Horton

Re: Use -fvisibility=hidden for shared libraries

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>, pgsql-hackers@postgresql.org
Date: 2022-01-11T00:01:36Z
Lists: pgsql-hackers

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Andres Freund <andres@anarazel.de> writes:
> [ v2-0001-Use-hidden-visibility-for-shared-libraries-where-.patch ]

This seems like a good idea, but it's failing to apply right now,
mainly because of some cleanup I did in e04a8059a.  As far as I can
tell given the now-clarified meanings of PGDLLIMPORT/PGDLLEXPORT,
this patch shouldn't be touching PGDLLIMPORT.  The attached revision
works for me under gcc 8.5 and clang 13.

Also, it seemed like you'd maybe been more enthusiastic than necessary
about plastering PGDLLEXPORT on things.  I got through check-world
cleanly without the diffs in either ltree.h or worker_spi.c (although
I confess being confused why I didn't need the latter).  I didn't try
individually removing other diffs.  Those diffs are still in v3 below,
but we should clarify exactly which functions need marking.

			regards, tom lane

Commits

  1. Mark all symbols exported from extension libraries PGDLLEXPORT.

  2. Default to hidden visibility for extension libraries where possible

  3. Remove now superfluous declarations of dlsym()ed symbols.

  4. Add central declarations for dlsym()ed symbols