RFR: 8232084: HotSpot build failed with GCC 9.2.1

[Yasumasa Suenaga]

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?


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
>>>>