2 // statement.cs: Statement representation for the IL tree.
5 // Miguel de Icaza (miguel@ximian.com)
6 // Martin Baulig (martin@ximian.com)
8 // (C) 2001, 2002, 2003 Ximian, Inc.
9 // (C) 2003, 2004 Novell, Inc.
14 using System.Reflection;
15 using System.Reflection.Emit;
16 using System.Diagnostics;
17 using System.Collections;
18 using System.Collections.Specialized;
20 namespace Mono.CSharp {
22 public abstract class Statement {
26 /// Resolves the statement, true means that all sub-statements
29 public virtual bool Resolve (EmitContext ec)
35 /// We already know that the statement is unreachable, but we still
36 /// need to resolve it to catch errors.
38 public virtual bool ResolveUnreachable (EmitContext ec, bool warn)
41 // This conflicts with csc's way of doing this, but IMHO it's
42 // the right thing to do.
44 // If something is unreachable, we still check whether it's
45 // correct. This means that you cannot use unassigned variables
46 // in unreachable code, for instance.
49 if (warn && (RootContext.WarningLevel >= 2))
50 Report.Warning (162, loc, "Unreachable code detected");
52 ec.StartFlowBranching (FlowBranching.BranchingType.Block, loc);
53 bool ok = Resolve (ec);
54 ec.KillFlowBranching ();
60 /// Return value indicates whether all code paths emitted return.
62 protected abstract void DoEmit (EmitContext ec);
65 /// Utility wrapper routine for Error, just to beautify the code
67 public void Error (int error, string format, params object[] args)
69 Error (error, String.Format (format, args));
72 public void Error (int error, string s)
75 Report.Error (error, loc, s);
77 Report.Error (error, s);
81 /// Return value indicates whether all code paths emitted return.
83 public virtual void Emit (EmitContext ec)
90 public sealed class EmptyStatement : Statement {
92 private EmptyStatement () {}
94 public static readonly EmptyStatement Value = new EmptyStatement ();
96 public override bool Resolve (EmitContext ec)
101 protected override void DoEmit (EmitContext ec)
106 public class If : Statement {
108 public Statement TrueStatement;
109 public Statement FalseStatement;
113 public If (Expression expr, Statement trueStatement, Location l)
116 TrueStatement = trueStatement;
120 public If (Expression expr,
121 Statement trueStatement,
122 Statement falseStatement,
126 TrueStatement = trueStatement;
127 FalseStatement = falseStatement;
131 public override bool Resolve (EmitContext ec)
135 Report.Debug (1, "START IF BLOCK", loc);
137 expr = Expression.ResolveBoolean (ec, expr, loc);
143 Assign ass = expr as Assign;
144 if (ass != null && ass.Source is Constant) {
145 Report.Warning (665, 3, loc, "Assignment in conditional expression is always constant; did you mean to use == instead of = ?");
149 // Dead code elimination
151 if (expr is BoolConstant){
152 bool take = ((BoolConstant) expr).Value;
155 if (!TrueStatement.Resolve (ec))
158 if ((FalseStatement != null) &&
159 !FalseStatement.ResolveUnreachable (ec, true))
161 FalseStatement = null;
163 if (!TrueStatement.ResolveUnreachable (ec, true))
165 TrueStatement = null;
167 if ((FalseStatement != null) &&
168 !FalseStatement.Resolve (ec))
175 ec.StartFlowBranching (FlowBranching.BranchingType.Conditional, loc);
177 ok &= TrueStatement.Resolve (ec);
179 is_true_ret = ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable;
181 ec.CurrentBranching.CreateSibling ();
183 if (FalseStatement != null)
184 ok &= FalseStatement.Resolve (ec);
186 ec.EndFlowBranching ();
188 Report.Debug (1, "END IF BLOCK", loc);
193 protected override void DoEmit (EmitContext ec)
195 ILGenerator ig = ec.ig;
196 Label false_target = ig.DefineLabel ();
200 // If we're a boolean expression, Resolve() already
201 // eliminated dead code for us.
203 if (expr is BoolConstant){
204 bool take = ((BoolConstant) expr).Value;
207 TrueStatement.Emit (ec);
208 else if (FalseStatement != null)
209 FalseStatement.Emit (ec);
214 expr.EmitBranchable (ec, false_target, false);
216 TrueStatement.Emit (ec);
218 if (FalseStatement != null){
219 bool branch_emitted = false;
221 end = ig.DefineLabel ();
223 ig.Emit (OpCodes.Br, end);
224 branch_emitted = true;
227 ig.MarkLabel (false_target);
228 FalseStatement.Emit (ec);
233 ig.MarkLabel (false_target);
238 public class Do : Statement {
239 public Expression expr;
240 public readonly Statement EmbeddedStatement;
243 public Do (Statement statement, Expression boolExpr, Location l)
246 EmbeddedStatement = statement;
250 public override bool Resolve (EmitContext ec)
254 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
256 if (!EmbeddedStatement.Resolve (ec))
259 expr = Expression.ResolveBoolean (ec, expr, loc);
262 else if (expr is BoolConstant){
263 bool res = ((BoolConstant) expr).Value;
269 ec.CurrentBranching.Infinite = infinite;
270 ec.EndFlowBranching ();
275 protected override void DoEmit (EmitContext ec)
277 ILGenerator ig = ec.ig;
278 Label loop = ig.DefineLabel ();
279 Label old_begin = ec.LoopBegin;
280 Label old_end = ec.LoopEnd;
282 ec.LoopBegin = ig.DefineLabel ();
283 ec.LoopEnd = ig.DefineLabel ();
286 EmbeddedStatement.Emit (ec);
287 ig.MarkLabel (ec.LoopBegin);
290 // Dead code elimination
292 if (expr is BoolConstant){
293 bool res = ((BoolConstant) expr).Value;
296 ec.ig.Emit (OpCodes.Br, loop);
298 expr.EmitBranchable (ec, loop, true);
300 ig.MarkLabel (ec.LoopEnd);
302 ec.LoopBegin = old_begin;
303 ec.LoopEnd = old_end;
307 public class While : Statement {
308 public Expression expr;
309 public readonly Statement Statement;
310 bool infinite, empty;
312 public While (Expression boolExpr, Statement statement, Location l)
314 this.expr = boolExpr;
315 Statement = statement;
319 public override bool Resolve (EmitContext ec)
323 expr = Expression.ResolveBoolean (ec, expr, loc);
328 // Inform whether we are infinite or not
330 if (expr is BoolConstant){
331 BoolConstant bc = (BoolConstant) expr;
333 if (bc.Value == false){
334 if (!Statement.ResolveUnreachable (ec, true))
342 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
344 ec.CurrentBranching.CreateSibling ();
346 if (!Statement.Resolve (ec))
349 ec.CurrentBranching.Infinite = infinite;
350 ec.EndFlowBranching ();
355 protected override void DoEmit (EmitContext ec)
360 ILGenerator ig = ec.ig;
361 Label old_begin = ec.LoopBegin;
362 Label old_end = ec.LoopEnd;
364 ec.LoopBegin = ig.DefineLabel ();
365 ec.LoopEnd = ig.DefineLabel ();
368 // Inform whether we are infinite or not
370 if (expr is BoolConstant){
371 ig.MarkLabel (ec.LoopBegin);
373 ig.Emit (OpCodes.Br, ec.LoopBegin);
376 // Inform that we are infinite (ie, `we return'), only
377 // if we do not `break' inside the code.
379 ig.MarkLabel (ec.LoopEnd);
381 Label while_loop = ig.DefineLabel ();
383 ig.Emit (OpCodes.Br, ec.LoopBegin);
384 ig.MarkLabel (while_loop);
388 ig.MarkLabel (ec.LoopBegin);
390 expr.EmitBranchable (ec, while_loop, true);
392 ig.MarkLabel (ec.LoopEnd);
395 ec.LoopBegin = old_begin;
396 ec.LoopEnd = old_end;
400 public class For : Statement {
402 readonly Statement InitStatement;
403 readonly Statement Increment;
404 public readonly Statement Statement;
405 bool infinite, empty;
407 public For (Statement initStatement,
413 InitStatement = initStatement;
415 Increment = increment;
416 Statement = statement;
420 public override bool Resolve (EmitContext ec)
424 if (InitStatement != null){
425 if (!InitStatement.Resolve (ec))
430 Test = Expression.ResolveBoolean (ec, Test, loc);
433 else if (Test is BoolConstant){
434 BoolConstant bc = (BoolConstant) Test;
436 if (bc.Value == false){
437 if (!Statement.ResolveUnreachable (ec, true))
439 if ((Increment != null) &&
440 !Increment.ResolveUnreachable (ec, false))
450 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
452 ec.CurrentBranching.CreateSibling ();
454 if (!Statement.Resolve (ec))
457 if (Increment != null){
458 if (!Increment.Resolve (ec))
462 ec.CurrentBranching.Infinite = infinite;
463 ec.EndFlowBranching ();
468 protected override void DoEmit (EmitContext ec)
473 ILGenerator ig = ec.ig;
474 Label old_begin = ec.LoopBegin;
475 Label old_end = ec.LoopEnd;
476 Label loop = ig.DefineLabel ();
477 Label test = ig.DefineLabel ();
479 if (InitStatement != null && InitStatement != EmptyStatement.Value)
480 InitStatement.Emit (ec);
482 ec.LoopBegin = ig.DefineLabel ();
483 ec.LoopEnd = ig.DefineLabel ();
485 ig.Emit (OpCodes.Br, test);
489 ig.MarkLabel (ec.LoopBegin);
490 if (Increment != EmptyStatement.Value)
495 // If test is null, there is no test, and we are just
500 // The Resolve code already catches the case for
501 // Test == BoolConstant (false) so we know that
504 if (Test is BoolConstant)
505 ig.Emit (OpCodes.Br, loop);
507 Test.EmitBranchable (ec, loop, true);
510 ig.Emit (OpCodes.Br, loop);
511 ig.MarkLabel (ec.LoopEnd);
513 ec.LoopBegin = old_begin;
514 ec.LoopEnd = old_end;
518 public class StatementExpression : Statement {
519 ExpressionStatement expr;
521 public StatementExpression (ExpressionStatement expr)
527 public override bool Resolve (EmitContext ec)
530 expr = expr.ResolveStatement (ec);
534 protected override void DoEmit (EmitContext ec)
536 expr.EmitStatement (ec);
539 public override string ToString ()
541 return "StatementExpression (" + expr + ")";
546 /// Implements the return statement
548 public class Return : Statement {
549 public Expression Expr;
551 public Return (Expression expr, Location l)
559 public override bool Resolve (EmitContext ec)
561 AnonymousContainer am = ec.CurrentAnonymousMethod;
562 if ((am != null) && am.IsIterator && ec.InIterator) {
563 Report.Error (1622, loc, "Cannot return a value from iterators. Use the yield return " +
564 "statement to return a value, or yield break to end the iteration");
568 if (ec.ReturnType == null){
570 if (ec.CurrentAnonymousMethod != null){
571 Report.Error (1662, loc,
572 "Cannot convert anonymous method block to delegate type `{0}' because some of the return types in the block are not implicitly convertible to the delegate return type",
573 ec.CurrentAnonymousMethod.GetSignatureForError ());
575 Error (127, "A return keyword must not be followed by any expression when method returns void");
580 Error (126, "An object of a type convertible to `{0}' is required " +
581 "for the return statement",
582 TypeManager.CSharpName (ec.ReturnType));
586 Expr = Expr.Resolve (ec);
590 if (Expr.Type != ec.ReturnType) {
591 Expr = Convert.ImplicitConversionRequired (
592 ec, Expr, ec.ReturnType, loc);
598 FlowBranching.UsageVector vector = ec.CurrentBranching.CurrentUsageVector;
600 if (ec.CurrentBranching.InTryOrCatch (true)) {
601 ec.CurrentBranching.AddFinallyVector (vector);
603 } else if (ec.InFinally) {
604 Error (157, "Control cannot leave the body of a finally clause");
607 vector.CheckOutParameters (ec.CurrentBranching);
610 ec.NeedReturnLabel ();
612 ec.CurrentBranching.CurrentUsageVector.Return ();
616 protected override void DoEmit (EmitContext ec)
622 ec.ig.Emit (OpCodes.Stloc, ec.TemporaryReturn ());
626 ec.ig.Emit (OpCodes.Leave, ec.ReturnLabel);
628 ec.ig.Emit (OpCodes.Ret);
632 public class Goto : Statement {
634 LabeledStatement label;
636 public override bool Resolve (EmitContext ec)
638 label = ec.CurrentBranching.LookupLabel (target, loc);
642 // If this is a forward goto.
643 if (!label.IsDefined)
644 label.AddUsageVector (ec.CurrentBranching.CurrentUsageVector);
646 ec.CurrentBranching.CurrentUsageVector.Goto ();
647 label.AddReference ();
652 public Goto (string label, Location l)
658 public string Target {
664 protected override void DoEmit (EmitContext ec)
666 Label l = label.LabelTarget (ec);
667 ec.ig.Emit (OpCodes.Br, l);
671 public class LabeledStatement : Statement {
677 FlowBranching.UsageVector vectors;
679 public LabeledStatement (string label_name, Location l)
684 public Label LabelTarget (EmitContext ec)
689 label = ec.ig.DefineLabel ();
695 public bool IsDefined {
701 public bool HasBeenReferenced {
707 public void AddUsageVector (FlowBranching.UsageVector vector)
709 vector = vector.Clone ();
710 vector.Next = vectors;
714 public override bool Resolve (EmitContext ec)
716 ec.CurrentBranching.Label (vectors);
721 protected override void DoEmit (EmitContext ec)
723 if (ig != null && ig != ec.ig) {
724 // TODO: location is wrong
725 Report.Error (1632, loc, "Control cannot leave the body of an anonymous method");
729 ec.ig.MarkLabel (label);
732 public void AddReference ()
740 /// `goto default' statement
742 public class GotoDefault : Statement {
744 public GotoDefault (Location l)
749 public override bool Resolve (EmitContext ec)
751 ec.CurrentBranching.CurrentUsageVector.Goto ();
755 protected override void DoEmit (EmitContext ec)
757 if (ec.Switch == null){
758 Report.Error (153, loc, "A goto case is only valid inside a switch statement");
762 if (!ec.Switch.GotDefault){
763 Report.Error (159, loc, "No such label `default:' within the scope of the goto statement");
766 ec.ig.Emit (OpCodes.Br, ec.Switch.DefaultTarget);
771 /// `goto case' statement
773 public class GotoCase : Statement {
777 public GotoCase (Expression e, Location l)
783 public override bool Resolve (EmitContext ec)
785 if (ec.Switch == null){
786 Report.Error (153, loc, "A goto case is only valid inside a switch statement");
790 expr = expr.Resolve (ec);
794 Constant c = expr as Constant;
796 Error (150, "A constant value is expected");
800 c = c.ToType (ec.Switch.SwitchType, loc);
804 object val = c.GetValue ();
806 val = SwitchLabel.NullStringCase;
808 sl = (SwitchLabel) ec.Switch.Elements [val];
811 Report.Error (159, loc, "No such label `case {0}:' within the scope of the goto statement", c.GetValue () == null ? "null" : val);
815 ec.CurrentBranching.CurrentUsageVector.Goto ();
819 protected override void DoEmit (EmitContext ec)
821 ec.ig.Emit (OpCodes.Br, sl.GetILLabelCode (ec));
825 public class Throw : Statement {
828 public Throw (Expression expr, Location l)
834 public override bool Resolve (EmitContext ec)
836 ec.CurrentBranching.CurrentUsageVector.Throw ();
839 expr = expr.Resolve (ec);
843 ExprClass eclass = expr.eclass;
845 if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
846 eclass == ExprClass.Value || eclass == ExprClass.IndexerAccess)) {
847 expr.Error_UnexpectedKind (ec, "value, variable, property or indexer access ", loc);
853 if ((t != TypeManager.exception_type) &&
854 !t.IsSubclassOf (TypeManager.exception_type) &&
855 !(expr is NullLiteral)) {
857 "The type caught or thrown must be derived " +
858 "from System.Exception");
865 Error (156, "A throw statement with no arguments is not allowed outside of a catch clause");
870 Error (724, "A throw statement with no arguments is not allowed inside of a finally clause nested inside of the innermost catch clause");
876 protected override void DoEmit (EmitContext ec)
879 ec.ig.Emit (OpCodes.Rethrow);
883 ec.ig.Emit (OpCodes.Throw);
888 public class Break : Statement {
890 public Break (Location l)
897 public override bool Resolve (EmitContext ec)
899 if (!ec.CurrentBranching.InLoop () && !ec.CurrentBranching.InSwitch ()){
900 Error (139, "No enclosing loop out of which to break or continue");
902 } else if (ec.InFinally && ec.CurrentBranching.BreakCrossesTryCatchBoundary()) {
903 Error (157, "Control cannot leave the body of a finally clause");
905 } else if (ec.CurrentBranching.InTryOrCatch (false))
906 ec.CurrentBranching.AddFinallyVector (
907 ec.CurrentBranching.CurrentUsageVector);
908 else if (ec.CurrentBranching.InLoop () || ec.CurrentBranching.InSwitch ())
909 ec.CurrentBranching.AddBreakVector (
910 ec.CurrentBranching.CurrentUsageVector);
912 crossing_exc = ec.CurrentBranching.BreakCrossesTryCatchBoundary ();
915 ec.NeedReturnLabel ();
917 ec.CurrentBranching.CurrentUsageVector.Break ();
921 protected override void DoEmit (EmitContext ec)
923 ILGenerator ig = ec.ig;
926 ig.Emit (OpCodes.Leave, ec.LoopEnd);
928 ig.Emit (OpCodes.Br, ec.LoopEnd);
933 public class Continue : Statement {
935 public Continue (Location l)
942 public override bool Resolve (EmitContext ec)
944 if (!ec.CurrentBranching.InLoop ()){
945 Error (139, "No enclosing loop out of which to break or continue");
947 } else if (ec.InFinally) {
948 Error (157, "Control cannot leave the body of a finally clause");
950 } else if (ec.CurrentBranching.InTryOrCatch (false))
951 ec.CurrentBranching.AddFinallyVector (ec.CurrentBranching.CurrentUsageVector);
953 crossing_exc = ec.CurrentBranching.BreakCrossesTryCatchBoundary ();
955 ec.CurrentBranching.CurrentUsageVector.Goto ();
959 protected override void DoEmit (EmitContext ec)
961 Label begin = ec.LoopBegin;
964 ec.ig.Emit (OpCodes.Leave, begin);
966 ec.ig.Emit (OpCodes.Br, begin);
971 // The information about a user-perceived local variable
973 public class LocalInfo {
974 public Expression Type;
977 // Most of the time a variable will be stored in a LocalBuilder
979 // But sometimes, it will be stored in a field (variables that have been
980 // hoisted by iterators or by anonymous methods). The context of the field will
981 // be stored in the EmitContext
984 public LocalBuilder LocalBuilder;
985 public FieldBuilder FieldBuilder;
987 public Type VariableType;
988 public readonly string Name;
989 public readonly Location Location;
990 public readonly Block Block;
992 public VariableInfo VariableInfo;
1001 CompilerGenerated = 64
1004 public enum ReadOnlyContext: byte {
1011 ReadOnlyContext ro_context;
1013 public LocalInfo (Expression type, string name, Block block, Location l)
1021 public LocalInfo (TypeContainer tc, Block block, Location l)
1023 VariableType = tc.TypeBuilder;
1028 public bool IsThisAssigned (EmitContext ec, Location loc)
1030 if (VariableInfo == null)
1031 throw new Exception ();
1033 if (!ec.DoFlowAnalysis || ec.CurrentBranching.IsAssigned (VariableInfo))
1036 return VariableInfo.TypeInfo.IsFullyInitialized (ec.CurrentBranching, VariableInfo, loc);
1039 public bool IsAssigned (EmitContext ec)
1041 if (VariableInfo == null)
1042 throw new Exception ();
1044 return !ec.DoFlowAnalysis || ec.CurrentBranching.IsAssigned (VariableInfo);
1047 public bool Resolve (EmitContext ec)
1049 if (VariableType == null) {
1050 TypeExpr texpr = Type.ResolveAsTypeTerminal (ec, false);
1054 VariableType = texpr.ResolveType (ec);
1057 if (VariableType == TypeManager.void_type) {
1058 Report.Error (1547, Location,
1059 "Keyword 'void' cannot be used in this context");
1063 if (VariableType.IsAbstract && VariableType.IsSealed) {
1064 Report.Error (723, Location, "Cannot declare variable of static type `{0}'", TypeManager.CSharpName (VariableType));
1068 if (VariableType.IsPointer && !ec.InUnsafe)
1069 Expression.UnsafeError (Location);
1074 public bool IsCaptured {
1076 return (flags & Flags.Captured) != 0;
1080 flags |= Flags.Captured;
1084 public bool AddressTaken {
1086 return (flags & Flags.AddressTaken) != 0;
1090 flags |= Flags.AddressTaken;
1094 public bool CompilerGenerated {
1096 return (flags & Flags.CompilerGenerated) != 0;
1100 flags |= Flags.CompilerGenerated;
1104 public override string ToString ()
1106 return String.Format ("LocalInfo ({0},{1},{2},{3})",
1107 Name, Type, VariableInfo, Location);
1112 return (flags & Flags.Used) != 0;
1115 flags = value ? (flags | Flags.Used) : (unchecked (flags & ~Flags.Used));
1119 public bool ReadOnly {
1121 return (flags & Flags.ReadOnly) != 0;
1125 public void SetReadOnlyContext (ReadOnlyContext context)
1127 flags |= Flags.ReadOnly;
1128 ro_context = context;
1131 public string GetReadOnlyContext ()
1134 throw new InternalErrorException ("Variable is not readonly");
1136 switch (ro_context) {
1137 case ReadOnlyContext.Fixed:
1138 return "fixed variable";
1139 case ReadOnlyContext.Foreach:
1140 return "foreach iteration variable";
1141 case ReadOnlyContext.Using:
1142 return "using variable";
1144 throw new NotImplementedException ();
1148 // Whether the variable is pinned, if Pinned the variable has been
1149 // allocated in a pinned slot with DeclareLocal.
1151 public bool Pinned {
1153 return (flags & Flags.Pinned) != 0;
1156 flags = value ? (flags | Flags.Pinned) : (flags & ~Flags.Pinned);
1160 public bool IsThis {
1162 return (flags & Flags.IsThis) != 0;
1165 flags = value ? (flags | Flags.IsThis) : (flags & ~Flags.IsThis);
1171 /// Block represents a C# block.
1175 /// This class is used in a number of places: either to represent
1176 /// explicit blocks that the programmer places or implicit blocks.
1178 /// Implicit blocks are used as labels or to introduce variable
1181 /// Top-level blocks derive from Block, and they are called ToplevelBlock
1182 /// they contain extra information that is not necessary on normal blocks.
1184 public class Block : Statement {
1185 public Block Parent;
1186 public readonly Location StartLocation;
1187 public Location EndLocation = Location.Null;
1189 public readonly ToplevelBlock Toplevel;
1192 public enum Flags : ushort {
1196 VariablesInitialized = 8,
1201 HasVarargs = 256 // Used in ToplevelBlock
1203 protected Flags flags;
1205 public bool Implicit {
1206 get { return (flags & Flags.Implicit) != 0; }
1209 public bool Unchecked {
1210 get { return (flags & Flags.Unchecked) != 0; }
1211 set { flags |= Flags.Unchecked; }
1214 public bool Unsafe {
1215 get { return (flags & Flags.Unsafe) != 0; }
1216 set { flags |= Flags.Unsafe; }
1220 // The statements in this block
1222 ArrayList statements;
1226 // An array of Blocks. We keep track of children just
1227 // to generate the local variable declarations.
1229 // Statements and child statements are handled through the
1235 // Labels. (label, block) pairs.
1240 // Keeps track of (name, type) pairs
1242 Hashtable variables;
1245 // Keeps track of constants
1246 Hashtable constants;
1249 // Temporary variables.
1251 ArrayList temporary_variables;
1254 // If this is a switch section, the enclosing switch block.
1258 protected static int id;
1262 public Block (Block parent)
1263 : this (parent, (Flags) 0, Location.Null, Location.Null)
1266 public Block (Block parent, Flags flags)
1267 : this (parent, flags, Location.Null, Location.Null)
1270 public Block (Block parent, Location start, Location end)
1271 : this (parent, (Flags) 0, start, end)
1274 public Block (Block parent, Flags flags, Location start, Location end)
1277 parent.AddChild (this);
1279 this.Parent = parent;
1281 this.StartLocation = start;
1282 this.EndLocation = end;
1285 statements = new ArrayList ();
1287 if ((flags & Flags.IsToplevel) != 0)
1288 Toplevel = (ToplevelBlock) this;
1290 Toplevel = parent.Toplevel;
1292 if (parent != null && Implicit) {
1293 if (parent.known_variables == null)
1294 parent.known_variables = new Hashtable ();
1295 // share with parent
1296 known_variables = parent.known_variables;
1301 public Block CreateSwitchBlock (Location start)
1303 Block new_block = new Block (this, start, start);
1304 new_block.switch_block = this;
1309 get { return this_id; }
1312 protected Hashtable Variables {
1314 if (variables == null)
1315 variables = new Hashtable ();
1320 void AddChild (Block b)
1322 if (children == null)
1323 children = new ArrayList ();
1328 public void SetEndLocation (Location loc)
1334 /// Adds a label to the current block.
1338 /// false if the name already exists in this block. true
1342 public bool AddLabel (string name, LabeledStatement target, Location loc)
1344 if (switch_block != null)
1345 return switch_block.AddLabel (name, target, loc);
1348 while (cur != null) {
1349 if (cur.DoLookupLabel (name) != null) {
1351 140, loc, "The label `{0}' is a duplicate",
1362 while (cur != null) {
1363 if (cur.DoLookupLabel (name) != null) {
1366 "The label `{0}' shadows another label " +
1367 "by the same name in a contained scope.",
1372 if (children != null) {
1373 foreach (Block b in children) {
1374 LabeledStatement s = b.DoLookupLabel (name);
1380 "The label `{0}' shadows another " +
1381 "label by the same name in a " +
1393 labels = new Hashtable ();
1395 labels.Add (name, target);
1399 public LabeledStatement LookupLabel (string name)
1401 LabeledStatement s = DoLookupLabel (name);
1405 if (children == null)
1408 foreach (Block child in children) {
1409 if (!child.Implicit)
1412 s = child.LookupLabel (name);
1420 LabeledStatement DoLookupLabel (string name)
1422 if (switch_block != null)
1423 return switch_block.LookupLabel (name);
1426 if (labels.Contains (name))
1427 return ((LabeledStatement) labels [name]);
1432 Hashtable known_variables;
1435 // Marks a variable with name @name as being used in this or a child block.
1436 // If a variable name has been used in a child block, it's illegal to
1437 // declare a variable with the same name in the current block.
1439 void AddKnownVariable (string name, LocalInfo info)
1441 if (known_variables == null)
1442 known_variables = new Hashtable ();
1444 known_variables [name] = info;
1447 LocalInfo GetKnownVariableInfo (string name)
1449 if (known_variables == null)
1451 return (LocalInfo) known_variables [name];
1454 public bool CheckInvariantMeaningInBlock (string name, Expression e, Location loc)
1457 LocalInfo kvi = b.GetKnownVariableInfo (name);
1458 while (kvi == null) {
1464 kvi = b.GetKnownVariableInfo (name);
1470 // Is kvi.Block nested inside 'b'
1471 if (b.known_variables != kvi.Block.known_variables) {
1473 // If a variable by the same name it defined in a nested block of this
1474 // block, we violate the invariant meaning in a block.
1477 Report.SymbolRelatedToPreviousError (kvi.Location, name);
1478 Report.Error (135, loc, "`{0}' conflicts with a declaration in a child block", name);
1483 // It's ok if the definition is in a nested subblock of b, but not
1484 // nested inside this block -- a definition in a sibling block
1485 // should not affect us.
1491 // Block 'b' and kvi.Block are the same textual block.
1492 // However, different variables are extant.
1494 // Check if the variable is in scope in both blocks. We use
1495 // an indirect check that depends on AddVariable doing its
1496 // part in maintaining the invariant-meaning-in-block property.
1498 if (e is LocalVariableReference || (e is Constant && b.GetLocalInfo (name) != null))
1502 // Even though we detected the error when the name is used, we
1503 // treat it as if the variable declaration was in error.
1505 Report.SymbolRelatedToPreviousError (loc, name);
1506 Error_AlreadyDeclared (kvi.Location, name, "parent or current");
1510 public LocalInfo AddVariable (Expression type, string name, Location l)
1512 LocalInfo vi = GetLocalInfo (name);
1514 Report.SymbolRelatedToPreviousError (vi.Location, name);
1515 if (known_variables == vi.Block.known_variables)
1516 Report.Error (128, l,
1517 "A local variable named `{0}' is already defined in this scope", name);
1519 Error_AlreadyDeclared (l, name, "parent");
1523 vi = GetKnownVariableInfo (name);
1525 Report.SymbolRelatedToPreviousError (vi.Location, name);
1526 Error_AlreadyDeclared (l, name, "child");
1531 Parameter p = Toplevel.Parameters.GetParameterByName (name, out idx);
1533 Report.SymbolRelatedToPreviousError (p.Location, name);
1534 Error_AlreadyDeclared (l, name, "method argument");
1538 vi = new LocalInfo (type, name, this, l);
1540 Variables.Add (name, vi);
1542 for (Block b = this; b != null; b = b.Parent)
1543 b.AddKnownVariable (name, vi);
1545 if ((flags & Flags.VariablesInitialized) != 0)
1546 throw new Exception ();
1551 void Error_AlreadyDeclared (Location loc, string var, string reason)
1553 Report.Error (136, loc, "A local variable named `{0}' cannot be declared in this scope because it would give a different meaning to `{0}', " +
1554 "which is already used in a `{1}' scope", var, reason);
1557 public bool AddConstant (Expression type, string name, Expression value, Location l)
1559 if (AddVariable (type, name, l) == null)
1562 if (constants == null)
1563 constants = new Hashtable ();
1565 constants.Add (name, value);
1567 // A block is considered used if we perform an initialization in a local declaration, even if it is constant.
1572 static int next_temp_id = 0;
1574 public LocalInfo AddTemporaryVariable (TypeExpr te, Location loc)
1576 if (temporary_variables == null)
1577 temporary_variables = new ArrayList ();
1579 int id = ++next_temp_id;
1580 string name = "$s_" + id.ToString ();
1582 LocalInfo li = new LocalInfo (te, name, this, loc);
1583 li.CompilerGenerated = true;
1584 temporary_variables.Add (li);
1588 public LocalInfo GetLocalInfo (string name)
1590 for (Block b = this; b != null; b = b.Parent) {
1591 if (b.variables != null) {
1592 LocalInfo ret = b.variables [name] as LocalInfo;
1600 public Expression GetVariableType (string name)
1602 LocalInfo vi = GetLocalInfo (name);
1603 return vi == null ? null : vi.Type;
1606 public Expression GetConstantExpression (string name)
1608 for (Block b = this; b != null; b = b.Parent) {
1609 if (b.constants != null) {
1610 Expression ret = b.constants [name] as Expression;
1619 /// True if the variable named @name is a constant
1621 public bool IsConstant (string name)
1623 Expression e = GetConstantExpression (name);
1627 public void AddStatement (Statement s)
1630 flags |= Flags.BlockUsed;
1634 get { return (flags & Flags.BlockUsed) != 0; }
1639 flags |= Flags.BlockUsed;
1642 public bool HasRet {
1643 get { return (flags & Flags.HasRet) != 0; }
1646 public bool IsDestructor {
1647 get { return (flags & Flags.IsDestructor) != 0; }
1650 public void SetDestructor ()
1652 flags |= Flags.IsDestructor;
1655 VariableMap param_map, local_map;
1657 public VariableMap ParameterMap {
1659 if ((flags & Flags.VariablesInitialized) == 0)
1660 throw new Exception ("Variables have not been initialized yet");
1666 public VariableMap LocalMap {
1668 if ((flags & Flags.VariablesInitialized) == 0)
1669 throw new Exception ("Variables have not been initialized yet");
1676 /// Emits the variable declarations and labels.
1679 /// tc: is our typecontainer (to resolve type references)
1680 /// ig: is the code generator:
1682 public void ResolveMeta (ToplevelBlock toplevel, EmitContext ec, InternalParameters ip)
1684 bool old_unsafe = ec.InUnsafe;
1686 // If some parent block was unsafe, we remain unsafe even if this block
1687 // isn't explicitly marked as such.
1688 ec.InUnsafe |= Unsafe;
1691 // Compute the VariableMap's.
1693 // Unfortunately, we don't know the type when adding variables with
1694 // AddVariable(), so we need to compute this info here.
1698 if (variables != null) {
1699 foreach (LocalInfo li in variables.Values)
1702 locals = new LocalInfo [variables.Count];
1703 variables.Values.CopyTo (locals, 0);
1705 locals = new LocalInfo [0];
1708 local_map = new VariableMap (Parent.LocalMap, locals);
1710 local_map = new VariableMap (locals);
1712 param_map = new VariableMap (ip);
1713 flags |= Flags.VariablesInitialized;
1715 bool old_check_state = ec.ConstantCheckState;
1716 ec.ConstantCheckState = (flags & Flags.Unchecked) == 0;
1719 // Process this block variables
1721 if (variables != null){
1722 foreach (DictionaryEntry de in variables){
1723 string name = (string) de.Key;
1724 LocalInfo vi = (LocalInfo) de.Value;
1726 if (vi.VariableType == null)
1729 Type variable_type = vi.VariableType;
1731 if (variable_type.IsPointer){
1733 // Am not really convinced that this test is required (Microsoft does it)
1734 // but the fact is that you would not be able to use the pointer variable
1737 if (!TypeManager.VerifyUnManaged (TypeManager.GetElementType (variable_type),
1742 if (constants == null)
1745 Expression cv = (Expression) constants [name];
1749 // Don't let 'const int Foo = Foo;' succeed.
1750 // Removing the name from 'constants' ensures that we get a LocalVariableReference below,
1751 // which in turn causes the 'must be constant' error to be triggered.
1752 constants.Remove (name);
1754 ec.CurrentBlock = this;
1755 Expression e = cv.Resolve (ec);
1759 Constant ce = e as Constant;
1761 Const.Error_ExpressionMustBeConstant (vi.Location, name);
1765 e = ce.ToType (variable_type, vi.Location);
1769 constants.Add (name, e);
1772 ec.ConstantCheckState = old_check_state;
1775 // Now, handle the children
1777 if (children != null){
1778 foreach (Block b in children)
1779 b.ResolveMeta (toplevel, ec, ip);
1781 ec.InUnsafe = old_unsafe;
1785 // Emits the local variable declarations for a block
1787 public void EmitMeta (EmitContext ec)
1789 ILGenerator ig = ec.ig;
1791 if (variables != null){
1792 bool have_captured_vars = ec.HaveCapturedVariables ();
1794 foreach (DictionaryEntry de in variables){
1795 LocalInfo vi = (LocalInfo) de.Value;
1797 if (have_captured_vars && ec.IsCaptured (vi))
1802 // This is needed to compile on both .NET 1.x and .NET 2.x
1803 // the later introduced `DeclareLocal (Type t, bool pinned)'
1805 vi.LocalBuilder = TypeManager.DeclareLocalPinned (ig, vi.VariableType);
1806 else if (!vi.IsThis)
1807 vi.LocalBuilder = ig.DeclareLocal (vi.VariableType);
1811 if (temporary_variables != null) {
1812 AnonymousContainer am = ec.CurrentAnonymousMethod;
1813 TypeBuilder scope = null;
1814 if ((am != null) && am.IsIterator) {
1815 scope = am.Scope.ScopeTypeBuilder;
1817 throw new InternalErrorException ();
1819 foreach (LocalInfo vi in temporary_variables) {
1820 if (scope != null) {
1821 if (vi.FieldBuilder == null)
1822 vi.FieldBuilder = scope.DefineField (
1823 vi.Name, vi.VariableType, FieldAttributes.Assembly);
1825 vi.LocalBuilder = ig.DeclareLocal (vi.VariableType);
1829 if (children != null){
1830 foreach (Block b in children)
1835 void UsageWarning (FlowBranching.UsageVector vector)
1839 if ((variables != null) && (RootContext.WarningLevel >= 3)) {
1840 foreach (DictionaryEntry de in variables){
1841 LocalInfo vi = (LocalInfo) de.Value;
1846 name = (string) de.Key;
1848 if (vector.IsAssigned (vi.VariableInfo)){
1849 Report.Warning (219, vi.Location, "The variable `{0}' is assigned but its value is never used", name);
1851 Report.Warning (168, vi.Location, "The variable `{0}' is declared but never used", name);
1857 bool unreachable_shown;
1860 private void CheckPossibleMistakenEmptyStatement (Statement s)
1864 // Some statements are wrapped by a Block. Since
1865 // others' internal could be changed, here I treat
1866 // them as possibly wrapped by Block equally.
1867 Block b = s as Block;
1868 if (b != null && b.statements.Count == 1)
1869 s = (Statement) b.statements [0];
1872 body = ((Lock) s).Statement;
1874 body = ((For) s).Statement;
1875 else if (s is Foreach)
1876 body = ((Foreach) s).Statement;
1877 else if (s is While)
1878 body = ((While) s).Statement;
1879 else if (s is Using)
1880 body = ((Using) s).Statement;
1881 else if (s is Fixed)
1882 body = ((Fixed) s).Statement;
1886 if (body == null || body is EmptyStatement)
1887 Report.Warning (642, 3, s.loc, "Possible mistaken empty statement");
1890 public override bool Resolve (EmitContext ec)
1892 Block prev_block = ec.CurrentBlock;
1895 int errors = Report.Errors;
1897 ec.CurrentBlock = this;
1898 ec.StartFlowBranching (this);
1900 Report.Debug (4, "RESOLVE BLOCK", StartLocation, ec.CurrentBranching);
1902 int statement_count = statements.Count;
1903 for (int ix = 0; ix < statement_count; ix++){
1904 Statement s = (Statement) statements [ix];
1905 // Check possible empty statement (CS0642)
1906 if (RootContext.WarningLevel >= 3 &&
1907 ix + 1 < statement_count &&
1908 statements [ix + 1] is Block)
1909 CheckPossibleMistakenEmptyStatement (s);
1912 // Warn if we detect unreachable code.
1916 ((Block) s).unreachable = true;
1918 if (!unreachable_shown && (RootContext.WarningLevel >= 2)) {
1920 162, s.loc, "Unreachable code detected");
1921 unreachable_shown = true;
1926 // Note that we're not using ResolveUnreachable() for unreachable
1927 // statements here. ResolveUnreachable() creates a temporary
1928 // flow branching and kills it afterwards. This leads to problems
1929 // if you have two unreachable statements where the first one
1930 // assigns a variable and the second one tries to access it.
1933 if (!s.Resolve (ec)) {
1935 statements [ix] = EmptyStatement.Value;
1939 if (unreachable && !(s is LabeledStatement) && !(s is Block))
1940 statements [ix] = EmptyStatement.Value;
1942 num_statements = ix + 1;
1943 if (s is LabeledStatement)
1944 unreachable = false;
1946 unreachable = ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable;
1949 Report.Debug (4, "RESOLVE BLOCK DONE", StartLocation,
1950 ec.CurrentBranching, statement_count, num_statements);
1952 FlowBranching.UsageVector vector = ec.DoEndFlowBranching ();
1954 ec.CurrentBlock = prev_block;
1956 // If we're a non-static `struct' constructor which doesn't have an
1957 // initializer, then we must initialize all of the struct's fields.
1958 if ((flags & Flags.IsToplevel) != 0 &&
1959 !Toplevel.IsThisAssigned (ec) &&
1960 vector.Reachability.Throws != FlowBranching.FlowReturns.Always)
1963 if ((labels != null) && (RootContext.WarningLevel >= 2)) {
1964 foreach (LabeledStatement label in labels.Values)
1965 if (!label.HasBeenReferenced)
1966 Report.Warning (164, label.loc,
1967 "This label has not been referenced");
1970 Report.Debug (4, "RESOLVE BLOCK DONE #2", StartLocation, vector);
1972 if ((vector.Reachability.Returns == FlowBranching.FlowReturns.Always) ||
1973 (vector.Reachability.Throws == FlowBranching.FlowReturns.Always) ||
1974 (vector.Reachability.Reachable == FlowBranching.FlowReturns.Never))
1975 flags |= Flags.HasRet;
1977 if (ok && (errors == Report.Errors)) {
1978 if (RootContext.WarningLevel >= 3)
1979 UsageWarning (vector);
1985 public override bool ResolveUnreachable (EmitContext ec, bool warn)
1987 unreachable_shown = true;
1990 if (warn && (RootContext.WarningLevel >= 2))
1991 Report.Warning (162, loc, "Unreachable code detected");
1993 ec.StartFlowBranching (FlowBranching.BranchingType.Block, loc);
1994 bool ok = Resolve (ec);
1995 ec.KillFlowBranching ();
2000 protected override void DoEmit (EmitContext ec)
2002 for (int ix = 0; ix < num_statements; ix++){
2003 Statement s = (Statement) statements [ix];
2005 // Check whether we are the last statement in a
2008 if (((Parent == null) || Implicit) && (ix+1 == num_statements) && !(s is Block))
2009 ec.IsLastStatement = true;
2011 ec.IsLastStatement = false;
2017 public override void Emit (EmitContext ec)
2019 Block prev_block = ec.CurrentBlock;
2021 ec.CurrentBlock = this;
2023 bool emit_debug_info = (CodeGen.SymbolWriter != null);
2024 bool is_lexical_block = !Implicit && (Parent != null);
2026 if (emit_debug_info) {
2027 if (is_lexical_block)
2030 if (variables != null) {
2031 foreach (DictionaryEntry de in variables) {
2032 string name = (string) de.Key;
2033 LocalInfo vi = (LocalInfo) de.Value;
2035 if (vi.LocalBuilder == null)
2038 ec.DefineLocalVariable (name, vi.LocalBuilder);
2043 ec.Mark (StartLocation, true);
2045 ec.Mark (EndLocation, true);
2047 if (emit_debug_info && is_lexical_block)
2050 ec.CurrentBlock = prev_block;
2054 // Returns true if we ar ea child of `b'.
2056 public bool IsChildOf (Block b)
2058 Block current = this;
2061 if (current.Parent == b)
2063 current = current.Parent;
2064 } while (current != null);
2068 public override string ToString ()
2070 return String.Format ("{0} ({1}:{2})", GetType (),ID, StartLocation);
2075 // A toplevel block contains extra information, the split is done
2076 // only to separate information that would otherwise bloat the more
2077 // lightweight Block.
2079 // In particular, this was introduced when the support for Anonymous
2080 // Methods was implemented.
2082 public class ToplevelBlock : Block {
2084 // Pointer to the host of this anonymous method, or null
2085 // if we are the topmost block
2087 ToplevelBlock container;
2088 CaptureContext capture_context;
2089 FlowBranching top_level_branching;
2091 Hashtable capture_contexts;
2094 public bool HasVarargs {
2095 get { return (flags & Flags.HasVarargs) != 0; }
2096 set { flags |= Flags.HasVarargs; }
2100 // The parameters for the block.
2102 public readonly Parameters Parameters;
2104 public void RegisterCaptureContext (CaptureContext cc)
2106 if (capture_contexts == null)
2107 capture_contexts = new Hashtable ();
2108 capture_contexts [cc] = cc;
2111 public void CompleteContexts ()
2113 if (capture_contexts == null)
2116 foreach (CaptureContext cc in capture_contexts.Keys){
2121 public CaptureContext ToplevelBlockCaptureContext {
2122 get { return capture_context; }
2125 public ToplevelBlock Container {
2126 get { return container; }
2129 protected void AddChild (ToplevelBlock block)
2131 if (children == null)
2132 children = new ArrayList ();
2134 children.Add (block);
2138 // Parent is only used by anonymous blocks to link back to their
2141 public ToplevelBlock (ToplevelBlock container, Parameters parameters, Location start) :
2142 this (container, (Flags) 0, parameters, start)
2146 public ToplevelBlock (Parameters parameters, Location start) :
2147 this (null, (Flags) 0, parameters, start)
2151 public ToplevelBlock (Flags flags, Parameters parameters, Location start) :
2152 this (null, flags, parameters, start)
2156 public ToplevelBlock (ToplevelBlock container, Flags flags, Parameters parameters, Location start) :
2157 base (null, flags | Flags.IsToplevel, start, Location.Null)
2159 Parameters = parameters == null ? Parameters.EmptyReadOnlyParameters : parameters;
2160 this.container = container;
2162 if (container != null)
2163 container.AddChild (this);
2166 public ToplevelBlock (Location loc) : this (null, (Flags) 0, null, loc)
2170 public void SetHaveAnonymousMethods (Location loc, AnonymousContainer host)
2172 if (capture_context == null)
2173 capture_context = new CaptureContext (this, loc, host);
2176 public CaptureContext CaptureContext {
2177 get { return capture_context; }
2180 public FlowBranching TopLevelBranching {
2181 get { return top_level_branching; }
2185 // This is used if anonymous methods are used inside an iterator
2186 // (see 2test-22.cs for an example).
2188 // The AnonymousMethod is created while parsing - at a time when we don't
2189 // know yet that we're inside an iterator, so it's `Container' is initially
2190 // null. Later on, when resolving the iterator, we need to move the
2191 // anonymous method into that iterator.
2193 public void ReParent (ToplevelBlock new_parent, AnonymousContainer new_host)
2195 foreach (ToplevelBlock block in children) {
2196 if (block.CaptureContext == null)
2199 block.container = new_parent;
2200 block.CaptureContext.ReParent (new_parent, new_host);
2205 // Returns a `ParameterReference' for the given name, or null if there
2206 // is no such parameter
2208 public ParameterReference GetParameterReference (string name, Location loc)
2213 for (ToplevelBlock t = this; t != null; t = t.Container) {
2214 Parameters pars = t.Parameters;
2215 par = pars.GetParameterByName (name, out idx);
2217 return new ParameterReference (pars, this, idx, name, loc);
2223 // Whether the parameter named `name' is local to this block,
2224 // or false, if the parameter belongs to an encompassing block.
2226 public bool IsLocalParameter (string name)
2228 return Parameters.GetParameterByName (name) != null;
2232 // Whether the `name' is a parameter reference
2234 public bool IsParameterReference (string name)
2236 for (ToplevelBlock t = this; t != null; t = t.Container) {
2237 if (t.IsLocalParameter (name))
2243 LocalInfo this_variable = null;
2246 // Returns the "this" instance variable of this block.
2247 // See AddThisVariable() for more information.
2249 public LocalInfo ThisVariable {
2250 get { return this_variable; }
2255 // This is used by non-static `struct' constructors which do not have an
2256 // initializer - in this case, the constructor must initialize all of the
2257 // struct's fields. To do this, we add a "this" variable and use the flow
2258 // analysis code to ensure that it's been fully initialized before control
2259 // leaves the constructor.
2261 public LocalInfo AddThisVariable (TypeContainer tc, Location l)
2263 if (this_variable == null) {
2264 this_variable = new LocalInfo (tc, this, l);
2265 this_variable.Used = true;
2266 this_variable.IsThis = true;
2268 Variables.Add ("this", this_variable);
2271 return this_variable;
2274 public bool IsThisAssigned (EmitContext ec)
2276 return this_variable == null || this_variable.IsThisAssigned (ec, loc);
2279 public bool ResolveMeta (EmitContext ec, InternalParameters ip)
2281 int errors = Report.Errors;
2283 if (top_level_branching != null)
2286 ResolveMeta (this, ec, ip);
2288 top_level_branching = ec.StartFlowBranching (this);
2290 return Report.Errors == errors;
2294 public class SwitchLabel {
2301 Label il_label_code;
2302 bool il_label_code_set;
2304 public static readonly object NullStringCase = new object ();
2307 // if expr == null, then it is the default case.
2309 public SwitchLabel (Expression expr, Location l)
2315 public Expression Label {
2321 public object Converted {
2327 public Label GetILLabel (EmitContext ec)
2330 il_label = ec.ig.DefineLabel ();
2331 il_label_set = true;
2336 public Label GetILLabelCode (EmitContext ec)
2338 if (!il_label_code_set){
2339 il_label_code = ec.ig.DefineLabel ();
2340 il_label_code_set = true;
2342 return il_label_code;
2346 // Resolves the expression, reduces it to a literal if possible
2347 // and then converts it to the requested type.
2349 public bool ResolveAndReduce (EmitContext ec, Type required_type)
2351 Expression e = label.Resolve (ec);
2356 Constant c = e as Constant;
2358 Report.Error (150, loc, "A constant value is expected");
2362 if (required_type == TypeManager.string_type && e is NullLiteral) {
2363 converted = NullStringCase;
2367 c = c.ToType (required_type, loc);
2371 converted = c.GetValue ();
2375 public void Erorr_AlreadyOccurs ()
2378 if (converted == null)
2380 else if (converted is NullLiteral)
2383 label = converted.ToString ();
2385 Report.Error (152, loc, "The label `case {0}:' already occurs in this switch statement", label);
2389 public class SwitchSection {
2390 // An array of SwitchLabels.
2391 public readonly ArrayList Labels;
2392 public readonly Block Block;
2394 public SwitchSection (ArrayList labels, Block block)
2401 public class Switch : Statement {
2402 public readonly ArrayList Sections;
2403 public Expression Expr;
2406 /// Maps constants whose type type SwitchType to their SwitchLabels.
2408 public IDictionary Elements;
2411 /// The governing switch type
2413 public Type SwitchType;
2418 Label default_target;
2419 Expression new_expr;
2421 SwitchSection constant_section;
2422 SwitchSection default_section;
2425 // The types allowed to be implicitly cast from
2426 // on the governing type
2428 static Type [] allowed_types;
2430 public Switch (Expression e, ArrayList sects, Location l)
2437 public bool GotDefault {
2439 return default_section != null;
2443 public Label DefaultTarget {
2445 return default_target;
2450 // Determines the governing type for a switch. The returned
2451 // expression might be the expression from the switch, or an
2452 // expression that includes any potential conversions to the
2453 // integral types or to string.
2455 Expression SwitchGoverningType (EmitContext ec, Type t)
2457 if (t == TypeManager.byte_type ||
2458 t == TypeManager.sbyte_type ||
2459 t == TypeManager.ushort_type ||
2460 t == TypeManager.short_type ||
2461 t == TypeManager.uint32_type ||
2462 t == TypeManager.int32_type ||
2463 t == TypeManager.uint64_type ||
2464 t == TypeManager.int64_type ||
2465 t == TypeManager.char_type ||
2466 t == TypeManager.string_type ||
2467 t == TypeManager.bool_type ||
2468 t.IsSubclassOf (TypeManager.enum_type))
2471 if (allowed_types == null){
2472 allowed_types = new Type [] {
2473 TypeManager.sbyte_type,
2474 TypeManager.byte_type,
2475 TypeManager.short_type,
2476 TypeManager.ushort_type,
2477 TypeManager.int32_type,
2478 TypeManager.uint32_type,
2479 TypeManager.int64_type,
2480 TypeManager.uint64_type,
2481 TypeManager.char_type,
2482 TypeManager.string_type,
2483 TypeManager.bool_type
2488 // Try to find a *user* defined implicit conversion.
2490 // If there is no implicit conversion, or if there are multiple
2491 // conversions, we have to report an error
2493 Expression converted = null;
2494 foreach (Type tt in allowed_types){
2497 e = Convert.ImplicitUserConversion (ec, Expr, tt, loc);
2502 // Ignore over-worked ImplicitUserConversions that do
2503 // an implicit conversion in addition to the user conversion.
2505 if (!(e is UserCast))
2508 if (converted != null){
2509 Report.ExtraInformation (
2511 String.Format ("reason: more than one conversion to an integral type exist for type {0}",
2512 TypeManager.CSharpName (Expr.Type)));
2522 // Performs the basic sanity checks on the switch statement
2523 // (looks for duplicate keys and non-constant expressions).
2525 // It also returns a hashtable with the keys that we will later
2526 // use to compute the switch tables
2528 bool CheckSwitch (EmitContext ec)
2531 Elements = Sections.Count > 10 ?
2532 (IDictionary)new Hashtable () :
2533 (IDictionary)new ListDictionary ();
2535 foreach (SwitchSection ss in Sections){
2536 foreach (SwitchLabel sl in ss.Labels){
2537 if (sl.Label == null){
2538 if (default_section != null){
2539 sl.Erorr_AlreadyOccurs ();
2542 default_section = ss;
2546 if (!sl.ResolveAndReduce (ec, SwitchType)){
2551 object key = sl.Converted;
2553 Elements.Add (key, sl);
2555 catch (ArgumentException) {
2556 sl.Erorr_AlreadyOccurs ();
2564 void EmitObjectInteger (ILGenerator ig, object k)
2567 IntConstant.EmitInt (ig, (int) k);
2568 else if (k is Constant) {
2569 EmitObjectInteger (ig, ((Constant) k).GetValue ());
2572 IntConstant.EmitInt (ig, unchecked ((int) (uint) k));
2575 if ((long) k >= int.MinValue && (long) k <= int.MaxValue)
2577 IntConstant.EmitInt (ig, (int) (long) k);
2578 ig.Emit (OpCodes.Conv_I8);
2581 LongConstant.EmitLong (ig, (long) k);
2583 else if (k is ulong)
2585 if ((ulong) k < (1L<<32))
2587 IntConstant.EmitInt (ig, (int) (long) k);
2588 ig.Emit (OpCodes.Conv_U8);
2592 LongConstant.EmitLong (ig, unchecked ((long) (ulong) k));
2596 IntConstant.EmitInt (ig, (int) ((char) k));
2597 else if (k is sbyte)
2598 IntConstant.EmitInt (ig, (int) ((sbyte) k));
2600 IntConstant.EmitInt (ig, (int) ((byte) k));
2601 else if (k is short)
2602 IntConstant.EmitInt (ig, (int) ((short) k));
2603 else if (k is ushort)
2604 IntConstant.EmitInt (ig, (int) ((ushort) k));
2606 IntConstant.EmitInt (ig, ((bool) k) ? 1 : 0);
2608 throw new Exception ("Unhandled case");
2611 // structure used to hold blocks of keys while calculating table switch
2612 class KeyBlock : IComparable
2614 public KeyBlock (long _nFirst)
2616 nFirst = nLast = _nFirst;
2620 public ArrayList rgKeys = null;
2621 // how many items are in the bucket
2622 public int Size = 1;
2625 get { return (int) (nLast - nFirst + 1); }
2627 public static long TotalLength (KeyBlock kbFirst, KeyBlock kbLast)
2629 return kbLast.nLast - kbFirst.nFirst + 1;
2631 public int CompareTo (object obj)
2633 KeyBlock kb = (KeyBlock) obj;
2634 int nLength = Length;
2635 int nLengthOther = kb.Length;
2636 if (nLengthOther == nLength)
2637 return (int) (kb.nFirst - nFirst);
2638 return nLength - nLengthOther;
2643 /// This method emits code for a lookup-based switch statement (non-string)
2644 /// Basically it groups the cases into blocks that are at least half full,
2645 /// and then spits out individual lookup opcodes for each block.
2646 /// It emits the longest blocks first, and short blocks are just
2647 /// handled with direct compares.
2649 /// <param name="ec"></param>
2650 /// <param name="val"></param>
2651 /// <returns></returns>
2652 void TableSwitchEmit (EmitContext ec, LocalBuilder val)
2654 int cElements = Elements.Count;
2655 object [] rgKeys = new object [cElements];
2656 Elements.Keys.CopyTo (rgKeys, 0);
2657 Array.Sort (rgKeys);
2659 // initialize the block list with one element per key
2660 ArrayList rgKeyBlocks = new ArrayList ();
2661 foreach (object key in rgKeys)
2662 rgKeyBlocks.Add (new KeyBlock (System.Convert.ToInt64 (key)));
2665 // iteratively merge the blocks while they are at least half full
2666 // there's probably a really cool way to do this with a tree...
2667 while (rgKeyBlocks.Count > 1)
2669 ArrayList rgKeyBlocksNew = new ArrayList ();
2670 kbCurr = (KeyBlock) rgKeyBlocks [0];
2671 for (int ikb = 1; ikb < rgKeyBlocks.Count; ikb++)
2673 KeyBlock kb = (KeyBlock) rgKeyBlocks [ikb];
2674 if ((kbCurr.Size + kb.Size) * 2 >= KeyBlock.TotalLength (kbCurr, kb))
2677 kbCurr.nLast = kb.nLast;
2678 kbCurr.Size += kb.Size;
2682 // start a new block
2683 rgKeyBlocksNew.Add (kbCurr);
2687 rgKeyBlocksNew.Add (kbCurr);
2688 if (rgKeyBlocks.Count == rgKeyBlocksNew.Count)
2690 rgKeyBlocks = rgKeyBlocksNew;
2693 // initialize the key lists
2694 foreach (KeyBlock kb in rgKeyBlocks)
2695 kb.rgKeys = new ArrayList ();
2697 // fill the key lists
2699 if (rgKeyBlocks.Count > 0) {
2700 kbCurr = (KeyBlock) rgKeyBlocks [0];
2701 foreach (object key in rgKeys)
2703 bool fNextBlock = (key is UInt64) ? (ulong) key > (ulong) kbCurr.nLast :
2704 System.Convert.ToInt64 (key) > kbCurr.nLast;
2706 kbCurr = (KeyBlock) rgKeyBlocks [++iBlockCurr];
2707 kbCurr.rgKeys.Add (key);
2711 // sort the blocks so we can tackle the largest ones first
2712 rgKeyBlocks.Sort ();
2714 // okay now we can start...
2715 ILGenerator ig = ec.ig;
2716 Label lblEnd = ig.DefineLabel (); // at the end ;-)
2717 Label lblDefault = ig.DefineLabel ();
2719 Type typeKeys = null;
2720 if (rgKeys.Length > 0)
2721 typeKeys = rgKeys [0].GetType (); // used for conversions
2725 if (TypeManager.IsEnumType (SwitchType))
2726 compare_type = TypeManager.EnumToUnderlying (SwitchType);
2728 compare_type = SwitchType;
2730 for (int iBlock = rgKeyBlocks.Count - 1; iBlock >= 0; --iBlock)
2732 KeyBlock kb = ((KeyBlock) rgKeyBlocks [iBlock]);
2733 lblDefault = (iBlock == 0) ? DefaultTarget : ig.DefineLabel ();
2736 foreach (object key in kb.rgKeys)
2738 ig.Emit (OpCodes.Ldloc, val);
2739 EmitObjectInteger (ig, key);
2740 SwitchLabel sl = (SwitchLabel) Elements [key];
2741 ig.Emit (OpCodes.Beq, sl.GetILLabel (ec));
2746 // TODO: if all the keys in the block are the same and there are
2747 // no gaps/defaults then just use a range-check.
2748 if (compare_type == TypeManager.int64_type ||
2749 compare_type == TypeManager.uint64_type)
2751 // TODO: optimize constant/I4 cases
2753 // check block range (could be > 2^31)
2754 ig.Emit (OpCodes.Ldloc, val);
2755 EmitObjectInteger (ig, System.Convert.ChangeType (kb.nFirst, typeKeys));
2756 ig.Emit (OpCodes.Blt, lblDefault);
2757 ig.Emit (OpCodes.Ldloc, val);
2758 EmitObjectInteger (ig, System.Convert.ChangeType (kb.nLast, typeKeys));
2759 ig.Emit (OpCodes.Bgt, lblDefault);
2762 ig.Emit (OpCodes.Ldloc, val);
2765 EmitObjectInteger (ig, System.Convert.ChangeType (kb.nFirst, typeKeys));
2766 ig.Emit (OpCodes.Sub);
2768 ig.Emit (OpCodes.Conv_I4); // assumes < 2^31 labels!
2773 ig.Emit (OpCodes.Ldloc, val);
2774 int nFirst = (int) kb.nFirst;
2777 IntConstant.EmitInt (ig, nFirst);
2778 ig.Emit (OpCodes.Sub);
2780 else if (nFirst < 0)
2782 IntConstant.EmitInt (ig, -nFirst);
2783 ig.Emit (OpCodes.Add);
2787 // first, build the list of labels for the switch
2789 int cJumps = kb.Length;
2790 Label [] rgLabels = new Label [cJumps];
2791 for (int iJump = 0; iJump < cJumps; iJump++)
2793 object key = kb.rgKeys [iKey];
2794 if (System.Convert.ToInt64 (key) == kb.nFirst + iJump)
2796 SwitchLabel sl = (SwitchLabel) Elements [key];
2797 rgLabels [iJump] = sl.GetILLabel (ec);
2801 rgLabels [iJump] = lblDefault;
2803 // emit the switch opcode
2804 ig.Emit (OpCodes.Switch, rgLabels);
2807 // mark the default for this block
2809 ig.MarkLabel (lblDefault);
2812 // TODO: find the default case and emit it here,
2813 // to prevent having to do the following jump.
2814 // make sure to mark other labels in the default section
2816 // the last default just goes to the end
2817 ig.Emit (OpCodes.Br, lblDefault);
2819 // now emit the code for the sections
2820 bool fFoundDefault = false;
2821 foreach (SwitchSection ss in Sections)
2823 foreach (SwitchLabel sl in ss.Labels)
2825 ig.MarkLabel (sl.GetILLabel (ec));
2826 ig.MarkLabel (sl.GetILLabelCode (ec));
2827 if (sl.Label == null)
2829 ig.MarkLabel (lblDefault);
2830 fFoundDefault = true;
2834 //ig.Emit (OpCodes.Br, lblEnd);
2837 if (!fFoundDefault) {
2838 ig.MarkLabel (lblDefault);
2840 ig.MarkLabel (lblEnd);
2843 // This simple emit switch works, but does not take advantage of the
2845 // TODO: remove non-string logic from here
2846 // TODO: binary search strings?
2848 void SimpleSwitchEmit (EmitContext ec, LocalBuilder val)
2850 ILGenerator ig = ec.ig;
2851 Label end_of_switch = ig.DefineLabel ();
2852 Label next_test = ig.DefineLabel ();
2853 Label null_target = ig.DefineLabel ();
2854 bool first_test = true;
2855 bool pending_goto_end = false;
2856 bool null_marked = false;
2859 ig.Emit (OpCodes.Ldloc, val);
2861 if (Elements.Contains (SwitchLabel.NullStringCase)){
2862 ig.Emit (OpCodes.Brfalse, null_target);
2864 ig.Emit (OpCodes.Brfalse, default_target);
2866 ig.Emit (OpCodes.Ldloc, val);
2867 ig.Emit (OpCodes.Call, TypeManager.string_isinterneted_string);
2868 ig.Emit (OpCodes.Stloc, val);
2870 int section_count = Sections.Count;
2871 for (int section = 0; section < section_count; section++){
2872 SwitchSection ss = (SwitchSection) Sections [section];
2874 if (ss == default_section)
2877 Label sec_begin = ig.DefineLabel ();
2879 ig.Emit (OpCodes.Nop);
2881 if (pending_goto_end)
2882 ig.Emit (OpCodes.Br, end_of_switch);
2884 int label_count = ss.Labels.Count;
2886 for (int label = 0; label < label_count; label++){
2887 SwitchLabel sl = (SwitchLabel) ss.Labels [label];
2888 ig.MarkLabel (sl.GetILLabel (ec));
2891 ig.MarkLabel (next_test);
2892 next_test = ig.DefineLabel ();
2895 // If we are the default target
2897 if (sl.Label != null){
2898 object lit = sl.Converted;
2900 if (lit == SwitchLabel.NullStringCase){
2902 if (label_count == 1)
2903 ig.Emit (OpCodes.Br, next_test);
2907 ig.Emit (OpCodes.Ldloc, val);
2908 ig.Emit (OpCodes.Ldstr, (string)lit);
2909 if (label_count == 1)
2910 ig.Emit (OpCodes.Bne_Un, next_test);
2912 if (label+1 == label_count)
2913 ig.Emit (OpCodes.Bne_Un, next_test);
2915 ig.Emit (OpCodes.Beq, sec_begin);
2920 ig.MarkLabel (null_target);
2923 ig.MarkLabel (sec_begin);
2924 foreach (SwitchLabel sl in ss.Labels)
2925 ig.MarkLabel (sl.GetILLabelCode (ec));
2928 pending_goto_end = !ss.Block.HasRet;
2931 ig.MarkLabel (next_test);
2932 ig.MarkLabel (default_target);
2934 ig.MarkLabel (null_target);
2935 if (default_section != null)
2936 default_section.Block.Emit (ec);
2937 ig.MarkLabel (end_of_switch);
2940 SwitchSection FindSection (SwitchLabel label)
2942 foreach (SwitchSection ss in Sections){
2943 foreach (SwitchLabel sl in ss.Labels){
2952 public override bool Resolve (EmitContext ec)
2954 Expr = Expr.Resolve (ec);
2958 new_expr = SwitchGoverningType (ec, Expr.Type);
2959 if (new_expr == null){
2960 Report.Error (151, loc, "A value of an integral type or string expected for switch");
2965 SwitchType = new_expr.Type;
2967 if (!CheckSwitch (ec))
2970 Switch old_switch = ec.Switch;
2972 ec.Switch.SwitchType = SwitchType;
2974 Report.Debug (1, "START OF SWITCH BLOCK", loc, ec.CurrentBranching);
2975 ec.StartFlowBranching (FlowBranching.BranchingType.Switch, loc);
2977 is_constant = new_expr is Constant;
2979 object key = ((Constant) new_expr).GetValue ();
2980 SwitchLabel label = (SwitchLabel) Elements [key];
2982 constant_section = FindSection (label);
2983 if (constant_section == null)
2984 constant_section = default_section;
2988 foreach (SwitchSection ss in Sections){
2990 ec.CurrentBranching.CreateSibling (
2991 null, FlowBranching.SiblingType.SwitchSection);
2995 if (is_constant && (ss != constant_section)) {
2996 // If we're a constant switch, we're only emitting
2997 // one single section - mark all the others as
2999 ec.CurrentBranching.CurrentUsageVector.Goto ();
3000 if (!ss.Block.ResolveUnreachable (ec, true))
3003 if (!ss.Block.Resolve (ec))
3008 if (default_section == null)
3009 ec.CurrentBranching.CreateSibling (
3010 null, FlowBranching.SiblingType.SwitchSection);
3012 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
3013 ec.Switch = old_switch;
3015 Report.Debug (1, "END OF SWITCH BLOCK", loc, ec.CurrentBranching,
3021 protected override void DoEmit (EmitContext ec)
3023 ILGenerator ig = ec.ig;
3025 // Store variable for comparission purposes
3028 value = ig.DeclareLocal (SwitchType);
3030 ig.Emit (OpCodes.Stloc, value);
3034 default_target = ig.DefineLabel ();
3037 // Setup the codegen context
3039 Label old_end = ec.LoopEnd;
3040 Switch old_switch = ec.Switch;
3042 ec.LoopEnd = ig.DefineLabel ();
3047 if (constant_section != null)
3048 constant_section.Block.Emit (ec);
3049 } else if (SwitchType == TypeManager.string_type)
3050 SimpleSwitchEmit (ec, value);
3052 TableSwitchEmit (ec, value);
3054 // Restore context state.
3055 ig.MarkLabel (ec.LoopEnd);
3058 // Restore the previous context
3060 ec.LoopEnd = old_end;
3061 ec.Switch = old_switch;
3065 public abstract class ExceptionStatement : Statement
3067 public abstract void EmitFinally (EmitContext ec);
3069 protected bool emit_finally = true;
3070 ArrayList parent_vectors;
3072 protected void DoEmitFinally (EmitContext ec)
3075 ec.ig.BeginFinallyBlock ();
3076 else if (ec.InIterator)
3077 ec.CurrentIterator.MarkFinally (ec, parent_vectors);
3081 protected void ResolveFinally (FlowBranchingException branching)
3083 emit_finally = branching.EmitFinally;
3085 branching.Parent.StealFinallyClauses (ref parent_vectors);
3089 public class Lock : ExceptionStatement {
3091 public Statement Statement;
3092 TemporaryVariable temp;
3094 public Lock (Expression expr, Statement stmt, Location l)
3101 public override bool Resolve (EmitContext ec)
3103 expr = expr.Resolve (ec);
3107 if (expr.Type.IsValueType){
3108 Report.Error (185, loc,
3109 "`{0}' is not a reference type as required by the lock statement",
3110 TypeManager.CSharpName (expr.Type));
3114 FlowBranchingException branching = ec.StartFlowBranching (this);
3115 bool ok = Statement.Resolve (ec);
3117 ec.KillFlowBranching ();
3121 ResolveFinally (branching);
3123 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
3124 if (reachability.Returns != FlowBranching.FlowReturns.Always) {
3125 // Unfortunately, System.Reflection.Emit automatically emits
3126 // a leave to the end of the finally block.
3127 // This is a problem if `returns' is true since we may jump
3128 // to a point after the end of the method.
3129 // As a workaround, emit an explicit ret here.
3130 ec.NeedReturnLabel ();
3133 temp = new TemporaryVariable (expr.Type, loc);
3139 protected override void DoEmit (EmitContext ec)
3141 ILGenerator ig = ec.ig;
3143 temp.Store (ec, expr);
3145 ig.Emit (OpCodes.Call, TypeManager.void_monitor_enter_object);
3149 ig.BeginExceptionBlock ();
3150 Statement.Emit (ec);
3155 ig.EndExceptionBlock ();
3158 public override void EmitFinally (EmitContext ec)
3161 ec.ig.Emit (OpCodes.Call, TypeManager.void_monitor_exit_object);
3165 public class Unchecked : Statement {
3166 public readonly Block Block;
3168 public Unchecked (Block b)
3174 public override bool Resolve (EmitContext ec)
3176 bool previous_state = ec.CheckState;
3177 bool previous_state_const = ec.ConstantCheckState;
3179 ec.CheckState = false;
3180 ec.ConstantCheckState = false;
3181 bool ret = Block.Resolve (ec);
3182 ec.CheckState = previous_state;
3183 ec.ConstantCheckState = previous_state_const;
3188 protected override void DoEmit (EmitContext ec)
3190 bool previous_state = ec.CheckState;
3191 bool previous_state_const = ec.ConstantCheckState;
3193 ec.CheckState = false;
3194 ec.ConstantCheckState = false;
3196 ec.CheckState = previous_state;
3197 ec.ConstantCheckState = previous_state_const;
3201 public class Checked : Statement {
3202 public readonly Block Block;
3204 public Checked (Block b)
3207 b.Unchecked = false;
3210 public override bool Resolve (EmitContext ec)
3212 bool previous_state = ec.CheckState;
3213 bool previous_state_const = ec.ConstantCheckState;
3215 ec.CheckState = true;
3216 ec.ConstantCheckState = true;
3217 bool ret = Block.Resolve (ec);
3218 ec.CheckState = previous_state;
3219 ec.ConstantCheckState = previous_state_const;
3224 protected override void DoEmit (EmitContext ec)
3226 bool previous_state = ec.CheckState;
3227 bool previous_state_const = ec.ConstantCheckState;
3229 ec.CheckState = true;
3230 ec.ConstantCheckState = true;
3232 ec.CheckState = previous_state;
3233 ec.ConstantCheckState = previous_state_const;
3237 public class Unsafe : Statement {
3238 public readonly Block Block;
3240 public Unsafe (Block b)
3243 Block.Unsafe = true;
3246 public override bool Resolve (EmitContext ec)
3248 bool previous_state = ec.InUnsafe;
3252 val = Block.Resolve (ec);
3253 ec.InUnsafe = previous_state;
3258 protected override void DoEmit (EmitContext ec)
3260 bool previous_state = ec.InUnsafe;
3264 ec.InUnsafe = previous_state;
3271 public class Fixed : Statement {
3273 ArrayList declarators;
3274 Statement statement;
3279 abstract class Emitter
3281 protected LocalInfo vi;
3282 protected Expression converted;
3284 protected Emitter (Expression expr, LocalInfo li)
3290 public abstract void Emit (EmitContext ec);
3291 public abstract void EmitExit (ILGenerator ig);
3294 class ExpressionEmitter : Emitter {
3295 public ExpressionEmitter (Expression converted, LocalInfo li) :
3296 base (converted, li)
3300 public override void Emit (EmitContext ec) {
3302 // Store pointer in pinned location
3304 converted.Emit (ec);
3305 ec.ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
3308 public override void EmitExit (ILGenerator ig)
3310 ig.Emit (OpCodes.Ldc_I4_0);
3311 ig.Emit (OpCodes.Conv_U);
3312 ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
3316 class StringEmitter : Emitter {
3317 LocalBuilder pinned_string;
3320 public StringEmitter (Expression expr, LocalInfo li, Location loc):
3326 public override void Emit (EmitContext ec)
3328 ILGenerator ig = ec.ig;
3329 pinned_string = TypeManager.DeclareLocalPinned (ig, TypeManager.string_type);
3331 converted.Emit (ec);
3332 ig.Emit (OpCodes.Stloc, pinned_string);
3334 Expression sptr = new StringPtr (pinned_string, loc);
3335 converted = Convert.ImplicitConversionRequired (
3336 ec, sptr, vi.VariableType, loc);
3338 if (converted == null)
3341 converted.Emit (ec);
3342 ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
3345 public override void EmitExit(ILGenerator ig)
3347 ig.Emit (OpCodes.Ldnull);
3348 ig.Emit (OpCodes.Stloc, pinned_string);
3352 public Fixed (Expression type, ArrayList decls, Statement stmt, Location l)
3355 declarators = decls;
3360 public Statement Statement {
3361 get { return statement; }
3364 public override bool Resolve (EmitContext ec)
3367 Expression.UnsafeError (loc);
3371 TypeExpr texpr = type.ResolveAsTypeTerminal (ec, false);
3375 expr_type = texpr.ResolveType (ec);
3377 data = new Emitter [declarators.Count];
3379 if (!expr_type.IsPointer){
3380 Report.Error (209, loc, "The type of locals declared in a fixed statement must be a pointer type");
3385 foreach (Pair p in declarators){
3386 LocalInfo vi = (LocalInfo) p.First;
3387 Expression e = (Expression) p.Second;
3389 vi.VariableInfo.SetAssigned (ec);
3390 vi.SetReadOnlyContext (LocalInfo.ReadOnlyContext.Fixed);
3393 // The rules for the possible declarators are pretty wise,
3394 // but the production on the grammar is more concise.
3396 // So we have to enforce these rules here.
3398 // We do not resolve before doing the case 1 test,
3399 // because the grammar is explicit in that the token &
3400 // is present, so we need to test for this particular case.
3404 Report.Error (254, loc, "The right hand side of a fixed statement assignment may not be a cast expression");
3409 // Case 1: & object.
3411 if (e is Unary && ((Unary) e).Oper == Unary.Operator.AddressOf){
3412 Expression child = ((Unary) e).Expr;
3414 if (child is ParameterReference || child is LocalVariableReference){
3417 "No need to use fixed statement for parameters or " +
3418 "local variable declarations (address is already " +
3423 ec.InFixedInitializer = true;
3425 ec.InFixedInitializer = false;
3429 child = ((Unary) e).Expr;
3431 if (!TypeManager.VerifyUnManaged (child.Type, loc))
3434 if (!Convert.ImplicitConversionExists (ec, e, expr_type)) {
3435 e.Error_ValueCannotBeConverted (e.Location, expr_type, false);
3439 data [i] = new ExpressionEmitter (e, vi);
3445 ec.InFixedInitializer = true;
3447 ec.InFixedInitializer = false;
3454 if (e.Type.IsArray){
3455 Type array_type = TypeManager.GetElementType (e.Type);
3458 // Provided that array_type is unmanaged,
3460 if (!TypeManager.VerifyUnManaged (array_type, loc))
3464 // and T* is implicitly convertible to the
3465 // pointer type given in the fixed statement.
3467 ArrayPtr array_ptr = new ArrayPtr (e, array_type, loc);
3469 Expression converted = Convert.ImplicitConversionRequired (
3470 ec, array_ptr, vi.VariableType, loc);
3471 if (converted == null)
3474 data [i] = new ExpressionEmitter (converted, vi);
3483 if (e.Type == TypeManager.string_type){
3484 data [i] = new StringEmitter (e, vi, loc);
3489 // Case 4: fixed buffer
3490 FieldExpr fe = e as FieldExpr;
3492 IFixedBuffer ff = AttributeTester.GetFixedBuffer (fe.FieldInfo);
3494 Expression fixed_buffer_ptr = new FixedBufferPtr (fe, ff.ElementType, loc);
3496 Expression converted = Convert.ImplicitConversionRequired (
3497 ec, fixed_buffer_ptr, vi.VariableType, loc);
3498 if (converted == null)
3501 data [i] = new ExpressionEmitter (converted, vi);
3509 // For other cases, flag a `this is already fixed expression'
3511 if (e is LocalVariableReference || e is ParameterReference ||
3512 Convert.ImplicitConversionExists (ec, e, vi.VariableType)){
3514 Report.Error (245, loc, "right hand expression is already fixed, no need to use fixed statement ");
3518 Report.Error (245, loc, "Fixed statement only allowed on strings, arrays or address-of expressions");
3522 ec.StartFlowBranching (FlowBranching.BranchingType.Conditional, loc);
3524 if (!statement.Resolve (ec)) {
3525 ec.KillFlowBranching ();
3529 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
3530 has_ret = reachability.IsUnreachable;
3535 protected override void DoEmit (EmitContext ec)
3537 for (int i = 0; i < data.Length; i++) {
3541 statement.Emit (ec);
3546 ILGenerator ig = ec.ig;
3549 // Clear the pinned variable
3551 for (int i = 0; i < data.Length; i++) {
3552 data [i].EmitExit (ig);
3557 public class Catch : Statement {
3558 public readonly string Name;
3559 public readonly Block Block;
3561 Expression type_expr;
3564 public Catch (Expression type, string name, Block block, Location l)
3572 public Type CatchType {
3578 public bool IsGeneral {
3580 return type_expr == null;
3584 protected override void DoEmit(EmitContext ec)
3588 public override bool Resolve (EmitContext ec)
3590 bool was_catch = ec.InCatch;
3593 if (type_expr != null) {
3594 TypeExpr te = type_expr.ResolveAsTypeTerminal (ec, false);
3598 type = te.ResolveType (ec);
3600 if (type != TypeManager.exception_type && !type.IsSubclassOf (TypeManager.exception_type)){
3601 Error (155, "The type caught or thrown must be derived from System.Exception");
3607 return Block.Resolve (ec);
3610 ec.InCatch = was_catch;
3615 public class Try : ExceptionStatement {
3616 public readonly Block Fini, Block;
3617 public readonly ArrayList Specific;
3618 public readonly Catch General;
3620 bool need_exc_block;
3623 // specific, general and fini might all be null.
3625 public Try (Block block, ArrayList specific, Catch general, Block fini, Location l)
3627 if (specific == null && general == null){
3628 Console.WriteLine ("CIR.Try: Either specific or general have to be non-null");
3632 this.Specific = specific;
3633 this.General = general;
3638 public override bool Resolve (EmitContext ec)
3642 FlowBranchingException branching = ec.StartFlowBranching (this);
3644 Report.Debug (1, "START OF TRY BLOCK", Block.StartLocation);
3646 if (!Block.Resolve (ec))
3649 FlowBranching.UsageVector vector = ec.CurrentBranching.CurrentUsageVector;
3651 Report.Debug (1, "START OF CATCH BLOCKS", vector);
3653 Type[] prevCatches = new Type [Specific.Count];
3655 foreach (Catch c in Specific){
3656 ec.CurrentBranching.CreateSibling (
3657 c.Block, FlowBranching.SiblingType.Catch);
3659 Report.Debug (1, "STARTED SIBLING FOR CATCH", ec.CurrentBranching);
3661 if (c.Name != null) {
3662 LocalInfo vi = c.Block.GetLocalInfo (c.Name);
3664 throw new Exception ();
3666 vi.VariableInfo = null;
3669 if (!c.Resolve (ec))
3672 Type resolvedType = c.CatchType;
3673 for (int ii = 0; ii < last_index; ++ii) {
3674 if (resolvedType == prevCatches [ii] || resolvedType.IsSubclassOf (prevCatches [ii])) {
3675 Report.Error (160, c.loc, "A previous catch clause already catches all exceptions of this or a super type `{0}'", prevCatches [ii].FullName);
3680 prevCatches [last_index++] = resolvedType;
3681 need_exc_block = true;
3684 Report.Debug (1, "END OF CATCH BLOCKS", ec.CurrentBranching);
3686 if (General != null){
3687 if (CodeGen.Assembly.WrapNonExceptionThrows) {
3688 foreach (Catch c in Specific){
3689 if (c.CatchType == TypeManager.exception_type) {
3690 Report.Warning (1058, 1, c.loc, "A previous catch clause already catches all exceptions. All non-exceptions thrown will be wrapped in a `System.Runtime.CompilerServices.RuntimeWrappedException'");
3695 ec.CurrentBranching.CreateSibling (
3696 General.Block, FlowBranching.SiblingType.Catch);
3698 Report.Debug (1, "STARTED SIBLING FOR GENERAL", ec.CurrentBranching);
3700 if (!General.Resolve (ec))
3703 need_exc_block = true;
3706 Report.Debug (1, "END OF GENERAL CATCH BLOCKS", ec.CurrentBranching);
3710 ec.CurrentBranching.CreateSibling (
3711 Fini, FlowBranching.SiblingType.Finally);
3713 Report.Debug (1, "STARTED SIBLING FOR FINALLY", ec.CurrentBranching, vector);
3714 bool was_finally = ec.InFinally;
3715 ec.InFinally = true;
3716 if (!Fini.Resolve (ec))
3718 ec.InFinally = was_finally;
3721 need_exc_block = true;
3724 if (ec.InIterator) {
3725 ResolveFinally (branching);
3726 need_exc_block |= emit_finally;
3728 emit_finally = Fini != null;
3730 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
3732 FlowBranching.UsageVector f_vector = ec.CurrentBranching.CurrentUsageVector;
3734 Report.Debug (1, "END OF TRY", ec.CurrentBranching, reachability, vector, f_vector);
3736 if (reachability.Returns != FlowBranching.FlowReturns.Always) {
3737 // Unfortunately, System.Reflection.Emit automatically emits
3738 // a leave to the end of the finally block. This is a problem
3739 // if `returns' is true since we may jump to a point after the
3740 // end of the method.
3741 // As a workaround, emit an explicit ret here.
3742 ec.NeedReturnLabel ();
3748 protected override void DoEmit (EmitContext ec)
3750 ILGenerator ig = ec.ig;
3753 ig.BeginExceptionBlock ();
3756 foreach (Catch c in Specific){
3759 ig.BeginCatchBlock (c.CatchType);
3761 if (c.Name != null){
3762 vi = c.Block.GetLocalInfo (c.Name);
3764 throw new Exception ("Variable does not exist in this block");
3766 ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
3768 ec.EmitCapturedVariableInstance (vi);
3769 ig.Emit (OpCodes.Ldloc, vi.LocalBuilder);
3770 ig.Emit (OpCodes.Stfld, vi.FieldBuilder);
3773 ig.Emit (OpCodes.Pop);
3778 if (General != null){
3779 ig.BeginCatchBlock (TypeManager.object_type);
3780 ig.Emit (OpCodes.Pop);
3781 General.Block.Emit (ec);
3786 ig.EndExceptionBlock ();
3789 public override void EmitFinally (EmitContext ec)
3795 public bool HasCatch
3798 return General != null || Specific.Count > 0;
3803 public class Using : ExceptionStatement {
3804 object expression_or_block;
3805 public Statement Statement;
3809 Expression [] resolved_vars;
3810 Expression [] converted_vars;
3811 ExpressionStatement [] assign;
3812 LocalBuilder local_copy;
3814 public Using (object expression_or_block, Statement stmt, Location l)
3816 this.expression_or_block = expression_or_block;
3822 // Resolves for the case of using using a local variable declaration.
3824 bool ResolveLocalVariableDecls (EmitContext ec)
3828 TypeExpr texpr = expr.ResolveAsTypeTerminal (ec, false);
3832 expr_type = texpr.ResolveType (ec);
3835 // The type must be an IDisposable or an implicit conversion
3838 converted_vars = new Expression [var_list.Count];
3839 resolved_vars = new Expression [var_list.Count];
3840 assign = new ExpressionStatement [var_list.Count];
3842 bool need_conv = !TypeManager.ImplementsInterface (
3843 expr_type, TypeManager.idisposable_type);
3845 foreach (DictionaryEntry e in var_list){
3846 Expression var = (Expression) e.Key;
3848 var = var.ResolveLValue (ec, new EmptyExpression (), loc);
3852 resolved_vars [i] = var;
3859 converted_vars [i] = Convert.ImplicitConversion (
3860 ec, var, TypeManager.idisposable_type, loc);
3862 if (converted_vars [i] == null) {
3863 Error_IsNotConvertibleToIDisposable ();
3871 foreach (DictionaryEntry e in var_list){
3872 Expression var = resolved_vars [i];
3873 Expression new_expr = (Expression) e.Value;
3876 a = new Assign (var, new_expr, loc);
3882 converted_vars [i] = var;
3883 assign [i] = (ExpressionStatement) a;
3890 void Error_IsNotConvertibleToIDisposable ()
3892 Report.Error (1674, loc, "`{0}': type used in a using statement must be implicitly convertible to `System.IDisposable'",
3893 TypeManager.CSharpName (expr_type));
3896 bool ResolveExpression (EmitContext ec)
3898 if (!TypeManager.ImplementsInterface (expr_type, TypeManager.idisposable_type)){
3899 if (Convert.ImplicitConversion (ec, expr, TypeManager.idisposable_type, loc) == null) {
3900 Error_IsNotConvertibleToIDisposable ();
3909 // Emits the code for the case of using using a local variable declaration.
3911 void EmitLocalVariableDecls (EmitContext ec)
3913 ILGenerator ig = ec.ig;
3916 for (i = 0; i < assign.Length; i++) {
3917 assign [i].EmitStatement (ec);
3920 ig.BeginExceptionBlock ();
3922 Statement.Emit (ec);
3923 var_list.Reverse ();
3928 void EmitLocalVariableDeclFinally (EmitContext ec)
3930 ILGenerator ig = ec.ig;
3932 int i = assign.Length;
3933 for (int ii = 0; ii < var_list.Count; ++ii){
3934 Expression var = resolved_vars [--i];
3935 Label skip = ig.DefineLabel ();
3937 if (!var.Type.IsValueType) {
3939 ig.Emit (OpCodes.Brfalse, skip);
3940 converted_vars [i].Emit (ec);
3941 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
3943 Expression ml = Expression.MemberLookup(ec, TypeManager.idisposable_type, var.Type, "Dispose", Mono.CSharp.Location.Null);
3945 if (!(ml is MethodGroupExpr)) {
3947 ig.Emit (OpCodes.Box, var.Type);
3948 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
3950 MethodInfo mi = null;
3952 foreach (MethodInfo mk in ((MethodGroupExpr) ml).Methods) {
3953 if (TypeManager.GetArgumentTypes (mk).Length == 0) {
3960 Report.Error(-100, Mono.CSharp.Location.Null, "Internal error: No Dispose method which takes 0 parameters.");
3964 IMemoryLocation mloc = (IMemoryLocation) var;
3966 mloc.AddressOf (ec, AddressOp.Load);
3967 ig.Emit (OpCodes.Call, mi);
3971 ig.MarkLabel (skip);
3974 ig.EndExceptionBlock ();
3976 ig.BeginFinallyBlock ();
3981 void EmitExpression (EmitContext ec)
3984 // Make a copy of the expression and operate on that.
3986 ILGenerator ig = ec.ig;
3987 local_copy = ig.DeclareLocal (expr_type);
3990 ig.Emit (OpCodes.Stloc, local_copy);
3993 ig.BeginExceptionBlock ();
3995 Statement.Emit (ec);
3999 ig.EndExceptionBlock ();
4002 void EmitExpressionFinally (EmitContext ec)
4004 ILGenerator ig = ec.ig;
4005 if (!local_copy.LocalType.IsValueType) {
4006 Label skip = ig.DefineLabel ();
4007 ig.Emit (OpCodes.Ldloc, local_copy);
4008 ig.Emit (OpCodes.Brfalse, skip);
4009 ig.Emit (OpCodes.Ldloc, local_copy);
4010 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4011 ig.MarkLabel (skip);
4013 Expression ml = Expression.MemberLookup(ec, TypeManager.idisposable_type, local_copy.LocalType, "Dispose", Mono.CSharp.Location.Null);
4015 if (!(ml is MethodGroupExpr)) {
4016 ig.Emit (OpCodes.Ldloc, local_copy);
4017 ig.Emit (OpCodes.Box, local_copy.LocalType);
4018 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4020 MethodInfo mi = null;
4022 foreach (MethodInfo mk in ((MethodGroupExpr) ml).Methods) {
4023 if (TypeManager.GetArgumentTypes (mk).Length == 0) {
4030 Report.Error(-100, Mono.CSharp.Location.Null, "Internal error: No Dispose method which takes 0 parameters.");
4034 ig.Emit (OpCodes.Ldloca, local_copy);
4035 ig.Emit (OpCodes.Call, mi);
4040 public override bool Resolve (EmitContext ec)
4042 if (expression_or_block is DictionaryEntry){
4043 expr = (Expression) ((DictionaryEntry) expression_or_block).Key;
4044 var_list = (ArrayList)((DictionaryEntry)expression_or_block).Value;
4046 if (!ResolveLocalVariableDecls (ec))
4049 } else if (expression_or_block is Expression){
4050 expr = (Expression) expression_or_block;
4052 expr = expr.Resolve (ec);
4056 expr_type = expr.Type;
4058 if (!ResolveExpression (ec))
4062 FlowBranchingException branching = ec.StartFlowBranching (this);
4064 bool ok = Statement.Resolve (ec);
4067 ec.KillFlowBranching ();
4071 ResolveFinally (branching);
4072 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
4074 if (reachability.Returns != FlowBranching.FlowReturns.Always) {
4075 // Unfortunately, System.Reflection.Emit automatically emits a leave
4076 // to the end of the finally block. This is a problem if `returns'
4077 // is true since we may jump to a point after the end of the method.
4078 // As a workaround, emit an explicit ret here.
4079 ec.NeedReturnLabel ();
4085 protected override void DoEmit (EmitContext ec)
4087 if (expression_or_block is DictionaryEntry)
4088 EmitLocalVariableDecls (ec);
4089 else if (expression_or_block is Expression)
4090 EmitExpression (ec);
4093 public override void EmitFinally (EmitContext ec)
4095 if (expression_or_block is DictionaryEntry)
4096 EmitLocalVariableDeclFinally (ec);
4097 else if (expression_or_block is Expression)
4098 EmitExpressionFinally (ec);
4103 /// Implementation of the foreach C# statement
4105 public class Foreach : Statement {
4107 Expression variable;
4109 Statement statement;
4111 CollectionForeach collection;
4113 public Foreach (Expression type, LocalVariableReference var, Expression expr,
4114 Statement stmt, Location l)
4117 this.variable = var;
4123 public Statement Statement {
4124 get { return statement; }
4127 public override bool Resolve (EmitContext ec)
4129 expr = expr.Resolve (ec);
4133 if (expr is NullLiteral) {
4134 Report.Error (186, loc, "Use of null is not valid in this context");
4138 TypeExpr texpr = type.ResolveAsTypeTerminal (ec, false);
4142 Type var_type = texpr.Type;
4144 if (expr.eclass == ExprClass.MethodGroup || expr is AnonymousMethod) {
4145 Report.Error (446, expr.Location, "Foreach statement cannot operate on a `{0}'",
4146 expr.ExprClassName);
4151 // We need an instance variable. Not sure this is the best
4152 // way of doing this.
4154 // FIXME: When we implement propertyaccess, will those turn
4155 // out to return values in ExprClass? I think they should.
4157 if (!(expr.eclass == ExprClass.Variable || expr.eclass == ExprClass.Value ||
4158 expr.eclass == ExprClass.PropertyAccess || expr.eclass == ExprClass.IndexerAccess)){
4159 collection.Error_Enumerator ();
4163 if (expr.Type.IsArray) {
4164 array = new ArrayForeach (var_type, variable, expr, statement, loc);
4165 return array.Resolve (ec);
4167 collection = new CollectionForeach (
4168 var_type, variable, expr, statement, loc);
4169 return collection.Resolve (ec);
4173 protected override void DoEmit (EmitContext ec)
4175 ILGenerator ig = ec.ig;
4177 Label old_begin = ec.LoopBegin, old_end = ec.LoopEnd;
4178 ec.LoopBegin = ig.DefineLabel ();
4179 ec.LoopEnd = ig.DefineLabel ();
4181 if (collection != null)
4182 collection.Emit (ec);
4186 ec.LoopBegin = old_begin;
4187 ec.LoopEnd = old_end;
4190 protected class ArrayCounter : TemporaryVariable
4192 public ArrayCounter (Location loc)
4193 : base (TypeManager.int32_type, loc)
4196 public void Initialize (EmitContext ec)
4199 ec.ig.Emit (OpCodes.Ldc_I4_0);
4203 public void Increment (EmitContext ec)
4207 ec.ig.Emit (OpCodes.Ldc_I4_1);
4208 ec.ig.Emit (OpCodes.Add);
4213 protected class ArrayForeach : Statement
4215 Expression variable, expr, conv;
4216 Statement statement;
4219 TemporaryVariable[] lengths;
4220 ArrayCounter[] counter;
4223 TemporaryVariable copy;
4226 public ArrayForeach (Type var_type, Expression var,
4227 Expression expr, Statement stmt, Location l)
4229 this.var_type = var_type;
4230 this.variable = var;
4236 public override bool Resolve (EmitContext ec)
4238 array_type = expr.Type;
4239 rank = array_type.GetArrayRank ();
4241 copy = new TemporaryVariable (array_type, loc);
4244 counter = new ArrayCounter [rank];
4245 lengths = new TemporaryVariable [rank];
4247 ArrayList list = new ArrayList ();
4248 for (int i = 0; i < rank; i++) {
4249 counter [i] = new ArrayCounter (loc);
4250 counter [i].Resolve (ec);
4252 lengths [i] = new TemporaryVariable (TypeManager.int32_type, loc);
4253 lengths [i].Resolve (ec);
4255 list.Add (counter [i]);
4258 access = new ElementAccess (copy, list).Resolve (ec);
4262 conv = Convert.ExplicitConversion (ec, access, var_type, loc);
4268 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
4269 ec.CurrentBranching.CreateSibling ();
4271 variable = variable.ResolveLValue (ec, conv, loc);
4272 if (variable == null)
4275 if (!statement.Resolve (ec))
4278 ec.EndFlowBranching ();
4283 protected override void DoEmit (EmitContext ec)
4285 ILGenerator ig = ec.ig;
4287 copy.Store (ec, expr);
4289 Label[] test = new Label [rank];
4290 Label[] loop = new Label [rank];
4292 for (int i = 0; i < rank; i++) {
4293 test [i] = ig.DefineLabel ();
4294 loop [i] = ig.DefineLabel ();
4296 lengths [i].EmitThis (ec);
4297 ((ArrayAccess) access).EmitGetLength (ec, i);
4298 lengths [i].EmitStore (ig);
4301 for (int i = 0; i < rank; i++) {
4302 counter [i].Initialize (ec);
4304 ig.Emit (OpCodes.Br, test [i]);
4305 ig.MarkLabel (loop [i]);
4308 ((IAssignMethod) variable).EmitAssign (ec, conv, false, false);
4310 statement.Emit (ec);
4312 ig.MarkLabel (ec.LoopBegin);
4314 for (int i = rank - 1; i >= 0; i--){
4315 counter [i].Increment (ec);
4317 ig.MarkLabel (test [i]);
4318 counter [i].Emit (ec);
4319 lengths [i].Emit (ec);
4320 ig.Emit (OpCodes.Blt, loop [i]);
4323 ig.MarkLabel (ec.LoopEnd);
4327 protected class CollectionForeach : ExceptionStatement
4329 Expression variable, expr;
4330 Statement statement;
4332 TemporaryVariable enumerator;
4336 MethodGroupExpr get_enumerator;
4337 PropertyExpr get_current;
4338 MethodInfo move_next;
4339 Type var_type, enumerator_type;
4341 bool enumerator_found;
4343 public CollectionForeach (Type var_type, Expression var,
4344 Expression expr, Statement stmt, Location l)
4346 this.var_type = var_type;
4347 this.variable = var;
4353 bool GetEnumeratorFilter (EmitContext ec, MethodInfo mi)
4355 Type return_type = mi.ReturnType;
4357 if ((return_type == TypeManager.ienumerator_type) && (mi.DeclaringType == TypeManager.string_type))
4359 // Apply the same optimization as MS: skip the GetEnumerator
4360 // returning an IEnumerator, and use the one returning a
4361 // CharEnumerator instead. This allows us to avoid the
4362 // try-finally block and the boxing.
4367 // Ok, we can access it, now make sure that we can do something
4368 // with this `GetEnumerator'
4371 if (return_type == TypeManager.ienumerator_type ||
4372 TypeManager.ienumerator_type.IsAssignableFrom (return_type) ||
4373 (!RootContext.StdLib && TypeManager.ImplementsInterface (return_type, TypeManager.ienumerator_type))) {
4375 // If it is not an interface, lets try to find the methods ourselves.
4376 // For example, if we have:
4377 // public class Foo : IEnumerator { public bool MoveNext () {} public int Current { get {}}}
4378 // We can avoid the iface call. This is a runtime perf boost.
4379 // even bigger if we have a ValueType, because we avoid the cost
4382 // We have to make sure that both methods exist for us to take
4383 // this path. If one of the methods does not exist, we will just
4384 // use the interface. Sadly, this complex if statement is the only
4385 // way I could do this without a goto
4388 if (return_type.IsInterface ||
4389 !FetchMoveNext (ec, return_type) ||
4390 !FetchGetCurrent (ec, return_type)) {
4391 move_next = TypeManager.bool_movenext_void;
4392 get_current = new PropertyExpr (
4393 ec, TypeManager.ienumerator_getcurrent, loc);
4398 // Ok, so they dont return an IEnumerable, we will have to
4399 // find if they support the GetEnumerator pattern.
4402 if (TypeManager.HasElementType (return_type) || !FetchMoveNext (ec, return_type) || !FetchGetCurrent (ec, return_type)) {
4403 Report.Error (202, loc, "foreach statement requires that the return type `{0}' of `{1}' must have a suitable public MoveNext method and public Current property",
4404 TypeManager.CSharpName (return_type), TypeManager.CSharpSignature (mi));
4409 enumerator_type = return_type;
4410 is_disposable = !enumerator_type.IsSealed ||
4411 TypeManager.ImplementsInterface (
4412 enumerator_type, TypeManager.idisposable_type);
4418 // Retrieves a `public bool MoveNext ()' method from the Type `t'
4420 bool FetchMoveNext (EmitContext ec, Type t)
4422 MemberList move_next_list;
4424 move_next_list = TypeContainer.FindMembers (
4425 t, MemberTypes.Method,
4426 BindingFlags.Public | BindingFlags.Instance,
4427 Type.FilterName, "MoveNext");
4428 if (move_next_list.Count == 0)
4431 foreach (MemberInfo m in move_next_list){
4432 MethodInfo mi = (MethodInfo) m;
4435 args = TypeManager.GetArgumentTypes (mi);
4436 if ((args != null) && (args.Length == 0) &&
4437 TypeManager.TypeToCoreType (mi.ReturnType) == TypeManager.bool_type) {
4447 // Retrieves a `public T get_Current ()' method from the Type `t'
4449 bool FetchGetCurrent (EmitContext ec, Type t)
4451 PropertyExpr pe = Expression.MemberLookup (
4452 ec, t, "Current", MemberTypes.Property,
4453 Expression.AllBindingFlags, loc) as PropertyExpr;
4462 // Retrieves a `public void Dispose ()' method from the Type `t'
4464 static MethodInfo FetchMethodDispose (Type t)
4466 MemberList dispose_list;
4468 dispose_list = TypeContainer.FindMembers (
4469 t, MemberTypes.Method,
4470 BindingFlags.Public | BindingFlags.Instance,
4471 Type.FilterName, "Dispose");
4472 if (dispose_list.Count == 0)
4475 foreach (MemberInfo m in dispose_list){
4476 MethodInfo mi = (MethodInfo) m;
4479 args = TypeManager.GetArgumentTypes (mi);
4480 if (args != null && args.Length == 0){
4481 if (mi.ReturnType == TypeManager.void_type)
4488 public void Error_Enumerator ()
4490 if (enumerator_found) {
4494 Report.Error (1579, loc,
4495 "foreach statement cannot operate on variables of type `{0}' because it does not contain a definition for `GetEnumerator' or is not accessible",
4496 TypeManager.CSharpName (expr.Type));
4499 bool TryType (EmitContext ec, Type t)
4501 MethodGroupExpr mg = Expression.MemberLookup (
4502 ec, t, "GetEnumerator", MemberTypes.Method,
4503 Expression.AllBindingFlags, loc) as MethodGroupExpr;
4507 foreach (MethodBase mb in mg.Methods) {
4508 Type [] args = TypeManager.GetArgumentTypes (mb);
4509 if (args != null && args.Length != 0)
4512 // Check whether GetEnumerator is public
4513 if ((mb.Attributes & MethodAttributes.Public) != MethodAttributes.Public)
4516 if (TypeManager.IsOverride (mb))
4519 enumerator_found = true;
4521 if (!GetEnumeratorFilter (ec, (MethodInfo) mb))
4524 MethodInfo[] mi = new MethodInfo[] { (MethodInfo) mb };
4525 get_enumerator = new MethodGroupExpr (mi, loc);
4527 if (t != expr.Type) {
4528 expr = Convert.ExplicitConversion (
4531 throw new InternalErrorException ();
4534 get_enumerator.InstanceExpression = expr;
4535 get_enumerator.IsBase = t != expr.Type;
4543 bool ProbeCollectionType (EmitContext ec, Type t)
4545 for (Type tt = t; tt != null && tt != TypeManager.object_type;){
4546 if (TryType (ec, tt))
4552 // Now try to find the method in the interfaces
4555 Type [] ifaces = t.GetInterfaces ();
4557 foreach (Type i in ifaces){
4558 if (TryType (ec, i))
4563 // Since TypeBuilder.GetInterfaces only returns the interface
4564 // types for this type, we have to keep looping, but once
4565 // we hit a non-TypeBuilder (ie, a Type), then we know we are
4566 // done, because it returns all the types
4568 if ((t is TypeBuilder))
4577 public override bool Resolve (EmitContext ec)
4579 enumerator_type = TypeManager.ienumerator_type;
4580 is_disposable = true;
4582 if (!ProbeCollectionType (ec, expr.Type)) {
4583 Error_Enumerator ();
4587 enumerator = new TemporaryVariable (enumerator_type, loc);
4588 enumerator.Resolve (ec);
4590 init = new Invocation (get_enumerator, new ArrayList ());
4591 init = init.Resolve (ec);
4595 Expression move_next_expr;
4597 MemberInfo[] mi = new MemberInfo[] { move_next };
4598 MethodGroupExpr mg = new MethodGroupExpr (mi, loc);
4599 mg.InstanceExpression = enumerator;
4601 move_next_expr = new Invocation (mg, new ArrayList ());
4604 get_current.InstanceExpression = enumerator;
4606 Statement block = new CollectionForeachStatement (
4607 var_type, variable, get_current, statement, loc);
4609 loop = new While (move_next_expr, block, loc);
4613 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
4614 ec.CurrentBranching.CreateSibling ();
4616 FlowBranchingException branching = null;
4618 branching = ec.StartFlowBranching (this);
4620 if (!loop.Resolve (ec))
4623 if (is_disposable) {
4624 ResolveFinally (branching);
4625 ec.EndFlowBranching ();
4627 emit_finally = true;
4629 ec.EndFlowBranching ();
4634 protected override void DoEmit (EmitContext ec)
4636 ILGenerator ig = ec.ig;
4638 enumerator.Store (ec, init);
4641 // Protect the code in a try/finalize block, so that
4642 // if the beast implement IDisposable, we get rid of it
4644 if (is_disposable && emit_finally)
4645 ig.BeginExceptionBlock ();
4650 // Now the finally block
4652 if (is_disposable) {
4655 ig.EndExceptionBlock ();
4660 public override void EmitFinally (EmitContext ec)
4662 ILGenerator ig = ec.ig;
4664 if (enumerator_type.IsValueType) {
4665 enumerator.Emit (ec);
4667 MethodInfo mi = FetchMethodDispose (enumerator_type);
4669 enumerator.EmitLoadAddress (ec);
4670 ig.Emit (OpCodes.Call, mi);
4672 enumerator.Emit (ec);
4673 ig.Emit (OpCodes.Box, enumerator_type);
4674 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4677 Label call_dispose = ig.DefineLabel ();
4679 enumerator.Emit (ec);
4680 ig.Emit (OpCodes.Isinst, TypeManager.idisposable_type);
4681 ig.Emit (OpCodes.Dup);
4682 ig.Emit (OpCodes.Brtrue_S, call_dispose);
4683 ig.Emit (OpCodes.Pop);
4685 Label end_finally = ig.DefineLabel ();
4686 ig.Emit (OpCodes.Br, end_finally);
4688 ig.MarkLabel (call_dispose);
4689 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4690 ig.MarkLabel (end_finally);
4695 protected class CollectionForeachStatement : Statement
4698 Expression variable, current, conv;
4699 Statement statement;
4702 public CollectionForeachStatement (Type type, Expression variable,
4703 Expression current, Statement statement,
4707 this.variable = variable;
4708 this.current = current;
4709 this.statement = statement;
4713 public override bool Resolve (EmitContext ec)
4715 current = current.Resolve (ec);
4716 if (current == null)
4719 conv = Convert.ExplicitConversion (ec, current, type, loc);
4723 assign = new Assign (variable, conv, loc);
4724 if (assign.Resolve (ec) == null)
4727 if (!statement.Resolve (ec))
4733 protected override void DoEmit (EmitContext ec)
4735 assign.EmitStatement (ec);
4736 statement.Emit (ec);