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From: "joseph at codesourcery dot com" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug build/26260] undefined reference to `_Unwind_Resume'
Date: Fri, 17 Jul 2020 20:48:35 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D26260

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery =
dot com> ---
Linking libc with libgcc_eh is not correct.  See the four-paragraph=20
comment on the definitions of libunwind, gnulib and related variables for=20
an explanation.  There are various requirements on libgcc and the GCC=20
build process to avoid such circular dependencies and to ensure that a=20
stripped glibc binary built with an inhibit_libc GCC is identical to one=20
built following a longer sequence of alternating GCC and glibc builds.=20=20
It seems you've found another such requirement: libgcc must not be built=20
in a way that introduces references to EH symbols in the code statically=20
linked into shared libc.

glibc does not itself support being built with -O0 either.  It would be=20
desirable to do so, but there might still be requirements in that case for=
=20
some individual files or functions to be compiled with optimization.=20=20
Likewise, even if a libgcc mostly built with -O0 works for building glibc,=
=20
it seems optimization might be required for building some files therein.

--=20
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