Question

I have a strange problem where MonoTouch seems to be either not compiling methods or not able to find a compiled method it is instructed to call, and only on the device in the Release configuration – Debug builds are fine. I’ve tried reproducing it with a simpler code sample with no luck, so I doubt you will be able to see the behavior with the code below. But this is essentially what I’m doing:

using System;
using MonoTouch.UIKit;

public class MyClass
{
    private UINavigationController _navController;
    private UIViewControler _viewController;

    public UINavigationController NavController
    {
        get
        {
            if (_navController == null)
            {
                if (_viewController == null)
                {
                    _viewController = new UIViewController();
                }
                _navController = new UINavigationController(_viewController);
            }
            return _navController;
        }
    }
}

Then, in some other method…

public void SomeMethod()
{
    MyClass myClass = new MyClass();
    var navController = myClass.NavController; // <-- This is where it throws
}

The exception I get is the standard JIT compile message, saying that it attempted to JIT get_NavController(). I find this very strange, because there’s no virtual generics, no LINQ, the linker is off, and nothing else that normally causes JITs seems to be involved. I’ve also verified that it will throw for other methods and properties defined on MyClass, but not the constructor or System.Object inherited methods. Reflection reveals that myClass.GetType().GetMembers() has a MemberInfo for everything I would expect. Yet, only for Release|iPhone, I can’t access these methods or properties. The only logical conclusion I can come to is that the aot compilation step is missing them, and I don’t know why that would happen at all, let alone only in the Release configuration.

My question is, what could be causing such a situation, and what is the next step to fixing it? I’m not even sure where to go from here on debugging this, or what to file a bug about, because I can’t reproduce it out of the context of our (much) larger project.

Update: The exact exception text was requested.

System.ExecutionException: Attempting to JIT compile method
'MyNamespace.MyClass.get_NavController ()' while running with --aot-only

Answer 1

This doesn’t look like something that can be solved here.

I suggest filing a bug, and attach the entire project if you’re unable to make a smaller test case. You can file private bugs only Xamarin employees have access to if you don’t want your project to be publicly visible.