1. Install prerequisite

    $ sudo apt install libunwind-dev libgflags-dev libssl-dev libelf-dev protobuf-compiler

To build autofdo tool for llvm, it needs llvm major version >= 10. You can either install llvm using command like "sudo apt install llvm-10", or you can build the latest llvm from source.

To build autofdo tool for gcc, no llvm installation is needed.

2. Commands

2.1 Build autofdo tool for llvm

    $ git clone --recursive https://github.com/google/autofdo.git
    $ cmake -G Ninja -DWITH_LLVM=On -DCMAKE_BUILD_TYPE=Release -S autofdo/ -B Build/
    $ ninja -C Build

2.2 Build autofdo tool for gcc

2.2.1 Build autofdo tools using system gcc

    $ git clone --recursive https://github.com/google/autofdo.git
    $ cd autofdo
    $ mkdir build
    $ cd build
    $ # Note: "-DCMAKE_INSTALL_PREFIX=." must be used, because there is a bug in the basil cmakelist.
    $ cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=. ../   
    $ ninja

2.2.2 Build autofdo tools using customized built gcc

1. download gcc tarball, for example, gcc-11.2.0.tar.gz (other versions of gcc are similar), and extract
2. download prerequisites by

    $ cd gcc-release-11.2.0
    $ ./contrib/download_prerequisites

3. config, build and install gcc

    $ cd gcc-release-11.2.0
    $ mkdir build
    $ cd build
    $ ../gcc-releases-gcc-11.2.0/configure \
          --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu \
          --prefix=${HOME}/installs/gcc-11.2.0 \
          --enable-checking=release \
          --enable-languages=c,c++ \
          --disable-multilib \
          --program-suffix=-11.2
    $ make -j24 install

4. config autofdo and build:

    $ export PATH=${HOME}/installs/gcc-11.2.0/bin:$PATH
    $ CXX=${HOME}/installs/gcc-11.2.0/bin/x86_64-linux-gnu-g++-11.2
    $ CC=${HOME}/installs/gcc-11.2.0/bin/x86_64-linux-gnu-gcc-11.2

    $  mkdir -p build-with-gcc
    $  cd build-with-gcc
    $  cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=. \
        -DCMAKE_C_COMPILER="$CC" -DCMAKE_CXX_COMPILER="$CXX" ../autofdo