RFR: 8370438: Offer link time optimization support on library level

[Matthias Baesken]

On Fri, 24 Oct 2025 13:58:24 GMT, Julian Waters <jwaters at openjdk.org> wrote:

> It might be better if we offered this as an option to turn off and on through configure (My personal fork of the JDK has something along the lines of --enable-linktime-opt, can't remember the exact name) rather than making some native code have to use LTO. Additionally I also think this is better done similar to how HotSpot does it instead of adding LTO options as an exported Makefile variable and adding a new parameter to SetupNativeCompilation.

The PR gives developers working on some lib , where LTO looks promising, the ability to test the feature on the specific lib.
Enabling it for ALL jdk libs is of course possible too (I did this for experiments locally as well);  the lib idea was discussed here
https://github.com/openjdk/jdk/pull/22464#issuecomment-3423727477

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PR Comment: https://git.openjdk.org/jdk/pull/27976#issuecomment-3455420884