[webkit-dev] PSA: Bit fields won't be packed on Windows if you mix types

[Ryosuke Niwa]

On Thu, Sep 3, 2020 at 11:15 PM Fujii Hironori <fujii.hironori at gmail.com>
wrote:

>
> On Fri, Sep 4, 2020 at 2:56 PM Ryosuke Niwa <rniwa at webkit.org> wrote:
>
>> On Thu, Sep 3, 2020 at 10:11 PM Fujii Hironori <fujii.hironori at gmail.com>
>> wrote:
>>
>>>
>>> On Fri, Sep 4, 2020 at 1:31 PM Ryosuke Niwa <rniwa at webkit.org> wrote:
>>>
>>>> Consecutive bit fields must use the same type.
>>>>
>>>
>>> RenderLayer is mixing bool and unsigned in the consecutive bit fields.
>>> They should use only uint8_t, right?
>>>
>>> https://trac.webkit.org/browser/webkit/trunk/Source/WebCore/rendering/RenderLayer.h#L1263
>>>
>>
>> Under the proposed coding style guide, yes, although I highly doubt the
>> size of RenderLayer really matters.
>>
>>
> Do you mean your new rule is applicable only for performance
> critical parts?
>

No, I'm saying that applying the proposed guideline wouldn't necessarily
help memory usage cause RenderLayer is a really large object anyway.
It doesn't mean we shouldn't apply.

BTW, I don't like to idea adding a new rule, but keeping old
> style code. It introduces divergence between the guideline and
> actual code. Do we really need a new rule that one doesn't
> necessary have to follow?
>

We should follow the proposed guideline in new code but we typically don't
update existing code to match the new guideline when we introduce a new
coding style guideline.

- R. Niwa
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.webkit.org/pipermail/webkit-dev/attachments/20200904/01c2c49c/attachment.htm>