RFC: JEP JDK-8208089: Implement C++14 Language Features

[Erik Helin]

On 10/4/18 2:31 PM, Magnus Ihse Bursie wrote:>> 4 okt. 2018 kl. 10:57 
skrev Martijn Verburg <martijnverburg at gmail.com>:
>> I like this initiative.  I'm wondering if some of these rules can be easily
>> codified or written into a jcheck style checker (ccheck?) so that Authors
>> can adhere to the conventions and not rely on a Human review to pick out
>> where that convention isn't met.
> 
> That's an interesting thought!
> 
> I googled around a bit, but could find no obvious candidate for doing such a check. In fact, parsing and analyzing C++ seems quite a hard problem, compared to many other languages. (Sad, but not really surprising.)
> 
> I found two possible routes to explore: cpplint [1], the official Google tool to verify that the Google C++ Style Guide [2] is followed, and Vera++ [3], a framework for creating scripts that can analyze and/or transform C++ code.

As usual there is of a third route, this one is "just a matter of 
programming" :)

The (probably) easiest way to enforce usage of only a subset of C++ is 
to write custom clang-tidy checks [0]. We could most likely write a 
couple of ASTMatchers [1] to watch out for features we do not want. It 
used to be very hard to use the clang tooling with HotSpot, but thanks 
to Robin Westberg's compile-commands patch [2] that just went in, this 
is no longer an issue.

Unfortunately I don't think requiring all contributors to install a 
custom version of clang-tidy with HotSpot checks is feasible, this is 
more something you would want to run in a CI setup.

Thanks,
Erik

[0]: https://clang.llvm.org/extra/clang-tidy/#writing-a-clang-tidy-check
[1]: http://clang.llvm.org/docs/LibASTMatchers.html
[2]: http://hg.openjdk.java.net/jdk/jdk/rev/804792ce736f