Building GCC from source - chhwang/devel-note GitHub Wiki

1. Download Ubuntu package source code named gcc-x_x.y.z.orig.tar.gz. Example link: gcc-8 8.2.0-1ubuntu2

2. Extract and compile. Referred from GCC wiki.

   tar xzf gcc-8_8.2.0.orig.tar.gz
   cd gcc-8_8.2.0
   tar xf gcc-8.2.0.tar.xz
   cd gcc-8.2.0
   ./contrib/download_prerequisites
   cd ..
   mkdir objdir
   cd objdir
   $PWD/../gcc-8.2.0/configure --prefix=$HOME/gcc-8.2.0 --enable-languages=c,c++,fortran,go --disable-multilib
   make
   make install
   

   --prefix means installation path.

3. Update alternatives for /usr/bin/gcc.

   sudo update-alternatives --install /usr/bin/gcc gcc $HOME/gcc-8.2.0 90
   sudo update-alternatives --config gcc
   

   The number 90 means priority of this alternative (larger number higher priority).

Tip 1: some versions do have compile bugs. Search for patches or select another version.

Tip 2: --disable-multilib means we use only for 64-bit machines. In my case make failed when this option is missing in configuration.

Tip 3: gcc-5.4.0 has a bug that the make fails if g++ is not already installed .