Re: Enabling compiler warning flags

[Eric Blake]

On 02/25/2013 06:09 PM, Jeffrey Walton wrote:

> GCC 4.8 added a couple of interesting flags
> (http://gcc.gnu.org/gcc-4.8/changes.html): -fsanitize=address and
> -fsanitize=thread. Some reading about them is available at
> http://llvm.org/devmtg/2012-11/Serebryany_TSan-MSan.pdf.
> 
> It might be helpful to projects if the auto tools enabled one or both
> by default. The overhead on Address Sanitizer looks small compared to
> the payoff.

That paper said address sanitizer added 2x slowdown (20x under
valgrind), and would need hardware support to cut the slowdown to only
20%.  It also said thread sanitizer added 20x to 300x slowdown.  That
sounds like neither one should be enabled by default, but are best used
during development.  But thanks for pointing them out - they sound
interesting.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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