Clang
clang.llvm.org
Clang C Language Family Frontend for LLVM
The Clang project provides a language front-end and tooling infrastructure for languages in the C language family (C, C++, Objective C/C++, OpenCL, and CUDA) for the LLVM project. Both a GCC-compatible compiler driver (clang) and an MSVC-compatible compiler driver (clang-cl.exe) are provided.
Getting Started
This page gives you the shortest path to checking out Clang and demos a few options. This should get you up and running with the minimum of muss and fuss. If you like what you see, please consider getting involved with the Clang community. If you run into problems, please file bugs on the LLVM bug ...
Clang-Tidy
clang-tidy is a LibTooling-based tool, and it’s easier to work with if you set up a compile command database for your project (for an example of how to do this, see How To Setup Tooling For LLVM).
ClangFormat
Users calling this script directly ... insensitive, overridden by -regex) -sort-includes let clang-format sort include blocks -v, --verbose be more verbose, ineffective without -i -style STYLE formatting style to apply (LLVM, GNU, Google, Chromium, Microsoft, Mozilla, WebKit) ...
Clang Compiler User's Manual
The Clang Compiler is an open-source compiler for the C family of programming languages, aiming to be the best-in-class implementation of these languages. Clang builds on the LLVM optimizer and code generator, allowing it to provide high-quality optimization and code generation support for ...
Factsheet
Original author Chris Lattner
Developer LLVM Developer Group
Release September 26, 2007; 18 years ago (2007-09-26)
Original author Chris Lattner
Developer LLVM Developer Group
Release September 26, 2007; 18 years ago (2007-09-26)
GitHub
github.com › llvm › llvm-project
GitHub - llvm/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. · GitHub
3 days ago - This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.
Starred by 39K users
Forked by 17.6K users
Languages LLVM 41.2% | C++ 30.4% | C 12.5% | Assembly 11.2% | MLIR 1.6% | Python 0.8%
How do I unlock the true power of my LLVM clang?
Assuming you're using make or CMake, try the -j compiler flag to run multiple threads. If you have 8 cores, for example, -j8 should make your life better. More on reddit.com
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August 4, 2025ELI5-ish: LLVM vs Clang vs GCC
I've read that LLVM/Clang would be the "next generation" C compiler that offer some benefits above using GCC. This is mostly hype. LLVM/clang is more modular than GCC is. That is, it's a lot easier to use the LLVM/Clang infrastructure as a library for various purposes. A lot of tools to assist in development leverage LLVM/Clang, for instance you will have code autoformatters and error checkers that use Clang's parsing subsystems. GCC is much less modular; if you want to use GCC to turn source code into executables, that's great, but if you want it to do other things... not so much. On the other hand, GCC is still actually a better compiler than Clang/LLVM is. It producers faster code, it produces smaller code, it correctly compiles more code, (the linux kernel is a notable example) etc. There was a time in ye early days when Clang/LLVM compiled much faster than GCC, (think 10x as fast) but as Clang/LLVM added more and more optimization passes to make their finished binaries comparable to GCC's finished binaries, the compile times have bloated. It's probably still faster, but I don't have any recent benchmarks. Mesa leverages LLVM to compile shaders to your video card's native machine code formats, and Firefox uses a bit of its Servo architecture, which is written in Rust, which uses LLVM to perform optimization and translation to machine code. More on reddit.com
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August 16, 2017LLVM/Clang 10.0.0 is released!
I T S H A P P E N I N G More on reddit.com
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March 24, 2020Why you should use Clang
Ah, the missing semicolon... The only reason girls would talk to me back in the uni days. More on reddit.com
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March 3, 2010Videos
What's New in Clang and LLVM - WWDC19 - Videos - Apple Developer
19:21
Build Clang++20 (LLVM 18 and lldb) from source - YouTube
39:04
Demystifying LLVM: Writing Your First Compiler - The Good, The ...
How LLVM & Clang work
40:42
2024 LLVM Dev Mtg - State of Clang as a C and C++ Compiler - YouTube
LLVM
llvm.org
The LLVM Compiler Infrastructure Project
The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. Despite its name, LLVM has little to do with traditional virtual machines. The name "LLVM" itself is not an acronym; it is the full name of the project · LLVM began as a research project at the University ...
Wikipedia
en.wikipedia.org › wiki › Clang
Clang - Wikipedia
April 18, 2026 - Since v16.0.0, Clang compiles C++ using the GNU++17 dialect by default, which includes features from the C++17 standard and conforming GNU extensions. In 2005, Apple Inc. made extensive use of LLVM in several commercial products, including the iOS SDK and Xcode 3.1.
Microsoft Learn
learn.microsoft.com › en-us › cpp › build › clang-support-msbuild
Clang/LLVM support in Visual Studio projects | Microsoft Learn
If you're using the Clang tools that are bundled with Visual Studio, no extra steps are required. For Windows projects, Visual Studio by default invokes Clang in clang-cl mode. It links with the Microsoft implementation of the Standard Library. By default, clang-cl.exe is located in %VCINSTALLDIR%\Tools\Llvm\bin\ and %VCINSTALLDIR%\Tools\Llvm\x64\bin\.
Apple Open Source
opensource.apple.com › projects › llvm-clang
LLVM / Clang
These libraries are built around ... language (or port an existing compiler) to use LLVM as an optimizer and code generator. Clang is an "LLVM native" C/C++/Objective-C compiler, which aims to deliver amazingly fast compiles, extremely useful error and warning messages and to ...
LLVM
releases.llvm.org › download.html
LLVM Download Page
These binaries include Clang, LLD, compiler-rt, various LLVM tools, etc.
Inl
mooseframework.inl.gov › getting_started › installation › manual_installation_llvm.html
LLVM Clang from Source | MOOSE
mkdir llvm-build cd llvm-build cmake ../llvm -G 'Unix Makefiles' \ -DLLVM_ENABLE_PROJECTS='clang;clang-tools-extra;compiler-rt;libcxx;libcxxabi;libunwind;openmp;lldb' \ -DCMAKE_INSTALL_PREFIX=/target/installation/path/llvm-19 \ -DCMAKE_INSTALL_RPATH:STRING=/target/installation/path/llvm-19/lib \ -DCMAKE_INSTALL_NAME_DIR:STRING=/target/installation/path/llvm-19/lib \ -DCMAKE_BUILD_WITH_INSTALL_RPATH=1 \ -DLLVM_TARGETS_TO_BUILD="X86" \ -DCMAKE_BUILD_TYPE=Release \ -DCMAKE_MACOSX_RPATH:BOOL=OFF \ -DCMAKE_CXX_LINK_FLAGS="-L/some/path/to/gcc-13.3.1/lib64 -Wl,-rpath,/some/path/to/gcc-13.3.1/lib64" \ -DGCC_INSTALL_PREFIX=/some/path/to/gcc-13.3.1 \ -DCMAKE_CXX_COMPILER=/some/path/to/gcc-13.3.1/bin/g++ \ -DCMAKE_C_COMPILER=/some/path/to/gcc-13.3.1/bin/gcc
Inl
mooseframework.inl.gov › getting_started › installation › manual_llvm.html
LLVM Clang | MOOSE
mkdir llvm-build cd llvm-build cmake ../llvm -G 'Unix Makefiles' \ -DLLVM_ENABLE_PROJECTS='clang;clang-tools-extra;compiler-rt;libcxx;libcxxabi;libunwind;openmp;lldb' \ -DCMAKE_INSTALL_PREFIX=/target/installation/path/llvm-19 \ -DCMAKE_INSTALL_RPATH:STRING=/target/installation/path/llvm-19/lib \ -DCMAKE_INSTALL_NAME_DIR:STRING=/target/installation/path/llvm-19/lib \ -DCMAKE_BUILD_WITH_INSTALL_RPATH=1 \ -DLLVM_TARGETS_TO_BUILD="X86" \ -DCMAKE_BUILD_TYPE=Release \ -DCMAKE_MACOSX_RPATH:BOOL=OFF \ -DCMAKE_CXX_LINK_FLAGS="-L/some/path/to/gcc-13.3.1/lib64 -Wl,-rpath,/some/path/to/gcc-13.3.1/lib64" \ -DGCC_INSTALL_PREFIX=/some/path/to/gcc-13.3.1 \ -DCMAKE_CXX_COMPILER=/some/path/to/gcc-13.3.1/bin/g++ \ -DCMAKE_C_COMPILER=/some/path/to/gcc-13.3.1/bin/gcc
Clang
clang.llvm.org › get_started.html
Clang - Getting Started
You can download the release versions from https://llvm.org/releases/. Clang is also provided in all major BSD or GNU/Linux distributions as part of their respective packaging systems.
Visual Studio Code
code.visualstudio.com › docs › cpp › config-clang-mac
Using Clang in Visual Studio Code
November 3, 2021 - In this tutorial, you configure Visual Studio Code on macOS to use the Clang/LLVM compiler and debugger.
Clang
clang.org
clang: C++ Compiler
clang 3.5 is here · featuring C++14 support · Get Started Downloads C++14/C++1y Status Report a Bug Get Involved Planet Clang
Medium
alibabatech.medium.com › gcc-vs-clang-llvm-an-in-depth-comparison-of-c-c-compilers-899ede2be378
GCC vs. Clang/LLVM: An In-Depth Comparison of C/C++ Compilers | by Alibaba Tech | Medium
December 27, 2019 - Visual C++, GNU Compiler Collection (GCC), and Clang/Low Level Virtual Machine (LLVM) are three mainstream C/C++ compilers in the industry. Visual C++ provides graphical user interfaces (GUIs) and is easy to debug, but it is not suitable for ...
LLVM
llvm.org › docs
About — LLVM 23.0.0git documentation
The LLVM compiler infrastructure supports a wide range of projects, from industrial strength compilers to specialized JIT applications to small research projects.
Red Hat
docs.redhat.com › en › documentation › red_hat_developer_tools › 2019.1 › html › using_clang_and_llvm_toolset › chap-llvm-intro
Chapter 1. Clang and LLVM Toolset | Using Clang and LLVM Toolset | Red Hat Developer Tools | 2019.1 | Red Hat Documentation
Clang and LLVM Toolset is distributed as a collection of RPM packages that can be installed, updated, uninstalled, and inspected by using the standard package management tools that are included in Red Hat Enterprise Linux. Note that a valid subscription that provides access to the Red Hat Developer Tools content set is required in order to install Clang and LLVM Toolset on your Red Hat Enterprise Linux 7 system.
LLVM
llvm.org › docs › UserGuides.html
User Guides — LLVM 23.0.0git documentation
Instructions for building the clang front-end from source. ... This describes the format and encoding used for LLVM’s code coverage mapping.
GitHub
github.com › topics › llvm-clang
llvm-clang · GitHub Topics · GitHub
docker-image clang-format clang-tidy code-formatter llvm-clang clang-tools-extra clang-tool llvm-tools cpp-linter
Medium
can-ozkan.medium.com › demystifying-llvm-and-clang-a-modern-compiler-infrastructure-67abb2640b33
Demystifying LLVM and Clang: A Modern Compiler Infrastructure | by Can Özkan | Medium
July 14, 2025 - It is designed around an intermediate ... platform-agnostic format. Clang, on the other hand, is a frontend for LLVM that specifically supports C, C++, and Objective-C....
LLVM
releases.llvm.org › 10.0.0 › docs › GettingStarted.html
Getting Started with the LLVM System — LLVM 10 documentation
March 24, 2020 - The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and converts it into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.
Reddit
reddit.com › r/cpp_questions › how do i unlock the true power of my llvm clang?
r/cpp_questions on Reddit: How do I unlock the true power of my LLVM clang?
August 4, 2025 -
Hi all,
So I recently got a new Macbook Pro M4 laptop with 48 GB RAM. I have a simulation code that is template heavy and experiences a sort of template explosion. I did primary development on my macbook pro for a while, but now have ported the code over to my Asus ROG laptop with an NVIDIA GPU in it for further acceleration. Something I noticed immediately was that when enabling the full instantiation stack to compile on the M4, this took ~1 hr to complete. I sort of shrugged at this and said "ok I'll figure out how to get around this template explosion later" and would only instantiate the templates I needed at the time of development. However, when I ported everything to my older ROG laptop and compiled it to allow all of the ~180 template instantiations (it's a hydrodynamics code with different requirements for mesh geometries, dimensionality of the problem, etc), I found that everything compiled in about 2 minutes.
I'm fairly new to developing on macOS, but this seems egregious, no? on the macbook I'm compiling with llvm clang version 20.1.8 with the lld (I've also tried ld64) linker. On the ROG I compile with gcc 15 with the ld.bfd linker. I notice that the timecommand shows that the ROG linux machine uses about 500% cpu (~avg of 5 cores on a 16 core machine) during the build while the apple machine uses only a single core (a total of 12 cores on the machine) the entire time. I'm using the meson build system and the build configurations file is identical between both machines. So as a sort of sanity check I installed gcc-15 onto the macbook pro. I immediately saw 2min compilation times. This is where I'm lost. even when gcc uses the ld64 linker, we get much faster linking where I see a spike in cpu usage in btop hit 100% core usage during the link step. I have been searching around, but I'm not sure how to enable llvm clang's "performance mode." this difference seems large enough that it's likely my own ignorance to the llvm build system that's causing such discrepancies in compilation time. Any advice would be greatly appreciated! Thank you all for reading!
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Assuming you're using make or CMake, try the -j compiler flag to run multiple threads. If you have 8 cores, for example, -j8 should make your life better.
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can you try clang on your other machine too? That would tell you whether it's a problem with clang in general or something more specific to your setup on macOS.