LLVM

LLVM (formerly Low Level Virtual Machine) is compiler infrastructure written in C++; it is designed for compile-time, link-time, run-time, and "idle-time" optimization of programs written in arbitrary programming languages. Originally implemented for C and C++, the language-agnostic design (and the success) of LLVM has since spawned a wide variety of front ends: languages with compilers which use LLVM include Objective-C, Fortran, Ada, Haskell, Java bytecode, Python, Ruby, ActionScript, GLSL, D, and Rust.

The LLVM project started in 2000 at the University of Illinois at Urbana–Champaign, under the direction of Vikram Adve and Chris Lattner. LLVM was originally developed as a research infrastructure to investigate dynamic compilation techniques for static and dynamic programming languages. LLVM was released under the University of Illinois Open Source License, a BSD-style license. In 2005, Apple Inc. hired Lattner and formed a team to work on the LLVM system for various uses within Apple's development systems. LLVM is an integral part of Apple's latest development tools for Mac OS X and iOS.

The name LLVM was originally an initialism for Low Level Virtual Machine, but the initialism caused widespread confusion because the scope of the project is not limited to the creation of virtual machines. As the scope of LLVM grew even further, it became an umbrella project that includes a variety of other compiler and low-level tool technologies as well, making the name even less apt. As such, the project abandoned the initialism. Now, LLVM is a brand that applies to the LLVM umbrella project, the LLVM intermediate representation, the LLVM debugger, the LLVM C++ standard library, etc.