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authorUlrich Drepper <drepper@gmail.com>2012-01-30 22:32:05 -0500
committerUlrich Drepper <drepper@gmail.com>2012-01-30 22:32:05 -0500
commit27a25b6e633a3ea071e229337eaae36d0fa243fa (patch)
tree21c06c84309990fa6f380dd84bc18a7fc95b55e1 /elf/dl-tls.c
parent96bc5b45a671de1e266b841edba2516afc46d84a (diff)
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Optimize __get_tls_addr a bit
Rearrange code to avoid creation of a stack frame. At least on x86-64 the code for the fast path should be down to the bare minimum.
Diffstat (limited to 'elf/dl-tls.c')
-rw-r--r--elf/dl-tls.c44
1 files changed, 28 insertions, 16 deletions
diff --git a/elf/dl-tls.c b/elf/dl-tls.c
index ea94aa0..4358616 100644
--- a/elf/dl-tls.c
+++ b/elf/dl-tls.c
@@ -1,5 +1,5 @@
/* Thread-local storage handling in the ELF dynamic linker. Generic version.
- Copyright (C) 2002-2006,2008,2011 Free Software Foundation, Inc.
+ Copyright (C) 2002-2006,2008,2011,2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -509,6 +509,7 @@ rtld_hidden_def (_dl_deallocate_tls)
of the following macros. */
# ifndef GET_ADDR_ARGS
# define GET_ADDR_ARGS tls_index *ti
+# define GET_ADDR_PARAM ti
# endif
# ifndef GET_ADDR_MODULE
# define GET_ADDR_MODULE ti->ti_module
@@ -690,13 +691,13 @@ _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)
+tls_get_addr_tail (GET_ADDR_ARGS, dtv_t *dtv, struct link_map *the_map)
{
/* The allocation was deferred. Do it now. */
if (the_map == NULL)
{
/* Find the link map for this module. */
- size_t idx = module;
+ size_t idx = GET_ADDR_MODULE;
struct dtv_slotinfo_list *listp = GL(dl_tls_dtv_slotinfo_list);
while (idx >= listp->len)
@@ -728,18 +729,34 @@ tls_get_addr_tail (dtv_t *dtv, struct link_map *the_map, size_t module)
if (__builtin_expect (the_map->l_tls_offset
!= FORCED_DYNAMIC_TLS_OFFSET, 1))
{
- void *p = dtv[module].pointer.val;
+ void *p = dtv[GET_ADDR_MODULE].pointer.val;
if (__builtin_expect (p == TLS_DTV_UNALLOCATED, 0))
goto again;
- return p;
+ return (char *) p + GET_ADDR_OFFSET;
}
}
}
- void *p = dtv[module].pointer.val = allocate_and_init (the_map);
- dtv[module].pointer.is_static = false;
+ void *p = dtv[GET_ADDR_MODULE].pointer.val = allocate_and_init (the_map);
+ dtv[GET_ADDR_MODULE].pointer.is_static = false;
- return p;
+ return (char *) p + GET_ADDR_OFFSET;
+}
+
+
+static struct link_map *
+__attribute_noinline__
+update_get_addr (GET_ADDR_ARGS)
+{
+ struct link_map *the_map = _dl_update_slotinfo (GET_ADDR_MODULE);
+ dtv_t *dtv = THREAD_DTV ();
+
+ void *p = dtv[GET_ADDR_MODULE].pointer.val;
+
+ if (__builtin_expect (p == TLS_DTV_UNALLOCATED, 0))
+ return tls_get_addr_tail (GET_ADDR_PARAM, dtv, the_map);
+
+ return (char *) p + GET_ADDR_OFFSET;
}
@@ -749,19 +766,14 @@ void *
__tls_get_addr (GET_ADDR_ARGS)
{
dtv_t *dtv = THREAD_DTV ();
- struct link_map *the_map = NULL;
- void *p;
if (__builtin_expect (dtv[0].counter != GL(dl_tls_generation), 0))
- {
- the_map = _dl_update_slotinfo (GET_ADDR_MODULE);
- dtv = THREAD_DTV ();
- }
+ return update_get_addr (GET_ADDR_PARAM);
- p = dtv[GET_ADDR_MODULE].pointer.val;
+ void *p = dtv[GET_ADDR_MODULE].pointer.val;
if (__builtin_expect (p == TLS_DTV_UNALLOCATED, 0))
- p = tls_get_addr_tail (dtv, the_map, GET_ADDR_MODULE);
+ return tls_get_addr_tail (GET_ADDR_PARAM, dtv, NULL);
return (char *) p + GET_ADDR_OFFSET;
}