RFR: 8354954: Typed static memory for late initialization of static class members in Hotspot [v11]

[Quan Anh Mai]

On Thu, 19 Jun 2025 07:57:46 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

>> FWIW, the current implementation doesn't allow me to do:
>> 
>> struct Thing {
>>   Thing(int value) {}
>> };
>> ...
>> Defered<Thing> _deferred;
>> ...
>> _deferred.initialize(1);
>> 
>> I have to write last piece as:
>> 
>> int temp = 1;
>> _deferred.initialize(temp);
>
> Yeah,
> 
> and the current implementation will copy-construct its argumens as far as I understand. So, we gain nothing. I'd really like to see us getting in move semantics so that we can have
>  
> ```c++
> template<typename... As>
> void init(As&&... args) {
>     assert(is_death_pattern(), "StaticArea already initialized");
>     new (as()) T(args...);
> }
> 
> 
> et voilà, it'll work as we want it to.

This seems like something we overlooked, should this be:

    template<typename... Ts>
    void initialize(const Ts&... args);

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PR Review Comment: https://git.openjdk.org/jdk/pull/24689#discussion_r2156433500