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[PATCH v8 3/8] nptl: Add C11 threads call_once functions
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Fri, 2 Feb 2018 15:04:39 -0200
- Subject: [PATCH v8 3/8] nptl: Add C11 threads call_once functions
- Authentication-results: sourceware.org; auth=none
- References: <1517591084-11347-1-git-send-email-adhemerval.zanella@linaro.org>
This patch adds the call_* definitions from C11 threads (ISO/IEC 9899:2011),
more specifically call_once and required types.
Mostly of the definitions are composed based on POSIX conterparts,including
once_flag (pthread_once_t). The idea is to make possible to share POSIX
internal implementations for mostly of the code (and making adjustment only
when required).
Checked with a build for all major ABI (aarch64-linux-gnu, alpha-linux-gnu,
arm-linux-gnueabi, i386-linux-gnu, ia64-linux-gnu, m68k-linux-gnu,
microblaze-linux-gnu [1], mips{64}-linux-gnu, nios2-linux-gnu,
powerpc{64le}-linux-gnu, s390{x}-linux-gnu, sparc{64}-linux-gnu,
tile{pro,gx}-linux-gnu, and x86_64-linux-gnu).
Also ran a full check on aarch64-linux-gnu, x86_64-linux-gnu, i686-linux-gnu,
arm-linux-gnueabhf, and powerpc64le-linux-gnu.
* conform/data/threads.h-data (ONCE_FLAG_INIT): New macro.
(once_flag): New type.
(call_once): New function.
* nptl/Makefile (libpthread-routines): Add call_once object.
* nptl/Versions (libphread) [GLIBC_2.27]: Add call_once symbol.
* nptl/call_once.c: New file.
* sysdeps/nptl/threads.h (ONCE_FLAG_INIT): New define.
(once_flag): New type.
(call_once): New prototype.
---
ChangeLog | 10 ++++++++++
conform/data/threads.h-data | 5 +++++
nptl/Makefile | 2 +-
nptl/Versions | 2 +-
nptl/call_once.c | 31 +++++++++++++++++++++++++++++++
sysdeps/nptl/threads.h | 8 ++++++++
6 files changed, 56 insertions(+), 2 deletions(-)
create mode 100644 nptl/call_once.c
diff --git a/conform/data/threads.h-data b/conform/data/threads.h-data
index bb5ca75..70b2fe0 100644
--- a/conform/data/threads.h-data
+++ b/conform/data/threads.h-data
@@ -1,5 +1,7 @@
#if defined ISO11
+macro ONCE_FLAG_INIT
+
constant thrd_success
constant thrd_busy
constant thrd_error
@@ -13,6 +15,7 @@ constant mtx_timed
type thrd_t
type thrd_start_t
type mtx_t
+type once_flag
function int thrd_create (thrd_t*, thrd_start_t, void*)
function int thrd_equal (thrd_t, thrd_t)
@@ -30,6 +33,8 @@ function int mtx_trylock (mtx_t*)
function int mtx_unlock (mtx_t*)
function void mtx_destroy (mtx_t*)
+function void call_once (once_flag*, void (*)(void))
+
#include "time.h-data"
#endif
diff --git a/nptl/Makefile b/nptl/Makefile
index 1b8a6a8..e539df8 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -143,7 +143,7 @@ libpthread-routines = nptl-init vars events version pt-interp \
thrd_create thrd_current thrd_detach thrd_equal \
thrd_exit thrd_join thrd_sleep thrd_yield \
mtx_destroy mtx_init mtx_lock mtx_timedlock \
- mtx_trylock mtx_unlock
+ mtx_trylock mtx_unlock call_once
# pthread_setuid pthread_seteuid pthread_setreuid \
# pthread_setresuid \
# pthread_setgid pthread_setegid pthread_setregid \
diff --git a/nptl/Versions b/nptl/Versions
index a1969e3..f09e295 100644
--- a/nptl/Versions
+++ b/nptl/Versions
@@ -269,7 +269,7 @@ libpthread {
GLIBC_2.28 {
thrd_create; thrd_current; thrd_detach; thrd_equal; thrd_exit; thrd_join;
thrd_sleep; thrd_yield; mtx_init; mtx_lock; mtx_timedlock; mtx_trylock;
- mtx_unlock; mtx_destroy;
+ mtx_unlock; mtx_destroy; call_once;
}
GLIBC_PRIVATE {
diff --git a/nptl/call_once.c b/nptl/call_once.c
new file mode 100644
index 0000000..d66d728
--- /dev/null
+++ b/nptl/call_once.c
@@ -0,0 +1,31 @@
+/* C11 threads call once implementation.
+ Copyright (C) 2018 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
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <stdalign.h>
+
+#include "thrd_priv.h"
+
+void
+call_once (once_flag *flag, void (*func)(void))
+{
+ _Static_assert (sizeof (once_flag) == sizeof (pthread_once_t),
+ "once_flag size");
+ _Static_assert (alignof (once_flag) == alignof (pthread_once_t),
+ "once_flag alignment");
+ __pthread_once (flag, func);
+}
diff --git a/sysdeps/nptl/threads.h b/sysdeps/nptl/threads.h
index 42d9b5c..6c9c3ef 100644
--- a/sysdeps/nptl/threads.h
+++ b/sysdeps/nptl/threads.h
@@ -27,8 +27,11 @@ __BEGIN_DECLS
#include <bits/pthreadtypes-arch.h>
#include <bits/types/struct_timespec.h>
+#define ONCE_FLAG_INIT 0
+
typedef unsigned long int thrd_t;
typedef int (*thrd_start_t) (void*);
+typedef int __ONCE_ALIGNMENT once_flag;
/* Exit and error codes. */
enum
@@ -129,6 +132,11 @@ extern int mtx_unlock (mtx_t *__mutex);
/* Destroy the mutex object pointed by __MUTEX. */
extern void mtx_destroy (mtx_t *__mutex);
+
+/* Call function __FUNC exactly once, even if invoked from several threads.
+ All calls must be made with the same __FLAGS object. */
+extern void call_once (once_flag *__flag, void (*__func)(void));
+
__END_DECLS
#endif /* _THREADS_H */
--
2.7.4