diff --git a/js/src/jsscript.cpp b/js/src/jsscript.cpp
index e96ffa5ce68..b8a869236bf 100644
--- a/js/src/jsscript.cpp
+++ b/js/src/jsscript.cpp
@@ -757,6 +757,15 @@ JSPCCounters::init(JSContext *cx, size_t numBytecodes)
     return true;
 }
 
+void
+JSPCCounters::destroy(JSContext *cx)
+{
+    if (counts) {
+        cx->free_(counts);
+        counts = NULL;
+    }
+}
+
 static void
 script_finalize(JSContext *cx, JSObject *obj)
 {
@@ -1499,6 +1508,8 @@ DestroyScript(JSContext *cx, JSScript *script)
 #endif
     JS_REMOVE_LINK(&script->links);
 
+    script->pcCounters.destroy(cx);
+
     cx->free_(script);
 }
 
diff --git a/js/src/jsscript.h b/js/src/jsscript.h
index 0aa486fbb91..3f0cecc013b 100644
--- a/js/src/jsscript.h
+++ b/js/src/jsscript.h
@@ -404,10 +404,11 @@ class JSPCCounters {
     }
 
     ~JSPCCounters() {
-        js::UnwantedForeground::free_(counts);
+        JS_ASSERT(!counts);
     }
 
     bool init(JSContext *cx, size_t numBytecodes);
+    void destroy(JSContext *cx);
 
     // Boolean conversion, for 'if (counters) ...'
     operator void*() const {