clang: a C language family frontend for LLVM

About

- -

The goal of the Clang project is to create a new BSD - licensed C, C++, & ObjC front-end for the LLVM compiler.

- -

In the context of this website, the term Clang actually refers to two - things:

- -

A "code name" for the LLVM compiler front-end.
A specific library in the LLVM front-end -- in particular the - "driver" that makes all the other libraries work together.

- -

The developers of Clang include contributers from Apple and numerous - other volunteers.

The goal of the Clang project is to create a new C, C++, Objective C and + Objective C++ front-end for the LLVM + compiler.

Why?

The development of a new front-end was started out of a need -- a need for a compiler that allows better diagnostics, better integration with IDEs, a license that is compatible with commercial products, and a compiler that is easier to develop and maintain. All of these were motivations for starting work on a new C/C++/ObjC front-end that could meet these needs. -

An excellent introduction to Clang can be found in the following video lectures: + +

The development of a new front-end was started out of a need -- a need + for a compiler that allows better diagnostics, better integration with + IDEs, a license that is compatible with commercial products, and a + compiler that is easier to develop and maintain. All of these were + motivations for starting work on a new front-end that could + meet these needs.

+ +

An good (but quite dated) introduction to Clang can be found in the + following video lectures:

Clang Introduction -
Features and Performance of Clang + (May 2007)
Features and Performance of + Clang (July 2007)

Features/Goals

- Some of the goals for the project include the following: + +

Some of the goals for the project include the following:

Real-world, production quality compiler.
A single unified parser for C/ObjC/C++
Language conformance with C, ObjC, C++ (including variants, like C90, C99, etc)
GCC compatibility (supports GCC extensions, but allow them to be disabled)
Library based architecture with finely crafted C++ APIs
High performance
Design for integration with IDEs as well as code generation with LLVM.
Expressive diagnostics
BSD License
Real-world, production quality compiler.
A single unified parser for C, Objective C, C++, and Objective + C++.
Language conformance with these languages and their variants, like + C90, C99, etc.
GCC compatibility: support GCC extensions, but allow them to be + disabled.
Library based architecture with finely crafted APIs.
Support many clients, such as refactoring, static analysis, as well as + code generation.
High performance.
Design for integration with IDEs as well as code generation with the + LLVM Optimizer and Code Generator.
Expressive diagnostics: + warnings and errors that are actually helpful and make sense.
Use the LLVM 'BSD' + License.

- Of course this is only a rough outline of the goals and features of Clang. To get a true sense of what the new LLVM front-end is all about, as well as why you might want to considering using it, see the Features section. -

Try Clang

- If you are a compiler developer and want to try out Clang, then build instructions are available on the Get Involved page. Note that clang is still early in development. If you are looking for source analysis or source-to-source transformation tools, clang is probably a great solution for you. If you want to use it as a drop in C compiler, it is not yet ready. + +

Of course this is only a rough outline of the goals and features of + Clang. To get a true sense of what the new LLVM front-end is all about, + as well as why you might want to considering using it, see the Features section.

+ + +

Current Status

+ +

Clang is still in early development stages. If you are looking for + source analysis or source-to-source transformation tools, clang is probably + a great solution for you. If you want to use it as a drop in C compiler, it + is not yet ready.

+ +

Clang currently has pretty good parsing and semantic analysis support for + C and Objective-C right now, and bugs are usually quickly fixed once + reported. C++ support is still very early, and we don't expect to have + respectable C++ support for another 2 years or so.

Get Involved

- If you are interested in working on Clang, then check out the Get Involved section. + +

The developers of Clang include contributers from Apple and numerous + other volunteers. If you are interested in joining the community or + learning more, please consider joining the cfe-dev + mailing list, or start by browsing its archives.

+ +

If you are interested in trying out Clang, please see the build + instructions on the Get Involved + page.