RFR(XS): 8215009: GCC 8 compilation eror in libjli

[David Holmes]

On 22/02/2019 4:55 am, Mikael Vidstedt wrote:
> 
> The wrapper based solution looks much cleaner to me as well. webrev.01 looks good.

Sorry I really don't like it. The wrappers obfuscate and make 
complicated something that is not at all complicated. I have to re-read 
the new code 3 times to figure out what it is even doing!

All that complexity to handle the fact one platform wants to return int 
instead of void* ??

David
-----

> (not a Reviewer)
> 
> Cheers,
> Mikael
> 
>> On Feb 21, 2019, at 9:55 AM, Dmitry Chuyko <dmitry.chuyko at bell-sw.com> wrote:
>>
>> To me thread function wrappers look preferable to platform specific JavaMain signature. Consider this webrev with wrappers:
>>
>> http://cr.openjdk.java.net/~dchuyko/8215009/webrev.01/
>>
>> In some cases JavaMain is called in the same thread and its result is returned from JLI_Launch. ContinueInNewThread is in shared code. And JavaMain uses macro controlled returns.
>> So when JavaMain returns THREAD_FUNC_RETURN changes may contain some quite artificial macro parts in java.c:
>>
>> http://cr.openjdk.java.net/~dchuyko/8215009/webrev.02/
>>
>> -Dmitry
>>
>> On 12/19/18 9:27 AM, David Holmes wrote:
>>> On 19/12/2018 1:56 am, Dmitry Chuyko wrote:
>>>> On 12/18/18 3:39 AM, David Holmes wrote:
>>>>> On 11/12/2018 9:30 pm, Dmitry Chuyko wrote:
>>>>>> On 12/11/18 4:03 AM, David Holmes wrote:
>>>>>>> Hi Dmitry,
>>>>>>>
>>>>>>> On 11/12/2018 12:16 am, Dmitry Chuyko wrote:
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> Please review a small fix in java_md_solinux.c: continuation is not truly compatible with pthread_create start_routine's signature but we control what actually happens. So it makes sense to add intermediate void* cast to silence the error.
>>>>>>>
>>>>>>> I'd be tempted to fix the signature and get rid of all the casts.
>>>>>>
>>>>>> David, the signature is a signature of
>>>>>>
>>>>>> int JNICALL JavaMain(void * _args)
>>>>>>
>>>>>> It would be fun to change it. But still on Windows it is correctly passed to _beginthreadex() and then return code is extracted with GetExitCodeThread(). In case we want it to return void* the cast will move there.
>>>>>
>>>>> I think the current double cast is truly ugly and an ifdef for windows, or a cast for Windows only would be an improvement.
>>>>
>>>> I agree. Maybe making a wrapper function is not so ugly. If there are no objections to changing beginning of the call stack it is quite easy to implement. For consistency it may be done for all 3 points (posix unix, posix mac, windows) or just for posix ones.
>>>>
>>>> It looks like ifdef should be better as long as there are already OS-specific parts in libjli. Again, if there are no objections to have different JavaMain signatures on different platforms. In this case there won't be a signature cast for Windows.
>>>
>>> How about setting
>>>
>>> #define THREAD_FUNC_RETURN int
>>>
>>> in windows/java_md.h.
>>>
>>> Then:
>>>
>>> #ifndef THREAD_FUNC_RETURN
>>>    #define THREAD_FUNC_RETURN void*
>>> #endif
>>>
>>> in java.h (after the other includes).
>>>
>>> Then:
>>>
>>> THREAD_FUNC_RETURN JNICALL
>>> JavaMain(void * _args)
>>>
>>> in java.c.
>>>
>>> ?
>>>
>>> Cheers,
>>> David
>>>
>>>
>>>>
>>>> -Dmitry
>>>>
>>>>>
>>>>> But I won't impose that on you just to silence gcc 8.
>>>>>
>>>>> Cheers,
>>>>> David
>>>>>
>>>>>> -Dmitry
>>>>>>
>>>>>>>
>>>>>>> Cheers,
>>>>>>> David
>>>>>>>
>>>>>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8215009
>>>>>>>> webrev: http://cr.openjdk.java.net/~dchuyko/8215009/webrev.00/
>>>>>>>> testing: submit repo (mach5-one-dchuyko-JDK-8215009-20181207-1625-13615: PASSED)
>>>>>>>>
>>>>>>>> -Dmitry
>>>>>>>>
>