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.
50 Report.Warning (162, 2, 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 public override bool ResolveUnreachable (EmitContext ec, bool warn)
106 protected override void DoEmit (EmitContext ec)
111 public class If : Statement {
113 public Statement TrueStatement;
114 public Statement FalseStatement;
118 public If (Expression expr, Statement trueStatement, Location l)
121 TrueStatement = trueStatement;
125 public If (Expression expr,
126 Statement trueStatement,
127 Statement falseStatement,
131 TrueStatement = trueStatement;
132 FalseStatement = falseStatement;
136 public override bool Resolve (EmitContext ec)
140 Report.Debug (1, "START IF BLOCK", loc);
142 expr = Expression.ResolveBoolean (ec, expr, loc);
148 Assign ass = expr as Assign;
149 if (ass != null && ass.Source is Constant) {
150 Report.Warning (665, 3, loc, "Assignment in conditional expression is always constant; did you mean to use == instead of = ?");
154 // Dead code elimination
156 if (expr is BoolConstant){
157 bool take = ((BoolConstant) expr).Value;
160 if (!TrueStatement.Resolve (ec))
163 if ((FalseStatement != null) &&
164 !FalseStatement.ResolveUnreachable (ec, true))
166 FalseStatement = null;
168 if (!TrueStatement.ResolveUnreachable (ec, true))
170 TrueStatement = null;
172 if ((FalseStatement != null) &&
173 !FalseStatement.Resolve (ec))
180 ec.StartFlowBranching (FlowBranching.BranchingType.Conditional, loc);
182 ok &= TrueStatement.Resolve (ec);
184 is_true_ret = ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable;
186 ec.CurrentBranching.CreateSibling ();
188 if (FalseStatement != null)
189 ok &= FalseStatement.Resolve (ec);
191 ec.EndFlowBranching ();
193 Report.Debug (1, "END IF BLOCK", loc);
198 protected override void DoEmit (EmitContext ec)
200 ILGenerator ig = ec.ig;
201 Label false_target = ig.DefineLabel ();
205 // If we're a boolean expression, Resolve() already
206 // eliminated dead code for us.
208 if (expr is BoolConstant){
209 bool take = ((BoolConstant) expr).Value;
212 TrueStatement.Emit (ec);
213 else if (FalseStatement != null)
214 FalseStatement.Emit (ec);
219 expr.EmitBranchable (ec, false_target, false);
221 TrueStatement.Emit (ec);
223 if (FalseStatement != null){
224 bool branch_emitted = false;
226 end = ig.DefineLabel ();
228 ig.Emit (OpCodes.Br, end);
229 branch_emitted = true;
232 ig.MarkLabel (false_target);
233 FalseStatement.Emit (ec);
238 ig.MarkLabel (false_target);
243 public class Do : Statement {
244 public Expression expr;
245 public readonly Statement EmbeddedStatement;
248 public Do (Statement statement, Expression boolExpr, Location l)
251 EmbeddedStatement = statement;
255 public override bool Resolve (EmitContext ec)
259 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
261 bool was_unreachable = ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable;
263 ec.StartFlowBranching (FlowBranching.BranchingType.Embedded, loc);
264 if (!EmbeddedStatement.Resolve (ec))
266 ec.EndFlowBranching ();
268 if (ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable && !was_unreachable)
269 Report.Warning (162, 2, expr.Location, "Unreachable code detected");
271 expr = Expression.ResolveBoolean (ec, expr, loc);
274 else if (expr is BoolConstant){
275 bool res = ((BoolConstant) expr).Value;
281 ec.CurrentBranching.CurrentUsageVector.Goto ();
283 ec.EndFlowBranching ();
288 protected override void DoEmit (EmitContext ec)
290 ILGenerator ig = ec.ig;
291 Label loop = ig.DefineLabel ();
292 Label old_begin = ec.LoopBegin;
293 Label old_end = ec.LoopEnd;
295 ec.LoopBegin = ig.DefineLabel ();
296 ec.LoopEnd = ig.DefineLabel ();
299 EmbeddedStatement.Emit (ec);
300 ig.MarkLabel (ec.LoopBegin);
303 // Dead code elimination
305 if (expr is BoolConstant){
306 bool res = ((BoolConstant) expr).Value;
309 ec.ig.Emit (OpCodes.Br, loop);
311 expr.EmitBranchable (ec, loop, true);
313 ig.MarkLabel (ec.LoopEnd);
315 ec.LoopBegin = old_begin;
316 ec.LoopEnd = old_end;
320 public class While : Statement {
321 public Expression expr;
322 public readonly Statement Statement;
323 bool infinite, empty;
325 public While (Expression boolExpr, Statement statement, Location l)
327 this.expr = boolExpr;
328 Statement = statement;
332 public override bool Resolve (EmitContext ec)
336 expr = Expression.ResolveBoolean (ec, expr, loc);
341 // Inform whether we are infinite or not
343 if (expr is BoolConstant){
344 BoolConstant bc = (BoolConstant) expr;
346 if (bc.Value == false){
347 if (!Statement.ResolveUnreachable (ec, true))
355 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
357 ec.CurrentBranching.CreateSibling ();
359 ec.StartFlowBranching (FlowBranching.BranchingType.Embedded, loc);
360 if (!Statement.Resolve (ec))
362 ec.EndFlowBranching ();
364 // There's no direct control flow from the end of the embedded statement to the end of the loop
365 ec.CurrentBranching.CurrentUsageVector.Goto ();
367 ec.EndFlowBranching ();
372 protected override void DoEmit (EmitContext ec)
377 ILGenerator ig = ec.ig;
378 Label old_begin = ec.LoopBegin;
379 Label old_end = ec.LoopEnd;
381 ec.LoopBegin = ig.DefineLabel ();
382 ec.LoopEnd = ig.DefineLabel ();
385 // Inform whether we are infinite or not
387 if (expr is BoolConstant){
388 ig.MarkLabel (ec.LoopBegin);
390 ig.Emit (OpCodes.Br, ec.LoopBegin);
393 // Inform that we are infinite (ie, `we return'), only
394 // if we do not `break' inside the code.
396 ig.MarkLabel (ec.LoopEnd);
398 Label while_loop = ig.DefineLabel ();
400 ig.Emit (OpCodes.Br, ec.LoopBegin);
401 ig.MarkLabel (while_loop);
405 ig.MarkLabel (ec.LoopBegin);
407 expr.EmitBranchable (ec, while_loop, true);
409 ig.MarkLabel (ec.LoopEnd);
412 ec.LoopBegin = old_begin;
413 ec.LoopEnd = old_end;
417 public class For : Statement {
419 readonly Statement InitStatement;
420 readonly Statement Increment;
421 public readonly Statement Statement;
422 bool infinite, empty;
424 public For (Statement initStatement,
430 InitStatement = initStatement;
432 Increment = increment;
433 Statement = statement;
437 public override bool Resolve (EmitContext ec)
441 if (InitStatement != null){
442 if (!InitStatement.Resolve (ec))
447 Test = Expression.ResolveBoolean (ec, Test, loc);
450 else if (Test is BoolConstant){
451 BoolConstant bc = (BoolConstant) Test;
453 if (bc.Value == false){
454 if (!Statement.ResolveUnreachable (ec, true))
456 if ((Increment != null) &&
457 !Increment.ResolveUnreachable (ec, false))
467 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
469 ec.CurrentBranching.CreateSibling ();
471 bool was_unreachable = ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable;
473 ec.StartFlowBranching (FlowBranching.BranchingType.Embedded, loc);
474 if (!Statement.Resolve (ec))
476 ec.EndFlowBranching ();
478 if (Increment != null){
479 if (ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable) {
480 if (!Increment.ResolveUnreachable (ec, !was_unreachable))
483 if (!Increment.Resolve (ec))
488 // There's no direct control flow from the end of the embedded statement to the end of the loop
489 ec.CurrentBranching.CurrentUsageVector.Goto ();
491 ec.EndFlowBranching ();
496 protected override void DoEmit (EmitContext ec)
501 ILGenerator ig = ec.ig;
502 Label old_begin = ec.LoopBegin;
503 Label old_end = ec.LoopEnd;
504 Label loop = ig.DefineLabel ();
505 Label test = ig.DefineLabel ();
507 if (InitStatement != null && InitStatement != EmptyStatement.Value)
508 InitStatement.Emit (ec);
510 ec.LoopBegin = ig.DefineLabel ();
511 ec.LoopEnd = ig.DefineLabel ();
513 ig.Emit (OpCodes.Br, test);
517 ig.MarkLabel (ec.LoopBegin);
518 if (Increment != EmptyStatement.Value)
523 // If test is null, there is no test, and we are just
528 // The Resolve code already catches the case for
529 // Test == BoolConstant (false) so we know that
532 if (Test is BoolConstant)
533 ig.Emit (OpCodes.Br, loop);
535 Test.EmitBranchable (ec, loop, true);
538 ig.Emit (OpCodes.Br, loop);
539 ig.MarkLabel (ec.LoopEnd);
541 ec.LoopBegin = old_begin;
542 ec.LoopEnd = old_end;
546 public class StatementExpression : Statement {
547 ExpressionStatement expr;
549 public StatementExpression (ExpressionStatement expr)
555 public override bool Resolve (EmitContext ec)
558 expr = expr.ResolveStatement (ec);
562 protected override void DoEmit (EmitContext ec)
564 expr.EmitStatement (ec);
567 public override string ToString ()
569 return "StatementExpression (" + expr + ")";
574 /// Implements the return statement
576 public class Return : Statement {
577 public Expression Expr;
579 public Return (Expression expr, Location l)
587 public override bool Resolve (EmitContext ec)
589 AnonymousContainer am = ec.CurrentAnonymousMethod;
590 if ((am != null) && am.IsIterator && ec.InIterator) {
591 Report.Error (1622, loc, "Cannot return a value from iterators. Use the yield return " +
592 "statement to return a value, or yield break to end the iteration");
596 if (ec.ReturnType == null){
598 if (ec.CurrentAnonymousMethod != null){
599 Report.Error (1662, loc,
600 "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",
601 ec.CurrentAnonymousMethod.GetSignatureForError ());
603 Error (127, "A return keyword must not be followed by any expression when method returns void");
608 Error (126, "An object of a type convertible to `{0}' is required " +
609 "for the return statement",
610 TypeManager.CSharpName (ec.ReturnType));
614 Expr = Expr.Resolve (ec);
618 if (Expr.Type != ec.ReturnType) {
619 Expr = Convert.ImplicitConversionRequired (
620 ec, Expr, ec.ReturnType, loc);
626 int errors = Report.Errors;
627 in_exc = ec.CurrentBranching.AddReturnOrigin (ec.CurrentBranching.CurrentUsageVector, loc);
629 ec.NeedReturnLabel ();
630 ec.CurrentBranching.CurrentUsageVector.Return ();
631 return errors == Report.Errors;
634 protected override void DoEmit (EmitContext ec)
640 ec.ig.Emit (OpCodes.Stloc, ec.TemporaryReturn ());
644 ec.ig.Emit (OpCodes.Leave, ec.ReturnLabel);
646 ec.ig.Emit (OpCodes.Ret);
650 public class Goto : Statement {
652 LabeledStatement label;
654 public override bool Resolve (EmitContext ec)
656 label = ec.CurrentBranching.LookupLabel (target, loc);
660 // If this is a forward goto.
661 if (!label.IsDefined)
662 label.AddUsageVector (ec.CurrentBranching.CurrentUsageVector);
664 ec.CurrentBranching.CurrentUsageVector.Goto ();
669 public Goto (string label, Location l)
675 public string Target {
676 get { return target; }
679 protected override void DoEmit (EmitContext ec)
681 Label l = label.LabelTarget (ec);
682 ec.ig.Emit (OpCodes.Br, l);
686 public class LabeledStatement : Statement {
693 FlowBranching.UsageVector vectors;
695 public LabeledStatement (string name, Location l)
701 public Label LabelTarget (EmitContext ec)
706 label = ec.ig.DefineLabel ();
716 public bool IsDefined {
717 get { return defined; }
720 public bool HasBeenReferenced {
721 get { return referenced; }
724 public FlowBranching.UsageVector JumpOrigins {
725 get { return vectors; }
728 public void AddUsageVector (FlowBranching.UsageVector vector)
730 vector = vector.Clone ();
731 vector.Next = vectors;
735 public override bool Resolve (EmitContext ec)
737 ec.CurrentBranching.CurrentUsageVector.MergeOrigins (vectors);
739 // this flow-branching will be terminated when the surrounding block ends
740 ec.StartFlowBranching (this);
744 protected override void DoEmit (EmitContext ec)
746 if (ig != null && ig != ec.ig)
747 throw new InternalErrorException ("cannot happen");
749 ec.ig.MarkLabel (label);
752 public void AddReference ()
760 /// `goto default' statement
762 public class GotoDefault : Statement {
764 public GotoDefault (Location l)
769 public override bool Resolve (EmitContext ec)
771 ec.CurrentBranching.CurrentUsageVector.Goto ();
775 protected override void DoEmit (EmitContext ec)
777 if (ec.Switch == null){
778 Report.Error (153, loc, "A goto case is only valid inside a switch statement");
782 if (!ec.Switch.GotDefault){
783 Report.Error (159, loc, "No such label `default:' within the scope of the goto statement");
786 ec.ig.Emit (OpCodes.Br, ec.Switch.DefaultTarget);
791 /// `goto case' statement
793 public class GotoCase : Statement {
797 public GotoCase (Expression e, Location l)
803 public override bool Resolve (EmitContext ec)
805 if (ec.Switch == null){
806 Report.Error (153, loc, "A goto case is only valid inside a switch statement");
810 expr = expr.Resolve (ec);
814 Constant c = expr as Constant;
816 Error (150, "A constant value is expected");
820 c = c.ToType (ec.Switch.SwitchType, loc);
824 object val = c.GetValue ();
826 val = SwitchLabel.NullStringCase;
828 sl = (SwitchLabel) ec.Switch.Elements [val];
831 Report.Error (159, loc, "No such label `case {0}:' within the scope of the goto statement", c.GetValue () == null ? "null" : val.ToString ());
835 ec.CurrentBranching.CurrentUsageVector.Goto ();
839 protected override void DoEmit (EmitContext ec)
841 ec.ig.Emit (OpCodes.Br, sl.GetILLabelCode (ec));
845 public class Throw : Statement {
848 public Throw (Expression expr, Location l)
854 public override bool Resolve (EmitContext ec)
856 ec.CurrentBranching.CurrentUsageVector.Throw ();
859 expr = expr.Resolve (ec);
863 ExprClass eclass = expr.eclass;
865 if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
866 eclass == ExprClass.Value || eclass == ExprClass.IndexerAccess)) {
867 expr.Error_UnexpectedKind (ec.DeclContainer, "value, variable, property or indexer access ", loc);
873 if ((t != TypeManager.exception_type) &&
874 !t.IsSubclassOf (TypeManager.exception_type) &&
875 !(expr is NullLiteral)) {
877 "The type caught or thrown must be derived " +
878 "from System.Exception");
885 Error (156, "A throw statement with no arguments is not allowed outside of a catch clause");
890 Error (724, "A throw statement with no arguments is not allowed inside of a finally clause nested inside of the innermost catch clause");
896 protected override void DoEmit (EmitContext ec)
899 ec.ig.Emit (OpCodes.Rethrow);
903 ec.ig.Emit (OpCodes.Throw);
908 public class Break : Statement {
910 public Break (Location l)
917 public override bool Resolve (EmitContext ec)
919 int errors = Report.Errors;
920 crossing_exc = ec.CurrentBranching.AddBreakOrigin (ec.CurrentBranching.CurrentUsageVector, loc);
921 ec.CurrentBranching.CurrentUsageVector.Goto ();
922 return errors == Report.Errors;
925 protected override void DoEmit (EmitContext ec)
927 ec.ig.Emit (crossing_exc ? OpCodes.Leave : OpCodes.Br, ec.LoopEnd);
931 public class Continue : Statement {
933 public Continue (Location l)
940 public override bool Resolve (EmitContext ec)
942 int errors = Report.Errors;
943 crossing_exc = ec.CurrentBranching.AddContinueOrigin (ec.CurrentBranching.CurrentUsageVector, loc);
944 ec.CurrentBranching.CurrentUsageVector.Goto ();
945 return errors == Report.Errors;
948 protected override void DoEmit (EmitContext ec)
950 ec.ig.Emit (crossing_exc ? OpCodes.Leave : OpCodes.Br, ec.LoopBegin);
955 // The information about a user-perceived local variable
957 public class LocalInfo {
958 public Expression Type;
961 // Most of the time a variable will be stored in a LocalBuilder
963 // But sometimes, it will be stored in a field (variables that have been
964 // hoisted by iterators or by anonymous methods). The context of the field will
965 // be stored in the EmitContext
968 public LocalBuilder LocalBuilder;
969 public FieldBuilder FieldBuilder;
971 public Type VariableType;
972 public readonly string Name;
973 public readonly Location Location;
974 public readonly Block Block;
976 public VariableInfo VariableInfo;
986 CompilerGenerated = 64,
990 public enum ReadOnlyContext: byte {
997 ReadOnlyContext ro_context;
999 public LocalInfo (Expression type, string name, Block block, Location l)
1007 public LocalInfo (DeclSpace ds, Block block, Location l)
1009 VariableType = ds.TypeBuilder;
1014 public void DeclareLocal (ILGenerator ig)
1018 // This is needed to compile on both .NET 1.x and .NET 2.x
1019 // the later introduced `DeclareLocal (Type t, bool pinned)'
1021 LocalBuilder = TypeManager.DeclareLocalPinned (ig, VariableType);
1024 if (!IsThis && !IsConstant)
1025 LocalBuilder = ig.DeclareLocal (VariableType);
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.Type;
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 IsConstant {
1086 return (flags & Flags.IsConstant) != 0;
1089 flags |= Flags.IsConstant;
1093 public bool AddressTaken {
1095 return (flags & Flags.AddressTaken) != 0;
1099 flags |= Flags.AddressTaken;
1103 public bool CompilerGenerated {
1105 return (flags & Flags.CompilerGenerated) != 0;
1109 flags |= Flags.CompilerGenerated;
1113 public override string ToString ()
1115 return String.Format ("LocalInfo ({0},{1},{2},{3})",
1116 Name, Type, VariableInfo, Location);
1121 return (flags & Flags.Used) != 0;
1124 flags = value ? (flags | Flags.Used) : (unchecked (flags & ~Flags.Used));
1128 public bool ReadOnly {
1130 return (flags & Flags.ReadOnly) != 0;
1134 public void SetReadOnlyContext (ReadOnlyContext context)
1136 flags |= Flags.ReadOnly;
1137 ro_context = context;
1140 public string GetReadOnlyContext ()
1143 throw new InternalErrorException ("Variable is not readonly");
1145 switch (ro_context) {
1146 case ReadOnlyContext.Fixed:
1147 return "fixed variable";
1148 case ReadOnlyContext.Foreach:
1149 return "foreach iteration variable";
1150 case ReadOnlyContext.Using:
1151 return "using variable";
1153 throw new NotImplementedException ();
1157 // Whether the variable is pinned, if Pinned the variable has been
1158 // allocated in a pinned slot with DeclareLocal.
1160 public bool Pinned {
1162 return (flags & Flags.Pinned) != 0;
1165 flags = value ? (flags | Flags.Pinned) : (flags & ~Flags.Pinned);
1169 public bool IsThis {
1171 return (flags & Flags.IsThis) != 0;
1174 flags = value ? (flags | Flags.IsThis) : (flags & ~Flags.IsThis);
1180 /// Block represents a C# block.
1184 /// This class is used in a number of places: either to represent
1185 /// explicit blocks that the programmer places or implicit blocks.
1187 /// Implicit blocks are used as labels or to introduce variable
1190 /// Top-level blocks derive from Block, and they are called ToplevelBlock
1191 /// they contain extra information that is not necessary on normal blocks.
1193 public class Block : Statement {
1194 public Block Parent;
1195 public readonly Location StartLocation;
1196 public Location EndLocation = Location.Null;
1198 public readonly ToplevelBlock Toplevel;
1201 public enum Flags : ushort {
1205 VariablesInitialized = 8,
1210 HasVarargs = 256 // Used in ToplevelBlock
1212 protected Flags flags;
1214 public bool Implicit {
1215 get { return (flags & Flags.Implicit) != 0; }
1218 public bool Unchecked {
1219 get { return (flags & Flags.Unchecked) != 0; }
1220 set { flags |= Flags.Unchecked; }
1223 public bool Unsafe {
1224 get { return (flags & Flags.Unsafe) != 0; }
1225 set { flags |= Flags.Unsafe; }
1229 // The statements in this block
1231 ArrayList statements;
1235 // An array of Blocks. We keep track of children just
1236 // to generate the local variable declarations.
1238 // Statements and child statements are handled through the
1244 // Labels. (label, block) pairs.
1249 // Keeps track of (name, type) pairs
1251 IDictionary variables;
1254 // Keeps track of constants
1255 Hashtable constants;
1258 // Temporary variables.
1260 ArrayList temporary_variables;
1263 // If this is a switch section, the enclosing switch block.
1267 protected static int id;
1271 public Block (Block parent)
1272 : this (parent, (Flags) 0, Location.Null, Location.Null)
1275 public Block (Block parent, Flags flags)
1276 : this (parent, flags, Location.Null, Location.Null)
1279 public Block (Block parent, Location start, Location end)
1280 : this (parent, (Flags) 0, start, end)
1283 public Block (Block parent, Flags flags, Location start, Location end)
1286 parent.AddChild (this);
1288 this.Parent = parent;
1290 this.StartLocation = start;
1291 this.EndLocation = end;
1294 statements = new ArrayList ();
1296 if ((flags & Flags.IsToplevel) != 0)
1297 Toplevel = (ToplevelBlock) this;
1299 Toplevel = parent.Toplevel;
1301 if (parent != null && Implicit) {
1302 if (parent.known_variables == null)
1303 parent.known_variables = new Hashtable ();
1304 // share with parent
1305 known_variables = parent.known_variables;
1309 public Block CreateSwitchBlock (Location start)
1311 Block new_block = new Block (this, start, start);
1312 new_block.switch_block = this;
1317 get { return this_id; }
1320 protected IDictionary Variables {
1322 if (variables == null)
1323 variables = new ListDictionary ();
1328 void AddChild (Block b)
1330 if (children == null)
1331 children = new ArrayList ();
1336 public void SetEndLocation (Location loc)
1342 /// Adds a label to the current block.
1346 /// false if the name already exists in this block. true
1350 public bool AddLabel (LabeledStatement target)
1352 if (switch_block != null)
1353 return switch_block.AddLabel (target);
1355 string name = target.Name;
1358 while (cur != null) {
1359 if (cur.DoLookupLabel (name) != null) {
1360 Report.Error (140, target.loc, "The label `{0}' is a duplicate", name);
1370 while (cur != null) {
1371 if (cur.DoLookupLabel (name) != null) {
1374 "The label `{0}' shadows another label by the same name in a contained scope.",
1379 if (children != null) {
1380 foreach (Block b in children) {
1381 LabeledStatement s = b.DoLookupLabel (name);
1387 "The label `{0}' shadows another label by the same name in a contained scope.",
1398 labels = new Hashtable ();
1400 labels.Add (name, target);
1404 public LabeledStatement LookupLabel (string name)
1406 LabeledStatement s = DoLookupLabel (name);
1410 if (children == null)
1413 foreach (Block child in children) {
1414 if (!child.Implicit)
1417 s = child.LookupLabel (name);
1425 LabeledStatement DoLookupLabel (string name)
1427 if (switch_block != null)
1428 return switch_block.LookupLabel (name);
1431 if (labels.Contains (name))
1432 return ((LabeledStatement) labels [name]);
1437 Hashtable known_variables;
1440 // Marks a variable with name @name as being used in this or a child block.
1441 // If a variable name has been used in a child block, it's illegal to
1442 // declare a variable with the same name in the current block.
1444 void AddKnownVariable (string name, LocalInfo info)
1446 if (known_variables == null)
1447 known_variables = new Hashtable ();
1449 known_variables [name] = info;
1452 LocalInfo GetKnownVariableInfo (string name)
1454 if (known_variables == null)
1456 return (LocalInfo) known_variables [name];
1459 public bool CheckInvariantMeaningInBlock (string name, Expression e, Location loc)
1462 LocalInfo kvi = b.GetKnownVariableInfo (name);
1463 while (kvi == null) {
1469 kvi = b.GetKnownVariableInfo (name);
1475 // Is kvi.Block nested inside 'b'
1476 if (b.known_variables != kvi.Block.known_variables) {
1478 // If a variable by the same name it defined in a nested block of this
1479 // block, we violate the invariant meaning in a block.
1482 Report.SymbolRelatedToPreviousError (kvi.Location, name);
1483 Report.Error (135, loc, "`{0}' conflicts with a declaration in a child block", name);
1488 // It's ok if the definition is in a nested subblock of b, but not
1489 // nested inside this block -- a definition in a sibling block
1490 // should not affect us.
1496 // Block 'b' and kvi.Block are the same textual block.
1497 // However, different variables are extant.
1499 // Check if the variable is in scope in both blocks. We use
1500 // an indirect check that depends on AddVariable doing its
1501 // part in maintaining the invariant-meaning-in-block property.
1503 if (e is LocalVariableReference || (e is Constant && b.GetLocalInfo (name) != null))
1507 // Even though we detected the error when the name is used, we
1508 // treat it as if the variable declaration was in error.
1510 Report.SymbolRelatedToPreviousError (loc, name);
1511 Error_AlreadyDeclared (kvi.Location, name, "parent or current");
1515 public LocalInfo AddVariable (Expression type, string name, Location l)
1517 LocalInfo vi = GetLocalInfo (name);
1519 Report.SymbolRelatedToPreviousError (vi.Location, name);
1520 if (known_variables == vi.Block.known_variables)
1521 Report.Error (128, l,
1522 "A local variable named `{0}' is already defined in this scope", name);
1524 Error_AlreadyDeclared (l, name, "parent");
1528 vi = GetKnownVariableInfo (name);
1530 Report.SymbolRelatedToPreviousError (vi.Location, name);
1531 Error_AlreadyDeclared (l, name, "child");
1536 Parameter p = Toplevel.Parameters.GetParameterByName (name, out idx);
1538 Report.SymbolRelatedToPreviousError (p.Location, name);
1539 Error_AlreadyDeclared (l, name, "method argument");
1543 vi = new LocalInfo (type, name, this, l);
1545 Variables.Add (name, vi);
1547 for (Block b = this; b != null; b = b.Parent)
1548 b.AddKnownVariable (name, vi);
1550 if ((flags & Flags.VariablesInitialized) != 0)
1551 throw new Exception ();
1556 void Error_AlreadyDeclared (Location loc, string var, string reason)
1558 Report.Error (136, loc, "A local variable named `{0}' cannot be declared in this scope because it would give a different meaning to `{0}', " +
1559 "which is already used in a `{1}' scope", var, reason);
1562 public bool AddConstant (Expression type, string name, Expression value, Location l)
1564 if (AddVariable (type, name, l) == null)
1567 if (constants == null)
1568 constants = new Hashtable ();
1570 constants.Add (name, value);
1572 // A block is considered used if we perform an initialization in a local declaration, even if it is constant.
1577 static int next_temp_id = 0;
1579 public LocalInfo AddTemporaryVariable (TypeExpr te, Location loc)
1581 if (temporary_variables == null)
1582 temporary_variables = new ArrayList ();
1584 int id = ++next_temp_id;
1585 string name = "$s_" + id.ToString ();
1587 LocalInfo li = new LocalInfo (te, name, this, loc);
1588 li.CompilerGenerated = true;
1589 temporary_variables.Add (li);
1593 public LocalInfo GetLocalInfo (string name)
1595 for (Block b = this; b != null; b = b.Parent) {
1596 if (b.variables != null) {
1597 LocalInfo ret = b.variables [name] as LocalInfo;
1605 public Expression GetVariableType (string name)
1607 LocalInfo vi = GetLocalInfo (name);
1608 return vi == null ? null : vi.Type;
1611 public Expression GetConstantExpression (string name)
1613 for (Block b = this; b != null; b = b.Parent) {
1614 if (b.constants != null) {
1615 Expression ret = b.constants [name] as Expression;
1623 public void AddStatement (Statement s)
1626 flags |= Flags.BlockUsed;
1630 get { return (flags & Flags.BlockUsed) != 0; }
1635 flags |= Flags.BlockUsed;
1638 public bool HasRet {
1639 get { return (flags & Flags.HasRet) != 0; }
1642 public bool IsDestructor {
1643 get { return (flags & Flags.IsDestructor) != 0; }
1646 public void SetDestructor ()
1648 flags |= Flags.IsDestructor;
1651 VariableMap param_map, local_map;
1653 public VariableMap ParameterMap {
1655 if ((flags & Flags.VariablesInitialized) == 0)
1656 throw new Exception ("Variables have not been initialized yet");
1662 public VariableMap LocalMap {
1664 if ((flags & Flags.VariablesInitialized) == 0)
1665 throw new Exception ("Variables have not been initialized yet");
1672 /// Emits the variable declarations and labels.
1675 /// tc: is our typecontainer (to resolve type references)
1676 /// ig: is the code generator:
1678 public void ResolveMeta (ToplevelBlock toplevel, EmitContext ec, Parameters ip)
1680 bool old_unsafe = ec.InUnsafe;
1682 // If some parent block was unsafe, we remain unsafe even if this block
1683 // isn't explicitly marked as such.
1684 ec.InUnsafe |= Unsafe;
1687 // Compute the VariableMap's.
1689 // Unfortunately, we don't know the type when adding variables with
1690 // AddVariable(), so we need to compute this info here.
1694 if (variables != null) {
1695 foreach (LocalInfo li in variables.Values)
1698 locals = new LocalInfo [variables.Count];
1699 variables.Values.CopyTo (locals, 0);
1701 locals = new LocalInfo [0];
1704 local_map = new VariableMap (Parent.LocalMap, locals);
1706 local_map = new VariableMap (locals);
1708 param_map = new VariableMap (ip);
1709 flags |= Flags.VariablesInitialized;
1711 bool old_check_state = ec.ConstantCheckState;
1712 ec.ConstantCheckState = (flags & Flags.Unchecked) == 0;
1715 // Process this block variables
1717 if (variables != null){
1718 foreach (DictionaryEntry de in variables){
1719 string name = (string) de.Key;
1720 LocalInfo vi = (LocalInfo) de.Value;
1722 if (vi.VariableType == null)
1725 Type variable_type = vi.VariableType;
1727 if (variable_type.IsPointer){
1729 // Am not really convinced that this test is required (Microsoft does it)
1730 // but the fact is that you would not be able to use the pointer variable
1733 if (!TypeManager.VerifyUnManaged (TypeManager.GetElementType (variable_type),
1738 if (constants == null)
1741 Expression cv = (Expression) constants [name];
1745 // Don't let 'const int Foo = Foo;' succeed.
1746 // Removing the name from 'constants' ensures that we get a LocalVariableReference below,
1747 // which in turn causes the 'must be constant' error to be triggered.
1748 constants.Remove (name);
1750 ec.CurrentBlock = this;
1751 Expression e = cv.Resolve (ec);
1755 Constant ce = e as Constant;
1757 Const.Error_ExpressionMustBeConstant (variable_type, vi.Location, name);
1761 e = ce.ToType (variable_type, vi.Location);
1765 if (!variable_type.IsValueType && variable_type != TypeManager.string_type && !ce.IsDefaultValue) {
1766 Const.Error_ConstantCanBeInitializedWithNullOnly (vi.Location, vi.Name);
1770 constants.Add (name, e);
1771 vi.IsConstant = true;
1774 ec.ConstantCheckState = old_check_state;
1777 // Now, handle the children
1779 if (children != null){
1780 foreach (Block b in children)
1781 b.ResolveMeta (toplevel, ec, ip);
1783 ec.InUnsafe = old_unsafe;
1787 // Emits the local variable declarations for a block
1789 public void EmitMeta (EmitContext ec)
1791 ILGenerator ig = ec.ig;
1793 if (variables != null){
1794 bool have_captured_vars = ec.HaveCapturedVariables ();
1796 foreach (DictionaryEntry de in variables){
1797 LocalInfo vi = (LocalInfo) de.Value;
1799 if (have_captured_vars && ec.IsCaptured (vi))
1802 vi.DeclareLocal (ig);
1806 if (temporary_variables != null) {
1807 AnonymousContainer am = ec.CurrentAnonymousMethod;
1808 TypeBuilder scope = null;
1809 if ((am != null) && am.IsIterator) {
1810 scope = am.Scope.ScopeTypeBuilder;
1812 throw new InternalErrorException ();
1814 foreach (LocalInfo vi in temporary_variables) {
1815 if (scope != null) {
1816 if (vi.FieldBuilder == null)
1817 vi.FieldBuilder = scope.DefineField (
1818 vi.Name, vi.VariableType, FieldAttributes.Assembly);
1820 vi.LocalBuilder = ig.DeclareLocal (vi.VariableType);
1824 if (children != null){
1825 foreach (Block b in children)
1830 void UsageWarning (FlowBranching.UsageVector vector)
1834 if ((variables != null) && (RootContext.WarningLevel >= 3)) {
1835 foreach (DictionaryEntry de in variables){
1836 LocalInfo vi = (LocalInfo) de.Value;
1841 name = (string) de.Key;
1843 // vi.VariableInfo can be null for 'catch' variables
1844 if (vi.VariableInfo != null && vector.IsAssigned (vi.VariableInfo, true)){
1845 Report.Warning (219, 3, vi.Location, "The variable `{0}' is assigned but its value is never used", name);
1847 Report.Warning (168, 3, vi.Location, "The variable `{0}' is declared but never used", name);
1853 bool unreachable_shown;
1856 private void CheckPossibleMistakenEmptyStatement (Statement s)
1860 // Some statements are wrapped by a Block. Since
1861 // others' internal could be changed, here I treat
1862 // them as possibly wrapped by Block equally.
1863 Block b = s as Block;
1864 if (b != null && b.statements.Count == 1)
1865 s = (Statement) b.statements [0];
1868 body = ((Lock) s).Statement;
1870 body = ((For) s).Statement;
1871 else if (s is Foreach)
1872 body = ((Foreach) s).Statement;
1873 else if (s is While)
1874 body = ((While) s).Statement;
1875 else if (s is Using)
1876 body = ((Using) s).Statement;
1877 else if (s is Fixed)
1878 body = ((Fixed) s).Statement;
1882 if (body == null || body is EmptyStatement)
1883 Report.Warning (642, 3, s.loc, "Possible mistaken empty statement");
1886 public override bool Resolve (EmitContext ec)
1888 Block prev_block = ec.CurrentBlock;
1891 int errors = Report.Errors;
1893 ec.CurrentBlock = this;
1894 ec.StartFlowBranching (this);
1896 Report.Debug (4, "RESOLVE BLOCK", StartLocation, ec.CurrentBranching);
1898 int statement_count = statements.Count;
1899 for (int ix = 0; ix < statement_count; ix++){
1900 Statement s = (Statement) statements [ix];
1901 // Check possible empty statement (CS0642)
1902 if (RootContext.WarningLevel >= 3 &&
1903 ix + 1 < statement_count &&
1904 statements [ix + 1] is Block)
1905 CheckPossibleMistakenEmptyStatement (s);
1908 // Warn if we detect unreachable code.
1911 if (s is EmptyStatement)
1915 ((Block) s).unreachable = true;
1917 if (!unreachable_shown) {
1918 Report.Warning (162, 2, s.loc, "Unreachable code detected");
1919 unreachable_shown = true;
1924 // Note that we're not using ResolveUnreachable() for unreachable
1925 // statements here. ResolveUnreachable() creates a temporary
1926 // flow branching and kills it afterwards. This leads to problems
1927 // if you have two unreachable statements where the first one
1928 // assigns a variable and the second one tries to access it.
1931 if (!s.Resolve (ec)) {
1933 statements [ix] = EmptyStatement.Value;
1937 if (unreachable && !(s is LabeledStatement) && !(s is Block))
1938 statements [ix] = EmptyStatement.Value;
1940 num_statements = ix + 1;
1941 if (s is LabeledStatement)
1942 unreachable = false;
1944 unreachable = ec.CurrentBranching.CurrentUsageVector.Reachability.IsUnreachable;
1947 Report.Debug (4, "RESOLVE BLOCK DONE", StartLocation,
1948 ec.CurrentBranching, statement_count, num_statements);
1950 while (ec.CurrentBranching is FlowBranchingLabeled)
1951 ec.EndFlowBranching ();
1953 FlowBranching.UsageVector vector = ec.DoEndFlowBranching ();
1955 ec.CurrentBlock = prev_block;
1957 // If we're a non-static `struct' constructor which doesn't have an
1958 // initializer, then we must initialize all of the struct's fields.
1959 if ((flags & Flags.IsToplevel) != 0 &&
1960 !Toplevel.IsThisAssigned (ec) &&
1961 !vector.Reachability.AlwaysThrows)
1964 if ((labels != null) && (RootContext.WarningLevel >= 2)) {
1965 foreach (LabeledStatement label in labels.Values)
1966 if (!label.HasBeenReferenced)
1967 Report.Warning (164, 2, label.loc,
1968 "This label has not been referenced");
1971 Report.Debug (4, "RESOLVE BLOCK DONE #2", StartLocation, vector);
1973 if (vector.Reachability.IsUnreachable)
1974 flags |= Flags.HasRet;
1976 if (ok && (errors == Report.Errors)) {
1977 if (RootContext.WarningLevel >= 3)
1978 UsageWarning (vector);
1984 public override bool ResolveUnreachable (EmitContext ec, bool warn)
1986 unreachable_shown = true;
1990 Report.Warning (162, 2, loc, "Unreachable code detected");
1992 ec.StartFlowBranching (FlowBranching.BranchingType.Block, loc);
1993 bool ok = Resolve (ec);
1994 ec.KillFlowBranching ();
1999 protected override void DoEmit (EmitContext ec)
2001 for (int ix = 0; ix < num_statements; ix++){
2002 Statement s = (Statement) statements [ix];
2004 // Check whether we are the last statement in a
2007 if (((Parent == null) || Implicit) && (ix+1 == num_statements) && !(s is Block))
2008 ec.IsLastStatement = true;
2010 ec.IsLastStatement = false;
2016 public override void Emit (EmitContext ec)
2018 Block prev_block = ec.CurrentBlock;
2020 ec.CurrentBlock = this;
2022 bool emit_debug_info = (CodeGen.SymbolWriter != null);
2023 bool is_lexical_block = !Implicit && (Parent != null);
2025 if (emit_debug_info) {
2026 if (is_lexical_block)
2029 if (variables != null) {
2030 foreach (DictionaryEntry de in variables) {
2031 string name = (string) de.Key;
2032 LocalInfo vi = (LocalInfo) de.Value;
2034 if (vi.LocalBuilder == null)
2037 ec.DefineLocalVariable (name, vi.LocalBuilder);
2041 ec.Mark (StartLocation, true);
2042 ec.EmitScopeInitFromBlock (this);
2044 ec.Mark (EndLocation, true);
2046 if (emit_debug_info && is_lexical_block)
2049 ec.CurrentBlock = prev_block;
2053 // Returns true if we ar ea child of `b'.
2055 public bool IsChildOf (Block b)
2057 Block current = this;
2060 if (current.Parent == b)
2062 current = current.Parent;
2063 } while (current != null);
2067 public override string ToString ()
2069 return String.Format ("{0} ({1}:{2})", GetType (),ID, StartLocation);
2074 // A toplevel block contains extra information, the split is done
2075 // only to separate information that would otherwise bloat the more
2076 // lightweight Block.
2078 // In particular, this was introduced when the support for Anonymous
2079 // Methods was implemented.
2081 public class ToplevelBlock : Block {
2083 // Pointer to the host of this anonymous method, or null
2084 // if we are the topmost block
2086 ToplevelBlock container;
2087 CaptureContext capture_context;
2088 FlowBranching top_level_branching;
2090 Hashtable capture_contexts;
2093 public bool HasVarargs {
2094 get { return (flags & Flags.HasVarargs) != 0; }
2095 set { flags |= Flags.HasVarargs; }
2099 // The parameters for the block.
2101 public readonly Parameters Parameters;
2103 public void RegisterCaptureContext (CaptureContext cc)
2105 if (capture_contexts == null)
2106 capture_contexts = new Hashtable ();
2107 capture_contexts [cc] = cc;
2110 public void CompleteContexts ()
2112 if (capture_contexts == null)
2115 foreach (CaptureContext cc in capture_contexts.Keys){
2120 public CaptureContext ToplevelBlockCaptureContext {
2121 get { return capture_context; }
2124 public ToplevelBlock Container {
2125 get { return container; }
2128 protected void AddChild (ToplevelBlock block)
2130 if (children == null)
2131 children = new ArrayList ();
2133 children.Add (block);
2137 // Parent is only used by anonymous blocks to link back to their
2140 public ToplevelBlock (ToplevelBlock container, Parameters parameters, Location start) :
2141 this (container, (Flags) 0, parameters, start)
2145 public ToplevelBlock (Parameters parameters, Location start) :
2146 this (null, (Flags) 0, parameters, start)
2150 public ToplevelBlock (Flags flags, Parameters parameters, Location start) :
2151 this (null, flags, parameters, start)
2155 public ToplevelBlock (ToplevelBlock container, Flags flags, Parameters parameters, Location start) :
2156 base (null, flags | Flags.IsToplevel, start, Location.Null)
2158 Parameters = parameters == null ? Parameters.EmptyReadOnlyParameters : parameters;
2159 this.container = container;
2161 if (container != null)
2162 container.AddChild (this);
2165 public ToplevelBlock (Location loc) : this (null, (Flags) 0, null, loc)
2169 public void SetHaveAnonymousMethods (Location loc, AnonymousContainer host)
2171 if (capture_context == null)
2172 capture_context = new CaptureContext (this, loc, host);
2175 public CaptureContext CaptureContext {
2176 get { return capture_context; }
2179 public FlowBranching TopLevelBranching {
2180 get { return top_level_branching; }
2184 // This is used if anonymous methods are used inside an iterator
2185 // (see 2test-22.cs for an example).
2187 // The AnonymousMethod is created while parsing - at a time when we don't
2188 // know yet that we're inside an iterator, so it's `Container' is initially
2189 // null. Later on, when resolving the iterator, we need to move the
2190 // anonymous method into that iterator.
2192 public void ReParent (ToplevelBlock new_parent, AnonymousContainer new_host)
2194 foreach (ToplevelBlock block in children) {
2195 if (block.CaptureContext == null)
2198 block.container = new_parent;
2199 block.CaptureContext.ReParent (new_parent, new_host);
2204 // Returns a `ParameterReference' for the given name, or null if there
2205 // is no such parameter
2207 public ParameterReference GetParameterReference (string name, Location loc)
2212 for (ToplevelBlock t = this; t != null; t = t.Container) {
2213 Parameters pars = t.Parameters;
2214 par = pars.GetParameterByName (name, out idx);
2216 return new ParameterReference (par, this, idx, loc);
2222 // Whether the parameter named `name' is local to this block,
2223 // or false, if the parameter belongs to an encompassing block.
2225 public bool IsLocalParameter (string name)
2227 return Parameters.GetParameterByName (name) != null;
2231 // Whether the `name' is a parameter reference
2233 public bool IsParameterReference (string name)
2235 for (ToplevelBlock t = this; t != null; t = t.Container) {
2236 if (t.IsLocalParameter (name))
2242 LocalInfo this_variable = null;
2245 // Returns the "this" instance variable of this block.
2246 // See AddThisVariable() for more information.
2248 public LocalInfo ThisVariable {
2249 get { return this_variable; }
2254 // This is used by non-static `struct' constructors which do not have an
2255 // initializer - in this case, the constructor must initialize all of the
2256 // struct's fields. To do this, we add a "this" variable and use the flow
2257 // analysis code to ensure that it's been fully initialized before control
2258 // leaves the constructor.
2260 public LocalInfo AddThisVariable (DeclSpace ds, Location l)
2262 if (this_variable == null) {
2263 this_variable = new LocalInfo (ds, this, l);
2264 this_variable.Used = true;
2265 this_variable.IsThis = true;
2267 Variables.Add ("this", this_variable);
2270 return this_variable;
2273 public bool IsThisAssigned (EmitContext ec)
2275 return this_variable == null || this_variable.IsThisAssigned (ec, loc);
2278 public bool ResolveMeta (EmitContext ec, Parameters ip)
2280 int errors = Report.Errors;
2282 if (top_level_branching != null)
2285 ResolveMeta (this, ec, ip);
2287 top_level_branching = ec.StartFlowBranching (this);
2289 return Report.Errors == errors;
2293 public class SwitchLabel {
2300 Label il_label_code;
2301 bool il_label_code_set;
2303 public static readonly object NullStringCase = new object ();
2306 // if expr == null, then it is the default case.
2308 public SwitchLabel (Expression expr, Location l)
2314 public Expression Label {
2320 public object Converted {
2326 public Label GetILLabel (EmitContext ec)
2329 il_label = ec.ig.DefineLabel ();
2330 il_label_set = true;
2335 public Label GetILLabelCode (EmitContext ec)
2337 if (!il_label_code_set){
2338 il_label_code = ec.ig.DefineLabel ();
2339 il_label_code_set = true;
2341 return il_label_code;
2345 // Resolves the expression, reduces it to a literal if possible
2346 // and then converts it to the requested type.
2348 public bool ResolveAndReduce (EmitContext ec, Type required_type)
2350 Expression e = label.Resolve (ec);
2355 Constant c = e as Constant;
2357 Report.Error (150, loc, "A constant value is expected");
2361 if (required_type == TypeManager.string_type && c.GetValue () == null) {
2362 converted = NullStringCase;
2366 c = c.ToType (required_type, loc);
2370 converted = c.GetValue ();
2374 public void Erorr_AlreadyOccurs ()
2377 if (converted == null)
2379 else if (converted == NullStringCase)
2382 label = converted.ToString ();
2384 Report.Error (152, loc, "The label `case {0}:' already occurs in this switch statement", label);
2388 public class SwitchSection {
2389 // An array of SwitchLabels.
2390 public readonly ArrayList Labels;
2391 public readonly Block Block;
2393 public SwitchSection (ArrayList labels, Block block)
2400 public class Switch : Statement {
2401 public readonly ArrayList Sections;
2402 public Expression Expr;
2405 /// Maps constants whose type type SwitchType to their SwitchLabels.
2407 public IDictionary Elements;
2410 /// The governing switch type
2412 public Type SwitchType;
2417 Label default_target;
2418 Expression new_expr;
2420 SwitchSection constant_section;
2421 SwitchSection default_section;
2424 // The types allowed to be implicitly cast from
2425 // on the governing type
2427 static Type [] allowed_types;
2429 public Switch (Expression e, ArrayList sects, Location l)
2436 public bool GotDefault {
2438 return default_section != null;
2442 public Label DefaultTarget {
2444 return default_target;
2449 // Determines the governing type for a switch. The returned
2450 // expression might be the expression from the switch, or an
2451 // expression that includes any potential conversions to the
2452 // integral types or to string.
2454 Expression SwitchGoverningType (EmitContext ec, Type t)
2456 if (t == TypeManager.byte_type ||
2457 t == TypeManager.sbyte_type ||
2458 t == TypeManager.ushort_type ||
2459 t == TypeManager.short_type ||
2460 t == TypeManager.uint32_type ||
2461 t == TypeManager.int32_type ||
2462 t == TypeManager.uint64_type ||
2463 t == TypeManager.int64_type ||
2464 t == TypeManager.char_type ||
2465 t == TypeManager.string_type ||
2466 t == TypeManager.bool_type ||
2467 t.IsSubclassOf (TypeManager.enum_type))
2470 if (allowed_types == null){
2471 allowed_types = new Type [] {
2472 TypeManager.sbyte_type,
2473 TypeManager.byte_type,
2474 TypeManager.short_type,
2475 TypeManager.ushort_type,
2476 TypeManager.int32_type,
2477 TypeManager.uint32_type,
2478 TypeManager.int64_type,
2479 TypeManager.uint64_type,
2480 TypeManager.char_type,
2481 TypeManager.string_type,
2482 TypeManager.bool_type
2487 // Try to find a *user* defined implicit conversion.
2489 // If there is no implicit conversion, or if there are multiple
2490 // conversions, we have to report an error
2492 Expression converted = null;
2493 foreach (Type tt in allowed_types){
2496 e = Convert.ImplicitUserConversion (ec, Expr, tt, loc);
2501 // Ignore over-worked ImplicitUserConversions that do
2502 // an implicit conversion in addition to the user conversion.
2504 if (!(e is UserCast))
2507 if (converted != null){
2508 Report.ExtraInformation (
2510 String.Format ("reason: more than one conversion to an integral type exist for type {0}",
2511 TypeManager.CSharpName (Expr.Type)));
2521 // Performs the basic sanity checks on the switch statement
2522 // (looks for duplicate keys and non-constant expressions).
2524 // It also returns a hashtable with the keys that we will later
2525 // use to compute the switch tables
2527 bool CheckSwitch (EmitContext ec)
2530 Elements = Sections.Count > 10 ?
2531 (IDictionary)new Hashtable () :
2532 (IDictionary)new ListDictionary ();
2534 foreach (SwitchSection ss in Sections){
2535 foreach (SwitchLabel sl in ss.Labels){
2536 if (sl.Label == null){
2537 if (default_section != null){
2538 sl.Erorr_AlreadyOccurs ();
2541 default_section = ss;
2545 if (!sl.ResolveAndReduce (ec, SwitchType)){
2550 object key = sl.Converted;
2552 Elements.Add (key, sl);
2554 catch (ArgumentException) {
2555 sl.Erorr_AlreadyOccurs ();
2563 void EmitObjectInteger (ILGenerator ig, object k)
2566 IntConstant.EmitInt (ig, (int) k);
2567 else if (k is Constant) {
2568 EmitObjectInteger (ig, ((Constant) k).GetValue ());
2571 IntConstant.EmitInt (ig, unchecked ((int) (uint) k));
2574 if ((long) k >= int.MinValue && (long) k <= int.MaxValue)
2576 IntConstant.EmitInt (ig, (int) (long) k);
2577 ig.Emit (OpCodes.Conv_I8);
2580 LongConstant.EmitLong (ig, (long) k);
2582 else if (k is ulong)
2584 ulong ul = (ulong) k;
2587 IntConstant.EmitInt (ig, unchecked ((int) ul));
2588 ig.Emit (OpCodes.Conv_U8);
2592 LongConstant.EmitLong (ig, unchecked ((long) ul));
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.AlwaysReturns) {
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.Type;
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;
3560 public readonly Block VarBlock;
3562 Expression type_expr;
3565 public Catch (Expression type, string name, Block block, Block var_block, Location l)
3570 VarBlock = var_block;
3574 public Type CatchType {
3580 public bool IsGeneral {
3582 return type_expr == null;
3586 protected override void DoEmit(EmitContext ec)
3590 public override bool Resolve (EmitContext ec)
3592 bool was_catch = ec.InCatch;
3595 if (type_expr != null) {
3596 TypeExpr te = type_expr.ResolveAsTypeTerminal (ec, false);
3602 if (type != TypeManager.exception_type && !type.IsSubclassOf (TypeManager.exception_type)){
3603 Error (155, "The type caught or thrown must be derived from System.Exception");
3609 if (!Block.Resolve (ec))
3612 // Even though VarBlock surrounds 'Block' we resolve it later, so that we can correctly
3613 // emit the "unused variable" warnings.
3614 if (VarBlock != null)
3615 return VarBlock.Resolve (ec);
3620 ec.InCatch = was_catch;
3625 public class Try : ExceptionStatement {
3626 public readonly Block Fini, Block;
3627 public readonly ArrayList Specific;
3628 public readonly Catch General;
3630 bool need_exc_block;
3633 // specific, general and fini might all be null.
3635 public Try (Block block, ArrayList specific, Catch general, Block fini, Location l)
3637 if (specific == null && general == null){
3638 Console.WriteLine ("CIR.Try: Either specific or general have to be non-null");
3642 this.Specific = specific;
3643 this.General = general;
3648 public override bool Resolve (EmitContext ec)
3652 FlowBranchingException branching = ec.StartFlowBranching (this);
3654 Report.Debug (1, "START OF TRY BLOCK", Block.StartLocation);
3656 if (!Block.Resolve (ec))
3659 FlowBranching.UsageVector vector = ec.CurrentBranching.CurrentUsageVector;
3661 Report.Debug (1, "START OF CATCH BLOCKS", vector);
3663 Type[] prevCatches = new Type [Specific.Count];
3665 foreach (Catch c in Specific){
3666 ec.CurrentBranching.CreateSibling (
3667 c.Block, FlowBranching.SiblingType.Catch);
3669 Report.Debug (1, "STARTED SIBLING FOR CATCH", ec.CurrentBranching);
3671 if (c.Name != null) {
3672 LocalInfo vi = c.Block.GetLocalInfo (c.Name);
3674 throw new Exception ();
3676 vi.VariableInfo = null;
3679 if (!c.Resolve (ec))
3682 Type resolvedType = c.CatchType;
3683 for (int ii = 0; ii < last_index; ++ii) {
3684 if (resolvedType == prevCatches [ii] || resolvedType.IsSubclassOf (prevCatches [ii])) {
3685 Report.Error (160, c.loc, "A previous catch clause already catches all exceptions of this or a super type `{0}'", prevCatches [ii].FullName);
3690 prevCatches [last_index++] = resolvedType;
3691 need_exc_block = true;
3694 Report.Debug (1, "END OF CATCH BLOCKS", ec.CurrentBranching);
3696 if (General != null){
3697 if (CodeGen.Assembly.WrapNonExceptionThrows) {
3698 foreach (Catch c in Specific){
3699 if (c.CatchType == TypeManager.exception_type) {
3700 Report.Warning (1058, 1, c.loc, "A previous catch clause already catches all exceptions. All non-exceptions thrown will be wrapped in a `System.Runtime.CompilerServices.RuntimeWrappedException'");
3705 ec.CurrentBranching.CreateSibling (
3706 General.Block, FlowBranching.SiblingType.Catch);
3708 Report.Debug (1, "STARTED SIBLING FOR GENERAL", ec.CurrentBranching);
3710 if (!General.Resolve (ec))
3713 need_exc_block = true;
3716 Report.Debug (1, "END OF GENERAL CATCH BLOCKS", ec.CurrentBranching);
3720 ec.CurrentBranching.CreateSibling (
3721 Fini, FlowBranching.SiblingType.Finally);
3723 Report.Debug (1, "STARTED SIBLING FOR FINALLY", ec.CurrentBranching, vector);
3724 bool was_finally = ec.InFinally;
3725 ec.InFinally = true;
3726 if (!Fini.Resolve (ec))
3728 ec.InFinally = was_finally;
3731 need_exc_block = true;
3734 if (ec.InIterator) {
3735 ResolveFinally (branching);
3736 need_exc_block |= emit_finally;
3738 emit_finally = Fini != null;
3740 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
3742 FlowBranching.UsageVector f_vector = ec.CurrentBranching.CurrentUsageVector;
3744 Report.Debug (1, "END OF TRY", ec.CurrentBranching, reachability, vector, f_vector);
3746 if (!reachability.AlwaysReturns) {
3747 // Unfortunately, System.Reflection.Emit automatically emits
3748 // a leave to the end of the finally block. This is a problem
3749 // if `returns' is true since we may jump to a point after the
3750 // end of the method.
3751 // As a workaround, emit an explicit ret here.
3752 ec.NeedReturnLabel ();
3758 protected override void DoEmit (EmitContext ec)
3760 ILGenerator ig = ec.ig;
3763 ig.BeginExceptionBlock ();
3766 foreach (Catch c in Specific){
3769 ig.BeginCatchBlock (c.CatchType);
3771 if (c.VarBlock != null)
3772 ec.EmitScopeInitFromBlock (c.VarBlock);
3773 if (c.Name != null){
3774 vi = c.Block.GetLocalInfo (c.Name);
3776 throw new Exception ("Variable does not exist in this block");
3779 LocalBuilder e = ig.DeclareLocal (vi.VariableType);
3780 ig.Emit (OpCodes.Stloc, e);
3782 ec.EmitCapturedVariableInstance (vi);
3783 ig.Emit (OpCodes.Ldloc, e);
3784 ig.Emit (OpCodes.Stfld, vi.FieldBuilder);
3786 ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
3788 ig.Emit (OpCodes.Pop);
3793 if (General != null){
3794 ig.BeginCatchBlock (TypeManager.object_type);
3795 ig.Emit (OpCodes.Pop);
3796 General.Block.Emit (ec);
3801 ig.EndExceptionBlock ();
3804 public override void EmitFinally (EmitContext ec)
3810 public bool HasCatch
3813 return General != null || Specific.Count > 0;
3818 public class Using : ExceptionStatement {
3819 object expression_or_block;
3820 public Statement Statement;
3824 Expression [] resolved_vars;
3825 Expression [] converted_vars;
3826 ExpressionStatement [] assign;
3827 LocalBuilder local_copy;
3829 public Using (object expression_or_block, Statement stmt, Location l)
3831 this.expression_or_block = expression_or_block;
3837 // Resolves for the case of using using a local variable declaration.
3839 bool ResolveLocalVariableDecls (EmitContext ec)
3843 TypeExpr texpr = expr.ResolveAsTypeTerminal (ec, false);
3847 expr_type = texpr.Type;
3850 // The type must be an IDisposable or an implicit conversion
3853 converted_vars = new Expression [var_list.Count];
3854 resolved_vars = new Expression [var_list.Count];
3855 assign = new ExpressionStatement [var_list.Count];
3857 bool need_conv = !TypeManager.ImplementsInterface (
3858 expr_type, TypeManager.idisposable_type);
3860 foreach (DictionaryEntry e in var_list){
3861 Expression var = (Expression) e.Key;
3863 var = var.ResolveLValue (ec, new EmptyExpression (), loc);
3867 resolved_vars [i] = var;
3874 converted_vars [i] = Convert.ImplicitConversion (
3875 ec, var, TypeManager.idisposable_type, loc);
3877 if (converted_vars [i] == null) {
3878 Error_IsNotConvertibleToIDisposable ();
3886 foreach (DictionaryEntry e in var_list){
3887 Expression var = resolved_vars [i];
3888 Expression new_expr = (Expression) e.Value;
3891 a = new Assign (var, new_expr, loc);
3897 converted_vars [i] = var;
3898 assign [i] = (ExpressionStatement) a;
3905 void Error_IsNotConvertibleToIDisposable ()
3907 Report.Error (1674, loc, "`{0}': type used in a using statement must be implicitly convertible to `System.IDisposable'",
3908 TypeManager.CSharpName (expr_type));
3911 bool ResolveExpression (EmitContext ec)
3913 if (!TypeManager.ImplementsInterface (expr_type, TypeManager.idisposable_type)){
3914 if (Convert.ImplicitConversion (ec, expr, TypeManager.idisposable_type, loc) == null) {
3915 Error_IsNotConvertibleToIDisposable ();
3924 // Emits the code for the case of using using a local variable declaration.
3926 void EmitLocalVariableDecls (EmitContext ec)
3928 ILGenerator ig = ec.ig;
3931 for (i = 0; i < assign.Length; i++) {
3932 assign [i].EmitStatement (ec);
3935 ig.BeginExceptionBlock ();
3937 Statement.Emit (ec);
3938 var_list.Reverse ();
3943 void EmitLocalVariableDeclFinally (EmitContext ec)
3945 ILGenerator ig = ec.ig;
3947 int i = assign.Length;
3948 for (int ii = 0; ii < var_list.Count; ++ii){
3949 Expression var = resolved_vars [--i];
3950 Label skip = ig.DefineLabel ();
3952 if (!var.Type.IsValueType) {
3954 ig.Emit (OpCodes.Brfalse, skip);
3955 converted_vars [i].Emit (ec);
3956 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
3958 Expression ml = Expression.MemberLookup(ec.ContainerType, TypeManager.idisposable_type, var.Type, "Dispose", Mono.CSharp.Location.Null);
3960 if (!(ml is MethodGroupExpr)) {
3962 ig.Emit (OpCodes.Box, var.Type);
3963 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
3965 MethodInfo mi = null;
3967 foreach (MethodInfo mk in ((MethodGroupExpr) ml).Methods) {
3968 if (TypeManager.GetParameterData (mk).Count == 0) {
3975 Report.Error(-100, Mono.CSharp.Location.Null, "Internal error: No Dispose method which takes 0 parameters.");
3979 IMemoryLocation mloc = (IMemoryLocation) var;
3981 mloc.AddressOf (ec, AddressOp.Load);
3982 ig.Emit (OpCodes.Call, mi);
3986 ig.MarkLabel (skip);
3989 ig.EndExceptionBlock ();
3991 ig.BeginFinallyBlock ();
3996 void EmitExpression (EmitContext ec)
3999 // Make a copy of the expression and operate on that.
4001 ILGenerator ig = ec.ig;
4002 local_copy = ig.DeclareLocal (expr_type);
4005 ig.Emit (OpCodes.Stloc, local_copy);
4008 ig.BeginExceptionBlock ();
4010 Statement.Emit (ec);
4014 ig.EndExceptionBlock ();
4017 void EmitExpressionFinally (EmitContext ec)
4019 ILGenerator ig = ec.ig;
4020 if (!local_copy.LocalType.IsValueType) {
4021 Label skip = ig.DefineLabel ();
4022 ig.Emit (OpCodes.Ldloc, local_copy);
4023 ig.Emit (OpCodes.Brfalse, skip);
4024 ig.Emit (OpCodes.Ldloc, local_copy);
4025 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4026 ig.MarkLabel (skip);
4028 Expression ml = Expression.MemberLookup(ec.ContainerType, TypeManager.idisposable_type, local_copy.LocalType, "Dispose", Mono.CSharp.Location.Null);
4030 if (!(ml is MethodGroupExpr)) {
4031 ig.Emit (OpCodes.Ldloc, local_copy);
4032 ig.Emit (OpCodes.Box, local_copy.LocalType);
4033 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4035 MethodInfo mi = null;
4037 foreach (MethodInfo mk in ((MethodGroupExpr) ml).Methods) {
4038 if (TypeManager.GetParameterData (mk).Count == 0) {
4045 Report.Error(-100, Mono.CSharp.Location.Null, "Internal error: No Dispose method which takes 0 parameters.");
4049 ig.Emit (OpCodes.Ldloca, local_copy);
4050 ig.Emit (OpCodes.Call, mi);
4055 public override bool Resolve (EmitContext ec)
4057 if (expression_or_block is DictionaryEntry){
4058 expr = (Expression) ((DictionaryEntry) expression_or_block).Key;
4059 var_list = (ArrayList)((DictionaryEntry)expression_or_block).Value;
4061 if (!ResolveLocalVariableDecls (ec))
4064 } else if (expression_or_block is Expression){
4065 expr = (Expression) expression_or_block;
4067 expr = expr.Resolve (ec);
4071 expr_type = expr.Type;
4073 if (!ResolveExpression (ec))
4077 FlowBranchingException branching = ec.StartFlowBranching (this);
4079 bool ok = Statement.Resolve (ec);
4082 ec.KillFlowBranching ();
4086 ResolveFinally (branching);
4087 FlowBranching.Reachability reachability = ec.EndFlowBranching ();
4089 if (!reachability.AlwaysReturns) {
4090 // Unfortunately, System.Reflection.Emit automatically emits a leave
4091 // to the end of the finally block. This is a problem if `returns'
4092 // is true since we may jump to a point after the end of the method.
4093 // As a workaround, emit an explicit ret here.
4094 ec.NeedReturnLabel ();
4100 protected override void DoEmit (EmitContext ec)
4102 if (expression_or_block is DictionaryEntry)
4103 EmitLocalVariableDecls (ec);
4104 else if (expression_or_block is Expression)
4105 EmitExpression (ec);
4108 public override void EmitFinally (EmitContext ec)
4110 if (expression_or_block is DictionaryEntry)
4111 EmitLocalVariableDeclFinally (ec);
4112 else if (expression_or_block is Expression)
4113 EmitExpressionFinally (ec);
4118 /// Implementation of the foreach C# statement
4120 public class Foreach : Statement {
4122 Expression variable;
4124 Statement statement;
4126 CollectionForeach collection;
4128 public Foreach (Expression type, LocalVariableReference var, Expression expr,
4129 Statement stmt, Location l)
4132 this.variable = var;
4138 public Statement Statement {
4139 get { return statement; }
4142 public override bool Resolve (EmitContext ec)
4144 expr = expr.Resolve (ec);
4148 Constant c = expr as Constant;
4149 if (c != null && c.GetValue () == null) {
4150 Report.Error (186, loc, "Use of null is not valid in this context");
4154 TypeExpr texpr = type.ResolveAsTypeTerminal (ec, false);
4158 Type var_type = texpr.Type;
4160 if (expr.eclass == ExprClass.MethodGroup || expr is AnonymousMethod) {
4161 Report.Error (446, expr.Location, "Foreach statement cannot operate on a `{0}'",
4162 expr.ExprClassName);
4167 // We need an instance variable. Not sure this is the best
4168 // way of doing this.
4170 // FIXME: When we implement propertyaccess, will those turn
4171 // out to return values in ExprClass? I think they should.
4173 if (!(expr.eclass == ExprClass.Variable || expr.eclass == ExprClass.Value ||
4174 expr.eclass == ExprClass.PropertyAccess || expr.eclass == ExprClass.IndexerAccess)){
4175 collection.Error_Enumerator ();
4179 if (expr.Type.IsArray) {
4180 array = new ArrayForeach (var_type, variable, expr, statement, loc);
4181 return array.Resolve (ec);
4183 collection = new CollectionForeach (
4184 var_type, variable, expr, statement, loc);
4185 return collection.Resolve (ec);
4189 protected override void DoEmit (EmitContext ec)
4191 ILGenerator ig = ec.ig;
4193 Label old_begin = ec.LoopBegin, old_end = ec.LoopEnd;
4194 ec.LoopBegin = ig.DefineLabel ();
4195 ec.LoopEnd = ig.DefineLabel ();
4197 if (collection != null)
4198 collection.Emit (ec);
4202 ec.LoopBegin = old_begin;
4203 ec.LoopEnd = old_end;
4206 protected class ArrayCounter : TemporaryVariable
4208 public ArrayCounter (Location loc)
4209 : base (TypeManager.int32_type, loc)
4212 public void Initialize (EmitContext ec)
4215 ec.ig.Emit (OpCodes.Ldc_I4_0);
4219 public void Increment (EmitContext ec)
4223 ec.ig.Emit (OpCodes.Ldc_I4_1);
4224 ec.ig.Emit (OpCodes.Add);
4229 protected class ArrayForeach : Statement
4231 Expression variable, expr, conv;
4232 Statement statement;
4235 TemporaryVariable[] lengths;
4236 ArrayCounter[] counter;
4239 TemporaryVariable copy;
4242 public ArrayForeach (Type var_type, Expression var,
4243 Expression expr, Statement stmt, Location l)
4245 this.var_type = var_type;
4246 this.variable = var;
4252 public override bool Resolve (EmitContext ec)
4254 array_type = expr.Type;
4255 rank = array_type.GetArrayRank ();
4257 copy = new TemporaryVariable (array_type, loc);
4260 counter = new ArrayCounter [rank];
4261 lengths = new TemporaryVariable [rank];
4263 ArrayList list = new ArrayList ();
4264 for (int i = 0; i < rank; i++) {
4265 counter [i] = new ArrayCounter (loc);
4266 counter [i].Resolve (ec);
4268 lengths [i] = new TemporaryVariable (TypeManager.int32_type, loc);
4269 lengths [i].Resolve (ec);
4271 list.Add (counter [i]);
4274 access = new ElementAccess (copy, list).Resolve (ec);
4278 conv = Convert.ExplicitConversion (ec, access, var_type, loc);
4284 ec.StartFlowBranching (FlowBranching.BranchingType.Loop, loc);
4285 ec.CurrentBranching.CreateSibling ();
4287 variable = variable.ResolveLValue (ec, conv, loc);
4288 if (variable == null)
4291 ec.StartFlowBranching (FlowBranching.BranchingType.Embedded, loc);
4292 if (!statement.Resolve (ec))
4294 ec.EndFlowBranching ();
4296 // There's no direct control flow from the end of the embedded statement to the end of the loop
4297 ec.CurrentBranching.CurrentUsageVector.Goto ();
4299 ec.EndFlowBranching ();
4304 protected override void DoEmit (EmitContext ec)
4306 ILGenerator ig = ec.ig;
4308 copy.Store (ec, expr);
4310 Label[] test = new Label [rank];
4311 Label[] loop = new Label [rank];
4313 for (int i = 0; i < rank; i++) {
4314 test [i] = ig.DefineLabel ();
4315 loop [i] = ig.DefineLabel ();
4317 lengths [i].EmitThis (ec);
4318 ((ArrayAccess) access).EmitGetLength (ec, i);
4319 lengths [i].EmitStore (ig);
4322 for (int i = 0; i < rank; i++) {
4323 counter [i].Initialize (ec);
4325 ig.Emit (OpCodes.Br, test [i]);
4326 ig.MarkLabel (loop [i]);
4329 ((IAssignMethod) variable).EmitAssign (ec, conv, false, false);
4331 statement.Emit (ec);
4333 ig.MarkLabel (ec.LoopBegin);
4335 for (int i = rank - 1; i >= 0; i--){
4336 counter [i].Increment (ec);
4338 ig.MarkLabel (test [i]);
4339 counter [i].Emit (ec);
4340 lengths [i].Emit (ec);
4341 ig.Emit (OpCodes.Blt, loop [i]);
4344 ig.MarkLabel (ec.LoopEnd);
4348 protected class CollectionForeach : ExceptionStatement
4350 Expression variable, expr;
4351 Statement statement;
4353 TemporaryVariable enumerator;
4357 MethodGroupExpr get_enumerator;
4358 PropertyExpr get_current;
4359 MethodInfo move_next;
4360 Type var_type, enumerator_type;
4362 bool enumerator_found;
4364 public CollectionForeach (Type var_type, Expression var,
4365 Expression expr, Statement stmt, Location l)
4367 this.var_type = var_type;
4368 this.variable = var;
4374 bool GetEnumeratorFilter (EmitContext ec, MethodInfo mi)
4376 Type return_type = mi.ReturnType;
4378 if ((return_type == TypeManager.ienumerator_type) && (mi.DeclaringType == TypeManager.string_type))
4380 // Apply the same optimization as MS: skip the GetEnumerator
4381 // returning an IEnumerator, and use the one returning a
4382 // CharEnumerator instead. This allows us to avoid the
4383 // try-finally block and the boxing.
4388 // Ok, we can access it, now make sure that we can do something
4389 // with this `GetEnumerator'
4392 if (return_type == TypeManager.ienumerator_type ||
4393 TypeManager.ienumerator_type.IsAssignableFrom (return_type) ||
4394 (!RootContext.StdLib && TypeManager.ImplementsInterface (return_type, TypeManager.ienumerator_type))) {
4396 // If it is not an interface, lets try to find the methods ourselves.
4397 // For example, if we have:
4398 // public class Foo : IEnumerator { public bool MoveNext () {} public int Current { get {}}}
4399 // We can avoid the iface call. This is a runtime perf boost.
4400 // even bigger if we have a ValueType, because we avoid the cost
4403 // We have to make sure that both methods exist for us to take
4404 // this path. If one of the methods does not exist, we will just
4405 // use the interface. Sadly, this complex if statement is the only
4406 // way I could do this without a goto
4409 if (return_type.IsInterface ||
4410 !FetchMoveNext (return_type) ||
4411 !FetchGetCurrent (ec, return_type)) {
4412 move_next = TypeManager.bool_movenext_void;
4413 get_current = new PropertyExpr (
4414 ec.ContainerType, TypeManager.ienumerator_getcurrent, loc);
4419 // Ok, so they dont return an IEnumerable, we will have to
4420 // find if they support the GetEnumerator pattern.
4423 if (TypeManager.HasElementType (return_type) || !FetchMoveNext (return_type) || !FetchGetCurrent (ec, return_type)) {
4424 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",
4425 TypeManager.CSharpName (return_type), TypeManager.CSharpSignature (mi));
4430 enumerator_type = return_type;
4431 is_disposable = !enumerator_type.IsSealed ||
4432 TypeManager.ImplementsInterface (
4433 enumerator_type, TypeManager.idisposable_type);
4439 // Retrieves a `public bool MoveNext ()' method from the Type `t'
4441 bool FetchMoveNext (Type t)
4443 MemberList move_next_list;
4445 move_next_list = TypeContainer.FindMembers (
4446 t, MemberTypes.Method,
4447 BindingFlags.Public | BindingFlags.Instance,
4448 Type.FilterName, "MoveNext");
4449 if (move_next_list.Count == 0)
4452 foreach (MemberInfo m in move_next_list){
4453 MethodInfo mi = (MethodInfo) m;
4455 if ((TypeManager.GetParameterData (mi).Count == 0) &&
4456 TypeManager.TypeToCoreType (mi.ReturnType) == TypeManager.bool_type) {
4466 // Retrieves a `public T get_Current ()' method from the Type `t'
4468 bool FetchGetCurrent (EmitContext ec, Type t)
4470 PropertyExpr pe = Expression.MemberLookup (
4471 ec.ContainerType, t, "Current", MemberTypes.Property,
4472 Expression.AllBindingFlags, loc) as PropertyExpr;
4481 // Retrieves a `public void Dispose ()' method from the Type `t'
4483 static MethodInfo FetchMethodDispose (Type t)
4485 MemberList dispose_list;
4487 dispose_list = TypeContainer.FindMembers (
4488 t, MemberTypes.Method,
4489 BindingFlags.Public | BindingFlags.Instance,
4490 Type.FilterName, "Dispose");
4491 if (dispose_list.Count == 0)
4494 foreach (MemberInfo m in dispose_list){
4495 MethodInfo mi = (MethodInfo) m;
4497 if (TypeManager.GetParameterData (mi).Count == 0){
4498 if (mi.ReturnType == TypeManager.void_type)
4505 public void Error_Enumerator ()
4507 if (enumerator_found) {
4511 Report.Error (1579, loc,
4512 "foreach statement cannot operate on variables of type `{0}' because it does not contain a definition for `GetEnumerator' or is not accessible",
4513 TypeManager.CSharpName (expr.Type));
4516 bool TryType (EmitContext ec, Type t)
4518 MethodGroupExpr mg = Expression.MemberLookup (
4519 ec.ContainerType, t, "GetEnumerator", MemberTypes.Method,
4520 Expression.AllBindingFlags, loc) as MethodGroupExpr;
4524 foreach (MethodBase mb in mg.Methods) {
4525 if (TypeManager.GetParameterData (mb).Count != 0)
4528 // Check whether GetEnumerator is public
4529 if ((mb.Attributes & MethodAttributes.Public) != MethodAttributes.Public)
4532 if (TypeManager.IsOverride (mb))
4535 enumerator_found = true;
4537 if (!GetEnumeratorFilter (ec, (MethodInfo) mb))
4540 MethodInfo[] mi = new MethodInfo[] { (MethodInfo) mb };
4541 get_enumerator = new MethodGroupExpr (mi, loc);
4543 if (t != expr.Type) {
4544 expr = Convert.ExplicitConversion (
4547 throw new InternalErrorException ();
4550 get_enumerator.InstanceExpression = expr;
4551 get_enumerator.IsBase = t != expr.Type;
4559 bool ProbeCollectionType (EmitContext ec, Type t)
4561 for (Type tt = t; tt != null && tt != TypeManager.object_type;){
4562 if (TryType (ec, tt))
4568 // Now try to find the method in the interfaces
4571 Type [] ifaces = t.GetInterfaces ();
4573 foreach (Type i in ifaces){
4574 if (TryType (ec, i))
4579 // Since TypeBuilder.GetInterfaces only returns the interface
4580 // types for this type, we have to keep looping, but once
4581 // we hit a non-TypeBuilder (ie, a Type), then we know we are
4582 // done, because it returns all the types
4584 if ((t is TypeBuilder))
4593 public override bool Resolve (EmitContext ec)
4595 enumerator_type = TypeManager.ienumerator_type;
4596 is_disposable = true;
4598 if (!ProbeCollectionType (ec, expr.Type)) {
4599 Error_Enumerator ();
4603 enumerator = new TemporaryVariable (enumerator_type, loc);
4604 enumerator.Resolve (ec);
4606 init = new Invocation (get_enumerator, new ArrayList ());
4607 init = init.Resolve (ec);
4611 Expression move_next_expr;
4613 MemberInfo[] mi = new MemberInfo[] { move_next };
4614 MethodGroupExpr mg = new MethodGroupExpr (mi, loc);
4615 mg.InstanceExpression = enumerator;
4617 move_next_expr = new Invocation (mg, new ArrayList ());
4620 get_current.InstanceExpression = enumerator;
4622 Statement block = new CollectionForeachStatement (
4623 var_type, variable, get_current, statement, loc);
4625 loop = new While (move_next_expr, block, loc);
4629 FlowBranchingException branching = null;
4631 branching = ec.StartFlowBranching (this);
4633 if (!loop.Resolve (ec))
4636 if (is_disposable) {
4637 ResolveFinally (branching);
4638 ec.EndFlowBranching ();
4640 emit_finally = true;
4645 protected override void DoEmit (EmitContext ec)
4647 ILGenerator ig = ec.ig;
4649 enumerator.Store (ec, init);
4652 // Protect the code in a try/finalize block, so that
4653 // if the beast implement IDisposable, we get rid of it
4655 if (is_disposable && emit_finally)
4656 ig.BeginExceptionBlock ();
4661 // Now the finally block
4663 if (is_disposable) {
4666 ig.EndExceptionBlock ();
4671 public override void EmitFinally (EmitContext ec)
4673 ILGenerator ig = ec.ig;
4675 if (enumerator_type.IsValueType) {
4676 MethodInfo mi = FetchMethodDispose (enumerator_type);
4678 enumerator.EmitLoadAddress (ec);
4679 ig.Emit (OpCodes.Call, mi);
4681 enumerator.Emit (ec);
4682 ig.Emit (OpCodes.Box, enumerator_type);
4683 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4686 Label call_dispose = ig.DefineLabel ();
4688 enumerator.Emit (ec);
4689 ig.Emit (OpCodes.Isinst, TypeManager.idisposable_type);
4690 ig.Emit (OpCodes.Dup);
4691 ig.Emit (OpCodes.Brtrue_S, call_dispose);
4692 ig.Emit (OpCodes.Pop);
4694 Label end_finally = ig.DefineLabel ();
4695 ig.Emit (OpCodes.Br, end_finally);
4697 ig.MarkLabel (call_dispose);
4698 ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
4699 ig.MarkLabel (end_finally);
4704 protected class CollectionForeachStatement : Statement
4707 Expression variable, current, conv;
4708 Statement statement;
4711 public CollectionForeachStatement (Type type, Expression variable,
4712 Expression current, Statement statement,
4716 this.variable = variable;
4717 this.current = current;
4718 this.statement = statement;
4722 public override bool Resolve (EmitContext ec)
4724 current = current.Resolve (ec);
4725 if (current == null)
4728 conv = Convert.ExplicitConversion (ec, current, type, loc);
4732 assign = new Assign (variable, conv, loc);
4733 if (assign.Resolve (ec) == null)
4736 if (!statement.Resolve (ec))
4742 protected override void DoEmit (EmitContext ec)
4744 assign.EmitStatement (ec);
4745 statement.Emit (ec);