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

[Bubke Marco]

I have similar structures and have never seen the warning for that cases.  Which clang version do you use? 

--
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
>> _______________________________________________
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>> Qt-creator at qt-project.org
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>>
>
>
> -- 
> Pozdrawiam,
> Best regards,
> Andrzej Telszewski