diff --git a/mold.h b/mold.h
index e3731ff7..8c4bebc9 100644
--- a/mold.h
+++ b/mold.h
@@ -862,13 +862,13 @@ public:
 
   static void print();
 
-  static bool enabled;
+  static inline bool enabled = false;
 
 private:
   std::string_view name;
   std::atomic_uint32_t value;
 
-  static std::vector<Counter *> instances;
+  static inline std::vector<Counter *> instances;
 };
 
 struct TimerRecord {
diff --git a/perf.cc b/perf.cc
index 331fb2a1..d1dedfdf 100644
--- a/perf.cc
+++ b/perf.cc
@@ -5,9 +5,6 @@
 #include <sys/resource.h>
 #include <sys/time.h>
 
-std::vector<Counter *> Counter::instances;
-bool Counter::enabled = false;
-
 void Counter::print() {
   if (!enabled)
     return;