Android NDK and M1 Processors: A Step-by-Step Guide to Building a Compatible Library

The Android NDK is a powerful tool that enables developers to build native applications for Android devices using the C and C++ programming languages. One of its key features is support for cross-platform compilation of ARM SIMD, also known as Neon. In this article, we will explore how to use the NDK with M1 processors, which are relatively new to the market.

Enabling Neon Support

To enable Neon support in your Android project, you need to add the following lines to your CMakeLists.txt file:

```

if(ANDROID_ABI STREQUAL armeabi-v7a)

set_target_properties(${TARGET_NAME} PROPERTIES ARME_NEON 1)

endif()

```

Alternatively, if you are using the ndk-build module, you can add the following line to your Android.mk file:

```

LOCAL_ARM_NEON := true

```

Disabling Neon Support

If you need to disable Neon support for non-Neon devices, you can use the following code in your CMakeLists.txt file:

```

if(ANDROID_ABI STREQUAL armeabi-v7a)

set_target_properties(${TARGET_NAME} PROPERTIES ARME_NEON 0)

endif()

```

Alternatively, if you are using the ndk-build module, you can add the following line to your Android.mk file:

```

LOCAL_ARM_NEON := false

```

Building for M1 Processors

To build your application for M1 processors, you need to use a compatible toolchain. The NDK r21e version does not support M1 processors out of the box, but you can build it manually using the following steps:

1. Download the NDK r21e source code from the official Android website.

2. Extract the zip file and navigate to the `ndk/toolchains/llvm/prebuilt/darwin-x86_64` directory.

3. Update the `toolchain.cmake` file by adding the following lines:

```

set(CMAKE_CXX_COMPILER '/path/to/m1-toolchain/bin/clang++')

set(CMAKE_C_COMPILER '/path/to/m1-toolchain/bin/clang')

```

4. Build the NDK using the following command:

```

cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=/path/to/ndk/toolchains/llvm/prebuilt/darwin-x86_64/toolchain.cmake ..

```

5. Wait for the build process to complete.

In this article, we have explored how to use the Android NDK with M1 processors. We have seen how to enable and disable Neon support, as well as how to build a compatible toolchain using the NDK r21e source code. With these steps, you should be able to build your application for M1 processors and run it on your device.

Android ndk m1