Am 12.10.2012 23:39, schrieb Michael Roth: > On Fri, Oct 05, 2012 at 10:24:30AM +0200, Paolo Bonzini wrote: >> Il 04/10/2012 19:33, Michael Roth ha scritto: >>> + >>> +%.qidl.c: %.c $(SRC_PATH)/qidl.h $(addprefix $(SRC_PATH)/scripts/,lexer.py >>> qidl.py qidl_parser.py qapi.py qapi_visit.py) >>> + $(call rm -f $(*D)/qidl-generated/$(*F).qidl.c) >>> + $(if $(strip $(shell grep "QIDL_ENABLE()" $< 1>/dev/null && echo >>> "true")), \ >>> + $(call quiet-command, \ >>> + $(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(CFLAGS) -E -c -DQIDL_GEN $< >>> | \ >>> + $(PYTHON) $(SRC_PATH)/scripts/qidl.py \ >>> + --output-filepath=$(*D)/qidl-generated/$(*F).qidl.c || [ "$$?" -eq >>> 2 ], \ >>> + "qidl PP $(*D)/$(*F).c"),) >>> +%.o: %.c %.qidl.c >>> + $(if $(strip $(shell test -f $(*D)/qidl-generated/$(*F).qidl.c && echo >>> "true")), \ >>> + $(call quiet-command, \ >>> + $(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c \ >>> + -DQIDL_ENABLED -include $< -o $@ >>> $(*D)/qidl-generated/$(*F).qidl.c, \ >>> + "qidl CC $@"), \ >>> + $(call quiet-command, \ >>> + $(CC) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c \ >>> + -o $@ $<," CC $@")) >> >> >> Because the .qidl.c files are not created for files without a QIDL_ENABLE() >> directive, all those files will be grepped on every invocation of the >> makefile. >> >> It is better to define the list of QIDL_ENABLEd files in an auxiliary >> makefile >> like this (untested): > > Thanks for the suggestion / example. > > FYI, I tried to get this working but didn't manage to get it in for v4. > Everything > seems to be falling back to the non-qidl %o: target, and I haven't had time to > debug it. > > FWIW, it doesn't seem to be a major factor performance-wise. Current build > times on my laptop are (for all-target builds): > > QIDL v4: > real 8m35.383s > user 31m1.844s > sys 1m33.998s > > upstream: > real 8m28.181s > user 30m44.983s > sys 1m29.926s
Isn't the more interesting case that I only touched block/qcow2.c and run make to update my binaries? I haven't really looked at the code, but Paolo's comment suggests that even in this case a lot of files would be grepped, and I think that losing a few seconds in such cases would really hurt. Kevin
