[Bug jit/64721] SIBABRT becomes a SIGSEGV in jit testsuite

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64721

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|SIBAGRT turns into SIGSEGV  |SIBABRT becomes a SIGSEGV
                   |in jit testsuite            |in jit testsuite

--- Comment #1 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Currently we unconditionally install crash_handler as a signal_handler, and
this itself (ironically) will crash if called after toplev::main cleans up the
global_diagnostic_context.

Three options:

  (A) We could unregister the signal handlers in toplev::finalize immediately
      before global_diagnostic_context has diagnostic_finish called on it,
      potentially restoring whatever signal handlers were there before.

  (B) Don't register signal-handlers at all when run from inside libgccjit.

  (C) Make creation of global_diagnostic_context be idempotent, and don't
      clean it up.

(B) seems best from the POV of a library that aims to be thread-safe: don't
touch signal-handlers when inside libgccjit.  I have a patch for this.