RFR: 8338768: Introduce runtime lookup to check for static builds [v2]

[Julian Waters]

On Wed, 21 Aug 2024 22:14:40 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> As a preparation for Hermetic Java, we need to have a way to look up during runtime if we are using a statically linked library or not.
>> 
>> This change will be the first step needed towards compiling the object files only once, and then link them into either dynamic or static libraries. (The only exception will be the linktype.c[pp] files, which needs to be compiled twice, once for the dynamic libraries and once for the static libraries.) Getting there will require further work though. 
>> 
>> This is part of the changes that make up the draft PR https://github.com/openjdk/jdk/pull/19478, which I have broken out.
>
> Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Also update build to link properly

This does make me wonder: What if the new method for checking if the VM was statically linked was inlined? Then the problem comes back yet again as the object files need to be recompiled once more. This is possible if Link Time Optimization is switched on, and I don't like the implication that LTO might be removed as a result just to make this work

-------------

PR Comment: https://git.openjdk.org/jdk/pull/20666#issuecomment-2323416932