Chris Lattner: LLVM, Clang, and the Creation of Swift

Chris Lattner (born 1978) is one of the primary initiators and authors of the LLVM project and the author of the Clang compiler. He now heads Apple’s Developer Tools division, leading the Xcode, Instruments, and compiler teams, and has been leading the development of the Swift programming language since July 2010. Below is his introduction of himself and Swift.

I am the original author and chief architect of the LLVM compiler, an ambitious project whose goal is to build a reusable compiler component system that can be used to construct various tools, including compilers, debuggers, JIT systems, optimizers, static analysis systems, and more. LLVM is commonly used as an optimizer for C and C++, capable of generating machine code for many different architectures. The Clang project (also initiated by me) is now the industry‑leading C, Objective‑C, and C++ compiler, widely used in both academia and industry. In language support and other features, the LLDB debugger pioneered many advances. LLVM is being expanded in many directions to support new optimizations, new targets, new domains, and new features. For my work on LLVM I have received two ACM awards.

Translation note: Apple is the main sponsor of the LLVM project. In its early years Apple used GCC as its official compiler, but was dissatisfied with GCC’s performance, the low priority given to Objective‑C, and GCC’s limited support for new Objective‑C language features. Consequently Apple sought an open‑source compiler alternative and turned to LLVM. In 2005 Apple directly hired Chris Lattner and his team to develop application systems for Apple computers. (Excerpt from Wikipedia)

After joining Apple in 2005 I held several different positions, including engineer, first‑line manager, and second‑line manager. Over the years I have promoted LLVM technology throughout the Apple ecosystem, replacing GCC as the system compiler, making LLDB more realistic, and collaborating with the internal hardware team. I am currently the head of the Developer Tools division, leading the Xcode, Instruments, and compiler teams.

I began work on the Swift programming language in July 2010. I built most of the language’s core infrastructure, and only a few people knew about the project at first. By the end of 2011 several outstanding colleagues joined, and in July 2013 the Swift project became the main focus of Apple’s Developer Tools department.

Swift is the product of the team’s relentless effort, with members including language experts, documentation specialists, compiler‑optimization gurus, and an internal “dogfooding” team that provides feedback and testing ideas. Swift also benefits from experience with many languages, including Objective‑C, Rust, Haskell, Ruby, Python, C#, CLU, and others.

Translation note: “Dogfooding” is short for “Eating your own dog food”, a slang term used to describe a company (especially a software company) using its own product. The phrase may have originated around 1988 when Microsoft senior executive Paul Maritz wrote an email titled “Eating our own Dogfood”, challenging the internal testing lead to increase internal use of Microsoft’s own tools. The slang spread throughout the industry thereafter. (Excerpt from Wikipedia)

Xcode Playgrounds and the REPL are my personal passion, aiming to make programming more interactive and approachable. The Xcode and LLDB teams have turned crazy ideas into real products. Playgrounds is heavily influenced by Bret Victor’s ideas, Light Table, and many other interactive systems. I hope to make programming more accessible and fun, and we will call on the next generation of programmers to help redefine computer‑science education.