On Mon, Oct 15, 2012 at 10:52:37AM +0200, Kevin Wolf wrote: > 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.
True, that's the more interesting case and I missed that point in my response (had actually thought Paolo was driving at making qemu-idl-files.mak a top-level target to avoid re-grepping on each --target-list entry's build) But Paolo posted some clarification in the v4 comments for this patch on why this isn't the case for individual compilation units. The re-grep would only occur for cases where the .c file changes, or something else that might affect the output of the code generators changed (scripts/(qidl|qapi)*, qidl.h, etc.). So in your example only block/qcow2.c would be re-grepped. > > Kevin >