diff --git a/src/glue.rs b/src/glue.rs
index e8ad875b0..d24767ef1 100644
--- a/src/glue.rs
+++ b/src/glue.rs
@@ -219,6 +219,7 @@ extern "C" {
     pub fn int_to_jsid(i: i32) -> jsid;
     pub fn RUST_JSID_IS_STRING(id: HandleId) -> bool;
     pub fn RUST_JSID_TO_STRING(id: HandleId) -> *mut JSString;
+    pub fn RUST_SYMBOL_TO_JSID(sym: *mut Symbol) -> jsid;
     pub fn RUST_SET_JITINFO(func: *mut JSFunction, info: *const JSJitInfo);
     pub fn RUST_INTERNED_STRING_TO_JSID(cx: *mut JSContext,
                                         str: *mut JSString) -> jsid;
diff --git a/src/jsglue.cpp b/src/jsglue.cpp
index b2b2ef41c..f69710344 100644
--- a/src/jsglue.cpp
+++ b/src/jsglue.cpp
@@ -593,6 +593,12 @@ RUST_JSID_TO_STRING(JS::HandleId id)
     return JSID_TO_STRING(id);
 }
 
+jsid
+RUST_SYMBOL_TO_JSID(JS::Symbol* sym)
+{
+    return SYMBOL_TO_JSID(sym);
+}
+
 void
 RUST_SET_JITINFO(JSFunction* func, const JSJitInfo* info) {
     SET_JITINFO(func, info);