stats: add fallback to __sync_* functions if __atomic_* ones not available

configure.ac

@@ -486,6 +486,12 @@ AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread_np.h>]], [[cpuset_t set; CPU
 AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <sched.h>]], [[cpuset_t* set = cpuset_create(); cpuset_destroy(set);]])],
 [AC_DEFINE(HAVE_CPUSET_NETBSD, 1, [Define if cpuset_t and cpuset(3) exists.])])
 
+AC_COMPILE_IFELSE(
+  [AC_LANG_PROGRAM([[#include <stdint.h>]],
+                   [[uint64_t val = 0; __atomic_add_fetch(&val, 1, __ATOMIC_RELAXED);]])],
+  [AC_DEFINE(HAVE_ATOMIC, 1, [Define to 1 if you have '__atomic' functions.])]
+)
+
 # Prepare CFLAG_VISIBILITY to be used where needed
 gl_VISIBILITY()
 

src/knot/nameserver/query_module.h

@@ -46,6 +46,14 @@
 #include "knot/nameserver/internet.h"
 #include "contrib/ucw/lists.h"
 
+#ifdef HAVE_ATOMIC
+ #define ATOMIC_ADD(dst, val) __atomic_add_fetch(dst, val, __ATOMIC_RELAXED);
+ #define ATOMIC_SUB(dst, val) __atomic_sub_fetch(dst, val, __ATOMIC_RELAXED);
+#else
+ #define ATOMIC_ADD(dst, val) __sync_fetch_and_add(dst, val);
+ #define ATOMIC_SUB(dst, val) __sync_fetch_and_sub(dst, val);
+#endif
+
 #define MODULE_ERR(mod, msg, ...) \
 	log_error("module '%.*s', " msg, mod[0], mod + 1, ##__VA_ARGS__)
 
@@ -133,7 +141,7 @@ inline static void mod_ctr_incr(mod_ctr_t *stats, uint32_t idx, uint64_t val)
 	mod_ctr_t *ctr = stats + idx;
 	assert(ctr->count == 1);
 
-	__atomic_add_fetch(&ctr->counter, val, __ATOMIC_RELAXED);
+	ATOMIC_ADD(&ctr->counter, val);
 }
 
 inline static void mod_ctr_decr(mod_ctr_t *stats, uint32_t idx, uint64_t val)
@@ -141,7 +149,7 @@ inline static void mod_ctr_decr(mod_ctr_t *stats, uint32_t idx, uint64_t val)
 	mod_ctr_t *ctr = stats + idx;
 	assert(ctr->count == 1);
 
-	__atomic_sub_fetch(&ctr->counter, val, __ATOMIC_RELAXED);
+	ATOMIC_SUB(&ctr->counter, val);
 }
 
 inline static void mod_ctrs_incr(mod_ctr_t *stats, uint32_t idx, uint32_t offset, uint64_t val)
@@ -151,9 +159,9 @@ inline static void mod_ctrs_incr(mod_ctr_t *stats, uint32_t idx, uint32_t offset
 
 	// Increment the last counter if offset overflows.
 	if (offset < ctr->count) {
-		__atomic_add_fetch(&ctr->counters[offset], val, __ATOMIC_RELAXED);
+		ATOMIC_ADD(&ctr->counters[offset], val);
 	} else {
-		__atomic_add_fetch(&ctr->counters[ctr->count - 1], val, __ATOMIC_RELAXED);
+		ATOMIC_ADD(&ctr->counters[ctr->count - 1], val);
 	}
 }
 
@@ -164,9 +172,9 @@ inline static void mod_ctrs_decr(mod_ctr_t *stats, uint32_t idx, uint32_t offset
 
 	// Increment the last counter if offset overflows.
 	if (offset < ctr->count) {
-		__atomic_sub_fetch(&ctr->counters[offset], val, __ATOMIC_RELAXED);
+		ATOMIC_SUB(&ctr->counters[offset], val);
 	} else {
-		__atomic_sub_fetch(&ctr->counters[ctr->count - 1], val, __ATOMIC_RELAXED);
+		ATOMIC_SUB(&ctr->counters[ctr->count - 1], val);
 	}
 }