RFR: 8291065: Creating a VarHandle for a static field triggers class initialization [v7]

[Chen Liang]

On Sat, 3 Jun 2023 02:25:59 GMT, ExE Boss <duke at openjdk.org> wrote:

>> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove lazy init of MH, for all invocation of the Lazy VH needs this MH
>
> src/java.base/share/classes/java/lang/invoke/LazyInitializingVarHandle.java line 106:
> 
>> 104:         UNSAFE.ensureClassInitialized(refc);
>> 105:         this.initialized = true;
>> 106:     }
> 
> This should probably have a fast‑path when `this.initialized` is `true`, so that it can be better constant folded by the **JIT**:
> Suggestion:
> 
>     private void ensureInitialized() {
>         if (this.initialized) {
>             return;
>         }
>         UNSAFE.ensureClassInitialized(refc);
>         this.initialized = true;
>     }

I think I should probably update the MH lambda form as well, to skip the ensure call entirely if JVM has not constant-fold the inefficient form yet.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13821#discussion_r1215184529