ladybird/Documentation/BuildInstructionsLadybird.md

Ladybird browser build instructions

Build Prerequisites

Qt6 development packages, FFmpeg, nasm, additional build tools, and a C++23 capable compiler like g++-13 or clang-17 are required.

CMake 3.25 or newer must be available in $PATH.

Note

In all of the below lists of packages, the Qt6 multimedia package is not needed if your Linux system supports PulseAudio.

---

Debian/Ubuntu:

sudo apt install autoconf autoconf-archive automake build-essential ccache cmake curl fonts-liberation2 git libavcodec-dev libavformat-dev libgl1-mesa-dev nasm ninja-build pkg-config qt6-base-dev qt6-tools-dev-tools qt6-wayland tar unzip zip

CMake 3.25 or newer:

• Recommendation: Install CMake 3.25 or newer from Kitware's apt repository:

Note

This repository is Ubuntu-only

# Add Kitware GPG signing key
wget -O - https://apt.kitware.com/keys/kitware-archive-latest.asc 2>/dev/null | gpg --dearmor - | sudo tee /usr/share/keyrings/kitware-archive-keyring.gpg >/dev/null

# Optional: Verify the GPG key manually

# Use the key to authorize an entry for apt.kitware.com in apt sources list
echo "deb [signed-by=/usr/share/keyrings/kitware-archive-keyring.gpg] https://apt.kitware.com/ubuntu/ $(lsb_release -sc) main" | sudo tee /etc/apt/sources.list.d/kitware.list

# Update apt package list and install cmake
sudo apt update -y && sudo apt install cmake -y

C++23-capable compiler:

• Recommendation: Install clang-17 or newer from LLVM's apt repository:

# Add LLVM GPG signing key
sudo wget -O /usr/share/keyrings/llvm-snapshot.gpg.key https://apt.llvm.org/llvm-snapshot.gpg.key

# Optional: Verify the GPG key manually

# Use the key to authorize an entry for apt.llvm.org in apt sources list
echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg.key] https://apt.llvm.org/$(lsb_release -sc)/ llvm-toolchain-$(lsb_release -sc)-18 main" | sudo tee -a /etc/apt/sources.list.d/llvm.list

# Update apt package list and install clang and associated packages
sudo apt update -y && sudo apt install clang-18 clangd-18 clang-format-18 clang-tidy-18 lld-18 -y

• Alternative: Install gcc-13 or newer from Ubuntu Toolchain PPA:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test
sudo apt update && sudo apt install g++-13 libstdc++-13-dev

Audio support:

• Recommendation: Install PulseAudio development package:

sudo apt install libpulse-dev

• Alternative: Install Qt6's multimedia package:

sudo apt install qt6-multimedia-dev

Arch Linux/Manjaro:

sudo pacman -S --needed autoconf-archive automake base-devel ccache cmake curl ffmpeg libgl nasm ninja qt6-base qt6-multimedia qt6-tools qt6-wayland ttf-liberation tar unzip zip

Fedora or derivatives:

sudo dnf install autoconf-archive automake ccache cmake curl libavcodec-free-devel libavformat-free-devel liberation-sans-fonts libglvnd-devel nasm ninja-build perl-FindBin perl-IPC-Cmd qt6-qtbase-devel qt6-qtmultimedia-devel qt6-qttools-devel qt6-qtwayland-devel tar unzip zip zlib-ng-compat-static

openSUSE:

sudo zypper install autoconf-archive automake ccache cmake curl ffmpeg-7-libavcodec-devel ffmpeg-7-libavformat-devel gcc13 gcc13-c++ liberation-fonts libglvnd-devel nasm ninja qt6-base-devel qt6-multimedia-devel qt6-tools-devel qt6-wayland-devel tar unzip zip

The build process requires at least python3.7; openSUSE Leap only features Python 3.6 as default, so it is recommendable to install package python311 and create a virtual environment (venv) in this case.

NixOS or with Nix:

Note

These steps are out of date, as vcpkg does not work with Nix. Please refer to the nixpkgs package for the most up-to-date build instructions.

nix develop

# With a custom entrypoint, for example your favorite shell
nix develop --command bash

On NixOS or with Nix using your host nixpkgs and the legacy nix-shell tool:

nix-shell Ladybird

# With a custom entrypoint, for example your favorite shell
nix-shell --command bash Ladybird

macOS:

Xcode 14 versions before 14.3 might crash while building ladybird. Xcode 14.3 or clang from homebrew may be required to successfully build ladybird.

xcode-select --install
brew install autoconf autoconf-archive automake ccache cmake ffmpeg nasm ninja pkg-config

If you wish to use clang from homebrew instead:

brew install llvm

If you also plan to use the Qt chrome on macOS:

brew install qt

Windows:

• Create a WSL2 environment using one of the Linux distros listed above. Ubuntu or Fedora is recommended.

• Install the required packages for the selected Linux distro in the WSL2 environment.

WSL1 is known to have issues. If you run into problems, please use WSL2.

MinGW/MSYS2 are not supported.

Native Windows builds are not supported.

OpenIndiana:

Note that OpenIndiana's latest GCC port (GCC 11) is too old to build Ladybird, so you need Clang, which is available in the repository.

pfexec pkg install clang-17 cmake libglvnd ninja qt6

Haiku:

pkgman install cmake cmd:python3 ninja openal_devel qt6_base_devel qt6_multimedia_devel qt6_tools_devel

Android:

On a Unix-like platform, install the prerequisites for that platform and then see the Android Studio guide. Or, download a version of Gradle >= 8.0.0, and run the gradlew program in Ladybird/Android

Build steps

Using ladybird.sh

The simplest way to build and run ladybird is via the ladybird.sh script:

# From /path/to/ladybird
./Meta/ladybird.sh run ladybird

On macOS, to build using clang from homebrew:

CC=$(brew --prefix llvm)/bin/clang CXX=$(brew --prefix llvm)/bin/clang++ ./Meta/ladybird.sh run

You may also choose to start it in gdb using:

./Meta/ladybird.sh gdb ladybird

The above commands will build a Release version of Ladybird. To instead build a Debug version, run the Meta/ladybird.sh script with the value of the BUILD_PRESET environment variable set to Debug, like this:

BUILD_PRESET=Debug ./Meta/ladybird.sh run ladybird

Note that debug symbols are available in both Release and Debug builds.

The chromes

Ladybird will be built with one of the following browser chromes (graphical frontends), depending on the platform:

• AppKit - The native chrome on macOS.
• Qt - The chrome used on all other platforms.
• Android UI - The native chrome on Android.

The Qt chrome is available on platforms where it is not the default as well (except on Android). To build the Qt chrome, install the Qt dependencies for your platform, and enable the Qt chrome via CMake:

# From /path/to/ladybird
cmake --preset default -DENABLE_QT=ON

To re-disable the Qt chrome, run the above command with -DENABLE_QT=OFF.

Build error messages you may encounter

The section lists out some particular error messages you may run into, and explains how to deal with them.

Unable to find a build program corresponding to "Ninja"

Solution to try: If you do in fact already have Ninja installed, then first try reinstalling Ninja.

Details: If you see the message “Unable to find a build program corresponding to "Ninja"”, it’s likely not an indication that the build tooling can’t actually find Ninja, but instead an indication that the tooling found Ninja but it failed to run successfully.

So, when you do run into that error message, the way to start figuring out what’s actually wrong is to try invoking Ninja manually, like this:

ninja -C Build/ladybird

Then, based on what output you get from that, you can troubleshoot the actual problem you’re running into — which may involve uninstalling your current Ninja install, and then re-installing it.

Resource files

Ladybird requires resource files from the ladybird/Base/res directory in order to properly load icons, fonts, and other theming information. These files are copied into the build directory by special CMake rules. The expected location of resource files can be tweaked by packagers using the standard CMAKE_INSTALL_DATADIR variable. CMAKE_INSTALL_DATADIR is expected to be a path relative to CMAKE_INSTALL_PREFIX. If it is not, things will break.

Custom CMake build directory

The script Meta/ladybird.sh and the default preset in CMakePresets.json both define a build directory of Build/ladybird. For distribution purposes, or when building multiple configurations, it may be useful to create a custom CMake build directory.

The install rules in Ladybird/cmake/InstallRules.cmake define which binaries and libraries will be installed into the configured CMAKE_PREFIX_PATH or path passed to cmake --install.

Note that when using a custom build directory rather than Meta/ladybird.sh, the user may need to provide a suitable C++ compiler (g++ >= 13, clang >= 14, Apple Clang >= 14.3) via the CMAKE_CXX_COMPILER and CMAKE_C_COMPILER cmake options.

cmake -GNinja -B MyBuildDir
# optionally, add -DCMAKE_CXX_COMPILER=<suitable compiler> -DCMAKE_C_COMPILER=<matching c compiler>
cmake --build MyBuildDir
ninja -C MyBuildDir run-ladybird

Running manually

The Meta/ladybird.sh script will execute the run-ladybird and debug-ladybird custom targets. If you don't want to use the ladybird.sh script to run the application, you can run the following commands:

To automatically run in gdb:

ninja -C Build/ladybird debug-ladybird

To run without ninja rule on non-macOS systems:

./Build/ladybird/bin/Ladybird

To run without ninja rule on macOS:

open -W --stdout $(tty) --stderr $(tty) ./Build/ladybird/bin/Ladybird.app

# Or to launch with arguments:
open -W --stdout $(tty) --stderr $(tty) ./Build/ladybird/bin/Ladybird.app --args https://ladybird.dev

Experimental GN build

There is an experimental GN build for Ladybird. It is not officially supported, but it is kept up to date on a best-effort basis by interested contributors. See the GN build instructions for more information.

In general, the GN build organizes ninja rules in a more compact way than the CMake build, and it may be faster on some systems. GN also allows building host and cross-targets in the same build directory, which is useful for managing dependencies on host tools when cross-compiling to other platforms.

Debugging with CLion

Ladybird should be built with debug symbols first. This can be done by adding -DCMAKE_BUILD_TYPE=Debug to the cmake command line, or selecting the Build Type Debug in the CLion CMake profile.

After running Ladybird as suggested above with ./Meta/ladybird.sh run ladybird, you can now in CLion use Run -> Attach to Process to connect. If debugging layout or rendering issues, filter the listing that opens for WebContent and attach to that.

Now breakpoints, stepping and variable inspection will work.

Debugging with Xcode or Instruments on macOS

If all you want to do is use Instruments, then an Xcode project is not required.

Simply run the ladybird.sh script as normal, and then make sure to codesign the Ladybird binary with the proper entitlements to allow Instruments to attach to it.

./Meta/ladybird.sh build
 ninja -C build/ladybird apply-debug-entitlements
 # or
 codesign -s - -v -f --entitlements Meta/debug.plist Build/ladybird/bin/Ladybird.app

Now you can open the Instruments app and point it to the Ladybird app bundle.

If you want to use Xcode itself for debugging, you will need to generate an Xcode project. The ladybird.sh build script does not know how to generate Xcode projects, so creating the project must be done manually.

cmake -GXcode -B Build/ladybird

After generating an Xcode project into the specified build directory, you can open ladybird.xcodeproj in Xcode. The project has a ton of targets, many of which are generated code. The only target that needs a scheme is the ladybird app bundle.

Building on OpenIndiana

OpenIndiana needs some extra environment variables set to make sure it finds all the executables and directories it needs for the build to work. The cmake files are in a non-standard path that contains the Qt version (replace 6.2 with the Qt version you have installed) and you need to tell it to use clang and clang++, or it will use gcc and g++ from GCC 10 which is currently the default to build packages on OpenIndiana.

When running Ladybird, make sure that XDG_RUNTIME_DIR is set, or it will immediately crash as it doesn't find a writable directory for its sockets.

CMAKE_PREFIX_PATH=/usr/lib/qt/6.2/lib/amd64/cmake cmake -GNinja -B Build/ladybird -DCMAKE_C_COMPILER=/usr/bin/clang -DCMAKE_CXX_COMPILER=/usr/bin/clang++
cmake --build Build/ladybird
XDG_RUNTIME_DIR=/var/tmp ninja -C Build/ladybird run