Bootstrap aarch64-linux-android clang/llvm toolchain with sanitizers support

bootstrap.sh

#!/bin/bash
# script that creates clang/llvm cross toolchain for aarch64 android target
# compile a hello world program that runs on AOSP Android:
# test with: adb push hello /data/cache && adb shell /data/cache/hello
# GCC:
# C: aarch64-linux-android-gcc hello.c -o hello -pie
# C++: aarch64-linux-android-g++ hello.cc -o hello -pie -fPIC -static-libgcc \
# -nostdlib -L/usr/local/aarch64-linux-android/lib -lc++ -lc -nostdinc++ \
# -I/usr/local/aarch64-linux-android/include/c++/v1 -std=c++11
# Clang/LLVM:
# C: /usr/local/aarch64-linux-android/bin/clang hello.c -o hello
# C++: /usr/local/aarch64-linux-android/bin/clang++ hello.cc -o hello \
# --stdlib=libc++ --rtlib=compiler-rt
# C++ with sanitizers (ubsan as an example):
# /usr/local/aarch64-linux-android/bin/clang++ hello.cc -o hello --stdlib=libc++ \
# -fsanitize=undefined -static-libsan --rtlib=compiler-rt

set -e

# set the environment variables
export TARGET=aarch64-linux-android
export PREFIX=/usr/local/$TARGET

# set up repositories
mkdir crossllvm && cd crossllvm
for a in llvm compiler-rt libunwind libcxx libcxxabi; do
    git clone http://llvm.org/git/$a.git --depth=1
done
pushd llvm/tools && \
    git clone http://llvm.org/git/clang.git --depth=1 && \
    popd

# install GNU binutils
# copy headers into $PREFIX/$TARGET/sys-include
# copy crt*.o lib{c,m,dl}.so to $PREFIX/lib64 and $PREFIX/$TARGET/lib
# install GCC

# llvm + clang
mkdir build && cd build
cmake ../llvm  -G Ninja \
    -DCMAKE_BUILD_TYPE:STRING=Release \
    -DCMAKE_INSTALL_PREFIX=$PREFIX \
    -DLLVM_TARGETS_TO_BUILD=AArch64 \
    -DLLVM_DEFAULT_TARGET_TRIPLE=$TARGET \
    -DLLVM_OPTIMIZED_TABLEGEN=ON \
    -DBUILD_SHARED_LIBS=ON
ninja && sudo ninja install
cd ..

# compiler-rt builtins
cd compiler-rt && mkdir build && cd build
cmake .. -G Ninja \
    -DCMAKE_C_COMPILER="$PREFIX/bin/clang" \
    -DCMAKE_C_FLAGS="-isystem $PREFIX/$TARGET/sys-include" \
    -DCMAKE_AR=$PREFIX/bin/llvm-ar \
    -DCMAKE_NM=$PREFIX/bin/llvm-nm \
    -DCMAKE_RANLIB=$PREFIX/bin/llvm-ranlib \
    -DCMAKE_INSTALL_PREFIX=$PREFIX/lib/clang/7.0.0 \
    -DLLVM_CONFIG_PATH=$PREFIX/bin/llvm-config \
    -DCOMPILER_RT_BUILD_BUILTINS=ON \
    -DCOMPILER_RT_BUILD_SANITIZERS=OFF \
    -DCOMPILER_RT_BUILD_XRAY=OFF \
    -DCOMPILER_RT_BUILD_LIBFUZZER=OFF \
    -DCOMPILER_RT_BUILD_PROFILE=OFF
ninja && sudo ninja install
cd ../..

# libunwind
cd libunwind && mkdir build && cd build
cmake .. -G Ninja \
    -DCMAKE_C_COMPILER="$PREFIX/bin/clang" \
    -DCMAKE_CXX_COMPILER="$PREFIX/bin/clang++" \
    -DCMAKE_CXX_FLAGS="-isystem $PREFIX/$TARGET/sys-include" \
    -DCMAKE_AR="$PREFIX/bin/llvm-ar" \
    -DCMAKE_NM="$PREFIX/bin/llvm-nm" \
    -DCMAKE_RANLIB="$PREFIX/bin/llvm-ranlib" \
    -DCMAKE_INSTALL_PREFIX="$PREFIX" \
    -DLLVM_CONFIG_PATH="$PREFIX/bin/llvm-config"
ninja && sudo ninja install
cd ../..

# libcxxabi
cd libcxxabi && mkdir build && cd build
cmake .. -G Ninja \
    -DCMAKE_C_COMPILER="$PREFIX/bin/clang" \
    -DCMAKE_CXX_COMPILER="$PREFIX/bin/clang++" \
    -DCMAKE_CXX_FLAGS="-isystem $PREFIX/$TARGET/sys-include" \
    -DCMAKE_AR="$PREFIX/bin/llvm-ar" \
    -DCMAKE_NM="$PREFIX/bin/llvm-nm" \
    -DCMAKE_RANLIB="$PREFIX/bin/llvm-ranlib" \
    -DCMAKE_INSTALL_PREFIX="$PREFIX" \
    -DLLVM_CONFIG_PATH="$PREFIX/bin/llvm-config" \
    -DLIBCXXABI_LIBCXX_INCLUDES="../../libcxx/include" \
    -DLIBCXXABI_USE_COMPILER_RT=ON \
    -DLIBCXXABI_USE_LLVM_UNWINDER=ON \
    -DLIBCXXABI_ENABLE_STATIC=ON \
    -DLIBCXXABI_ENABLE_SHARED=ON
ninja && sudo ninja install
sudo cp -R ../include $PREFIX/include/libcxxabi
cd ../..

# libcxx
# warning: rebase to drop commit 85a7702b4cc5d69402791fe685f151cf3076be71
# libcxx head NDK version too new; we have r14
# https://reviews.llvm.org/D46558
cd libcxx && mkdir build && cd build
TODELETE=85a7702b4cc5d69402791fe685f151cf3076be71
pushd .. && \
    git fetch --unshallow && \
    git rebase $TODELETE --onto $TODELETE^ && \
    popd
cmake .. -G Ninja \
    -DCMAKE_C_COMPILER="$PREFIX/bin/clang" \
    -DCMAKE_CXX_COMPILER="$PREFIX/bin/clang++" \
    -DCMAKE_CXX_FLAGS="-isystem $PREFIX/$TARGET/sys-include" \
    -DCMAKE_AR="$PREFIX/bin/llvm-ar" \
    -DCMAKE_NM="$PREFIX/bin/llvm-nm" \
    -DCMAKE_RANLIB="$PREFIX/bin/llvm-ranlib" \
    -DCMAKE_INSTALL_PREFIX="$PREFIX" \
    -DLLVM_CONFIG_PATH="$PREFIX/bin/llvm-config" \
    -DLIBCXX_CXX_ABI="libcxxabi" \
    -DLIBCXX_CXX_ABI_INCLUDE_PATHS="$PREFIX/include/libcxxabi" \
    -DLIBCXX_USE_COMPILER_RT=ON
ninja && sudo ninja install
cd ../..

# statically link libunwind and libc++abi into libc++ to match Android behavior
pushd $PREFIX/lib
sudo mv libc++.so libc++.so.old
sudo /usr/local/aarch64-linux-android/bin/clang -shared \
    -o libc++.so -Wl,--whole-archive libc++.a libc++abi.a libunwind.a \
    -Wl,--no-whole-archive
popd

# compiler-rt non-builtin
# warning: bionic headers lack some definitions to compile
# apply https://gist.github.com/KireinaHoro/141d27321b2aab27fa8292b1bd0f7105
# to bionic headers before continuing
cd compiler-rt
# clean up build directory remains when building builtins
rm -rf build && mkdir build && cd build
cmake .. -G Ninja \
    -DCMAKE_C_COMPILER="$PREFIX/bin/clang" \
    -DCMAKE_C_FLAGS="-isystem $PREFIX/$TARGET/sys-include" \
    -DCMAKE_CXX_COMPILER="$PREFIX/bin/clang++" \
    -DCMAKE_CXX_FLAGS="-isystem $PREFIX/$TARGET/sys-include" \
    -DCMAKE_AR=$PREFIX/bin/llvm-ar \
    -DCMAKE_NM=$PREFIX/bin/llvm-nm \
    -DCMAKE_RANLIB=$PREFIX/bin/llvm-ranlib \
    -DCMAKE_INSTALL_PREFIX=$PREFIX/lib/clang/7.0.0 \
    -DLLVM_CONFIG_PATH=$PREFIX/bin/llvm-config \
    -DCOMPILER_RT_BUILD_BUILTINS=OFF \
    -DCOMPILER_RT_BUILD_SANITIZERS=ON \
    -DCOMPILER_RT_BUILD_XRAY=ON \
    -DCOMPILER_RT_BUILD_LIBFUZZER=ON \
    -DCOMPILER_RT_BUILD_PROFILE=ON
ninja && sudo ninja install