RFR: 8351322: Parameterize link option for pthreads [v2]

[snake66]

On Mon, 17 Mar 2025 06:41:31 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> @magicus why can't we just use `-pthread` everywhere? My recollection is that `-pthread` both sets compiler directives needed for pthread programming and links to libpthread, so it seems to be what we should be using. ??
>
>> Another follow-up is if it would hurt to include $LIBPTHREAD for _all_ Hotspot tests, to avoid the huge list. @dholmes-ora Do you have anything coming to mind directly that would make that infeasible, or is it just a matter of testing to add it and see if any tests fail?
> 
> Sorry I was out of contact for a while. I can't imagine why any test would fail if linked with libpthread, given the VM is linking to it anyway.
> 
>> We can then check if we can turn -lpthread into -pthread on Linux as a follow up.
> 
> I have a vague recollection that at one time `-pthread` set some _POSIX_SOURCE define (or something like that) which conflicted with our use of some gcc specific things. But that was long ago so I would try it and see. Of couise it then becomes hard to classify what kind of flag this is because it isn't strictly a library flag.

> > Another follow-up is if it would hurt to include $LIBPTHREAD for _all_ Hotspot tests, to avoid the huge list. @dholmes-ora Do you have anything coming to mind directly that would make that infeasible, or is it just a matter of testing to add it and see if any tests fail?
> 
> (...) I can't imagine why any test would fail if linked with libpthread, given the VM is linking to it anyway.

I'm happy to test this, if you want. Won't have time this week, though.

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

PR Comment: https://git.openjdk.org/jdk/pull/23930#issuecomment-2729033496