RFR: Here are some Thread cleanup patches

[Peter Levart]

Hi,

As far as I think (but please prove me wrong), Stable class is not 
loaded until someone explicitly asks for it in Java code (referring to 
Stable type in bytecode like with Stable.class literal or parsing 
annotations of a field that contains such annotation triggered by Java 
API for annotations).

The VM code that parses some annotations like @Stable, @CallerSensitive, 
@ForceInline, etc... works by matching the Symbol names of annotation 
classes and doesn't need the to load the annotation class for that. See 
parse_annotations in classFileParser.cpp...

Regards, Peter


On 03/28/18 04:21, David Holmes wrote:
> On 28/03/2018 12:07 PM, Martin Buchholz wrote:
>> java -Xlog:class+init=trace -version |& grep -Ew 
>> 'annotation|lang.Thread|Stable'
>> [0.019s][info][class,init] 10 Initializing 'java/lang/Thread' 
>> (0x00000007c0006400)
>
> Thanks.
>
>> Intuitively, class+init should be a subset of class+load, and the 
>> experiment above supports that.
>
> The initialization order can be quite different to the load order.
>
> David
>
>> On Tue, Mar 27, 2018 at 6:59 PM, David Holmes 
>> <david.holmes at oracle.com <mailto:david.holmes at oracle.com>> wrote:
>>
>>     On 28/03/2018 11:50 AM, Martin Buchholz wrote:
>>
>>
>>
>>         On Tue, Mar 27, 2018 at 6:24 PM, Martin Buchholz
>>         <martinrb at google.com <mailto:martinrb at google.com>
>>         <mailto:martinrb at google.com <mailto:martinrb at google.com>>> 
>> wrote:
>>
>>                At least the VM doesn't have to run any risky java code
>>
>>
>>         ??  Why is Martin so sure ??
>>         Let's check:
>>
>>         java -Xlog:class+load=trace -version |& grep -Ew
>>         'annotation|lang.Thread'
>>         [0.010s][info ][class,load] java.lang.Thread source: 
>> jrt:/java.base
>>         [0.010s][info ][class,load]
>>         java.lang.Thread$UncaughtExceptionHandler source: jrt:/java.base
>>         [0.012s][info ][class,load] java.lang.annotation.Annotation
>>         source: jrt:/java.base
>>
>>         So Stable does __not__ have to be class-loaded when Thread is
>>         class-loaded.
>>
>>
>>     Can you check with class+initialization please.
>>
>>     Thanks,
>>     David
>>
>>