Use glibc_likely instead __builtin_expect.

[thirdparty/glibc.git] / nptl / sysdeps / pthread / unwind-forcedunwind.c

diff --git a/nptl/sysdeps/pthread/unwind-forcedunwind.c b/nptl/sysdeps/pthread/unwind-forcedunwind.c
index b0f848708698ed462466a0ebb967f5a69cf92cfd..9d7bdc5b90d015388da5ad1995dc15dec6358995 100644 (file)
--- a/nptl/sysdeps/pthread/unwind-forcedunwind.c
+++ b/nptl/sysdeps/pthread/unwind-forcedunwind.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2003-2014 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Jakub Jelinek <jakub@redhat.com>.
 
@@ -13,15 +13,17 @@
    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; see the file COPYING.LIB.  If not,
-   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   License along with the GNU C Library; see the file COPYING.LIB.  If
+   not, see <http://www.gnu.org/licenses/>.  */
 
 #include <dlfcn.h>
 #include <stdio.h>
 #include <unwind.h>
 #include <pthreadP.h>
+#include <sysdep.h>
+#include <gnu/lib-names.h>
 
+static void *libgcc_s_handle;
 static void (*libgcc_s_resume) (struct _Unwind_Exception *exc);
 static _Unwind_Reason_Code (*libgcc_s_personality)
   (int, _Unwind_Action, _Unwind_Exception_Class, struct _Unwind_Exception *,
@@ -31,15 +33,23 @@ static _Unwind_Reason_Code (*libgcc_s_forcedunwind)
 static _Unwind_Word (*libgcc_s_getcfa) (struct _Unwind_Context *);
 
 void
+__attribute_noinline__
 pthread_cancel_init (void)
 {
-  void *resume, *personality, *forcedunwind, *getcfa;
+  void *resume;
+  void *personality;
+  void *forcedunwind;
+  void *getcfa;
   void *handle;
 
-  if (__builtin_expect (libgcc_s_getcfa != NULL, 1))
-    return;
+  if (__glibc_likely (libgcc_s_handle != NULL))
+    {
+      /* Force gcc to reload all values.  */
+      asm volatile ("" ::: "memory");
+      return;
+    }
 
-  handle = __libc_dlopen ("libgcc_s.so.1");
+  handle = __libc_dlopen (LIBGCC_S_SO);
 
   if (handle == NULL
       || (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
@@ -51,47 +61,91 @@ pthread_cancel_init (void)
       || ARCH_CANCEL_INIT (handle)
 #endif
       )
-    __libc_fatal ("libgcc_s.so.1 must be installed for pthread_cancel to work\n");
+    __libc_fatal (LIBGCC_S_SO " must be installed for pthread_cancel to work\n");
 
+  PTR_MANGLE (resume);
   libgcc_s_resume = resume;
+  PTR_MANGLE (personality);
   libgcc_s_personality = personality;
+  PTR_MANGLE (forcedunwind);
   libgcc_s_forcedunwind = forcedunwind;
+  PTR_MANGLE (getcfa);
   libgcc_s_getcfa = getcfa;
+  /* Make sure libgcc_s_handle is written last.  Otherwise,
+     pthread_cancel_init might return early even when the pointer the
+     caller is interested in is not initialized yet.  */
+  atomic_write_barrier ();
+  libgcc_s_handle = handle;
+}
+
+void
+__libc_freeres_fn_section
+__unwind_freeres (void)
+{
+  void *handle = libgcc_s_handle;
+  if (handle != NULL)
+    {
+      libgcc_s_handle = NULL;
+      __libc_dlclose (handle);
+    }
 }
 
 void
 _Unwind_Resume (struct _Unwind_Exception *exc)
 {
-  if (__builtin_expect (libgcc_s_resume == NULL, 0))
+  if (__glibc_unlikely (libgcc_s_handle == NULL))
     pthread_cancel_init ();
-  libgcc_s_resume (exc);
+  else
+    atomic_read_barrier ();
+
+  void (*resume) (struct _Unwind_Exception *exc) = libgcc_s_resume;
+  PTR_DEMANGLE (resume);
+  resume (exc);
 }
 
 _Unwind_Reason_Code
 __gcc_personality_v0 (int version, _Unwind_Action actions,
                      _Unwind_Exception_Class exception_class,
-                      struct _Unwind_Exception *ue_header,
-                      struct _Unwind_Context *context)
+                     struct _Unwind_Exception *ue_header,
+                     struct _Unwind_Context *context)
 {
-  if (__builtin_expect (libgcc_s_personality == NULL, 0))
+  if (__glibc_unlikely (libgcc_s_handle == NULL))
     pthread_cancel_init ();
-  return libgcc_s_personality (version, actions, exception_class,
-                              ue_header, context);
+  else
+    atomic_read_barrier ();
+
+  _Unwind_Reason_Code (*personality)
+    (int, _Unwind_Action, _Unwind_Exception_Class, struct _Unwind_Exception *,
+     struct _Unwind_Context *) = libgcc_s_personality;
+  PTR_DEMANGLE (personality);
+  return personality (version, actions, exception_class, ue_header, context);
 }
 
 _Unwind_Reason_Code
 _Unwind_ForcedUnwind (struct _Unwind_Exception *exc, _Unwind_Stop_Fn stop,
                      void *stop_argument)
 {
-  if (__builtin_expect (libgcc_s_forcedunwind == NULL, 0))
+  if (__glibc_unlikely (libgcc_s_handle == NULL))
     pthread_cancel_init ();
-  return libgcc_s_forcedunwind (exc, stop, stop_argument);
+  else
+    atomic_read_barrier ();
+
+  _Unwind_Reason_Code (*forcedunwind)
+    (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *)
+    = libgcc_s_forcedunwind;
+  PTR_DEMANGLE (forcedunwind);
+  return forcedunwind (exc, stop, stop_argument);
 }
 
 _Unwind_Word
 _Unwind_GetCFA (struct _Unwind_Context *context)
 {
-  if (__builtin_expect (libgcc_s_getcfa == NULL, 0))
+  if (__glibc_unlikely (libgcc_s_handle == NULL))
     pthread_cancel_init ();
-  return libgcc_s_getcfa (context);
+  else
+    atomic_read_barrier ();
+
+  _Unwind_Word (*getcfa) (struct _Unwind_Context *) = libgcc_s_getcfa;
+  PTR_DEMANGLE (getcfa);
+  return getcfa (context);
 }