#0 0x0000000000c2bcc0 in HPHP::getSerializeProps (obj=obj@entry=0x7f523b1f7940, serializer=serializer@entry=0x7f5235bf9080) at /tmp/buildd/hhvm-3.12.1+dfsg/hphp/runtime/base/variable-serializer.cpp:1508
1508 in /tmp/buildd/hhvm-3.12.1+dfsg/hphp/runtime/base/variable-serializer.cpp