RFR: 8232084: HotSpot build failed with GCC 9.2.1

[Yasumasa Suenaga]

On 2019/10/17 13:21, David Holmes wrote:
> On 17/10/2019 2:20 pm, Yasumasa Suenaga wrote:
>> On 2019/10/17 12:49, David Holmes wrote:
>>> On 17/10/2019 12:45 pm, Yasumasa Suenaga wrote:
>>>> On 2019/10/17 11:39, David Holmes wrote:
>>>>> On 17/10/2019 12:19 pm, Yasumasa Suenaga wrote:
>>>>>> On 2019/10/17 9:34, David Holmes wrote:
>>>>>>> On 17/10/2019 10:07 am, serguei.spitsyn at oracle.com wrote:
>>>>>>>> Hi Yasumasa,
>>>>>>>>
>>>>>>>> It looks good.
>>>>>>>> One tip:
>>>>>>>>
>>>>>>>> + // This code would be warned as "stringop-truncation" by GCC 8 or later.
>>>>>>>> +PRAGMA_DIAG_PUSH
>>>>>>>> +PRAGMA_STRINGOP_TRUNCATION_IGNORED
>>>>>>>>         strncpy(buf, str, len);
>>>>>>>> +PRAGMA_DIAG_POP
>>>>>>>>
>>>>>>>>
>>>>>>>> I'd suggest to place the comment before the line with strncopy().
>>>>>>>
>>>>>>> I'd suggest just dropping the comment as it adds nothing, further gcc 8 is not flagging this use of strncpy.
>>>>>>
>>>>>> The comment is suggested in [1].
>>>>>> Indeed stringop-truncation warning was not reported by GCC 8, but this option introduced in it,
>>>>>> and I agree with Ioi to add the comment for other developers why this #pragma is needed.
>>>>>
>>>>> PRAGMA_STRINGOP_TRUNCATION_IGNORED
>>>>>
>>>>> seems to pretty clearly state what the issue is to me. But if you want to add a comment to make that more clear fine. But don't mention gcc 8 as it is not relevant to the need for the pragma now.
>>>>
>>>> I'd like to change the comment as below:
>>>>
>>>>      This code would be warned as "stringop-truncation" by modern GCC
>>>>
>>>> Is it ok?
>>>
>>> Grammatically it needs work. I propose
>>>
>>> // This code can cause a "stringop-truncation" warning with gcc
>>>
>>> "modern" will become inaccurate as time goes by.
>>
>> Thanks!
>> To be clear that our code is correct, I will change the comment as below:
>>
>>    // This code can cause a "stringop-truncation" warning with gcc incorrectly
> 
> // This code can incorrectly cause a "stringop-truncation" warning with gcc
> 
> Assuming Ioi feels that is sufficient.

Thanks! and sorry for my English...

Yasumasa


> Thanks,
> David
> 
>>
>> Yasumasa
>>
>>
>>> Thanks,
>>> David
>>>
>>>>
>>>> Yasumasa
>>>>
>>>>
>>>>> Thanks,
>>>>> David
>>>>>
>>>>>>
>>>>>> Yasumasa
>>>>>>
>>>>>>
>>>>>> [1] https://mail.openjdk.java.net/pipermail/serviceability-dev/2019-October/029578.html
>>>>>>
>>>>>>> Otherwise okay.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> David
>>>>>>>
>>>>>>>> Not  subject for re-review.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Serguei
>>>>>>>>
>>>>>>>>
>>>>>>>> On 10/16/19 16:25, Yasumasa Suenaga wrote:
>>>>>>>>> (Re-send email because I could not send original email to serviceability-dev and hotspot-compiler-dev)
>>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> We discussed the fix for JDK-8232084 in [1], and I think we should fix it with #pragma.
>>>>>>>>> I uploaded new webrev. Could you review it?
>>>>>>>>>
>>>>>>>>>   JBS: https://bugs.openjdk.java.net/browse/JDK-8232084
>>>>>>>>>   webrev: http://cr.openjdk.java.net/~ysuenaga/JDK-8232084/webrev.03/
>>>>>>>>>
>>>>>>>>> This change has passed the tests on submit repo (mach5-one-ysuenaga-JDK-8232084-1-20191016-1534-5969882).
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>>
>>>>>>>>> Yasumasa
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> [1] https://mail.openjdk.java.net/pipermail/serviceability-dev/2019-October/029547.html
>>>>>>>>