Cross compilation of Qt6.5.1 for RPI

This page shows steps to compile Qt6.5.1 for RPI. Hope this page will help those stuck at following official tutorial. Before start, it is highly recommended that you use the same Ubuntu 22.04. At least not the older one.

Click the follow image to view this tutorial on Youtube.

• Cross Compilation https://youtu.be/8kpHgNKPooc
• Remote Debugging https://youtu.be/QWz-4R4kMIo
• Localization https://youtu.be/JtTtzYZ_Nk0

Prepare RPI

Install the lastest 64bit Raspberry Pi OS with desktop and update the system.

sudo apt update
sudo apt upgrade
sudo reboot

Install necessary packages.

sudo apt-get install libboost-all-dev libudev-dev libinput-dev libts-dev libmtdev-dev libjpeg-dev libfontconfig1-dev libssl-dev libdbus-1-dev libglib2.0-dev libxkbcommon-dev libegl1-mesa-dev libgbm-dev libgles2-mesa-dev mesa-common-dev libasound2-dev libpulse-dev gstreamer1.0-omx libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev  gstreamer1.0-alsa libvpx-dev libsrtp2-dev libsnappy-dev libnss3-dev "^libxcb.*" flex bison libxslt-dev ruby gperf libbz2-dev libcups2-dev libatkmm-1.6-dev libxi6 libxcomposite1 libfreetype6-dev libicu-dev libsqlite3-dev libxslt1-dev 

sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libx11-dev freetds-dev libsqlite3-dev libpq-dev libiodbc2-dev firebird-dev libxext-dev libxcb1 libxcb1-dev libx11-xcb1 libx11-xcb-dev libxcb-keysyms1 libxcb-keysyms1-dev libxcb-image0 libxcb-image0-dev libxcb-shm0 libxcb-shm0-dev libxcb-icccm4 libxcb-icccm4-dev libxcb-sync1 libxcb-sync-dev libxcb-render-util0 libxcb-render-util0-dev libxcb-xfixes0-dev libxrender-dev libxcb-shape0-dev libxcb-randr0-dev libxcb-glx0-dev libxi-dev libdrm-dev libxcb-xinerama0 libxcb-xinerama0-dev libatspi2.0-dev libxcursor-dev libxcomposite-dev libxdamage-dev libxss-dev libxtst-dev libpci-dev libcap-dev libxrandr-dev libdirectfb-dev libaudio-dev libxkbcommon-x11-dev gdbserver

Make a folder for qt6 installation.

sudo mkdir /usr/local/qt6

Grant full access to the fold used for the deployment from Qt Creator.

sudo chmod 777 /usr/local/bin

Remember versions of gcc(10.2.1), ld(2.35.2) and ldd(2.31). Source code of the same version should be downloaded to build cross compiler later.

Append following piece of code to the end of ~/.bashrc.

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/qt6/lib/

Update the changes.

source ~/.bashrc

Prepare host

Create a virtual machine for Ubuntu 22.04.2 and then update the system.

sudo apt update
sudo apt upgrade

Install necessary packages.

sudo apt-get install make build-essential libclang-dev ninja-build gcc git bison python3 gperf pkg-config libfontconfig1-dev libfreetype6-dev libx11-dev libx11-xcb-dev libxext-dev libxfixes-dev libxi-dev libxrender-dev libxcb1-dev libxcb-glx0-dev libxcb-keysyms1-dev libxcb-image0-dev libxcb-shm0-dev libxcb-icccm4-dev libxcb-sync-dev libxcb-xfixes0-dev libxcb-shape0-dev libxcb-randr0-dev libxcb-render-util0-dev libxcb-util-dev libxcb-xinerama0-dev libxcb-xkb-dev libxkbcommon-dev libxkbcommon-x11-dev libatspi2.0-dev libgl1-mesa-dev libglu1-mesa-dev freeglut3-dev build-essential gawk git texinfo bison file wget libssl-dev gdbserver gdb-multiarch libxcb-cursor-dev

Build the lastest CMake from source

cd ~
git clone https://github.com/Kitware/CMake.git
cd CMake
./bootstrap && make -j8&& sudo make install

Folder CMake is not need any more. You can delete it.

Build gcc as a cross compiler

Download necessary source code. You should modify the following commands to your needs. For the time I make this page, they are:

• gcc 10.3.0(gcc version 10.2.1 does not exist and use the closest one)
• binutils 2.35.2(ld version)
• glibc 2.31(ldd version)

  cd ~
  mkdir gcc_all && cd gcc_all
  wget https://ftpmirror.gnu.org/binutils/binutils-2.35.2.tar.bz2
  wget https://ftpmirror.gnu.org/glibc/glibc-2.31.tar.bz2
  wget https://ftpmirror.gnu.org/gcc/gcc-10.3.0/gcc-10.3.0.tar.gz
  git clone --depth=1 https://github.com/raspberrypi/linux
  tar xf binutils-2.35.2.tar.bz2
  tar xf glibc-2.31.tar.bz2
  tar xf gcc-10.3.0.tar.gz
  rm *.tar.*
  cd gcc-10.3.0
  contrib/download_prerequisites

  Make a folder for the compiler installation.

  sudo mkdir -p /opt/cross-pi-gcc
  sudo chown $USER /opt/cross-pi-gcc
  export PATH=/opt/cross-pi-gcc/bin:$PATH

  Copy the kernel headers in the above folder.

  cd ~/gcc_all
  cd linux
  KERNEL=kernel7
  make ARCH=arm64 INSTALL_HDR_PATH=/opt/cross-pi-gcc/aarch64-linux-gnu headers_install

  Build Binutils. You should modify the following commands to your needs.

  cd ~/gcc_all
  mkdir build-binutils && cd build-binutils
  ../binutils-2.35.2/configure --prefix=/opt/cross-pi-gcc --target=aarch64-linux-gnu --with-arch=armv8 --disable-multilib
  make -j 8
  make install

  Edit gcc-10.3.0/libsanitizer/asan/asan_linux.cpp. Add following piece of code.

  #ifndef PATH_MAX
  #define PATH_MAX 4096
  #endif

Do a partial build of gcc. You should modify the following commands to your needs.

cd ~/gcc_all
mkdir build-gcc && cd build-gcc
../gcc-10.3.0/configure --prefix=/opt/cross-pi-gcc --target=aarch64-linux-gnu --enable-languages=c,c++ --disable-multilib
make -j8 all-gcc
make install-gcc

Partially build Glibc. You should modify the following commands to your needs.

cd ~/gcc_all
mkdir build-glibc && cd build-glibc
../glibc-2.31/configure --prefix=/opt/cross-pi-gcc/aarch64-linux-gnu --build=$MACHTYPE --host=aarch64-linux-gnu --target=aarch64-linux-gnu --with-headers=/opt/cross-pi-gcc/aarch64-linux-gnu/include --disable-multilib libc_cv_forced_unwind=yes
make install-bootstrap-headers=yes install-headers
make -j8 csu/subdir_lib
install csu/crt1.o csu/crti.o csu/crtn.o /opt/cross-pi-gcc/aarch64-linux-gnu/lib
aarch64-linux-gnu-gcc -nostdlib -nostartfiles -shared -x c /dev/null -o /opt/cross-pi-gcc/aarch64-linux-gnu/lib/libc.so
touch /opt/cross-pi-gcc/aarch64-linux-gnu/include/gnu/stubs.h

Back to gcc.

cd ~/gcc_all/build-gcc
make -j8 all-target-libgcc
make install-target-libgcc

Finish building glibc.

cd ~/gcc_all/build-glibc
make -j8
make install

Finish building gcc.

cd ~/gcc_all/build-gcc
make -j8
make install

At this point, we have a full cross compiler toolchain with gcc. Folder gcc_all is not need any more. You can delete it.

Building Qt6

Make folders for sysroot and qt6.

cd ~
mkdir rpi-sysroot rpi-sysroot/usr rpi-sysroot/opt
mkdir qt6 qt6/host qt6/pi qt6/host-build qt6/pi-build qt6/src

Download QtBase source code

cd ~/qt6/src
wget https://download.qt.io/official_releases/qt/6.5/6.5.1/submodules/qtbase-everywhere-src-6.5.1.tar.xz
tar xf qtbase-everywhere-src-6.5.1.tar.xz

Build Qt6 for host

cd $HOME/qt6/host-build/
cmake ../src/qtbase-everywhere-src-6.5.1/ -GNinja -DCMAKE_BUILD_TYPE=Release -DQT_BUILD_EXAMPLES=OFF -DQT_BUILD_TESTS=OFF -DCMAKE_INSTALL_PREFIX=$HOME/qt6/host
cmake --build . --parallel 8
cmake --install .

Binaries will be in $HOME/qt6/host

Build Qt6 for rpi

copy and paste a few folders from rpi using rsync through SSH. You should modify the following commands to your needs.

cd ~
rsync -avz --rsync-path="sudo rsync" pi@192.168.6.218:/usr/include rpi-sysroot/usr
rsync -avz --rsync-path="sudo rsync" pi@192.168.6.218:/lib rpi-sysroot
rsync -avz --rsync-path="sudo rsync" pi@192.168.6.218:/usr/lib rpi-sysroot/usr 
rsync -avz --rsync-path="sudo rsync" pi@192.168.6.218:/opt/vc rpi-sysroot/opt

Create a file named toolchain.cmake in $HOME/qt6.

cmake_minimum_required(VERSION 3.18)
include_guard(GLOBAL)

set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR arm)

# You should change location of sysroot to your needs.
set(TARGET_SYSROOT /home/pmy/rpi-sysroot)
set(TARGET_ARCHITECTURE aarch64-linux-gnu)
set(CMAKE_SYSROOT ${TARGET_SYSROOT})

set(ENV{PKG_CONFIG_PATH} $PKG_CONFIG_PATH:${CMAKE_SYSROOT}/usr/lib/${TARGET_ARCHITECTURE}/pkgconfig)
set(ENV{PKG_CONFIG_LIBDIR} /usr/lib/pkgconfig:/usr/share/pkgconfig/:${TARGET_SYSROOT}/usr/lib/${TARGET_ARCHITECTURE}/pkgconfig:${TARGET_SYSROOT}/usr/lib/pkgconfig)
set(ENV{PKG_CONFIG_SYSROOT_DIR} ${CMAKE_SYSROOT})

set(CMAKE_C_COMPILER /opt/cross-pi-gcc/bin/${TARGET_ARCHITECTURE}-gcc)
set(CMAKE_CXX_COMPILER /opt/cross-pi-gcc/bin/${TARGET_ARCHITECTURE}-g++)

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -isystem=/usr/include -isystem=/usr/local/include -isystem=/usr/include/${TARGET_ARCHITECTURE}")
set(CMAKE_CXX_FLAGS "${CMAKE_C_FLAGS}")

set(QT_COMPILER_FLAGS "-march=armv8-a")
set(QT_COMPILER_FLAGS_RELEASE "-O2 -pipe")
set(QT_LINKER_FLAGS "-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed -Wl,-rpath-link=${TARGET_SYSROOT}/usr/lib/${TARGET_ARCHITECTURE} -Wl,-rpath-link=$HOME/qt6/pi/lib")

set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
set(CMAKE_BUILD_RPATH ${TARGET_SYSROOT})

include(CMakeInitializeConfigs)

function(cmake_initialize_per_config_variable _PREFIX _DOCSTRING)
  if (_PREFIX MATCHES "CMAKE_(C|CXX|ASM)_FLAGS")
    set(CMAKE_${CMAKE_MATCH_1}_FLAGS_INIT "${QT_COMPILER_FLAGS}")

    foreach (config DEBUG RELEASE MINSIZEREL RELWITHDEBINFO)
      if (DEFINED QT_COMPILER_FLAGS_${config})
        set(CMAKE_${CMAKE_MATCH_1}_FLAGS_${config}_INIT "${QT_COMPILER_FLAGS_${config}}")
      endif()
    endforeach()
  endif()

  if (_PREFIX MATCHES "CMAKE_(SHARED|MODULE|EXE)_LINKER_FLAGS")
    foreach (config SHARED MODULE EXE)
      set(CMAKE_${config}_LINKER_FLAGS_INIT "${QT_LINKER_FLAGS}")
    endforeach()
  endif()

  _cmake_initialize_per_config_variable(${ARGV})
endfunction()

set(XCB_PATH_VARIABLE ${TARGET_SYSROOT})

set(GL_INC_DIR ${TARGET_SYSROOT}/usr/include)
set(GL_LIB_DIR ${TARGET_SYSROOT}:${TARGET_SYSROOT}/usr/lib/${TARGET_ARCHITECTURE}/:${TARGET_SYSROOT}/usr:${TARGET_SYSROOT}/usr/lib)

set(EGL_INCLUDE_DIR ${GL_INC_DIR})
set(EGL_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/${TARGET_ARCHITECTURE}/libEGL.so)

set(OPENGL_INCLUDE_DIR ${GL_INC_DIR})
set(OPENGL_opengl_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/${TARGET_ARCHITECTURE}/libOpenGL.so)

set(GLESv2_INCLUDE_DIR ${GL_INC_DIR})
set(GLIB_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/${TARGET_ARCHITECTURE}/libGLESv2.so)

set(GLESv2_INCLUDE_DIR ${GL_INC_DIR})
set(GLESv2_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/${TARGET_ARCHITECTURE}/libGLESv2.so)

set(gbm_INCLUDE_DIR ${GL_INC_DIR})
set(gbm_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/${TARGET_ARCHITECTURE}/libgbm.so)

set(Libdrm_INCLUDE_DIR ${GL_INC_DIR})
set(Libdrm_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/${TARGET_ARCHITECTURE}/libdrm.so)

set(XCB_XCB_INCLUDE_DIR ${GL_INC_DIR})
set(XCB_XCB_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/${TARGET_ARCHITECTURE}/libxcb.so)

list(APPEND CMAKE_LIBRARY_PATH ${CMAKE_SYSROOT}/usr/lib/${TARGET_ARCHITECTURE})
list(APPEND CMAKE_PREFIX_PATH "/usr/lib/${TARGET_ARCHITECTURE}/cmake")

Fix absolute symbolic links

cd ~
wget https://raw.githubusercontent.com/riscv/riscv-poky/master/scripts/sysroot-relativelinks.py
chmod +x sysroot-relativelinks.py 
python3 sysroot-relativelinks.py rpi-sysroot

Compile source code for rpi.

cd $HOME/qt6/pi-build
cmake ../src/qtbase-everywhere-src-6.5.1/ -GNinja -DCMAKE_BUILD_TYPE=Release -DINPUT_opengl=es2 -DQT_BUILD_EXAMPLES=OFF -DQT_BUILD_TESTS=OFF -DQT_HOST_PATH=$HOME/qt6/host -DCMAKE_STAGING_PREFIX=$HOME/qt6/pi -DCMAKE_INSTALL_PREFIX=/usr/local/qt6 -DCMAKE_TOOLCHAIN_FILE=$HOME/qt6/toolchain.cmake -DQT_QMAKE_TARGET_MKSPEC=devices/linux-rasp-pi4-aarch64 -DQT_FEATURE_xcb=ON -DFEATURE_xcb_xlib=ON -DQT_FEATURE_xlib=ON
cmake --build . --parallel 8
cmake --install .

Send the binaries to rpi. You should modify the following commands to your needs.

rsync -avz --rsync-path="sudo rsync" $HOME/qt6/pi/* pi@192.168.6.218:/usr/local/qt6

With Qt Creator

Set up Compilers.

Set up Debuggers.

Set up Devices.

Click Deploy Public Key... to deploy the key. Create one if not existed.

Test the device.

Set up Qt Versions.

Set up Kits.

On CMake Configuration opton, click Change and add follow commands. You should modify the following commands to your needs.

-DCMAKE_TOOLCHAIN_FILE:UNINITIALIZED=/home/pmy/qt6/pi/lib/cmake/Qt6/qt.toolchain.cmake

Test HelloWorld

On Help option select About Plugins.Then uncheck ClangCodeModel(No need for Qt Creator 10 or later)..

Append following piece of code to the end of CMakeLists.txt(No need for Qt Creator 10 or later).

install(TARGETS HelloWorld
    RUNTIME DESTINATION ""
    BUNDLE DESTINATION ""
    LIBRARY DESTINATION ""
)

Goto Projects Under Run section, on X11 Forwarding check Forward to local display and input :0 to the text field.

Under Environment section, click Details to expand the environment option. Click Add, then on Variable column type LD_LIBRARY_PATH. On the Value column, type :/usr/local/qt6/lib/.

Run.

We have HelloWorld running on rpi now.

Add QML module

Download source code.

cd ~/qt6/src
wget https://download.qt.io/official_releases/qt/6.5/6.5.1/submodules/qtshadertools-everywhere-src-6.5.1.tar.xz
tar xf qtshadertools-everywhere-src-6.5.1.tar.xz
wget https://download.qt.io/official_releases/qt/6.5/6.5.1/submodules/qtdeclarative-everywhere-src-6.5.1.tar.xz
tar xf qtdeclarative-everywhere-src-6.5.1.tar.xz

You can check dependencies at ~/qt6/src/qtdeclarative-everywhere-src-6.5.1/dependencies.yaml and ~/qt6/src/qtshadertools-everywhere-src-6.5.1/dependencies.yaml Make sure required modules should be built and installed first.

Build the modules for host

cd ~/qt6/host-build
rm -rf *
$HOME/qt6/host/bin/qt-configure-module ../src/qtshadertools-everywhere-src-6.5.1
cmake --build . --parallel 8
cmake --install .
rm -rf *
$HOME/qt6/host/bin/qt-configure-module ../src/qtdeclarative-everywhere-src-6.5.1
cmake --build . --parallel 8
cmake --install .

Build the modules for rpi

cd ~/qt6/pi-build
rm -rf *
$HOME/qt6/pi/bin/qt-configure-module ../src/qtshadertools-everywhere-src-6.5.1
cmake --build . --parallel 8
cmake --install .
rm -rf *
$HOME/qt6/pi/bin/qt-configure-module ../src/qtdeclarative-everywhere-src-6.5.1
cmake --build . --parallel 8
cmake --install .

Send the binaries to rpi. You should modify the following commands to your needs.

rsync -avz --rsync-path="sudo rsync" $HOME/qt6/pi/* pi@192.168.6.218:/usr/local/qt6

Test HelloWorldQml