Use GCC atomic builtin operations.

Fix for bug #531902.

configure.in

@@ -2412,7 +2412,22 @@ dnl ********************************
 
 AC_MSG_CHECKING([whether to use assembler code for atomic operations])
 
+glib_cv_gcc_has_builtin_atomic_operations=no
 if test x"$GCC" = xyes; then
+  AC_MSG_CHECKING([whether GCC supports build-in atomic intrinsics])
+  AC_TRY_LINK([],
+	      [int i;
+	       __sync_synchronize ();
+	       __sync_bool_compare_and_swap (&i, 0, 1);
+	       __sync_fetch_and_add (&i, 1);
+	      ],
+	      [glib_cv_gcc_has_builtin_atomic_operations=yes],
+	      [glib_cv_gcc_has_builtin_atomic_operations=no])
+
+  AC_MSG_RESULT($glib_cv_gcc_has_builtin_atomic_operations)
+  if test $glib_cv_gcc_has_builtin_atomic_operations = yes; then
+    glib_memory_barrier_needed=yes
+  else
     case $host_cpu in
       i386)
         AC_MSG_RESULT([none])
@@ -2509,6 +2524,7 @@ if test x"$GCC" = xyes; then
         glib_memory_barrier_needed=yes
         ;;
     esac
+  fi
 else
   if test $glib_native_win32 = yes; then
     # For Windows but not using gcc. No barriers needed then either.
@@ -2516,6 +2532,9 @@ else
   fi
 fi
 
+AM_CONDITIONAL(HAVE_GCC_BUILTINS_FOR_ATOMIC_OPERATIONS,
+	       [test $glib_cv_gcc_has_builtin_atomic_operations = yes])
+
 dnl ****************************************
 dnl *** GLib POLL* compatibility defines ***
 dnl ****************************************

glib/Makefile.am

@@ -19,6 +19,12 @@ gregex_c =
 gregex_h =
 endif
 
+if HAVE_GCC_BUILTINS_FOR_ATOMIC_OPERATIONS
+gatomic_c = gatomic-gcc.c
+else
+gatomic_c = gatomic.c
+endif
+
 SUBDIRS = libcharset $(PRINTF_SUBDIR) $(MAYBE_PCRE) update-pcre . tests
 
 DIST_SUBDIRS = libcharset gnulib pcre update-pcre tests
@@ -100,7 +106,7 @@ uninstall-ms-lib:
 libglib_2_0_la_SOURCES = 	\
 	garray.c		\
 	gasyncqueue.c		\
-	gatomic.c		\
+	$(gatomic_c)		\
 	gbacktrace.c		\
 	gbase64.c		\
 	gbookmarkfile.c 	\

glib/gatomic-gcc.c

@@ -0,0 +1,92 @@
+/* GLIB - Library of useful routines for C programming
+ * gatomic-gcc.c: atomic operations using GCC builtins.
+ * Copyright (C) 2009 Hiroyuki Ikezoe
+ *
+ * This 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 of the License, or (at your option) any later version.
+ *
+ * This 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 this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include "glib.h"
+#include "galias.h"
+
+gint
+g_atomic_int_exchange_and_add (volatile gint G_GNUC_MAY_ALIAS *atomic,
+			       gint           val)
+{
+  return __sync_fetch_and_add (atomic, val);
+}
+
+void
+g_atomic_int_add (volatile gint G_GNUC_MAY_ALIAS *atomic,
+		  gint val)
+{
+  __sync_fetch_and_add (atomic, val);
+}
+
+gboolean
+g_atomic_int_compare_and_exchange (volatile gint G_GNUC_MAY_ALIAS *atomic,
+				   gint           oldval,
+				   gint           newval)
+{
+  return __sync_bool_compare_and_swap (atomic, oldval, newval);
+}
+
+gboolean
+g_atomic_pointer_compare_and_exchange (volatile gpointer G_GNUC_MAY_ALIAS *atomic,
+				       gpointer           oldval,
+				       gpointer           newval)
+{
+  return __sync_bool_compare_and_swap (atomic, oldval, newval);
+}
+
+void
+_g_atomic_thread_init (void)
+{
+}
+
+gint
+(g_atomic_int_get) (volatile gint G_GNUC_MAY_ALIAS *atomic)
+{
+  __sync_synchronize ();
+  return *atomic;
+}
+
+void
+(g_atomic_int_set) (volatile gint G_GNUC_MAY_ALIAS *atomic,
+		    gint           newval)
+{
+  *atomic = newval;
+  __sync_synchronize ();
+}
+
+gpointer
+(g_atomic_pointer_get) (volatile gpointer G_GNUC_MAY_ALIAS *atomic)
+{
+  __sync_synchronize ();
+  return *atomic;
+}
+
+void
+(g_atomic_pointer_set) (volatile gpointer G_GNUC_MAY_ALIAS *atomic,
+			gpointer           newval)
+{
+  *atomic = newval;
+  __sync_synchronize ();
+}
+
+#define __G_ATOMIC_C__
+#include "galiasdef.c"