Use __thread keyword if available

5 files changed, 53 insertions, 3 deletions

diff --git a/configure.ac b/configure.ac
index c1e7cfa..eb71db7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -36,6 +36,8 @@ AS_IF([test x$threads = xnone], AC_DEFINE([ODB_THREADS_NONE], [1], [Have no thre
 AS_IF([test x$threads = xwin32], AC_DEFINE([ODB_THREADS_WIN32], [1], [Have Win32 threads.]))
 AS_IF([test x$threads = xposix], AC_DEFINE([ODB_THREADS_POSIX], [1], [Have POSIX threads.]))
 
+AS_IF([test x$threads_thread_keyword = xyes], AC_DEFINE([ODB_THREADS_TLS_KEYWORD], [1], [Have __thread keyword.]))
+
 # Define LIBODB_STATIC_LIB if we are build static library on certain platforms.
 #
 STATIC_LIB([LIBODB_STATIC_LIB], [Static library interface.])
diff --git a/m4/threads.m4 b/m4/threads.m4
index 7c32abe..ea547c0 100644
--- a/m4/threads.m4
+++ b/m4/threads.m4
@@ -5,6 +5,8 @@ dnl license   : GNU GPL v2; see accompanying LICENSE file
 dnl
 AC_DEFUN([THREADS],[
 
+threads_thread_keyword=no
+
 AC_ARG_ENABLE(
   [threads],
   AS_HELP_STRING([--disable-threads], [disable threads (enabled by default)]),
@@ -30,6 +32,24 @@ if test x$threads = xcheck; then
         threads=posix
         LIBS="$LIBS $PTHREAD_LIBS"
         CXXFLAGS="$CXXFLAGS $PTHREAD_CXXFLAGS"
+
+        # Check if we can use the __thread keyword.
+        #
+        AC_MSG_CHECKING([for __thread keyword])
+
+        CXX_LIBTOOL_LINK_IFELSE(
+          AC_LANG_SOURCE([[
+            __thread int tls_var;
+
+            int
+            main ()
+            {
+              tls_var = 0;
+            }
+          ]]),
+          [threads_thread_keyword=yes])
+
+        AC_MSG_RESULT([$threads_thread_keyword])
       fi
       ;;
   esac
diff --git a/odb/Makefile.am b/odb/Makefile.am
index 9922a37..d671b16 100644
--- a/odb/Makefile.am
+++ b/odb/Makefile.am
@@ -22,5 +22,5 @@ libodb_la_SOURCES += __path__(win32_sources) __path__(win32_dll_sources)
 nobase_odbinclude_HEADERS += __path__(win32_headers)
 endif
 
-libodb_la_CPPFLAGS= -I'$(top_builddir)' -I'$(top_srcdir)' -DLIBODB_DYNAMIC_LIB
-libodb_la_LDFLAGS = -release __value__(interface_version) -no-undefined
+AM_CPPFLAGS= -I'$(top_builddir)' -I'$(top_srcdir)' -DLIBODB_DYNAMIC_LIB
+AM_LDFLAGS = -release __value__(interface_version) -no-undefined
diff --git a/odb/details/config.h.in b/odb/details/config.h.in
index a55352a..acab724 100644
--- a/odb/details/config.h.in
+++ b/odb/details/config.h.in
@@ -12,6 +12,8 @@
 #undef ODB_THREADS_NONE
 #undef ODB_THREADS_POSIX
 #undef ODB_THREADS_WIN32
+#undef ODB_THREADS_TLS_KEYWORD
+#undef ODB_THREADS_TLS_DECLSPEC
 
 #undef LIBODB_STATIC_LIB
 
diff --git a/odb/details/tls.hxx b/odb/details/tls.hxx
index 2ed68ab..2c19081 100644
--- a/odb/details/tls.hxx
+++ b/odb/details/tls.hxx
@@ -54,7 +54,33 @@ namespace odb
 #elif defined(ODB_THREADS_POSIX)
 
 #  include <odb/details/posix/tls.hxx>
-#  define ODB_TLS_POINTER(type) tls<type*>
+
+#  ifdef ODB_THREADS_TLS_KEYWORD
+#    define ODB_TLS_POINTER(type) __thread type*
+
+namespace odb
+{
+  namespace details
+  {
+    template <typename T>
+    inline T*
+    tls_get (T* p)
+    {
+      return p;
+    }
+
+    template <typename T>
+    inline void
+    tls_set (T*& rp, T* p)
+    {
+      rp = p;
+    }
+  }
+}
+
+#  else
+#    define ODB_TLS_POINTER(type) tls<type*>
+#  endif
 #  define ODB_TLS_OBJECT(type) tls<type>
 
 #elif defined(ODB_THREADS_WIN32)