System.ExecutionEngineException：尝试 JIT 编译方法 System.Threading.Interlocked:Exchange

Question

我知道，如果编译器认为没有使用方法，有时会忽略方法，您可以通过在代码中直接引用方法来强制编译器包含它来解决此问题。但是，在这种情况下，它似乎不起作用。

这是异常和调用堆栈：

System.ExecutionEngineException: Attempting to JIT compile method '(wrapper managed-to-native) System.Threading.Interlocked:Exchange (System.Threading.Tasks.IContinuation&,System.Threading.Tasks.IContinuation)' while running with --aot-only. See http://docs.xamarin.com/ios/about/limitations for more information.

at System.Threading.Tasks.TaskCompletionQueue`1[System.Threading.Tasks.IContinuation].TryGetNextCompletion (IContinuation& continuation) [0x00000] in <filename unknown>:0
at System.Threading.Tasks.Task.ProcessCompleteDelegates () [0x0001b] in /Developer/MonoTouch/Source/mono/mcs/class/corlib/System.Threading.Tasks/Task.cs:521
at System.Threading.Tasks.Task.HandleGenericException (System.AggregateException e) [0x0001a] in /Developer/MonoTouch/Source/mono/mcs/class/corlib/System.Threading.Tasks/Task.cs:563
at System.Threading.Tasks.Task.TrySetException (System.AggregateException aggregate) [0x0003e] in /Developer/MonoTouch/Source/mono/mcs/class/corlib/System.Threading.Tasks/Task.cs:440
at System.Threading.Tasks.TaskCompletionSource`1[System.Net.WebResponse].TrySetException (IEnumerable`1 exceptions) [0x00000] in <filename unknown>:0
at System.Threading.Tasks.TaskCompletionSource`1[System.Net.WebResponse].SetException (IEnumerable`1 exceptions) [0x00000] in <filename unknown>:0
at System.Threading.Tasks.TaskCompletionSource`1[System.Net.WebResponse].SetException (System.Exception exception) [0x00000] in <filename unknown>:0
at System.Threading.Tasks.TaskFactory`1[System.Net.WebResponse].InnerInvoke (System.Threading.Tasks.TaskCompletionSource`1 tcs, System.Func`2 endMethod, IAsyncResult l) [0x00000] in <filename unknown>:0
at System.Threading.Tasks.TaskFactory`1+<FromAsyncBeginEnd>c__AnonStorey21[System.Net.WebResponse].<>m__15 (IAsyncResult l) [0x00000] in <filename unknown>:0
at Vistian.Net.Http.HttpRequestProcessor+<BeginGetResponse>c__AnonStorey3.<>m__5 (IAsyncResult result) [0x00082] in /Users/martinstafford/Projects/Vistian/vistian/common/Vistian.Net/trunk/Vistian.Net.Portable/Http/HttpRequestProcessor.cs:441
at System.Net.WebAsyncResult.CB (System.Object unused) [0x00000] in /Developer/MonoTouch/Source/mono/mcs/class/System/System.Net/WebAsyncResult.cs:148

我已经尝试在有问题的类的构造函数中包含这一行，但错误仍然存​​在：

object dummy = System.Threading.Interlocked.Exchange( ref dummyLock, new object()); 

这是错误的代码。抱歉有这么多，但它在上下文中得到它。调用“回调”时抛出异常 - 其中任何一个。如您所见，我正在尝试为包含 GetRequestStream 和 GetResponse 这两个异步操作的类实现异步编程模型：

                    public static IAsyncResult BeginGetResponse(AsyncCallback callback, object state)
    {
        var requestProcessor = state as HttpRequestProcessor;

        // create the Uri of the Host and Path in the request
        // and use it to create a HttpWebRequest
        Uri u = new Uri(new Uri(requestProcessor.Request.Host), requestProcessor.Request.Path);
        requestProcessor.HttpWebRequest = WebRequest.Create(u) as HttpWebRequest;

        // set up the header of the HttpWebRequest
        requestProcessor.SetupHeader(requestProcessor.HttpWebRequest, requestProcessor.Request);

        requestProcessor.WebResponse = null;
        requestProcessor.RaisedException = null;

        // set up an event to be used to 'timeout' the forthcoming async process
        var syncRef = new System.Threading.AutoResetEvent(false);

        System.Diagnostics.Debug.WriteLine(string.Format("HttpRequestProcessor.BeginGetResponse: started method={0}", requestProcessor.Request.Method));

        // perform the request using the Async method
        // GET and POST requests are processed differently
        if (requestProcessor.Request.Method == HttpMethod.POST)
        {
            // create the request content using the serialiser
            var bytes = requestProcessor.Encoder.Encode(requestProcessor.Request.Data, requestProcessor.Request.ContentType);

            System.Diagnostics.Debug.WriteLine("HttpRequestProcessor.BeginGetResponse: BeginGetRequestStream started");

            // start the async process by adding the content to the request
            requestProcessor.HttpWebRequest.BeginGetRequestStream((IAsyncResult result) =>
            {
                // the asyncronous Get RequestStream has finished in some way
                // complete the Get RequestStream process by calling EndGetRequestStream

                // get the HttpWebRequest provided in the 'state' parameter and
                // use it to call EndGetRequestStream
                var request = result.AsyncState as HttpWebRequest;
                try
                {
                    // fill the request stream with the content
                    using (Stream requestStream = request.EndGetRequestStream(result))
                    {
                        requestStream.Write(bytes, 0, bytes.Length);
                    }

                    System.Diagnostics.Debug.WriteLine("HttpRequestProcessor.BeginGetResponse: EndGetRequestStream");
                }
                catch (Exception e)
                {
                    // if the filling of the request stream fails, finish the Async process here
                    System.Diagnostics.Debug.WriteLine(string.Format("HttpRequestProcessor.BeginGetResponse: EndGetRequestSteam failed. Uri={0}", request.RequestUri));

                    // remember the exception, to be picked up by the subsequent call in to EndGetResponse
                    requestProcessor.RaisedException = e;

                    // clear the timeout event to indicate the async process has finished
                    syncRef.Set();

                    // call the callback as the async process is finished
                    callback(new AsyncResult(requestProcessor, true));

                    return;
                }

                System.Diagnostics.Debug.WriteLine("HttpRequestProcessor.BeginGetResponse: BeginGetResponse started");

                // the HttpWebRequest has the request content in it
                // send the request and get the response
                request.BeginGetResponse((IAsyncResult responseResult) =>
                {
                    // the Async process GetResponse has finished in some way
                    // get the HttpWebRequest provided as a parameter and use it
                    // to complete the GetRespone process

                    HttpWebRequest req = responseResult.AsyncState as HttpWebRequest;
                    try
                    {
                        requestProcessor.WebResponse = req.EndGetResponse(responseResult);
                        System.Diagnostics.Debug.WriteLine("HttpRequestProcessor.BeginGetResponse: EndGetResponse");
                    }
                    catch (Exception e)
                    {
                        // if getting the response fails, catch and remember the exception
                        // for the subsequent call in to EndGetResponse
                        System.Diagnostics.Debug.WriteLine(string.Format("HttpRequestProcessor.BeginGetResponse: EndGetResponse failed. Uri={0}", req.RequestUri));
                        requestProcessor.RaisedException = e;
                    }

                    // clear the timeout timer event
                    syncRef.Set();

                    // call the async callback 
                    callback(new AsyncResult(requestProcessor, true));

                    System.Diagnostics.Debug.WriteLine("HttpRequestProcessor.BeginGetResponse: POST callback complete");

                }, request);

            }, requestProcessor.HttpWebRequest);
        }
        else
        {
            requestProcessor.HttpWebRequest.BeginGetResponse((IAsyncResult responseResult) =>
            {
                HttpWebRequest req = responseResult.AsyncState as HttpWebRequest;

                try
                {
                    requestProcessor.WebResponse = req.EndGetResponse(responseResult);
                    System.Diagnostics.Debug.WriteLine("HttpRequestProcessor.BeginGetResponse: EndGetResponse");
                }
                catch (Exception e)
                {
                    System.Diagnostics.Debug.WriteLine(string.Format("HttpRequestProcessor.BeginGetResponse: EndGetResponse failed. Uri={0}", req.RequestUri));
                    requestProcessor.RaisedException = e;
                }

                syncRef.Set();

                callback(new AsyncResult(requestProcessor, true));

                System.Diagnostics.Debug.WriteLine("HttpRequestProcessor.BeginGetResponse: GET callback complete");

            }, requestProcessor.HttpWebRequest);
        }

        // wait for the async process to finish or timeout
        if (!syncRef.WaitOne(requestProcessor.Request.Timeout))
        {
            // async process has time out
            System.Diagnostics.Debug.WriteLine("HttpRequestProcessor.BeginGetResponse: BeginGetStreamRequest timed out");

            // abort the async process and create and remember an exception
            // to be picked up by the call in the EndGetResponse
            requestProcessor.HttpWebRequest.Abort();
            requestProcessor.RaisedException = new TimeoutException("loading request stream timed out");
        }

        return new AsyncResult(requestProcessor, false);
    }

    public static WebResponse EndGetResponse(IAsyncResult result)
    {
        System.Diagnostics.Debug.WriteLine("HttpRequestProcessor.EndGetResponse:");

        var requestProcessor = result.AsyncState as HttpRequestProcessor;

        if (requestProcessor.RaisedException != null)
        {
            throw requestProcessor.RaisedException;
        }
        return requestProcessor.WebResponse;
    }

Answer 1

将这个添加到构造函数中就可以了：

var dummy = System.Threading.Interlocked.Exchange(ref dummyTask, System.Threading.Tasks.Task.Factory.StartNew (() =>{}));