RFR: 8370438: Offer link time optimization support on library level [v10]

[Sergey Bylokhov]

On Fri, 7 Nov 2025 15:06:51 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> We currently have support for LTO (link time optimization) for Hotspot/libjvm, that can be enabled as a JVM feature.
>> But for other JDK native libs, we do not have support for this feature.
>> LTO and sometimes lead to faster and also in some cases smaller binaries, so support for this might be interesting also for other libs and not only libjvm.
>
> Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add lto to EXTRA_FLAGS, not to OPT

make/modules/java.desktop/lib/ClientLibraries.gmk line 229:

> 227:       EXCLUDES := $(LIBSPLASHSCREEN_EXCLUDES), \
> 228:       OPTIMIZATION := SIZE, \
> 229:       LINK_TIME_OPTIMIZATION := true, \

You do not need to change it in this patch, it can be done separately per lib.

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PR Review Comment: https://git.openjdk.org/jdk/pull/27976#discussion_r2505913339