[Bug libstdc++/51333] [7/8 Regression] cxxabi.h incompatible with -fkeep-inline-functions at link time

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51333

--- Comment #14 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Author: redi
Date: Mon Sep  2 11:10:00 2019
New Revision: 275309

URL: https://gcc.gnu.org/viewcvs?rev=275309&root=gcc&view=rev
Log:
PR libstdc++/51333 Define recursive_init_error constructor non-inline

The recursive_init_error class is defined in a header, with an inline
constructor, but the definition of the vtable and destructor are not
exported from the shared library. With -fkeep-inline-functions the
constructor gets emitted in user code, and requires the (non-exported)
vtable. This fails to link.

As far as I can tell, the recursive_init_error class definition was
moved into <cxxabi.h> so it could be documented with Doxygen, not for
any technical reason. But now it's there (and documented), somebody
could be relying on it, by catching that type and possibly performing
derived-to-base conversions to the std::exception base class. So the
conservative fix is to leave the class definition in the header but make
the constructor non-inline. This still allows the type to be caught and
still defines its base class.

Backport from mainline
2019-07-29  Jonathan Wakely  <jwakely@redhat.com>

        PR libstdc++/51333
        * libsupc++/cxxabi.h (__gnu_cxx::recursive_init_error): Do not define
        constructor inline.
        * libsupc++/guard_error.cc (__gnu_cxx::recursive_init_error): Define
        constructor.
        * testsuite/18_support/51333.cc: New test.

Added:
    branches/gcc-7-branch/libstdc++-v3/testsuite/18_support/51333.cc
Modified:
    branches/gcc-7-branch/libstdc++-v3/ChangeLog
    branches/gcc-7-branch/libstdc++-v3/libsupc++/cxxabi.h
    branches/gcc-7-branch/libstdc++-v3/libsupc++/guard_error.cc