--- a/js/src/asmjs/WasmCode.h
+++ b/js/src/asmjs/WasmCode.h
@@ -165,17 +165,20 @@ class FuncImport
     Sig sig_;
     struct CacheablePod {
         uint32_t exitGlobalDataOffset_;
         uint32_t interpExitCodeOffset_;
         uint32_t jitExitCodeOffset_;
     } pod;
 
   public:
-    FuncImport() = default;
+    FuncImport() {
+      memset(&pod, 0, sizeof(CacheablePod));
+    }
+
     FuncImport(Sig&& sig, uint32_t exitGlobalDataOffset)
       : sig_(Move(sig))
     {
         pod.exitGlobalDataOffset_ = exitGlobalDataOffset;
         pod.interpExitCodeOffset_ = 0;
         pod.jitExitCodeOffset_ = 0;
     }