[toc]

1 Features

• Support to build cpp application or library with bazel platform
• Support to build golang application or library with bazel platform
• Support to build android jni library with bazel platform(generate jni header automatically, end-to-end)
• Support to build android application(non-platform)

2 Environment

• WSL,Ubuntu18.04
• Bazel 3.3+
• Android JNI Library
  • Local JDK 8+(just for using javah or javac to generate native headers)
    • sudo apt install openjdk-8-jdk-headless
  • Android sdkmanager (https://developer.android.com/studio#command-tools)
    • config the environment of sdkmanager
    • sdkmanager --sdk_root=$HOME/Android --list
    • sdkmanager --sdk_root=$HOME/Android 'build-tools;29.0.2'
    • sdkmanager --sdk_root=$HOME/Android 'platforms;android-28'
    • sdkmanager --sdk_root=$HOME/Android --install "ndk;18.1.5063045"
      • more older releases: https://developer.android.com/ndk/downloads/older_releases ,also you can get the support list by --list

$ sudo apt-get install gcc
$ sudo apt-get install g++
$ sudo apt-get install gcc-arm-linux-gnueabihf
$ sudo apt-get install g++-arm-linux-gnueabihf

3 Non-Platform

3.1 Enable

1. Open .bazelrc file:

build   --toolchain_resolution_debug

# --------------------------
# Way1: enable/disable --crosstool_top,--cpu
# --------------------------
build:compiler_config --crosstool_top=//toolchains/cpp:compiler_suite
build:compiler_config --cpu=ubuntu_gcc
build:compiler_config --host_crosstool_top=@bazel_tools//tools/cpp:toolchain

# --------------------------
# Way2: enable/diable platform
# --------------------------
#build   --incompatible_enable_cc_toolchain_resolution

2. Open toolchains/cpp/BUILD, and comment generate_toolchains function, and uncomment generate_toolchain_suite function.

3.2 Default Build(cpu=k8)

To build this example you can use:

$ bazel build //cpp:hello-world

This compilation will only use the default compiler of the local machine.

3.3 Cross Build

• step1: config your toolchains path: toolchain/cpp/supported.bzl
• step2: build

# Default compilation configuration, --cpu : ubuntu_gcc
$ bazel build --config=compiler_config //cpp:hello-world
# Specify the toolchain to compile the target
$ bazel build --config=compiler_config --cpu=ubuntu_arm_linux_gnueabihf //cpp:hello-world

4 Platform & Mixed Language

• cpp
• golang

4.1 Enable

1. Open .bazelrc file:

build   --toolchain_resolution_debug

# --------------------------
# Way1: enable/disable --crosstool_top,--cpu
# --------------------------
#build:compiler_config --crosstool_top=//toolchains/cpp:compiler_suite
#build:compiler_config --cpu=ubuntu_gcc
#build:compiler_config --host_crosstool_top=@bazel_tools//tools/cpp:toolchain

# --------------------------
# Way2: enable/diable platform
# --------------------------
build   --incompatible_enable_cc_toolchain_resolution

2. Open toolchains/cpp/BUILD, and comment generate_toolchain_suite function, and uncomment generate_toolchains function.

4.2 Query

# to view all supported platforms
$ bazel cquery "//platforms:all"

# to view all android_sdk targets generated by android_sdk_repository
$ bazel query "kind(android_sdk, @androidsdk//...)"

4.3 Build

4.3.1 C/C++

# p_ubuntu_gcc
$ bazel build cpp:hello-world --platforms=//platforms:p_ubuntu_gcc

# p_ubuntu_arm_linux_gnueabihf
$ bazel build cpp:hello-world --platforms=//platforms:p_ubuntu_arm_linux_gnueabihf

4.3.2 Golang

$ bazel build --platforms=@io_bazel_rules_go//go/toolchain:linux_amd64 golang/cmd/hello
$ bazel build --platforms=@io_bazel_rules_go//go/toolchain:linux_arm //golang/cmd/hello

4.3.3 All

# build all targets
$ bazel build --platforms=//platforms:p_ubuntu_gcc //...

4.3.4 Remote caching

# Remote caching
$ bazel clean
$ bazel build --remote_cache=grpc://10.151.176.11:8980 cpp:hello-world --platforms=//platforms:p_ubuntu_arm_linux_gnueabihf

4.3.5 JNI library

# Only Build Android JNI Library
$ bazel build --platforms=//platforms:p_android_armv7a android:gen_jni_header
$ bazel build --platforms=//platforms:p_android_armv7a android:jni_lib_shared
$ bazel build --platforms=//platforms:p_android_aarch64 android:jni_lib_shared

4.3.6 Android APK

# Build and Install Android Application(including jni/java library)
# First, you need to turn off the bazel platform feature in .bazelrc
# archs: armeabi-v7a/arm64-v8/x86
# way1
$ bazel build android/demo/app/src/main:app --fat_apk_cpu=arm64-v8a
# way2
$ bazel build android/demo/app/src/main:app --config=android_arm64-v8a
# Install apk
# Maybe you'll have this problem: https://github.com/bazelbuild/examples/issues/120
# way1
$ bazel mobile-install android/demo/app/src/main:app
# way2
$ adb install bazel-bin/android/demo/app/src/main/app.apk

# view APK package information
$ zipinfo -l app.apk
# view application stack information
$ adb shell dumpsys meminfo net.xiaobaiai.app

5 Platform Configuration

All toolchain information is in file toolchains/cpp/supported.bzl.