CppCon 2017

“A 14 year old code base under active development, 2.5 million lines of C++ code, a few brave nerds, two powerful tools and one hot summer…”, or “How we managed to clang-tidy our whole code base, while maintaining our monthly release cycle”. Did I mention that we’re a Windows-only dev team using Visual C++ ? That’s right, we’re going to continue using both Visual Studio (2017) and Clang tools on the side, to modernize and improve our code quality.

I’ve just come back from an interesting journey … and I want to share with you some of the most exciting experiences my team and I had along the way and a few things we’ve learned that you may take with you on your next “travels”. It all started a year ago, at CppCon, with a simple but life changing decision: we would stop worrying about whitespace and started our addiction on smart C++ tools with clang-format. We didn’t realize this at that time, but this was just the first leg of our great journey; next we decided to hop on the clang-tidy train and set out to modernize our aging code base and find hidden bugs along the way with clang-tidy static analyzer.

The hard part was getting all our code to compile with clang, using the correct project settings (synced with Visual Studio) and Windows SDK dependencies (our code has a fairly wide Windows API surface area). After that, clang-tidy was a breeze to use and we immediately integrated it in our workflow. I still cannot believe the code transformations we were able to do with its ‘modernize’ modules and some of the subtle latent bugs we found and fixed with its static analyzer and ‘cppcoreguidelines’.
Luckily, we took a lot of pictures and kept a detailed travel log, to share this fruitful journey with you, now. We’ll also share some tools we developed, to help you with this workflow: automation tips & configs (Jenkins, MSBuild), open-source PowerShell scripts (clang-tidy on Visual Studio projects), free Visual Studio extension and more.