Bug 601968. Trace call(null). r=gal, a=sayrer

js/src/jstracer.cpp

@@ -13435,9 +13435,9 @@ TraceRecorder::record_JSOP_APPLY()
 
     /*
      * We don't trace apply and call with a primitive 'this', which is the
-     * first positional parameter.
+     * first positional parameter, unless 'this' is null.  That's ok.
      */
-    if (argc > 0 && !vp[2].isObject())
+    if (argc > 0 && !vp[2].isObjectOrNull())
         return record_JSOP_CALL();
 
     /*

js/src/trace-test/tests/basic/testCallNull.js

@@ -0,0 +1,9 @@
+function f() {}
+for (var i = 0; i < HOTLOOP; ++i) {
+    f.call(null);
+}
+
+checkStats({
+    recorderStarted: 1,
+    recorderAborted: 0
+});