On Wed, Jul 26, 2023 at 3:57 PM Namhyung Kim namhyung@kernel.org wrote:
Hi Ian,
On Wed, Jul 26, 2023 at 8:48 AM Ian Rogers irogers@google.com wrote:
On Wed, Jul 26, 2023 at 6:36 AM Namhyung Kim namhyung@kernel.org 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@vger.kernel.org Signed-off-by: Namhyung Kim namhyung@kernel.org
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