[Qt-creator] Clang Code Model: add -Wno-padded

[Andrzej Telszewski]

On 04/03/16 01:05, Bubke Marco wrote:
> Can you file a bug report?

But is it really a bug?
Have a look at the attached image.

If I add -Wno-padded, then the warning disappears.

In my opinion, adding -Wno-padded to the default flags would be sufficient.

>
> --
> Sent from cellphone, sorry for the typos
>
>
>
> On March 3, 2016 22:22:26 Andrzej Telszewski <atelszewski at gmail.com> wrote:
>
>> On 03/03/16 21:55, Bubke Marco wrote:
>>> You don't have to silence the warning,  it is a warning not a error. And you can  change that in the settings.
>>>
>>> I think it quite informative that
>>>
>>> bool x, y,  z;
>>> int w;
>>> char c;
>>>
>>> Is not optimal. If you don't like that disable it in the settings.
>>
>> I do think that having this kind of information is useful, but in my
>> opinion -Wno-padded should be default, and turning on the warning should
>> be left to those who need it. I personally added -Wno-padded to the
>> clang model settings.
>>
>> Say you have a struct like that:
>> struct nopad
>> {
>>     bool flag1;
>>     bool flag2;
>> };
>>
>> It is perfectly fine structure and you don't have to pad it, yet you get
>> the warning. I would understand, if the warning told you to re-arrange
>> the members, but it simply warns you about what is the default compiler
>> behavior, that it will add 2 or 6 bytes of padding. This has been the
>> default compiler behavior for ages, so I don't see the point of giving
>> the warning by default;) In addition, the padding depends on the
>> architecture you're compiling for, so you would have to take it into
>> account.
>>
>> I'm not against the warning, I'm just saying it shouldn't be enabled by
>> default.
>>
>> My real structure is like that:
>> typedef struct
>> {
>>     string name;
>>     bool can_span;
>> } info_key_t;
>>
>> There is nothing sensible I can change to make the warning disappear.
>>
>>>
>>> --
>>> Sent from cellphone, sorry for the typos
>>>
>>>
>>> On March 3, 2016 20:44:28 Andrzej Telszewski <atelszewski at gmail.com> wrote:
>>>
>>>> On 03/03/16 20:23, Bubke Marco wrote:
>>>>> Hi,  we will add more options in 4.0 to the code model,  so you can choose different sets.
>>>>>
>>>>> Anyway I find the padding warning quite useful because it shows that your data structures are sub optimal.
>>>>>
>>>>
>>>> Nope, it does not tell you it's suboptimal. It tells you that compiler
>>>> will add the additional padding/alignment bytes.
>>>>
>>>> Having structure with say 3 bool's and nothing more is perfectly fine.
>>>> In such a case, to silence the warning, I would have to add some dummy
>>>> fields, which most of the time is not necessary.
>>>>
>>>>> --
>>>>> Sent from cellphone, sorry for the typos
>>>>>
>>>>>
>>>>>
>>>>> On March 3, 2016 19:30:31 Andrzej Telszewski <atelszewski at gmail.com> wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> Qt Creator: 3.6.0
>>>>>>
>>>>>> Could _-Wno-padded_ flag be added to the Clang Code Model flags?
>>>>>> I don't believe that warning about padding should be the default behavior.
>>>>>>
>>>>>> --
>>>>>> Best regards,
>>>>>> Andrzej Telszewski
>>>>>> _______________________________________________
>>>>>> Qt-creator mailing list
>>>>>> Qt-creator at qt-project.org
>>>>>> http://lists.qt-project.org/mailman/listinfo/qt-creator
>>>>>
>>>>
>>>>
>>>> --
>>>> Best regards,
>>>> Andrzej Telszewski
>>>
>>> --
>>> Sent from cellphone, sorry for the typos
>>> _______________________________________________
>>> Qt-creator mailing list
>>> Qt-creator at qt-project.org
>>> http://lists.qt-project.org/mailman/listinfo/qt-creator
>>>
>>
>>
>> --
>> Pozdrawiam,
>> Best regards,
>> Andrzej Telszewski
> .
>


-- 
Pozdrawiam,
Best regards,
Andrzej Telszewski
-------------- next part --------------
A non-text attachment was scrubbed...
Name: struct_padding.png
Type: image/png
Size: 11196 bytes
Desc: not available
URL: <http://lists.qt-project.org/pipermail/qt-creator/attachments/20160304/45f3d2e6/attachment.png>