LLVMClang

LLVM Clang, commonly referred to simply as Clang, is the C, C++, Objective-C, and Objective-C++ frontend for the LLVM compiler infrastructure. It translates source code into LLVM intermediate representation (IR), which the LLVM back end then optimizes and targets to machine code. Clang is designed to be fast, modular, and with expressive diagnostics, and it integrates tightly with the rest of the LLVM project to provide a unified toolchain for compiling, analyzing, and transforming code.

Core features include a modern, permissively licensed codebase, libclang for C interfaces, and tooling such as Clang-Tidy, Clang-Format, and LibTooling that enable static analysis, automated refactoring, and custom tooling. Clang strives for GCC compatibility in error messages and command-line options, while offering more precise diagnostics and a clearer frontend. It supports various language standards (C, C++, Objective-C, and Objective-C++), with ongoing support for newer standards, as well as targets for many architectures (x86-64, ARM, AArch64, and others). It also interoperates with LLVM's optimizers, code generators, and link-time optimization (LTO).

Clang is part of the LLVM project, an open-source, community-driven effort, and is distributed under the University of Illinois/NCSA Open Source License. It is widely used in major platforms and toolchains, including Apple's Xcode, many Linux distributions, and the Android NDK. The project emphasizes clean design, modularity, and tool-building support, making Clang a preferred frontend for both production compilers and development tooling.