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>