RFR: 8365238: 'jfr' feature requires 'services' with 'custom' build variant

[Aleksey Shipilev]

On Mon, 11 Aug 2025 10:55:44 GMT, Francesco Andreuzzi <duke at openjdk.org> wrote:

> In this PR I add an `autoconfigure` check to make sure that `jfr` is not built without the feature `services`, which would lead to the following error:
> 
> /jdk/src/hotspot/share/jfr/periodic/jfrPeriodic.cpp: In member function ‘virtual void VM_GC_SendObjectCountEvent::doit()’:
> /jdk/src/hotspot/share/jfr/periodic/jfrPeriodic.cpp:402:5: error: ‘ObjectCountEventSender’ has not been declared
>   402 |     ObjectCountEventSender::enable_requestable_event();
>       |     ^~~~~~~~~~~~~~~~~~~~~~
> /jdk/src/hotspot/share/jfr/periodic/jfrPeriodic.cpp:404:5: error: ‘ObjectCountEventSender’ has not been declared
>   404 |     ObjectCountEventSender::disable_requestable_event();
>       |     ^~~~~~~~~~~~~~~~~~~~~~
> 
> 
> To reproduce:
> 
> sh configure --with-jvm-variants=custom --with-conf-name=cstm --enable-jvm-feature-jfr --enable-jvm-feature-serialgc
> make -j hotspot CONF_NAME=cstm

Looks like `ObjectCountEventSender` is JFR-specific, and `#if INCLUDE_SERVICES` in `objectCounterEventSender.cpp` is incorrect. If this is the only dependency between `jfr` and `services`, we should just fix `ObjectCountEventSender`.

Agree, @egahlin?

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PR Comment: https://git.openjdk.org/jdk/pull/26723#issuecomment-3174898061