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ensure that thread dtv pointer is never null to optimize __tls_get_addr

This commit is contained in:
Rich Felker 2013-06-03 16:35:59 -04:00
parent d926565355
commit 44b4d09fc0
2 changed files with 6 additions and 4 deletions
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8
src/ldso/dynlink.c
View File

@ -740,13 +740,13 @@ void *__copy_tls(unsigned char *mem)
void *__tls_get_addr(size_t *v) void *__tls_get_addr(size_t *v)
{ {
pthread_t self = __pthread_self(); pthread_t self = __pthread_self();
if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]])
return (char *)self->dtv[v[0]]+v[1]; return (char *)self->dtv[v[0]]+v[1];
/* Block signals to make accessing new TLS async-signal-safe */ /* Block signals to make accessing new TLS async-signal-safe */
sigset_t set; sigset_t set;
pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set); pthread_sigmask(SIG_BLOCK, SIGALL_SET, &set);
if (self->dtv && v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) { if (v[0]<=(size_t)self->dtv[0] && self->dtv[v[0]]) {
pthread_sigmask(SIG_SETMASK, &set, 0); pthread_sigmask(SIG_SETMASK, &set, 0);
return (char *)self->dtv[v[0]]+v[1]; return (char *)self->dtv[v[0]]+v[1];
} }
@ -759,10 +759,10 @@ void *__tls_get_addr(size_t *v)
for (p=head; p->tls_id != v[0]; p=p->next); for (p=head; p->tls_id != v[0]; p=p->next);
/* Get new DTV space from new DSO if needed */ /* Get new DTV space from new DSO if needed */
if (!self->dtv || v[0] > (size_t)self->dtv[0]) { if (v[0] > (size_t)self->dtv[0]) {
void **newdtv = p->new_dtv + void **newdtv = p->new_dtv +
(v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1); (v[0]+1)*sizeof(void *)*a_fetch_add(&p->new_dtv_idx,1);
if (self->dtv) memcpy(newdtv, self->dtv, memcpy(newdtv, self->dtv,
((size_t)self->dtv[0]+1) * sizeof(void *)); ((size_t)self->dtv[0]+1) * sizeof(void *));
newdtv[0] = (void *)v[0]; newdtv[0] = (void *)v[0];
self->dtv = newdtv; self->dtv = newdtv;

2
src/thread/pthread_self.c
View File

@ -17,6 +17,8 @@ static int init_main_thread()
main_thread->self = main_thread; main_thread->self = main_thread;
main_thread->tid = main_thread->pid = main_thread->tid = main_thread->pid =
__syscall(SYS_set_tid_address, &main_thread->tid); __syscall(SYS_set_tid_address, &main_thread->tid);
if (!main_thread->dtv)
main_thread->dtv = (void *)dummy;
libc.main_thread = main_thread; libc.main_thread = main_thread;
return 0; return 0;
} }