Build Flutter engine for linux-arm/arm64

HW:

Hardkernel ODROID-N2 (https://www.hardkernel.com/product/)
Hardkernel ODROID-C4 (https://www.hardkernel.com/product/)
ODROID-VU7A+ (https://www.hardkernel.com/product/)

OS:

Ubuntu disco minimal 20191228(ODROID-N2) (http://ppa.linuxfactory.or.kr/images/raw/arm64/disco/)
Ubuntu focal server 20201024(ODROID-C4) (http://ppa.linuxfactory.or.kr/images/raw/arm64/focal/)
Ubuntu focal mate 20201020(ODROID-C4) (https://dn.odroid.com/S905X3/ODROID-C4/Ubuntu/)

caution

Make sure the command ran successfully before running the next command!!

Dependencies#

Host(Linux x86_64)#

mkdir -p $HOME/flutter-engine/sdk/toolchain \
&& mkdir -p $HOME/flutter-engine/sdk/sysroot \
&& mkdir -p $HOME/flutter-engine/engine

info

Using docker, run
docker run -it --volume="$HOME/flutter-engine:/root/flutter-engine:shared" ubuntu:18.04 /bin/bash.
Then, run apt update && apt install sudo on the container before following what is shown below.

sudo apt update -y \
&& sudo apt install -y bison build-essential cmake curl flex gcc git \
    lsb-release libgmp-dev make ninja-build pkg-config python python3 \
    rsync subversion texinfo vim wget \
&& sudo apt autoremove -y

Target(Linux ARM/ARM64)#

Connect the SD card or eMMC with OS to your SBC.

sudo apt update -y \
&& sudo apt install -y build-essential clang cmake git libblkid-dev \
    libfreetype6-dev libglib2.0-dev libgtk-3-dev liblzma-dev ninja-build \
    pkg-config rsync symlinks vim \
&& sudo apt autoremove -y

sysroot#

It may vary depending on various conditions. If symbolic links are broken, you will get some errors when following the steps below.

info

When I tested this, most of the errors occured for this reason.

Target(Linux ARM/ARM64)#

sudo symlinks -crs /*

sudo rsync -a -e 'ssh -p <host port>' /lib /usr /etc /opt \
    <host user>@<host ip>:~/flutter-engine/sdk/sysroot

Host(Linux x86_64)#

When I built all successfully, the directory structure is shown below. Since / (root) is copied to $HOME/flutter-engine/sdk/sysroot, setting a symbolic link path to an absolute path can break symbolic links.

$HOME/flutter-engine/sdk/sysroot
├── lib -> usr/lib
└── usr
    ├── include
    │   └── ...
    └── lib
        ├── aarch64-linux-gnu
        │   ├── crt1.o
        │   ├── crti.o
        │   ├── crtn.o
        │   ├── ld-2.29.so
        │   ├── ld-linux-aarch64.so.1 -> ld-2.29.so
        │   ├── libc-2.29.so
        │   ├── libc_nonshared.a
        │   ├── libc.so
        │   ├── libc.so.6 -> libc-2.29.so
        │   ├── libdl-2.29.so
        │   ├── libdl.so -> ../../../lib/aarch64-linux-gnu/libdl.so.2
        │   ├── libdl.so.2 -> libdl-2.29.so
        │   ├── libgcc_s.so.1
        │   ├── libm-2.29.so
        │   ├── libm.so -> libm.so.6
        │   ├── libm.so.6 -> libm-2.29.so
        │   ├── libpthread-2.29.so
        │   ├── libpthread.so -> ../../../lib/aarch64-linux-gnu/libpthread.so.0
        │   ├── libpthread.so.0 -> libpthread-2.29.so
        │   ├── librt-2.29.so
        │   ├── librt.so -> ../../../lib/aarch64-linux-gnu/librt.so.1
        │   ├── librt.so.1 -> librt-2.29.so
        │   ├── libstdc++.so.6 -> libstdc++.so.6.0.26
        │   └── libstdc++.so.6.0.26
        └── gcc
            └── aarch64-linux-gnu
                └── 8
                    ├── crtbegin.o
                    ├── crtbeginS.o
                    ├── crtend.o
                    ├── crtendS.o
                    ├── libgcc.a
                    ├── libgcc_s.so -> ../../../aarch64-linux-gnu/libgcc_s.so.1
                    └── libstdc++.so -> ../../../aarch64-linux-gnu/libstdc++.so.6

Host(Linux x86_64)#

Clang installation#

Clang and LLVM#

git clone --branch=llvmorg-11.1.0 --depth=1 \
    https://github.com/llvm/llvm-project.git $HOME/flutter-engine/llvm-project

cd $HOME/flutter-engine/llvm-project

ARM
ARM64

[ -d build_llvm ] && sudo rm -r build_llvm ;\
cmake -G Ninja \
    -S llvm \
    -B build_llvm \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_CROSSCOMPILING=True \
    -DCMAKE_INSTALL_PREFIX=$HOME/flutter-engine/sdk/toolchain \
    -DLLVM_ENABLE_PROJECTS=clang \
    -DLLVM_DEFAULT_TARGET_TRIPLE=aarch64-linux-gnu \
    -DLLVM_TARGET_ARCH=AArch64 \
    -DLLVM_TARGETS_TO_BUILD=AArch64

cmake --build build_llvm \
&& sudo cmake --install build_llvm

binutils-gdb#

git clone --depth=1 git://sourceware.org/git/binutils-gdb.git \
    $HOME/flutter-engine/binutils-gdb

cd $HOME/flutter-engine/binutils-gdb

ARM
ARM64

./configure --prefix="$HOME/flutter-engine/sdk/toolchain" \
    --enable-gold \
    --enable-ld \
    --target=aarch64-linux-gnu

make -j$(expr $(expr $(nproc) \* 6) \/ 5) \
&& sudo make install

libcxxabi and libcxx#

libcxx is statically linked to the engine for minimal dependencies.

cd $HOME/flutter-engine/llvm-project

ARM
ARM64

[ -d build_libcxxabi ] && sudo rm -r build_libcxxabi ;\
cmake -G Ninja \
    -S libcxxabi \
    -B build_libcxxabi \
    -DCMAKE_MAKE_PROGRAM=$(which ninja) \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_SYSROOT=$HOME/flutter-engine/sdk/sysroot \
    -DCMAKE_INSTALL_PREFIX=$HOME/flutter-engine/sdk/toolchain \
    -DCMAKE_SYSTEM_NAME=Linux \
    -DCMAKE_SYSTEM_PROCESSOR=AArch64 \
    -DCMAKE_C_COMPILER=$HOME/flutter-engine/sdk/toolchain/bin/clang \
    -DCMAKE_CXX_COMPILER=$HOME/flutter-engine/sdk/toolchain/bin/clang++ \
    -DCMAKE_AR=$HOME/flutter-engine/sdk/toolchain/bin/aarch64-linux-gnu-ar \
    -DCMAKE_RANLIB=$HOME/flutter-engine/sdk/toolchain/bin/aarch64-linux-gnu-ranlib \
    -DLLVM_TARGETS_TO_BUILD=AArch64 \
    -DLIBCXX_ENABLE_SHARED=False \
    -DLIBCXXABI_ENABLE_EXCEPTIONS=False

cmake --build build_libcxxabi \
&& sudo cmake --install build_libcxxabi

ARM
ARM64

[ -d build_libcxx ] && sudo rm -r build_libcxx ;\
cmake -G Ninja \
    -S libcxx \
    -B build_libcxx \
    -DCMAKE_MAKE_PROGRAM=$(which ninja) \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_SYSROOT=$HOME/flutter-engine/sdk/sysroot \
    -DCMAKE_INSTALL_PREFIX=$HOME/flutter-engine/sdk/toolchain \
    -DCMAKE_SYSTEM_NAME=Linux \
    -DCMAKE_SYSTEM_PROCESSOR=AArch64 \
    -DCMAKE_C_COMPILER=$HOME/flutter-engine/sdk/toolchain/bin/clang \
    -DCMAKE_CXX_COMPILER=$HOME/flutter-engine/sdk/toolchain/bin/clang++ \
    -DCMAKE_AR=$HOME/flutter-engine/sdk/toolchain/bin/aarch64-linux-gnu-ar \
    -DCMAKE_RANLIB=$HOME/flutter-engine/sdk/toolchain/bin/aarch64-linux-gnu-ranlib \
    -DLLVM_TARGETS_TO_BUILD=AArch64 \
    -DLIBCXX_ENABLE_EXCEPTIONS=False \
    -DLIBCXX_ENABLE_SHARED=False \
    -DLIBCXX_ENABLE_RTTI=False \
    -DLIBCXX_CXX_ABI=libcxxabi \
    -DLIBCXX_CXX_ABI_INCLUDE_PATHS=$HOME/flutter-engine/llvm-project/libcxxabi/include \
    -DLIBCXX_CXX_ABI_LIBRARY_PATH=$HOME/flutter-engine/sdk/toolchain/lib \
    -DLIBCXX_ENABLE_STATIC_ABI_LIBRARY=True

cmake --build build_libcxx \
&& sudo cmake --install build_libcxx

depot_tools#

git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git \
    $HOME/flutter-engine/depot_tools

export PATH=$PATH:$HOME/flutter-engine/depot_tools

flutter-engine#

Ref: https://github.com/flutter/flutter/wiki/Setting-up-the-Engine-development-environment

info

After reading the Ref above, follow flutter-engine part.

echo 'solutions = [
  {
    "managed": False,
    "name": "src/flutter",
    "url": "git@github.com:hhk7734/engine.git",
    "custom_deps": {},
    "deps_file": "DEPS",
    "safesync_url": "",
  },
]' >> $HOME/flutter-engine/engine/.gclient \
&& cd $HOME/flutter-engine/engine \
&& gclient sync -D

Select engine revision#

cd $HOME/flutter-engine/engine/src/flutter \
&& git remote add upstream git@github.com:flutter/engine.git

git checkout master \
&& git pull upstream master \
&& git push origin master

git checkout <engine revision>

gclient sync -D

Dependencies#

cd $HOME/flutter-engine/engine/src \
&& sudo ./build/install-build-deps-android.sh

sudo ./build/install-build-deps.sh

sudo ./flutter/build/install-build-deps-linux-desktop.sh

Build#

cd $HOME/flutter-engine/engine/src

ARM
ARM64

cp $HOME/flutter-engine/sdk/sysroot/usr/lib/aarch64-linux-gnu/pkgconfig/* \
    $HOME/flutter-engine/sdk/sysroot/usr/share/pkgconfig

[ -d out/linux_debug_arm64 ] && sudo rm -r out/linux_debug_arm64 ;\
./flutter/tools/gn \
    --target-sysroot $HOME/flutter-engine/sdk/sysroot \
    --target-toolchain $HOME/flutter-engine/sdk/toolchain \
    --target-triple aarch64-linux-gnu \
    --target-os linux \
    --linux-cpu arm64 \
    --embedder-for-target \
    --no-lto \
    --no-goma \
    --runtime-mode debug

ninja -C out/linux_debug_arm64

[ -d out/linux_profile_arm64 ] && sudo rm -r out/linux_profile_arm64 ;\
./flutter/tools/gn \
    --target-sysroot $HOME/flutter-engine/sdk/sysroot \
    --target-toolchain $HOME/flutter-engine/sdk/toolchain \
    --target-triple aarch64-linux-gnu \
    --target-os linux \
    --linux-cpu arm64 \
    --embedder-for-target \
    --no-lto \
    --no-goma \
    --runtime-mode profile

ninja -C out/linux_profile_arm64

[ -d out/linux_release_arm64 ] && sudo rm -r out/linux_release_arm64 ;\
./flutter/tools/gn \
    --target-sysroot $HOME/flutter-engine/sdk/sysroot \
    --target-toolchain $HOME/flutter-engine/sdk/toolchain \
    --target-triple aarch64-linux-gnu \
    --target-os linux \
    --linux-cpu arm64 \
    --embedder-for-target \
    --no-lto \
    --no-goma \
    --runtime-mode release

ninja -C out/linux_release_arm64