2008-06-11 Martin Baulig <martin@ximian.com>
[mono.git] / mcs / mcs / iterators.cs
index 374cfb2292c882e1b42797b9a3a398cf436f6594..c659678a52c50f3e9585de8066ab5498cda067ba 100644 (file)
@@ -4,7 +4,7 @@
 // Author:
 //   Miguel de Icaza (miguel@ximian.com)
 //
-// (C) 2003 Ximian, Inc.
+// Copyright 2003 Ximian, Inc.
 //
 // TODO:
 //    Flow analysis for Yield.
@@ -21,11 +21,12 @@ using System.Reflection.Emit;
 
 namespace Mono.CSharp {
 
-       public class Yield : Statement {
+       public class Yield : ResumableStatement {
                Expression expr;
-               ArrayList finally_blocks;
                bool unwind_protect;
 
+               int resume_pc;
+
                public Yield (Expression expr, Location l)
                {
                        this.expr = expr;
@@ -34,12 +35,6 @@ namespace Mono.CSharp {
 
                public static bool CheckContext (EmitContext ec, Location loc, bool isYieldBreak)
                {
-                       if (ec.InFinally) {
-                               Report.Error (1625, loc, "Cannot yield in the body of a " +
-                                             "finally clause");
-                               return false;
-                       }
-
                        for (Block block = ec.CurrentBlock; block != null; block = block.Parent) {
                                if (!block.Unsafe)
                                        continue;
@@ -59,19 +54,6 @@ namespace Mono.CSharp {
                                return false;
                        }
 
-                       if (isYieldBreak)
-                               return true;
-
-                       if (ec.InCatch) {
-                               Report.Error (1631, loc, "Cannot yield a value in the body of a catch clause");
-                               return false;
-                       }
-
-                       if (ec.CurrentBranching.InTryWithCatch ()) {
-                               Report.Error (1626, loc, "Cannot yield a value in the body of a try block with a catch clause");
-                               return false;
-                       }
-
                        return true;
                }
                
@@ -96,13 +78,14 @@ namespace Mono.CSharp {
                                        return false;
                        }
 
-                       unwind_protect = ec.CurrentBranching.StealFinallyClauses (ref finally_blocks);
+                       unwind_protect = ec.CurrentBranching.AddResumePoint (this, loc, out resume_pc);
+
                        return true;
                }
 
                protected override void DoEmit (EmitContext ec)
                {
-                       ec.CurrentIterator.MarkYield (ec, expr, unwind_protect, finally_blocks);
+                       ec.CurrentIterator.MarkYield (ec, expr, resume_pc, unwind_protect, resume_point);
                }
 
                protected override void CloneTo (CloneContext clonectx, Statement t)
@@ -113,22 +96,20 @@ namespace Mono.CSharp {
                }
        }
 
-       public class YieldBreak : Statement {
-               bool unwind_protect;
+       public class YieldBreak : ExitStatement {
                public YieldBreak (Location l)
                {
                        loc = l;
                }
 
-               public override bool Resolve (EmitContext ec)
+               public override void Error_FinallyClause ()
                {
-                       if (!Yield.CheckContext (ec, loc, true))
-                               return false;
+                       Report.Error (1625, loc, "Cannot yield in the body of a finally clause");
+               }
 
-                       // not exactly a 'return' but close enough
-                       unwind_protect = ec.CurrentBranching.AddReturnOrigin (ec.CurrentBranching.CurrentUsageVector, loc);
-                       ec.CurrentBranching.CurrentUsageVector.Goto ();
-                       return true;
+               protected override bool DoResolve (EmitContext ec)
+               {
+                       return Yield.CheckContext (ec, loc, true);
                }
 
                protected override void DoEmit (EmitContext ec)
@@ -217,7 +198,7 @@ namespace Mono.CSharp {
                        list.Add (generic_enumerator_type);
 #endif
 
-                       Bases = list;
+                       type_bases = list;
 
                        return base.GetClassBases (out base_class);
                }
@@ -301,7 +282,7 @@ namespace Mono.CSharp {
                void Define_Current (bool is_generic)
                {
                        MemberName left;
-                       Expression type;
+                       TypeExpr type;
 
                        if (is_generic) {
                                left = new MemberName (
@@ -363,11 +344,11 @@ namespace Mono.CSharp {
                        protected override bool DoResolveInternal (EmitContext ec)
                        {
                                if (this is EnumeratorScopeInitializer)
-                                       state = Iterator.State.Running;
+                                       state = Iterator.State.Start;
                                else if (Host.Iterator.IsEnumerable)
                                        state = Iterator.State.Uninitialized;
                                else
-                                       state = Iterator.State.Running;
+                                       state = Iterator.State.Start;
 
                                return base.DoResolveInternal (ec);
                        }
@@ -409,7 +390,7 @@ namespace Mono.CSharp {
                                host.AddMethod (this);
 
                                Block = new ToplevelBlock (host.Iterator.Container.Toplevel, null, Location);
-                               Block.AddStatement (new GetEnumeratorStatement (host, Type));
+                               Block.AddStatement (new GetEnumeratorStatement (host, type_name));
                        }
 
                        public override EmitContext CreateEmitContext (DeclSpace tc, ILGenerator ig)
@@ -421,6 +402,11 @@ namespace Mono.CSharp {
                                return ec;
                        }
 
+                       public override void EmitExtraSymbolInfo (SourceMethod source)
+                       {
+                               source.SetCompilerGenerated ();
+                       }
+
                        protected class GetEnumeratorStatement : Statement
                        {
                                IteratorHost host;
@@ -471,7 +457,7 @@ namespace Mono.CSharp {
 
                                        ig.Emit (OpCodes.Ldarg_0);
                                        ig.Emit (OpCodes.Ldflda, host.PC.FieldBuilder);
-                                       ig.Emit (OpCodes.Ldc_I4, (int) Iterator.State.Running);
+                                       ig.Emit (OpCodes.Ldc_I4, (int) Iterator.State.Start);
                                        ig.Emit (OpCodes.Ldc_I4, (int) Iterator.State.Uninitialized);
                                        ig.Emit (OpCodes.Call, ce);
 
@@ -518,6 +504,11 @@ namespace Mono.CSharp {
                                return ec;
                        }
 
+                       public override void EmitExtraSymbolInfo (SourceMethod source)
+                       {
+                               source.SetCompilerGenerated ();
+                       }
+
                        protected class DisposeMethodStatement : Statement
                        {
                                Iterator iterator;
@@ -594,12 +585,7 @@ namespace Mono.CSharp {
 
                        public override bool Resolve (EmitContext ec)
                        {
-                               if (TypeManager.invalid_operation_exception_ctor == null) {
-                                       Type t = TypeManager.CoreLookupType ("System", "InvalidOperationException", Kind.Class, true);
-                                       if (t != null)
-                                               TypeManager.invalid_operation_exception_ctor = TypeManager.GetPredefinedConstructor (t, loc, Type.EmptyTypes);
-                               }
-
+                               // We emit a 'ret', so prevent the enclosing TopLevelBlock from emitting one too
                                ec.CurrentBranching.CurrentUsageVector.Goto ();
                                return true;
                        }
@@ -607,17 +593,7 @@ namespace Mono.CSharp {
                        protected override void DoEmit (EmitContext ec)
                        {
                                ILGenerator ig = ec.ig;
-                               Label label_ok = ig.DefineLabel ();
-
-                               ig.Emit (OpCodes.Ldarg_0);
-                               ig.Emit (OpCodes.Ldfld, host.PC.FieldBuilder);
-                               ig.Emit (OpCodes.Ldc_I4, (int) Iterator.State.Running);
-                               ig.Emit (OpCodes.Bgt, label_ok);
 
-                               ig.Emit (OpCodes.Newobj, TypeManager.invalid_operation_exception_ctor);
-                               ig.Emit (OpCodes.Throw);
-
-                               ig.MarkLabel (label_ok);
                                ig.Emit (OpCodes.Ldarg_0);
                                ig.Emit (OpCodes.Ldfld, host.CurrentField.FieldBuilder);
                                if (!is_generic)
@@ -639,102 +615,120 @@ namespace Mono.CSharp {
                // The state as we generate the iterator
                //
                Label move_next_ok, move_next_error;
-               LocalBuilder skip_finally;
+               LocalBuilder skip_finally, current_pc;
 
                public LocalBuilder SkipFinally {
                        get { return skip_finally; }
                }
 
-               ArrayList resume_points = new ArrayList ();
-               int pc;
-               
+               public LocalBuilder CurrentPC {
+                       get { return current_pc; }
+               }
+
                public readonly Type OriginalIteratorType;
                public readonly IteratorHost IteratorHost;
 
                public enum State {
-                       Uninitialized   = -2,
-                       After,
-                       Running
+                       Running = -3, // Used only in CurrentPC, never stored into $PC
+                       Uninitialized = -2,
+                       After = -1,
+                       Start = 0
                }
 
                public void EmitYieldBreak (ILGenerator ig, bool unwind_protect)
                {
-                       ig.Emit (OpCodes.Ldarg_0);
-                       IntConstant.EmitInt (ig, (int) State.After);
-                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
                        ig.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, move_next_error);
                }
 
-               internal void EmitMoveNext (EmitContext ec, Block original_block)
+               void EmitMoveNext_NoResumePoints (EmitContext ec, Block original_block)
                {
                        ILGenerator ig = ec.ig;
 
-                       move_next_ok = ig.DefineLabel ();
-                       move_next_error = ig.DefineLabel ();
-
-                       LocalBuilder retval = ec.GetTemporaryLocal (TypeManager.int32_type);
-                       skip_finally = ec.GetTemporaryLocal (TypeManager.bool_type);
-
-                       ig.Emit (OpCodes.Ldc_I4_0);
-                       ig.Emit (OpCodes.Stloc, skip_finally);
-
-                       ig.BeginExceptionBlock ();
+                       ig.Emit (OpCodes.Ldarg_0);
+                       ig.Emit (OpCodes.Ldfld, IteratorHost.PC.FieldBuilder);
 
-                       Label dispatcher = ig.DefineLabel ();
-                       ig.Emit (OpCodes.Br, dispatcher);
+                       ig.Emit (OpCodes.Ldarg_0);
+                       IntConstant.EmitInt (ig, (int) State.After);
+                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
 
-                       ResumePoint entry_point = new ResumePoint (null);
-                       resume_points.Add (entry_point);
-                       entry_point.Define (ig);
+                       // We only care if the PC is zero (start executing) or non-zero (don't do anything)
+                       ig.Emit (OpCodes.Brtrue, move_next_error);
 
                        SymbolWriter.StartIteratorBody (ec.ig);
-
                        original_block.Emit (ec);
-
                        SymbolWriter.EndIteratorBody (ec.ig);
 
-                       EmitYieldBreak (ig, false);
+                       ig.MarkLabel (move_next_error);
+                       ig.Emit (OpCodes.Ldc_I4_0);
+                       ig.Emit (OpCodes.Ret);
+               }
 
-                       SymbolWriter.StartIteratorDispatcher (ec.ig);
+               internal void EmitMoveNext (EmitContext ec, Block original_block)
+               {
+                       ILGenerator ig = ec.ig;
 
-                       ig.MarkLabel (dispatcher);
+                       move_next_ok = ig.DefineLabel ();
+                       move_next_error = ig.DefineLabel ();
 
-                       Label [] labels = new Label [resume_points.Count];
-                       for (int i = 0; i < labels.Length; i++)
-                               labels [i] = ((ResumePoint) resume_points [i]).Label;
+                       if (resume_points == null) {
+                               EmitMoveNext_NoResumePoints (ec, original_block);
+                               return;
+                       }
 
+                       current_pc = ec.GetTemporaryLocal (TypeManager.uint32_type);
                        ig.Emit (OpCodes.Ldarg_0);
                        ig.Emit (OpCodes.Ldfld, IteratorHost.PC.FieldBuilder);
-                       ig.Emit (OpCodes.Switch, labels);
+                       ig.Emit (OpCodes.Stloc, current_pc);
 
-                       SymbolWriter.EndIteratorDispatcher (ec.ig);
+                       // We're actually in state 'running', but this is as good a PC value as any if there's an abnormal exit
+                       ig.Emit (OpCodes.Ldarg_0);
+                       IntConstant.EmitInt (ig, (int) State.After);
+                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
 
-                       Label end = ig.DefineLabel ();
+                       Label [] labels = new Label [1 + resume_points.Count];
+                       labels [0] = ig.DefineLabel ();
 
-                       SymbolWriter.StartIteratorDispatcher (ec.ig);
+                       bool need_skip_finally = false;
+                       for (int i = 0; i < resume_points.Count; ++i) {
+                               ResumableStatement s = (ResumableStatement) resume_points [i];
+                               need_skip_finally |= s is ExceptionStatement;
+                               labels [i+1] = s.PrepareForEmit (ec);
+                       }
 
-                       ig.MarkLabel (move_next_error);
-                       ig.Emit (OpCodes.Ldc_I4_0); 
-                       ig.Emit (OpCodes.Stloc, retval);
-                       ig.Emit (OpCodes.Leave, end);
+                       if (need_skip_finally) {
+                               skip_finally = ec.GetTemporaryLocal (TypeManager.bool_type);
+                               ig.Emit (OpCodes.Ldc_I4_0);
+                               ig.Emit (OpCodes.Stloc, skip_finally);
+                       }
 
-                       ig.MarkLabel (move_next_ok);
-                       ig.Emit (OpCodes.Ldc_I4_1);
-                       ig.Emit (OpCodes.Stloc, retval);
-                       ig.Emit (OpCodes.Leave, end);
+                       SymbolWriter.StartIteratorDispatcher (ec.ig);
+                       ig.Emit (OpCodes.Ldloc, current_pc);
+                       ig.Emit (OpCodes.Switch, labels);
 
+                       ig.Emit (OpCodes.Br, move_next_error);
                        SymbolWriter.EndIteratorDispatcher (ec.ig);
 
-                       ig.BeginFaultBlock ();
+                       ig.MarkLabel (labels [0]);
+
+                       SymbolWriter.StartIteratorBody (ec.ig);
+                       original_block.Emit (ec);
+                       SymbolWriter.EndIteratorBody (ec.ig);
+
+                       SymbolWriter.StartIteratorDispatcher (ec.ig);
 
                        ig.Emit (OpCodes.Ldarg_0);
-                       ig.Emit (OpCodes.Callvirt, IteratorHost.Dispose);
+                       IntConstant.EmitInt (ig, (int) State.After);
+                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
 
-                       ig.EndExceptionBlock ();
+                       ig.MarkLabel (move_next_error);
+                       ig.Emit (OpCodes.Ldc_I4_0);
+                       ig.Emit (OpCodes.Ret);
 
-                       ig.MarkLabel (end);
-                       ig.Emit (OpCodes.Ldloc, retval);
+                       ig.MarkLabel (move_next_ok);
+                       ig.Emit (OpCodes.Ldc_I4_1);
                        ig.Emit (OpCodes.Ret);
+
+                       SymbolWriter.EndIteratorDispatcher (ec.ig);
                }
 
                public void EmitDispose (EmitContext ec)
@@ -742,70 +736,59 @@ namespace Mono.CSharp {
                        ILGenerator ig = ec.ig;
 
                        Label end = ig.DefineLabel ();
-                       Label dispatcher = ig.DefineLabel ();
-                       ig.Emit (OpCodes.Br, dispatcher);
-
-                       Label [] labels = new Label [resume_points.Count];
-                       for (int i = 0; i < labels.Length; i++) {
-                               ResumePoint point = (ResumePoint) resume_points [i];
 
-                               if (point.FinallyBlocks == null) {
-                                       labels [i] = end;
+                       Label [] labels = null;
+                       int n_resume_points = resume_points == null ? 0 : resume_points.Count;
+                       for (int i = 0; i < n_resume_points; ++i) {
+                               ResumableStatement s = (ResumableStatement) resume_points [i];
+                               Label ret = s.PrepareForDispose (ec, end);
+                               if (ret.Equals (end) && labels == null)
                                        continue;
+                               if (labels == null) {
+                                       labels = new Label [resume_points.Count + 1];
+                                       for (int j = 0; j <= i; ++j)
+                                               labels [j] = end;
                                }
-
-                               labels [i] = ig.DefineLabel ();
-                               ig.MarkLabel (labels [i]);
-
-                               ig.BeginExceptionBlock ();
-                               ig.BeginFinallyBlock ();
-
-                               foreach (ExceptionStatement stmt in point.FinallyBlocks) {
-                                       if (stmt != null)
-                                               stmt.EmitFinallyBody (ec);
-                               }
-
-                               ig.EndExceptionBlock ();
-                               ig.Emit (OpCodes.Br, end);
+                               labels [i+1] = ret;
                        }
 
-                       ig.MarkLabel (dispatcher);
-                       ig.Emit (OpCodes.Ldarg_0);
-                       ig.Emit (OpCodes.Ldfld, IteratorHost.PC.FieldBuilder);
-                       ig.Emit (OpCodes.Switch, labels);
+                       if (labels != null) {
+                               current_pc = ec.GetTemporaryLocal (TypeManager.uint32_type);
+                               ig.Emit (OpCodes.Ldarg_0);
+                               ig.Emit (OpCodes.Ldfld, IteratorHost.PC.FieldBuilder);
+                               ig.Emit (OpCodes.Stloc, current_pc);
+                       }
 
                        ig.Emit (OpCodes.Ldarg_0);
                        IntConstant.EmitInt (ig, (int) State.After);
                        ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
 
+                       if (labels != null) {
+                               //SymbolWriter.StartIteratorDispatcher (ec.ig);
+                               ig.Emit (OpCodes.Ldloc, current_pc);
+                               ig.Emit (OpCodes.Switch, labels);
+                               //SymbolWriter.EndIteratorDispatcher (ec.ig);
+
+                               foreach (ResumableStatement s in resume_points)
+                                       s.EmitForDispose (ec, this, end, true);
+                       }
+
                        ig.MarkLabel (end);
                }
 
-               protected class ResumePoint
+               ArrayList resume_points;
+               public int AddResumePoint (ResumableStatement stmt, Location loc)
                {
-                       public Label Label;
-                       public readonly ExceptionStatement[] FinallyBlocks;
-
-                       public ResumePoint (ArrayList list)
-                       {
-                               if (list != null) {
-                                       FinallyBlocks = new ExceptionStatement [list.Count];
-                                       list.CopyTo (FinallyBlocks, 0);
-                               }
-                       }
-
-                       public void Define (ILGenerator ig)
-                       {
-                               Label = ig.DefineLabel ();
-                               ig.MarkLabel (Label);
-                       }
+                       if (resume_points == null)
+                               resume_points = new ArrayList ();
+                       resume_points.Add (stmt);
+                       return resume_points.Count;
                }
 
                //
                // Called back from Yield
                //
-               public void MarkYield (EmitContext ec, Expression expr, bool unwind_protect,
-                                      ArrayList finally_blocks)
+               public void MarkYield (EmitContext ec, Expression expr, int resume_pc, bool unwind_protect, Label resume_point)
                {
                        ILGenerator ig = ec.ig;
 
@@ -814,22 +797,21 @@ namespace Mono.CSharp {
                        expr.Emit (ec);
                        ig.Emit (OpCodes.Stfld, IteratorHost.CurrentField.FieldBuilder);
 
-                       // increment pc
-                       pc++;
+                       // store resume program-counter
                        ig.Emit (OpCodes.Ldarg_0);
-                       IntConstant.EmitInt (ig, pc);
+                       IntConstant.EmitInt (ig, resume_pc);
                        ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
 
                        // mark finally blocks as disabled
-                       ig.Emit (OpCodes.Ldc_I4_1);
-                       ig.Emit (OpCodes.Stloc, skip_finally);
+                       if (unwind_protect && skip_finally != null) {
+                               ig.Emit (OpCodes.Ldc_I4_1);
+                               ig.Emit (OpCodes.Stloc, skip_finally);
+                       }
 
                        // Return ok
                        ig.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, move_next_ok);
 
-                       ResumePoint point = new ResumePoint (finally_blocks);
-                       resume_points.Add (point);
-                       point.Define (ig);
+                       ig.MarkLabel (resume_point);
                }
 
                public override string ContainerType {
@@ -971,26 +953,6 @@ namespace Mono.CSharp {
                        throw new NotSupportedException ();
                }
 
-               protected class MoveNextStatement : Statement {
-                       Iterator iterator;
-
-                       public MoveNextStatement (Iterator iterator, Location loc)
-                       {
-                               this.loc = loc;
-                               this.iterator = iterator;
-                       }
-
-                       public override bool Resolve (EmitContext ec)
-                       {
-                               return iterator.OriginalBlock.Resolve (ec);
-                       }
-
-                       protected override void DoEmit (EmitContext ec)
-                       {
-                               iterator.EmitMoveNext (ec, iterator.Block);
-                       }
-               }
-
                public Type IteratorType {
                        get { return IteratorHost.IteratorType; }
                }
@@ -1026,6 +988,11 @@ namespace Mono.CSharp {
                        }
                }
 
+               public override Expression CreateExpressionTree (EmitContext ec)
+               {
+                       throw new NotSupportedException ("ET");
+               }
+
                public static Iterator CreateIterator (IMethodData method, DeclSpace parent,
                                                       GenericMethod generic, int modifiers)
                {