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Re: [PATCH] Memory fencing problem in pthread cancellation
On Wed, 16 Jan 2013, Rich Felker wrote:
> I've seen that the unwinder goes to great lengths (I would call it
> "hideous hacks") for stuff related to signal trampolines, and as far
> as I can tell, the only reason it would ever be needed is for
> unwinding out of signal handlers, which is DEEP in the realm of UB and
> not something I can see any justification for trying to support. Is
> there another reason the signal trampolines need special consideration
> that I'm not seeing?
Unwinding is not just about things defined at language level such as C++
exceptions (and thread cancellation). Accurate unwinding from signal
handlers can be used for other things such as profiling (see the Froyd et
al paper in the 2006 GCC Summit proceedings).
Joseph S. Myers