Re: Newbie back again...

[David Chisnall]

On 19 Jun 2017, at 23:43, Josh Freeman <address@hidden> wrote:
> 
>   The segmentation fault happens after Base sets the value of an NSThread 
> ivar, because the memory location it writes to overlaps the area in memory 
> where GUI expects to find a different ivar, due to the mismatched layouts; 
> When GUI reads its ivar, it finds a nonzero value (garbage), and when the 
> garbage value is sent an objc message, it crashes.

This sounds like a compiler bug.  The ivar accesses should both be using the 
same offset variable.  Are you sure that both are being compiled with the same 
ABI?  If so, would it be possible for you to compile the relevant -gui file and 
NSThread.m with -S (produce assembly, don’t compile) and send me the resulting 
output?

David