RFR: 8232084: HotSpot build failed with GCC 9.2.1

[Ioi Lam]

On 10/16/19 9:25 PM, Yasumasa Suenaga wrote:
> 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
>

I am happy with David's version. Let's get this over with :-)

Thanks to everyone, especially to Yasumasa's patience with this. 
お疲れ様です！

- Ioi
>
>> 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
>>>>>>>>>