Re: [Tarantool-patches] [PATCH 00/43] Unhide symbols

[Cyrill Gorcunov <gorcunov@gmail.com>]

On Mon, Apr 13, 2020 at 04:26:41PM +0200, Vladislav Shpilevoy wrote:
> Another possible improvement I can think of - instead of
> using 'static void *syms[]' everywhere I could make all
> *_export_syms() functions take an argument like
> 
>     void (*export_f)(void **syms)
> 
> And they would pass pointers at their functions there.
> 
> The main file, exports.c, would pass here a function, which
> does nothing. Or does panic(), but we will never call these
> _export_syms() functions actually. Will place it under
> something like 'if (time(NULL) == 0)'.
> 
> That would allow to turn static arrays into normal arrays on
> the stack and make the executable's size a bit smaller.

Vladislav, let me summarize the overall idea and the problem:

1) Currently tarantool *already* uses extra/exports file during
   build procedure, where we keep the list of functions to be
   avaliable via Lua ffi interface to the tarantool users.

   While these functions are NOT part of API people relay on them
   and use actively, right? In other words they are semi-API I wold
   say.

2) Due to our build procedure specifics we link final executable from
   static libraries (or archives) and compiler may think that some of
   the symbols are not even used and trip them off in optimization
   phase.

3) Instead of supporting separate extra/exports file we bind symbols
   to the source files were they are defined.

   Actually I would prefer more explicit way as I shown you in face
   to face talk, but this is definitely not the option for current
   timeline. We can try to implement it later.