[jdk11u-dev] RFR: 8342629: [11u] Properly message out that shenandoah is disabled [v2]

[Andrew John Hughes]

On Fri, 18 Oct 2024 17:16:46 GMT, Jiří Vaněk <jvanek at openjdk.org> wrote:

>> Unluckily, ShenandoahGC in jdk11 i still disabled by default. In addition, its output is broken:
>> 
>> 
>> checking for dlopen in -ldl... yes
>> checking if shenandoah can be built... checking if zgc can be built... no, platform not supported
>> checking if jvmci module jdk.internal.vm.ci should be built... yes
>> 
>> 
>> In all other JDKs it is enabled by default, and prints correctly yes/no:
>> 
>> checking for dlopen in -ldl... yes
>> checking if shenandoah can be built... yes
>> checking if zgc can be built... yes
>> checking if jvmci module jdk.internal.vm.ci should be built... yes
>> 
>> 
>> 
>> This PR is fixing this. In jdk17 and up , when manually disabled, the "no" is printed.
>
> Jiří Vaněk has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:
> 
>   8342629: [11u] Properly message out that shenandoah is disabled

This looks good to me.

It looks like the bug goes back to the initial introduction of Shenandoah to 11u ([JDK-8250784](https://bugs.openjdk.org/browse/JDK-8250784)) which created this double if-block.

The trunk version in this form would always enable Shenandoah if supported on that platform, up to [the check being moved to `jvm-features.m4`](https://github.com/openjdk/jdk/commit/c1f4ea5d68ce94a628fc68f0ca0b07b842ef2c54#diff-a09b08bcd422d0a8fb32a95ccf85051ac1e69bef2bd420d579f74d8efa286d2f)

Please use `/approval request <reason>` to apply for maintainer approval to get this into 11u. Thanks.

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Marked as reviewed by andrew (Reviewer).

PR Review: https://git.openjdk.org/jdk11u-dev/pull/2946#pullrequestreview-2400014617