This patch adds libc++ support for Android L (Android 5.0+) and up,
tested using the Android team's current compiler, a recent version of
the AOSP sysroot, and the x86[-64] Android Emulator.
CMake and Lit Configuration:
Add runtimes/cmake/android/Arch-${ARCH}.cmake files that configure
CMake to cross-compile to Android without using CMake's built-in NDK
support (which only works with an actual packaged NDK).
Add libcxx/cmake/caches/AndroidNDK.cmake that builds and tests libc++
(and libc++abi) for Android. This file configures libc++ to match what
the NDK distributes, e.g.:
- libc++_shared.so (includes libc++abi objects, there is no libc++abi.so). libunwind is linked statically but not exported.
- libc++_static.a (does not include libc++abi) and libc++abi.a
- std::__ndk1 namespace
- All the libraries are built with __ANDROID_API__=21, even when they are linked to something targeting a higher API level.
(However, when the Android LLVM team builds these components, they do
not use these CMake cache files. Instead they use Python scripts to
configure the builds. See
https://android.googlesource.com/toolchain/llvm_android/.)
Add llvm-libc++[abi].android-ndk.cfg.in files that test the Android
NDK's libc++_shared.so. These files can target old or new Android
devices. The Android LLVM team uses these test files to test libc++ for
both arm/arm64 and x86/x86_64 architectures.
The Android testing mode works by setting %{executor} to adb_run.py,
which uses adb push and adb shell to run tests remotely. adb_run.py
always runs tests as the "shell" user even on an old emulator where
"adb unroot" doesn't work. The script has workarounds for old Android
devices. The script uses a Unix domain socket on the host
(--job-limit-socket) to restrict concurrent adb invocations. Compiling
the tests is a major part of libc++ testing run-time, so it's desirable
to exploit all the host cores without overburdening the test devices,
which can have far fewer cores.
BuildKite CI:
Add a builder to run-buildbot, android-ndk-*, that uses Android Clang
and an Android sysroot to build libc++, then starts an Android emulator
container to run tests.
Run the emulator and an adb server in a separate Docker container
(libcxx-ci-android-emulator), and create a separate Docker image for
each emulator OS system image. Set ADB_SERVER_SOCKET to connect to the
container's adb server. Running the only adb server inside the
container makes cleanup more reliable between test runs, e.g. the adb
client doesn't create a ~/.android directory and the adb server can
be restarted along with the emulator using docker stop/run. (N.B. The
emulator insists on connecting to an adb server and will start one
itself if it can't connect to one.)
The suffix to the android-ndk-* job is a label that concisely specifies
an Android SDK emulator image. Enable CI testing on two configurations:
- "system-images;android-21;default;x86" ==> 21-def-x86
- "system-images;android-33;google_apis;x86_64" ==> 33-goog-x86_64
Mark tests XFAIL for Android:
Add three Android lit features:
- android
- android-device-api=(21,22,23,...)
- LIBCXX-ANDROID-FIXME (for failures that need follow-up work)
Mark failing test with XFAIL (and sometimes UNSUPPORTED):
- Disable various FS tests (because SELinux blocks FIFO and hard linking).
- Disable various locale tests (because Bionic has limited locale support).
You aren't caching this, so it won't have any effect. It's also the default though, so you don't need to specify it explicitly.