public override void Emit(EmitContext ec) { Label is_null_label = ec.DefineLabel(); Label end_label = ec.DefineLabel(); unwrap.EmitCheck(ec); ec.Emit(OpCodes.Brfalse, is_null_label); if (user_operator != null) { user_operator.Emit(ec); } else { EmitOperator(ec, NullableInfo.GetUnderlyingType(type)); } ec.Emit(OpCodes.Newobj, NullableInfo.GetConstructor(type)); ec.Emit(OpCodes.Br_S, end_label); ec.MarkLabel(is_null_label); LiftedNull.Create(type, loc).Emit(ec); ec.MarkLabel(end_label); }
public override void Emit(EmitContext ec) { Label is_null_label = ec.DefineLabel(); Label end_label = ec.DefineLabel(); unwrap.EmitCheck(ec); ec.Emit(OpCodes.Brfalse, is_null_label); expr.Emit(ec); ec.Emit(OpCodes.Br, end_label); ec.MarkLabel(is_null_label); null_value.Emit(ec); ec.MarkLabel(end_label); }
public override void Emit(EmitContext ec) { Label end_label = ec.DefineLabel(); if (unwrap != null) { Label is_null_label = ec.DefineLabel(); unwrap.EmitCheck(ec); ec.Emit(OpCodes.Brfalse, is_null_label); // // When both expressions are nullable the unwrap // is needed only for null check not for value uwrap // if (type.IsNullableType && TypeSpecComparer.IsEqual(NullableInfo.GetUnderlyingType(type), unwrap.Type)) { unwrap.Load(ec); } else { left.Emit(ec); } ec.Emit(OpCodes.Br, end_label); ec.MarkLabel(is_null_label); right.Emit(ec); ec.MarkLabel(end_label); return; } // // Null check is done on original expression not after expression is converted to // result type. This is in most cases same but when user conversion is involved // we can end up in situation when use operator does the null handling which is // not what the operator is supposed to do // var op_expr = left as UserCast; if (op_expr != null) { op_expr.Source.Emit(ec); LocalTemporary temp; // TODO: More load kinds can be special cased if (!(op_expr.Source is VariableReference)) { temp = new LocalTemporary(op_expr.Source.Type); temp.Store(ec); temp.Emit(ec); op_expr.Source = temp; } else { temp = null; } var right_label = ec.DefineLabel(); ec.Emit(OpCodes.Brfalse_S, right_label); left.Emit(ec); ec.Emit(OpCodes.Br, end_label); ec.MarkLabel(right_label); if (temp != null) { temp.Release(ec); } } else { // // Common case where expression is not modified before null check and // we generate better/smaller code // left.Emit(ec); ec.Emit(OpCodes.Dup); // Only to make verifier happy if (left.Type.IsGenericParameter) { ec.Emit(OpCodes.Box, left.Type); } ec.Emit(OpCodes.Brtrue, end_label); ec.Emit(OpCodes.Pop); } right.Emit(ec); ec.MarkLabel(end_label); }