diff --git a/js/src/jsapi.cpp b/js/src/jsapi.cpp
index 0b2a4ce3520..f9b697729d0 100644
--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -6587,6 +6587,12 @@ JS_ThrowStopIteration(JSContext *cx)
     return js_ThrowStopIteration(cx);
 }
 
+JS_PUBLIC_API(intptr_t)
+JS_GetCurrentThread()
+{
+    return reinterpret_cast<intptr_t>(js_CurrentThreadId());
+}
+
 /*
  * Get the owning thread id of a context. Returns 0 if the context is not
  * owned by any thread.
@@ -6595,7 +6601,7 @@ JS_PUBLIC_API(intptr_t)
 JS_GetContextThread(JSContext *cx)
 {
 #ifdef JS_THREADSAFE
-    return reinterpret_cast<intptr_t>(JS_THREAD_ID(cx));
+    return cx->thread() ? reinterpret_cast<intptr_t>(cx->thread()->id) : 0;
 #else
     return 0;
 #endif
diff --git a/js/src/jsapi.h b/js/src/jsapi.h
index a982ae6f8ef..f6afedf41ef 100644
--- a/js/src/jsapi.h
+++ b/js/src/jsapi.h
@@ -4929,6 +4929,9 @@ JS_ThrowReportedError(JSContext *cx, const char *message,
 extern JS_PUBLIC_API(JSBool)
 JS_ThrowStopIteration(JSContext *cx);
 
+extern JS_PUBLIC_API(intptr_t)
+JS_GetCurrentThread();
+
 /*
  * Associate the current thread with the given context.  This is done
  * implicitly by JS_NewContext.
diff --git a/js/src/jscntxt.h b/js/src/jscntxt.h
index ac7ae79a454..774da801c9c 100644
--- a/js/src/jscntxt.h
+++ b/js/src/jscntxt.h
@@ -1310,10 +1310,6 @@ struct JSContext
 
 namespace js {
 
-#ifdef JS_THREADSAFE
-# define JS_THREAD_ID(cx)       ((cx)->thread() ? (cx)->thread()->id : 0)
-#endif
-
 #if defined JS_THREADSAFE && defined DEBUG
 
 class AutoCheckRequestDepth {
diff --git a/js/src/jsfriendapi.cpp b/js/src/jsfriendapi.cpp
index d643ee71deb..a6e4fa81290 100644
--- a/js/src/jsfriendapi.cpp
+++ b/js/src/jsfriendapi.cpp
@@ -458,3 +458,15 @@ js::DumpHeapComplete(JSContext *cx, FILE *fp)
 }
 
 #endif
+
+namespace js {
+
+#ifdef JS_THREADSAFE
+JSThread *
+GetContextThread(const JSContext *cx)
+{
+    return cx->thread();
+}
+#endif
+
+} // namespace js
diff --git a/js/src/jsfriendapi.h b/js/src/jsfriendapi.h
index 3b6c06fa3ca..292a4988c62 100644
--- a/js/src/jsfriendapi.h
+++ b/js/src/jsfriendapi.h
@@ -445,6 +445,11 @@ GetPCCountScriptSummary(JSContext *cx, size_t script);
 JS_FRIEND_API(JSString *)
 GetPCCountScriptContents(JSContext *cx, size_t script);
 
+#ifdef JS_THREADSAFE
+JS_FRIEND_API(JSThread *)
+GetContextThread(const JSContext *cx);
+#endif
+
 } /* namespace js */
 
 /*
diff --git a/js/xpconnect/src/XPCThreadContext.cpp b/js/xpconnect/src/XPCThreadContext.cpp
index c85539817d6..c96385616f1 100644
--- a/js/xpconnect/src/XPCThreadContext.cpp
+++ b/js/xpconnect/src/XPCThreadContext.cpp
@@ -423,7 +423,7 @@ XPCPerThreadData::GetDataImpl(JSContext *cx)
     }
 
     if (cx && !sMainJSThread && NS_IsMainThread()) {
-        sMainJSThread = cx->thread();
+        sMainJSThread = js::GetContextThread(cx);
 
         sMainThreadData = data;
 
diff --git a/js/xpconnect/src/XPCWrappedJSClass.cpp b/js/xpconnect/src/XPCWrappedJSClass.cpp
index 10725a1e0a1..973ff5d7fce 100644
--- a/js/xpconnect/src/XPCWrappedJSClass.cpp
+++ b/js/xpconnect/src/XPCWrappedJSClass.cpp
@@ -552,7 +552,7 @@ GetContextFromObject(JSObject *obj)
 
     if (xpcc) {
         JSContext *cx = xpcc->GetJSContext();
-        if (cx->thread()->id == js_CurrentThreadId())
+        if (JS_GetContextThread(cx) == JS_GetCurrentThread())
             return cx;
     }
 
diff --git a/js/xpconnect/src/xpcprivate.h b/js/xpconnect/src/xpcprivate.h
index 2542fec62fc..4fec388fdf1 100644
--- a/js/xpconnect/src/xpcprivate.h
+++ b/js/xpconnect/src/xpcprivate.h
@@ -3646,9 +3646,9 @@ public:
     static inline XPCPerThreadData* GetData(JSContext *cx)
     {
         if (cx) {
-            NS_ASSERTION(cx->thread(), "Uh, JS context w/o a thread?");
+            NS_ASSERTION(js::GetContextThread(cx), "Uh, JS context w/o a thread?");
 
-            if (cx->thread() == sMainJSThread)
+            if (js::GetContextThread(cx) == sMainJSThread)
                 return sMainThreadData;
         } else if (sMainThreadData && sMainThreadData->mThread == PR_GetCurrentThread()) {
             return sMainThreadData;
@@ -3751,7 +3751,7 @@ public:
         {sMainJSThread = nsnull; sMainThreadData = nsnull;}
 
     static bool IsMainThread(JSContext *cx)
-        { return cx->thread() == sMainJSThread; }
+        { return js::GetContextThread(cx) == sMainJSThread; }
 
 private:
     XPCPerThreadData();