On Wed, Jul 26, 2023 at 3:57 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote: > > Hi Ian, > > On Wed, Jul 26, 2023 at 8:48 AM Ian Rogers <irogers@xxxxxxxxxx> wrote: > > > > On Wed, Jul 26, 2023 at 6:36 AM Namhyung Kim <namhyung@xxxxxxxxxx> wrote: > > > > > > The bison and flex generate C files from the source (.y and .l) > > > files. When O= option is used, they are saved in a separate directory > > > but the default build rule assumes the .C files are in the source > > > directory. So it might read invalid file if there are generated files > > > from an old version. The same is true for the pmu-events files. > > > > > > For example, the following command would cause a build failure: > > > > > > $ git checkout v6.3 > > > $ make -C tools/perf # build in the same directory > > > > > > $ git checkout v6.5-rc2 > > > $ mkdir build # create a build directory > > > $ make -C tools/perf O=build # build in a different directory but it > > > # refers files in the source directory > > > > > > Let's update the build rule to specify those cases explicitly to depend > > > on the files in the output directory. > > > > > > Note that it's not a complete fix and it needs the next patch for the > > > include path too. > > > > > > Fixes: 80eeb67fe577 ("perf jevents: Program to convert JSON file") > > > Cc: stable@xxxxxxxxxxxxxxx > > > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx> > > > --- > > > tools/build/Makefile.build | 8 ++++++++ > > > tools/perf/pmu-events/Build | 4 ++++ > > > 2 files changed, 12 insertions(+) > > > > > > diff --git a/tools/build/Makefile.build b/tools/build/Makefile.build > > > index 89430338a3d9..f9396696fcbf 100644 > > > --- a/tools/build/Makefile.build > > > +++ b/tools/build/Makefile.build > > > @@ -117,6 +117,14 @@ $(OUTPUT)%.s: %.c FORCE > > > $(call rule_mkdir) > > > $(call if_changed_dep,cc_s_c) > > > > > > +$(OUTPUT)%-bison.o: $(OUTPUT)%-bison.c FORCE > > > + $(call rule_mkdir) > > > + $(call if_changed_dep,$(host)cc_o_c) > > > + > > > +$(OUTPUT)%-flex.o: $(OUTPUT)%-flex.c FORCE > > > + $(call rule_mkdir) > > > + $(call if_changed_dep,$(host)cc_o_c) > > > + > > > > Hi Namhyung, > > > > as we have: > > ``` > > $(OUTPUT)%.o: %.c FORCE > > $(call rule_mkdir) > > $(call if_changed_dep,$(host)cc_o_c) > > ``` > > I'm not sure what the 2 additional rules achieve. > > The above rule assumes the .c files are in the source directory > (without $(OUTPUT) prefix). It caused a trouble when the > flex and bison files are generated in the output directory and > you have an old version of them in the source directory. > > > > > > > # Gather build data: > > > # obj-y - list of build objects > > > # subdir-y - list of directories to nest > > > diff --git a/tools/perf/pmu-events/Build b/tools/perf/pmu-events/Build > > > index 150765f2baee..f38a27765604 100644 > > > --- a/tools/perf/pmu-events/Build > > > +++ b/tools/perf/pmu-events/Build > > > @@ -35,3 +35,7 @@ $(PMU_EVENTS_C): $(JSON) $(JSON_TEST) $(JEVENTS_PY) $(METRIC_PY) $(METRIC_TEST_L > > > $(call rule_mkdir) > > > $(Q)$(call echo-cmd,gen)$(PYTHON) $(JEVENTS_PY) $(JEVENTS_ARCH) $(JEVENTS_MODEL) pmu-events/arch $@ > > > endif > > > + > > > +$(OUTPUT)pmu-events/pmu-events.o: $(PMU_EVENTS_C) > > > + $(call rule_mkdir) > > > + $(call if_changed_dep,$(host)cc_o_c) > > > > If we add this, do the Makefile.build changes still need to happen? > > The Makefile.build changes are specific to flex and bison files. > So yes, we need this for pmu-events.c to work properly with O= > option. Got it, you are right I was confusing the flex/bison with the jevents case. Can we get away with a single rule then: ``` $(OUTPUT)%.o: $(OUTPUT)%.c FORCE $(call rule_mkdir) $(call if_changed_dep,$(host)cc_o_c) ``` Thanks, Ian > Thanks, > Namhyung