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* elf/dl-tls.c (__tls_get_addr): Optimize by moving slow path in

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its own function.  This reduces the frame setup costs and more.
This commit is contained in:
Ulrich Drepper 2008-05-12 05:36:02 +00:00
parent a7eb802f11
commit a3636e8b89
2 changed files with 61 additions and 43 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2008-05-11 Ulrich Drepper <drepper@redhat.com>
* elf/dl-tls.c (__tls_get_addr): Optimize by moving slow path in
its own function. This reduces the frame setup costs and more.
2008-02-11 Joseph Myers <joseph@codesourcery.com>
[BZ #3406]

99
elf/dl-tls.c
View File

@ -691,6 +691,61 @@ _dl_update_slotinfo (unsigned long int req_modid)
}
static void *
__attribute_noinline__
tls_get_addr_tail (dtv_t *dtv, struct link_map *the_map, size_t module)
{
/* The allocation was deferred. Do it now. */
if (the_map == NULL)
{
/* Find the link map for this module. */
size_t idx = module;
struct dtv_slotinfo_list *listp = GL(dl_tls_dtv_slotinfo_list);
while (idx >= listp->len)
{
idx -= listp->len;
listp = listp->next;
}
the_map = listp->slotinfo[idx].map;
}
again:
/* Make sure that, if a dlopen running in parallel forces the
variable into static storage, we'll wait until the address in the
static TLS block is set up, and use that. If we're undecided
yet, make sure we make the decision holding the lock as well. */
if (__builtin_expect (the_map->l_tls_offset
!= FORCED_DYNAMIC_TLS_OFFSET, 0))
{
__rtld_lock_lock_recursive (GL(dl_load_lock));
if (__builtin_expect (the_map->l_tls_offset == NO_TLS_OFFSET, 1))
{
the_map->l_tls_offset = FORCED_DYNAMIC_TLS_OFFSET;
__rtld_lock_unlock_recursive (GL(dl_load_lock));
}
else
{
__rtld_lock_unlock_recursive (GL(dl_load_lock));
if (__builtin_expect (the_map->l_tls_offset
!= FORCED_DYNAMIC_TLS_OFFSET, 1))
{
void *p = dtv[module].pointer.val;
if (__builtin_expect (p == TLS_DTV_UNALLOCATED, 0))
goto again;
return p;
}
}
}
void *p = dtv[module].pointer.val = allocate_and_init (the_map);
dtv[module].pointer.is_static = false;
return p;
}
/* The generic dynamic and local dynamic model cannot be used in
statically linked applications. */
void *
@ -703,52 +758,10 @@ __tls_get_addr (GET_ADDR_ARGS)
if (__builtin_expect (dtv[0].counter != GL(dl_tls_generation), 0))
the_map = _dl_update_slotinfo (GET_ADDR_MODULE);
retry:
p = dtv[GET_ADDR_MODULE].pointer.val;
if (__builtin_expect (p == TLS_DTV_UNALLOCATED, 0))
{
/* The allocation was deferred. Do it now. */
if (the_map == NULL)
{
/* Find the link map for this module. */
size_t idx = GET_ADDR_MODULE;
struct dtv_slotinfo_list *listp = GL(dl_tls_dtv_slotinfo_list);
while (idx >= listp->len)
{
idx -= listp->len;
listp = listp->next;
}
the_map = listp->slotinfo[idx].map;
}
/* Make sure that, if a dlopen running in parallel forces the
variable into static storage, we'll wait until the address in
the static TLS block is set up, and use that. If we're
undecided yet, make sure we make the decision holding the
lock as well. */
if (__builtin_expect (the_map->l_tls_offset
!= FORCED_DYNAMIC_TLS_OFFSET, 0))
{
__rtld_lock_lock_recursive (GL(dl_load_lock));
if (__builtin_expect (the_map->l_tls_offset == NO_TLS_OFFSET, 1))
{
the_map->l_tls_offset = FORCED_DYNAMIC_TLS_OFFSET;
__rtld_lock_unlock_recursive (GL(dl_load_lock));
}
else
{
__rtld_lock_unlock_recursive (GL(dl_load_lock));
if (__builtin_expect (the_map->l_tls_offset
!= FORCED_DYNAMIC_TLS_OFFSET, 1))
goto retry;
}
}
p = dtv[GET_ADDR_MODULE].pointer.val = allocate_and_init (the_map);
dtv[GET_ADDR_MODULE].pointer.is_static = false;
}
p = tls_get_addr_tail (dtv, the_map, GET_ADDR_MODULE);
return (char *) p + GET_ADDR_OFFSET;
}