--- a/js/jsd/jsd_xpc.cpp
+++ b/js/jsd/jsd_xpc.cpp
@@ -55,16 +55,19 @@
 #include "jsdebug.h"
 #include "nsReadableUtils.h"
 #include "nsCRT.h"
 
 /* XXX DOM dependency */
 #include "nsIScriptContext.h"
 #include "nsIJSContextStack.h"
 
+/* XXX private JS headers. */
+#include "jscompartment.h"
+
 /*
  * defining CAUTIOUS_SCRIPTHOOK makes jsds disable GC while calling out to the
  * script hook.  This was a hack to avoid some js engine problems that should
  * be fixed now (see Mozilla bug 77636).
  */
 #undef CAUTIOUS_SCRIPTHOOK
 
 #ifdef DEBUG_verbose
@@ -1314,20 +1317,24 @@ jsdScript::GetFunctionSource(nsAString &
         NS_WARNING("No default context !?");
         return NS_ERROR_FAILURE;
     }
     JSFunction *fun = JSD_GetJSFunction (mCx, mScript);
 
     JSAutoRequest ar(cx);
 
     JSString *jsstr;
-    if (fun)
+    if (fun) {
+        JSAutoEnterCompartment ac;
+        if (!ac.enter(cx, JS_GetFunctionObject(fun)))
+            return NS_ERROR_FAILURE;
         jsstr = JS_DecompileFunction (cx, fun, 4);
-    else {
+    } else {
         JSScript *script = JSD_GetJSScript (mCx, mScript);
+        js::SwitchToCompartment sc(cx, script->compartment);
         jsstr = JS_DecompileScript (cx, script, "ppscript", 4);
     }
     if (!jsstr)
         return NS_ERROR_FAILURE;
 
     aFunctionSource =
         nsDependentString(
             reinterpret_cast<PRUnichar*>(JS_GetStringChars(jsstr)),

--- a/js/src/jsapi.cpp
+++ b/js/src/jsapi.cpp
@@ -4721,17 +4721,20 @@ JS_CompileFunction(JSContext *cx, JSObje
 JS_PUBLIC_API(JSString *)
 JS_DecompileScript(JSContext *cx, JSScript *script, const char *name, uintN indent)
 {
     JS_THREADSAFE_ASSERT(cx->compartment != cx->runtime->defaultCompartment);
     JSPrinter *jp;
     JSString *str;
 
     CHECK_REQUEST(cx);
-    assertSameCompartment(cx, script);
+#ifdef DEBUG
+    if (cx->compartment != script->compartment)
+        CompartmentChecker::fail(cx->compartment, script->compartment);
+#endif
     jp = js_NewPrinter(cx, name, NULL,
                        indent & ~JS_DONT_PRETTY_PRINT,
                        !(indent & JS_DONT_PRETTY_PRINT),
                        false, false);
     if (!jp)
         return NULL;
     if (js_DecompileScript(jp, script))
         str = js_GetPrinterOutput(jp);