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

2.1.1 If build llvm from source

    $ git clone https://github.com/llvm/llvm-project.git
    $ mkdir build
    $ cd build
    $ cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=ON \
        -DBUILD_SHARED_LIBS=OFF -DLLVM_PARALLEL_LINK_JOBS=1 -DLLVM_INCLUDE_TESTS=OFF \
        -DLLVM_ENABLE_RTTI=ON -DCMAKE_INSTALL_PREFIX=/path/to/llvm/install \
        -DLLVM_ENABLE_PROJECTS="clang" ../llvm-project
    $ ninja
    $ ninja install

2.1.2 Build autofdo tools

    $ 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=. -DLLVM_PATH=/path/to/llvm/install ../   
    $ ninja
    $ ninja test

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