关于CTS编译的问题

Question

Install: out/target/product/maguro/data/app/CtsUsePermissionDiffCert.odex
Install: out/target/product/maguro/data/app/CtsUsePermissionDiffCert.apk
Proguard: out/target/common/obj/APPS/CtsMonkeyApp_intermediates/proguard.classes.jar
ProGuard, version 4.4
Reading program jar [/root/Android/out/target/common/obj/APPS/CtsMonkeyApp_intermediates/classes.jar]
Reading library jar [/root/Android/out/target/common/obj/JAVA_LIBRARIES/android_stubs_current_intermediates/classes.jar]
Error: The output jar is empty. Did you specify the proper '-keep' options?
make: *** [out/target/common/obj/APPS/CtsMonkeyApp_intermediates/proguard.classes.jar] Error 1
root@ubuntu:~/Android# 
我之前执行了lunch full_maguro-user，然后执行make cts 提示上面的错误。有没有高手解释下啊！~