Can OpCodes.Jmp be called to transfer control to a method that resides on a different assembly? [closed]

Question

Can Method1 that resides in AssemblyA issue a OpCodes.Jmp to Method1 that resides in AssemblyB? Both methods have same exact signature.

I can't seem to make this work, always getting System.InvalidProgramException : Common Language Runtime detected an invalid program.

If the redirection is inside the same Assembly, it works.

If possible, please provide example using Reflection.Emit.

Answer 1

You must have missed something. Are both methods static? Do they have the same calling convention?

The following code doesn't reproduce your issue:

static void Main(string[] args)
{
    var assembly = AppDomain.CurrentDomain.DefineDynamicAssembly
                    (new AssemblyName("TestAssembly"), AssemblyBuilderAccess.Run);
    var module = assembly.DefineDynamicModule("Main");
    var type = module.DefineType("Test");

    var method = type.DefineMethod
                  (
                    "Test", MethodAttributes.Public | MethodAttributes.Static, 
                    typeof(int), new[] { typeof(string) }
                  );
    var gen = method.GetILGenerator();
    gen.Emit(OpCodes.Jmp, typeof(Class1).GetMethod("Test"));

    var obj = Activator.CreateInstance(type.CreateType());

    var func = (Func<string, int>)
                obj.GetType().GetMethod("Test").CreateDelegate(typeof(Func<string, int>));
    var result = func("Banana");

    Console.WriteLine(result);
    Console.ReadLine();
}

And in a different assembly, the Test class:

public static class Class1
{
    public static int Test(string hi)
    {
        return 42;
    }
}

Did you make sure you're not violating any of the restrictions?

• The evaluation stack must be empty when this instruction is executed.
• The calling convention, number and type of arguments at the destination address must match that of the current method.
• The jmp instruction cannot be used to transferred control out of a try, filter, catch, or finally block.