Difference between revisions of "Build D for Android"

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(Use environment variables to make the instructions more cross-platform)
 
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These instructions show you how to build D command-line executables and OpenGL ES GUI apps for Android, either by using [https://github.com/ldc-developers/ldc/releases the desktop D compilers for Windows, Mac, or linux available here] or a native Android compiler.  There are separate steps for cross-compilation, ie building apps on a Windows/linux PC or Mac and running the app on Android, versus native compilation, both building and running on your Android device itself.
+
These instructions show you how to build D command-line executables and OpenGL ES GUI apps for Android, either by using [https://github.com/ldc-developers/ldc/releases the desktop D compilers for Windows, Mac, or Linux available here] or a native Android compiler.  There are separate steps for cross-compilation, ie building apps on a Windows/Linux PC or Mac and running the app on Android, versus native compilation, both building and running on your Android device itself.
  
 
Since you cannot install the Android SDK on Android, I end by showing how to package a GUI Android app, a zip file called an .apk, from scratch, by using the tools available in the Termux app for Android, a terminal emulator app and open-source package manager/repository for Android devices.
 
Since you cannot install the Android SDK on Android, I end by showing how to package a GUI Android app, a zip file called an .apk, from scratch, by using the tools available in the Termux app for Android, a terminal emulator app and open-source package manager/repository for Android devices.
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==Prerequisites==
 
==Prerequisites==
 
===Cross-compilation===
 
===Cross-compilation===
* A command shell on your host PC/Mac, where you'll run the ldc D compiler
+
* A command shell on your host PC/Mac, where you'll run the LDC D compiler
 
** Either a DOS command prompt or Powershell should work on Windows.
 
** Either a DOS command prompt or Powershell should work on Windows.
** Any shell should work on Mac and linux, typical commands for the bash shell are shown.
+
** Any shell should work on Mac and Linux, typical commands for the <tt>bash</tt> shell are shown.
* Android native toolchain, [https://developer.android.com/ndk/index.html the NDK] and optionally [https://developer.android.com/studio/index.html the SDK]
+
* A recent version of the Android [https://developer.android.com/ndk/ NDK] and optionally the [https://developer.android.com/studio SDK]
 
** The SDK is necessary to package a GUI app; the NDK is enough if you just want to build a command-line binary.
 
** The SDK is necessary to package a GUI app; the NDK is enough if you just want to build a command-line binary.
* The ldc D compiler, either 1.4 or later, which has built-in cross-compilation support
+
* A recent LDC compiler for your host platform
* Common build tools
+
** It's best to use an [https://github.com/ldc-developers/ldc/releases official release from GitHub], as it's built against a [https://github.com/ldc-developers/llvm-project/releases slightly tweaked LLVM] with custom TLS emulation for Android targetsIf using LDC from your distro or elsewhere, make sure it was built against our tweaked LLVM, otherwise it will not compile properly for Android.
** <tt>CMake</tt> and either <tt>Make</tt> or <tt>Ninja</tt> are required to build the D runtime libraries for Android.  There are instructions below on setting these tools up for Windows, Mac, and linux.
 
 
* Android, whether a device or emulator, to run your D code
 
* Android, whether a device or emulator, to run your D code
 
** The SDK comes with an emulator.  I use actual hardware, so that's what I'll discuss.
 
** The SDK comes with an emulator.  I use actual hardware, so that's what I'll discuss.
** If using a device, you need some way to transfer the app over.  There are several ways to do this, here are a few I've tried:
+
** When using a device, you need some way to transfer the app over.  There are several ways to do this, here are a few I've tried:
 
# Install an ssh server app on your Android device and scp the app over.  Alternately, set up an ssh server on your host PC/Mac, and use an ssh/scp client on Android to get the app.  This is what I do, by using the OpenSSH package in Termux.  
 
# Install an ssh server app on your Android device and scp the app over.  Alternately, set up an ssh server on your host PC/Mac, and use an ssh/scp client on Android to get the app.  This is what I do, by using the OpenSSH package in Termux.  
 
# Host the app in a web server and get it by using your Android browser or a downloader app.
 
# Host the app in a web server and get it by using your Android browser or a downloader app.
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===Native compilation===
 
===Native compilation===
 +
* Android Version 10 ("Q"), as LDC compiler support does not exist for Android Version 9 ("Pie") and earlier.
 
* Termux for Android, available in [https://play.google.com/store/apps/details?id=com.termux&hl=en the official Play Store], [https://www.apkmirror.com/apk/fredrik-fornwall/termux/ APKMirror], or [https://f-droid.org/packages/com.termux/ F-Droid]
 
* Termux for Android, available in [https://play.google.com/store/apps/details?id=com.termux&hl=en the official Play Store], [https://www.apkmirror.com/apk/fredrik-fornwall/termux/ APKMirror], or [https://f-droid.org/packages/com.termux/ F-Droid]
 +
* LDC for Termux: <code>apt install ldc</code>  With Android version 9 and earlier, the install will fail.
  
==Setup==
+
==Cross-compilation setup==
  
Once you're at a command prompt or have the Termux app installed, get the ldc compiler for your OS and the NDK for cross-compilation, set some needed environment variables, and generate the runtime libraries for Android.
+
Once you have LDC and have unzipped the Android NDK, it's time to set up LDC for the desired Android target(s). See [[Cross-compiling with LDC]] for the general guide; I present two examples for a quick summary:
  
===Cross-compilation===
+
* Targeting 32-bit Android/ARMv7-A on a Win64 host:
====Windows====
+
*# Download the prebuilt <tt>android-armv7a</tt> [https://github.com/ldc-developers/ldc/releases/ package from GitHub] matching the version of your LDC.
 +
*# Extract the <tt>lib</tt> directory into your LDC installation directory and rename it, e.g., to <tt>lib-android_armv7a</tt>.
 +
*# Open <tt><LDC install dir>\etc\ldc2.conf</tt> in a text editor and append a section like this, adapting lib and NDK paths as needed:
 +
<pre>
 +
"armv7a-.*-linux-android":
 +
{
 +
    switches = [
 +
        "-defaultlib=phobos2-ldc,druntime-ldc",
 +
        "-link-defaultlib-shared=false",
 +
        "-gcc=C:/LDC/android-ndk-r21d/toolchains/llvm/prebuilt/windows-x86_64/bin/armv7a-linux-androideabi21-clang.cmd",
 +
    ];
 +
    lib-dirs = [
 +
        "%%ldcbinarypath%%/../lib-android_armv7a",
 +
    ];
 +
    rpath = "";
 +
};
 +
</pre>
 +
* Targeting 64-bit Android/AArch64 on a Linux host:
 +
*# Download the prebuilt <tt>android-aarch64</tt> [https://github.com/ldc-developers/ldc/releases/ package from GitHub] matching the version of your LDC.
 +
*# Extract the <tt>lib</tt> directory into your LDC installation directory and rename it, e.g., to <tt>lib-android_aarch64</tt>.
 +
*# Open <tt><LDC install dir>/etc/ldc2.conf</tt> in a text editor and append a section like this, adapting lib and NDK paths as needed:
 +
<pre>
 +
"aarch64-.*-linux-android":
 +
{
 +
    switches = [
 +
        "-defaultlib=phobos2-ldc,druntime-ldc",
 +
        "-link-defaultlib-shared=false",
 +
        "-gcc=/home/me/android-ndk-r21d/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android21-clang",
 +
    ];
 +
    lib-dirs = [
 +
        "%%ldcbinarypath%%/../lib-android_aarch64",
 +
    ];
 +
    rpath = "";
 +
};
 +
</pre>
  
Download [https://cmake.org/download/ CMake] and the zip files for [https://developer.android.com/ndk/downloads/ one of the Android NDKs for Windows], [https://github.com/ldc-developers/ldc/releases the latest ldc], and either Make or [https://github.com/ninja-build/ninja/releases Ninja] (the following instructions assume Ninja).  You will need [https://www.7-zip.org/download.html 7-Zip to unpack recent ldc releases]. Make sure <tt>unzip</tt> is available to unpack the rest of the build tools, then add them to your path, set the path of the NDK and its C cross-compiler, and run <tt>ldc-build-runtime</tt>.  I show the commands for 64-bit Windows, should be similar for 32-bit, except the Ninja zip only comes with a 64-bit version.
+
The prebuilt Android packages also include the corresponding x86 simulator libraries, so 32/64-bit x86 Android simulator targets can be set up the same way.
  
<syntaxhighlight lang=powershell>
+
==Build a command-line executable==
cd droid  # assuming all the zip files have been placed in a folder called droid
 
 
 
unzip cmake-3.11.4-win64-x64.zip
 
7z x ldc2-1.11.0-windows-x64.7z
 
unzip android-ndk-r17b-windows-x86_64.zip
 
unzip ninja-win.zip
 
 
 
set PATH=%PATH%;C:\Users\you\droid\cmake-3.11.4-win64-x64\bin;C:\Users\you\droid\ldc2-1.11.0-windows-x64\bin;C:\Users\you\droid
 
 
 
ldc2 --version  # run this to check that ldc is in your path
 
 
 
set CC=C:\Users\you\droid\android-ndk-r17b\toolchains\llvm\prebuilt\windows-x86_64\bin\clang
 
 
 
ldc-build-runtime --ninja --targetPreset=Android-arm --dFlags="-w;-mcpu=cortex-a8" --buildDir=droid32
 
 
 
ldc-build-runtime --ninja --targetPreset=Android-aarch64 --buildDir=droid64
 
 
 
set NDK=C:\Users\you\droid\android-ndk-r17b
 
</syntaxhighlight>
 
 
 
====Mac====
 
  
Download [https://cmake.org/download/ CMake], [https://developer.android.com/ndk/downloads/ the zip file for the Android NDK], [https://github.com/ldc-developers/ldc/releases the latest ldc], and either Make or [https://github.com/ninja-build/ninja/releases Ninja] (the following instructions assume Ninja).  CMake and Ninja can be installed from a package manager like [https://brew.sh Homebrew], but I'll show the manual install here.  Make sure <tt>unzip</tt> is available to unpack the NDK and <tt>tar</tt> for everything else. After unpacking, add these tools to your path, including setting the path of the NDK and its C cross-compiler, and run <tt>ldc-build-runtime</tt>.
+
Now that we have a D compiler setup for (one or more) Android targets, let's try building a small program, [https://github.com/dlang/dmd/blob/master/samples/sieve.d the classic Sieve of Eratosthenes single-core benchmark], which finds all prime numbers up to a number you choose. Install the curl package in Termux if you're natively compiling, <tt>apt install curl</tt>.
  
 
<syntaxhighlight lang=bash>
 
<syntaxhighlight lang=bash>
cd droid  # assuming all the zip and tar files have been placed in a folder called droid
+
# Load this link in your browser and download the file otherwise
 +
curl -L -O https://raw.githubusercontent.com/dlang/dmd/master/samples/sieve.d
  
tar xf cmake-3.11.4-Darwin-x86_64.tar.gz
+
# Cross-compile & -link to ARMv7-A (on any host)
tar xf ldc2-1.11.0-osx-x86_64.tar.xz
+
ldc2 -mtriple=armv7a--linux-androideabi sieve.d
unzip android-ndk-r17b-darwin-x86_64.zip
 
unzip ninja-mac.zip
 
  
export PATH=$PATH:/Users/you/droid/cmake-3.11.4-Darwin-x86_64/CMake.app/Contents/bin:/Users/you/droid/ldc2-1.11.0-osx-x86_64/bin:/Users/you/droid
+
# Cross-compile & -link to AArch64 (on any host)
 +
ldc2 -mtriple=aarch64--linux-android sieve.d
  
ldc2 --version  # run this to check that ldc is in your path
+
# Compile & link natively in Termux
 
+
ldc2 sieve.d
export CC=/Users/you/droid/android-ndk-r17b/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang
 
 
 
ldc-build-runtime --ninja --targetPreset=Android-arm --dFlags="-w;-mcpu=cortex-a8" --buildDir=droid32
 
 
 
ldc-build-runtime --ninja --targetPreset=Android-aarch64 --buildDir=droid64
 
 
 
export NDK=/Users/you/droid/android-ndk-r17b
 
export HOST=darwin-x86_64
 
</syntaxhighlight>
 
 
 
====linux====
 
 
 
Install needed packages, including optionally Ninja, as shown here for Ubuntu.  You will need <tt>tar</tt> to unpack ldc and <tt>unzip</tt> for the NDK.  Add ldc to your path and export the path of the NDK and its C cross-compiler, as shown here for bash, and run <tt>ldc-build-runtime</tt>.
 
 
 
<syntaxhighlight lang=bash>
 
sudo apt-get install build-essential cmake curl ninja unzip
 
 
 
curl -L -O https://dl.google.com/android/repository/android-ndk-r17b-linux-x86_64.zip
 
 
 
unzip android-ndk-r17b-linux-x86_64.zip
 
 
 
curl -L -O https://github.com/ldc-developers/ldc/releases/download/v1.11.0/ldc2-1.11.0-linux-x86_64.tar.xz
 
 
 
tar xf ldc2-1.11.0-linux-x86_64.tar.xz
 
export PATH=$PATH:/path/to/your/ldc2-1.11.0-linux-x86_64/bin
 
 
 
ldc2 --version  # check that ldc is your path
 
 
 
export CC=/path/to/your/android-ndk-r17b/toolchains/llvm/prebuilt/linux-x86_64/bin/clang
 
 
 
ldc-build-runtime --targetPreset=Android-arm --dFlags="-w;-mcpu=cortex-a8" --buildDir=droid32
 
 
 
ldc-build-runtime --targetPreset=Android-aarch64 --buildDir=droid64
 
 
 
export NDK=/path/to/your/android-ndk-r17b
 
export HOST=linux-x86_64
 
 
</syntaxhighlight>
 
</syntaxhighlight>
 
====Set environment variables====
 
 
The environment variables vary based on whether you want to target 32-bit or 64-bit ARM.
 
 
=====32-bit ARM=====
 
 
On linux or macOS:
 
<syntaxhighlight lang=bash>
 
export TRIPLE=armv7-none-linux-androideabi
 
export DFLAGS="-mtriple=$TRIPLE -mcpu=cortex-a8"
 
export LIBDIR=droid32
 
 
export NDK_ARCH=arch-arm
 
export NDK_LINKER=arm-linux-androideabi-4.9
 
export APK_DIR=armeabi-v7a
 
</syntaxhighlight>
 
 
On Windows:
 
<syntaxhighlight lang=powershell>
 
set TRIPLE=armv7-none-linux-androideabi
 
set DFLAGS=-mtriple=%TRIPLE% -mcpu=cortex-a8
 
set LIBDIR=droid32
 
 
set NDK_ARCH=arch-arm
 
set NDK_LINKER=arm-linux-androideabi-4.9
 
set APK_DIR=armeabi-v7a
 
</syntaxhighlight>
 
 
=====64-bit ARM=====
 
 
On linux/macOS:
 
<syntaxhighlight lang=bash>
 
export TRIPLE=aarch64-none-linux-android
 
export DFLAGS="-mtriple=$TRIPLE"
 
export LIBDIR=droid64
 
 
export NDK_ARCH=arch-arm64
 
export NDK_LINKER=aarch64-linux-android-4.9
 
export APK_DIR=arm64-v8a
 
</syntaxhighlight>
 
 
On Windows:
 
<syntaxhighlight lang=powershell>
 
set TRIPLE=aarch64-none-linux-android
 
set DFLAGS=-mtriple=%TRIPLE%
 
set LIBDIR=droid64
 
 
set NDK_ARCH=arch-arm64
 
set NDK_LINKER=aarch64-linux-android-4.9
 
set APK_DIR=arm64-v8a
 
</syntaxhighlight>
 
 
===== Set path to runtime =====
 
 
Finally, set the path to the runtime libraries you just built:
 
 
<syntaxhighlight lang=bash>
 
# On linux
 
export RTDIR=/path/to/your/$LIBDIR
 
 
# On Mac
 
export RTDIR=/Users/you/droid/$LIBDIR
 
 
# On Windows
 
set RTDIR=C:\Users\you\droid\%LIBDIR%
 
</syntaxhighlight>
 
 
===Native compilation===
 
 
Just install ldc from the Termux app, which will automatically pull in the clang compiler and a linker, as ldc tries to use the local C compiler for linking.
 
<syntaxhighlight lang=bash>
 
apt install ldc
 
</syntaxhighlight>
 
 
==Build a command-line executable==
 
 
Now that we have a D compiler and runtime libraries for Android, let's try building a small program, [https://github.com/dlang/dmd/blob/master/samples/sieve.d the classic Sieve of Eratosthenes single-core benchmark], which finds all prime numbers up to a number you choose.
 
  
 
===Cross-compilation===
 
===Cross-compilation===
 
<syntaxhighlight lang=bash>
 
# Load this link in your browser and download the file otherwise
 
curl -L -O
 
https://raw.githubusercontent.com/dlang/dmd/master/samples/sieve.d
 
 
# On linux/macOS
 
ldc2 -L-L$RTDIR/lib
 
-Xcc=--sysroot=$NDK/platforms/android-21/$NDK_ARCH -Xcc=-fuse-ld=bfd -Xcc=-gcc-toolchain
 
-Xcc=$NDK/toolchains/$NDK_LINKER/prebuilt/$HOST -Xcc=-target
 
-Xcc=$TRIPLE -Xcc=-fpie -Xcc=-pie sieve.d
 
 
# On 64-bit Windows
 
ldc2 -L-L%RTDIR%\lib
 
-Xcc=--sysroot=%NDK%\platforms\android-21\%NDK_ARCH%
 
-Xcc=-fuse-ld=bfd.exe -Xcc=-gcc-toolchain
 
-Xcc=%NDK%\toolchains\%NDK_LINKER%\prebuilt\windows-x86_64 -Xcc=-target
 
-Xcc=%TRIPLE% -Xcc=-fpie -Xcc=-pie sieve.d
 
</syntaxhighlight>
 
  
 
Copy this <tt>sieve</tt> program onto an Android device or emulator and set its permissions with the <tt>chmod</tt> command. Here's how I do it in Termux, with an ssh server running on the host PC/Mac with IP address 192.168.1.37:
 
Copy this <tt>sieve</tt> program onto an Android device or emulator and set its permissions with the <tt>chmod</tt> command. Here's how I do it in Termux, with an ssh server running on the host PC/Mac with IP address 192.168.1.37:
Line 213: Line 94:
 
scp jo@192.168.1.37:sieve .
 
scp jo@192.168.1.37:sieve .
 
chmod 700 sieve
 
chmod 700 sieve
</syntaxhighlight>
 
 
===Native compilation===
 
<syntaxhighlight lang=bash>
 
apt install curl
 
 
curl -L -O
 
https://raw.githubusercontent.com/dlang/dmd/master/samples/sieve.d
 
 
ldc2 sieve.d
 
 
</syntaxhighlight>
 
</syntaxhighlight>
  
Line 240: Line 111:
 
==Build a sample OpenGL ES 1.0 GUI app ported to D==
 
==Build a sample OpenGL ES 1.0 GUI app ported to D==
  
Clone [https://github.com/joakim-noah/android my android repository] or [https://github.com/joakim-noah/android/releases download its source in a zip file], which contains several headers and sample OpenGL apps from the NDK translated to D, and build the Native Activity app, which is written completely in D.  As you'll see below, D code for an apk must be compiled to a shared library, which the Android runtime will call.
+
Clone the [https://github.com/Diewi/android android repository] or download [https://github.com/Diewi/android/releases its source in a zip file], which contains several headers and sample OpenGL apps from the NDK translated to D:
 
 
===Cross-compilation===
 
 
 
On linux, you can just clone my git repo (the same can be done on Mac and Windows if you install <tt>git</tt> first):
 
  
 
<syntaxhighlight lang=bash>
 
<syntaxhighlight lang=bash>
sudo apt-get install git
+
sudo apt-get install git # In Termux, apt install git
 +
git clone https://github.com/Diewi/android.git
 +
cd android
  
git clone https://github.com/joakim-noah/android.git
+
# Alternatively, without git:
 
+
curl -L -O https://github.com/Diewi/android/archive/build.zip
cd android/
+
unzip build.zip
 +
cd android-build
 
</syntaxhighlight>
 
</syntaxhighlight>
  
Otherwise, simply get and unpack the zip file:
+
Then build the Native Activity app, which is written completely in D. D code for an apk must be compiled to a shared library, which the Android runtime will call:
  
 
<syntaxhighlight lang=bash>
 
<syntaxhighlight lang=bash>
curl -L -O https://github.com/joakim-noah/android/archive/build.zip
+
cd samples/native-activity
  
unzip build.zip
+
ldc2 -I../.. jni/main.d ../../android/sensor.d ../../android_native_app_glue.d \
cd android-build/
+
    -shared -of=libs/arm64-v8a/libnative-activity.so \ # or `libs/armeabi-v7a/...` for 32-bit ARM
 +
    -L-soname -Llibnative-activity.so \
 +
    -mtriple=aarch64--linux-android # only for cross-compilation; use `armv7a--linux-androideabi` for 32-bit ARM
 +
    # possibly needed: -L-llog -L-landroid -L-lEGL -L-lGLESv1_CM
 
</syntaxhighlight>
 
</syntaxhighlight>
  
After getting the source, go to the sample app, compile the D source, then link the objects into a shared library and place it in the directory that the SDK expects.
+
===Cross-compilation===
 +
 
 +
====Ant approach====
 +
Finally, package the app as the SDK directs: at this point, it's just like building a regular Android app.  I document the older Ant approach, which is deprecated, replace it with the Gradle command from a newer SDK.  With Ant on Mac or Linux, set the path to your SDK, then run these commands:
  
 
<syntaxhighlight lang=bash>
 
<syntaxhighlight lang=bash>
cd samples/native-activity/
+
export SDK=/path/to/your/android-sdk
 
+
$SDK/tools/android update project -p . -s --target 1
ldc2 -I../../ -c jni/main.d
+
ant debug
 +
</syntaxhighlight>
  
ldc2 -I../../ -c ../../android/sensor.d
+
====Android Studio approach====
  
ldc2 -I../../ -c ../../android_native_app_glue.d
+
Enter on your <application name>/app/src/main and create a folder called jniLibs, this folder is <b>extremely important</b>, it is the default folder to put your shared libraries to be imported together with your .apk. If you wish to use other name for it, you will need to change your gradle file. For actually putting your libraries inside that folder, you will actually need to make directories for the target architectures, so, create inside it:
  
mkdir -p libs/$APK_DIR/   # On Windows, mkdir libs\%APK_DIR%
+
* armeabi-v7a (For that, it is commonly used ldc2(version)-android-armv7a/lib
 +
* arm64-v8a (This is our target right now, ldc2(version)-android-aarch64/lib)
 +
* x86 (It is the lib32 for armv7a -> ldc2(version)-android-armv7a/lib686
 +
* x86_64 (It is the lib32 for the aarch64 -> ldc2(version)-android-aarch64/lib-x86_64 For reference, check ndk abi guide from official android site: [https://developer.android.com/ndk/guides/abis Android ABI Guide]
  
# On linux/macOS
+
After creating those folders, you can actually move your shared library inside one of them, just click on run and you're good to go.
$CC -Wl,-soname,libnative-activity.so -shared --sysroot=$NDK/platforms/android-21/$NDK_ARCH
 
main.o sensor.o android_native_app_glue.o $RTDIR/lib/libphobos2-ldc.a
 
$RTDIR/lib/libdruntime-ldc.a -gcc-toolchain
 
$NDK/toolchains/$NDK_LINKER/prebuilt/$HOST -fuse-ld=bfd -target $TRIPLE -llog -landroid -lEGL -lGLESv1_CM
 
-o libs/$APK_DIR/libnative-activity.so
 
  
# On 64-bit Windows
+
---
%CC% -Wl,-soname,libnative-activity.so -shared --sysroot=%NDK%\platforms\android-21\%NDK_ARCH%
 
main.o sensor.o android_native_app_glue.o %RTDIR%\lib\libphobos2-ldc.a
 
%RTDIR%\lib\libdruntime-ldc.a -gcc-toolchain
 
%NDK%\toolchains\%NDK_LINKER%\prebuilt\windows-x86_64 -fuse-ld=bfd.exe -target
 
%TRIPLE% -llog -landroid -lEGL -lGLESv1_CM
 
-o libs\%APK_DIR%\libnative-activity.so
 
</syntaxhighlight>
 
 
 
Finally, package the app as the SDK directs: at this point, it's just like building a regular Android app.  I document the older Ant approach, which is deprecated, replace it with the Gradle command from a newer SDK.  With Ant on Mac or linux, set the path to your SDK, then run these commands:
 
 
 
<syntaxhighlight lang=bash>
 
export SDK=/path/to/your/android-sdk
 
$SDK/tools/android update project -p . -s --target 1
 
ant debug
 
</syntaxhighlight>
 
  
 
Transfer the resulting <tt>bin/NativeActivity-debug.apk</tt> to your Android device, again shown here by using <tt>scp</tt> from the Termux app.
 
Transfer the resulting <tt>bin/NativeActivity-debug.apk</tt> to your Android device, again shown here by using <tt>scp</tt> from the Termux app.
Line 307: Line 167:
  
 
===Native compilation===
 
===Native compilation===
<syntaxhighlight lang=bash>
 
apt install git
 
 
git clone https://github.com/joakim-noah/android.git
 
 
cd android/samples/native-activity/
 
 
ldc2 -I../../ -c jni/main.d
 
 
ldc2 -I../../ -c ../../android/sensor.d
 
 
ldc2 -I../../ -c ../../android_native_app_glue.d
 
 
mkdir -p lib/armeabi-v7a/
 
 
$PREFIX/bin/clang -Wl,-soname,libnative-activity.so -shared main.o sensor.o
 
android_native_app_glue.o $PREFIX/lib/libphobos2-ldc.a $PREFIX/lib/libdruntime-ldc.a
 
-target armv7-none-linux-androideabi -llog -landroid -lEGL -lGLESv1_CM
 
-o lib/armeabi-v7a/libnative-activity.so
 
</syntaxhighlight>
 
  
 
[[#Package_an_Android_app_from_scratch_on_your_Android_device|Follow the instructions below to package this native shared library into an Android apk]].
 
[[#Package_an_Android_app_from_scratch_on_your_Android_device|Follow the instructions below to package this native shared library into an Android apk]].
Line 335: Line 175:
 
==Build a sample OpenGL ES 2.0 GUI app mostly written in D, with some Java==
 
==Build a sample OpenGL ES 2.0 GUI app mostly written in D, with some Java==
  
===Cross-compilation===
+
This D app has not been ported to 64-bit Android/ARM yet, only 32-bit ARM compilation will work for now:
This app comes with a simple build script, which will build the D shared library for you, as long as the environment variables are set.
 
  
 
<syntaxhighlight lang=bash>
 
<syntaxhighlight lang=bash>
cd samples/Teapot/
+
cd samples/Teapot
  
# On linux
+
ldc2 -I../.. -Ijni -Jjni \
./build-apk
+
    ../../ndk_helper/GLContext.d \
 +
    ../../ndk_helper/JNIHelper.d \
 +
    ../../ndk_helper/gestureDetector.d \
 +
    ../../ndk_helper/perfMonitor.d \
 +
    ../../ndk_helper/shader.d \
 +
    ../../ndk_helper/tapCamera.d \
 +
    jni/TeapotNativeActivity.d \
 +
    jni/TeapotRenderer.d \
 +
    ../../android/sensor.d \
 +
    ../../android_native_app_glue.d \
 +
    -shared -of=libs/armeabi-v7a/libTeapotNativeActivity.so \
 +
    -L-soname -LlibTeapotNativeActivity.so \
 +
    -mtriple=armv7a--linux-androideabi # only for cross-compilation
 +
    # possibly needed: -L-llog -L-landroid -L-lEGL -L-lGLESv2
 +
</syntaxhighlight>
  
# On Mac
+
===Cross-compilation===
./build-apk-mac
+
Package this shared library into an apk by using the SDK, as you would normally, and try installing and running it on your device.
  
# On 64-bit Windows
+
===Native compilation===
call build-apk.bat
 
</syntaxhighlight>
 
  
Here are the contents of that script, so you can see what it's doing.  The Windows version, <tt>build-apk.bat</tt>, and the Mac, <tt>build-apk-mac</tt>, only differ on the final link command, which I've pasted below.
+
Install the right Eclipse Java compiler package for your device (the ecj4.6 package if you're running Android 5 or 6), the Android dex tool, and other packages needed to build an Android apk. Generate any Java files needed, compile and dex them, then package everything up into an apk and sign it.
  
 
<syntaxhighlight lang=bash>
 
<syntaxhighlight lang=bash>
ldc2 -I../../ -c ../../ndk_helper/GLContext.d
+
apt install ecj dx aapt apksigner
ldc2 -I../../ -c ../../ndk_helper/JNIHelper.d
+
 
ldc2 -I../../ -c ../../ndk_helper/gestureDetector.d
+
aapt package  -M ./AndroidManifest.xml -I $PREFIX/share/java/android-21.jar -J src/ -S res -m
ldc2 -I../../ -c ../../ndk_helper/perfMonitor.d
+
 
ldc2 -I../../ -c ../../ndk_helper/shader.d
+
ecj-21 -d ./obj -sourcepath src $(find src -type f -name "*.java")
ldc2 -I../../ -c ../../ndk_helper/tapCamera.d
 
  
ldc2 -I../../ -Ijni/ -Jjni/ -c jni/TeapotNativeActivity.d
+
dx --dex --output=./classes.dex ./obj/
ldc2 -I../../ -Jjni/ -c jni/TeapotRenderer.d
 
ldc2 -I../../ -c ../../android/sensor.d
 
  
ldc2 -I../../ -c ../../android_native_app_glue.d
+
aapt package  -M ./AndroidManifest.xml -S res -A assets -F teapot.apk
  
# Link command on linux/macOS
+
aapt add teapot.apk classes.dex lib/armeabi-v7a/libTeapotNativeActivity.so
$CC -Wl,-soname,libTeapotNativeActivity.so -shared
 
--sysroot=$NDK/platforms/android-21/$NDK_ARCH TeapotNativeActivity.o sensor.o
 
TeapotRenderer.o android_native_app_glue.o GLContext.o JNIHelper.o
 
gestureDetector.o perfMonitor.o shader.o tapCamera.o
 
$RTDIR/lib/libphobos2-ldc.a $RTDIR/lib/libdruntime-ldc.a -gcc-toolchain
 
$NDK/toolchains/$NDK_LINKER/prebuilt/$HOST -fuse-ld=bfd
 
-target $TRIPLE -llog -landroid -lEGL -lGLESv2
 
-o libTeapotNativeActivity.so
 
  
# Link command on 64-bit Windows
+
apksigner debug.ks teapot.apk teapot-signed.apk
%CC% -Wl,-soname,libTeapotNativeActivity.so -shared
 
--sysroot=%NDK%\platforms\android-21\%NDK_ARCH% TeapotNativeActivity.o sensor.o
 
TeapotRenderer.o android_native_app_glue.o GLContext.o JNIHelper.o
 
gestureDetector.o perfMonitor.o shader.o tapCamera.o
 
%RTDIR%\lib\libphobos2-ldc.a %RTDIR%\lib\libdruntime-ldc.a -gcc-toolchain
 
%NDK%\toolchains\%NDK_LINKER%\prebuilt\windows-x86_64 -fuse-ld=bfd.exe
 
-target %TRIPLE% -llog -landroid -lEGL -lGLESv2
 
-o libTeapotNativeActivity.so
 
 
</syntaxhighlight>
 
</syntaxhighlight>
  
Package this shared library into an apk by using the SDK, as you would normally, and try installing and running it on your device.
+
Finally, move <tt>teapot-signed.apk</tt> into a public directory, from which you can install and run it.
 +
 
 +
==Examples and useful repositories==
 +
* [https://github.com/adamdruppe/d_android D Android from adamdruppe] - You can find android-setup.d which will download the pre-built Android runtimes for you and set up ldc2.conf;
 +
 
 +
* [https://github.com/MrcSnm/D-SDL-Android-Project D SDL Android from MrcSnm|Hipreme] - Provides an Android template project for working with [http://libsdl.org SDL2];
  
===Native compilation===
+
* [https://github.com/MrcSnm/D-Lang-on-Android D Lang on Android from MrcSnm|Hipreme] - Additional documentation about setting up a D project for [https://developer.android.com/studio Android Studio].
The steps are the same as above, except for a marginally different linker command, which is included in the <tt>build-apk</tt> script but commented out. However, this app requires compiling some Java code and the Java compilers in Termux aren't working at the moment, so I'll hold off on this for now.
 
  
 
==Changes for Android==
 
==Changes for Android==
Line 397: Line 233:
 
Now that you've seen some examples, here's a description of changes to D that have been made for Android.
 
Now that you've seen some examples, here's a description of changes to D that have been made for Android.
  
The Android environment doesn't support native Thread-Local Storage (TLS), which is integral to D, since [https://dlang.org/migrate-to-shared.html all static and global variables not explicitly marked shared/__gshared/immutable are thread-local by default in D].  The Android D runtime supports emulated TLS instead, but this requires some changes to the build process:
+
The Android environment doesn't support native Thread-Local Storage (TLS), which is integral to D, since [https://dlang.org/migrate-to-shared.html all static and global variables not explicitly marked shared/__gshared/immutable are thread-local by default in D].  The Android D runtime supports emulated TLS instead, but this currently requires the <tt>ld.bfd</tt> linker - <tt>ld.gold</tt> or <tt>lld</tt> won't do.
 
 
# You must use the <tt>ld.bfd</tt> linker- see the use of <tt>-fuse-ld=bfd</tt> above- <tt>ld.gold</tt> won't do.
 
# You must have a D <tt>main</tt> function, even for a shared library.  [https://github.com/joakim-noah/android/blob/940bd899664db1f72a68d83bff197d55952089be/samples/native-activity/jni/main.d#L227 An empty D <tt>main</tt> can be put next to <tt>android_main</tt>], if you're using the default Android wrapper from my D android repo.
 
# The ELF object with the D <tt>main</tt> function must be passed to the linker first.
 
 
 
All the examples above follow these rules, which are in place to make sure emulated TLS data is properly passed to the D garbage-collector.
 
  
If building a shared library and not a D command-line executable, you must also initialize and exit the D runtime by calling <tt>rt_init()</tt> and <tt>rt_term()</tt> before and after all D code is run, [https://github.com/joakim-noah/android/blob/4fbdbb1344725a593d8df1e008ba371c0e694a11/android_native_app_glue.d#L554 as has been done in the default Android wrapper] ([[Runtime internals|<tt>rt_init</tt>/<tt>rt_term</tt> are automatically inserted and run for a D executable]]).  Running multiple D shared libraries is currently unsupported on Android, only a single D shared library that statically links against the D runtime will work.
+
If building a shared library and not a D command-line executable, you must also initialize and exit the D runtime by calling <tt>rt_init()</tt> and <tt>rt_term()</tt> before and after all D code is run, [https://github.com/Diewi/android/blob/4fbdbb1344725a593d8df1e008ba371c0e694a11/android_native_app_glue.d#L554 as has been done in the default Android wrapper] ([[Runtime internals|<tt>rt_init</tt>/<tt>rt_term</tt> are automatically inserted and run for a D executable]]).  Running multiple D shared libraries is currently unsupported on Android, only a single D shared library that statically links against the D runtime will work.
  
 
==Package an Android app from scratch on your Android device==
 
==Package an Android app from scratch on your Android device==
Line 418: Line 248:
  
 
<syntaxhighlight lang=bash>
 
<syntaxhighlight lang=bash>
cd samples/native-activity/
+
cd samples/native-activity
 
aapt package -M AndroidManifest.xml -S res -F NativeActivity-debug-unsigned.apk
 
aapt package -M AndroidManifest.xml -S res -F NativeActivity-debug-unsigned.apk
aapt add NativeActivity-debug-unsigned.apk lib/armeabi-v7a/libnative-activity.so
+
APK_DIR=armeabi-v7a # or `arm64-v8a` for 64-bit ARM
 +
aapt add NativeActivity-debug-unsigned.apk libs/$APK_DIR/libnative-activity.so
 
</syntaxhighlight>
 
</syntaxhighlight>
  
This simple app only requires three files, <tt>AndroidManifest.xml</tt>, <tt>resources.arsc</tt>, and <tt>lib/armeabi-v7a/libnative-activity.so</tt>, which you can check with the following <tt>aapt</tt> command.
+
This simple app only requires three files, <tt>AndroidManifest.xml</tt>, <tt>resources.arsc</tt>, and <tt>libs/$APK_DIR/libnative-activity.so</tt>, which you can check with the following <tt>aapt</tt> command.
  
 
<syntaxhighlight lang=bash>
 
<syntaxhighlight lang=bash>
Line 489: Line 320:
 
The OpenSSL commands to generate a certificate and sign the apk were taken [http://qistoph.blogspot.com/2012/01/manual-verify-pkcs7-signed-data-with.html from this 2012 blog post], you can follow it further to see what the signature consists of and verify it for yourself.  [https://nelenkov.blogspot.com/2013/04/android-code-signing.html This 2013 blog post was critical for me to understand how apk signing works], I used to run all those commands by hand until the <tt>apksigner</tt> package was added to the Termux package repo.
 
The OpenSSL commands to generate a certificate and sign the apk were taken [http://qistoph.blogspot.com/2012/01/manual-verify-pkcs7-signed-data-with.html from this 2012 blog post], you can follow it further to see what the signature consists of and verify it for yourself.  [https://nelenkov.blogspot.com/2013/04/android-code-signing.html This 2013 blog post was critical for me to understand how apk signing works], I used to run all those commands by hand until the <tt>apksigner</tt> package was added to the Termux package repo.
  
[[Category: Android]]
+
==Directions for future work==
 +
 
 +
* Revise the way TLS data is initialized on Android. <tt>ld.bfd</tt> is required because it's the only linker putting the <tt>.tdata</tt> and <tt>.tbss</tt> sections adjacent to each other (by default).
 +
 
 +
* Integrate the linux shared library support in druntime's <tt>rt.sections_elf_shared</tt>, so that multiple D shared libraries can be used. Things may likely get complicated because of LDC's custom TLS emulation; using LLVM's default EmuTLS for Android instead might be an option.
 +
 
 +
* Fix [https://github.com/ldc-developers/ldc/issues/2153 the remaining stdlib incompatibilities on 64-bit ARM].
 +
 
 +
[[Category: Android]] [[Category: LDC]]

Latest revision as of 14:02, 28 August 2021

These instructions show you how to build D command-line executables and OpenGL ES GUI apps for Android, either by using the desktop D compilers for Windows, Mac, or Linux available here or a native Android compiler. There are separate steps for cross-compilation, ie building apps on a Windows/Linux PC or Mac and running the app on Android, versus native compilation, both building and running on your Android device itself.

Since you cannot install the Android SDK on Android, I end by showing how to package a GUI Android app, a zip file called an .apk, from scratch, by using the tools available in the Termux app for Android, a terminal emulator app and open-source package manager/repository for Android devices.

Prerequisites

Cross-compilation

  • A command shell on your host PC/Mac, where you'll run the LDC D compiler
    • Either a DOS command prompt or Powershell should work on Windows.
    • Any shell should work on Mac and Linux, typical commands for the bash shell are shown.
  • A recent version of the Android NDK and optionally the SDK
    • The SDK is necessary to package a GUI app; the NDK is enough if you just want to build a command-line binary.
  • A recent LDC compiler for your host platform
    • It's best to use an official release from GitHub, as it's built against a slightly tweaked LLVM with custom TLS emulation for Android targets. If using LDC from your distro or elsewhere, make sure it was built against our tweaked LLVM, otherwise it will not compile properly for Android.
  • Android, whether a device or emulator, to run your D code
    • The SDK comes with an emulator. I use actual hardware, so that's what I'll discuss.
    • When using a device, you need some way to transfer the app over. There are several ways to do this, here are a few I've tried:
  1. Install an ssh server app on your Android device and scp the app over. Alternately, set up an ssh server on your host PC/Mac, and use an ssh/scp client on Android to get the app. This is what I do, by using the OpenSSH package in Termux.
  2. Host the app in a web server and get it by using your Android browser or a downloader app.
  3. Setup the Android Debug Bridge (adb) on your device and use the SDK tools to push your files over.

Native compilation

  • Android Version 10 ("Q"), as LDC compiler support does not exist for Android Version 9 ("Pie") and earlier.
  • Termux for Android, available in the official Play Store, APKMirror, or F-Droid
  • LDC for Termux: apt install ldc With Android version 9 and earlier, the install will fail.

Cross-compilation setup

Once you have LDC and have unzipped the Android NDK, it's time to set up LDC for the desired Android target(s). See Cross-compiling with LDC for the general guide; I present two examples for a quick summary:

  • Targeting 32-bit Android/ARMv7-A on a Win64 host:
    1. Download the prebuilt android-armv7a package from GitHub matching the version of your LDC.
    2. Extract the lib directory into your LDC installation directory and rename it, e.g., to lib-android_armv7a.
    3. Open <LDC install dir>\etc\ldc2.conf in a text editor and append a section like this, adapting lib and NDK paths as needed:
"armv7a-.*-linux-android":
{
    switches = [
        "-defaultlib=phobos2-ldc,druntime-ldc",
        "-link-defaultlib-shared=false",
        "-gcc=C:/LDC/android-ndk-r21d/toolchains/llvm/prebuilt/windows-x86_64/bin/armv7a-linux-androideabi21-clang.cmd",
    ];
    lib-dirs = [
        "%%ldcbinarypath%%/../lib-android_armv7a",
    ];
    rpath = "";
};
  • Targeting 64-bit Android/AArch64 on a Linux host:
    1. Download the prebuilt android-aarch64 package from GitHub matching the version of your LDC.
    2. Extract the lib directory into your LDC installation directory and rename it, e.g., to lib-android_aarch64.
    3. Open <LDC install dir>/etc/ldc2.conf in a text editor and append a section like this, adapting lib and NDK paths as needed:
"aarch64-.*-linux-android":
{
    switches = [
        "-defaultlib=phobos2-ldc,druntime-ldc",
        "-link-defaultlib-shared=false",
        "-gcc=/home/me/android-ndk-r21d/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android21-clang",
    ];
    lib-dirs = [
        "%%ldcbinarypath%%/../lib-android_aarch64",
    ];
    rpath = "";
};

The prebuilt Android packages also include the corresponding x86 simulator libraries, so 32/64-bit x86 Android simulator targets can be set up the same way.

Build a command-line executable

Now that we have a D compiler setup for (one or more) Android targets, let's try building a small program, the classic Sieve of Eratosthenes single-core benchmark, which finds all prime numbers up to a number you choose. Install the curl package in Termux if you're natively compiling, apt install curl.

# Load this link in your browser and download the file otherwise 
curl -L -O https://raw.githubusercontent.com/dlang/dmd/master/samples/sieve.d

# Cross-compile & -link to ARMv7-A (on any host)
ldc2 -mtriple=armv7a--linux-androideabi sieve.d

# Cross-compile & -link to AArch64 (on any host)
ldc2 -mtriple=aarch64--linux-android sieve.d

# Compile & link natively in Termux
ldc2 sieve.d

Cross-compilation

Copy this sieve program onto an Android device or emulator and set its permissions with the chmod command. Here's how I do it in Termux, with an ssh server running on the host PC/Mac with IP address 192.168.1.37:

apt install openssh
cd
scp jo@192.168.1.37:sieve .
chmod 700 sieve

Run the sieve program

The sieve program will tell you how many prime numbers there are in the first n integers, a limit you can specify. Run this command to find how many primes there are in the first million integers:

./sieve 1000000

If you built sieve successfully, it should return

78498 primes

Build a sample OpenGL ES 1.0 GUI app ported to D

Clone the android repository or download its source in a zip file, which contains several headers and sample OpenGL apps from the NDK translated to D:

sudo apt-get install git # In Termux, apt install git
git clone https://github.com/Diewi/android.git
cd android

# Alternatively, without git:
curl -L -O https://github.com/Diewi/android/archive/build.zip
unzip build.zip
cd android-build

Then build the Native Activity app, which is written completely in D. D code for an apk must be compiled to a shared library, which the Android runtime will call:

cd samples/native-activity

ldc2 -I../.. jni/main.d ../../android/sensor.d ../../android_native_app_glue.d \
     -shared -of=libs/arm64-v8a/libnative-activity.so \ # or `libs/armeabi-v7a/...` for 32-bit ARM
     -L-soname -Llibnative-activity.so \
     -mtriple=aarch64--linux-android # only for cross-compilation; use `armv7a--linux-androideabi` for 32-bit ARM
     # possibly needed: -L-llog -L-landroid -L-lEGL -L-lGLESv1_CM

Cross-compilation

Ant approach

Finally, package the app as the SDK directs: at this point, it's just like building a regular Android app. I document the older Ant approach, which is deprecated, replace it with the Gradle command from a newer SDK. With Ant on Mac or Linux, set the path to your SDK, then run these commands:

export SDK=/path/to/your/android-sdk
$SDK/tools/android update project -p . -s --target 1
ant debug

Android Studio approach

Enter on your <application name>/app/src/main and create a folder called jniLibs, this folder is extremely important, it is the default folder to put your shared libraries to be imported together with your .apk. If you wish to use other name for it, you will need to change your gradle file. For actually putting your libraries inside that folder, you will actually need to make directories for the target architectures, so, create inside it:

  • armeabi-v7a (For that, it is commonly used ldc2(version)-android-armv7a/lib
  • arm64-v8a (This is our target right now, ldc2(version)-android-aarch64/lib)
  • x86 (It is the lib32 for armv7a -> ldc2(version)-android-armv7a/lib686
  • x86_64 (It is the lib32 for the aarch64 -> ldc2(version)-android-aarch64/lib-x86_64 For reference, check ndk abi guide from official android site: Android ABI Guide

After creating those folders, you can actually move your shared library inside one of them, just click on run and you're good to go.

---

Transfer the resulting bin/NativeActivity-debug.apk to your Android device, again shown here by using scp from the Termux app.

scp jo@192.168.1.37:android/samples/native-activity/bin/NativeActivity-debug.apk /sdcard/Download/

Native compilation

Follow the instructions below to package this native shared library into an Android apk.

Install and run the sample GUI app

Go to Settings->Security on your Android device and allow installation of apps from unknown sources, ie from outside the Play Store, then go to /sdcard/Download in your file manager and choose the NativeActivity-debug apk to install it. Open the app after installing or go to your app folder and run the app named NativeActivity: it'll show a black screen initially, then flash a bunch of colors when the screen is touched.

Build a sample OpenGL ES 2.0 GUI app mostly written in D, with some Java

This D app has not been ported to 64-bit Android/ARM yet, only 32-bit ARM compilation will work for now:

cd samples/Teapot

ldc2 -I../.. -Ijni -Jjni \
     ../../ndk_helper/GLContext.d \
     ../../ndk_helper/JNIHelper.d \
     ../../ndk_helper/gestureDetector.d \
     ../../ndk_helper/perfMonitor.d \
     ../../ndk_helper/shader.d \
     ../../ndk_helper/tapCamera.d \
     jni/TeapotNativeActivity.d \
     jni/TeapotRenderer.d \
     ../../android/sensor.d \
     ../../android_native_app_glue.d \
     -shared -of=libs/armeabi-v7a/libTeapotNativeActivity.so \
     -L-soname -LlibTeapotNativeActivity.so \
     -mtriple=armv7a--linux-androideabi # only for cross-compilation
     # possibly needed: -L-llog -L-landroid -L-lEGL -L-lGLESv2

Cross-compilation

Package this shared library into an apk by using the SDK, as you would normally, and try installing and running it on your device.

Native compilation

Install the right Eclipse Java compiler package for your device (the ecj4.6 package if you're running Android 5 or 6), the Android dex tool, and other packages needed to build an Android apk. Generate any Java files needed, compile and dex them, then package everything up into an apk and sign it.

apt install ecj dx aapt apksigner

aapt package  -M ./AndroidManifest.xml -I $PREFIX/share/java/android-21.jar -J src/ -S res -m

ecj-21 -d ./obj -sourcepath src $(find src -type f -name "*.java")

dx --dex --output=./classes.dex ./obj/

aapt package  -M ./AndroidManifest.xml -S res -A assets -F teapot.apk

aapt add teapot.apk classes.dex lib/armeabi-v7a/libTeapotNativeActivity.so

apksigner debug.ks teapot.apk teapot-signed.apk

Finally, move teapot-signed.apk into a public directory, from which you can install and run it.

Examples and useful repositories

  • D Android from adamdruppe - You can find android-setup.d which will download the pre-built Android runtimes for you and set up ldc2.conf;

Changes for Android

Now that you've seen some examples, here's a description of changes to D that have been made for Android.

The Android environment doesn't support native Thread-Local Storage (TLS), which is integral to D, since all static and global variables not explicitly marked shared/__gshared/immutable are thread-local by default in D. The Android D runtime supports emulated TLS instead, but this currently requires the ld.bfd linker - ld.gold or lld won't do.

If building a shared library and not a D command-line executable, you must also initialize and exit the D runtime by calling rt_init() and rt_term() before and after all D code is run, as has been done in the default Android wrapper (rt_init/rt_term are automatically inserted and run for a D executable). Running multiple D shared libraries is currently unsupported on Android, only a single D shared library that statically links against the D runtime will work.

Package an Android app from scratch on your Android device

Install aapt, the Android Asset Packaging Tool, and apksigner, a tool to create a hashed manifest and sign your apps.

apt install aapt apksigner

I'll demonstrate with the NativeActivity app built above.

cd samples/native-activity
aapt package -M AndroidManifest.xml -S res -F NativeActivity-debug-unsigned.apk
APK_DIR=armeabi-v7a # or `arm64-v8a` for 64-bit ARM
aapt add NativeActivity-debug-unsigned.apk libs/$APK_DIR/libnative-activity.so

This simple app only requires three files, AndroidManifest.xml, resources.arsc, and libs/$APK_DIR/libnative-activity.so, which you can check with the following aapt command.

aapt list NativeActivity-debug-unsigned.apk

Now let's generate a hashed manifest, just like a Java jar file, and sign the app. If you have your own Java Keystore already, just supply it to apksigner. If not, apksigner will generate a self-signed Keystore file, which we name debug.ks below, which is good enough to sign and install debug apps on your own Android device.

apksigner debug.ks NativeActivity-debug-unsigned.apk NativeActivity-debug.apk

You should see three additional files in the apk, if you list its contents using the command above. At this point, you can install and run the signed app on your own device. If you modify the app, you'll need to build the manifest and sign it again: make sure you use the debug.ks you created before or Android won't allow you to reinstall the same app with a newly generated key, unless you first uninstall the app.

Sign your app using a certificate and OpenSSL

Unfortunately, apksigner only supports Java Keystore files for signing right now and I don't know how to build one from scratch, so if you don't have a keystore and want to release your app to an app store, you'll have to use OpenSSL to sign the app.

For a valid certificate for the final release, there's plenty of information online on how to generate one. I'll just show how to create a self-signed certificate for debugging purposes.

First, install the OpenSSL package in Termux. Then, this OpenSSL command will generate a self-signed debug certificate, apk.cert, and a 2048-bit RSA private key, key.pem, which isn't encrypted with a password. It will ask you for some signing info, for which I've shown what's used by the debug certificate in the Android SDK, but it doesn't matter what you enter, as it's ignored:

apt install openssl-tool

openssl req -x509 -nodes -newkey rsa:2048 -keyout key.pem -out apk.cert

....................................+++
writing new private key to 'key.pem'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:US
State or Province Name (full name) [Some-State]:.
Locality Name (eg, city) []:
Organization Name (eg, company) [Internet Widgits Pty Ltd]:Android
Organizational Unit Name (eg, section) []:
Common Name (e.g. server FQDN or YOUR name) []:Android Debug
Email Address []:

Now that we have a certificate- self-signed in this case, use your actual release certificate if you want to release the app- and private key, we use them to sign the app. Since the apk is just a zip file, unzip it into a directory and use OpenSSL to generate a new signature file, CERT.RSA, then update the apk with the new signature, and copy the apk to a public user directory from which you can install it:

mkdir unpack
cd unpack/
unzip ../NativeActivity-debug.apk

cd META-INF/
openssl smime -sign -md sha1 -binary -noattr -in CERT.SF -out CERT.RSA -outform der -inkey ../../key.pem -signer ../../apk.cert

cd ..
aapt remove ../NativeActivity-debug.apk META-INF/CERT.RSA
aapt add ../NativeActivity-debug.apk META-INF/CERT.RSA

cd ..
cp NativeActivity-debug.apk /sdcard/Download/

The OpenSSL commands to generate a certificate and sign the apk were taken from this 2012 blog post, you can follow it further to see what the signature consists of and verify it for yourself. This 2013 blog post was critical for me to understand how apk signing works, I used to run all those commands by hand until the apksigner package was added to the Termux package repo.

Directions for future work

  • Revise the way TLS data is initialized on Android. ld.bfd is required because it's the only linker putting the .tdata and .tbss sections adjacent to each other (by default).
  • Integrate the linux shared library support in druntime's rt.sections_elf_shared, so that multiple D shared libraries can be used. Things may likely get complicated because of LDC's custom TLS emulation; using LLVM's default EmuTLS for Android instead might be an option.