Update: v1.2.0 confirms that
eosiocpp has been deprecated:
eosiocpp this multi-tool has been deprecated in this release and
will be removed in
v1.3.0. It has been supplanted by on-going effort
Also documentation on writing an ABI.
As of v1.2.0, the eosio.wasmsdk was decoupled from the core
repository. This change has introduced an eosiocpp regression where
the legacy eosio-abigen is no longer bundled with eosio-cpp. Until a
new ABI generator is introduced, you will need to hand-write your ABI
From Telegram (11th August, 2018):
Todd Fleming: A quick summary on toolset status: eosiocpp (no hyphen)
is deprecated and no longer installed by default. It was a script.
eosio-cpp replaces it; it’s an executable, not a script, and is part
of wasmsdk. eosiocpp automatically invoked the old abi generator,
which is also deprecated. There are too many cases the old generator
couldn’t handle. The new abi generator is under development; it’s not
ready. For now, we recommend writing ABIs by hand.
Todd Fleming: It generated a file with an .abi extension. You now have
to write that file yourself. It has a simple syntax, but no
documentation yet. Documentation is currently being written. Look
through the new contracts repo for .abi files to see examples.
So, to answer your question, neither tools are recommended to use anymore.