RFR: 8347755: Support static library in jmod [v6]

[Jiangli Zhou]

On Fri, 14 Mar 2025 04:42:49 GMT, Henry Jen <henryjen at openjdk.org> wrote:

>> This PR add --static-libs option to the jmod tool, it's basically mirroring --libs option to support adding a new section of static archive into the jmod file under the new section `static-lib`.
>> 
>> The JMOD magic header contains a MAJOR and MINOR version, we bump up the MINOR version if the --static-libs option is specified; otherwise, keep the MINOR version as 1. This allow created JMOD file without the newly supported static-lib section to continue be consumed by earlier version of jmod tool.
>> 
>> Also fix the formatting for _hermetic_jdk_jimage_offset, which is a julong(uint64_t) as unsigned long long on MacOS, thus need to use %llu.
>
> Henry Jen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Add hotspot static libs to java.base-static-jmod

make/CreateJmods.gmk line 104:

> 102:   endif
> 103: 
> 104:   # Copy hotspot libs, currently only libjvm.a

I just realized that we also need the launcher's `main.o` in the static `java.base.jmod`. Creating a `liblauncher.a` with the `main.o` and including the `liblauncher.a` in `java.base.jmod` seems to be cleaner than including `main.o` directly in the jmod.

When jlinking the final image for the application, if user doesn't provide customized launcher, `liblauncher.a` is used with other needed JDK/VM static libraries for linking the executable using the native linker (e.g. `ld`). If customized launcher is used, the object file(s) or the static library for the customized launcher is then used when linking the executable. `liblauncher.a` is not used in that case.

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PR Review Comment: https://git.openjdk.org/leyden/pull/46#discussion_r1996018727