Build

Some distributions package a pre-built version of ccls. See the system-specific sections below. If you build ccls from source, you will need:

CMake 3.8 or higher.
A C++ compiler with C++17 support:
- Clang 5 or higher.
- GNU GCC 7.2 or higher (optional,string_view require libstdc++7 or higher)
- MSVC 2017 or higher (included with VS2017 Build Tools)
On POSIX systems, either GNU Make or Ninja (optional on other systems)
Clang+LLVM headers and libraries, version >= 7 (0.20181225.8 is the last release that supports clang 6)

The simplest/quickest build with all defaults (only for POSIX systems) is:

git clone --depth=1 --recursive https://github.com/MaskRay/ccls
cd ccls

# Download "Pre-Built Binaries" from https://releases.llvm.org/download.html
# and unpack to /path/to/clang+llvm-xxx.
# Do not unpack to a temporary directory, as the clang resource directory is hard-coded
# into ccls at compile time!
# See https://github.com/MaskRay/ccls/wiki/FAQ#verify-the-clang-resource-directory-is-correct
cmake -H. -BRelease -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=/path/to/clang+llvm-xxx
cmake --build Release

For mac users with brew

brew info llvm
cmake -H. -BRelease -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=/usr/local/Cellar/llvm/<Your Version>/lib/cmake
cmake --build Release

source

Ubuntu 18.04 prebuilt binaries are actually suitable for many non-Ubuntu distributions. You may replace the last two cmake commands with:

wget -c http://releases.llvm.org/8.0.0/clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz
tar xf clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz
cmake -H. -BRelease -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=$PWD/clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04
cmake --build Release

The resulting executable will be Release/ccls. If you forgot to pass --recursive when cloning the repo, git submodule update --init to clone the rapidjson repository.

If you compile ccls with GCC 8.2.1, append -DCMAKE_CXX_FLAGS=-fno-gnu-unique. See https://github.com/MaskRay/ccls/issues/363#issuecomment-482625854 for details.

See below for other CMake options available for customizing the build, hints for your system, as well as methods of obtaining and locating Clang+LLVM.

CMake Options

-G ('Unix Makefiles'|Ninja|Xcode|'Visual Studio 2017 x64')

Choose a specific CMake generator (build tool). Use cmake --help to see your choices (not all options are available on all systems). If not specified CMake will choose an appropriate option for your system.
-DCMAKE_BUILD_TYPE=(Debug|MinSizeRel|Release|RelWithDebInfo)

Default: Release

Set the build type. The most important ones are Debug and Release.
-DCMAKE_CXX_COMPILER=<compiler>

Build ccls with the C++ compiler <compiler>. If not specified CMake will search for an appropriate C++ compiler.
-DCMAKE_CXX_FLAGS=<flags>

Use extra compiler flags <flags> when compiling ccls. See the system-specific sections below for some suggestions.
-DCMAKE_INSTALL_PREFIX=<dir>

Default: /usr/local

Set the install location. See Install for more details.
-DCMAKE_PREFIX_PATH=<path>

Specify paths where CMake can locate Clang/LLVM headers and libraries. CMake searches the paths in CMAKE_PREFIX_PATH for include and lib.
-DUSE_SYSTEM_RAPIDJSON=(ON|OFF)

Default: ON

Use system rapidjson (usually available at /usr/include/rapidjson). If OFF or not found, third_party/rapidjson will be used instead.

Choosing Clang+LLVM

System Clang+LLVM

If your system Clang+LLVM is sufficiently new, consider using them. If they are installed into the standard locations for our system, CMAKE_PREFIX_PATH is not required.

A simple cmake -GNinja -H. -BRelease (remove -GNinja if you don't use Ninja) works for many distributions. The required system packages are:

Arch Linux: clang llvm
Fedora Linux: clang clang-devel llvm-devel
Gentoo Linux: clang
Void Linux

Prebuilt Clang+LLVM binaries

Pick the one on https://releases.llvm.org/download.html that suits your system. Note, the Ubuntu 16.04 prebuit binaries are actually suitable for many non-Ubuntu distributions.

After unpacking, cmake -GNinja -H. -BRelease -DCMAKE_PREFIX_PATH=/path/to/clang+llvm-7.0.1-x86_64-linux-gnu-ubuntu-16.04

The Windows prebuilt binaries lack C++ header files, thus they cannot be used.

System specific notes

On GNU/Linux distributions with older versions of glibc (older than 2013-04-25), such as Red Hat EL 6.x, append -DCMAKE_CXX_FLAGS=-D__STDC_FORMAT_MACROS

Arch Linux

Arch User Repository: aur/ccls-git.

extra/clang and extra/llvm provide /usr/lib/{libclangAST.so,libLLVM*.a,libLLVM.so}. libclangAST.so needs libLLVM.so and there would be a conflict if libLLVM*.a (instead of libLLVM.so) are linked. See https://bugs.archlinux.org/task/60512

Also you can install ccls from the Community repo using pacman.

sudo pacman -S ccls

Debian

# bullseye/11 and later
sudo apt install ccls

# build from source
sudo apt install clang cmake libclang-dev llvm-dev rapidjson-dev
cmake -H. -BRelease
cmake --build Release

Fedora

Available for Fedora 29 and later.

sudo dnf install ccls

openSUSE Tumbleweed

Available in openSUSE Tumbleweed

sudo zypper install ccls

Gentoo

Available in Gentoo

sudo emerge dev-util/ccls

Ubuntu

To build from source you'll need sudo apt install zlib1g-dev libncurses-dev. To use system rapidjson, install rapidjson-dev.

On Ubuntu 16.04 install g++-7 via these directions

To build with system Clang+LLVM: sudo apt install clang libclang-dev

cmake -H. -BRelease -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_PREFIX_PATH=/usr/lib/llvm-7 \
    -DLLVM_INCLUDE_DIR=/usr/lib/llvm-7/include \
    -DLLVM_BUILD_INCLUDE_DIR=/usr/include/llvm-7/

Notice that LLVM_INCLUDE_DIR points to /usr/lib, and LLVM_BUILD_INCLUDE points to /usr/include.

Build as normal. You'll have a ccls library that will be compiled against the sytem-installed LLVM, and use the system clang resource directory as well.

If you see the error:

error while loading shared libraries: libtinfo.so.5: cannot open shared object file: No such file or directory

Then installing libncurses5 with sudo apt install libncurses5 can fix the problem.

Red Hat / CentOS

Older versions (6.x) use an older GNU libc which requires -DCMAKE_CXX_FLAGS=-D__STDC_FORMAT_MACROS

MacOS

To install ccls with Homebrew:

brew update
brew install ccls

To build from source you need MacOS 10.12 (Sierra) or higher to get a version of Xcode with a sufficiently-new Clang.

To build using MacPorts Clang add CMake flags

-DCMAKE_CXX_COMPILER=clang++-mp-6.0
-DCMAKE_PREFIX_PATH=/opt/local/libexec/llvm-6.0

See https://github.com/MaskRay/ccls/issues/512 , use a shell script wrapper:

#!/bin/sh
exec /path/to/ccls/Release/ccls -init='{"clang":{"extraArgs":["-isystem", "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include"]}}' "$@"

With clang < 8, "-isystem", "/Library/Developer/CommandLineTools/usr/include/c++/v1" is also needed (https://github.com/MaskRay/ccls/issues/191#issuecomment-453809905)

With most recent MacOSs(e.g. Catalina 10.15.2), one more clang.extraArgs is needed to make ccls work properly (https://github.com/MaskRay/ccls/issues/512#issuecomment-545575369)

FreeBSD

devel/ccls
With devel/llvm90 add CMake flags -DCMAKE_PREFIX_PATH=/usr/local/llvm90
Use the releases.llvm.org prebuilt archive.

GuixSD (0.16)

guix package -i cmake clang gcc-toolchain
cmake -H. -BRelease -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=/home/$USER/.guix-profile/bin/clang
cmake --build Release

Windows

The Windows archive on releases.llvm.org does not contain library headers. Since ccls uses Clang C++ APIs, it is not possible to build ccls with these releases. You must either:

Build clang+llvm by yourself
Get prebuilt LLVM+Clang from other sources, e.g. MSYS2, Chocolatey.

Build clang+llvm by yourself

Note: You may need to execute these commands in the "Developer Command Prompt for VS"

git clone https://github.com/llvm/llvm-project.git
cd llvm-project

cmake -Hllvm -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=cl -DCMAKE_CXX_COMPILER=cl -DLLVM_TARGETS_TO_BUILD=X86 -DLLVM_ENABLE_PROJECTS=clang
ninja -C Release clangFormat clangFrontendTool clangIndex clangTooling clang

# Download ccls
cd ccls
cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang-cl -DCMAKE_PREFIX_PATH="D:/llvm/Release;D:/llvm/Release/tools/clang;D:/llvm;D:/llvm/tools/clang"
ninja -C Release

MSYS2

For 2, one possible way is use MSYS2, in MSYS2 MinGW 64-bit shell:

pacman -S mingw-w64-x86_64-clang mingw-w64-x86_64-clang-tools-extra mingw64/mingw-w64-x86_64-polly mingw-w64-x86_64-cmake mingw-w64-x86_64-jq mingw-w64-x86_64-ninja mingw-w64-x86_64-ncurses
cmake -H. -BRelease -G Ninja -DCMAKE_CXX_FLAGS=-D__STDC_FORMAT_MACROS
ninja -C Release

-D__STDC_FORMAT_MACROS is because otherwise mingw-w64-headers/crt/inttypes.h does not define PRIu64.

Build Clang+LLVM from the git monorepo

git clone https://github.com/llvm/llvm-project.git
cd llvm-project

cmake -Hllvm -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD=X86
ninja -C Release clangFormat clangFrontendTool clangIndex clangTooling clang
# built Release/bin/clang

LLVM_TARGETS_TO_BUILD defaults to ALL. We just use the frontend, don't generate code, so X86 should be sufficient. clang -target powerpc64le-linux -fsyntax-only still works.
Add -DLLVM_ENABLE_LLD=on if you have lld (a much faster linker than bfd/gold) installed
Add -DBUILD_SHARED_LIBS=on if you want to build shared libraries (libclangIndex.so)

Then build ccls with -DCMAKE_PREFIX_PATH:

cd ~/ccls
LLVM=$HOME/llvm-project
cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=lld -DCMAKE_PREFIX_PATH="$LLVM/Release;$LLVM/llvm;$LLVM/clang"
ninja -C Release

-DCMAKE_PREFIX_PATH= is a ;-separated list where you can find:

llvm: llvm source
llvm/tools/clang: clang source
llvm/Release: build directory. include/ contains generated llvm header files, e.g. include/llvm/Config/config.h
llvm/Release/tools/clang: build directory. include/ contains generated clang header files, e.g. include/clang/Config/config.h

The cmake build system is expected to find these files:

# generated clang+llvm header files
~/llvm/Release/include/llvm/Config/config.h
~/llvm/Release/tools/clang/include/clang/Config/config.h
# libclangIndex.so
~/llvm/Release/lib/libclangIndex.so or libclangIndex.a
# -resource-dir
~/llvm/Release/lib/clang/7.0.0
# clang+llvm libraries
~/llvm/Release/lib/libclangDriver.so
~/llvm/Release/lib/libLLVMSupport.so or libLLVMSupport.a
...

Build Clang+LLVM from releases.llvm.org or prereleases.llvm.org

Similar to the instructions to build Clang+LLVM from the git monorepo:

# Download "LLVM source code" and rename the extracted directory to llvm
# Download "Clang source code" and rename the extracted directory to llvm/tools/clang
cd llvm
cmake -H. -BRelease -G Ninja -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD=X86
ninja -C Release clangFormat clangFrontendTool clangIndex clangTooling clang
# built Release/bin/clang

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