Features/Meson

What's next?

Blockers for further conversions

Complete moving installation rules to meson.build

Marc-André and Paolo already have patches for this. You're welcome to propose yourself for helping!

Benefit: allows removing parts of Makefile, leaving it as just an orchestrator for submodules, Makefile.ninja and Makefile.mtest

Complete moving build rules to meson.build

Move the build rules from tests/Makefile.include to tests/meson.build. You can take inspiration from tests/qtest/Makefile.include.

Marc-André and Paolo also have patches to convert the build rules in roms/ and pc-bios/

Benefit: allows removing CFLAGS, LDFLAGS, LIBS and LIBS_SOFTMMU, as well as most if not all of rules.mak.

Relocatable install

Not really related to Meson, but it allows removing the pre_prefix hack in the configure script.

Benefit: on Windows only /usr/share/qemu is relocatable, everything else (icons etc.) is not. POSIX is currently not relocatable and would get it for free.

Easy

Move pkg-config tests to meson.build

Replace declare_dependency statements with dependency statements

Benefit: allows removing *_CFLAGS and *_LIBS variables from config-host.mak. Allows using dependency objects instead of CONFIG_* symbols when declaring sourcesets.

Change simple config-host.mak symbols to Meson options

Some symbols (e.g. CONFIG_PARALLELS) are only used placed in config-host.mak to be read from Meson. Instead pass them through -D... command-line options

Benefit: allows removing CONFIG_* variables from config-host.mak.

Medium

"Handle (faked-up) in-tree build

And cleanup code to handle in-tree builds in configure. Or fail gracefully and explain the situation (which would be easier).

Benefit: simpler upgrade path

Include config-target.mak files in the tree

Remove the configuration loop in configure and just include the content of the .mak files directly in the tree, for example in a target/configs/ directory. (There are some small complications because config-target.mak file currently includes the host disassembler symbols too, e.g. CONFIG_I386_DIS).

Benefit: remove large swaths of imperative code, remove *-linux-user and *-softmmu directories from the build tree.

Move other compile tests from configure to meson.build

Hard(er)

Create configure help and command line parsing code from meson_options.txt.

Write a program that takes the output of "meson introspect --buildoptions" and generates shell code to initialize variables, parse command line options, print the help and create -D command line options for meson. May only make sense once many or most options are converted.

Benefit: remove code duplication, centralize command line handling

TBD

Get rid of ninjatool and just require Ninja

Benefit: 1000 lines of code go away

Disadvantage: recursive build re-enters through the window