[RFR] [8u-JFR] 8238076: Fix OpenJDK 7 Bootstrap Broken by JFR Backport

[Andrey Petushkov]

Hi!

Thank you! The patch is Ok with me (I'm not a reviewer though)

Regards,
Andrey

On Wed, Jan 29, 2020 at 6:46 AM Andrew John Hughes
<gnu.andrew at redhat.com> wrote:
>
> Webrev: https://cr.openjdk.java.net/~andrew/openjdk8/8238076/webrev.01/
> Bug: https://bugs.openjdk.java.net/browse/JDK-8238076
>
> The initial backport of JFR in JDK-8223147 introduced a new bootstrap
> tool, src/share/vm/jfr/GenerateJfrFiles.java, within the HotSpot tree.
> Rather than adapting the tool to work with the existing source & target
> options used for bootstrap tools, JDK-8223147 bumped them to 8. In doing
> so, it broke the ability to build the JDK with the previous version (7).
>
> The lambda constructs & use of StringJoiner in GenerateJfrFiles.java can
> be easily replaced with Java 7 compatible usage, thus retaining the
> ability to bootstrap the JDK. The BOOT_SOURCE_LANGUAGE_VERSION and
> BOOT_TARGET_CLASS_VERSION are moved back down to 7 on *BSD, Linux,
> Solaris & Windows.
>
> It seems the values were still at 6 on AIX, so I can only presume the
> build hasn't been tested there. I raised those up to 7 for consistency.
> I guess we could have gone back to 6, but there is no intention to
> support building with OpenJDK 6 anyway.
>
> Ok for JFR tree?
>
> Thanks,
> --
> Andrew :)
>
> Senior Free Java Software Engineer
> Red Hat, Inc. (http://www.redhat.com)
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