commit 55460da26c2756ec057c03c7d8641eda861bfcd2
author Christian Brabandt <cb@256bit.org> Tue Aug 29 21:31:28 2023 +0200
committer Christian Brabandt <cb@256bit.org> Tue Aug 29 21:31:28 2023 +0200
tree 1cd5571d754155ed894666f7f27ef421ba6f8df9
parent 0e82b59df3fc12dc006e45e17222bcbb0462903f

patch 9.0.1818: dynamically linking perl is broken

Problem:  dynamically linking perl is broken
Solution: Fix all issues

This is a combination of several commits:

1) Fix if_perl.xs not being able to build on all versions of Perl (5.30)

This fixes the dynamic builds of Perl interface. The Perl interface file
previously had to manually copy and paste misc inline functions verbatim
from the Perl headers, because we defined `PERL_NO_INLINE_FUNCTIONS`
which prevents us form getting some function definitions. The original
reason we defined it was because those inline functions would reference
Perl functions that would cause linkage errors.

This is a little fragile as every time a new version of Perl comes out,
we inevitably have to copy over new versions of inline functions to our
file, and it's also easy to miss updates to existing functions.

Instead, remove the `PERL_NO_INLINE_FUNCTIONS` define, remove the manual
copy-pasted inline functions. Simply add stub implementations of the
missing linked functions like `Perl_sv_free2` and forward them to the
DLL version of the function at runtime. There are only a few functions
that need this treatment, and it's a simple stub so there is very low
upkeep compared to copying whole implementations to the file.

Also, fix the configure script so that if we are using dynamic linkage,
we don't pass `-lperl` to the build flags, to avoid accidental external
linkage while using dynamic builds. This is similar to how Python
integration works.

2) Fix GIMME_V deprecation warnings in Perl 5.38

Just use GIMME_V, and only use GIMME when using 5.30 to avoid needing to
link Perl_block_gimme. We could provide a stub like the other linked
functions like Perl_sv_free2, but simply using GIMME is the simplest and
it has always worked before.

3) Fix Perl 5.38 issues

Fix two issues:

3.1. Perl 5.38 links against more functions in their inline headers, so we
   need to stub them too.

3.2. Perl 5.38 made Perl_get_context an inline function, but *only* for
   non-Windows build. Fix that. Note that this was happening in Vim
   currently, as it would build, but fail to run Perl code at runtime.

4) Fix Perl 5.36/5.38 when thread local is used

Perl 5.36 introduced using `_Thread_local` for the current context,
which causes inline functions to fail. Create a stub
`PL_current_context` thread local variable to satisfy the linker for
inlined functions. Note that this is going to result in a different
`PL_current_context` being used than the one used in the library, but so
far from testing it seems to work.

5) Add docs for how to build Perl for dynamic linking to work

closes: #12827
closes: #12914

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>