Re: [Qemu-devel] [PATCH v2 04/13] build-sys: add AddressSanitizer when --enable-debug if possible

[Paolo Bonzini <pbonzini@redhat.com>]

On 03/01/2018 19:02, Marc-André Lureau wrote:
> Hi
> 
> On Wed, Jan 3, 2018 at 6:52 PM, Peter Maydell <peter.maydell@linaro.org> wrote:
>> On 2 January 2018 at 17:31, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>> 2) I think removing -O2 from --enable-debug should be removed at the
>>> same time.  That pretty much guarantees that nobody will use
>>> --enable-debug, and optimized builds are decently debuggable nowadays.
>>> The best would be to detect -Og, and add either -Og or -O1 depending on
>>> presence.
>>
>> Hmm. I use --enable-debug all the time and one of the reasons
>> I use it is that the optimized build is usually more pain
>> to debug with...
> 
>        -Og Optimize debugging experience.  -Og enables optimizations
> that do not interfere with debugging. It should be the optimization
> level of choice for the standard edit-compile-debug cycle, offering
>            a reasonable level of optimization while maintaining fast
> compilation and a good debugging experience.
> 
> That should cover debugging nicely. Tbh, I am quite happy with
> compiler default to O0 when --enable-debug. Og doesn't give me much
> different experience.
> 
> However, it produces false-positive warnings with gcc.

-O0 doesn't enable those warnings at all, because it would have even
more false positives. :)

Paolo