RFR: 8152635: Create a UL class to represent a Log + Level combination

[Stefan Karlsson]

Thanks, Bengt.

StefanK

On 2016-04-04 10:49, Bengt Rutisson wrote:
>
> Hi StefanK,
>
> On 2016-04-04 10:39, Stefan Karlsson wrote:
>> Hi all,
>>
>> Here's an updated webrev with fixes for the issues found by Bengt and 
>> Marcus:
>>  http://cr.openjdk.java.net/~stefank/8152635/webrev.02.delta/
>>  http://cr.openjdk.java.net/~stefank/8152635/webrev.02/
>
> Looks good.
>
> Thanks,
> Bengt
>
>>
>> Thanks,
>> StefanK
>>
>> On 2016-03-29 15:46, Stefan Karlsson wrote:
>>> Hi all,
>>>
>>> Please review this patch to introduce a Unified Logging class to 
>>> describe a combination of a tagset and a log level.
>>>
>>> http://cr.openjdk.java.net/~stefank/8152635/webrev.01
>>> https://bugs.openjdk.java.net/browse/JDK-8152635
>>>
>>> The patch is applied on top of the patch in:
>>> http://mail.openjdk.java.net/pipermail/hotspot-dev/2016-March/022302.html 
>>>
>>>
>>> With this class we could write code as:
>>> LogTarget(Debug, gc, heap) log;
>>> if (log.is_enabled()) {
>>>   log.print(...);
>>>   log.print(...);
>>>   ... = log.stream();
>>> }
>>>
>>> instead of the current model:
>>> Log(gc, heap) log;
>>> if (log.is_debug()) {
>>>   log.debug(...)
>>>   log.debug(...)
>>>   ... = log.debug_stream():
>>> }
>>>
>>> The LogTarget class/macro ensures that we only mention the log level 
>>> once, so that we don't accidentally log to the wrong level. The 
>>> previous version forces the coder to repeat 'debug' four times.
>>>
>>> One example where the wrong log level has been used:
>>> https://bugs.openjdk.java.net/browse/JDK-8152962
>>>
>>> I've converted one function in compactibleFreeListSpace.cpp to show 
>>> how to use the new class.
>>>
>>> Test: new internal vm test, jprt
>>>
>>> Thanks,
>>> StefanK
>>
>