diff --git a/transport/include/hidl/HidlBinderSupport.h b/transport/include/hidl/HidlBinderSupport.h
index 1545946..6d45f39 100644
--- a/transport/include/hidl/HidlBinderSupport.h
+++ b/transport/include/hidl/HidlBinderSupport.h
@@ -301,6 +301,10 @@
 
 // ---------------------- support for casting interfaces
 
+// Constructs a binder for this interface and caches it. If it has already been created
+// then it returns it. ifacePtr must be a local object.
+sp<IBinder> getOrCreateCachedBinder(::android::hidl::base::V1_0::IBase* ifacePtr);
+
 // Construct a smallest possible binder from the given interface.
 // If it is remote, then its remote() will be retrieved.
 // Otherwise, the smallest possible BnChild is found where IChild is a subclass of IType
@@ -317,35 +321,7 @@
         return ::android::hardware::IInterface::asBinder(
             static_cast<BpInterface<IType>*>(ifacePtr));
     } else {
-        std::string myDescriptor = details::getDescriptor(ifacePtr);
-        if (myDescriptor.empty()) {
-            // interfaceDescriptor fails
-            return nullptr;
-        }
-
-        // for get + set
-        std::unique_lock<std::mutex> _lock = details::gBnMap.lock();
-
-        wp<BHwBinder> wBnObj = details::gBnMap.getLocked(ifacePtr, nullptr);
-        sp<IBinder> sBnObj = wBnObj.promote();
-
-        if (sBnObj == nullptr) {
-            auto func = details::getBnConstructorMap().get(myDescriptor, nullptr);
-            if (!func) {
-                func = details::gBnConstructorMap.get(myDescriptor, nullptr);
-                if (!func) {
-                    return nullptr;
-                }
-            }
-
-            sBnObj = sp<IBinder>(func(static_cast<void*>(ifacePtr)));
-
-            if (sBnObj != nullptr) {
-                details::gBnMap.setLocked(ifacePtr, static_cast<BHwBinder*>(sBnObj.get()));
-            }
-        }
-
-        return sBnObj;
+        return getOrCreateCachedBinder(ifacePtr);
     }
 }
 
diff --git a/transport/include/hidl/Static.h b/transport/include/hidl/Static.h
index 6ff6a9f..b50c173 100644
--- a/transport/include/hidl/Static.h
+++ b/transport/include/hidl/Static.h
@@ -47,8 +47,6 @@
 // For HidlBinderSupport and autogenerated code
 // value function receives reinterpret_cast<void *>(static_cast<IFoo *>(foo)),
 // returns sp<IBinder>
-// deprecated; use getBnConstructorMap instead.
-extern BnConstructorMap gBnConstructorMap;
 BnConstructorMap& getBnConstructorMap();
 
 using BsConstructorMap = ConcurrentMap<std::string,
@@ -56,8 +54,6 @@
 // For HidlPassthroughSupport and autogenerated code
 // value function receives reinterpret_cast<void *>(static_cast<IFoo *>(foo)),
 // returns sp<IBase>
-// deprecated; use getBsConstructorMap instead.
-extern BsConstructorMap gBsConstructorMap;
 BsConstructorMap& getBsConstructorMap();
 }  // namespace details
 }  // namespace hardware