 get { return (flags & Flags.Unsafe) != 0; }
2766 set { flags |= Flags.Unsafe; }
2769 public List<Statement> Statements {
2770 get { return statements; }
2775 public void SetEndLocation (Location loc)
2780 public void AddLabel (LabeledStatement target)
2782 ParametersBlock.TopBlock.AddLabel (target.Name, target);
2785 public void AddLocalName (LocalVariable li)
2787 AddLocalName (li.Name, li);
2790 public void AddLocalName (string name, INamedBlockVariable li)
2792 ParametersBlock.TopBlock.AddLocalName (name, li, false);
2795 public virtual void Error_AlreadyDeclared (string name, INamedBlockVariable variable, string reason)
2797 if (reason == null) {
2798 Error_AlreadyDeclared (name, variable);
2802 ParametersBlock.TopBlock.Report.Error (136, variable.Location,
2803 "A local variable named `{0}' cannot be declared in this scope because it would give a different meaning " +
2804 "to `{0}', which is already used in a `{1}' scope to denote something else",
2808 public virtual void Error_AlreadyDeclared (string name, INamedBlockVariable variable)
2810 var pi = variable as ParametersBlock.ParameterInfo;
2812 pi.Parameter.Error_DuplicateName (ParametersBlock.TopBlock.Report);
2814 ParametersBlock.TopBlock.Report.Error (128, variable.Location,
2815 "A local variable named `{0}' is already defined in this scope", name);
2819 public virtual void Error_AlreadyDeclaredTypeParameter (string name, Location loc)
2821 ParametersBlock.TopBlock.Report.Error (412, loc,
2822 "The type parameter name `{0}' is the same as local variable or parameter name",
2827 // It should be used by expressions which require to
2828 // register a statement during resolve process.
2830 public void AddScopeStatement (Statement s)
2832 if (scope_initializers == null)
2833 scope_initializers = new List<Statement> ();
2836 // Simple recursive helper, when resolve scope initializer another
2837 // new scope initializer can be added, this ensures it's initialized
2838 // before existing one. For now this can happen with expression trees
2839 // in base ctor initializer only
2841 if (resolving_init_idx.HasValue) {
2842 scope_initializers.Insert (resolving_init_idx.Value, s);
2843 ++resolving_init_idx;
2845 scope_initializers.Add (s);
2849 public void InsertStatement (int index, Statement s)
2851 statements.Insert (index, s);
2854 public void AddStatement (Statement s)
2859 public LabeledStatement LookupLabel (string name)
2861 return ParametersBlock.GetLabel (name, this);
2864 public override Reachability MarkReachable (Reachability rc)
2866 if (rc.IsUnreachable)
2869 MarkReachableScope (rc);
2871 foreach (var s in statements) {
2872 rc = s.MarkReachable (rc);
2873 if (rc.IsUnreachable) {
2874 if ((flags & Flags.ReachableEnd) != 0)
2875 return new Reachability ();
2881 flags |= Flags.ReachableEnd;
2886 public void MarkReachableScope (Reachability rc)
2888 base.MarkReachable (rc);
2890 if (scope_initializers != null) {
2891 foreach (var si in scope_initializers)
2892 si.MarkReachable (rc);
2896 public override bool Resolve (BlockContext bc)
2898 if ((flags & Flags.Resolved) != 0)
2901 Block prev_block = bc.CurrentBlock;
2902 bc.CurrentBlock = this;
2905 // Compiler generated scope statements
2907 if (scope_initializers != null) {
2908 for (resolving_init_idx = 0; resolving_init_idx < scope_initializers.Count; ++resolving_init_idx) {
2909 scope_initializers[resolving_init_idx.Value].Resolve (bc);
2912 resolving_init_idx = null;
2916 int statement_count = statements.Count;
2917 for (int ix = 0; ix < statement_count; ix++){
2918 Statement s = statements [ix];
2920 if (!s.Resolve (bc)) {
2922 if (!bc.IsInProbingMode)
2923 statements [ix] = new EmptyStatement (s.loc);
2929 bc.CurrentBlock = prev_block;
2931 flags |= Flags.Resolved;
2935 protected override void DoEmit (EmitContext ec)
2937 for (int ix = 0; ix < statements.Count; ix++){
2938 statements [ix].Emit (ec);
2942 public override void Emit (EmitContext ec)
2944 if (scope_initializers != null)
2945 EmitScopeInitializers (ec);
2950 protected void EmitScopeInitializers (EmitContext ec)
2952 foreach (Statement s in scope_initializers)
2956 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
2958 if (scope_initializers != null) {
2959 foreach (var si in scope_initializers)
2960 si.FlowAnalysis (fc);
2963 return DoFlowAnalysis (fc, 0);
2966 bool DoFlowAnalysis (FlowAnalysisContext fc, int startIndex)
2968 bool end_unreachable = !reachable;
2969 for (; startIndex < statements.Count; ++startIndex) {
2970 var s = statements[startIndex];
2972 end_unreachable = s.FlowAnalysis (fc);
2973 if (s.IsUnreachable) {
2974 statements [startIndex] = RewriteUnreachableStatement (s);
2979 // Statement end reachability is needed mostly due to goto support. Consider
2988 // X label is reachable only via goto not as another statement after if. We need
2989 // this for flow-analysis only to carry variable info correctly.
2991 if (end_unreachable) {
2992 for (++startIndex; startIndex < statements.Count; ++startIndex) {
2993 s = statements[startIndex];
2994 if (s is SwitchLabel) {
2995 s.FlowAnalysis (fc);
2999 if (s.IsUnreachable) {
3000 s.FlowAnalysis (fc);
3001 statements [startIndex] = RewriteUnreachableStatement (s);
3008 // The condition should be true unless there is forward jumping goto
3010 // if (this is ExplicitBlock && end_unreachable != Explicit.HasReachableClosingBrace)
3013 return !Explicit.HasReachableClosingBrace;
3016 static Statement RewriteUnreachableStatement (Statement s)
3018 // LAMESPEC: It's not clear whether declararion statement should be part of reachability
3019 // analysis. Even csc report unreachable warning for it but it's actually used hence
3020 // we try to emulate this behaviour
3028 if (s is BlockVariable)
3031 return new EmptyStatement (s.loc);
3034 public void ScanGotoJump (Statement label)
3037 for (i = 0; i < statements.Count; ++i) {
3038 if (statements[i] == label)
3042 var rc = new Reachability ();
3043 for (++i; i < statements.Count; ++i) {
3044 var s = statements[i];
3045 rc = s.MarkReachable (rc);
3046 if (rc.IsUnreachable)
3050 flags |= Flags.ReachableEnd;
3053 public void ScanGotoJump (Statement label, FlowAnalysisContext fc)
3056 for (i = 0; i < statements.Count; ++i) {
3057 if (statements[i] == label)
3061 DoFlowAnalysis (fc, ++i);
3065 public override string ToString ()
3067 return String.Format ("{0}: ID={1} Clone={2} Location={3}", GetType (), ID, clone_id != 0, StartLocation);
3071 protected override void CloneTo (CloneContext clonectx, Statement t)
3073 Block target = (Block) t;
3075 target.clone_id = ++clone_id_counter;
3078 clonectx.AddBlockMap (this, target);
3079 if (original != this)
3080 clonectx.AddBlockMap (original, target);
3082 target.ParametersBlock = (ParametersBlock) (ParametersBlock == this ? target : clonectx.RemapBlockCopy (ParametersBlock));
3083 target.Explicit = (ExplicitBlock) (Explicit == this ? target : clonectx.LookupBlock (Explicit));
3086 target.Parent = clonectx.RemapBlockCopy (Parent);
3088 target.statements = new List<Statement> (statements.Count);
3089 foreach (Statement s in statements)
3090 target.statements.Add (s.Clone (clonectx));
3093 public override object Accept (StructuralVisitor visitor)
3095 return visitor.Visit (this);
3099 public class ExplicitBlock : Block
3101 protected AnonymousMethodStorey am_storey;
3103 public ExplicitBlock (Block parent, Location start, Location end)
3104 : this (parent, (Flags) 0, start, end)
3108 public ExplicitBlock (Block parent, Flags flags, Location start, Location end)
3109 : base (parent, flags, start, end)
3111 this.Explicit = this;
3116 public AnonymousMethodStorey AnonymousMethodStorey {
3122 public bool HasAwait {
3124 return (flags & Flags.AwaitBlock) != 0;
3128 public bool HasCapturedThis {
3130 flags = value ? flags | Flags.HasCapturedThis : flags & ~Flags.HasCapturedThis;
3133 return (flags & Flags.HasCapturedThis) != 0;
3138 // Used to indicate that the block has reference to parent
3139 // block and cannot be made static when defining anonymous method
3141 public bool HasCapturedVariable {
3143 flags = value ? flags | Flags.HasCapturedVariable : flags & ~Flags.HasCapturedVariable;
3146 return (flags & Flags.HasCapturedVariable) != 0;
3150 public bool HasReachableClosingBrace {
3152 return (flags & Flags.ReachableEnd) != 0;
3155 flags = value ? flags | Flags.ReachableEnd : flags & ~Flags.ReachableEnd;
3159 public bool HasYield {
3161 return (flags & Flags.YieldBlock) != 0;
3168 // Creates anonymous method storey in current block
3170 public AnonymousMethodStorey CreateAnonymousMethodStorey (ResolveContext ec)
3173 // Return same story for iterator and async blocks unless we are
3174 // in nested anonymous method
3176 if (ec.CurrentAnonymousMethod is StateMachineInitializer && ParametersBlock.Original == ec.CurrentAnonymousMethod.Block.Original)
3177 return ec.CurrentAnonymousMethod.Storey;
3179 if (am_storey == null) {
3180 MemberBase mc = ec.MemberContext as MemberBase;
3183 // Creates anonymous method storey for this block
3185 am_storey = new AnonymousMethodStorey (this, ec.CurrentMemberDefinition.Parent.PartialContainer, mc, ec.CurrentTypeParameters, "AnonStorey", MemberKind.Class);
3191 public void EmitScopeInitialization (EmitContext ec)
3193 if ((flags & Flags.InitializationEmitted) != 0)
3196 if (am_storey != null) {
3197 DefineStoreyContainer (ec, am_storey);
3198 am_storey.EmitStoreyInstantiation (ec, this);
3201 if (scope_initializers != null)
3202 EmitScopeInitializers (ec);
3204 flags |= Flags.InitializationEmitted;
3207 public override void Emit (EmitContext ec)
3209 EmitScopeInitialization (ec);
3211 if (ec.EmitAccurateDebugInfo && !IsCompilerGenerated && ec.Mark (StartLocation)) {
3212 ec.Emit (OpCodes.Nop);
3223 if (ec.EmitAccurateDebugInfo && HasReachableClosingBrace && !(this is ParametersBlock) &&
3224 !IsCompilerGenerated && ec.Mark (EndLocation)) {
3225 ec.Emit (OpCodes.Nop);
3229 protected void DefineStoreyContainer (EmitContext ec, AnonymousMethodStorey storey)
3231 if (ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.Storey != null) {
3232 storey.SetNestedStoryParent (ec.CurrentAnonymousMethod.Storey);
3233 storey.Mutator = ec.CurrentAnonymousMethod.Storey.Mutator;
3237 // Creates anonymous method storey
3239 storey.CreateContainer ();
3240 storey.DefineContainer ();
3242 if (Original.Explicit.HasCapturedThis && Original.ParametersBlock.TopBlock.ThisReferencesFromChildrenBlock != null) {
3245 // Only first storey in path will hold this reference. All children blocks will
3246 // reference it indirectly using $ref field
3248 for (Block b = Original.Explicit; b != null; b = b.Parent) {
3249 if (b.Parent != null) {
3250 var s = b.Parent.Explicit.AnonymousMethodStorey;
3252 storey.HoistedThis = s.HoistedThis;
3257 if (b.Explicit == b.Explicit.ParametersBlock && b.Explicit.ParametersBlock.StateMachine != null) {
3258 if (storey.HoistedThis == null)
3259 storey.HoistedThis = b.Explicit.ParametersBlock.StateMachine.HoistedThis;
3261 if (storey.HoistedThis != null)
3267 // We are the first storey on path and 'this' has to be hoisted
3269 if (storey.HoistedThis == null) {
3270 foreach (ExplicitBlock ref_block in Original.ParametersBlock.TopBlock.ThisReferencesFromChildrenBlock) {
3272 // ThisReferencesFromChildrenBlock holds all reference even if they
3273 // are not on this path. It saves some memory otherwise it'd have to
3274 // be in every explicit block. We run this check to see if the reference
3275 // is valid for this storey
3277 Block block_on_path = ref_block;
3278 for (; block_on_path != null && block_on_path != Original; block_on_path = block_on_path.Parent);
3280 if (block_on_path == null)
3283 if (storey.HoistedThis == null) {
3284 storey.AddCapturedThisField (ec, null);
3287 for (ExplicitBlock b = ref_block; b.AnonymousMethodStorey != storey; b = b.Parent.Explicit) {
3289 AnonymousMethodStorey b_storey = b.AnonymousMethodStorey;
3291 if (b_storey != null) {
3293 // Don't add storey cross reference for `this' when the storey ends up not
3294 // beeing attached to any parent
3296 if (b.ParametersBlock.StateMachine == null) {
3297 AnonymousMethodStorey s = null;
3298 for (Block ab = b.AnonymousMethodStorey.OriginalSourceBlock.Parent; ab != null; ab = ab.Parent) {
3299 s = ab.Explicit.AnonymousMethodStorey;
3304 // Needs to be in sync with AnonymousMethodBody::DoCreateMethodHost
3306 var parent = storey == null || storey.Kind == MemberKind.Struct ? null : storey;
3307 b.AnonymousMethodStorey.AddCapturedThisField (ec, parent);
3314 // Stop propagation inside same top block
3316 if (b.ParametersBlock == ParametersBlock.Original) {
3317 b_storey.AddParentStoreyReference (ec, storey);
3318 // b_storey.HoistedThis = storey.HoistedThis;
3322 b = pb = b.ParametersBlock;
3324 pb = b as ParametersBlock;
3327 if (pb != null && pb.StateMachine != null) {
3328 if (pb.StateMachine == storey)
3332 // If we are state machine with no parent. We can hook into parent without additional
3333 // reference and capture this directly
3335 ExplicitBlock parent_storey_block = pb;
3336 while (parent_storey_block.Parent != null) {
3337 parent_storey_block = parent_storey_block.Parent.Explicit;
3338 if (parent_storey_block.AnonymousMethodStorey != null) {
3343 if (parent_storey_block.AnonymousMethodStorey == null) {
3344 pb.StateMachine.AddCapturedThisField (ec, null);
3345 b.HasCapturedThis = true;
3349 pb.StateMachine.AddParentStoreyReference (ec, storey);
3353 // Add parent storey reference only when this is not captured directly
3355 if (b_storey != null) {
3356 b_storey.AddParentStoreyReference (ec, storey);
3357 b_storey.HoistedThis = storey.HoistedThis;
3364 var ref_blocks = storey.ReferencesFromChildrenBlock;
3365 if (ref_blocks != null) {
3366 foreach (ExplicitBlock ref_block in ref_blocks) {
3367 for (ExplicitBlock b = ref_block; b.AnonymousMethodStorey != storey; b = b.Parent.Explicit) {
3368 if (b.AnonymousMethodStorey != null) {
3369 b.AnonymousMethodStorey.AddParentStoreyReference (ec, storey);
3372 // Stop propagation inside same top block
3374 if (b.ParametersBlock == ParametersBlock.Original)
3377 b = b.ParametersBlock;
3380 var pb = b as ParametersBlock;
3381 if (pb != null && pb.StateMachine != null) {
3382 if (pb.StateMachine == storey)
3385 pb.StateMachine.AddParentStoreyReference (ec, storey);
3388 b.HasCapturedVariable = true;
3394 storey.PrepareEmit ();
3395 storey.Parent.PartialContainer.AddCompilerGeneratedClass (storey);
3398 public void RegisterAsyncAwait ()
3401 while ((block.flags & Flags.AwaitBlock) == 0) {
3402 block.flags |= Flags.AwaitBlock;
3404 if (block is ParametersBlock)
3407 block = block.Parent.Explicit;
3411 public void RegisterIteratorYield ()
3413 ParametersBlock.TopBlock.IsIterator = true;
3416 while ((block.flags & Flags.YieldBlock) == 0) {
3417 block.flags |= Flags.YieldBlock;
3419 if (block.Parent == null)
3422 block = block.Parent.Explicit;
3426 public void SetCatchBlock ()
3428 flags |= Flags.CatchBlock;
3431 public void SetFinallyBlock ()
3433 flags |= Flags.FinallyBlock;
3436 public void WrapIntoDestructor (TryFinally tf, ExplicitBlock tryBlock)
3438 tryBlock.statements = statements;
3439 statements = new List<Statement> (1);
3440 statements.Add (tf);
3445 // ParametersBlock was introduced to support anonymous methods
3446 // and lambda expressions
3448 public class ParametersBlock : ExplicitBlock
3450 public class ParameterInfo : INamedBlockVariable
3452 readonly ParametersBlock block;
3454 public VariableInfo VariableInfo;
3457 public ParameterInfo (ParametersBlock block, int index)
3465 public ParametersBlock Block {
3471 Block INamedBlockVariable.Block {
3477 public bool IsDeclared {
3483 public bool IsParameter {
3489 public bool IsLocked {
3498 public Location Location {
3500 return Parameter.Location;
3504 public Parameter Parameter {
3506 return block.Parameters [index];
3510 public TypeSpec ParameterType {
3512 return Parameter.Type;
3518 public Expression CreateReferenceExpression (ResolveContext rc, Location loc)
3520 return new ParameterReference (this, loc);
3525 // Block is converted into an expression
3527 sealed class BlockScopeExpression : Expression
3530 readonly ParametersBlock block;
3532 public BlockScopeExpression (Expression child, ParametersBlock block)
3538 public override bool ContainsEmitWithAwait ()
3540 return child.ContainsEmitWithAwait ();
3543 public override Expression CreateExpressionTree (ResolveContext ec)
3545 throw new NotSupportedException ();
3548 protected override Expression DoResolve (ResolveContext ec)
3553 child = child.Resolve (ec);
3557 eclass = child.eclass;
3562 public override void Emit (EmitContext ec)
3564 block.EmitScopeInitializers (ec);
3569 protected ParametersCompiled parameters;
3570 protected ParameterInfo[] parameter_info;
3571 protected bool resolved;
3572 protected ToplevelBlock top_block;
3573 protected StateMachine state_machine;
3574 protected Dictionary<string, object> labels;
3576 public ParametersBlock (Block parent, ParametersCompiled parameters, Location start, Flags flags = 0)
3577 : base (parent, 0, start, start)
3579 if (parameters == null)
3580 throw new ArgumentNullException ("parameters");
3582 this.parameters = parameters;
3583 ParametersBlock = this;
3585 this.flags |= flags | (parent.ParametersBlock.flags & (Flags.YieldBlock | Flags.AwaitBlock));
3587 this.top_block = parent.ParametersBlock.top_block;
3588 ProcessParameters ();
3591 protected ParametersBlock (ParametersCompiled parameters, Location start)
3592 : base (null, 0, start, start)
3594 if (parameters == null)
3595 throw new ArgumentNullException ("parameters");
3597 this.parameters = parameters;
3598 ParametersBlock = this;
3602 // It's supposed to be used by method body implementation of anonymous methods
3604 protected ParametersBlock (ParametersBlock source, ParametersCompiled parameters)
3605 : base (null, 0, source.StartLocation, source.EndLocation)
3607 this.parameters = parameters;
3608 this.statements = source.statements;
3609 this.scope_initializers = source.scope_initializers;
3611 this.resolved = true;
3612 this.reachable = source.reachable;
3613 this.am_storey = source.am_storey;
3614 this.state_machine = source.state_machine;
3615 this.flags = source.flags & Flags.ReachableEnd;
3617 ParametersBlock = this;
3620 // Overwrite original for comparison purposes when linking cross references
3621 // between anonymous methods
3623 Original = source.Original;
3628 public bool IsAsync {
3630 return (flags & Flags.HasAsyncModifier) != 0;
3633 flags = value ? flags | Flags.HasAsyncModifier : flags & ~Flags.HasAsyncModifier;
3638 // Block has been converted to expression tree
3640 public bool IsExpressionTree {
3642 return (flags & Flags.IsExpressionTree) != 0;
3647 // The parameters for the block.
3649 public ParametersCompiled Parameters {
3655 public StateMachine StateMachine {
3657 return state_machine;
3661 public ToplevelBlock TopBlock {
3670 public bool Resolved {
3672 return (flags & Flags.Resolved) != 0;
3676 public int TemporaryLocalsCount { get; set; }
3681 // Checks whether all `out' parameters have been assigned.
3683 public void CheckControlExit (FlowAnalysisContext fc)
3685 CheckControlExit (fc, fc.DefiniteAssignment);
3688 public virtual void CheckControlExit (FlowAnalysisContext fc, DefiniteAssignmentBitSet dat)
3690 if (parameter_info == null)
3693 foreach (var p in parameter_info) {
3694 if (p.VariableInfo == null)
3697 if (p.VariableInfo.IsAssigned (dat))
3700 fc.Report.Error (177, p.Location,
3701 "The out parameter `{0}' must be assigned to before control leaves the current method",
3706 protected override void CloneTo (CloneContext clonectx, Statement t)
3708 base.CloneTo (clonectx, t);
3710 var target = (ParametersBlock) t;
3713 // Clone label statements as well as they contain block reference
3717 if (pb.labels != null) {
3718 target.labels = new Dictionary<string, object> ();
3720 foreach (var entry in pb.labels) {
3721 var list = entry.Value as List<LabeledStatement>;
3724 var list_clone = new List<LabeledStatement> ();
3725 foreach (var lentry in list) {
3726 list_clone.Add (RemapLabeledStatement (lentry, lentry.Block, clonectx.RemapBlockCopy (lentry.Block)));
3729 target.labels.Add (entry.Key, list_clone);
3731 var labeled = (LabeledStatement) entry.Value;
3732 target.labels.Add (entry.Key, RemapLabeledStatement (labeled, labeled.Block, clonectx.RemapBlockCopy (labeled.Block)));
3739 if (pb.Parent == null)
3742 pb = pb.Parent.ParametersBlock;
3746 public override Expression CreateExpressionTree (ResolveContext ec)
3748 if (statements.Count == 1) {
3749 Expression expr = statements[0].CreateExpressionTree (ec);
3750 if (scope_initializers != null)
3751 expr = new BlockScopeExpression (expr, this);
3756 return base.CreateExpressionTree (ec);
3759 public override void Emit (EmitContext ec)
3761 if (state_machine != null && state_machine.OriginalSourceBlock != this) {
3762 DefineStoreyContainer (ec, state_machine);
3763 state_machine.EmitStoreyInstantiation (ec, this);
3769 public void EmitEmbedded (EmitContext ec)
3771 if (state_machine != null && state_machine.OriginalSourceBlock != this) {
3772 DefineStoreyContainer (ec, state_machine);
3773 state_machine.EmitStoreyInstantiation (ec, this);
3779 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
3781 var res = base.DoFlowAnalysis (fc);
3783 if (HasReachableClosingBrace)
3784 CheckControlExit (fc);
3789 public LabeledStatement GetLabel (string name, Block block)
3792 // Cloned parameters blocks can have their own cloned version of top-level labels
3794 if (labels == null) {
3796 return Parent.ParametersBlock.GetLabel (name, block);
3802 if (!labels.TryGetValue (name, out value)) {
3806 var label = value as LabeledStatement;
3808 if (label != null) {
3809 if (IsLabelVisible (label, b))
3813 List<LabeledStatement> list = (List<LabeledStatement>) value;
3814 for (int i = 0; i < list.Count; ++i) {
3816 if (IsLabelVisible (label, b))
3824 static bool IsLabelVisible (LabeledStatement label, Block b)
3827 if (label.Block == b)
3830 } while (b != null);
3835 public ParameterInfo GetParameterInfo (Parameter p)
3837 for (int i = 0; i < parameters.Count; ++i) {
3838 if (parameters[i] == p)
3839 return parameter_info[i];
3842 throw new ArgumentException ("Invalid parameter");
3845 public ParameterReference GetParameterReference (int index, Location loc)
3847 return new ParameterReference (parameter_info[index], loc);
3850 public Statement PerformClone ()
3852 CloneContext clonectx = new CloneContext ();
3853 return Clone (clonectx);
3856 protected void ProcessParameters ()
3858 if (parameters.Count == 0)
3861 parameter_info = new ParameterInfo[parameters.Count];
3862 for (int i = 0; i < parameter_info.Length; ++i) {
3863 var p = parameters.FixedParameters[i];
3867 // TODO: Should use Parameter only and more block there
3868 parameter_info[i] = new ParameterInfo (this, i);
3870 AddLocalName (p.Name, parameter_info[i]);
3874 static LabeledStatement RemapLabeledStatement (LabeledStatement stmt, Block src, Block dst)
3876 var src_stmts = src.Statements;
3877 for (int i = 0; i < src_stmts.Count; ++i) {
3878 if (src_stmts[i] == stmt)
3879 return (LabeledStatement) dst.Statements[i];
3882 throw new InternalErrorException ("Should never be reached");
3885 public override bool Resolve (BlockContext bc)
3887 // TODO: if ((flags & Flags.Resolved) != 0)
3894 if (bc.HasSet (ResolveContext.Options.ExpressionTreeConversion))
3895 flags |= Flags.IsExpressionTree;
3898 PrepareAssignmentAnalysis (bc);
3900 if (!base.Resolve (bc))
3903 } catch (Exception e) {
3904 if (e is CompletionResult || bc.Report.IsDisabled || e is FatalException || bc.Report.Printer is NullReportPrinter || bc.Module.Compiler.Settings.BreakOnInternalError)
3907 if (bc.CurrentBlock != null) {
3908 bc.Report.Error (584, bc.CurrentBlock.StartLocation, "Internal compiler error: {0}", e.Message);
3910 bc.Report.Error (587, "Internal compiler error: {0}", e.Message);
3915 // If an asynchronous body of F is either an expression classified as nothing, or a
3916 // statement block where no return statements have expressions, the inferred return type is Task
3919 var am = bc.CurrentAnonymousMethod as AnonymousMethodBody;
3920 if (am != null && am.ReturnTypeInference != null && !am.ReturnTypeInference.HasBounds (0)) {
3921 am.ReturnTypeInference = null;
3922 am.ReturnType = bc.Module.PredefinedTypes.Task.TypeSpec;
3930 void PrepareAssignmentAnalysis (BlockContext bc)
3932 for (int i = 0; i < parameters.Count; ++i) {
3933 var par = parameters.FixedParameters[i];
3935 if ((par.ModFlags & Parameter.Modifier.OUT) == 0)
3938 parameter_info [i].VariableInfo = VariableInfo.Create (bc, (Parameter) par);
3942 public ToplevelBlock ConvertToIterator (IMethodData method, TypeDefinition host, TypeSpec iterator_type, bool is_enumerable)
3944 var iterator = new Iterator (this, method, host, iterator_type, is_enumerable);
3945 var stateMachine = new IteratorStorey (iterator);
3947 state_machine = stateMachine;
3948 iterator.SetStateMachine (stateMachine);
3950 var tlb = new ToplevelBlock (host.Compiler, Parameters, Location.Null, Flags.CompilerGenerated);
3951 tlb.Original = this;
3952 tlb.state_machine = stateMachine;
3953 tlb.AddStatement (new Return (iterator, iterator.Location));
3957 public ParametersBlock ConvertToAsyncTask (IMemberContext context, TypeDefinition host, ParametersCompiled parameters, TypeSpec returnType, TypeSpec delegateType, Location loc)
3959 for (int i = 0; i < parameters.Count; i++) {
3960 Parameter p = parameters[i];
3961 Parameter.Modifier mod = p.ModFlags;
3962 if ((mod & Parameter.Modifier.RefOutMask) != 0) {
3963 host.Compiler.Report.Error (1988, p.Location,
3964 "Async methods cannot have ref or out parameters");
3968 if (p is ArglistParameter) {
3969 host.Compiler.Report.Error (4006, p.Location,
3970 "__arglist is not allowed in parameter list of async methods");
3974 if (parameters.Types[i].IsPointer) {
3975 host.Compiler.Report.Error (4005, p.Location,
3976 "Async methods cannot have unsafe parameters");
3982 host.Compiler.Report.Warning (1998, 1, loc,
3983 "Async block lacks `await' operator and will run synchronously");
3986 var block_type = host.Module.Compiler.BuiltinTypes.Void;
3987 var initializer = new AsyncInitializer (this, host, block_type);
3988 initializer.Type = block_type;
3989 initializer.DelegateType = delegateType;
3991 var stateMachine = new AsyncTaskStorey (this, context, initializer, returnType);
3993 state_machine = stateMachine;
3994 initializer.SetStateMachine (stateMachine);
3996 const Flags flags = Flags.CompilerGenerated;
3998 var b = this is ToplevelBlock ?
3999 new ToplevelBlock (host.Compiler, Parameters, Location.Null, flags) :
4000 new ParametersBlock (Parent, parameters, Location.Null, flags | Flags.HasAsyncModifier);
4003 b.state_machine = stateMachine;
4004 b.AddStatement (new AsyncInitializerStatement (initializer));
4012 public class ToplevelBlock : ParametersBlock
4014 LocalVariable this_variable;
4015 CompilerContext compiler;
4016 Dictionary<string, object> names;
4018 List<ExplicitBlock> this_references;
4020 public ToplevelBlock (CompilerContext ctx, Location loc)
4021 : this (ctx, ParametersCompiled.EmptyReadOnlyParameters, loc)
4025 public ToplevelBlock (CompilerContext ctx, ParametersCompiled parameters, Location start, Flags flags = 0)
4026 : base (parameters, start)
4028 this.compiler = ctx;
4032 ProcessParameters ();
4036 // Recreates a top level block from parameters block. Used for
4037 // compiler generated methods where the original block comes from
4038 // explicit child block. This works for already resolved blocks
4039 // only to ensure we resolve them in the correct flow order
4041 public ToplevelBlock (ParametersBlock source, ParametersCompiled parameters)
4042 : base (source, parameters)
4044 this.compiler = source.TopBlock.compiler;
4048 public bool IsIterator {
4050 return (flags & Flags.Iterator) != 0;
4053 flags = value ? flags | Flags.Iterator : flags & ~Flags.Iterator;
4057 public Report Report {
4059 return compiler.Report;
4064 // Used by anonymous blocks to track references of `this' variable
4066 public List<ExplicitBlock> ThisReferencesFromChildrenBlock {
4068 return this_references;
4073 // Returns the "this" instance variable of this block.
4074 // See AddThisVariable() for more information.
4076 public LocalVariable ThisVariable {
4078 return this_variable;
4082 public void AddLocalName (string name, INamedBlockVariable li, bool ignoreChildrenBlocks)
4085 names = new Dictionary<string, object> ();
4088 if (!names.TryGetValue (name, out value)) {
4089 names.Add (name, li);
4093 INamedBlockVariable existing = value as INamedBlockVariable;
4094 List<INamedBlockVariable> existing_list;
4095 if (existing != null) {
4096 existing_list = new List<INamedBlockVariable> ();
4097 existing_list.Add (existing);
4098 names[name] = existing_list;
4100 existing_list = (List<INamedBlockVariable>) value;
4104 // A collision checking between local names
4106 var variable_block = li.Block.Explicit;
4107 for (int i = 0; i < existing_list.Count; ++i) {
4108 existing = existing_list[i];
4109 Block b = existing.Block.Explicit;
4111 // Collision at same level
4112 if (variable_block == b) {
4113 li.Block.Error_AlreadyDeclared (name, li);
4117 // Collision with parent
4118 Block parent = variable_block;
4119 while ((parent = parent.Parent) != null) {
4121 li.Block.Error_AlreadyDeclared (name, li, "parent or current");
4122 i = existing_list.Count;
4127 if (!ignoreChildrenBlocks && variable_block.Parent != b.Parent) {
4128 // Collision with children
4129 while ((b = b.Parent) != null) {
4130 if (variable_block == b) {
4131 li.Block.Error_AlreadyDeclared (name, li, "child");
4132 i = existing_list.Count;
4139 existing_list.Add (li);
4142 public void AddLabel (string name, LabeledStatement label)
4145 labels = new Dictionary<string, object> ();
4148 if (!labels.TryGetValue (name, out value)) {
4149 labels.Add (name, label);
4153 LabeledStatement existing = value as LabeledStatement;
4154 List<LabeledStatement> existing_list;
4155 if (existing != null) {
4156 existing_list = new List<LabeledStatement> ();
4157 existing_list.Add (existing);
4158 labels[name] = existing_list;
4160 existing_list = (List<LabeledStatement>) value;
4164 // A collision checking between labels
4166 for (int i = 0; i < existing_list.Count; ++i) {
4167 existing = existing_list[i];
4168 Block b = existing.Block;
4170 // Collision at same level
4171 if (label.Block == b) {
4172 Report.SymbolRelatedToPreviousError (existing.loc, name);
4173 Report.Error (140, label.loc, "The label `{0}' is a duplicate", name);
4177 // Collision with parent
4179 while ((b = b.Parent) != null) {
4180 if (existing.Block == b) {
4181 Report.Error (158, label.loc,
4182 "The label `{0}' shadows another label by the same name in a contained scope", name);
4183 i = existing_list.Count;
4188 // Collision with with children
4190 while ((b = b.Parent) != null) {
4191 if (label.Block == b) {
4192 Report.Error (158, label.loc,
4193 "The label `{0}' shadows another label by the same name in a contained scope", name);
4194 i = existing_list.Count;
4200 existing_list.Add (label);
4203 public void AddThisReferenceFromChildrenBlock (ExplicitBlock block)
4205 if (this_references == null)
4206 this_references = new List<ExplicitBlock> ();
4208 if (!this_references.Contains (block))
4209 this_references.Add (block);
4212 public void RemoveThisReferenceFromChildrenBlock (ExplicitBlock block)
4214 this_references.Remove (block);
4218 // Creates an arguments set from all parameters, useful for method proxy calls
4220 public Arguments GetAllParametersArguments ()
4222 int count = parameters.Count;
4223 Arguments args = new Arguments (count);
4224 for (int i = 0; i < count; ++i) {
4225 var pi = parameter_info[i];
4226 var arg_expr = GetParameterReference (i, pi.Location);
4228 Argument.AType atype_modifier;
4229 switch (pi.Parameter.ParameterModifier & Parameter.Modifier.RefOutMask) {
4230 case Parameter.Modifier.REF:
4231 atype_modifier = Argument.AType.Ref;
4233 case Parameter.Modifier.OUT:
4234 atype_modifier = Argument.AType.Out;
4241 args.Add (new Argument (arg_expr, atype_modifier));
4248 // Lookup inside a block, the returned value can represent 3 states
4250 // true+variable: A local name was found and it's valid
4251 // false+variable: A local name was found in a child block only
4252 // false+null: No local name was found
4254 public bool GetLocalName (string name, Block block, ref INamedBlockVariable variable)
4260 if (!names.TryGetValue (name, out value))
4263 variable = value as INamedBlockVariable;
4265 if (variable != null) {
4267 if (variable.Block == b.Original)
4271 } while (b != null);
4279 } while (b != null);
4281 List<INamedBlockVariable> list = (List<INamedBlockVariable>) value;
4282 for (int i = 0; i < list.Count; ++i) {
4285 if (variable.Block == b.Original)
4289 } while (b != null);
4297 } while (b != null);
4307 public void IncludeBlock (ParametersBlock pb, ToplevelBlock block)
4309 if (block.names != null) {
4310 foreach (var n in block.names) {
4311 var variable = n.Value as INamedBlockVariable;
4312 if (variable != null) {
4313 if (variable.Block.ParametersBlock == pb)
4314 AddLocalName (n.Key, variable, false);
4318 foreach (var v in (List<INamedBlockVariable>) n.Value)
4319 if (v.Block.ParametersBlock == pb)
4320 AddLocalName (n.Key, v, false);
4326 // This is used by non-static `struct' constructors which do not have an
4327 // initializer - in this case, the constructor must initialize all of the
4328 // struct's fields. To do this, we add a "this" variable and use the flow
4329 // analysis code to ensure that it's been fully initialized before control
4330 // leaves the constructor.
4332 public void AddThisVariable (BlockContext bc)
4334 if (this_variable != null)
4335 throw new InternalErrorException (StartLocation.ToString ());
4337 this_variable = new LocalVariable (this, "this", LocalVariable.Flags.IsThis | LocalVariable.Flags.Used, StartLocation);
4338 this_variable.Type = bc.CurrentType;
4339 this_variable.PrepareAssignmentAnalysis (bc);
4342 public override void CheckControlExit (FlowAnalysisContext fc, DefiniteAssignmentBitSet dat)
4345 // If we're a non-static struct constructor which doesn't have an
4346 // initializer, then we must initialize all of the struct's fields.
4348 if (this_variable != null)
4349 this_variable.IsThisAssigned (fc, this);
4351 base.CheckControlExit (fc, dat);
4354 public override void Emit (EmitContext ec)
4356 if (Report.Errors > 0)
4360 if (IsCompilerGenerated) {
4361 using (ec.With (BuilderContext.Options.OmitDebugInfo, true)) {
4369 // If `HasReturnLabel' is set, then we already emitted a
4370 // jump to the end of the method, so we must emit a `ret'
4373 // Unfortunately, System.Reflection.Emit automatically emits
4374 // a leave to the end of a finally block. This is a problem
4375 // if no code is following the try/finally block since we may
4376 // jump to a point after the end of the method.
4377 // As a workaround, we're always creating a return label in
4380 if (ec.HasReturnLabel || HasReachableClosingBrace) {
4381 if (ec.HasReturnLabel)
4382 ec.MarkLabel (ec.ReturnLabel);
4384 if (ec.EmitAccurateDebugInfo && !IsCompilerGenerated)
4385 ec.Mark (EndLocation);
4387 if (ec.ReturnType.Kind != MemberKind.Void)
4388 ec.Emit (OpCodes.Ldloc, ec.TemporaryReturn ());
4390 ec.Emit (OpCodes.Ret);
4393 } catch (Exception e) {
4394 throw new InternalErrorException (e, StartLocation);
4398 public bool Resolve (BlockContext bc, IMethodData md)
4403 var errors = bc.Report.Errors;
4407 if (bc.Report.Errors > errors)
4410 MarkReachable (new Reachability ());
4412 if (HasReachableClosingBrace && bc.ReturnType.Kind != MemberKind.Void) {
4413 // TODO: var md = bc.CurrentMemberDefinition;
4414 bc.Report.Error (161, md.Location, "`{0}': not all code paths return a value", md.GetSignatureForError ());
4417 if ((flags & Flags.NoFlowAnalysis) != 0)
4420 var fc = new FlowAnalysisContext (bc.Module.Compiler, this, bc.AssignmentInfoOffset);
4423 } catch (Exception e) {
4424 throw new InternalErrorException (e, StartLocation);
4431 public class SwitchLabel : Statement
4439 // if expr == null, then it is the default case.
4441 public SwitchLabel (Expression expr, Location l)
4447 public bool IsDefault {
4449 return label == null;
4453 public Expression Label {
4459 public Location Location {
4465 public Constant Converted {
4474 public bool PatternMatching { get; set; }
4476 public bool SectionStart { get; set; }
4478 public Label GetILLabel (EmitContext ec)
4480 if (il_label == null){
4481 il_label = ec.DefineLabel ();
4484 return il_label.Value;
4487 protected override void DoEmit (EmitContext ec)
4489 ec.MarkLabel (GetILLabel (ec));
4492 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
4497 fc.DefiniteAssignment = new DefiniteAssignmentBitSet (fc.SwitchInitialDefinitiveAssignment);
4501 public override bool Resolve (BlockContext bc)
4503 if (ResolveAndReduce (bc))
4504 bc.Switch.RegisterLabel (bc, this);
4510 // Resolves the expression, reduces it to a literal if possible
4511 // and then converts it to the requested type.
4513 bool ResolveAndReduce (BlockContext bc)
4518 var switch_statement = bc.Switch;
4520 if (PatternMatching) {
4521 label = new Is (switch_statement.ExpressionValue, label, loc).Resolve (bc);
4522 return label != null;
4525 var c = label.ResolveLabelConstant (bc);
4529 if (switch_statement.IsNullable && c is NullLiteral) {
4534 if (switch_statement.IsPatternMatching) {
4535 label = new Is (switch_statement.ExpressionValue, label, loc).Resolve (bc);
4539 converted = c.ImplicitConversionRequired (bc, switch_statement.SwitchType);
4540 return converted != null;
4543 public void Error_AlreadyOccurs (ResolveContext ec, SwitchLabel collision_with)
4545 ec.Report.SymbolRelatedToPreviousError (collision_with.loc, null);
4546 ec.Report.Error (152, loc, "The label `{0}' already occurs in this switch statement", GetSignatureForError ());
4549 protected override void CloneTo (CloneContext clonectx, Statement target)
4551 var t = (SwitchLabel) target;
4553 t.label = label.Clone (clonectx);
4556 public override object Accept (StructuralVisitor visitor)
4558 return visitor.Visit (this);
4561 public string GetSignatureForError ()
4564 if (converted == null)
4567 label = converted.GetValueAsLiteral ();
4569 return string.Format ("case {0}:", label);
4573 public class Switch : LoopStatement
4575 // structure used to hold blocks of keys while calculating table switch
4576 sealed class LabelsRange : IComparable<LabelsRange>
4578 public readonly long min;
4580 public readonly List<long> label_values;
4582 public LabelsRange (long value)
4585 label_values = new List<long> ();
4586 label_values.Add (value);
4589 public LabelsRange (long min, long max, ICollection<long> values)
4593 this.label_values = new List<long> (values);
4598 return max - min + 1;
4602 public bool AddValue (long value)
4604 var gap = value - min + 1;
4605 // Ensure the range has > 50% occupancy
4606 if (gap > 2 * (label_values.Count + 1) || gap <= 0)
4610 label_values.Add (value);
4614 public int CompareTo (LabelsRange other)
4616 int nLength = label_values.Count;
4617 int nLengthOther = other.label_values.Count;
4618 if (nLengthOther == nLength)
4619 return (int) (other.min - min);
4621 return nLength - nLengthOther;
4625 sealed class DispatchStatement : Statement
4627 readonly Switch body;
4629 public DispatchStatement (Switch body)
4634 protected override void CloneTo (CloneContext clonectx, Statement target)
4636 throw new NotImplementedException ();
4639 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
4644 protected override void DoEmit (EmitContext ec)
4646 body.EmitDispatch (ec);
4650 class MissingBreak : Statement
4652 readonly SwitchLabel label;
4654 public MissingBreak (SwitchLabel sl)
4660 public bool FallOut { get; set; }
4662 protected override void DoEmit (EmitContext ec)
4666 protected override void CloneTo (CloneContext clonectx, Statement target)
4670 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
4673 fc.Report.Error (8070, loc, "Control cannot fall out of switch statement through final case label `{0}'",
4674 label.GetSignatureForError ());
4676 fc.Report.Error (163, loc, "Control cannot fall through from one case label `{0}' to another",
4677 label.GetSignatureForError ());
4683 public Expression Expr;
4686 // Mapping of all labels to their SwitchLabels
4688 Dictionary<long, SwitchLabel> labels;
4689 Dictionary<string, SwitchLabel> string_labels;
4690 List<SwitchLabel> case_labels;
4692 List<Tuple<GotoCase, Constant>> goto_cases;
4693 List<DefiniteAssignmentBitSet> end_reachable_das;
4696 /// The governing switch type
4698 public TypeSpec SwitchType;
4700 Expression new_expr;
4702 SwitchLabel case_null;
4703 SwitchLabel case_default;
4705 Label defaultLabel, nullLabel;
4706 VariableReference value;
4707 ExpressionStatement string_dictionary;
4708 FieldExpr switch_cache_field;
4709 ExplicitBlock block;
4713 // Nullable Types support
4715 Nullable.Unwrap unwrap;
4717 public Switch (Expression e, ExplicitBlock block, Location l)
4725 public SwitchLabel ActiveLabel { get; set; }
4727 public ExplicitBlock Block {
4733 public SwitchLabel DefaultLabel {
4735 return case_default;
4739 public bool IsNullable {
4741 return unwrap != null;
4745 public bool IsPatternMatching {
4747 return new_expr == null && SwitchType != null;
4751 public List<SwitchLabel> RegisteredLabels {
4757 public VariableReference ExpressionValue {
4764 // Determines the governing type for a switch. The returned
4765 // expression might be the expression from the switch, or an
4766 // expression that includes any potential conversions to
4768 static Expression SwitchGoverningType (ResolveContext rc, Expression expr, bool unwrapExpr)
4770 switch (expr.Type.BuiltinType) {
4771 case BuiltinTypeSpec.Type.Byte:
4772 case BuiltinTypeSpec.Type.SByte:
4773 case BuiltinTypeSpec.Type.UShort:
4774 case BuiltinTypeSpec.Type.Short:
4775 case BuiltinTypeSpec.Type.UInt:
4776 case BuiltinTypeSpec.Type.Int:
4777 case BuiltinTypeSpec.Type.ULong:
4778 case BuiltinTypeSpec.Type.Long:
4779 case BuiltinTypeSpec.Type.Char:
4780 case BuiltinTypeSpec.Type.String:
4781 case BuiltinTypeSpec.Type.Bool:
4785 if (expr.Type.IsEnum)
4789 // Try to find a *user* defined implicit conversion.
4791 // If there is no implicit conversion, or if there are multiple
4792 // conversions, we have to report an error
4794 Expression converted = null;
4795 foreach (TypeSpec tt in rc.Module.PredefinedTypes.SwitchUserTypes) {
4797 if (!unwrapExpr && tt.IsNullableType && expr.Type.IsNullableType)
4800 var restr = Convert.UserConversionRestriction.ImplicitOnly |
4801 Convert.UserConversionRestriction.ProbingOnly;
4804 restr |= Convert.UserConversionRestriction.NullableSourceOnly;
4806 var e = Convert.UserDefinedConversion (rc, expr, tt, restr, Location.Null);
4811 // Ignore over-worked ImplicitUserConversions that do
4812 // an implicit conversion in addition to the user conversion.
4814 var uc = e as UserCast;
4818 if (converted != null){
4819 // rc.Report.ExtraInformation (loc, "(Ambiguous implicit user defined conversion in previous ");
4828 public static TypeSpec[] CreateSwitchUserTypes (ModuleContainer module, TypeSpec nullable)
4830 var types = module.Compiler.BuiltinTypes;
4832 // LAMESPEC: For some reason it does not contain bool which looks like csc bug
4833 TypeSpec[] stypes = new[] {
4846 if (nullable != null) {
4848 Array.Resize (ref stypes, stypes.Length + 9);
4850 for (int i = 0; i < 9; ++i) {
4851 stypes [10 + i] = nullable.MakeGenericType (module, new [] { stypes [i] });
4858 public void RegisterLabel (BlockContext rc, SwitchLabel sl)
4860 case_labels.Add (sl);
4863 if (case_default != null) {
4864 sl.Error_AlreadyOccurs (rc, case_default);
4872 if (sl.Converted == null)
4876 if (string_labels != null) {
4877 string string_value = sl.Converted.GetValue () as string;
4878 if (string_value == null)
4881 string_labels.Add (string_value, sl);
4883 if (sl.Converted.IsNull) {
4886 labels.Add (sl.Converted.GetValueAsLong (), sl);
4889 } catch (ArgumentException) {
4890 if (string_labels != null)
4891 sl.Error_AlreadyOccurs (rc, string_labels[(string) sl.Converted.GetValue ()]);
4893 sl.Error_AlreadyOccurs (rc, labels[sl.Converted.GetValueAsLong ()]);
4898 // This method emits code for a lookup-based switch statement (non-string)
4899 // Basically it groups the cases into blocks that are at least half full,
4900 // and then spits out individual lookup opcodes for each block.
4901 // It emits the longest blocks first, and short blocks are just
4902 // handled with direct compares.
4904 void EmitTableSwitch (EmitContext ec, Expression val)
4906 if (labels != null && labels.Count > 0) {
4907 List<LabelsRange> ranges;
4908 if (string_labels != null) {
4909 // We have done all hard work for string already
4910 // setup single range only
4911 ranges = new List<LabelsRange> (1);
4912 ranges.Add (new LabelsRange (0, labels.Count - 1, labels.Keys));
4914 var element_keys = new long[labels.Count];
4915 labels.Keys.CopyTo (element_keys, 0);
4916 Array.Sort (element_keys);
4919 // Build possible ranges of switch labes to reduce number
4922 ranges = new List<LabelsRange> (element_keys.Length);
4923 var range = new LabelsRange (element_keys[0]);
4925 for (int i = 1; i < element_keys.Length; ++i) {
4926 var l = element_keys[i];
4927 if (range.AddValue (l))
4930 range = new LabelsRange (l);
4934 // sort the blocks so we can tackle the largest ones first
4938 Label lbl_default = defaultLabel;
4939 TypeSpec compare_type = SwitchType.IsEnum ? EnumSpec.GetUnderlyingType (SwitchType) : SwitchType;
4941 for (int range_index = ranges.Count - 1; range_index >= 0; --range_index) {
4942 LabelsRange kb = ranges[range_index];
4943 lbl_default = (range_index == 0) ? defaultLabel : ec.DefineLabel ();
4945 // Optimize small ranges using simple equality check
4946 if (kb.Range <= 2) {
4947 foreach (var key in kb.label_values) {
4948 SwitchLabel sl = labels[key];
4949 if (sl == case_default || sl == case_null)
4952 if (sl.Converted.IsZeroInteger) {
4953 val.EmitBranchable (ec, sl.GetILLabel (ec), false);
4956 sl.Converted.Emit (ec);
4957 ec.Emit (OpCodes.Beq, sl.GetILLabel (ec));
4961 // TODO: if all the keys in the block are the same and there are
4962 // no gaps/defaults then just use a range-check.
4963 if (compare_type.BuiltinType == BuiltinTypeSpec.Type.Long || compare_type.BuiltinType == BuiltinTypeSpec.Type.ULong) {
4964 // TODO: optimize constant/I4 cases
4966 // check block range (could be > 2^31)
4968 ec.EmitLong (kb.min);
4969 ec.Emit (OpCodes.Blt, lbl_default);
4972 ec.EmitLong (kb.max);
4973 ec.Emit (OpCodes.Bgt, lbl_default);
4978 ec.EmitLong (kb.min);
4979 ec.Emit (OpCodes.Sub);
4982 ec.Emit (OpCodes.Conv_I4); // assumes < 2^31 labels!
4986 int first = (int) kb.min;
4989 ec.Emit (OpCodes.Sub);
4990 } else if (first < 0) {
4991 ec.EmitInt (-first);
4992 ec.Emit (OpCodes.Add);
4996 // first, build the list of labels for the switch
4998 long cJumps = kb.Range;
4999 Label[] switch_labels = new Label[cJumps];
5000 for (int iJump = 0; iJump < cJumps; iJump++) {
5001 var key = kb.label_values[iKey];
5002 if (key == kb.min + iJump) {
5003 switch_labels[iJump] = labels[key].GetILLabel (ec);
5006 switch_labels[iJump] = lbl_default;
5010 // emit the switch opcode
5011 ec.Emit (OpCodes.Switch, switch_labels);
5014 // mark the default for this block
5015 if (range_index != 0)
5016 ec.MarkLabel (lbl_default);
5019 // the last default just goes to the end
5020 if (ranges.Count > 0)
5021 ec.Emit (OpCodes.Br, lbl_default);
5025 public SwitchLabel FindLabel (Constant value)
5027 SwitchLabel sl = null;
5029 if (string_labels != null) {
5030 string s = value.GetValue () as string;
5032 if (case_null != null)
5034 else if (case_default != null)
5037 string_labels.TryGetValue (s, out sl);
5040 if (value is NullLiteral) {
5043 labels.TryGetValue (value.GetValueAsLong (), out sl);
5050 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
5052 Expr.FlowAnalysis (fc);
5054 var prev_switch = fc.SwitchInitialDefinitiveAssignment;
5055 var InitialDefinitiveAssignment = fc.DefiniteAssignment;
5056 fc.SwitchInitialDefinitiveAssignment = InitialDefinitiveAssignment;
5058 block.FlowAnalysis (fc);
5060 fc.SwitchInitialDefinitiveAssignment = prev_switch;
5062 if (end_reachable_das != null) {
5063 var sections_das = DefiniteAssignmentBitSet.And (end_reachable_das);
5064 InitialDefinitiveAssignment |= sections_das;
5065 end_reachable_das = null;
5068 fc.DefiniteAssignment = InitialDefinitiveAssignment;
5070 return case_default != null && !end_reachable;
5073 public override bool Resolve (BlockContext ec)
5075 Expr = Expr.Resolve (ec);
5080 // LAMESPEC: User conversion from non-nullable governing type has a priority
5082 new_expr = SwitchGoverningType (ec, Expr, false);
5084 if (new_expr == null) {
5085 if (Expr.Type.IsNullableType) {
5086 unwrap = Nullable.Unwrap.Create (Expr, false);
5091 // Unwrap + user conversion using non-nullable type is not allowed but user operator
5092 // involving nullable Expr and nullable governing type is
5094 new_expr = SwitchGoverningType (ec, unwrap, true);
5098 Expression switch_expr;
5099 if (new_expr == null) {
5100 if (ec.Module.Compiler.Settings.Version != LanguageVersion.Experimental) {
5101 if (Expr.Type != InternalType.ErrorType) {
5102 ec.Report.Error (151, loc,
5103 "A switch expression of type `{0}' cannot be converted to an integral type, bool, char, string, enum or nullable type",
5104 Expr.Type.GetSignatureForError ());
5111 SwitchType = Expr.Type;
5113 switch_expr = new_expr;
5114 SwitchType = new_expr.Type;
5115 if (SwitchType.IsNullableType) {
5116 new_expr = unwrap = Nullable.Unwrap.Create (new_expr, true);
5117 SwitchType = Nullable.NullableInfo.GetUnderlyingType (SwitchType);
5120 if (SwitchType.BuiltinType == BuiltinTypeSpec.Type.Bool && ec.Module.Compiler.Settings.Version == LanguageVersion.ISO_1) {
5121 ec.Report.FeatureIsNotAvailable (ec.Module.Compiler, loc, "switch expression of boolean type");
5125 if (block.Statements.Count == 0)
5128 if (SwitchType.BuiltinType == BuiltinTypeSpec.Type.String) {
5129 string_labels = new Dictionary<string, SwitchLabel> ();
5131 labels = new Dictionary<long, SwitchLabel> ();
5135 var constant = switch_expr as Constant;
5138 // Don't need extra variable for constant switch or switch with
5139 // only default case
5141 if (constant == null) {
5143 // Store switch expression for comparison purposes
5145 value = switch_expr as VariableReference;
5146 if (value == null && !HasOnlyDefaultSection ()) {
5147 var current_block = ec.CurrentBlock;
5148 ec.CurrentBlock = Block;
5149 // Create temporary variable inside switch scope
5150 value = TemporaryVariableReference.Create (SwitchType, ec.CurrentBlock, loc);
5152 ec.CurrentBlock = current_block;
5156 case_labels = new List<SwitchLabel> ();
5158 Switch old_switch = ec.Switch;
5160 var parent_los = ec.EnclosingLoopOrSwitch;
5161 ec.EnclosingLoopOrSwitch = this;
5163 var ok = Statement.Resolve (ec);
5165 ec.EnclosingLoopOrSwitch = parent_los;
5166 ec.Switch = old_switch;
5169 // Check if all goto cases are valid. Needs to be done after switch
5170 // is resolved because goto can jump forward in the scope.
5172 if (goto_cases != null) {
5173 foreach (var gc in goto_cases) {
5174 if (gc.Item1 == null) {
5175 if (DefaultLabel == null) {
5176 Goto.Error_UnknownLabel (ec, "default", loc);
5182 var sl = FindLabel (gc.Item2);
5184 Goto.Error_UnknownLabel (ec, "case " + gc.Item2.GetValueAsLiteral (), loc);
5186 gc.Item1.Label = sl;
5194 if (constant == null && SwitchType.BuiltinType == BuiltinTypeSpec.Type.String && string_labels.Count > 6) {
5195 ResolveStringSwitchMap (ec);
5199 // Anonymous storey initialization has to happen before
5200 // any generated switch dispatch
5202 block.InsertStatement (0, new DispatchStatement (this));
5207 bool HasOnlyDefaultSection ()
5209 for (int i = 0; i < block.Statements.Count; ++i) {
5210 var s = block.Statements[i] as SwitchLabel;
5212 if (s == null || s.IsDefault)
5221 public override Reachability MarkReachable (Reachability rc)
5223 if (rc.IsUnreachable)
5226 base.MarkReachable (rc);
5228 block.MarkReachableScope (rc);
5230 if (block.Statements.Count == 0)
5233 SwitchLabel constant_label = null;
5234 var constant = new_expr as Constant;
5236 if (constant != null) {
5237 constant_label = FindLabel (constant) ?? case_default;
5238 if (constant_label == null) {
5239 block.Statements.RemoveAt (0);
5244 var section_rc = new Reachability ();
5245 SwitchLabel prev_label = null;
5247 for (int i = 0; i < block.Statements.Count; ++i) {
5248 var s = block.Statements[i];
5249 var sl = s as SwitchLabel;
5251 if (sl != null && sl.SectionStart) {
5253 // Section is marked already via goto case
5255 if (!sl.IsUnreachable) {
5256 section_rc = new Reachability ();
5260 if (constant_label != null && constant_label != sl)
5261 section_rc = Reachability.CreateUnreachable ();
5262 else if (section_rc.IsUnreachable) {
5263 section_rc = new Reachability ();
5265 if (prev_label != null) {
5266 sl.SectionStart = false;
5267 s = new MissingBreak (prev_label);
5268 s.MarkReachable (rc);
5269 block.Statements.Insert (i - 1, s);
5277 section_rc = s.MarkReachable (section_rc);
5280 if (!section_rc.IsUnreachable && prev_label != null) {
5281 prev_label.SectionStart = false;
5282 var s = new MissingBreak (prev_label) {
5286 s.MarkReachable (rc);
5287 block.Statements.Add (s);
5291 // Reachability can affect parent only when all possible paths are handled but
5292 // we still need to run reachability check on switch body to check for fall-through
5294 if (case_default == null && constant_label == null)
5298 // We have at least one local exit from the switch
5303 return Reachability.CreateUnreachable ();
5306 public void RegisterGotoCase (GotoCase gotoCase, Constant value)
5308 if (goto_cases == null)
5309 goto_cases = new List<Tuple<GotoCase, Constant>> ();
5311 goto_cases.Add (Tuple.Create (gotoCase, value));
5315 // Converts string switch into string hashtable
5317 void ResolveStringSwitchMap (ResolveContext ec)
5319 FullNamedExpression string_dictionary_type;
5320 if (ec.Module.PredefinedTypes.Dictionary.Define ()) {
5321 string_dictionary_type = new TypeExpression (
5322 ec.Module.PredefinedTypes.Dictionary.TypeSpec.MakeGenericType (ec,
5323 new [] { ec.BuiltinTypes.String, ec.BuiltinTypes.Int }),
5325 } else if (ec.Module.PredefinedTypes.Hashtable.Define ()) {
5326 string_dictionary_type = new TypeExpression (ec.Module.PredefinedTypes.Hashtable.TypeSpec, loc);
5328 ec.Module.PredefinedTypes.Dictionary.Resolve ();
5332 var ctype = ec.CurrentMemberDefinition.Parent.PartialContainer;
5333 Field field = new Field (ctype, string_dictionary_type,
5334 Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED,
5335 new MemberName (CompilerGeneratedContainer.MakeName (null, "f", "switch$map", ec.Module.CounterSwitchTypes++), loc), null);
5336 if (!field.Define ())
5338 ctype.AddField (field);
5340 var init = new List<Expression> ();
5342 labels = new Dictionary<long, SwitchLabel> (string_labels.Count);
5343 string value = null;
5345 foreach (SwitchLabel sl in case_labels) {
5347 if (sl.SectionStart)
5348 labels.Add (++counter, sl);
5350 if (sl == case_default || sl == case_null)
5353 value = (string) sl.Converted.GetValue ();
5354 var init_args = new List<Expression> (2);
5355 init_args.Add (new StringLiteral (ec.BuiltinTypes, value, sl.Location));
5357 sl.Converted = new IntConstant (ec.BuiltinTypes, counter, loc);
5358 init_args.Add (sl.Converted);
5360 init.Add (new CollectionElementInitializer (init_args, loc));
5363 Arguments args = new Arguments (1);
5364 args.Add (new Argument (new IntConstant (ec.BuiltinTypes, init.Count, loc)));
5365 Expression initializer = new NewInitialize (string_dictionary_type, args,
5366 new CollectionOrObjectInitializers (init, loc), loc);
5368 switch_cache_field = new FieldExpr (field, loc);
5369 string_dictionary = new SimpleAssign (switch_cache_field, initializer.Resolve (ec));
5372 void DoEmitStringSwitch (EmitContext ec)
5374 Label l_initialized = ec.DefineLabel ();
5377 // Skip initialization when value is null
5379 value.EmitBranchable (ec, nullLabel, false);
5382 // Check if string dictionary is initialized and initialize
5384 switch_cache_field.EmitBranchable (ec, l_initialized, true);
5385 using (ec.With (BuilderContext.Options.OmitDebugInfo, true)) {
5386 string_dictionary.EmitStatement (ec);
5388 ec.MarkLabel (l_initialized);
5390 LocalTemporary string_switch_variable = new LocalTemporary (ec.BuiltinTypes.Int);
5392 ResolveContext rc = new ResolveContext (ec.MemberContext);
5394 if (switch_cache_field.Type.IsGeneric) {
5395 Arguments get_value_args = new Arguments (2);
5396 get_value_args.Add (new Argument (value));
5397 get_value_args.Add (new Argument (string_switch_variable, Argument.AType.Out));
5398 Expression get_item = new Invocation (new MemberAccess (switch_cache_field, "TryGetValue", loc), get_value_args).Resolve (rc);
5399 if (get_item == null)
5403 // A value was not found, go to default case
5405 get_item.EmitBranchable (ec, defaultLabel, false);
5407 Arguments get_value_args = new Arguments (1);
5408 get_value_args.Add (new Argument (value));
5410 Expression get_item = new ElementAccess (switch_cache_field, get_value_args, loc).Resolve (rc);
5411 if (get_item == null)
5414 LocalTemporary get_item_object = new LocalTemporary (ec.BuiltinTypes.Object);
5415 get_item_object.EmitAssign (ec, get_item, true, false);
5416 ec.Emit (OpCodes.Brfalse, defaultLabel);
5418 ExpressionStatement get_item_int = (ExpressionStatement) new SimpleAssign (string_switch_variable,
5419 new Cast (new TypeExpression (ec.BuiltinTypes.Int, loc), get_item_object, loc)).Resolve (rc);
5421 get_item_int.EmitStatement (ec);
5422 get_item_object.Release (ec);
5425 EmitTableSwitch (ec, string_switch_variable);
5426 string_switch_variable.Release (ec);
5430 // Emits switch using simple if/else comparison for small label count (4 + optional default)
5432 void EmitShortSwitch (EmitContext ec)
5434 MethodSpec equal_method = null;
5435 if (SwitchType.BuiltinType == BuiltinTypeSpec.Type.String) {
5436 equal_method = ec.Module.PredefinedMembers.StringEqual.Resolve (loc);
5439 if (equal_method != null) {
5440 value.EmitBranchable (ec, nullLabel, false);
5443 for (int i = 0; i < case_labels.Count; ++i) {
5444 var label = case_labels [i];
5445 if (label == case_default || label == case_null)
5448 var constant = label.Converted;
5450 if (constant == null) {
5451 label.Label.EmitBranchable (ec, label.GetILLabel (ec), true);
5455 if (equal_method != null) {
5459 var call = new CallEmitter ();
5460 call.EmitPredefined (ec, equal_method, new Arguments (0));
5461 ec.Emit (OpCodes.Brtrue, label.GetILLabel (ec));
5465 if (constant.IsZeroInteger && constant.Type.BuiltinType != BuiltinTypeSpec.Type.Long && constant.Type.BuiltinType != BuiltinTypeSpec.Type.ULong) {
5466 value.EmitBranchable (ec, label.GetILLabel (ec), false);
5472 ec.Emit (OpCodes.Beq, label.GetILLabel (ec));
5475 ec.Emit (OpCodes.Br, defaultLabel);
5478 void EmitDispatch (EmitContext ec)
5480 if (IsPatternMatching) {
5481 EmitShortSwitch (ec);
5485 if (value == null) {
5487 // Constant switch, we've already done the work if there is only 1 label
5491 foreach (var sl in case_labels) {
5492 if (sl.IsUnreachable)
5495 if (reachable++ > 0) {
5496 var constant = (Constant) new_expr;
5497 var constant_label = FindLabel (constant) ?? case_default;
5499 ec.Emit (OpCodes.Br, constant_label.GetILLabel (ec));
5507 if (string_dictionary != null) {
5508 DoEmitStringSwitch (ec);
5509 } else if (case_labels.Count < 4 || string_labels != null) {
5510 EmitShortSwitch (ec);
5512 EmitTableSwitch (ec, value);
5516 protected override void DoEmit (EmitContext ec)
5519 // Setup the codegen context
5521 Label old_end = ec.LoopEnd;
5522 Switch old_switch = ec.Switch;
5524 ec.LoopEnd = ec.DefineLabel ();
5527 defaultLabel = case_default == null ? ec.LoopEnd : case_default.GetILLabel (ec);
5528 nullLabel = case_null == null ? defaultLabel : case_null.GetILLabel (ec);
5530 if (value != null) {
5533 var switch_expr = new_expr ?? Expr;
5535 unwrap.EmitCheck (ec);
5536 ec.Emit (OpCodes.Brfalse, nullLabel);
5537 value.EmitAssign (ec, switch_expr, false, false);
5538 } else if (switch_expr != value) {
5539 value.EmitAssign (ec, switch_expr, false, false);
5544 // Next statement is compiler generated we don't need extra
5545 // nop when we can use the statement for sequence point
5547 ec.Mark (block.StartLocation);
5548 block.IsCompilerGenerated = true;
5550 new_expr.EmitSideEffect (ec);
5555 // Restore context state.
5556 ec.MarkLabel (ec.LoopEnd);
5559 // Restore the previous context
5561 ec.LoopEnd = old_end;
5562 ec.Switch = old_switch;
5565 protected override void CloneTo (CloneContext clonectx, Statement t)
5567 Switch target = (Switch) t;
5569 target.Expr = Expr.Clone (clonectx);
5570 target.Statement = target.block = (ExplicitBlock) block.Clone (clonectx);
5573 public override object Accept (StructuralVisitor visitor)
5575 return visitor.Visit (this);
5578 public override void AddEndDefiniteAssignment (FlowAnalysisContext fc)
5580 if (case_default == null && !(new_expr is Constant))
5583 if (end_reachable_das == null)
5584 end_reachable_das = new List<DefiniteAssignmentBitSet> ();
5586 end_reachable_das.Add (fc.DefiniteAssignment);
5589 public override void SetEndReachable ()
5591 end_reachable = true;
5595 // A place where execution can restart in a state machine
5596 public abstract class ResumableStatement : Statement
5599 protected Label resume_point;
5601 public Label PrepareForEmit (EmitContext ec)
5605 resume_point = ec.DefineLabel ();
5607 return resume_point;
5610 public virtual Label PrepareForDispose (EmitContext ec, Label end)
5615 public virtual void EmitForDispose (EmitContext ec, LocalBuilder pc, Label end, bool have_dispatcher)
5620 public abstract class TryFinallyBlock : ExceptionStatement
5622 protected Statement stmt;
5623 Label dispose_try_block;
5624 bool prepared_for_dispose, emitted_dispose;
5625 Method finally_host;
5627 protected TryFinallyBlock (Statement stmt, Location loc)
5635 public Statement Statement {
5643 protected abstract void EmitTryBody (EmitContext ec);
5644 public abstract void EmitFinallyBody (EmitContext ec);
5646 public override Label PrepareForDispose (EmitContext ec, Label end)
5648 if (!prepared_for_dispose) {
5649 prepared_for_dispose = true;
5650 dispose_try_block = ec.DefineLabel ();
5652 return dispose_try_block;
5655 protected sealed override void DoEmit (EmitContext ec)
5657 EmitTryBodyPrepare (ec);
5660 bool beginFinally = EmitBeginFinallyBlock (ec);
5662 Label start_finally = ec.DefineLabel ();
5663 if (resume_points != null && beginFinally) {
5664 var state_machine = (StateMachineInitializer) ec.CurrentAnonymousMethod;
5666 ec.Emit (OpCodes.Ldloc, state_machine.SkipFinally);
5667 ec.Emit (OpCodes.Brfalse_S, start_finally);
5668 ec.Emit (OpCodes.Endfinally);
5671 ec.MarkLabel (start_finally);
5673 if (finally_host != null) {
5674 finally_host.Define ();
5675 finally_host.PrepareEmit ();
5676 finally_host.Emit ();
5678 // Now it's safe to add, to close it properly and emit sequence points
5679 finally_host.Parent.AddMember (finally_host);
5681 var ce = new CallEmitter ();
5682 ce.InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, loc);
5683 ce.EmitPredefined (ec, finally_host.Spec, new Arguments (0), true);
5685 EmitFinallyBody (ec);
5689 ec.EndExceptionBlock ();
5692 public override void EmitForDispose (EmitContext ec, LocalBuilder pc, Label end, bool have_dispatcher)
5694 if (emitted_dispose)
5697 emitted_dispose = true;
5699 Label end_of_try = ec.DefineLabel ();
5701 // Ensure that the only way we can get into this code is through a dispatcher
5702 if (have_dispatcher)
5703 ec.Emit (OpCodes.Br, end);
5705 ec.BeginExceptionBlock ();
5707 ec.MarkLabel (dispose_try_block);
5709 Label[] labels = null;
5710 for (int i = 0; i < resume_points.Count; ++i) {
5711 ResumableStatement s = resume_points[i];
5712 Label ret = s.PrepareForDispose (ec, end_of_try);
5713 if (ret.Equals (end_of_try) && labels == null)
5715 if (labels == null) {
5716 labels = new Label[resume_points.Count];
5717 for (int j = 0; j < i; ++j)
5718 labels[j] = end_of_try;
5723 if (labels != null) {
5725 for (j = 1; j < labels.Length; ++j)
5726 if (!labels[0].Equals (labels[j]))
5728 bool emit_dispatcher = j < labels.Length;
5730 if (emit_dispatcher) {
5731 ec.Emit (OpCodes.Ldloc, pc);
5732 ec.EmitInt (first_resume_pc);
5733 ec.Emit (OpCodes.Sub);
5734 ec.Emit (OpCodes.Switch, labels);
5737 foreach (ResumableStatement s in resume_points)
5738 s.EmitForDispose (ec, pc, end_of_try, emit_dispatcher);
5741 ec.MarkLabel (end_of_try);
5743 ec.BeginFinallyBlock ();
5745 if (finally_host != null) {
5746 var ce = new CallEmitter ();
5747 ce.InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, loc);
5748 ce.EmitPredefined (ec, finally_host.Spec, new Arguments (0), true);
5750 EmitFinallyBody (ec);
5753 ec.EndExceptionBlock ();
5756 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
5758 var res = stmt.FlowAnalysis (fc);
5763 protected virtual bool EmitBeginFinallyBlock (EmitContext ec)
5765 ec.BeginFinallyBlock ();
5769 public override Reachability MarkReachable (Reachability rc)
5771 base.MarkReachable (rc);
5772 return Statement.MarkReachable (rc);
5775 public override bool Resolve (BlockContext bc)
5779 parent = bc.CurrentTryBlock;
5780 bc.CurrentTryBlock = this;
5782 using (bc.Set (ResolveContext.Options.TryScope)) {
5783 ok = stmt.Resolve (bc);
5786 bc.CurrentTryBlock = parent;
5789 // Finally block inside iterator is called from MoveNext and
5790 // Dispose methods that means we need to lift the block into
5791 // newly created host method to emit the body only once. The
5792 // original block then simply calls the newly generated method.
5794 if (bc.CurrentIterator != null && !bc.IsInProbingMode) {
5795 var b = stmt as Block;
5796 if (b != null && b.Explicit.HasYield) {
5797 finally_host = bc.CurrentIterator.CreateFinallyHost (this);
5801 return base.Resolve (bc) && ok;
5806 // Base class for blocks using exception handling
5808 public abstract class ExceptionStatement : ResumableStatement
5810 protected List<ResumableStatement> resume_points;
5811 protected int first_resume_pc;
5812 protected ExceptionStatement parent;
5814 protected ExceptionStatement (Location loc)
5819 protected virtual void EmitTryBodyPrepare (EmitContext ec)
5821 StateMachineInitializer state_machine = null;
5822 if (resume_points != null) {
5823 state_machine = (StateMachineInitializer) ec.CurrentAnonymousMethod;
5825 ec.EmitInt ((int) IteratorStorey.State.Running);
5826 ec.Emit (OpCodes.Stloc, state_machine.CurrentPC);
5829 ec.BeginExceptionBlock ();
5831 if (resume_points != null) {
5832 ec.MarkLabel (resume_point);
5834 // For normal control flow, we want to fall-through the Switch
5835 // So, we use CurrentPC rather than the $PC field, and initialize it to an outside value above
5836 ec.Emit (OpCodes.Ldloc, state_machine.CurrentPC);
5837 ec.EmitInt (first_resume_pc);
5838 ec.Emit (OpCodes.Sub);
5840 Label[] labels = new Label[resume_points.Count];
5841 for (int i = 0; i < resume_points.Count; ++i)
5842 labels[i] = resume_points[i].PrepareForEmit (ec);
5843 ec.Emit (OpCodes.Switch, labels);
5847 public virtual int AddResumePoint (ResumableStatement stmt, int pc, StateMachineInitializer stateMachine)
5849 if (parent != null) {
5850 // TODO: MOVE to virtual TryCatch
5851 var tc = this as TryCatch;
5852 var s = tc != null && tc.IsTryCatchFinally ? stmt : this;
5854 pc = parent.AddResumePoint (s, pc, stateMachine);
5856 pc = stateMachine.AddResumePoint (this);
5859 if (resume_points == null) {
5860 resume_points = new List<ResumableStatement> ();
5861 first_resume_pc = pc;
5864 if (pc != first_resume_pc + resume_points.Count)
5865 throw new InternalErrorException ("missed an intervening AddResumePoint?");
5867 resume_points.Add (stmt);
5872 public class Lock : TryFinallyBlock
5875 TemporaryVariableReference expr_copy;
5876 TemporaryVariableReference lock_taken;
5878 public Lock (Expression expr, Statement stmt, Location loc)
5884 public Expression Expr {
5890 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
5892 expr.FlowAnalysis (fc);
5893 return base.DoFlowAnalysis (fc);
5896 public override bool Resolve (BlockContext ec)
5898 expr = expr.Resolve (ec);
5902 if (!TypeSpec.IsReferenceType (expr.Type)) {
5903 ec.Report.Error (185, loc,
5904 "`{0}' is not a reference type as required by the lock statement",
5905 expr.Type.GetSignatureForError ());
5908 if (expr.Type.IsGenericParameter) {
5909 expr = Convert.ImplicitTypeParameterConversion (expr, (TypeParameterSpec)expr.Type, ec.BuiltinTypes.Object);
5912 VariableReference lv = expr as VariableReference;
5915 locked = lv.IsLockedByStatement;
5916 lv.IsLockedByStatement = true;
5923 // Have to keep original lock value around to unlock same location
5924 // in the case of original value has changed or is null
5926 expr_copy = TemporaryVariableReference.Create (ec.BuiltinTypes.Object, ec.CurrentBlock, loc);
5927 expr_copy.Resolve (ec);
5930 // Ensure Monitor methods are available
5932 if (ResolvePredefinedMethods (ec) > 1) {
5933 lock_taken = TemporaryVariableReference.Create (ec.BuiltinTypes.Bool, ec.CurrentBlock, loc);
5934 lock_taken.Resolve (ec);
5937 using (ec.Set (ResolveContext.Options.LockScope)) {
5942 lv.IsLockedByStatement = locked;
5948 protected override void EmitTryBodyPrepare (EmitContext ec)
5950 expr_copy.EmitAssign (ec, expr);
5952 if (lock_taken != null) {
5954 // Initialize ref variable
5956 lock_taken.EmitAssign (ec, new BoolLiteral (ec.BuiltinTypes, false, loc));
5959 // Monitor.Enter (expr_copy)
5961 expr_copy.Emit (ec);
5962 ec.Emit (OpCodes.Call, ec.Module.PredefinedMembers.MonitorEnter.Get ());
5965 base.EmitTryBodyPrepare (ec);
5968 protected override void EmitTryBody (EmitContext ec)
5971 // Monitor.Enter (expr_copy, ref lock_taken)
5973 if (lock_taken != null) {
5974 expr_copy.Emit (ec);
5975 lock_taken.LocalInfo.CreateBuilder (ec);
5976 lock_taken.AddressOf (ec, AddressOp.Load);
5977 ec.Emit (OpCodes.Call, ec.Module.PredefinedMembers.MonitorEnter_v4.Get ());
5980 Statement.Emit (ec);
5983 public override void EmitFinallyBody (EmitContext ec)
5986 // if (lock_taken) Monitor.Exit (expr_copy)
5988 Label skip = ec.DefineLabel ();
5990 if (lock_taken != null) {
5991 lock_taken.Emit (ec);
5992 ec.Emit (OpCodes.Brfalse_S, skip);
5995 expr_copy.Emit (ec);
5996 var m = ec.Module.PredefinedMembers.MonitorExit.Resolve (loc);
5998 ec.Emit (OpCodes.Call, m);
6000 ec.MarkLabel (skip);
6003 int ResolvePredefinedMethods (ResolveContext rc)
6005 // Try 4.0 Monitor.Enter (object, ref bool) overload first
6006 var m = rc.Module.PredefinedMembers.MonitorEnter_v4.Get ();
6010 m = rc.Module.PredefinedMembers.MonitorEnter.Get ();
6014 rc.Module.PredefinedMembers.MonitorEnter_v4.Resolve (loc);
6018 protected override void CloneTo (CloneContext clonectx, Statement t)
6020 Lock target = (Lock) t;
6022 target.expr = expr.Clone (clonectx);
6023 target.stmt = Statement.Clone (clonectx);
6026 public override object Accept (StructuralVisitor visitor)
6028 return visitor.Visit (this);
6033 public class Unchecked : Statement {
6036 public Unchecked (Block b, Location loc)
6043 public override bool Resolve (BlockContext ec)
6045 using (ec.With (ResolveContext.Options.AllCheckStateFlags, false))
6046 return Block.Resolve (ec);
6049 protected override void DoEmit (EmitContext ec)
6051 using (ec.With (EmitContext.Options.CheckedScope, false))
6055 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6057 return Block.FlowAnalysis (fc);
6060 public override Reachability MarkReachable (Reachability rc)
6062 base.MarkReachable (rc);
6063 return Block.MarkReachable (rc);
6066 protected override void CloneTo (CloneContext clonectx, Statement t)
6068 Unchecked target = (Unchecked) t;
6070 target.Block = clonectx.LookupBlock (Block);
6073 public override object Accept (StructuralVisitor visitor)
6075 return visitor.Visit (this);
6079 public class Checked : Statement {
6082 public Checked (Block b, Location loc)
6085 b.Unchecked = false;
6089 public override bool Resolve (BlockContext ec)
6091 using (ec.With (ResolveContext.Options.AllCheckStateFlags, true))
6092 return Block.Resolve (ec);
6095 protected override void DoEmit (EmitContext ec)
6097 using (ec.With (EmitContext.Options.CheckedScope, true))
6101 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6103 return Block.FlowAnalysis (fc);
6106 public override Reachability MarkReachable (Reachability rc)
6108 base.MarkReachable (rc);
6109 return Block.MarkReachable (rc);
6112 protected override void CloneTo (CloneContext clonectx, Statement t)
6114 Checked target = (Checked) t;
6116 target.Block = clonectx.LookupBlock (Block);
6119 public override object Accept (StructuralVisitor visitor)
6121 return visitor.Visit (this);
6125 public class Unsafe : Statement {
6128 public Unsafe (Block b, Location loc)
6131 Block.Unsafe = true;
6135 public override bool Resolve (BlockContext ec)
6137 if (ec.CurrentIterator != null)
6138 ec.Report.Error (1629, loc, "Unsafe code may not appear in iterators");
6140 using (ec.Set (ResolveContext.Options.UnsafeScope))
6141 return Block.Resolve (ec);
6144 protected override void DoEmit (EmitContext ec)
6149 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6151 return Block.FlowAnalysis (fc);
6154 public override Reachability MarkReachable (Reachability rc)
6156 base.MarkReachable (rc);
6157 return Block.MarkReachable (rc);
6160 protected override void CloneTo (CloneContext clonectx, Statement t)
6162 Unsafe target = (Unsafe) t;
6164 target.Block = clonectx.LookupBlock (Block);
6167 public override object Accept (StructuralVisitor visitor)
6169 return visitor.Visit (this);
6176 public class Fixed : Statement
6178 abstract class Emitter : ShimExpression
6180 protected LocalVariable vi;
6182 protected Emitter (Expression expr, LocalVariable li)
6188 public abstract void EmitExit (EmitContext ec);
6190 public override void FlowAnalysis (FlowAnalysisContext fc)
6192 expr.FlowAnalysis (fc);
6196 class ExpressionEmitter : Emitter {
6197 public ExpressionEmitter (Expression converted, LocalVariable li) :
6198 base (converted, li)
6202 protected override Expression DoResolve (ResolveContext rc)
6204 throw new NotImplementedException ();
6207 public override void Emit (EmitContext ec) {
6209 // Store pointer in pinned location
6215 public override void EmitExit (EmitContext ec)
6218 ec.Emit (OpCodes.Conv_U);
6223 class StringEmitter : Emitter
6225 LocalVariable pinned_string;
6227 public StringEmitter (Expression expr, LocalVariable li)
6232 protected override Expression DoResolve (ResolveContext rc)
6234 pinned_string = new LocalVariable (vi.Block, "$pinned",
6235 LocalVariable.Flags.FixedVariable | LocalVariable.Flags.CompilerGenerated | LocalVariable.Flags.Used,
6237 pinned_string.Type = rc.BuiltinTypes.String;
6239 eclass = ExprClass.Variable;
6240 type = rc.BuiltinTypes.Int;
6244 public override void Emit (EmitContext ec)
6246 pinned_string.CreateBuilder (ec);
6249 pinned_string.EmitAssign (ec);
6251 // TODO: Should use Binary::Add
6252 pinned_string.Emit (ec);
6253 ec.Emit (OpCodes.Conv_I);
6255 var m = ec.Module.PredefinedMembers.RuntimeHelpersOffsetToStringData.Resolve (loc);
6259 PropertyExpr pe = new PropertyExpr (m, pinned_string.Location);
6260 //pe.InstanceExpression = pinned_string;
6261 pe.Resolve (new ResolveContext (ec.MemberContext)).Emit (ec);
6263 ec.Emit (OpCodes.Add);
6267 public override void EmitExit (EmitContext ec)
6270 pinned_string.EmitAssign (ec);
6274 public class VariableDeclaration : BlockVariable
6276 public VariableDeclaration (FullNamedExpression type, LocalVariable li)
6281 protected override Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
6283 if (!Variable.Type.IsPointer && li == Variable) {
6284 bc.Report.Error (209, TypeExpression.Location,
6285 "The type of locals declared in a fixed statement must be a pointer type");
6290 // The rules for the possible declarators are pretty wise,
6291 // but the production on the grammar is more concise.
6293 // So we have to enforce these rules here.
6295 // We do not resolve before doing the case 1 test,
6296 // because the grammar is explicit in that the token &
6297 // is present, so we need to test for this particular case.
6300 if (initializer is Cast) {
6301 bc.Report.Error (254, initializer.Location, "The right hand side of a fixed statement assignment may not be a cast expression");
6305 initializer = initializer.Resolve (bc);
6307 if (initializer == null)
6313 if (initializer.Type.IsArray) {
6314 TypeSpec array_type = TypeManager.GetElementType (initializer.Type);
6317 // Provided that array_type is unmanaged,
6319 if (!TypeManager.VerifyUnmanaged (bc.Module, array_type, loc))
6323 // and T* is implicitly convertible to the
6324 // pointer type given in the fixed statement.
6326 ArrayPtr array_ptr = new ArrayPtr (initializer, array_type, loc);
6328 Expression converted = Convert.ImplicitConversionRequired (bc, array_ptr.Resolve (bc), li.Type, loc);
6329 if (converted == null)
6333 // fixed (T* e_ptr = (e == null || e.Length == 0) ? null : converted [0])
6335 converted = new Conditional (new BooleanExpression (new Binary (Binary.Operator.LogicalOr,
6336 new Binary (Binary.Operator.Equality, initializer, new NullLiteral (loc)),
6337 new Binary (Binary.Operator.Equality, new MemberAccess (initializer, "Length"), new IntConstant (bc.BuiltinTypes, 0, loc)))),
6338 new NullLiteral (loc),
6341 converted = converted.Resolve (bc);
6343 return new ExpressionEmitter (converted, li);
6349 if (initializer.Type.BuiltinType == BuiltinTypeSpec.Type.String) {
6350 return new StringEmitter (initializer, li).Resolve (bc);
6353 // Case 3: fixed buffer
6354 if (initializer is FixedBufferPtr) {
6355 return new ExpressionEmitter (initializer, li);
6359 // Case 4: & object.
6361 bool already_fixed = true;
6362 Unary u = initializer as Unary;
6363 if (u != null && u.Oper == Unary.Operator.AddressOf) {
6364 IVariableReference vr = u.Expr as IVariableReference;
6365 if (vr == null || !vr.IsFixed) {
6366 already_fixed = false;
6370 if (already_fixed) {
6371 bc.Report.Error (213, loc, "You cannot use the fixed statement to take the address of an already fixed expression");
6374 initializer = Convert.ImplicitConversionRequired (bc, initializer, li.Type, loc);
6375 return new ExpressionEmitter (initializer, li);
6380 VariableDeclaration decl;
6381 Statement statement;
6384 public Fixed (VariableDeclaration decl, Statement stmt, Location l)
6393 public Statement Statement {
6399 public BlockVariable Variables {
6407 public override bool Resolve (BlockContext bc)
6409 using (bc.Set (ResolveContext.Options.FixedInitializerScope)) {
6410 if (!decl.Resolve (bc))
6414 return statement.Resolve (bc);
6417 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6419 decl.FlowAnalysis (fc);
6420 return statement.FlowAnalysis (fc);
6423 protected override void DoEmit (EmitContext ec)
6425 decl.Variable.CreateBuilder (ec);
6426 decl.Initializer.Emit (ec);
6427 if (decl.Declarators != null) {
6428 foreach (var d in decl.Declarators) {
6429 d.Variable.CreateBuilder (ec);
6430 d.Initializer.Emit (ec);
6434 statement.Emit (ec);
6440 // Clear the pinned variable
6442 ((Emitter) decl.Initializer).EmitExit (ec);
6443 if (decl.Declarators != null) {
6444 foreach (var d in decl.Declarators) {
6445 ((Emitter)d.Initializer).EmitExit (ec);
6450 public override Reachability MarkReachable (Reachability rc)
6452 base.MarkReachable (rc);
6454 decl.MarkReachable (rc);
6456 rc = statement.MarkReachable (rc);
6458 // TODO: What if there is local exit?
6459 has_ret = rc.IsUnreachable;
6463 protected override void CloneTo (CloneContext clonectx, Statement t)
6465 Fixed target = (Fixed) t;
6467 target.decl = (VariableDeclaration) decl.Clone (clonectx);
6468 target.statement = statement.Clone (clonectx);
6471 public override object Accept (StructuralVisitor visitor)
6473 return visitor.Visit (this);
6477 public class Catch : Statement
6479 class FilterStatement : Statement
6481 readonly Catch ctch;
6483 public FilterStatement (Catch ctch)
6488 protected override void CloneTo (CloneContext clonectx, Statement target)
6492 protected override void DoEmit (EmitContext ec)
6494 if (ctch.li != null) {
6495 if (ctch.hoisted_temp != null)
6496 ctch.hoisted_temp.Emit (ec);
6500 if (!ctch.IsGeneral && ctch.type.Kind == MemberKind.TypeParameter)
6501 ec.Emit (OpCodes.Box, ctch.type);
6504 var expr_start = ec.DefineLabel ();
6505 var end = ec.DefineLabel ();
6507 ec.Emit (OpCodes.Brtrue_S, expr_start);
6509 ec.Emit (OpCodes.Br, end);
6510 ec.MarkLabel (expr_start);
6512 ctch.Filter.Emit (ec);
6515 ec.Emit (OpCodes.Endfilter);
6516 ec.BeginFilterHandler ();
6517 ec.Emit (OpCodes.Pop);
6520 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6522 ctch.Filter.FlowAnalysis (fc);
6526 public override bool Resolve (BlockContext bc)
6528 ctch.Filter = ctch.Filter.Resolve (bc);
6530 if (ctch.Filter != null) {
6531 if (ctch.Filter.ContainsEmitWithAwait ()) {
6532 bc.Report.Error (7094, ctch.Filter.Location, "The `await' operator cannot be used in the filter expression of a catch clause");
6535 var c = ctch.Filter as Constant;
6536 if (c != null && !c.IsDefaultValue) {
6537 bc.Report.Warning (7095, 1, ctch.Filter.Location, "Exception filter expression is a constant");
6545 ExplicitBlock block;
6547 FullNamedExpression type_expr;
6548 CompilerAssign assign;
6550 LocalTemporary hoisted_temp;
6552 public Catch (ExplicitBlock block, Location loc)
6560 public ExplicitBlock Block {
6566 public TypeSpec CatchType {
6572 public Expression Filter {
6576 public bool IsGeneral {
6578 return type_expr == null;
6582 public FullNamedExpression TypeExpression {
6591 public LocalVariable Variable {
6602 protected override void DoEmit (EmitContext ec)
6604 if (Filter != null) {
6605 ec.BeginExceptionFilterBlock ();
6606 ec.Emit (OpCodes.Isinst, IsGeneral ? ec.BuiltinTypes.Object : CatchType);
6609 EmitCatchVariableStore (ec);
6611 if (Block.HasAwait) {
6612 Block.EmitScopeInitialization (ec);
6621 ec.BeginCatchBlock (ec.BuiltinTypes.Object);
6623 ec.BeginCatchBlock (CatchType);
6626 EmitCatchVariableStore (ec);
6628 ec.Emit (OpCodes.Pop);
6631 if (!Block.HasAwait)
6635 void EmitCatchVariableStore (EmitContext ec)
6637 li.CreateBuilder (ec);
6640 // Special case hoisted catch variable, we have to use a temporary variable
6641 // to pass via anonymous storey initialization with the value still on top
6644 if (li.HoistedVariant != null) {
6645 hoisted_temp = new LocalTemporary (li.Type);
6646 hoisted_temp.Store (ec);
6648 // switch to assignment from temporary variable and not from top of the stack
6649 assign.UpdateSource (hoisted_temp);
6653 public override bool Resolve (BlockContext bc)
6655 using (bc.Set (ResolveContext.Options.CatchScope)) {
6656 if (type_expr == null) {
6657 if (CreateExceptionVariable (bc.Module.Compiler.BuiltinTypes.Object)) {
6658 Expression source = new EmptyExpression (li.Type);
6659 assign = new CompilerAssign (new LocalVariableReference (li, Location.Null), source, Location.Null);
6660 Block.AddScopeStatement (new StatementExpression (assign, Location.Null));
6663 type = type_expr.ResolveAsType (bc);
6668 CreateExceptionVariable (type);
6670 if (type.BuiltinType != BuiltinTypeSpec.Type.Exception && !TypeSpec.IsBaseClass (type, bc.BuiltinTypes.Exception, false)) {
6671 bc.Report.Error (155, loc, "The type caught or thrown must be derived from System.Exception");
6672 } else if (li != null) {
6674 li.PrepareAssignmentAnalysis (bc);
6676 // source variable is at the top of the stack
6677 Expression source = new EmptyExpression (li.Type);
6678 if (li.Type.IsGenericParameter)
6679 source = new UnboxCast (source, li.Type);
6682 // Uses Location.Null to hide from symbol file
6684 assign = new CompilerAssign (new LocalVariableReference (li, Location.Null), source, Location.Null);
6685 Block.AddScopeStatement (new StatementExpression (assign, Location.Null));
6689 if (Filter != null) {
6690 Block.AddScopeStatement (new FilterStatement (this));
6693 Block.SetCatchBlock ();
6694 return Block.Resolve (bc);
6698 bool CreateExceptionVariable (TypeSpec type)
6700 if (!Block.HasAwait)
6703 // TODO: Scan the block for rethrow expression
6704 //if (!Block.HasRethrow)
6707 li = LocalVariable.CreateCompilerGenerated (type, block, Location.Null);
6711 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6713 if (li != null && !li.IsCompilerGenerated) {
6714 fc.SetVariableAssigned (li.VariableInfo, true);
6717 return block.FlowAnalysis (fc);
6720 public override Reachability MarkReachable (Reachability rc)
6722 base.MarkReachable (rc);
6724 var c = Filter as Constant;
6725 if (c != null && c.IsDefaultValue)
6726 return Reachability.CreateUnreachable ();
6728 return block.MarkReachable (rc);
6731 protected override void CloneTo (CloneContext clonectx, Statement t)
6733 Catch target = (Catch) t;
6735 if (type_expr != null)
6736 target.type_expr = (FullNamedExpression) type_expr.Clone (clonectx);
6739 target.Filter = Filter.Clone (clonectx);
6741 target.block = (ExplicitBlock) clonectx.LookupBlock (block);
6745 public class TryFinally : TryFinallyBlock
6748 List<DefiniteAssignmentBitSet> try_exit_dat;
6749 List<Label> redirected_jumps;
6750 Label? start_fin_label;
6752 public TryFinally (Statement stmt, ExplicitBlock fini, Location loc)
6758 public ExplicitBlock FinallyBlock {
6764 public void RegisterForControlExitCheck (DefiniteAssignmentBitSet vector)
6766 if (try_exit_dat == null)
6767 try_exit_dat = new List<DefiniteAssignmentBitSet> ();
6769 try_exit_dat.Add (vector);
6772 public override bool Resolve (BlockContext bc)
6774 bool ok = base.Resolve (bc);
6776 fini.SetFinallyBlock ();
6777 using (bc.Set (ResolveContext.Options.FinallyScope)) {
6778 ok &= fini.Resolve (bc);
6784 protected override void EmitTryBody (EmitContext ec)
6786 if (fini.HasAwait) {
6787 if (ec.TryFinallyUnwind == null)
6788 ec.TryFinallyUnwind = new List<TryFinally> ();
6790 ec.TryFinallyUnwind.Add (this);
6792 ec.TryFinallyUnwind.Remove (this);
6794 if (start_fin_label != null)
6795 ec.MarkLabel (start_fin_label.Value);
6803 protected override bool EmitBeginFinallyBlock (EmitContext ec)
6808 return base.EmitBeginFinallyBlock (ec);
6811 public override void EmitFinallyBody (EmitContext ec)
6813 if (!fini.HasAwait) {
6819 // Emits catch block like
6821 // catch (object temp) {
6822 // this.exception_field = temp;
6825 var type = ec.BuiltinTypes.Object;
6826 ec.BeginCatchBlock (type);
6828 var temp = ec.GetTemporaryLocal (type);
6829 ec.Emit (OpCodes.Stloc, temp);
6831 var exception_field = ec.GetTemporaryField (type);
6833 ec.Emit (OpCodes.Ldloc, temp);
6834 exception_field.EmitAssignFromStack (ec);
6836 ec.EndExceptionBlock ();
6838 ec.FreeTemporaryLocal (temp, type);
6843 // Emits exception rethrow
6845 // if (this.exception_field != null)
6846 // throw this.exception_field;
6848 exception_field.Emit (ec);
6849 var skip_throw = ec.DefineLabel ();
6850 ec.Emit (OpCodes.Brfalse_S, skip_throw);
6851 exception_field.Emit (ec);
6852 ec.Emit (OpCodes.Throw);
6853 ec.MarkLabel (skip_throw);
6855 exception_field.IsAvailableForReuse = true;
6857 EmitUnwindFinallyTable (ec);
6860 bool IsParentBlock (Block block)
6862 for (Block b = fini; b != null; b = b.Parent) {
6870 public static Label EmitRedirectedJump (EmitContext ec, AsyncInitializer initializer, Label label, Block labelBlock)
6873 if (labelBlock != null) {
6874 for (idx = ec.TryFinallyUnwind.Count; idx != 0; --idx) {
6875 var fin = ec.TryFinallyUnwind [idx - 1];
6876 if (!fin.IsParentBlock (labelBlock))
6883 bool set_return_state = true;
6885 for (; idx < ec.TryFinallyUnwind.Count; ++idx) {
6886 var fin = ec.TryFinallyUnwind [idx];
6887 if (labelBlock != null && !fin.IsParentBlock (labelBlock))
6890 fin.EmitRedirectedExit (ec, label, initializer, set_return_state);
6891 set_return_state = false;
6893 if (fin.start_fin_label == null) {
6894 fin.start_fin_label = ec.DefineLabel ();
6897 label = fin.start_fin_label.Value;
6903 public static Label EmitRedirectedReturn (EmitContext ec, AsyncInitializer initializer)
6905 return EmitRedirectedJump (ec, initializer, initializer.BodyEnd, null);
6908 void EmitRedirectedExit (EmitContext ec, Label label, AsyncInitializer initializer, bool setReturnState)
6910 if (redirected_jumps == null) {
6911 redirected_jumps = new List<Label> ();
6913 // Add fallthrough label
6914 redirected_jumps.Add (ec.DefineLabel ());
6917 initializer.HoistedReturnState = ec.GetTemporaryField (ec.Module.Compiler.BuiltinTypes.Int, true);
6920 int index = redirected_jumps.IndexOf (label);
6922 redirected_jumps.Add (label);
6923 index = redirected_jumps.Count - 1;
6927 // Indicates we have captured exit jump
6929 if (setReturnState) {
6930 var value = new IntConstant (initializer.HoistedReturnState.Type, index, Location.Null);
6931 initializer.HoistedReturnState.EmitAssign (ec, value, false, false);
6936 // Emits state table of jumps outside of try block and reload of return
6937 // value when try block returns value
6939 void EmitUnwindFinallyTable (EmitContext ec)
6941 if (redirected_jumps == null)
6944 var initializer = (AsyncInitializer)ec.CurrentAnonymousMethod;
6945 initializer.HoistedReturnState.EmitLoad (ec);
6946 ec.Emit (OpCodes.Switch, redirected_jumps.ToArray ());
6948 // Mark fallthrough label
6949 ec.MarkLabel (redirected_jumps [0]);
6952 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
6954 var da = fc.BranchDefiniteAssignment ();
6956 var tf = fc.TryFinally;
6957 fc.TryFinally = this;
6959 var res_stmt = Statement.FlowAnalysis (fc);
6963 var try_da = fc.DefiniteAssignment;
6964 fc.DefiniteAssignment = da;
6966 var res_fin = fini.FlowAnalysis (fc);
6968 if (try_exit_dat != null) {
6970 // try block has global exit but we need to run definite assignment check
6971 // for parameter block out parameter after finally block because it's always
6972 // executed before exit
6974 foreach (var try_da_part in try_exit_dat)
6975 fc.ParametersBlock.CheckControlExit (fc, fc.DefiniteAssignment | try_da_part);
6977 try_exit_dat = null;
6980 fc.DefiniteAssignment |= try_da;
6981 return res_stmt | res_fin;
6984 public override Reachability MarkReachable (Reachability rc)
6987 // Mark finally block first for any exit statement in try block
6988 // to know whether the code which follows finally is reachable
6990 return fini.MarkReachable (rc) | base.MarkReachable (rc);
6993 protected override void CloneTo (CloneContext clonectx, Statement t)
6995 TryFinally target = (TryFinally) t;
6997 target.stmt = stmt.Clone (clonectx);
6999 target.fini = (ExplicitBlock) clonectx.LookupBlock (fini);
7002 public override object Accept (StructuralVisitor visitor)
7004 return visitor.Visit (this);
7008 public class TryCatch : ExceptionStatement
7011 List<Catch> clauses;
7012 readonly bool inside_try_finally;
7013 List<Catch> catch_sm;
7015 public TryCatch (Block block, List<Catch> catch_clauses, Location l, bool inside_try_finally)
7019 this.clauses = catch_clauses;
7020 this.inside_try_finally = inside_try_finally;
7023 public List<Catch> Clauses {
7029 public bool IsTryCatchFinally {
7031 return inside_try_finally;
7035 public override bool Resolve (BlockContext bc)
7039 using (bc.Set (ResolveContext.Options.TryScope)) {
7040 parent = bc.CurrentTryBlock;
7042 if (IsTryCatchFinally) {
7043 ok = Block.Resolve (bc);
7045 using (bc.Set (ResolveContext.Options.TryWithCatchScope)) {
7046 bc.CurrentTryBlock = this;
7047 ok = Block.Resolve (bc);
7048 bc.CurrentTryBlock = parent;
7053 for (int i = 0; i < clauses.Count; ++i) {
7056 ok &= c.Resolve (bc);
7058 if (c.Block.HasAwait) {
7059 if (catch_sm == null)
7060 catch_sm = new List<Catch> ();
7065 if (c.Filter != null)
7068 TypeSpec resolved_type = c.CatchType;
7069 if (resolved_type == null)
7072 for (int ii = 0; ii < clauses.Count; ++ii) {
7076 if (clauses[ii].Filter != null)
7079 if (clauses[ii].IsGeneral) {
7080 if (resolved_type.BuiltinType != BuiltinTypeSpec.Type.Exception)
7083 if (!bc.Module.DeclaringAssembly.WrapNonExceptionThrows)
7086 if (!bc.Module.PredefinedAttributes.RuntimeCompatibility.IsDefined)
7089 bc.Report.Warning (1058, 1, c.loc,
7090 "A previous catch clause already catches all exceptions. All non-exceptions thrown will be wrapped in a `System.Runtime.CompilerServices.RuntimeWrappedException'");
7098 var ct = clauses[ii].CatchType;
7102 if (resolved_type == ct || TypeSpec.IsBaseClass (resolved_type, ct, true)) {
7103 bc.Report.Error (160, c.loc,
7104 "A previous catch clause already catches all exceptions of this or a super type `{0}'",
7105 ct.GetSignatureForError ());
7111 return base.Resolve (bc) && ok;
7114 protected sealed override void DoEmit (EmitContext ec)
7116 if (!inside_try_finally)
7117 EmitTryBodyPrepare (ec);
7121 LocalBuilder state_variable = null;
7122 foreach (Catch c in clauses) {
7125 if (catch_sm != null) {
7126 if (state_variable == null) {
7128 // Cannot reuse temp variable because non-catch path assumes the value is 0
7129 // which may not be true for reused local variable
7131 state_variable = ec.DeclareLocal (ec.Module.Compiler.BuiltinTypes.Int, false);
7134 var index = catch_sm.IndexOf (c);
7138 ec.EmitInt (index + 1);
7139 ec.Emit (OpCodes.Stloc, state_variable);
7143 if (!inside_try_finally)
7144 ec.EndExceptionBlock ();
7146 if (state_variable != null) {
7147 ec.Emit (OpCodes.Ldloc, state_variable);
7149 var labels = new Label [catch_sm.Count + 1];
7150 for (int i = 0; i < labels.Length; ++i) {
7151 labels [i] = ec.DefineLabel ();
7154 var end = ec.DefineLabel ();
7155 ec.Emit (OpCodes.Switch, labels);
7157 // 0 value is default label
7158 ec.MarkLabel (labels [0]);
7159 ec.Emit (OpCodes.Br, end);
7161 var atv = ec.AsyncThrowVariable;
7163 for (int i = 0; i < catch_sm.Count; ++i) {
7164 if (c != null && c.Block.HasReachableClosingBrace)
7165 ec.Emit (OpCodes.Br, end);
7167 ec.MarkLabel (labels [i + 1]);
7169 ec.AsyncThrowVariable = c.Variable;
7172 ec.AsyncThrowVariable = atv;
7178 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7180 var start_fc = fc.BranchDefiniteAssignment ();
7181 var res = Block.FlowAnalysis (fc);
7183 DefiniteAssignmentBitSet try_fc = res ? null : fc.DefiniteAssignment;
7185 foreach (var c in clauses) {
7186 fc.DefiniteAssignment = new DefiniteAssignmentBitSet (start_fc);
7187 if (!c.FlowAnalysis (fc)) {
7189 try_fc = fc.DefiniteAssignment;
7191 try_fc &= fc.DefiniteAssignment;
7197 fc.DefiniteAssignment = try_fc ?? start_fc;
7202 public override Reachability MarkReachable (Reachability rc)
7204 if (rc.IsUnreachable)
7207 base.MarkReachable (rc);
7209 var tc_rc = Block.MarkReachable (rc);
7211 foreach (var c in clauses)
7212 tc_rc &= c.MarkReachable (rc);
7217 protected override void CloneTo (CloneContext clonectx, Statement t)
7219 TryCatch target = (TryCatch) t;
7221 target.Block = clonectx.LookupBlock (Block);
7222 if (clauses != null){
7223 target.clauses = new List<Catch> ();
7224 foreach (Catch c in clauses)
7225 target.clauses.Add ((Catch) c.Clone (clonectx));
7229 public override object Accept (StructuralVisitor visitor)
7231 return visitor.Visit (this);
7235 public class Using : TryFinallyBlock
7237 public class VariableDeclaration : BlockVariable
7239 Statement dispose_call;
7241 public VariableDeclaration (FullNamedExpression type, LocalVariable li)
7246 public VariableDeclaration (LocalVariable li, Location loc)
7253 public VariableDeclaration (Expression expr)
7256 loc = expr.Location;
7262 public bool IsNested { get; private set; }
7266 public void EmitDispose (EmitContext ec)
7268 dispose_call.Emit (ec);
7271 public override bool Resolve (BlockContext bc)
7276 return base.Resolve (bc, false);
7279 public Expression ResolveExpression (BlockContext bc)
7281 var e = Initializer.Resolve (bc);
7285 li = LocalVariable.CreateCompilerGenerated (e.Type, bc.CurrentBlock, loc);
7286 Initializer = ResolveInitializer (bc, Variable, e);
7290 protected override Expression ResolveInitializer (BlockContext bc, LocalVariable li, Expression initializer)
7292 if (li.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
7293 initializer = initializer.Resolve (bc);
7294 if (initializer == null)
7297 // Once there is dynamic used defer conversion to runtime even if we know it will never succeed
7298 Arguments args = new Arguments (1);
7299 args.Add (new Argument (initializer));
7300 initializer = new DynamicConversion (bc.BuiltinTypes.IDisposable, 0, args, initializer.Location).Resolve (bc);
7301 if (initializer == null)
7304 var var = LocalVariable.CreateCompilerGenerated (initializer.Type, bc.CurrentBlock, loc);
7305 dispose_call = CreateDisposeCall (bc, var);
7306 dispose_call.Resolve (bc);
7308 return base.ResolveInitializer (bc, li, new SimpleAssign (var.CreateReferenceExpression (bc, loc), initializer, loc));
7311 if (li == Variable) {
7312 CheckIDiposableConversion (bc, li, initializer);
7313 dispose_call = CreateDisposeCall (bc, li);
7314 dispose_call.Resolve (bc);
7317 return base.ResolveInitializer (bc, li, initializer);
7320 protected virtual void CheckIDiposableConversion (BlockContext bc, LocalVariable li, Expression initializer)
7324 if (type.BuiltinType != BuiltinTypeSpec.Type.IDisposable && !CanConvertToIDisposable (bc, type)) {
7325 if (type.IsNullableType) {
7326 // it's handled in CreateDisposeCall
7330 if (type != InternalType.ErrorType) {
7331 bc.Report.SymbolRelatedToPreviousError (type);
7332 var loc = type_expr == null ? initializer.Location : type_expr.Location;
7333 bc.Report.Error (1674, loc, "`{0}': type used in a using statement must be implicitly convertible to `System.IDisposable'",
7334 type.GetSignatureForError ());
7341 static bool CanConvertToIDisposable (BlockContext bc, TypeSpec type)
7343 var target = bc.BuiltinTypes.IDisposable;
7344 var tp = type as TypeParameterSpec;
7346 return Convert.ImplicitTypeParameterConversion (null, tp, target) != null;
7348 return type.ImplementsInterface (target, false);
7351 protected virtual Statement CreateDisposeCall (BlockContext bc, LocalVariable lv)
7353 var lvr = lv.CreateReferenceExpression (bc, lv.Location);
7355 var loc = lv.Location;
7357 var idt = bc.BuiltinTypes.IDisposable;
7358 var m = bc.Module.PredefinedMembers.IDisposableDispose.Resolve (loc);
7360 var dispose_mg = MethodGroupExpr.CreatePredefined (m, idt, loc);
7361 dispose_mg.InstanceExpression = type.IsNullableType ?
7362 new Cast (new TypeExpression (idt, loc), lvr, loc).Resolve (bc) :
7366 // Hide it from symbol file via null location
7368 Statement dispose = new StatementExpression (new Invocation (dispose_mg, null), Location.Null);
7370 // Add conditional call when disposing possible null variable
7371 if (!TypeSpec.IsValueType (type) || type.IsNullableType)
7372 dispose = new If (new Binary (Binary.Operator.Inequality, lvr, new NullLiteral (loc)), dispose, dispose.loc);
7377 public void ResolveDeclaratorInitializer (BlockContext bc)
7379 Initializer = base.ResolveInitializer (bc, Variable, Initializer);
7382 public Statement RewriteUsingDeclarators (BlockContext bc, Statement stmt)
7384 for (int i = declarators.Count - 1; i >= 0; --i) {
7385 var d = declarators [i];
7386 var vd = new VariableDeclaration (d.Variable, d.Variable.Location);
7387 vd.Initializer = d.Initializer;
7389 vd.dispose_call = CreateDisposeCall (bc, d.Variable);
7390 vd.dispose_call.Resolve (bc);
7392 stmt = new Using (vd, stmt, d.Variable.Location);
7399 public override object Accept (StructuralVisitor visitor)
7401 return visitor.Visit (this);
7405 VariableDeclaration decl;
7407 public Using (VariableDeclaration decl, Statement stmt, Location loc)
7413 public Using (Expression expr, Statement stmt, Location loc)
7416 this.decl = new VariableDeclaration (expr);
7421 public Expression Expr {
7423 return decl.Variable == null ? decl.Initializer : null;
7427 public BlockVariable Variables {
7435 public override void Emit (EmitContext ec)
7438 // Don't emit sequence point it will be set on variable declaration
7443 protected override void EmitTryBodyPrepare (EmitContext ec)
7446 base.EmitTryBodyPrepare (ec);
7449 protected override void EmitTryBody (EmitContext ec)
7454 public override void EmitFinallyBody (EmitContext ec)
7456 decl.EmitDispose (ec);
7459 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7461 decl.FlowAnalysis (fc);
7462 return stmt.FlowAnalysis (fc);
7465 public override Reachability MarkReachable (Reachability rc)
7467 decl.MarkReachable (rc);
7468 return base.MarkReachable (rc);
7471 public override bool Resolve (BlockContext ec)
7473 VariableReference vr;
7474 bool vr_locked = false;
7476 using (ec.Set (ResolveContext.Options.UsingInitializerScope)) {
7477 if (decl.Variable == null) {
7478 vr = decl.ResolveExpression (ec) as VariableReference;
7480 vr_locked = vr.IsLockedByStatement;
7481 vr.IsLockedByStatement = true;
7484 if (decl.IsNested) {
7485 decl.ResolveDeclaratorInitializer (ec);
7487 if (!decl.Resolve (ec))
7490 if (decl.Declarators != null) {
7491 stmt = decl.RewriteUsingDeclarators (ec, stmt);
7499 var ok = base.Resolve (ec);
7502 vr.IsLockedByStatement = vr_locked;
7507 protected override void CloneTo (CloneContext clonectx, Statement t)
7509 Using target = (Using) t;
7511 target.decl = (VariableDeclaration) decl.Clone (clonectx);
7512 target.stmt = stmt.Clone (clonectx);
7515 public override object Accept (StructuralVisitor visitor)
7517 return visitor.Visit (this);
7522 /// Implementation of the foreach C# statement
7524 public class Foreach : LoopStatement
7526 abstract class IteratorStatement : Statement
7528 protected readonly Foreach for_each;
7530 protected IteratorStatement (Foreach @foreach)
7532 this.for_each = @foreach;
7533 this.loc = @foreach.expr.Location;
7536 protected override void CloneTo (CloneContext clonectx, Statement target)
7538 throw new NotImplementedException ();
7541 public override void Emit (EmitContext ec)
7543 if (ec.EmitAccurateDebugInfo) {
7544 ec.Emit (OpCodes.Nop);
7550 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
7552 throw new NotImplementedException ();
7556 sealed class ArrayForeach : IteratorStatement
7558 TemporaryVariableReference[] lengths;
7559 Expression [] length_exprs;
7560 StatementExpression[] counter;
7561 TemporaryVariableReference[] variables;
7563 TemporaryVariableReference copy;
7565 public ArrayForeach (Foreach @foreach, int rank)
7568 counter = new StatementExpression[rank];
7569 variables = new TemporaryVariableReference[rank];
7570 length_exprs = new Expression [rank];
7573 // Only use temporary length variables when dealing with
7574 // multi-dimensional arrays
7577 lengths = new TemporaryVariableReference [rank];
7580 public override bool Resolve (BlockContext ec)
7582 Block variables_block = for_each.variable.Block;
7583 copy = TemporaryVariableReference.Create (for_each.expr.Type, variables_block, loc);
7586 int rank = length_exprs.Length;
7587 Arguments list = new Arguments (rank);
7588 for (int i = 0; i < rank; i++) {
7589 var v = TemporaryVariableReference.Create (ec.BuiltinTypes.Int, variables_block, loc);
7591 counter[i] = new StatementExpression (new UnaryMutator (UnaryMutator.Mode.PostIncrement, v, Location.Null));
7592 counter[i].Resolve (ec);
7595 length_exprs [i] = new MemberAccess (copy, "Length").Resolve (ec);
7597 lengths[i] = TemporaryVariableReference.Create (ec.BuiltinTypes.Int, variables_block, loc);
7598 lengths[i].Resolve (ec);
7600 Arguments args = new Arguments (1);
7601 args.Add (new Argument (new IntConstant (ec.BuiltinTypes, i, loc)));
7602 length_exprs [i] = new Invocation (new MemberAccess (copy, "GetLength"), args).Resolve (ec);
7605 list.Add (new Argument (v));
7608 var access = new ElementAccess (copy, list, loc).Resolve (ec);
7613 if (for_each.type is VarExpr) {
7614 // Infer implicitly typed local variable from foreach array type
7615 var_type = access.Type;
7617 var_type = for_each.type.ResolveAsType (ec);
7619 if (var_type == null)
7622 access = Convert.ExplicitConversion (ec, access, var_type, loc);
7627 for_each.variable.Type = var_type;
7629 var variable_ref = new LocalVariableReference (for_each.variable, loc).Resolve (ec);
7630 if (variable_ref == null)
7633 for_each.body.AddScopeStatement (new StatementExpression (new CompilerAssign (variable_ref, access, Location.Null), for_each.type.Location));
7635 return for_each.body.Resolve (ec);
7638 protected override void DoEmit (EmitContext ec)
7640 copy.EmitAssign (ec, for_each.expr);
7642 int rank = length_exprs.Length;
7643 Label[] test = new Label [rank];
7644 Label[] loop = new Label [rank];
7646 for (int i = 0; i < rank; i++) {
7647 test [i] = ec.DefineLabel ();
7648 loop [i] = ec.DefineLabel ();
7650 if (lengths != null)
7651 lengths [i].EmitAssign (ec, length_exprs [i]);
7654 IntConstant zero = new IntConstant (ec.BuiltinTypes, 0, loc);
7655 for (int i = 0; i < rank; i++) {
7656 variables [i].EmitAssign (ec, zero);
7658 ec.Emit (OpCodes.Br, test [i]);
7659 ec.MarkLabel (loop [i]);
7662 for_each.body.Emit (ec);
7664 ec.MarkLabel (ec.LoopBegin);
7665 ec.Mark (for_each.expr.Location);
7667 for (int i = rank - 1; i >= 0; i--){
7668 counter [i].Emit (ec);
7670 ec.MarkLabel (test [i]);
7671 variables [i].Emit (ec);
7673 if (lengths != null)
7674 lengths [i].Emit (ec);
7676 length_exprs [i].Emit (ec);
7678 ec.Emit (OpCodes.Blt, loop [i]);
7681 ec.MarkLabel (ec.LoopEnd);
7685 sealed class CollectionForeach : IteratorStatement, OverloadResolver.IErrorHandler
7687 class RuntimeDispose : Using.VariableDeclaration
7689 public RuntimeDispose (LocalVariable lv, Location loc)
7695 protected override void CheckIDiposableConversion (BlockContext bc, LocalVariable li, Expression initializer)
7697 // Defered to runtime check
7700 protected override Statement CreateDisposeCall (BlockContext bc, LocalVariable lv)
7702 var idt = bc.BuiltinTypes.IDisposable;
7705 // Fabricates code like
7707 // if ((temp = vr as IDisposable) != null) temp.Dispose ();
7710 var dispose_variable = LocalVariable.CreateCompilerGenerated (idt, bc.CurrentBlock, loc);
7712 var idisaposable_test = new Binary (Binary.Operator.Inequality, new CompilerAssign (
7713 dispose_variable.CreateReferenceExpression (bc, loc),
7714 new As (lv.CreateReferenceExpression (bc, loc), new TypeExpression (dispose_variable.Type, loc), loc),
7715 loc), new NullLiteral (loc));
7717 var m = bc.Module.PredefinedMembers.IDisposableDispose.Resolve (loc);
7719 var dispose_mg = MethodGroupExpr.CreatePredefined (m, idt, loc);
7720 dispose_mg.InstanceExpression = dispose_variable.CreateReferenceExpression (bc, loc);
7722 Statement dispose = new StatementExpression (new Invocation (dispose_mg, null));
7723 return new If (idisaposable_test, dispose, loc);
7727 LocalVariable variable;
7729 Statement statement;
7730 ExpressionStatement init;
7731 TemporaryVariableReference enumerator_variable;
7732 bool ambiguous_getenumerator_name;
7734 public CollectionForeach (Foreach @foreach, LocalVariable var, Expression expr)
7737 this.variable = var;
7741 void Error_WrongEnumerator (ResolveContext rc, MethodSpec enumerator)
7743 rc.Report.SymbolRelatedToPreviousError (enumerator);
7744 rc.Report.Error (202, loc,
7745 "foreach statement requires that the return type `{0}' of `{1}' must have a suitable public MoveNext method and public Current property",
7746 enumerator.ReturnType.GetSignatureForError (), enumerator.GetSignatureForError ());
7749 MethodGroupExpr ResolveGetEnumerator (ResolveContext rc)
7752 // Option 1: Try to match by name GetEnumerator first
7754 var mexpr = Expression.MemberLookup (rc, false, expr.Type,
7755 "GetEnumerator", 0, Expression.MemberLookupRestrictions.ExactArity, loc); // TODO: What if CS0229 ?
7757 var mg = mexpr as MethodGroupExpr;
7759 mg.InstanceExpression = expr;
7760 Arguments args = new Arguments (0);
7761 mg = mg.OverloadResolve (rc, ref args, this, OverloadResolver.Restrictions.ProbingOnly | OverloadResolver.Restrictions.GetEnumeratorLookup);
7763 // For ambiguous GetEnumerator name warning CS0278 was reported, but Option 2 could still apply
7764 if (ambiguous_getenumerator_name)
7767 if (mg != null && !mg.BestCandidate.IsStatic && mg.BestCandidate.IsPublic) {
7773 // Option 2: Try to match using IEnumerable interfaces with preference of generic version
7776 PredefinedMember<MethodSpec> iface_candidate = null;
7777 var ptypes = rc.Module.PredefinedTypes;
7778 var gen_ienumerable = ptypes.IEnumerableGeneric;
7779 if (!gen_ienumerable.Define ())
7780 gen_ienumerable = null;
7782 var ifaces = t.Interfaces;
7783 if (ifaces != null) {
7784 foreach (var iface in ifaces) {
7785 if (gen_ienumerable != null && iface.MemberDefinition == gen_ienumerable.TypeSpec.MemberDefinition) {
7786 if (iface_candidate != null && iface_candidate != rc.Module.PredefinedMembers.IEnumerableGetEnumerator) {
7787 rc.Report.SymbolRelatedToPreviousError (expr.Type);
7788 rc.Report.Error (1640, loc,
7789 "foreach statement cannot operate on variables of type `{0}' because it contains multiple implementation of `{1}'. Try casting to a specific implementation",
7790 expr.Type.GetSignatureForError (), gen_ienumerable.TypeSpec.GetSignatureForError ());
7795 // TODO: Cache this somehow
7796 iface_candidate = new PredefinedMember<MethodSpec> (rc.Module, iface,
7797 MemberFilter.Method ("GetEnumerator", 0, ParametersCompiled.EmptyReadOnlyParameters, null));
7802 if (iface.BuiltinType == BuiltinTypeSpec.Type.IEnumerable && iface_candidate == null) {
7803 iface_candidate = rc.Module.PredefinedMembers.IEnumerableGetEnumerator;
7808 if (iface_candidate == null) {
7809 if (expr.Type != InternalType.ErrorType) {
7810 rc.Report.Error (1579, loc,
7811 "foreach statement cannot operate on variables of type `{0}' because it does not contain a definition for `{1}' or is inaccessible",
7812 expr.Type.GetSignatureForError (), "GetEnumerator");
7818 var method = iface_candidate.Resolve (loc);
7822 mg = MethodGroupExpr.CreatePredefined (method, expr.Type, loc);
7823 mg.InstanceExpression = expr;
7827 MethodGroupExpr ResolveMoveNext (ResolveContext rc, MethodSpec enumerator)
7829 var ms = MemberCache.FindMember (enumerator.ReturnType,
7830 MemberFilter.Method ("MoveNext", 0, ParametersCompiled.EmptyReadOnlyParameters, rc.BuiltinTypes.Bool),
7831 BindingRestriction.InstanceOnly) as MethodSpec;
7833 if (ms == null || !ms.IsPublic) {
7834 Error_WrongEnumerator (rc, enumerator);
7838 return MethodGroupExpr.CreatePredefined (ms, enumerator.ReturnType, expr.Location);
7841 PropertySpec ResolveCurrent (ResolveContext rc, MethodSpec enumerator)
7843 var ps = MemberCache.FindMember (enumerator.ReturnType,
7844 MemberFilter.Property ("Current", null),
7845 BindingRestriction.InstanceOnly) as PropertySpec;
7847 if (ps == null || !ps.IsPublic) {
7848 Error_WrongEnumerator (rc, enumerator);
7855 public override bool Resolve (BlockContext ec)
7857 bool is_dynamic = expr.Type.BuiltinType == BuiltinTypeSpec.Type.Dynamic;
7860 expr = Convert.ImplicitConversionRequired (ec, expr, ec.BuiltinTypes.IEnumerable, loc);
7861 } else if (expr.Type.IsNullableType) {
7862 expr = new Nullable.UnwrapCall (expr).Resolve (ec);
7865 var get_enumerator_mg = ResolveGetEnumerator (ec);
7866 if (get_enumerator_mg == null) {
7870 var get_enumerator = get_enumerator_mg.BestCandidate;
7871 enumerator_variable = TemporaryVariableReference.Create (get_enumerator.ReturnType, variable.Block, loc);
7872 enumerator_variable.Resolve (ec);
7874 // Prepare bool MoveNext ()
7875 var move_next_mg = ResolveMoveNext (ec, get_enumerator);
7876 if (move_next_mg == null) {
7880 move_next_mg.InstanceExpression = enumerator_variable;
7882 // Prepare ~T~ Current { get; }
7883 var current_prop = ResolveCurrent (ec, get_enumerator);
7884 if (current_prop == null) {
7888 var current_pe = new PropertyExpr (current_prop, loc) { InstanceExpression = enumerator_variable }.Resolve (ec);
7889 if (current_pe == null)
7892 VarExpr ve = for_each.type as VarExpr;
7896 // Source type is dynamic, set element type to dynamic too
7897 variable.Type = ec.BuiltinTypes.Dynamic;
7899 // Infer implicitly typed local variable from foreach enumerable type
7900 variable.Type = current_pe.Type;
7904 // Explicit cast of dynamic collection elements has to be done at runtime
7905 current_pe = EmptyCast.Create (current_pe, ec.BuiltinTypes.Dynamic);
7908 variable.Type = for_each.type.ResolveAsType (ec);
7910 if (variable.Type == null)
7913 current_pe = Convert.ExplicitConversion (ec, current_pe, variable.Type, loc);
7914 if (current_pe == null)
7918 var variable_ref = new LocalVariableReference (variable, loc).Resolve (ec);
7919 if (variable_ref == null)
7922 for_each.body.AddScopeStatement (new StatementExpression (new CompilerAssign (variable_ref, current_pe, Location.Null), for_each.type.Location));
7924 var init = new Invocation.Predefined (get_enumerator_mg, null);
7926 statement = new While (new BooleanExpression (new Invocation (move_next_mg, null)),
7927 for_each.body, Location.Null);
7929 var enum_type = enumerator_variable.Type;
7932 // Add Dispose method call when enumerator can be IDisposable
7934 if (!enum_type.ImplementsInterface (ec.BuiltinTypes.IDisposable, false)) {
7935 if (!enum_type.IsSealed && !TypeSpec.IsValueType (enum_type)) {
7937 // Runtime Dispose check
7939 var vd = new RuntimeDispose (enumerator_variable.LocalInfo, Location.Null);
7940 vd.Initializer = init;
7941 statement = new Using (vd, statement, Location.Null);
7944 // No Dispose call needed
7946 this.init = new SimpleAssign (enumerator_variable, init, Location.Null);
7947 this.init.Resolve (ec);
7951 // Static Dispose check
7953 var vd = new Using.VariableDeclaration (enumerator_variable.LocalInfo, Location.Null);
7954 vd.Initializer = init;
7955 statement = new Using (vd, statement, Location.Null);
7958 return statement.Resolve (ec);
7961 protected override void DoEmit (EmitContext ec)
7963 enumerator_variable.LocalInfo.CreateBuilder (ec);
7966 init.EmitStatement (ec);
7968 statement.Emit (ec);
7971 #region IErrorHandler Members
7973 bool OverloadResolver.IErrorHandler.AmbiguousCandidates (ResolveContext ec, MemberSpec best, MemberSpec ambiguous)
7975 ec.Report.SymbolRelatedToPreviousError (best);
7976 ec.Report.Warning (278, 2, expr.Location,
7977 "`{0}' contains ambiguous implementation of `{1}' pattern. Method `{2}' is ambiguous with method `{3}'",
7978 expr.Type.GetSignatureForError (), "enumerable",
7979 best.GetSignatureForError (), ambiguous.GetSignatureForError ());
7981 ambiguous_getenumerator_name = true;
7985 bool OverloadResolver.IErrorHandler.ArgumentMismatch (ResolveContext rc, MemberSpec best, Argument arg, int index)
7990 bool OverloadResolver.IErrorHandler.NoArgumentMatch (ResolveContext rc, MemberSpec best)
7995 bool OverloadResolver.IErrorHandler.TypeInferenceFailed (ResolveContext rc, MemberSpec best)
8004 LocalVariable variable;
8008 public Foreach (Expression type, LocalVariable var, Expression expr, Statement stmt, Block body, Location l)
8012 this.variable = var;
8018 public Expression Expr {
8019 get { return expr; }
8022 public Expression TypeExpression {
8023 get { return type; }
8026 public LocalVariable Variable {
8027 get { return variable; }
8030 public override Reachability MarkReachable (Reachability rc)
8032 base.MarkReachable (rc);
8034 body.MarkReachable (rc);
8039 public override bool Resolve (BlockContext ec)
8041 expr = expr.Resolve (ec);
8046 ec.Report.Error (186, loc, "Use of null is not valid in this context");
8050 body.AddStatement (Statement);
8052 if (expr.Type.BuiltinType == BuiltinTypeSpec.Type.String) {
8053 Statement = new ArrayForeach (this, 1);
8054 } else if (expr.Type is ArrayContainer) {
8055 Statement = new ArrayForeach (this, ((ArrayContainer) expr.Type).Rank);
8057 if (expr.eclass == ExprClass.MethodGroup || expr is AnonymousMethodExpression) {
8058 ec.Report.Error (446, expr.Location, "Foreach statement cannot operate on a `{0}'",
8059 expr.ExprClassName);
8063 Statement = new CollectionForeach (this, variable, expr);
8066 return base.Resolve (ec);
8069 protected override void DoEmit (EmitContext ec)
8071 Label old_begin = ec.LoopBegin, old_end = ec.LoopEnd;
8072 ec.LoopBegin = ec.DefineLabel ();
8073 ec.LoopEnd = ec.DefineLabel ();
8075 if (!(Statement is Block))
8076 ec.BeginCompilerScope ();
8078 variable.CreateBuilder (ec);
8080 Statement.Emit (ec);
8082 if (!(Statement is Block))
8085 ec.LoopBegin = old_begin;
8086 ec.LoopEnd = old_end;
8089 protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
8091 expr.FlowAnalysis (fc);
8093 var da = fc.BranchDefiniteAssignment ();
8094 body.FlowAnalysis (fc);
8095 fc.DefiniteAssignment = da;
8099 protected override void CloneTo (CloneContext clonectx, Statement t)
8101 Foreach target = (Foreach) t;
8103 target.type = type.Clone (clonectx);
8104 target.expr = expr.Clone (clonectx);
8105 target.body = (Block) body.Clone (clonectx);
8106 target.Statement = Statement.Clone (clonectx);
8109 public override object Accept (StructuralVisitor visitor)
8111 return visitor.Visit (this);