Handle type hidding via local variables and parameters. Fixes #8383
[mono.git] / mcs / mcs / async.cs
index c539ce8da118c7cbd2d2c8ae6e605983ad703f79..6de09f01b1a9d83ff4a899f8cff922549a19e19d 100644 (file)
@@ -7,7 +7,7 @@
 // Dual licensed under the terms of the MIT X11 or GNU GPL
 //
 // Copyright 2011 Novell, Inc.
-// Copyright 2011 Xamarin Inc.
+// Copyright 2011-2012 Xamarin Inc.
 //
 
 using System;
@@ -16,8 +16,10 @@ using System.Linq;
 using System.Collections;
 
 #if STATIC
+using IKVM.Reflection;
 using IKVM.Reflection.Emit;
 #else
+using System.Reflection;
 using System.Reflection.Emit;
 #endif
 
@@ -40,6 +42,12 @@ namespace Mono.CSharp
                        }
                }
 
+               public AwaitStatement Statement {
+                       get {
+                               return stmt;
+                       }
+               }
+
                protected override void CloneTo (CloneContext clonectx, Expression target)
                {
                        var t = (Await) target;
@@ -113,7 +121,7 @@ namespace Mono.CSharp
                }
        }
 
-       class AwaitStatement : YieldStatement<AsyncInitializer>
+       public class AwaitStatement : YieldStatement<AsyncInitializer>
        {
                sealed class AwaitableMemberAccess : MemberAccess
                {
@@ -215,7 +223,9 @@ namespace Mono.CSharp
                        //
                        // awaiter = expr.GetAwaiter ();
                        //
-                       fe_awaiter.EmitAssign (ec, expr, false, false);
+                       using (ec.With (BuilderContext.Options.OmitDebugInfo, true)) {
+                               fe_awaiter.EmitAssign (ec, expr, false, false);
+                       }
 
                        Label skip_continuation = ec.DefineLabel ();
 
@@ -272,14 +282,8 @@ namespace Mono.CSharp
 
                        awaiter.IsAvailableForReuse = true;
 
-                       if (ResultType.Kind != MemberKind.Void) {
-                               var storey = (AsyncTaskStorey) machine_initializer.Storey;
-
-                           if (storey.HoistedReturn != null)
-                               storey.HoistedReturn.EmitAssign (ec);
-                               else
-                                       ec.Emit (OpCodes.Pop);
-                       }
+                       if (ResultType.Kind != MemberKind.Void)
+                               ec.Emit (OpCodes.Pop);
                }
 
                void Error_WrongAwaiterPattern (ResolveContext rc, TypeSpec awaiter)
@@ -399,12 +403,6 @@ namespace Mono.CSharp
                        }
                }
 
-               public Block OriginalBlock {
-                       get {
-                               return block.Parent;
-                       }
-               }
-
                public TypeInferenceContext ReturnTypeInference {
                        get {
                                return return_inference;
@@ -413,38 +411,6 @@ namespace Mono.CSharp
 
                #endregion
 
-               public static void Create (IMemberContext context, ParametersBlock block, ParametersCompiled parameters, TypeDefinition host, TypeSpec returnType, Location loc)
-               {
-                       for (int i = 0; i < parameters.Count; i++) {
-                               Parameter p = parameters[i];
-                               Parameter.Modifier mod = p.ModFlags;
-                               if ((mod & Parameter.Modifier.RefOutMask) != 0) {
-                                       host.Compiler.Report.Error (1988, p.Location,
-                                               "Async methods cannot have ref or out parameters");
-                                       return;
-                               }
-
-                               if (p is ArglistParameter) {
-                                       host.Compiler.Report.Error (4006, p.Location,
-                                               "__arglist is not allowed in parameter list of async methods");
-                                       return;
-                               }
-
-                               if (parameters.Types[i].IsPointer) {
-                                       host.Compiler.Report.Error (4005, p.Location,
-                                               "Async methods cannot have unsafe parameters");
-                                       return;
-                               }
-                       }
-
-                       if (!block.HasAwait) {
-                               host.Compiler.Report.Warning (1998, 1, loc,
-                                       "Async block lacks `await' operator and will run synchronously");
-                       }
-
-                       block.WrapIntoAsyncTask (context, host, returnType);
-               }
-
                protected override BlockContext CreateBlockContext (ResolveContext rc)
                {
                        var ctx = base.CreateBlockContext (rc);
@@ -495,8 +461,8 @@ namespace Mono.CSharp
                Dictionary<TypeSpec, List<Field>> stack_fields;
                Dictionary<TypeSpec, List<Field>> awaiter_fields;
 
-               public AsyncTaskStorey (IMemberContext context, AsyncInitializer initializer, TypeSpec type)
-                       : base (initializer.OriginalBlock, initializer.Host, context.CurrentMemberDefinition as MemberBase, context.CurrentTypeParameters, "async", MemberKind.Class)
+               public AsyncTaskStorey (ParametersBlock block, IMemberContext context, AsyncInitializer initializer, TypeSpec type)
+                       : base (block, initializer.Host, context.CurrentMemberDefinition as MemberBase, context.CurrentTypeParameters, "async", MemberKind.Struct)
                {
                        return_type = type;
                        awaiter_fields = new Dictionary<TypeSpec, List<Field>> ();
@@ -522,6 +488,12 @@ namespace Mono.CSharp
                        }
                }
 
+               protected override TypeAttributes TypeAttr {
+                       get {
+                               return base.TypeAttr & ~TypeAttributes.SequentialLayout;
+                       }
+               }
+
                #endregion
 
                public Field AddAwaiter (TypeSpec type, Location loc)
@@ -781,16 +753,10 @@ namespace Mono.CSharp
                                InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, Location)
                        };
 
-                       // TODO: CompilerGeneratedThis is enough for structs
-                       var temp_this = new LocalTemporary (CurrentType);
-                       temp_this.EmitAssign (ec, new CompilerGeneratedThis (CurrentType, Location), false, false);
-
                        var args = new Arguments (2);
                        args.Add (new Argument (awaiter, Argument.AType.Ref));
-                       args.Add (new Argument (temp_this, Argument.AType.Ref));
+                       args.Add (new Argument (new CompilerGeneratedThis (CurrentType, Location), Argument.AType.Ref));
                        mg.EmitCall (ec, args);
-
-                       temp_this.Release (ec);
                }
 
                public void EmitInitializer (EmitContext ec)
@@ -820,14 +786,14 @@ namespace Mono.CSharp
                        //
                        // stateMachine.$builder = AsyncTaskMethodBuilder<{task-type}>.Create();
                        //
-                       instance.Emit (ec); // .AddressOf (ec, AddressOp.Store);
+                       instance.AddressOf (ec, AddressOp.Store);
                        ec.Emit (OpCodes.Call, builder_factory);
                        ec.Emit (OpCodes.Stfld, builder_field);
 
                        //
                        // stateMachine.$builder.Start<{storey-type}>(ref stateMachine);
                        //
-                       instance.Emit (ec); //.AddressOf (ec, AddressOp.Store);
+                       instance.AddressOf (ec, AddressOp.Store);
                        ec.Emit (OpCodes.Ldflda, builder_field);
                        if (Task != null)
                                ec.Emit (OpCodes.Dup);
@@ -893,7 +859,7 @@ namespace Mono.CSharp
 
                protected override TypeSpec[] ResolveBaseTypes (out FullNamedExpression base_class)
                {
-                       base_type = Compiler.BuiltinTypes.Object; // ValueType;
+                       base_type = Compiler.BuiltinTypes.ValueType;
                        base_class = null;
 
                        var istate_machine = Module.PredefinedTypes.IAsyncStateMachine;
@@ -905,7 +871,7 @@ namespace Mono.CSharp
                }
        }
 
-       class StackFieldExpr : FieldExpr
+       class StackFieldExpr : FieldExpr, IExpressionCleanup
        {
                public StackFieldExpr (Field field)
                        : base (field, Location.Null)
@@ -928,6 +894,19 @@ namespace Mono.CSharp
 
                        var field = (Field) spec.MemberDefinition;
                        field.IsAvailableForReuse = true;
+
+                       //
+                       // Release any captured reference type stack variables
+                       // to imitate real stack behavour and help GC stuff early
+                       //
+                       if (TypeSpec.IsReferenceType (type)) {
+                               ec.AddStatementEpilog (this);
+                       }
+               }
+
+               void IExpressionCleanup.EmitCleanup (EmitContext ec)
+               {
+                       EmitAssign (ec, new NullConstant (type, loc), false, false);
                }
        }
 }