Bug 818958: Tell SPSProfiler when the JS runtime shuts down r=luke

js/xpconnect/src/XPCJSRuntime.cpp

@@ -1308,6 +1308,11 @@ XPCJSRuntime::~XPCJSRuntime()
         fprintf(stderr, "nJRSI: destroyed runtime %p\n", (void *)mJSRuntime);
 #endif
     }
+#ifdef MOZ_ENABLE_PROFILER_SPS
+    // Tell the profiler that the runtime is gone
+    if (ProfileStack *stack = mozilla_profile_stack())
+        stack->sampleRuntime(nullptr);
+#endif
 
 #ifdef DEBUG
     for (uint32_t i = 0; i < XPCCCX_STRING_CACHE_SIZE; ++i) {

tools/profiler/sps_sampler.h

@@ -368,6 +368,11 @@ public:
 
   void sampleRuntime(JSRuntime *runtime) {
     mRuntime = runtime;
+    if (!runtime) {
+      // JS shut down
+      return;
+    }
+
     JS_STATIC_ASSERT(sizeof(mStack[0]) == sizeof(js::ProfileEntry));
     js::SetRuntimeProfilingStack(runtime,
                                  (js::ProfileEntry*) mStack,