Il 24/01/2013 16:50, Stefan Hajnoczi ha scritto: > Generated trace event code is written to trace/generated-tracers.c. The > 'dtrace' backend does not generate C code, instead the dtrace(1) utility > takes a .dtrace file as input and produces a .o file as output. > > Therefore, with 'dtrace' we have: > generated-tracers.o <- generated-tracers.dtrace > > Without 'dtrace' we have: > generated-tracers.o <- generated-tracers.c > > When QEMU is built with ./configure --enable-trace-backend=simple > followed by ./configure --enable-trace-backend=dtrace, the > generated-tracers.c file remains although the 'dtrace' backend does not > use it. > > Because the %.o: %.c target is defined before the %.o: %.dtrace target > in rules.mak, we'll actually pull in the stale .c file instead of using > the .dtrace file! The resulting build is a mix of 'dtrace' and 'simple' > trace backends - and it fails loudly. > > Commit 0e848f482bce75f4d9cbac9f495fa45e51d08c9a (build: some > simplifications for "trace/Makefile.objs") changed trace/Makefile.objs > so that 'dtrace' and non-'dtrace' builds use generated-tracers.o. > Previously we used generated-tracers-dtrace.o for 'dtrace' builds only > and generated-tracers.o for non-'dtrace' builds only. > > This patch is somewhat ugly. It undoes the change from > 0e848f482bce75f4d9cbac9f495fa45e51d08c9a so that the 'dtrace' and > non-'dtrace' builds do not conflict with each other. > > The result is that 'dtrace' builds no longer fail if stale > generated-tracers.c files are present. > > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> > --- > Can someone think of a better way to fix this?
Doesn't really look ugly. Thanks for fixing this. Paolo > Perhaps we've really outgrown in-tree builds and need to switch to a ./build/ > directory that can be blown away each time ./configure runs (fingers crossed > you have ccache installed or the build may take some time). > > rules.mak | 2 +- > trace/Makefile.objs | 5 +++-- > 2 files changed, 4 insertions(+), 3 deletions(-) > > diff --git a/rules.mak b/rules.mak > index 6d82c0d..d8b0672 100644 > --- a/rules.mak > +++ b/rules.mak > @@ -29,7 +29,7 @@ else > LIBTOOL += $(if $(V),,--quiet) > %.lo: %.c > $(call quiet-command,$(LIBTOOL) --mode=compile --tag=CC $(CC) > $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<," lt > CC $@") > -%.lo: %.dtrace > +%-dtrace.lo: %.dtrace > $(call quiet-command,$(LIBTOOL) --mode=compile --tag=CC dtrace -o $@ -G > -s $<, " lt GEN $(TARGET_DIR)$@") > > LINK = $(call quiet-command,\ > diff --git a/trace/Makefile.objs b/trace/Makefile.objs > index 27fe26b..97e280d 100644 > --- a/trace/Makefile.objs > +++ b/trace/Makefile.objs > @@ -24,6 +24,7 @@ $(obj)/generated-tracers.c-timestamp: > $(SRC_PATH)/trace-events $(BUILD_DIR)/conf > @cmp -s $@ $(patsubst %-timestamp,%,$@) || cp $@ $(patsubst > %-timestamp,%,$@) > > $(obj)/generated-tracers.o: $(obj)/generated-tracers.c > $(obj)/generated-tracers.h > +util-obj-y += generated-tracers.o > endif > > > @@ -45,7 +46,8 @@ $(obj)/generated-tracers.dtrace-timestamp: > $(SRC_PATH)/trace-events $(BUILD_DIR) > $(obj)/generated-tracers-dtrace.h: $(obj)/generated-tracers.dtrace > $(call quiet-command,dtrace -o $@ -h -s $<, " GEN $@") > > -$(obj)/generated-tracers.o: $(obj)/generated-tracers.dtrace > +$(obj)/generated-tracers-dtrace.o: $(obj)/generated-tracers.dtrace > +util-obj-y += generated-tracers-dtrace.o > endif > > ###################################################################### > @@ -55,4 +57,3 @@ util-obj-$(CONFIG_TRACE_DEFAULT) += default.o > util-obj-$(CONFIG_TRACE_SIMPLE) += simple.o > util-obj-$(CONFIG_TRACE_STDERR) += stderr.o > util-obj-y += control.o > -util-obj-y += generated-tracers.o >
