Re: Mysterious crash in NSRunLoop, using libobjc2 on Linux

[Lobron, David]

>> I did this, and I've pasted the output below.  At first glance, the 
>> exceptions all seem to be the same (or at least, all have the same address 
>> of 0x17158c80).  I'm not entirely sure how to interpret the rest of the 
>> action there.  One thing that leaps out is that there seem to be 
>> personalities involved: GNUCOBJC and GNUCC++.  The code that throws this 
>> exception is a .mm file, i.e., Objective-C++, with a mix of ObjC and C++.  
> 
> Aha!  That might be it, and might be enough to come up with a reduced test 
> case.  When you throw the exception, it’s an ObjC exception.  When you throw 
> it through an ObjC++ stack frame, it’s transformed into a C++ exception and 
> passed to the C++ personality function, but only when the cleanup is run for 
> that frame.  I suspect that the ObjC personality function is not correctly 
> handling the transformation back to an ObjC exception for the catch.

Thanks, David!  I will try to make a reduced test case, based on this.  I'll 
start with a simple program that throws an ObjC exception in an NS_HANDLER, 
where the whole thing resides in a .mm file.  BTW, I've enabled native 
exceptions here.  I will let you guys know when I've got something.

Thank you again for your help,

David