Re: [PATCH] libpoke: Make all symbols hidden by default

[Jose E. Marchesi]

Hi Mohammad!

Thank you for this patch!  It certainly feels good to get rid of all
these __attribute__ ((visibility ("hidden"))) :)

> 2020-10-26  Mohammad-Reza Nabipoor  <m.nabipoor@yahoo.com>
>
>       * bootstrap.conf: Add `lib-symbol-visibility` module to `libpoke`.
>       * libpoke/Makefile.am: Add CPP flags to hide symbols by default.
>       * libpoke/libpoke.h: Define `LIBPOKE_API` macro. Mark all public
>       functions with `LIBPOKE_API`.
>       * libpoke/ios.h: Remove `__attribute__ ((visibility ("hidden")))`.
>       * libpoke/pkl-asm.h: Likewise.
>       * libpoke/pkl-ast.h: Likewise.
>       * libpoke/pkl-diag.h: Likewise.
>       * libpoke/pkl-env.h: Likewise.
>       * libpoke/pkl-parser.h: Likewise.
>       * libpoke/pkl-pass.h: Likewise.
>       * libpoke/pkl.h: Likewise.
>       * libpoke/pkl-alloc.h: Likewise.
>       * libpoke/pvm-program.h: Likewise.
>       * libpoke/pvm-val.h: Likewise.
>       * libpoke/pvm.h: Likewise.

The changes above are OK for master.  Feel free to put them in their own
commit and push them.

>       * etc/libpoke-public-functions: New file. Name of all public functions
>       of `libpoke` per line.

Let's talk a bit about the best way to validate the interface, before
committing to maintain something like etc/libpoke-public-functions,

It seems to me that what constituted the API can the reliably be
automatically determined from libpoke.h by looking at the places where
LIBPOKE_API is used.  No need to maintain a separated list by hand.

At some point I imagine we will be using version files anyway, where we
will have to list the exported symbols explicitly anyway.  But I say
let's cross that bridge if/when we reach that river.  We don't need that
extra complexity now that we aren't even released!

Using poke to look in the shared object for the global symbols is of
course much more preferable than using readelf! ;)

> diff --git a/DEV-NEWS b/DEV-NEWS
> index 709ccc0e..ed9c5dfd 100644
> --- a/DEV-NEWS
> +++ b/DEV-NEWS
> @@ -7,3 +7,8 @@ poke.
>    are permitted in any medium without royalty provided the copyright
>    notice and this notice are preserved.
>  
> +2020-10-26
> +     * libpoke: Make all symbols hidden by default.
> +     * etc/libpoke-public-functions: Sorted list of all public functions of
> +     `libpoke`. Update this file if you add/remove an API function (in
> +     `libpoke/libpoke.h` header file).

I would keep the format of DEV-NEWS simpler, something readable at a
glance.

What about:

2020-10-26
. libpoke is now built with all symbols hidden by default.  Public
  symbols in libpoke.h are explicitly marked as such.