fpc-for-android

An example repository showing how to build the Free Pascal Compiler to allow cross-compilation for Android.

The two Containerfiles

The repository contains two slightly different Containerfiles:

• The default Containerfile takes a very from-the-ground-up approach, basing on the Ubuntu 22.04 LTS container image. A copy of the Android NDK is required for the build. The FPC cross-compiler is installed system-wide. The end result is a smaller, if more bare-bones, image. Most notably, it includes only the Android NDK, and not the SDK - meaning that while you can use it to compile code, you can't actually create an .apk.

• The alternative Containerfile-cimg is based on one of the Circle CI for Android container images. The FPC cross-compiler is installed only for the default user. The end result is a more comprehensive, if bloated, image.

Pre-built container images

Pre-built container images are available for download from Docker Hub.

• The default image: docker.io/suvepl/fpc-for-android:bare

• The cimg image: docker.io/suvepl/fpc-for-android:cimg

For both of these images, the target Android API level is set to 21 (Android 5.0 "Lollipop").

Building the images yourself

To build the container images, you'll need the following:

• Android Native Development Kit r21d (not needed for the -cimg image)
• Buildah / Docker
• Free Pascal Compiler v3.2.2 sources

Android tools

You can download the Android Native Development Kit from the Android developer portal.

Make sure to grab the r21d release, as - for the time being - the build scripts do not support newer versions.

Free Pascal Compiler source code

You can download the FPC source code from the FPC downloads page. Make sure to grab the fpcbuild-X.Y.Z archive, not fpc-source.

Picking the target Android API level

Before you can proceed, you may want to take a moment to think about which Android API level (i.e. NDK platform) you'll want to target. You need to make this decision now, for two reasons:

1. FPC itself is built against a specific API level; in order to use a different level, the compiler must be rebuilt.
2. For the default image, the build process includes a "slimming" script that removes any files pertaining to unused API levels.

If you do not specify a level, the default value is 21.

Performing the build

Assuming you've downloaded both the Android NDK and FPC sources and placed them in the same directory as the Containerfile, all that's left to do now is:

$ buildah bud --build-arg ANDROID_API=LEVEL -t fpc-android ./

Or, if you're using Docker:

$ docker build --build-arg ANDROID_API=LEVEL -t fpc-android ./

The build process can be rather lengthy, as it builds the Free Pascal Compiler four times over:

1. First, it builds an x86_64-linux compiler. This is used to ensure that you'll be using the downloaded version, with any patches bundled within this repository applied, and not the version found in the Ubuntu repository (which may be older). This step also compiles all the Run-Time Library and Free Component Library units redistributed along with the compiler.

2. Second, a cross-compiler for aarch64-android (64-bit ARM) is built, along with the RTL and FCL units.

3. Third, the compiler + RTL + FCL combo is built for arm-android (32-bit ARM).

4. Lastly, the same is done for x86_64-android. The x86_64 Android target is mostly useful for debugging your apps in the Android Simulator.

Note that the x86-android (for 32-bit Intel/AMD processors) target is *NOT* included here.

Licensing

The contents of this repository are subject to the zlib licence. For the full text of the licence, consult the LICENCE file.