2010-01-15 Carlos Alberto Cortez <calberto.cortez@gmail.com>
[mono.git] / mcs / mcs / iterators.cs
index da0223abe6fae1c62bcfdb1cfee34b59beae8281..20d6741406bac6b9cae6b96914458872c908bfca 100644 (file)
 //
 
 using System;
-using System.Collections;
+using System.Collections.Generic;
 using System.Reflection;
 using System.Reflection.Emit;
 
 namespace Mono.CSharp {
 
-       public class Yield : ResumableStatement {
+       class Yield : ResumableStatement {
                Expression expr;
                bool unwind_protect;
-
+               Iterator iterator;
                int resume_pc;
 
                public Yield (Expression expr, Location l)
@@ -33,22 +33,14 @@ namespace Mono.CSharp {
                        loc = l;
                }
 
-               public static bool CheckContext (EmitContext ec, Location loc, bool isYieldBreak)
+               public static bool CheckContext (ResolveContext ec, Location loc)
                {
-                       for (Block block = ec.CurrentBlock; block != null; block = block.Parent) {
-                               if (!block.Unsafe)
-                                       continue;
-
-                               Report.Error (1629, loc, "Unsafe code may not appear in iterators");
-                               return false;
-                       }
-
                        //
                        // We can't use `ec.InUnsafe' here because it's allowed to have an iterator
                        // inside an unsafe class.  See test-martin-29.cs for an example.
                        //
                        if (!ec.CurrentAnonymousMethod.IsIterator) {
-                               Report.Error (1621, loc,
+                               ec.Report.Error (1621, loc,
                                              "The yield statement cannot be used inside " +
                                              "anonymous method blocks");
                                return false;
@@ -62,7 +54,7 @@ namespace Mono.CSharp {
                        expr.MutateHoistedGenericType (storey);
                }
                
-               public override bool Resolve (EmitContext ec)
+               public override bool Resolve (BlockContext ec)
                {
                        expr = expr.Resolve (ec);
                        if (expr == null)
@@ -71,10 +63,10 @@ namespace Mono.CSharp {
                        Report.Debug (64, "RESOLVE YIELD #1", this, ec, expr, expr.GetType (),
                                      ec.CurrentAnonymousMethod, ec.CurrentIterator);
 
-                       if (!CheckContext (ec, loc, false))
+                       if (!CheckContext (ec, loc))
                                return false;
 
-                       Iterator iterator = ec.CurrentIterator;
+                       iterator = ec.CurrentIterator;
                        if (expr.Type != iterator.OriginalIteratorType) {
                                expr = Convert.ImplicitConversionRequired (
                                        ec, expr, iterator.OriginalIteratorType, loc);
@@ -82,14 +74,15 @@ namespace Mono.CSharp {
                                        return false;
                        }
 
-                       unwind_protect = ec.CurrentBranching.AddResumePoint (this, loc, out resume_pc);
+                       if (!ec.CurrentBranching.CurrentUsageVector.IsUnreachable)
+                               unwind_protect = ec.CurrentBranching.AddResumePoint (this, loc, out resume_pc);
 
                        return true;
                }
 
                protected override void DoEmit (EmitContext ec)
                {
-                       ec.CurrentIterator.MarkYield (ec, expr, resume_pc, unwind_protect, resume_point);
+                       iterator.MarkYield (ec, expr, resume_pc, unwind_protect, resume_point);
                }
 
                protected override void CloneTo (CloneContext clonectx, Statement t)
@@ -100,25 +93,34 @@ namespace Mono.CSharp {
                }
        }
 
-       public class YieldBreak : ExitStatement {
+       public class YieldBreak : ExitStatement
+       {
+               Iterator iterator;
+
                public YieldBreak (Location l)
                {
                        loc = l;
                }
 
-               public override void Error_FinallyClause ()
+               public override void Error_FinallyClause (Report Report)
                {
                        Report.Error (1625, loc, "Cannot yield in the body of a finally clause");
                }
 
-               protected override bool DoResolve (EmitContext ec)
+               protected override void CloneTo (CloneContext clonectx, Statement target)
                {
-                       return Yield.CheckContext (ec, loc, true);
+                       throw new NotSupportedException ();
+               }
+
+               protected override bool DoResolve (BlockContext ec)
+               {
+                       iterator = ec.CurrentIterator;
+                       return Yield.CheckContext (ec, loc);
                }
 
                protected override void DoEmit (EmitContext ec)
                {
-                       ec.CurrentIterator.EmitYieldBreak (ec.ig, unwind_protect);
+                       iterator.EmitYieldBreak (ec.ig, unwind_protect);
                }
 
                public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
@@ -133,16 +135,23 @@ namespace Mono.CSharp {
        class IteratorStatement : Statement
        {
                Iterator iterator;
-               ExplicitBlock original_block;
+               Block original_block;
 
-               public IteratorStatement (Iterator iterator, ExplicitBlock original_block)
+               public IteratorStatement (Iterator iterator, Block original_block)
                {
                        this.iterator = iterator;
                        this.original_block = original_block;
                        this.loc = iterator.Location;
                }
 
-               public override bool Resolve (EmitContext ec)
+               protected override void CloneTo (CloneContext clonectx, Statement target)
+               {
+                       IteratorStatement t = (IteratorStatement) target;
+                       t.original_block = (ExplicitBlock) original_block.Clone (clonectx);
+                       t.iterator = (Iterator) iterator.Clone (clonectx);
+               }
+
+               public override bool Resolve (BlockContext ec)
                {
                        ec.StartFlowBranching (iterator);
                        bool ok = original_block.Resolve (ec);
@@ -164,243 +173,92 @@ namespace Mono.CSharp {
 
        public class IteratorStorey : AnonymousMethodStorey
        {
-               public readonly Iterator Iterator;
-
-               TypeExpr iterator_type_expr;
-               Field pc_field;
-               Field current_field;
-
-               TypeExpr enumerator_type;
-               TypeExpr enumerable_type;
-               TypeArguments generic_args;
-               TypeExpr generic_enumerator_type;
-#if GMCS_SOURCE                
-               TypeExpr generic_enumerable_type;
-#endif
-
-               int local_name_idx;
-
-               public IteratorStorey (Iterator iterator)
-                       : base (iterator.Container.Toplevel, iterator.Host,
-                         iterator.OriginalMethod as MemberBase, iterator.GenericMethod, "Iterator")
-               {
-                       this.Iterator = iterator;
-               }
-
-               public Field PC {
-                       get { return pc_field; }
-               }
-
-               public Field CurrentField {
-                       get { return current_field; }
-               }
-
-               public ArrayList HoistedParameters {
-                       get { return hoisted_params; }
-               }
-
-               public override TypeExpr [] GetClassBases (out TypeExpr base_class)
-               {
-                       iterator_type_expr = new TypeExpression (MutateType (Iterator.OriginalIteratorType), Location);
-
-#if GMCS_SOURCE
-                       generic_args = new TypeArguments (Location);
-                       generic_args.Add (iterator_type_expr);
-#endif
-
-                       ArrayList list = new ArrayList ();
-                       if (Iterator.IsEnumerable) {
-                               enumerable_type = new TypeExpression (
-                                       TypeManager.ienumerable_type, Location);
-                               list.Add (enumerable_type);
-
-#if GMCS_SOURCE
-                               generic_enumerable_type = new ConstructedType (
-                                       TypeManager.generic_ienumerable_type,
-                                       generic_args, Location);
-                               list.Add (generic_enumerable_type);
-#endif
-                       }
-
-                       enumerator_type = new TypeExpression (
-                               TypeManager.ienumerator_type, Location);
-                       list.Add (enumerator_type);
-
-                       list.Add (new TypeExpression (TypeManager.idisposable_type, Location));
-
-#if GMCS_SOURCE
-                       generic_enumerator_type = new ConstructedType (
-                               TypeManager.generic_ienumerator_type,
-                               generic_args, Location);
-                       list.Add (generic_enumerator_type);
-#endif
-
-                       type_bases = list;
-
-                       return base.GetClassBases (out base_class);
-               }
-
-               protected override string GetVariableMangledName (LocalInfo local_info)
-               {
-                       return "<" + local_info.Name + ">__" + local_name_idx++.ToString ();
-               }
-
-               public void DefineIteratorMembers ()
-               {
-                       pc_field = AddCompilerGeneratedField ("$PC", TypeManager.system_int32_expr);
-                       current_field = AddCompilerGeneratedField ("$current", iterator_type_expr);
-
-#if GMCS_SOURCE
-                       Define_Current (true);
-#endif
-                       Define_Current (false);
-                       new DisposeMethod (this);
-                       Define_Reset ();
-
-                       if (Iterator.IsEnumerable) {
-                               new GetEnumeratorMethod (this, false);
-#if GMCS_SOURCE
-                               new GetEnumeratorMethod (this, true);
-#endif
-                       }
-
-                       DoResolveMembers ();
-               }
-
-               void Define_Current (bool is_generic)
-               {
-                       MemberName left;
-                       TypeExpr type;
-
-                       if (is_generic) {
-                               left = new MemberName (
-                                       "System.Collections.Generic.IEnumerator",
-                                       generic_args, Location);
-                               type = iterator_type_expr;
-                       } else {
-                               left = new MemberName ("System.Collections.IEnumerator", Location);
-                               type = TypeManager.system_object_expr;
-                       }
-
-                       MemberName name = new MemberName (left, "Current", null, Location);
-
-                       ToplevelBlock get_block = new ToplevelBlock (Location);
-                       get_block.AddStatement (new CurrentBlock (this, is_generic));
-
-                       Accessor getter = new Accessor (get_block, 0, null, Location);
-
-                       Property current = new Property (
-                               this, type, Modifiers.DEBUGGER_HIDDEN, false, name, null, getter, null, false);
-                       AddProperty (current);
-               }
-
-               void Define_Reset ()
+               class IteratorMethod : Method
                {
-                       Method reset = new Method (
-                               this, null, TypeManager.system_void_expr,
-                               Modifiers.PUBLIC | Modifiers.DEBUGGER_HIDDEN,
-                               false, new MemberName ("Reset", Location),
-                               Parameters.EmptyReadOnlyParameters, null);
-                       AddMethod (reset);
+                       readonly IteratorStorey host;
 
-                       reset.Block = new ToplevelBlock (Location);
-                       reset.Block.AddStatement (Create_ThrowNotSupported ());
-               }
-
-               Statement Create_ThrowNotSupported ()
-               {
-                       TypeExpr ex_type = new TypeLookupExpression ("System.NotSupportedException");
-
-                       return new Throw (new New (ex_type, null, Location), Location);
-               }
-
-               protected class GetEnumeratorMethod : Method
-               {
-                       public IteratorStorey Host;
-
-                       static MemberName GetMemberName (IteratorStorey host, bool is_generic)
+                       public IteratorMethod (IteratorStorey host, FullNamedExpression returnType, Modifiers mod, MemberName name)
+                               : base (host, null, returnType, mod | Modifiers.DEBUGGER_HIDDEN | Modifiers.COMPILER_GENERATED,
+                                 name, ParametersCompiled.EmptyReadOnlyParameters, null)
                        {
-                               MemberName left;
-                               if (is_generic) {
-                                       left = new MemberName (
-                                               "System.Collections.Generic.IEnumerable",
-                                               host.generic_args, host.Location);
-                               } else {
-                                       left = new MemberName (
-                                               "System.Collections.IEnumerable", host.Location);
-                               }
-
-                               return new MemberName (left, "GetEnumerator", host.Location);
-                       }
-
-                       public GetEnumeratorMethod (IteratorStorey host, bool is_generic)
-                               : base (host, null, is_generic ?
-                                       host.generic_enumerator_type : host.enumerator_type,
-                                       Modifiers.DEBUGGER_HIDDEN, false, GetMemberName (host, is_generic),
-                                       Parameters.EmptyReadOnlyParameters, null)
-                       {
-                               this.Host = host;
-
-                               host.AddMethod (this);
+                               this.host = host;
 
-                               Block = new ToplevelBlock (host.Iterator.Container.Toplevel, null, Location);
-                               Block.AddStatement (new GetEnumeratorStatement (host, type_name));
+                               Block = new ToplevelBlock (Compiler, host.Iterator.Container.Toplevel, ParametersCompiled.EmptyReadOnlyParameters, Location);
                        }
 
-                       public override EmitContext CreateEmitContext (DeclSpace tc, ILGenerator ig)
+                       public override EmitContext CreateEmitContext (ILGenerator ig)
                        {
-                               EmitContext ec = new EmitContext (
-                                       this, tc, this.ds, Location, ig, MemberType, ModFlags, false);
+                               EmitContext ec = new EmitContext (this, ig, MemberType);
 
-                               ec.CurrentAnonymousMethod = Host.Iterator;
+                               ec.CurrentAnonymousMethod = host.Iterator;
                                return ec;
                        }
+               }
 
-                       protected class GetEnumeratorStatement : Statement
+               class GetEnumeratorMethod : IteratorMethod
+               {
+                       sealed class GetEnumeratorStatement : Statement
                        {
                                IteratorStorey host;
-                               Expression type;
+                               IteratorMethod host_method;
 
-                               Expression cast;
+                               Expression new_storey;
 
-                               public GetEnumeratorStatement (IteratorStorey host, Expression type)
+                               public GetEnumeratorStatement (IteratorStorey host, IteratorMethod host_method)
                                {
                                        this.host = host;
-                                       this.type = type;
-                                       loc = host.Location;
+                                       this.host_method = host_method;
+                                       loc = host_method.Location;
                                }
 
-                               public override bool Resolve (EmitContext ec)
+                               protected override void CloneTo (CloneContext clonectx, Statement target)
                                {
-                                       type = type.ResolveAsTypeTerminal (ec, false);
-                                       if ((type == null) || (type.Type == null))
-                                               return false;
+                                       throw new NotSupportedException ();
+                               }
 
+                               public override bool Resolve (BlockContext ec)
+                               {
                                        TypeExpression storey_type_expr = new TypeExpression (host.TypeBuilder, loc);
-                                       Expression new_storey;
+                                       List<Expression> init = null;
+                                       if (host.hoisted_this != null) {
+                                               init = new List<Expression> (host.hoisted_params == null ? 1 : host.HoistedParameters.Count + 1);
+                                               HoistedThis ht = host.hoisted_this;
+                                               FieldExpr from = new FieldExpr (ht.Field, loc);
+                                               from.InstanceExpression = CompilerGeneratedThis.Instance;
+                                               init.Add (new ElementInitializer (ht.Field.Name, from, loc));
+                                       }
+
                                        if (host.hoisted_params != null) {
-                                               ArrayList init = new ArrayList (host.HoistedParameters.Count);
-                                               foreach (HoistedParameter hp in host.HoistedParameters) {
-                                                       FieldExpr from = new FieldExpr (hp.Field.FieldBuilder, loc);
+                                               if (init == null)
+                                                       init = new List<Expression> (host.HoistedParameters.Count);
+
+                                               for (int i = 0; i < host.hoisted_params.Count; ++i) {
+                                                       HoistedParameter hp = (HoistedParameter) host.hoisted_params [i];
+                                                       HoistedParameter hp_cp = (HoistedParameter) host.hoisted_params_copy [i];
+
+                                                       FieldExpr from = new FieldExpr (hp_cp.Field, loc);
                                                        from.InstanceExpression = CompilerGeneratedThis.Instance;
+
                                                        init.Add (new ElementInitializer (hp.Field.Name, from, loc));
                                                }
+                                       }
 
-                                               new_storey = new NewInitialize (storey_type_expr, new ArrayList (0),
+                                       if (init != null) {
+                                               new_storey = new NewInitialize (storey_type_expr, null,
                                                        new CollectionOrObjectInitializers (init, loc), loc);
                                        } else {
-                                               new_storey = new New (storey_type_expr, new ArrayList (0), loc);
+                                               new_storey = new New (storey_type_expr, null, loc);
                                        }
 
                                        new_storey = new_storey.Resolve (ec);
                                        if (new_storey != null)
-                                               cast = Convert.ImplicitConversionRequired (ec, new_storey, type.Type, loc);
+                                               new_storey = Convert.ImplicitConversionRequired (ec, new_storey, host_method.MemberType, loc);
 
                                        if (TypeManager.int_interlocked_compare_exchange == null) {
-                                               Type t = TypeManager.CoreLookupType ("System.Threading", "Interlocked", Kind.Class, true);
+                                               Type t = TypeManager.CoreLookupType (ec.Compiler, "System.Threading", "Interlocked", MemberKind.Class, true);
                                                if (t != null) {
                                                        TypeManager.int_interlocked_compare_exchange = TypeManager.GetPredefinedMethod (
-                                                               t, "CompareExchange", loc, TypeManager.GetReferenceType (TypeManager.int32_type),
+                                                               t, "CompareExchange", loc, TypeManager.int32_type,
                                                                TypeManager.int32_type, TypeManager.int32_type);
                                                }
                                        }
@@ -415,20 +273,20 @@ namespace Mono.CSharp {
                                        Label label_init = ig.DefineLabel ();
 
                                        ig.Emit (OpCodes.Ldarg_0);
-                                       ig.Emit (OpCodes.Ldflda, host.PC.FieldBuilder);
-                                       ig.Emit (OpCodes.Ldc_I4, (int) Iterator.State.Start);
-                                       ig.Emit (OpCodes.Ldc_I4, (int) Iterator.State.Uninitialized);
-                                       ig.Emit (OpCodes.Call, TypeManager.int_interlocked_compare_exchange);
+                                       ig.Emit (OpCodes.Ldflda, host.PC.Spec.MetaInfo);
+                                       IntConstant.EmitInt (ig, (int) Iterator.State.Start);
+                                       IntConstant.EmitInt (ig, (int) Iterator.State.Uninitialized);
+                                       ig.Emit (OpCodes.Call, (MethodInfo) TypeManager.int_interlocked_compare_exchange.MetaInfo);
 
-                                       ig.Emit (OpCodes.Ldc_I4, (int) Iterator.State.Uninitialized);
-                                       ig.Emit (OpCodes.Bne_Un, label_init);
+                                       IntConstant.EmitInt (ig, (int) Iterator.State.Uninitialized);
+                                       ig.Emit (OpCodes.Bne_Un_S, label_init);
 
                                        ig.Emit (OpCodes.Ldarg_0);
                                        ig.Emit (OpCodes.Ret);
 
                                        ig.MarkLabel (label_init);
 
-                                       cast.Emit (ec);
+                                       new_storey.Emit (ec);
                                        ig.Emit (OpCodes.Ret);
                                }
 
@@ -437,46 +295,17 @@ namespace Mono.CSharp {
                                        throw new NotSupportedException ();
                                }
                        }
-               }
-
-               protected class DisposeMethod : Method
-               {
-                       readonly IteratorStorey Host;
 
-                       public DisposeMethod (IteratorStorey host)
-                               : base (host, null, TypeManager.system_void_expr,
-                                       Modifiers.PUBLIC | Modifiers.DEBUGGER_HIDDEN | Modifiers.COMPILER_GENERATED,
-                                       false, new MemberName ("Dispose", host.Location),
-                                       Parameters.EmptyReadOnlyParameters, null)
+                       public GetEnumeratorMethod (IteratorStorey host, FullNamedExpression returnType, MemberName name)
+                               : base (host, returnType, 0, name)
                        {
-                               this.Host = host;
-
-                               host.AddMethod (this);
-
-                               Block = new ToplevelBlock (host.Iterator.Container, null, Location);
-                               Block.AddStatement (new DisposeMethodStatement (Host.Iterator));
-
-                               Report.Debug (64, "DISPOSE METHOD", host, Block);
+                               Block.AddStatement (new GetEnumeratorStatement (host, this));
                        }
+               }
 
-                       public override EmitContext CreateEmitContext (DeclSpace tc, ILGenerator ig)
-                       {
-                               EmitContext ec = new EmitContext (
-                                       this, tc, this.ds, Location, ig, MemberType, ModFlags, false);
-
-                               ec.CurrentAnonymousMethod = Host.Iterator;
-                               return ec;
-                       }
-
-                       //public override void Emit ()
-                       //{
-                       //    if (Parent.MemberName.IsGeneric)
-                       //        block.MutateHoistedGenericType (Host.Iterator.Storey);
-
-                       //    base.Emit ();
-                       //}
-
-                       protected class DisposeMethodStatement : Statement
+               class DisposeMethod : IteratorMethod
+               {
+                       sealed class DisposeMethodStatement : Statement
                        {
                                Iterator iterator;
 
@@ -486,7 +315,12 @@ namespace Mono.CSharp {
                                        this.loc = iterator.Location;
                                }
 
-                               public override bool Resolve (EmitContext ec)
+                               protected override void CloneTo (CloneContext clonectx, Statement target)
+                               {
+                                       throw new NotSupportedException ();
+                               }
+
+                               public override bool Resolve (BlockContext ec)
                                {
                                        return true;
                                }
@@ -501,42 +335,240 @@ namespace Mono.CSharp {
                                        throw new NotSupportedException ();
                                }
                        }
+
+                       public DisposeMethod (IteratorStorey host)
+                               : base (host, TypeManager.system_void_expr, Modifiers.PUBLIC, new MemberName ("Dispose", host.Location))
+                       {
+                               host.AddMethod (this);
+
+                               Block = new ToplevelBlock (Compiler, host.Iterator.Container, ParametersCompiled.EmptyReadOnlyParameters, Location);
+                               Block.AddStatement (new DisposeMethodStatement (host.Iterator));
+                       }
                }
 
-               protected class CurrentBlock : Statement {
-                       IteratorStorey host;
-                       bool is_generic;
+               //
+               // Uses Method as method info
+               //
+               class DynamicMethodGroupExpr : MethodGroupExpr
+               {
+                       readonly Method method;
 
-                       public CurrentBlock (IteratorStorey host, bool is_generic)
+                       public DynamicMethodGroupExpr (Method method, Location loc)
+                               : base (null, loc)
                        {
-                               this.host = host;
-                               this.is_generic = is_generic;
-                               loc = host.Location;
+                               this.method = method;
+                               eclass = ExprClass.Unresolved;
                        }
 
-                       public override bool Resolve (EmitContext ec)
+                       protected override Expression DoResolve (ResolveContext ec)
                        {
-                               // We emit a 'ret', so prevent the enclosing TopLevelBlock from emitting one too
-                               ec.CurrentBranching.CurrentUsageVector.Goto ();
-                               return true;
+                               Methods = new [] { method.Spec };
+                               type = method.Parent.TypeBuilder;
+                               InstanceExpression = new CompilerGeneratedThis (type, Location);
+                               return base.DoResolve (ec);
                        }
+               }
 
-                       protected override void DoEmit (EmitContext ec)
-                       {
-                               ILGenerator ig = ec.ig;
+               class DynamicFieldExpr : FieldExpr
+               {
+                       readonly Field field;
 
-                               ig.Emit (OpCodes.Ldarg_0);
-                               ig.Emit (OpCodes.Ldfld, host.CurrentField.FieldBuilder);
-                               if (!is_generic)
-                                       ig.Emit (OpCodes.Box, host.CurrentField.MemberType);
-                               ig.Emit (OpCodes.Ret);
+                       public DynamicFieldExpr (Field field, Location loc)
+                               : base (loc)
+                       {
+                               this.field = field;
                        }
 
-                       public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
+                       protected override Expression DoResolve (ResolveContext ec)
                        {
-                               throw new NotSupportedException ();
+                               spec = field.Spec;
+                               type = TypeManager.TypeToCoreType (spec.FieldType);
+                               InstanceExpression = new CompilerGeneratedThis (type, Location);
+                               return base.DoResolve (ec);
                        }
                }
+
+               public readonly Iterator Iterator;
+
+               TypeExpr iterator_type_expr;
+               Field pc_field;
+               Field current_field;
+
+               TypeExpr enumerator_type;
+               TypeExpr enumerable_type;
+               TypeArguments generic_args;
+               TypeExpr generic_enumerator_type;
+               TypeExpr generic_enumerable_type;
+
+               List<HoistedParameter> hoisted_params_copy;
+               int local_name_idx;
+
+               public IteratorStorey (Iterator iterator)
+                       : base (iterator.Container.Toplevel, iterator.Host,
+                         iterator.OriginalMethod as MemberBase, iterator.GenericMethod, "Iterator")
+               {
+                       this.Iterator = iterator;
+               }
+
+               public Field PC {
+                       get { return pc_field; }
+               }
+
+               public Field CurrentField {
+                       get { return current_field; }
+               }
+
+               public IList<HoistedParameter> HoistedParameters {
+                       get { return hoisted_params; }
+               }
+
+               protected override TypeExpr [] ResolveBaseTypes (out TypeExpr base_class)
+               {
+                       iterator_type_expr = new TypeExpression (MutateType (Iterator.OriginalIteratorType), Location);
+                       generic_args = new TypeArguments (iterator_type_expr);
+
+                       var list = new List<FullNamedExpression> ();
+                       if (Iterator.IsEnumerable) {
+                               enumerable_type = new TypeExpression (
+                                       TypeManager.ienumerable_type, Location);
+                               list.Add (enumerable_type);
+
+                               if (TypeManager.generic_ienumerable_type != null) {
+                                       generic_enumerable_type = new GenericTypeExpr (
+                                               TypeManager.generic_ienumerable_type,
+                                               generic_args, Location);
+                                       list.Add (generic_enumerable_type);
+                               }
+                       }
+
+                       enumerator_type = new TypeExpression (
+                               TypeManager.ienumerator_type, Location);
+                       list.Add (enumerator_type);
+
+                       list.Add (new TypeExpression (TypeManager.idisposable_type, Location));
+
+                       if (TypeManager.generic_ienumerator_type != null) {
+                               generic_enumerator_type = new GenericTypeExpr (
+                                       TypeManager.generic_ienumerator_type,
+                                       generic_args, Location);
+                               list.Add (generic_enumerator_type);
+                       }
+
+                       type_bases = list;
+
+                       return base.ResolveBaseTypes (out base_class);
+               }
+
+               protected override string GetVariableMangledName (LocalInfo local_info)
+               {
+                       return "<" + local_info.Name + ">__" + local_name_idx++.ToString ();
+               }
+
+               public void DefineIteratorMembers ()
+               {
+                       pc_field = AddCompilerGeneratedField ("$PC", TypeManager.system_int32_expr);
+                       current_field = AddCompilerGeneratedField ("$current", iterator_type_expr);
+
+                       if (hoisted_params != null) {
+                               //
+                               // Iterators are independent, each GetEnumerator call has to
+                               // create same enumerator therefore we have to keep original values
+                               // around for re-initialization
+                               //
+                               // TODO: Do it for assigned/modified parameters only
+                               //
+                               hoisted_params_copy = new List<HoistedParameter> (hoisted_params.Count);
+                               foreach (HoistedParameter hp in hoisted_params) {
+                                       hoisted_params_copy.Add (new HoistedParameter (hp, "<$>" + hp.Field.Name));
+                               }
+                       }
+
+                       if (generic_enumerator_type != null)
+                               Define_Current (true);
+
+                       Define_Current (false);
+                       new DisposeMethod (this);
+                       Define_Reset ();
+
+                       if (Iterator.IsEnumerable) {
+                               MemberName name = new MemberName (QualifiedAliasMember.GlobalAlias, "System", null, Location);
+                               name = new MemberName (name, "Collections", Location);
+                               name = new MemberName (name, "IEnumerable", Location);
+                               name = new MemberName (name, "GetEnumerator", Location);
+
+                               if (generic_enumerator_type != null) {
+                                       Method get_enumerator = new IteratorMethod (this, enumerator_type, 0, name);
+
+                                       name = new MemberName (name.Left.Left, "Generic", Location);
+                                       name = new MemberName (name, "IEnumerable", generic_args, Location);
+                                       name = new MemberName (name, "GetEnumerator", Location);
+                                       Method gget_enumerator = new GetEnumeratorMethod (this, generic_enumerator_type, name);
+
+                                       //
+                                       // Just call generic GetEnumerator implementation
+                                       //
+                                       get_enumerator.Block.AddStatement (
+                                               new Return (new Invocation (new DynamicMethodGroupExpr (gget_enumerator, Location), null), Location));
+
+                                       AddMethod (get_enumerator);
+                                       AddMethod (gget_enumerator);
+                               } else {
+                                       AddMethod (new GetEnumeratorMethod (this, enumerator_type, name));
+                               }
+                       }
+               }
+
+               protected override void EmitHoistedParameters (EmitContext ec, IList<HoistedParameter> hoisted)
+               {
+                       base.EmitHoistedParameters (ec, hoisted);
+                       base.EmitHoistedParameters (ec, hoisted_params_copy);
+               }
+
+               void Define_Current (bool is_generic)
+               {
+                       TypeExpr type;
+
+                       MemberName name = new MemberName (QualifiedAliasMember.GlobalAlias, "System", null, Location);
+                       name = new MemberName (name, "Collections", Location);
+
+                       if (is_generic) {
+                               name = new MemberName (name, "Generic", Location);
+                               name = new MemberName (name, "IEnumerator", generic_args, Location);
+                               type = iterator_type_expr;
+                       } else {
+                               name = new MemberName (name, "IEnumerator");
+                               type = TypeManager.system_object_expr;
+                       }
+
+                       name = new MemberName (name, "Current", Location);
+
+                       ToplevelBlock get_block = new ToplevelBlock (Compiler, Location);
+                       get_block.AddStatement (new Return (new DynamicFieldExpr (CurrentField, Location), Location));
+                               
+                       Accessor getter = new Accessor (get_block, 0, null, null, Location);
+
+                       Property current = new Property (
+                               this, type, Modifiers.DEBUGGER_HIDDEN, name, null, getter, null, false);
+                       AddProperty (current);
+               }
+
+               void Define_Reset ()
+               {
+                       Method reset = new Method (
+                               this, null, TypeManager.system_void_expr,
+                               Modifiers.PUBLIC | Modifiers.DEBUGGER_HIDDEN,
+                               new MemberName ("Reset", Location),
+                               ParametersCompiled.EmptyReadOnlyParameters, null);
+                       AddMethod (reset);
+
+                       reset.Block = new ToplevelBlock (Compiler, Location);
+
+                       Type ex_type = TypeManager.CoreLookupType (Compiler, "System", "NotSupportedException", MemberKind.Class, true);
+                       if (ex_type == null)
+                               return;
+
+                       reset.Block.AddStatement (new Throw (new New (new TypeExpression (ex_type, Location), null, Location), Location));
+               }
        }
 
        //
@@ -544,8 +576,10 @@ namespace Mono.CSharp {
        //
        public class Iterator : AnonymousExpression {
                public readonly IMethodData OriginalMethod;
-
+               AnonymousMethodMethod method;
+               public readonly TypeContainer Host;
                public readonly bool IsEnumerable;
+               List<ResumableStatement> resume_points;
 
                //
                // The state as we generate the iterator
@@ -580,11 +614,6 @@ namespace Mono.CSharp {
                        Start = 0
                }
 
-               public override void AddStoreyReference (AnonymousMethodStorey storey)
-               {
-                       // do nothing
-               }
-
                public void EmitYieldBreak (ILGenerator ig, bool unwind_protect)
                {
                        ig.Emit (unwind_protect ? OpCodes.Leave : OpCodes.Br, move_next_error);
@@ -595,11 +624,11 @@ namespace Mono.CSharp {
                        ILGenerator ig = ec.ig;
 
                        ig.Emit (OpCodes.Ldarg_0);
-                       ig.Emit (OpCodes.Ldfld, IteratorHost.PC.FieldBuilder);
+                       ig.Emit (OpCodes.Ldfld, IteratorHost.PC.Spec.MetaInfo);
 
                        ig.Emit (OpCodes.Ldarg_0);
                        IntConstant.EmitInt (ig, (int) State.After);
-                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
+                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.Spec.MetaInfo);
 
                        // We only care if the PC is zero (start executing) or non-zero (don't do anything)
                        ig.Emit (OpCodes.Brtrue, move_next_error);
@@ -627,20 +656,20 @@ namespace Mono.CSharp {
 
                        current_pc = ec.GetTemporaryLocal (TypeManager.uint32_type);
                        ig.Emit (OpCodes.Ldarg_0);
-                       ig.Emit (OpCodes.Ldfld, IteratorHost.PC.FieldBuilder);
+                       ig.Emit (OpCodes.Ldfld, IteratorHost.PC.Spec.MetaInfo);
                        ig.Emit (OpCodes.Stloc, current_pc);
 
                        // 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);
+                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.Spec.MetaInfo);
 
                        Label [] labels = new Label [1 + resume_points.Count];
                        labels [0] = ig.DefineLabel ();
 
                        bool need_skip_finally = false;
                        for (int i = 0; i < resume_points.Count; ++i) {
-                               ResumableStatement s = (ResumableStatement) resume_points [i];
+                               ResumableStatement s = resume_points [i];
                                need_skip_finally |= s is ExceptionStatement;
                                labels [i+1] = s.PrepareForEmit (ec);
                        }
@@ -668,7 +697,7 @@ namespace Mono.CSharp {
 
                        ig.Emit (OpCodes.Ldarg_0);
                        IntConstant.EmitInt (ig, (int) State.After);
-                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
+                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.Spec.MetaInfo);
 
                        ig.MarkLabel (move_next_error);
                        ig.Emit (OpCodes.Ldc_I4_0);
@@ -705,13 +734,13 @@ namespace Mono.CSharp {
                        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.Ldfld, IteratorHost.PC.Spec.MetaInfo);
                                ig.Emit (OpCodes.Stloc, current_pc);
                        }
 
                        ig.Emit (OpCodes.Ldarg_0);
                        IntConstant.EmitInt (ig, (int) State.After);
-                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
+                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.Spec.MetaInfo);
 
                        if (labels != null) {
                                //SymbolWriter.StartIteratorDispatcher (ec.ig);
@@ -726,12 +755,11 @@ namespace Mono.CSharp {
                        ig.MarkLabel (end);
                }
 
-
-               ArrayList resume_points;
-               public int AddResumePoint (ResumableStatement stmt, Location loc)
+               public int AddResumePoint (ResumableStatement stmt)
                {
                        if (resume_points == null)
-                               resume_points = new ArrayList ();
+                               resume_points = new List<ResumableStatement> ();
+
                        resume_points.Add (stmt);
                        return resume_points.Count;
                }
@@ -746,12 +774,12 @@ namespace Mono.CSharp {
                        // Store the new current
                        ig.Emit (OpCodes.Ldarg_0);
                        expr.Emit (ec);
-                       ig.Emit (OpCodes.Stfld, IteratorHost.CurrentField.FieldBuilder);
+                       ig.Emit (OpCodes.Stfld, IteratorHost.CurrentField.Spec.MetaInfo);
 
                        // store resume program-counter
                        ig.Emit (OpCodes.Ldarg_0);
                        IntConstant.EmitInt (ig, resume_pc);
-                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.FieldBuilder);
+                       ig.Emit (OpCodes.Stfld, IteratorHost.PC.Spec.MetaInfo);
 
                        // mark finally blocks as disabled
                        if (unwind_protect && skip_finally != null) {
@@ -780,15 +808,17 @@ namespace Mono.CSharp {
                //
                // Our constructor
                //
-               private Iterator (IMethodData method, DeclSpace host, Type iterator_type, bool is_enumerable)
-                       : base (host,
-                               new ToplevelBlock (method.Block, Parameters.EmptyReadOnlyParameters, method.Block.StartLocation),
+               private Iterator (CompilerContext ctx, IMethodData method, TypeContainer host, Type iterator_type, bool is_enumerable)
+                       : base (
+                               new ToplevelBlock (ctx, method.Block, ParametersCompiled.EmptyReadOnlyParameters, method.Block.StartLocation),
                                TypeManager.bool_type,
                                method.Location)
                {
                        this.OriginalMethod = method;
                        this.OriginalIteratorType = iterator_type;
                        this.IsEnumerable = is_enumerable;
+                       this.Host = host;
+                       this.type = method.ReturnType;
 
                        IteratorHost = Block.ChangeToIterator (this, method.Block);
                }
@@ -798,21 +828,20 @@ namespace Mono.CSharp {
                        return OriginalMethod.GetSignatureForError ();
                }
 
-               public override Expression DoResolve (EmitContext ec)
+               protected override Expression DoResolve (ResolveContext ec)
                {
                        method = new AnonymousMethodMethod (Storey,
                                this, Storey, null, TypeManager.system_boolean_expr,
                                Modifiers.PUBLIC, OriginalMethod.GetSignatureForError (),
                                new MemberName ("MoveNext", Location),
-                               Parameters.EmptyReadOnlyParameters);
+                               ParametersCompiled.EmptyReadOnlyParameters);
 
-                       if (!Compatible (ec))
+                       if (Compatible (ec) == null)
                                return null;
 
                        IteratorHost.DefineIteratorMembers ();
 
                        eclass = ExprClass.Value;
-                       type = ec.ReturnType;
                        return this;
                }
 
@@ -831,21 +860,20 @@ namespace Mono.CSharp {
                                ig.Emit (OpCodes.Dup);
                                IntConstant.EmitInt (ig, (int)State.Uninitialized);
 
-                               FieldInfo field = IteratorHost.PC.FieldBuilder;
-#if GMCS_SOURCE
+                               FieldInfo field = IteratorHost.PC.Spec.MetaInfo;
                                if (Storey.MemberName.IsGeneric)
                                        field = TypeBuilder.GetField (Storey.Instance.Type, field);
-#endif
+
                                ig.Emit (OpCodes.Stfld, field);
                        }
                }
 
-               public override Expression CreateExpressionTree (EmitContext ec)
+               public override Expression CreateExpressionTree (ResolveContext ec)
                {
                        throw new NotSupportedException ("ET");
                }
 
-               public static void CreateIterator (IMethodData method, DeclSpace parent, int modifiers)
+               public static void CreateIterator (IMethodData method, TypeContainer parent, Modifiers modifiers, CompilerContext ctx)
                {
                        bool is_enumerable;
                        Type iterator_type;
@@ -855,7 +883,7 @@ namespace Mono.CSharp {
                                return;
 
                        if (!CheckType (ret, out iterator_type, out is_enumerable)) {
-                               Report.Error (1624, method.Location,
+                               ctx.Report.Error (1624, method.Location,
                                              "The body of `{0}' cannot be an iterator block " +
                                              "because `{1}' is not an iterator interface type",
                                              method.GetSignatureForError (),
@@ -863,24 +891,24 @@ namespace Mono.CSharp {
                                return;
                        }
 
-                       Parameters parameters = method.ParameterInfo;
+                       ParametersCompiled parameters = method.ParameterInfo;
                        for (int i = 0; i < parameters.Count; i++) {
                                Parameter p = parameters [i];
                                Parameter.Modifier mod = p.ModFlags;
                                if ((mod & Parameter.Modifier.ISBYREF) != 0) {
-                                       Report.Error (1623, p.Location,
+                                       ctx.Report.Error (1623, p.Location,
                                                "Iterators cannot have ref or out parameters");
                                        return;
                                }
 
-                               if ((mod & Parameter.Modifier.ARGLIST) != 0) {
-                                       Report.Error (1636, method.Location,
+                               if (p is ArglistParameter) {
+                                       ctx.Report.Error (1636, method.Location,
                                                "__arglist is not allowed in parameter list of iterators");
                                        return;
                                }
 
-                               if (p.ParameterType.IsPointer) {
-                                       Report.Error (1637, p.Location,
+                               if (parameters.Types [i].IsPointer) {
+                                       ctx.Report.Error (1637, p.Location,
                                                          "Iterators cannot have unsafe parameters or " +
                                                          "yield types");
                                        return;
@@ -888,11 +916,11 @@ namespace Mono.CSharp {
                        }
 
                        if ((modifiers & Modifiers.UNSAFE) != 0) {
-                               Report.Error (1629, method.Location, "Unsafe code may not appear in iterators");
+                               ctx.Report.Error (1629, method.Location, "Unsafe code may not appear in iterators");
                                return;
                        }
 
-                       Iterator iter = new Iterator (method, parent, iterator_type, is_enumerable);
+                       Iterator iter = new Iterator (ctx, method, parent, iterator_type, is_enumerable);
                        iter.Storey.DefineType ();
                }
 
@@ -921,13 +949,13 @@ namespace Mono.CSharp {
 
                        Type gt = TypeManager.DropGenericTypeArguments (ret);
                        if (gt == TypeManager.generic_ienumerable_type) {
-                               original_iterator_type = args [0];
+                               original_iterator_type = TypeManager.TypeToCoreType (args [0]);
                                is_enumerable = true;
                                return true;
                        }
                        
                        if (gt == TypeManager.generic_ienumerator_type) {
-                               original_iterator_type = args [0];
+                               original_iterator_type = TypeManager.TypeToCoreType (args [0]);
                                is_enumerable = false;
                                return true;
                        }