diff --git a/transport/HidlBinderSupport.cpp b/transport/HidlBinderSupport.cpp
index f6c7bff..015d607 100644
--- a/transport/HidlBinderSupport.cpp
+++ b/transport/HidlBinderSupport.cpp
@@ -18,6 +18,8 @@
 
 #include <hidl/HidlBinderSupport.h>
 
+#include <InternalStatic.h>  // TODO(b/69122224): remove this include, for getOrCreateCachedBinder
+
 // C includes
 #include <unistd.h>
 
@@ -196,6 +198,42 @@
     return status;
 }
 
+sp<IBinder> getOrCreateCachedBinder(::android::hidl::base::V1_0::IBase* ifacePtr) {
+    LOG_ALWAYS_FATAL_IF(ifacePtr->isRemote(),
+                        "getOrCreateCachedBinder does not have a way to construct remote binders");
+
+    std::string descriptor = details::getDescriptor(ifacePtr);
+    if (descriptor.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(descriptor, nullptr);
+        if (!func) {
+            // TODO(b/69122224): remove this static variable when prebuilts updated
+            func = details::gBnConstructorMap.get(descriptor, 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;
+}
+
 static bool gThreadPoolConfigured = false;
 
 void configureBinderRpcThreadpool(size_t maxThreads, bool callerWillJoin) {
diff --git a/transport/HidlPassthroughSupport.cpp b/transport/HidlPassthroughSupport.cpp
index e5eb164..ff68a1e 100644
--- a/transport/HidlPassthroughSupport.cpp
+++ b/transport/HidlPassthroughSupport.cpp
@@ -16,6 +16,8 @@
 
 #include <hidl/HidlPassthroughSupport.h>
 
+#include <InternalStatic.h>  // TODO(b/69122224): remove this include, for tryWrap
+
 #include <hidl/HidlTransportUtils.h>
 #include <hidl/Static.h>
 
@@ -28,6 +30,7 @@
 static sp<IBase> tryWrap(const std::string& descriptor, sp<IBase> iface) {
     auto func = getBsConstructorMap().get(descriptor, nullptr);
     if (!func) {
+        // TODO(b/69122224): remove this when prebuilts don't reference it
         func = gBsConstructorMap.get(descriptor, nullptr);
     }
     if (func) {
diff --git a/transport/InternalStatic.h b/transport/InternalStatic.h
new file mode 100644
index 0000000..b0fefa9
--- /dev/null
+++ b/transport/InternalStatic.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// This file is for legacy static variables that we are trying to get rid of.
+// TODO(b/69122224): remove this file
+
+#ifndef ANDROID_HARDWARE_HIDL_INTERNAL_STATIC_H
+#define ANDROID_HARDWARE_HIDL_INTERNAL_STATIC_H
+
+#include <hidl/Static.h>
+
+namespace android {
+namespace hardware {
+namespace details {
+
+// deprecated; use getBnConstructorMap instead.
+extern BnConstructorMap gBnConstructorMap;
+// deprecated; use getBsConstructorMap instead.
+extern BsConstructorMap gBsConstructorMap;
+
+}  // namespace details
+}  // namespace hardware
+}  // namespace android
+
+#endif
diff --git a/transport/Static.cpp b/transport/Static.cpp
index 9875311..45ae27c 100644
--- a/transport/Static.cpp
+++ b/transport/Static.cpp
@@ -17,6 +17,7 @@
 // All static variables go here, to control initialization and
 // destruction order in the library.
 
+#include <InternalStatic.h>
 #include <hidl/Static.h>
 
 #include <android/hidl/manager/1.0/IServiceManager.h>
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