diff --git a/include/binder/IInterface.h b/include/binder/IInterface.h
index 5f9f69c..4ce3613 100644
--- a/include/binder/IInterface.h
+++ b/include/binder/IInterface.h
@@ -28,9 +28,9 @@
 {
 public:
             IInterface();
-            sp<IBinder>         asBinder();
-            sp<const IBinder>   asBinder() const;
-            
+            static sp<IBinder>  asBinder(const IInterface*);
+            static sp<IBinder>  asBinder(const sp<IInterface>&);
+
 protected:
     virtual                     ~IInterface();
     virtual IBinder*            onAsBinder() = 0;
diff --git a/libs/binder/AppOpsManager.cpp b/libs/binder/AppOpsManager.cpp
index 61b4f7d..c562c30 100644
--- a/libs/binder/AppOpsManager.cpp
+++ b/libs/binder/AppOpsManager.cpp
@@ -44,7 +44,7 @@
     int64_t startTime = 0;
     mLock.lock();
     sp<IAppOpsService> service = mService;
-    while (service == NULL || !service->asBinder()->isBinderAlive()) {
+    while (service == NULL || !IInterface::asBinder(service)->isBinderAlive()) {
         sp<IBinder> binder = defaultServiceManager()->checkService(_appops);
         if (binder == NULL) {
             // Wait for the app ops service to come back...
diff --git a/libs/binder/IAppOpsService.cpp b/libs/binder/IAppOpsService.cpp
index f58a352..86abdc0 100644
--- a/libs/binder/IAppOpsService.cpp
+++ b/libs/binder/IAppOpsService.cpp
@@ -91,14 +91,14 @@
         data.writeInterfaceToken(IAppOpsService::getInterfaceDescriptor());
         data.writeInt32(op);
         data.writeString16(packageName);
-        data.writeStrongBinder(callback->asBinder());
+        data.writeStrongBinder(IInterface::asBinder(callback));
         remote()->transact(START_WATCHING_MODE_TRANSACTION, data, &reply);
     }
 
     virtual void stopWatchingMode(const sp<IAppOpsCallback>& callback) {
         Parcel data, reply;
         data.writeInterfaceToken(IAppOpsService::getInterfaceDescriptor());
-        data.writeStrongBinder(callback->asBinder());
+        data.writeStrongBinder(IInterface::asBinder(callback));
         remote()->transact(STOP_WATCHING_MODE_TRANSACTION, data, &reply);
     }
 
diff --git a/libs/binder/IInterface.cpp b/libs/binder/IInterface.cpp
index 99a9ffe..8c60dc4 100644
--- a/libs/binder/IInterface.cpp
+++ b/libs/binder/IInterface.cpp
@@ -27,14 +27,18 @@
 IInterface::~IInterface() {
 }
 
-sp<IBinder> IInterface::asBinder()
+// static
+sp<IBinder> IInterface::asBinder(const IInterface* iface)
 {
-    return onAsBinder();
+    if (iface == NULL) return NULL;
+    return const_cast<IInterface*>(iface)->onAsBinder();
 }
 
-sp<const IBinder> IInterface::asBinder() const
+// static
+sp<IBinder> IInterface::asBinder(const sp<IInterface>& iface)
 {
-    return const_cast<IInterface*>(this)->onAsBinder();
+    if (iface == NULL) return NULL;
+    return iface->onAsBinder();
 }
 
 // ---------------------------------------------------------------------------
diff --git a/libs/binder/IMemory.cpp b/libs/binder/IMemory.cpp
index d8ed995..e9891a8 100644
--- a/libs/binder/IMemory.cpp
+++ b/libs/binder/IMemory.cpp
@@ -216,7 +216,7 @@
             CHECK_INTERFACE(IMemory, data, reply);
             ssize_t offset;
             size_t size;
-            reply->writeStrongBinder( getMemory(&offset, &size)->asBinder() );
+            reply->writeStrongBinder( IInterface::asBinder(getMemory(&offset, &size)) );
             reply->writeInt32(offset);
             reply->writeInt32(size);
             return NO_ERROR;
@@ -241,7 +241,7 @@
         if (mRealHeap) {
             // by construction we're the last one
             if (mBase != MAP_FAILED) {
-                sp<IBinder> binder = const_cast<BpMemoryHeap*>(this)->asBinder();
+                sp<IBinder> binder = IInterface::asBinder(this);
 
                 if (VERBOSE) {
                     ALOGD("UNMAPPING binder=%p, heap=%p, size=%zu, fd=%d",
@@ -253,7 +253,7 @@
             }
         } else {
             // remove from list only if it was mapped before
-            sp<IBinder> binder = const_cast<BpMemoryHeap*>(this)->asBinder();
+            sp<IBinder> binder = IInterface::asBinder(this);
             free_heap(binder);
         }
     }
@@ -262,7 +262,7 @@
 void BpMemoryHeap::assertMapped() const
 {
     if (mHeapId == -1) {
-        sp<IBinder> binder(const_cast<BpMemoryHeap*>(this)->asBinder());
+        sp<IBinder> binder(IInterface::asBinder(const_cast<BpMemoryHeap*>(this)));
         sp<BpMemoryHeap> heap(static_cast<BpMemoryHeap*>(find_heap(binder).get()));
         heap->assertReallyMapped();
         if (heap->mBase != MAP_FAILED) {
@@ -297,7 +297,8 @@
         uint32_t offset = reply.readInt32();
 
         ALOGE_IF(err, "binder=%p transaction failed fd=%d, size=%zd, err=%d (%s)",
-                asBinder().get(), parcel_fd, size, err, strerror(-err));
+                IInterface::asBinder(this).get(),
+                parcel_fd, size, err, strerror(-err));
 
         int fd = dup( parcel_fd );
         ALOGE_IF(fd==-1, "cannot dup fd=%d, size=%zd, err=%d (%s)",
@@ -314,7 +315,7 @@
             mBase = mmap(0, size, access, MAP_SHARED, fd, offset);
             if (mBase == MAP_FAILED) {
                 ALOGE("cannot map BpMemoryHeap (binder=%p), size=%zd, fd=%d (%s)",
-                        asBinder().get(), size, fd, strerror(errno));
+                        IInterface::asBinder(this).get(), size, fd, strerror(errno));
                 close(fd);
             } else {
                 mSize = size;
diff --git a/libs/binder/IServiceManager.cpp b/libs/binder/IServiceManager.cpp
index 7b1b0e7..3c716df 100644
--- a/libs/binder/IServiceManager.cpp
+++ b/libs/binder/IServiceManager.cpp
@@ -87,7 +87,7 @@
             }
             
             // Is this a permission failure, or did the controller go away?
-            if (pc->asBinder()->isBinderAlive()) {
+            if (IInterface::asBinder(pc)->isBinderAlive()) {
                 ALOGW("Permission failure: %s from uid=%d pid=%d",
                         String8(permission).string(), uid, pid);
                 return false;
diff --git a/libs/gui/BufferQueueProducer.cpp b/libs/gui/BufferQueueProducer.cpp
index 16b9747..bf9c84d 100644
--- a/libs/gui/BufferQueueProducer.cpp
+++ b/libs/gui/BufferQueueProducer.cpp
@@ -807,8 +807,8 @@
             // Set up a death notification so that we can disconnect
             // automatically if the remote producer dies
             if (listener != NULL &&
-                    listener->asBinder()->remoteBinder() != NULL) {
-                status = listener->asBinder()->linkToDeath(
+                    IInterface::asBinder(listener)->remoteBinder() != NULL) {
+                status = IInterface::asBinder(listener)->linkToDeath(
                         static_cast<IBinder::DeathRecipient*>(this));
                 if (status != NO_ERROR) {
                     BQ_LOGE("connect(P): linkToDeath failed: %s (%d)",
@@ -857,7 +857,7 @@
                     // Remove our death notification callback if we have one
                     if (mCore->mConnectedProducerListener != NULL) {
                         sp<IBinder> token =
-                                mCore->mConnectedProducerListener->asBinder();
+                                IInterface::asBinder(mCore->mConnectedProducerListener);
                         // This can fail if we're here because of the death
                         // notification, but we just ignore it
                         token->unlinkToDeath(
diff --git a/libs/gui/IGraphicBufferConsumer.cpp b/libs/gui/IGraphicBufferConsumer.cpp
index f6d087d..cc581a3 100644
--- a/libs/gui/IGraphicBufferConsumer.cpp
+++ b/libs/gui/IGraphicBufferConsumer.cpp
@@ -273,7 +273,7 @@
     virtual status_t consumerConnect(const sp<IConsumerListener>& consumer, bool controlledByApp) {
         Parcel data, reply;
         data.writeInterfaceToken(IGraphicBufferConsumer::getInterfaceDescriptor());
-        data.writeStrongBinder(consumer->asBinder());
+        data.writeStrongBinder(IInterface::asBinder(consumer));
         data.writeInt32(controlledByApp);
         status_t result = remote()->transact(CONSUMER_CONNECT, data, &reply);
         if (result != NO_ERROR) {
diff --git a/libs/gui/IGraphicBufferProducer.cpp b/libs/gui/IGraphicBufferProducer.cpp
index 1e28f9b..bcdf368 100644
--- a/libs/gui/IGraphicBufferProducer.cpp
+++ b/libs/gui/IGraphicBufferProducer.cpp
@@ -211,7 +211,7 @@
         data.writeInterfaceToken(IGraphicBufferProducer::getInterfaceDescriptor());
         if (listener != NULL) {
             data.writeInt32(1);
-            data.writeStrongBinder(listener->asBinder());
+            data.writeStrongBinder(IInterface::asBinder(listener));
         } else {
             data.writeInt32(0);
         }
diff --git a/libs/gui/ISensorServer.cpp b/libs/gui/ISensorServer.cpp
index 0b76f37..a8464a2 100644
--- a/libs/gui/ISensorServer.cpp
+++ b/libs/gui/ISensorServer.cpp
@@ -91,7 +91,7 @@
         case CREATE_SENSOR_EVENT_CONNECTION: {
             CHECK_INTERFACE(ISensorServer, data, reply);
             sp<ISensorEventConnection> connection(createSensorEventConnection());
-            reply->writeStrongBinder(connection->asBinder());
+            reply->writeStrongBinder(IInterface::asBinder(connection));
             return NO_ERROR;
         } break;
     }
diff --git a/libs/gui/ISurfaceComposer.cpp b/libs/gui/ISurfaceComposer.cpp
index ebb687a..bc4baa3 100644
--- a/libs/gui/ISurfaceComposer.cpp
+++ b/libs/gui/ISurfaceComposer.cpp
@@ -113,7 +113,7 @@
         Parcel data, reply;
         data.writeInterfaceToken(ISurfaceComposer::getInterfaceDescriptor());
         data.writeStrongBinder(display);
-        data.writeStrongBinder(producer->asBinder());
+        data.writeStrongBinder(IInterface::asBinder(producer));
         data.write(sourceCrop);
         data.writeInt32(reqWidth);
         data.writeInt32(reqHeight);
@@ -137,7 +137,7 @@
                     "interface descriptor: %s (%d)", strerror(-err), -err);
             return false;
         }
-        err = data.writeStrongBinder(bufferProducer->asBinder());
+        err = data.writeStrongBinder(IInterface::asBinder(bufferProducer));
         if (err != NO_ERROR) {
             ALOGE("ISurfaceComposer::authenticateSurfaceTexture: error writing "
                     "strong binder to parcel: %s (%d)", strerror(-err), -err);
@@ -299,13 +299,13 @@
     switch(code) {
         case CREATE_CONNECTION: {
             CHECK_INTERFACE(ISurfaceComposer, data, reply);
-            sp<IBinder> b = createConnection()->asBinder();
+            sp<IBinder> b = IInterface::asBinder(createConnection());
             reply->writeStrongBinder(b);
             return NO_ERROR;
         }
         case CREATE_GRAPHIC_BUFFER_ALLOC: {
             CHECK_INTERFACE(ISurfaceComposer, data, reply);
-            sp<IBinder> b = createGraphicBufferAlloc()->asBinder();
+            sp<IBinder> b = IInterface::asBinder(createGraphicBufferAlloc());
             reply->writeStrongBinder(b);
             return NO_ERROR;
         }
@@ -378,7 +378,7 @@
         case CREATE_DISPLAY_EVENT_CONNECTION: {
             CHECK_INTERFACE(ISurfaceComposer, data, reply);
             sp<IDisplayEventConnection> connection(createDisplayEventConnection());
-            reply->writeStrongBinder(connection->asBinder());
+            reply->writeStrongBinder(IInterface::asBinder(connection));
             return NO_ERROR;
         }
         case CREATE_DISPLAY: {
diff --git a/libs/gui/ISurfaceComposerClient.cpp b/libs/gui/ISurfaceComposerClient.cpp
index f199e9f..de4d8c1 100644
--- a/libs/gui/ISurfaceComposerClient.cpp
+++ b/libs/gui/ISurfaceComposerClient.cpp
@@ -114,7 +114,7 @@
             status_t result = createSurface(name, w, h, format, flags,
                     &handle, &gbp);
             reply->writeStrongBinder(handle);
-            reply->writeStrongBinder(gbp != NULL ? gbp->asBinder() : NULL);
+            reply->writeStrongBinder(IInterface::asBinder(gbp));
             reply->writeInt32(result);
             return NO_ERROR;
         } break;
diff --git a/libs/gui/LayerState.cpp b/libs/gui/LayerState.cpp
index 39f8f92..ccf8b78 100644
--- a/libs/gui/LayerState.cpp
+++ b/libs/gui/LayerState.cpp
@@ -67,7 +67,7 @@
 }
 
 status_t ComposerState::write(Parcel& output) const {
-    output.writeStrongBinder(client->asBinder());
+    output.writeStrongBinder(IInterface::asBinder(client));
     return state.write(output);
 }
 
@@ -79,7 +79,7 @@
 
 status_t DisplayState::write(Parcel& output) const {
     output.writeStrongBinder(token);
-    output.writeStrongBinder(surface != NULL ? surface->asBinder() : NULL);
+    output.writeStrongBinder(IInterface::asBinder(surface));
     output.writeInt32(what);
     output.writeInt32(layerStack);
     output.writeInt32(orientation);
diff --git a/libs/gui/SensorManager.cpp b/libs/gui/SensorManager.cpp
index 7b4fa2f..17960ff 100644
--- a/libs/gui/SensorManager.cpp
+++ b/libs/gui/SensorManager.cpp
@@ -86,7 +86,7 @@
         };
 
         mDeathObserver = new DeathObserver(*const_cast<SensorManager *>(this));
-        mSensorServer->asBinder()->linkToDeath(mDeathObserver);
+        IInterface::asBinder(mSensorServer)->linkToDeath(mDeathObserver);
 
         mSensors = mSensorServer->getSensorList();
         size_t count = mSensors.size();
diff --git a/libs/gui/StreamSplitter.cpp b/libs/gui/StreamSplitter.cpp
index 5f39905..25e6cab 100644
--- a/libs/gui/StreamSplitter.cpp
+++ b/libs/gui/StreamSplitter.cpp
@@ -80,7 +80,7 @@
 
     IGraphicBufferProducer::QueueBufferOutput queueBufferOutput;
     sp<OutputListener> listener(new OutputListener(this, outputQueue));
-    outputQueue->asBinder()->linkToDeath(listener);
+    IInterface::asBinder(outputQueue)->linkToDeath(listener);
     status_t status = outputQueue->connect(listener, NATIVE_WINDOW_API_CPU,
             /* producerControlledByApp */ false, &queueBufferOutput);
     if (status != NO_ERROR) {
diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index 547dc7d..1be7895 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -71,7 +71,7 @@
     };
 
     mDeathObserver = new DeathObserver(*const_cast<ComposerService*>(this));
-    mComposerService->asBinder()->linkToDeath(mDeathObserver);
+    IInterface::asBinder(mComposerService)->linkToDeath(mDeathObserver);
 }
 
 /*static*/ sp<ISurfaceComposer> ComposerService::getComposerService() {
@@ -462,14 +462,14 @@
 }
 
 sp<IBinder> SurfaceComposerClient::connection() const {
-    return (mClient != 0) ? mClient->asBinder() : 0;
+    return IInterface::asBinder(mClient);
 }
 
 status_t SurfaceComposerClient::linkToComposerDeath(
         const sp<IBinder::DeathRecipient>& recipient,
         void* cookie, uint32_t flags) {
     sp<ISurfaceComposer> sm(ComposerService::getComposerService());
-    return sm->asBinder()->linkToDeath(recipient, cookie, flags);
+    return IInterface::asBinder(sm)->linkToDeath(recipient, cookie, flags);
 }
 
 void SurfaceComposerClient::dispose() {
diff --git a/libs/gui/SurfaceControl.cpp b/libs/gui/SurfaceControl.cpp
index 7597c99..61011b9 100644
--- a/libs/gui/SurfaceControl.cpp
+++ b/libs/gui/SurfaceControl.cpp
@@ -176,7 +176,7 @@
     if (control != NULL) {
         bp = control->mGraphicBufferProducer;
     }
-    return parcel->writeStrongBinder(bp->asBinder());
+    return parcel->writeStrongBinder(IInterface::asBinder(bp));
 }
 
 sp<Surface> SurfaceControl::getSurface() const
diff --git a/libs/gui/tests/BufferQueue_test.cpp b/libs/gui/tests/BufferQueue_test.cpp
index 96de11f..838ad90 100644
--- a/libs/gui/tests/BufferQueue_test.cpp
+++ b/libs/gui/tests/BufferQueue_test.cpp
@@ -87,8 +87,8 @@
         sp<IGraphicBufferConsumer> consumer;
         BufferQueue::createBufferQueue(&producer, &consumer);
         sp<IServiceManager> serviceManager = defaultServiceManager();
-        serviceManager->addService(PRODUCER_NAME, producer->asBinder());
-        serviceManager->addService(CONSUMER_NAME, consumer->asBinder());
+        serviceManager->addService(PRODUCER_NAME, IInterface::asBinder(producer));
+        serviceManager->addService(CONSUMER_NAME, IInterface::asBinder(consumer));
         ProcessState::self()->startThreadPool();
         IPCThreadState::self()->joinThreadPool();
         LOG_ALWAYS_FATAL("Shouldn't be here");
diff --git a/services/batteryservice/IBatteryPropertiesRegistrar.cpp b/services/batteryservice/IBatteryPropertiesRegistrar.cpp
index 296bfab..46934e0 100644
--- a/services/batteryservice/IBatteryPropertiesRegistrar.cpp
+++ b/services/batteryservice/IBatteryPropertiesRegistrar.cpp
@@ -34,14 +34,14 @@
         void registerListener(const sp<IBatteryPropertiesListener>& listener) {
             Parcel data;
             data.writeInterfaceToken(IBatteryPropertiesRegistrar::getInterfaceDescriptor());
-            data.writeStrongBinder(listener->asBinder());
+            data.writeStrongBinder(IInterface::asBinder(listener));
             remote()->transact(REGISTER_LISTENER, data, NULL);
         }
 
         void unregisterListener(const sp<IBatteryPropertiesListener>& listener) {
             Parcel data;
             data.writeInterfaceToken(IBatteryPropertiesRegistrar::getInterfaceDescriptor());
-            data.writeStrongBinder(listener->asBinder());
+            data.writeStrongBinder(IInterface::asBinder(listener));
             remote()->transact(UNREGISTER_LISTENER, data, NULL);
         }
 
diff --git a/services/surfaceflinger/MonitoredProducer.cpp b/services/surfaceflinger/MonitoredProducer.cpp
index 8739682..37a044e 100644
--- a/services/surfaceflinger/MonitoredProducer.cpp
+++ b/services/surfaceflinger/MonitoredProducer.cpp
@@ -49,7 +49,7 @@
         wp<IBinder> mProducer;
     };
 
-    mFlinger->postMessageAsync(new MessageCleanUpList(mFlinger, asBinder()));
+    mFlinger->postMessageAsync(new MessageCleanUpList(mFlinger, asBinder(this)));
 }
 
 status_t MonitoredProducer::requestBuffer(int slot, sp<GraphicBuffer>* buf) {
@@ -111,7 +111,7 @@
 }
 
 IBinder* MonitoredProducer::onAsBinder() {
-    return mProducer->asBinder().get();
+    return IInterface::asBinder(mProducer).get();
 }
 
 // ---------------------------------------------------------------------------
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 7d6d7c2..1060b09 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -496,7 +496,7 @@
 bool SurfaceFlinger::authenticateSurfaceTexture(
         const sp<IGraphicBufferProducer>& bufferProducer) const {
     Mutex::Autolock _l(mStateLock);
-    sp<IBinder> surfaceTextureBinder(bufferProducer->asBinder());
+    sp<IBinder> surfaceTextureBinder(IInterface::asBinder(bufferProducer));
     return mGraphicBufferProducerList.indexOf(surfaceTextureBinder) >= 0;
 }
 
@@ -1276,10 +1276,8 @@
                     // this display is in both lists. see if something changed.
                     const DisplayDeviceState& state(curr[j]);
                     const wp<IBinder>& display(curr.keyAt(j));
-                    const sp<IBinder> state_binder =
-                        state.surface != NULL ? state.surface->asBinder() : NULL;
-                    const sp<IBinder> draw_binder =
-                        draw[i].surface != NULL ? draw[i].surface->asBinder() : NULL;
+                    const sp<IBinder> state_binder = IInterface::asBinder(state.surface);
+                    const sp<IBinder> draw_binder = IInterface::asBinder(draw[i].surface);
                     if (state_binder != draw_binder) {
                         // changing the surface is like destroying and
                         // recreating the DisplayDevice, so we just remove it
@@ -1928,7 +1926,7 @@
     // add this layer to the current state list
     Mutex::Autolock _l(mStateLock);
     mCurrentState.layersSortedByZ.add(lbc);
-    mGraphicBufferProducerList.add(gbc->asBinder());
+    mGraphicBufferProducerList.add(IInterface::asBinder(gbc));
 }
 
 status_t SurfaceFlinger::removeLayer(const sp<Layer>& layer) {
@@ -2001,7 +1999,7 @@
         // NOTE: it would be better to use RTTI as we could directly check
         // that we have a Client*. however, RTTI is disabled in Android.
         if (s.client != NULL) {
-            sp<IBinder> binder = s.client->asBinder();
+            sp<IBinder> binder = IInterface::asBinder(s.client);
             if (binder != NULL) {
                 String16 desc(binder->getInterfaceDescriptor());
                 if (desc == ISurfaceComposerClient::descriptor) {
@@ -2048,7 +2046,7 @@
     if (disp.isValid()) {
         const uint32_t what = s.what;
         if (what & DisplayState::eSurfaceChanged) {
-            if (disp.surface->asBinder() != s.surface->asBinder()) {
+            if (IInterface::asBinder(disp.surface) != IInterface::asBinder(s.surface)) {
                 disp.surface = s.surface;
                 flags |= eDisplayTransactionNeeded;
             }
@@ -2939,7 +2937,7 @@
         // Prevent reads below from happening before the read from Message
         atomic_thread_fence(memory_order_acquire);
         if (what == MSG_API_CALL) {
-            result = impl->asBinder()->transact(code, data[0], reply);
+            result = IInterface::asBinder(impl)->transact(code, data[0], reply);
             barrier.open();
         } else if (what == MSG_EXIT) {
             exitRequested = true;
@@ -2989,7 +2987,7 @@
     // if we have secure windows on this display, never allow the screen capture
     // unless the producer interface is local (i.e.: we can take a screenshot for
     // ourselves).
-    if (!producer->asBinder()->localBinder()) {
+    if (!IInterface::asBinder(producer)->localBinder()) {
         Mutex::Autolock _l(mStateLock);
         sp<const DisplayDevice> hw(getDisplayDevice(display));
         if (hw->getSecureLayerVisible()) {
@@ -3053,7 +3051,7 @@
             result = flinger->captureScreenImplLocked(hw, producer,
                     sourceCrop, reqWidth, reqHeight, minLayerZ, maxLayerZ,
                     useIdentityTransform, rotation);
-            static_cast<GraphicProducerWrapper*>(producer->asBinder().get())->exit(result);
+            static_cast<GraphicProducerWrapper*>(IInterface::asBinder(producer).get())->exit(result);
             return true;
         }
     };