[cfe-dev] converting a LibTooling tool to a library

[Eric Schulte]

Manuel Klimek <klimek at google.com> writes:

> On Fri, Oct 26, 2012 at 5:48 PM, Eric Schulte <schulte.eric at gmail.com>wrote:
>
>> Hi,
>>
>> I've written a simple command-line code-mutation tool using the Tooling
>> infrastructure [1].  The tooling framework handled many of the difficult
>> portions of this task (handling compilation databases etc...) allowing
>> me to focus on writing a RecursiveASTVisitor -- my thanks to everyone
>> who worked on the tooling setup and on clang in general.
>>
>
> :)
>
> I would now like to expose the functionality of this ASTVisitor as a C
>> library so that I can call these functions programatically and chain
>> multiple ASTConsumers without the overhead of multiple shell calls,
>> repeatedly parsing of the original source, etc...
>>
>> Is this possible?  Is this difficult?  Is there a best practice for
>> transitioning from a command-line Tooling tool to a library?  Should I
>> just look though the clang/Tooling source?  Any pointers or suggestions
>> would be greatly appreciated.
>>
>
> I think you're the first one to go this route - one thing I notice is that
> you say "C library". I assume that's a requirement? In general, the way I'd
> go about this is:
> - build a C++ library
> - build a C wrapper that exposes the functionality
>

Great, I'll take this approach.  Hopefully it won't be overly difficult
to pull the relevant preparatory code (source -> AST conversion) out of
the existing Tooling libraries.

>
> That's pretty much the way libclang does it (minus some stuff that's only
> in libclang, but we've already noticed some of that stuff would be very
> nice to have in a C++ layer).
>
> Your tool is also sufficiently narrow focus currently that I think it might
> make sense to go into clang mainline as a library and be useful from
> libclang, but Doug might have a different opinion.
>

I initially hoped to use libclang for this work but found it did not
include any Code Rewriting functionality.  I don't know if my ASTMutate
library is the best abstraction around code rewriting, but I would love
to see some rewriting support in libclang.

>
>
>> Thanks,
>>
>> Footnotes:
>> [1]  https://github.com/eschulte/clang-mutate
>
>
> Nice! Looks awesome :)
> /me wonders whether it would be a perfect fit for the extra-tools
> repository...
>

This does seem like it could be a nice fit.  If the extra-tools repo
would like to include this mutation tool then I'm happy to help with the
integration, just let me know what I can do.

Thanks,

>
> Cheers,
> /Manuel

-- 
Eric Schulte
http://cs.unm.edu/~eschulte