bug#43725: 28.0.50; Include feature/native-comp into master

[Andrea Corallo]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Andrea Corallo <akrl@sdf.org>
>> Cc: larsi@gnus.org, monnier@iro.umontreal.ca, 43725@debbugs.gnu.org
>> Date: Tue, 09 Mar 2021 20:09:03 +0000
>> 
>> >> > Looking at a running Emacs, I see that it loads the *.eln files that
>> >> > are preloaded.  I would expect those to be dumped into the emacs.pdmp
>> >> > file, as it happens with *.elc files.  If all the stuff is dumped into
>> >> > emacs.pdmp and loaded from there, why does Emacs still need to load
>> >> > those *.eln files as shared libraries?
>> >> 
>> >> For loaded you mean entering in 'load_comp_unit'?
>> >
>> > I looked at the shared libraries loaded by the program as shown by the
>> > GDB "info sharedlibrary" command.
>> 
>> Okay, that's normal.  The pdumper is dumping only the pseudovector
>> representing the CU.  When the image is loaded pdumper calls
>> 'load_comp_unit' to have the dynamic linker map again the .eln into
>> memory.
>
> This means that, unlike with preloaded *.elc files, one cannot delete
> the preloaded *.eln files once the pdumper file is created, because
> the *.eln files are still needed each time Emacs starts.

Precisely.

  Andrea