On 12/16/22 16:35, Daniel P. Berrangé wrote:
So after applying this series, at least on Fedora, I barely needed
configure at all, in so muc as the following successfully built AFAICT:
$ mkdir build
$ cat > build/config-host.mak <<EOF
all:
GIT=git
GIT_SUBMODULES=ui/keycodemapdb tests/fp/berkeley-testfloat-3
tests/fp/berkeley-softfloat-3 dtc
GIT_SUBMODULES_ACTION=update
CONFIG_POSIX=y
CONFIG_LINUX=y
SRC_PATH=/home/berrange/src/virt/qemu
TARGET_DIRS=x86_64-softmmu
CONFIG_PLUGIN=y
HAVE_GDB_BIN=/usr/bin/gdb
ENGINE=podman
ROMS=pc-bios/optionrom
MAKE=make
PYTHON=/usr/bin/python3 -B
GENISOIMAGE=/usr/bin/genisoimage
MESON=/usr/bin/meson
NINJA=/usr/bin/ninja
PKG_CONFIG=
CC=cc
EXESUF=
TCG_TESTS_TARGETS= x86_64-softmmu
EOF
$ meson build
$ ninja -C build
Yep. It wouldn't build the firmwares though, or be able to run TCG or
Avocado tests. This kind of build system orchestration is the remaining
task of configure (see new docs in patch 28). It's not really possible
for it to go away, it's beyond Meson's capabilities and intentions.
I would also like to move Python virtual environment configuration to
configure. This would give a lot more flexibility in whether to use
network or not, for example, and is in line with submodule handling that
is already in configure.
Out of the things in config-host.mak there, a few meson already knows,
like CC, SRC_PATH, 50% would be just a meson find_program() command,
a couple would need meson args (eg TARGET_DIRS), and some just look
redundant, eg CONFIG_LINUX largely duplicates __linux__, and
CONFIG_POSIX is effectively !_WIN32.
There are a couple like ENGINE or HAVE_GDB_BIN that are only needed by
non-QEMU parts of the build system, and I don't think it makes much
sense to move those detections out of configure.
But yeah, the OS symbols are pretty low-hanging fruit. In fact
meson.build recomputes them:
config_host_data.set('CONFIG_POSIX', targetos != 'windows')
... and with Windriver's patches to get much closer to POSIX/Windows
feature parity, the Makefiles don't use them as much as they did.
Paolo
