nghttpx: Use thread_local if it is available

configure.ac

@@ -254,6 +254,21 @@ std::atomic_store(&a, p);
     [have_atomic_std_shared_ptr=no
      AC_MSG_RESULT([no])])
 
+# Check that thread_local storage specifier is available
+AC_MSG_CHECKING([whether thread_local storage class specifier is available.])
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+,
+[[
+thread_local int a = 0;
+(void)a;
+]])],
+    [AC_DEFINE([HAVE_THREAD_LOCAL], [1],
+               [Define to 1 if you have thread_local storage specifier.])
+     have_thread_local=yes
+     AC_MSG_RESULT([yes])],
+    [have_Thread_local=no
+     AC_MSG_RESULT([no])])
+
 CXXFLAGS=$save_CXXFLAGS
 
 AC_LANG_POP()

src/shrpx.cc

@@ -3723,7 +3723,7 @@ int main(int argc, char **argv) {
 
   LOG(NOTICE) << "Shutdown momentarily";
 
-  delete log_config();
+  delete_log_config();
 
   return 0;
 }

src/shrpx_log_config.cc

@@ -33,12 +33,24 @@ LogConfig::LogConfig()
     : accesslog_fd(-1), errorlog_fd(-1), errorlog_tty(false) {}
 
 #ifndef NOTHREADS
-static pthread_key_t lckey;
-static pthread_once_t lckey_once = PTHREAD_ONCE_INIT;
+#ifdef HAVE_THREAD_LOCAL
+namespace {
+thread_local std::unique_ptr<LogConfig> config = make_unique<LogConfig>();
+} // namespace
 
-static void make_key(void) { pthread_key_create(&lckey, NULL); }
+LogConfig *log_config() { return config.get(); }
+void delete_log_config() {}
+#else  // !HAVE_THREAD_LOCAL
+namespace {
+pthread_key_t lckey;
+pthread_once_t lckey_once = PTHREAD_ONCE_INIT;
+} // namespace
 
-LogConfig *log_config(void) {
+namespace {
+void make_key() { pthread_key_create(&lckey, NULL); }
+} // namespace
+
+LogConfig *log_config() {
   pthread_once(&lckey_once, make_key);
   LogConfig *config = (LogConfig *)pthread_getspecific(lckey);
   if (!config) {
@@ -47,9 +59,17 @@ LogConfig *log_config(void) {
   }
   return config;
 }
-#else
-static LogConfig *config = new LogConfig();
-LogConfig *log_config(void) { return config; }
+
+void delete_log_config() { delete log_config(); }
+#endif // !HAVE_THREAD_LOCAL
+#else  // NOTHREADS
+namespace {
+std::unique_ptr<LogConfig> config = make_unique<LogConfig>();
+} // namespace
+
+LogConfig *log_config() { return config.get(); }
+
+void delete_log_config() {}
 #endif // NOTHREADS
 
 void LogConfig::update_tstamp(

src/shrpx_log_config.h

@@ -54,7 +54,10 @@ struct LogConfig {
 
 // We need LogConfig per thread to avoid data race around opening file
 // descriptor for log files.
-extern LogConfig *log_config(void);
+LogConfig *log_config();
+
+// Deletes log_config
+void delete_log_config();
 
 } // namespace shrpx