[lworld] RFR: 8327636: [lworld] Make primitive wrappers be value class if preview feature is enabled [v2]

[Chen Liang]

On Fri, 8 Mar 2024 03:22:12 GMT, Mandy Chung <mchung at openjdk.org> wrote:

>> As specified in JEP 401, when preview features are enabled, the following standard library classes are considered to be value classes:
>> 
>>     java.lang.Byte
>>     java.lang.Short
>>     java.lang.Integer
>>     java.lang.Long
>>     java.lang.Float
>>     java.lang.Double
>>     java.lang.Boolean
>>     java.lang.Character
>>     java.util.Optional
>>     java.lang.Number
>>     java.lang.Record
>> 
>> 
>> These value classes are loaded only if --enable-preview is set.    All valhalla tests should have preview enabled to ensure testing with the proper set of library classes.
>> 
>> Testing: Run `jdk_valhalla` and `hotspot_valhalla_runtime` with  `-Xint` with and without `--enable-preview`.  The result is pretty good.  [JDK-8327637](https://bugs.openjdk.org/browse/JDK-8327637) and [JDK-8327639](https://bugs.openjdk.org/browse/JDK-8327639) need further investigation.
>
> Mandy Chung has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Removed duplicated Record

src/java.base/share/classes/sun/invoke/util/VerifyAccess.java line 212:

> 210: 
> 211:             // exports are not setup during early VM initialization
> 212:             if (!jdk.internal.misc.VM.isModuleSystemInited()) {

Should we merge this and the `lookupModule == null` early startup cases, and `assert lookupModule == refModule && refModule == Object.class.getModule()` can become `assert lookupModule == refModule && (refModule == null || refModule == Object.class.getModule())`?

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1040#discussion_r1517152683