bug#44238: 28.0.50; [feature/native-comp] Build trampolines for FULL_AOT builds

[Andrew Whatson <whatson@gmail.com>]

On Sat, 28 Aug 2021 at 03:24, Lars Ingebrigtsen <larsi@gnus.org> wrote:
>
> > Sorry for the delay, I have been (slowly) working on a patch to build
> > the trampolines as part of a NATIVE_FULL_AOT build.  Adding a step to
> > the Makefile was easy, but all the trampolines end up in
> > ~/.emacs.d/eln-cache instead of the build directory.  I'll invest some
> > more time over the weekend to get this working.
> >
> > I understand that these are relatively cheap to build, but my
> > motivation is that when building binary packages for wider
> > distribution, any work ahead-of-time will pay off many times over.
> > I'd at least like to gather some data on the impact to build times and
> > package size from pre-building the trampolines before closing this
> > issue, if you don't strongly disagree.
>
> This was half a year ago -- did you make any progress in this area?

After playing with it some more, I have to agree with Andrea that
pre-compiling trampolines seems not really worth it.  My reasonably
heavy emacs config needs only 37 trampolines, which take up 400K on
disk.  It's difficult to justify building ~1500 trampolines to ship
~15M of binaries which would never be used.

I also didn't come up with a satisfactory Makefile patch, so at this
point probably best to close the ticket.

Cheers,
Andrew