RFR: 8369305: Adjust usage of CDS in the boot JDK

[Erik Joelsson]

On Fri, 10 Oct 2025 11:40:45 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

> Currently we dump an archive in the configure process, this might not be needed/beneficial any more.
> 
> Building with and without the change on Linux x86_64 (product)  shows similar build times.

make/autoconf/boot-jdk.m4 line 431:

> 429: 
> 430:   # Otherwise optimistically use the system-wide one, if one is present
> 431:   UTIL_ADD_JVM_ARG_IF_OK([-Xshare:auto],boot_jdk_jvmargs,[$JAVA])

I don't think this is needed. The default archive should be picked up automatically without an option needed. I also tried a build with and without your patch, as well as without this line, and they were all similar enough. Also, there is an extra newline above this block.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27741#discussion_r2420417152