Motivation:
• faster builds (on an Intel Core i9-9900K):
( ../configure --disable-sanitizers && make -j8; )
19,47s user 2,78s system 395% cpu 5,632 total
( meson .. -Dmans=true -Ddocs=true -Dprefix=/usr && ninja; )
38,67s user 3,73s system 1095% cpu 3,871 total
• more approachable build system configuration in the
python-esque meson domain specific language instead of
the autotools m4 macro language
• built-in language server support thanks to ninja:
the required compile_commands.json is built automatically
and only needs to be linked from the source dir, e.g.:
ln -s build/compile_commands.json .
Changes:
• the embedded vcs version info format changed from e.g.
4.18-282-gabe46f69 (2020-05-16, branch "next")
to:
4.18-282-gabe46f69
I think it’s better to lose a little bit of detail for
the gained cleanliness of using meson’s vcs_tag()
• Drop unused xcb-event dependency.
• We can no longer enable sanitizers and debug options
based on whether we are in a release or non-release build,
because our new version logic runs at ninja build time,
not at meson configure time.
The new behavior is probably for the better in terms of
what people expect, and we can make the CI use address sanitizer
explicitly to ensure it is still exercised.
• We lose the AX_EXTEND_SRCDIR behavior, i.e. including the
path component of the parent of the source dir in all paths.
This was a trick we used for easier debugging, so that stack
traces would contain e.g. ../i3-4.18.1/src/main.c, instead of
just src/main.c.
The other mechanism (_i3_version symbol) that we have for including
the version number in the “backtrace full” (but not merely
“backtrace”) output of gdb still works.
• Release tarballs now use tar.xz. Why not.
Migration plan
This commit adds the meson build files to the tree, but does not remove
autotools yet. For the development phase, we will keep both build systems
functional (and built on travis).
Then, just before the i3 v4.19 release, we will remove autotools from the tree
and the release tarball will require meson to compile.
This way, we incentivize maintainers to change, while also offering them an easy
way out (if desired) by reverting the most recent commit. In practice, switching
a distribution package from autotools to meson should only be a few line change,
easier than applying the provided patch :). Take a look at the debian/ changes
in this commit for an example.
meson is broadly available everywhere that i3 is available: Both xorg-server and
systemd gained meson build files in 2017, so we can follow suit:
https://anholt.livejournal.com/52574.htmlhttps://in.waw.pl/~zbyszek/blog/systemd-meson.html
How do I?
For producing a coverage report, enable the b_coverage meson base option
and run ninja coverage-html:
% cd build
% meson .. -Db_coverage=true
% ninja
% ninja test
% ninja coverage-html
See also https://mesonbuild.com/howtox.html#producing-a-coverage-report
For using the address sanitizer, memory sanitizer or undefined behavior
sanitizer, use the b_sanitize meson base option:
% cd build
% meson .. -Db_sanitize=address
% ninja
See also https://mesonbuild.com/Builtin-options.html#base-options
related to #4086
Also added hardening flags. We can't enable PIE because i3bar seems
to have problems with that. We also shouldn't enable bindnow, as it
the startup performance penalty (though probably not too bad) might
not be acceptable for i3-msg and i3-input.
