In this article we will see various steps to test/try emacs-28 with native compilation support on Ubuntu 20.04LTS. We will not touch existing emacs installed using apt on the Ubuntu, but will manually compile another version of emacs-28 with native-compilation support (called gccemacs henceforth) in the ~/opt/emacs-native folder. These two versions of emacs (already installed and gccemacs) will use different config files (init.el) and user-directories (~/.emacs.d) using chemacs2, so that they don't interfere with each other. Using this approach users can try gccemacs without breaking their stable emacs config.

Please help us improving this wiki by reporting any bugs/issues in the wiki github repo.

¶Installing gccemacs

check for any errors during ./configure step, you may be missing some libraries, which need to be installed using apt.

mkdir -p ~/opt
mkdir -p ~/opt/emacs-native
cd ~/opt
sudo add-apt-repository ppa:ubuntu-toolchain-r/ppa
sudo apt install gcc-10 g++-10 libgccjit0 libgccjit-10-dev libjansson4 libjansson-dev
sudo apt install libxpm-dev libgif-dev libtiff-dev libgnutls28-dev libmagick++-dev
git clone git://git.sv.gnu.org/emacs.git gccemacs
cd gccemacs
git checkout master
export CC=/usr/bin/gcc-10 CXX=/usr/bin/gcc-10
./autogen.sh
./configure --with-cairo --with-modules --without-compress-install --with-x-toolkit=no --with-gnutls --without-gconf --without-xwidgets --without-toolkit-scroll-bars --without-xaw3d --without-gsettings --with-mailutils --with-native-compilation --with-json --with-harfbuzz --with-imagemagick --with-jpeg --with-png --with-rsvg --with-tiff --with-wide-int --with-xft --with-xml2 --with-xpm CFLAGS="-O3 -mtune=native -march=native -fomit-frame-pointer" prefix=~/opt/emacs-native
make -j2 NATIVE_FULL_AOT=1
make install

¶Using emacs-profiles

• Install chemacs2 using following script

[ -f ~/.emacs ] && mv ~/.emacs ~/.emacs.bak
[ -d ~/.emacs.d ] && mv ~/.emacs.d ~/.emacs.default
git clone https://github.com/plexus/chemacs2.git ~/.emacs.d

• save following in ~/.emacs-profile.el

(
 ("default" . ((user-emacs-directory . "~/.emacs.default")
  (server-name . "default-server")))
 ("gccemacs" . ((user-emacs-directory . "~/.gccemacs.d")
  (server-name . "gccemacs-server")))
)

• copy your default config init.el to gccemacs folder

mkdir -p ~/.gccemacs.d
cp ~/.emacs.default/init.el ~/.gccemacs.d/init.el

¶Some changes in config file for gccemacs

• You can add following lines in your new init.el (in the ~/.gccemacs.d folder)just to check if native-compilation and native json is working

(setq comp-deferred-compilation t)

(if (and (fboundp 'native-comp-available-p)
       (native-comp-available-p))
  (message "Native compilation is available")
(message "Native complation is *not* available"))

(if (functionp 'json-serialize)
  (message "Native JSON is available")
(message "Native JSON is *not* available"))

• straight.el uses its own native compilation which can create some problems. You can switch off this using :build (:not native-compile), for e.g. in case of doom-themes, one can use the following

(use-package doom-themes
  :straight '(doom-themes :build (:not native-compile))
  :init
  (load-theme 'doom-nord t)
)

¶Running parallel emacs

¶default emacs

• run emacs without daemon (It is better to run this if you are running emacs first time after making all changes using chemacs2). Try it 2-3 times so that no error/installation is left.

emacs --with-profile=default

• If you are emacs daemon user then following will work

emacs --with-profile=default --daemon

• run a instance of daemon using (after previous step)

emacsclient -c -s /run/user/1000/emacs/default-server

¶gccemacs

• run emacs without daemon (It is better to run this if you are running emacs first time after making all changes using chemacs2). Try it 2-3 times so that no error/installtion is left.

~/opt/emacs-native/bin/emacs --with-profile=gccemacs

• If you are emacs daemon user then following will work

~/opt/emacs-native/bin/emacs --with-profile=gccemacs --daemon

• run a instance of daemon using (after previous step)

~/opt/emacs-native/bin/emacsclient -c -s /run/user/1000/emacs/gccemacs-server

¶Issues/Bugs and the solutions

• Some packages like vterm, pdf-tools couldn't compile for first time, but after restarting the computer somehow, they are working fine.
• Many packages show lot of warning messages. This happens when you are using these packages for first time. Shouldn't be a problem after that.
• Some user reported problem using exwm, didn't try it yet.