public void EmitPrologue(EmitContext ec) { awaiter = ((AsyncTaskStorey)machine_initializer.Storey).AddAwaiter(expr.Type, loc); var fe_awaiter = new FieldExpr(awaiter, loc); fe_awaiter.InstanceExpression = new CompilerGeneratedThis(ec.CurrentType, loc); // // awaiter = expr.GetAwaiter (); // using (ec.With(BuilderContext.Options.OmitDebugInfo, true)) { fe_awaiter.EmitAssign(ec, expr, false, false); } Label skip_continuation = ec.DefineLabel(); Expression completed_expr; if (IsDynamic) { var rc = new ResolveContext(ec.MemberContext); Arguments dargs = new Arguments(1); dargs.Add(new Argument(fe_awaiter)); completed_expr = new DynamicMemberBinder("IsCompleted", dargs, loc).Resolve(rc); dargs = new Arguments(1); dargs.Add(new Argument(completed_expr)); completed_expr = new DynamicConversion(ec.Module.Compiler.BuiltinTypes.Bool, 0, dargs, loc).Resolve(rc); } else { var pe = PropertyExpr.CreatePredefined(awaiter_definition.IsCompleted, loc); pe.InstanceExpression = fe_awaiter; completed_expr = pe; } completed_expr.EmitBranchable(ec, skip_continuation, true); base.DoEmit(ec); // // The stack has to be empty before calling await continuation. We handle this // by lifting values which would be left on stack into class fields. The process // is quite complicated and quite hard to test because any expression can possibly // leave a value on the stack. // // Following assert fails when some of expression called before is missing EmitToField // or parent expression fails to find await in children expressions // ec.AssertEmptyStack(); var storey = (AsyncTaskStorey)machine_initializer.Storey; if (IsDynamic) { storey.EmitAwaitOnCompletedDynamic(ec, fe_awaiter); } else { storey.EmitAwaitOnCompleted(ec, fe_awaiter); } // Return ok machine_initializer.EmitLeave(ec, unwind_protect); ec.MarkLabel(resume_point); ec.MarkLabel(skip_continuation); }
public override void Emit (EmitContext ec) { // // Use same anonymous method implementation for scenarios where same // code is used from multiple blocks, e.g. field initializers // if (method == null) { // // Delay an anonymous method definition to avoid emitting unused code // for unreachable blocks or expression trees // method = DoCreateMethodHost (ec); method.Define (); } bool is_static = (method.ModFlags & Modifiers.STATIC) != 0; if (is_static && am_cache == null) { // // Creates a field cache to store delegate instance if it's not generic // if (!method.MemberName.IsGeneric) { var parent = method.Parent.PartialContainer; int id = parent.AnonymousMethodsCounter++; var cache_type = storey != null && storey.Mutator != null ? storey.Mutator.Mutate (type) : type; am_cache = new Field (parent, new TypeExpression (cache_type, loc), Modifiers.STATIC | Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED, new MemberName (CompilerGeneratedContainer.MakeName (null, "f", "am$cache", id), loc), null); am_cache.Define (); parent.AddField (am_cache); } else { // TODO: Implement caching of generated generic static methods // // Idea: // // Some extra class is needed to capture variable generic type // arguments. Maybe we could re-use anonymous types, with a unique // anonymous method id, but they are quite heavy. // // Consider : "() => typeof(T);" // // We need something like // static class Wrap<Tn, Tm, DelegateType> { // public static DelegateType cache; // } // // We then specialize local variable to capture all generic parameters // and delegate type, e.g. "Wrap<Ta, Tb, DelegateTypeInst> cache;" // } } Label l_initialized = ec.DefineLabel (); if (am_cache != null) { ec.Emit (OpCodes.Ldsfld, am_cache.Spec); ec.Emit (OpCodes.Brtrue_S, l_initialized); } // // Load method delegate implementation // if (is_static) { ec.EmitNull (); } else if (storey != null) { Expression e = storey.GetStoreyInstanceExpression (ec).Resolve (new ResolveContext (ec.MemberContext)); if (e != null) { e.Emit (ec); } } else { ec.EmitThis (); // // Special case for value type storey where this is not lifted but // droped off to parent class // for (var b = Block.Parent; b != null; b = b.Parent) { if (b.ParametersBlock.StateMachine != null) { ec.Emit (OpCodes.Ldfld, b.ParametersBlock.StateMachine.HoistedThis.Field.Spec); break; } } } var delegate_method = method.Spec; if (storey != null && storey.MemberName.IsGeneric) { TypeSpec t = storey.Instance.Type; // // Mutate anonymous method instance type if we are in nested // hoisted generic anonymous method storey // if (ec.IsAnonymousStoreyMutateRequired) { t = storey.Mutator.Mutate (t); } ec.Emit (OpCodes.Ldftn, TypeBuilder.GetMethod (t.GetMetaInfo (), (MethodInfo) delegate_method.GetMetaInfo ())); } else { if (delegate_method.IsGeneric) delegate_method = delegate_method.MakeGenericMethod (ec.MemberContext, method.TypeParameters); ec.Emit (OpCodes.Ldftn, delegate_method); } var constructor_method = Delegate.GetConstructor (type); ec.Emit (OpCodes.Newobj, constructor_method); if (am_cache != null) { ec.Emit (OpCodes.Stsfld, am_cache.Spec); ec.MarkLabel (l_initialized); ec.Emit (OpCodes.Ldsfld, am_cache.Spec); } }