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.
> # 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?
Thanks,
Ian
> --
> 2.41.0.487.g6d72f3e995-goog
>
