AC_CHECK_FUNCS(backtrace)
AC_CHECK_FUNCS(dladdr)
+AC_MSG_CHECKING([for gcc atomic operations])
+AC_TRY_RUN(
+[
+ int main() {
+ volatile int ref = 1;
+ __sync_fetch_and_add (&ref, 1);
+ __sync_sub_and_fetch (&ref, 1);
+ /* Make sure test fails if operations are not supported */
+ __sync_val_compare_and_swap(&ref, 1, 0);
+ return ref;
+ }
+],
+[AC_MSG_RESULT([yes]); AC_DEFINE(HAVE_GCC_ATOMIC_OPERATIONS)],
+[AC_MSG_RESULT([no])])
+
if test x$gmp = xtrue; then
AC_HAVE_LIBRARY([gmp],[LIBS="$LIBS"],[AC_MSG_ERROR([GNU Multi Precision library gmp not found])])
AC_MSG_CHECKING([gmp.h version >= 4.1.4])
#include <sys/stat.h>
#include <string.h>
-#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
#include <dirent.h>
{
}
+#ifndef HAVE_GCC_ATOMIC_OPERATIONS
+#include <pthread.h>
+
/**
- * We use a single mutex for all refcount variables. This
- * is not optimal for performance, but the critical section
- * is not that long...
- * TODO: Consider to include a mutex in each refcount_t variable.
+ * We use a single mutex for all refcount variables.
*/
static pthread_mutex_t ref_mutex = PTHREAD_MUTEX_INITIALIZER;
/**
- * Described in header.
- *
- * TODO: May be implemented with atomic CPU instructions
- * instead of a mutex.
+ * Increase refcount
*/
void ref_get(refcount_t *ref)
{
}
/**
- * Described in header.
- *
- * TODO: May be implemented with atomic CPU instructions
- * instead of a mutex.
+ * Decrease refcount
*/
bool ref_put(refcount_t *ref)
{
pthread_mutex_unlock(&ref_mutex);
return !more_refs;
}
+#endif /* HAVE_GCC_ATOMIC_OPERATIONS */
/**
* output handler in printf() for time_t
*/
typedef volatile u_int refcount_t;
+
+#ifdef HAVE_GCC_ATOMIC_OPERATIONS
+
+#define ref_get(ref) {__sync_fetch_and_add(ref, 1); }
+#define ref_put(ref) (!__sync_sub_and_fetch(ref, 1))
+
+#else /* !HAVE_GCC_ATOMIC_OPERATIONS */
+
/**
* Get a new reference.
*
*/
bool ref_put(refcount_t *ref);
+#endif /* HAVE_GCC_ATOMIC_OPERATIONS */
+
/**
* Get printf hooks for time.
*