RFR: 8333658: NMT: Use an allocator with 4-byte pointers to save memory in NativeCallStackStorage [v34]

[Thomas Stüfe]

Johan, I would just remove the noncopyable. Its questionable anyway, there
is no reason one shouldnt be able to copy the AWFL, in particular because
client code just uses indices, not pointers.

On Tue 25. Jun 2024 at 21:01, Sonia Zaldana Calles <szaldana at openjdk.org>
wrote:

> On Tue, 25 Jun 2024 17:57:36 GMT, Johan Sjölen <jsjolen at openjdk.org>
> wrote:
>
> >> Thank you for the in-depth reviewing of this change.
> >
> >> Hi @jdksjolen, I'm seeing some build failures after this PR got
> integrated. I filed [JDK-8335108](
> https://bugs.openjdk.org/browse/JDK-8335108) for reference.
> >
> > Hi Sonia, thanks for contacting me. It seems like this is a C++20 issue,
> but Hotspot only supports up to C++14. Here's a Godbolt for reproducing the
> issue, change the `-std=c++14` to `-std=c++20` to see the issue:
> https://godbolt.org/z/eK5GaTceY
> >
> > That ought to mean that I don't have to back out this PR and
> re-introduce it with the bug fixed, but I still think that we should fix
> the bug because we do want to get to C++20 some day :-).
> >
> > There's something weird with the fact that you get builds with C++20
> support enabled, not sure what your configure options are.
>
> Hi @jdksjolen, thanks for looking into it!
>
> > Hi Sonia, thanks for contacting me. It seems like this is a C++20 issue,
> but Hotspot only supports up to C++14. Here's a Godbolt for reproducing the
> issue, change the `-std=c++14` to `-std=c++20` to see the issue:
> https://godbolt.org/z/eK5GaTceY
> >
> > That ought to mean that I don't have to back out this PR and
> re-introduce it with the bug fixed, but I still think that we should fix
> the bug because we do want to get to C++20 some day :-).
>
> Makes sense. I'll submit a follow-up PR to fix this.
>
> > There's something weird with the fact that you get builds with C++20
> support enabled, not sure what your configure options are.
>
> I'm not sure. I don't have any special configure options. I came across
> this error after a plain ```bash configure``` but I guess my installed g++
> version is 14.1.1.
>
> -------------
>
> PR Comment: https://git.openjdk.org/jdk/pull/18979#issuecomment-2189747196
>
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