Improve codegen failure handling

[zhouyuan]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
currently the codegen failures are not handled properly, sometimes it will break thrift-server.

Describe the solution you'd like
Need to handle those failures/segfaults, gracefully send to thrift-server

Describe alternatives you've considered
N/A

Additional context
N/A