aarch64-linux-gnu cross-compilation

Allows one to easily cross-compile for aarch64 on a Debian/Ubuntu host.
Also adds a GitHub Action for it.

.github/workflows/Linux_aarch64.yml

@@ -0,0 +1,79 @@
+name: Linux AArch64
+
+on:
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - '*.md'
+  pull_request:
+    types: [opened, synchronize]
+    paths-ignore:
+      - '*.md'
+  release:
+    types: [published]
+    paths-ignore:
+      - '*.md'
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-20.04
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+
+    - name: Create Build Environment
+      run: |
+        # Work around the somewhat broken packages in the GitHub Actions Ubuntu 20.04 image.
+        # https://github.com/actions/runner-images/issues/4620#issuecomment-981333260
+        sudo apt-get -y install --allow-downgrades libpcre2-8-0=10.34-7
+        Packaging/nix/debian-cross-aarch64-prep.sh
+
+    - name: Build
+      working-directory: ${{github.workspace}}
+      shell: bash
+      env:
+        CMAKE_BUILD_TYPE: ${{github.event_name == 'release' && 'Release' || 'RelWithDebInfo'}}
+      # We set DEVILUTIONX_SYSTEM_LIBFMT=OFF because its soversion changes frequently.
+      run: |
+        cmake -S. -Bbuild -DCMAKE_TOOLCHAIN_FILE=../CMake/platforms/aarch64-linux-gnu.toolchain.cmake \
+          -DCMAKE_BUILD_TYPE=${{env.CMAKE_BUILD_TYPE}} -DCMAKE_INSTALL_PREFIX=/usr -DCPACK=ON \
+          -DDEVILUTIONX_SYSTEM_LIBFMT=OFF && \
+        cmake --build build -j $(getconf _NPROCESSORS_ONLN) --target package
+
+    - name: Package
+      run: Packaging/nix/LinuxReleasePackaging.sh && mv devilutionx.tar.xz devilutionx-aarch64.tar.xz
+
+    # AppImage cross-packaging is not implemented yet.
+    # - name: Package AppImage
+    #   run: Packaging/nix/AppImage.sh && mv devilutionx.appimage devilutionx-aarch64.appimage
+
+    - name: Upload Package
+      if: ${{ !env.ACT }}
+      uses: actions/upload-artifact@v2
+      with:
+        name: devilutionx-aarch64.tar.xz
+        path: devilutionx-aarch64.tar.xz
+
+    # AppImage cross-packaging is not implemented yet.
+    # - name: Upload AppImage
+    #   if: ${{ !env.ACT }}
+    #   uses: actions/upload-artifact@v2
+    #   with:
+    #     name: devilutionx-aarch64.appimage
+    #     path: devilutionx-aarch64.appimage
+
+    - name: Update Release
+      if: ${{ github.event_name == 'release' && !env.ACT }}
+      uses: svenstaro/upload-release-action@v2
+      with:
+        file: devilutionx-aarch64.*
+        file_glob: true
+        overwrite: true

.gitignore

@@ -22,6 +22,9 @@ comparer-config.toml
 # Extra files in the source distribution (see make_src_dist.py)
 /dist/
 
+*.appimage
+*.AppImage
+
 # ELF object file, shared library and object archive.
 *.o
 *.so

CMake/platforms/aarch64-linux-gnu-pkg-config

@@ -0,0 +1 @@
+debian-cross-pkg-config.sh

CMake/platforms/aarch64-linux-gnu.toolchain.cmake

@@ -0,0 +1,18 @@
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR aarch64)
+
+set(CMAKE_C_COMPILER "/usr/bin/aarch64-linux-gnu-gcc")
+set(CMAKE_CXX_COMPILER "/usr/bin/aarch64-linux-gnu-g++")
+
+set(CMAKE_FIND_ROOT_PATH "/usr/aarch64-linux-gnu;/usr")
+set(CMAKE_LIBRARY_ARCHITECTURE aarch64-linux-gnu)
+
+set(PKG_CONFIG_EXECUTABLE "${CMAKE_CURRENT_LIST_DIR}/aarch64-linux-gnu-pkg-config" CACHE STRING "Path to pkg-config")
+
+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(CPACK_DEBIAN_PACKAGE_ARCHITECTURE arm64)

CMake/platforms/debian-cross-pkg-config.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+# pkg-config wrapper for cross-building
+# Sets pkg-config search path to search multiarch and historical cross-compiling paths.
+
+# https://gist.github.com/doug65536/ea9c52f9a65a655a2fd5cc4997e8443b
+
+# If the user has already set PKG_CONFIG_LIBDIR, believe it (even if empty):
+# it's documented to be an override
+if [ x"${PKG_CONFIG_LIBDIR+set}" = x ]; then
+  # GNU triplet for the compiler, e.g. i486-linux-gnu for Debian i386,
+  # i686-linux-gnu for Ubuntu i386
+  basename="`basename "$0"`"
+  triplet="${basename%-pkg-config}"
+  # Normalized multiarch path if any, e.g. i386-linux-gnu for i386
+  multiarch="`dpkg-architecture -t"${triplet}" -qDEB_HOST_MULTIARCH 2>/dev/null`"
+  # Native multiarch path
+  native_multiarch="$(cat /usr/lib/pkg-config.multiarch)"
+
+  # This can be used for native builds as well, in that case, just exec pkg-config "$@" directly.
+  if [ "$native_multiarch" = "$multiarch" ]; then
+     exec pkg-config "$@"
+  fi
+
+  PKG_CONFIG_LIBDIR="/usr/local/${triplet}/lib/pkgconfig"
+  # For a native build we would also want to append /usr/local/lib/pkgconfig
+  # at this point; but this is a cross-building script, so don't
+  PKG_CONFIG_LIBDIR="$PKG_CONFIG_LIBDIR:/usr/local/share/pkgconfig"
+
+  if [ -n "$multiarch" ]; then
+    PKG_CONFIG_LIBDIR="/usr/local/lib/${multiarch}/pkgconfig:$PKG_CONFIG_LIBDIR"
+    PKG_CONFIG_LIBDIR="$PKG_CONFIG_LIBDIR:/usr/lib/${multiarch}/pkgconfig"
+  fi
+
+  PKG_CONFIG_LIBDIR="$PKG_CONFIG_LIBDIR:/usr/${triplet}/lib/pkgconfig"
+  # For a native build we would also want to append /usr/lib/pkgconfig
+  # at this point; but this is a cross-building script, so don't
+  # If you want to allow use of un-multiarched -dev packages for crossing
+  # (at the risk of finding build-arch stuff you didn't want, if not in a clean chroot)
+  # Uncomment the next line:
+  # PKG_CONFIG_LIBDIR="$PKG_CONFIG_LIBDIR:/usr/lib/pkgconfig"
+  # ... but on Ubuntu we rely cross-building with non-multiarch libraries:
+  if dpkg-vendor --derives-from Ubuntu; then
+      PKG_CONFIG_LIBDIR="$PKG_CONFIG_LIBDIR:/usr/lib/pkgconfig"
+  fi
+  PKG_CONFIG_LIBDIR="$PKG_CONFIG_LIBDIR:/usr/share/pkgconfig"
+
+  export PKG_CONFIG_LIBDIR
+fi
+
+exec pkg-config "$@"

Packaging/nix/AppImage.sh

@@ -1,6 +1,19 @@
-make install -Cbuild DESTDIR=AppDir
-mv build/AppDir/usr/share/diasurgical/devilutionx/devilutionx.mpq build/AppDir/usr/bin/devilutionx.mpq
-wget https://github.com/linuxdeploy/linuxdeploy/releases/download/continuous/linuxdeploy-x86_64.AppImage -N
-chmod +x linuxdeploy-x86_64.AppImage
-./linuxdeploy-x86_64.AppImage --appimage-extract-and-run --appdir=build/AppDir --custom-apprun=Packaging/nix/AppRun -d Packaging/nix/devilutionx.desktop -o appimage
+#!/usr/bin/env bash
+set -euo pipefail
+set -x
+
+BUILD_DIR="${1-build}"
+cmake --install "$BUILD_DIR" --prefix "${BUILD_DIR}/AppDir/usr"
+mv "$BUILD_DIR"/AppDir/usr/share/diasurgical/devilutionx/devilutionx.mpq "$BUILD_DIR"/AppDir/usr/bin/devilutionx.mpq
+
+APPIMAGE_BUILDER="${APPIMAGE_BUILDER:-linuxdeploy-x86_64.AppImage}"
+if ! which "$APPIMAGE_BUILDER"; then
+	if ! [[ -f linuxdeploy-x86_64.AppImage ]]; then
+		wget -q https://github.com/linuxdeploy/linuxdeploy/releases/download/continuous/linuxdeploy-x86_64.AppImage -N
+		chmod +x linuxdeploy-x86_64.AppImage
+	fi
+	APPIMAGE_BUILDER=./linuxdeploy-x86_64.AppImage
+fi
+"$APPIMAGE_BUILDER" --appimage-extract-and-run --appdir="$BUILD_DIR"/AppDir --custom-apprun=Packaging/nix/AppRun -d Packaging/nix/devilutionx.desktop -o appimage
+
 mv DevilutionX*.AppImage devilutionx.appimage

Packaging/nix/debian-cross-aarch64-prep.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+set -euo pipefail
+set -x
+
+FLAVOR="$(lsb_release -sc)"
+
+if dpkg-vendor --derives-from Ubuntu; then
+	sudo tee /etc/apt/sources.list.d/arm64.list <<LIST
+deb [arch=arm64] http://ports.ubuntu.com/ ${FLAVOR} main restricted
+deb [arch=arm64] http://ports.ubuntu.com/ ${FLAVOR}-updates main restricted
+deb [arch=arm64] http://ports.ubuntu.com/ ${FLAVOR} universe
+deb [arch=arm64] http://ports.ubuntu.com/ ${FLAVOR}-updates universe
+deb [arch=arm64] http://ports.ubuntu.com/ ${FLAVOR} multiverse
+deb [arch=arm64] http://ports.ubuntu.com/ ${FLAVOR}-updates multiverse
+deb [arch=arm64] http://ports.ubuntu.com/ ${FLAVOR}-backports main restricted universe multiverse
+LIST
+	sudo sed -i 's/deb http/deb [arch=amd64,i386] http/' /etc/apt/sources.list
+fi
+
+sudo dpkg --add-architecture arm64
+sudo apt-get update
+sudo apt-get install -y cmake git smpq gettext crossbuild-essential-arm64 \
+  libsdl2-dev:arm64 libsdl2-image-dev:arm64 libsodium-dev:arm64 \
+  libsimpleini-dev:arm64 libpng-dev:arm64 libbz2-dev:arm64 libfmt-dev:arm64

README.md

@@ -49,6 +49,7 @@ If you want to help test the latest development stage of the next version (make
 
 [![Linux x86](https://github.com/diasurgical/devilutionX/actions/workflows/Linux_x86.yml/badge.svg)](https://github.com/diasurgical/devilutionX/actions/workflows/Linux_x86.yml?query=branch%3Amaster)
 [![Linux x86-64 SDL1](https://github.com/diasurgical/devilutionX/actions/workflows/Linux_x86_64_SDL1.yml/badge.svg)](https://github.com/diasurgical/devilutionX/actions/workflows/Linux_x86_64_SDL1.yml?query=branch%3Amaster)
+[![Linux aarch64](https://github.com/diasurgical/devilutionX/actions/workflows/Linux_aarch64.yml/badge.svg)](https://github.com/diasurgical/devilutionX/actions/workflows/Linux_aarch64.yml?query=branch%3Amaster)
 [![MacOSX](https://github.com/diasurgical/devilutionX/actions/workflows/MacOSX.yml/badge.svg)](https://github.com/diasurgical/devilutionX/actions/workflows/MacOSX.yml?query=branch%3Amaster)
 [![Windows x64](https://github.com/diasurgical/devilutionX/actions/workflows/Windows_MSVC_x64.yml/badge.svg)](https://github.com/diasurgical/devilutionX/actions/workflows/Windows_MSVC_x64.yml?query=branch%3Amaster)
 [![Windows MinGW x64](https://github.com/diasurgical/devilutionX/actions/workflows/Windows_MinGW_x64.yml/badge.svg)](https://github.com/diasurgical/devilutionX/actions/workflows/Windows_MinGW_x64.yml?query=branch%3Amaster)

docs/building.md

@@ -46,6 +46,24 @@ cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release
 cmake --build build -j $(getconf _NPROCESSORS_ONLN)
 ```
 
+### Cross-compiling for arm64 (aarch64) on Debian or Ubuntu
+
+First, set up the dependencies for cross-compilation:
+
+```bash
+Packaging/nix/debian-cross-aarch64-prep.sh
+```
+
+Then, build DevilutionX using the cross-compilation CMake toolchain file:
+
+```bash
+cmake -S. -Bbuild-aarch64-rel \
+  -DCMAKE_TOOLCHAIN_FILE=../CMake/platforms/aarch64-linux-gnu.toolchain.cmake \
+  -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr -DCPACK=ON \
+  -DDEVILUTIONX_SYSTEM_LIBFMT=OFF
+cmake --build build-aarch64-rel -j $(getconf _NPROCESSORS_ONLN) --target package
+```
+
 </details>
 
 <details><summary>macOS</summary>