qemu: stop reconfiguring, and so rebuilding, QEMU on every build - #343
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daniel-rossier wants to merge 1 commit into
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`build.sh qemu` recompiled the whole of QEMU each time, even with nothing changed. do_configure is nostamp, so it re-ran ./configure on every invocation, and QEMU's configure starts with `rm -rf build` whenever build/ carries the auto-created-by-configure marker, which it always does after the first run. Every object was thrown away and the make that followed started from an empty build directory. do_configure now records the configure line it used in build/.ib-configure-args and skips ./configure when the line is unchanged. meson/ninja then rebuild incrementally, and still reconfigure themselves when a patch touches a meson.build. The record lives inside build/, so it goes away whenever configure recreates the directory. The target list is now emitted in a fixed order (arm-softmmu before aarch64-softmmu), so alternating virt32 and virt64 does not change the line and trigger a needless reconfigure once both targets are built. A second `build.sh qemu` with no change goes from a full rebuild (about 1m50s) to a few seconds.
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build.sh qemurecompiled the whole of QEMU on every run.do_configureis nostamp, so./configurere-ran each time, and QEMU's configure begins withrm -rf buildoncebuild/holds itsauto-created-by-configuremarker, which it always does after the first run. Every object was discarded beforemake.do_configurenow records its configure line inbuild/.ib-configure-argsand skips./configurewhen the line is unchanged. meson/ninja then rebuild incrementally, and still reconfigure themselves if a patch touches ameson.build. The record lives inbuild/, so it disappears whenever configure recreates the directory. The target list is emitted in a fixed order, so alternating virt32/virt64 does not change the line once both targets are built.Same change in so3, infrabase, micofe, edgem1 and pos_sol.
Tested (virt64): the first
build.sh qemuconfigures and builds (1m49s on so3, 1m19s on pos_sol), the second skips configure and finishes in 7s / 3.5s withqemu-system-aarch64produced. virt32↔virt64 alternation not exercised.