From baf2a265c71113a91f6971313ef191be9e77ef6a Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Tue, 7 Jun 2022 11:11:03 -0300 Subject: misc: Optimize internal usage of __libc_single_threaded By adding an internal alias to avoid the GOT indirection. On some architecture, __libc_single_thread may be accessed through copy relocations and thus it requires to update also the copies default copy. This is done by adding a new internal macro, libc_hidden_data_{proto,def}, which has an addition argument that specifies the alias name (instead of default __GI_ one). Checked on x86_64-linux-gnu and i686-linux-gnu. Reviewed-by: Fangrui Song --- nptl/pthread_create.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'nptl') diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c index e7a099acb7..a06d611e32 100644 --- a/nptl/pthread_create.c +++ b/nptl/pthread_create.c @@ -624,9 +624,12 @@ __pthread_create_2_1 (pthread_t *newthread, const pthread_attr_t *attr, /* Avoid a data race in the multi-threaded case, and call the deferred initialization only once. */ - if (__libc_single_threaded) + if (__libc_single_threaded_internal) { late_init (); + __libc_single_threaded_internal = 0; + /* __libc_single_threaded can be accessed through copy relocations, so + it requires to update the external copy. */ __libc_single_threaded = 0; } -- cgit 1.4.1