diff --git a/sim/debug.cc b/sim/debug.cc
index 09c604a951..b73ab42458 100644
--- a/sim/debug.cc
+++ b/sim/debug.cc
@@ -40,11 +40,13 @@
 
 using namespace std;
 
+#ifdef DEBUG
 void
 debug_break()
 {
     kill(getpid(), SIGTRAP);
 }
+#endif
 
 //
 // Debug event: place a breakpoint on the process function and
diff --git a/sim/debug.hh b/sim/debug.hh
index eb0be772e1..a4f8b8702d 100644
--- a/sim/debug.hh
+++ b/sim/debug.hh
@@ -29,6 +29,10 @@
 #ifndef __DEBUG_HH__
 #define __DEBUG_HH__
 
+#ifdef DEBUG
 void debug_break();
+#else
+inline void debug_break() { }
+#endif
 
 #endif // __DEBUG_HH__