hurd: Only check for TLS initialization inside rtld or in static builds
commite2756903329365134089d23548e9083d23bc3dd9
authorSergey Bugaev <bugaevc@gmail.com>
Sun, 19 Mar 2023 15:10:07 +0000 (19 18:10 +0300)
committerSamuel Thibault <samuel.thibault@ens-lyon.org>
Fri, 14 Apr 2023 10:31:22 +0000 (14 10:31 +0000)
tree99c465b707b132731dc6b8c29adae59f5d8dd23b
parentba00d787f3469b02032766b074d4df9071fa7e24
hurd: Only check for TLS initialization inside rtld or in static builds

When glibc is built as a shared library, TLS is always initialized by
the call of TLS_INIT_TP () macro made inside the dynamic loader, prior
to running the main program (see dl-call_tls_init_tp.h). We can take
advantage of this: we know for sure that __LIBC_NO_TLS () will evaluate
to 0 in all other cases, so let the compiler know that explicitly too.

Also, only define _hurd_tls_init () and TLS_INIT_TP () under the same
conditions (either !SHARED or inside rtld), to statically assert that
this is the case.

Other than a microoptimization, this also helps with avoiding awkward
sharing of the __libc_tls_initialized variable between ld.so and libc.so
that we would have to do otherwise -- we know for sure that no sharing
is required, simply because __libc_tls_initialized would always be set
to true inside libc.so.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20230319151017.531737-25-bugaevc@gmail.com>
sysdeps/mach/hurd/Makefile
sysdeps/mach/hurd/i386/dl-tls-initialized.c [new file with mode: 0644]
sysdeps/mach/hurd/i386/tls.h
sysdeps/mach/hurd/x86/init-first.c
sysdeps/mach/hurd/x86_64/dl-tls-initialized.c [new file with mode: 0644]
sysdeps/mach/hurd/x86_64/tls.h