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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
joseph@codesourcery.com