Index: lib/xray/xray_x86_64.cc
===================================================================
--- lib/xray/xray_x86_64.cc
+++ lib/xray/xray_x86_64.cc
@@ -6,6 +6,8 @@
 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
 #include <sys/types.h>
 #include <sys/sysctl.h>
+#elif SANITIZER_MAC
+#include <mach/mach_time.h>
 #endif
 
 #include <atomic>
@@ -92,6 +94,18 @@
     return 0;
     
 }
+#elif SANITIZER_MAC
+static mach_timebase_info_data_t TimebaseInfo;
+
+uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
+    if (TimebaseInfo.denom == 0) {
+      mach_timebase_info(&TimebaseInfo);
+    }
+    uint64_t currentTime = mach_absolute_time();
+    currentTime *= TimebaseInfo.numer;
+    currentTime /= TimebaseInfo.denom;
+    return currentTime;
+}
 #else
 uint64_t getTSCFrequency() XRAY_NEVER_INSTRUMENT {
     /* Not supported */