Review Request: JDK-8219774: Reexamine the initialization of LangReflectAccess shared secret at AccessibleObject::<clinit>

[Mandy Chung]

Hi David,

Thanks for the review.   I missed to include you in the reviewer list.  
Sorry about that.

Mandy

On 7/21/19 11:19 PM, David Holmes wrote:
> Hi Mandy,
>
> This approach looks much cleaner and safer to me, and the slight 
> shuffling in the init order should not cause any startup issues.
>
> Thanks,
> David
> -----
>
> On 20/07/2019 2:20 am, Mandy Chung wrote:
>> This was a follow up to the observation during the code review
>> of JDK-82193798.
>>
>> Webrev:
>>     http://cr.openjdk.java.net/~mchung/jdk14/8219774/webrev.01/
>>
>> In the current implementation, Modifier::<clinit> provides a hook
>> to initialize the static ReflectionFactory::langReflectAccess field
>> lazily. This was introduced prior to the common shared secrets
>> mechanism.
>>
>> Another observation is that when ReflectionFactory methods are called,
>> there is a Method, Field or Constructor object in hand. In addition,
>> Method class is initialized very early during startup by the VM and
>> so does AccessibleObject class. The ReflectionFactory::newField and
>> newMethod taking the Field/Method parameter are used but not the
>> one without (dead code).
>>
>> This patch cleans up the initialization of LangReflectAccess to
>> AccessibleObject::<clinit> during early startup initPhase1.
>> I also move LangReflectAccess to jdk.internal.access to be consistent
>> with other *Access classes (LangReflectAccess was added before the 
>> common
>> SharedSecrets class was introduced).
>>
>> This also addresses JDK-8227831 the overhead of langReflectAcces being
>> a volatile field on the platform with weak memory model (Thanks to
>> Ogata confirming that this patch is 4% better than the proposed patch
>> for JDK-8227831 [1]).
>>
>> The impact to the class initialization order is minimal. 
>> JavaLangReflectAccess
>> is initialized during initPhase1 (which has been initialized during 
>> initPhase2).
>> SharedSecrets is initialized in initPhase2 and this patch moves it to be
>> initialized followed AccessibleObject.
>>
>> Mandy
>> [1] 
>> https://mail.openjdk.java.net/pipermail/core-libs-dev/2019-July/061352.html