On 5/19/19 10:06 PM, Marek Polacek wrote:
> On Sun, May 19, 2019 at 01:00:45PM -0700, Andrew Pinski wrote:
>> On Sun, May 19, 2019 at 12:54 PM Segher Boessenkool
>> <seg...@kernel.crashing.org> wrote:
>>>
>>> On Sun, May 19, 2019 at 03:21:01PM -0400, Marek Polacek wrote:
>>>> On Sun, May 19, 2019 at 03:11:08AM -0500, Segher Boessenkool wrote:
>>>>> On Sun, May 19, 2019 at 09:35:45AM +0200, Martin Liška wrote:
>>>>>> Do we really need a commit integer numbers after the transition? I know
>>>>>> we're used to it.
>>>>>> But git commit hash provides that same.
>>>>>
>>>>> Revision numbers are nice short text strings, and from a revision number
>>>>> you can see approximately when it happened, and from two revision numbers
>>>>> on the same branch you can trivially tell which one is older. Those are
>>>>> nice features. But we can live without it, IMO.
>>>>
>>>> Since I do many bisections a day, losing this capability would be Very Bad.
>>>> Without it, there's no range, and without a range, there's nothing to
>>>> _bisect_.
>>>>
>>>> I bisect by hand, so if I have cc1plus.250000 (good) and cc1plus.260000
>>>> (bad),
>>>> I know the commit I'm looking for is within that range, and I can easily
>>>> split
>>>> the range, and it's at most log n steps. Whereas if we had e.g.
>>>> cc1plus.de28b0
>>>> and cc1plus.a9bd4d, I couldn't do it anymore.
>>>
>>> Git can bisect automatically just fine, there is no upside to doing things
>>> manually. In git there are various handy ways of referring to commits; you
>>> can say master@{3 days ago} for example, or zut@{31} to get the 31st
>>> commit back on branch "zut", etc. See "man gitrevisions".
>>
>> Well one thing is if you have prebuilt cc1/cc1plus. So it is not
>> really doing a manual bisect per-say but rather it is doing a manual
>> bisect using prebuilt binaries and knowing which one comes before
>> which one.
>
> Exactly, we have many TBs of prebuilt binaries.
I combine both together, feel free to use my script:
https://github.com/marxin/script-misc/blob/master/gcc-bisect.py
It uses git repository for navigation, information about branches, tag releases
and so on. And then I have a folder with pre-built binaries which are identified
by commit hash. That works all fine.
Martin
>
>> One way is store the binaries based on the date that commit happened
>> instead. This is a bit more complex but still doable.
>
> Yeah, I guess we'll have to do something like that, then. :/
>
> --
> Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA
>
