perf jevents: Handle deleted JSONS in out of source builds

Make the source folders a dependency for the generated folder root so
that whenever a file is deleted from the source it will force a new
fresh copy of all the JSON files and avoid stale deleted files.

JSON_DIRS_OUTPUT_ROOT needs to be a dependency of LEGACY_CACHE_JSON so
that the root folder doesn't get cleaned after the legacy JSON is
generated. But this is a no-op with in-source builds as
JSON_DIRS_OUTPUT_ROOT is unset.

JSON_DIRS is added as a dependency of PMU_EVENTS_C which also forces a
re-build for in source builds when JSON files are deleted. This could
have also resulted in stale builds, but never a broken one.

Closes: https://lore.kernel.org/linux-next/aW5XSAo88_LBPSYI@sirena.org.uk/
Fixes: 4bb55de4ff03db3e ("perf jevents: Support copying the source json files to OUTPUT")
Reported-by: Mark Brown <broonie@kernel.org>
Signed-off-by: James Clark <james.clark@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/pmu-events/Build b/tools/perf/pmu-events/Build
index a46ab7b612dfc2c23c05b4d8d517bed6bf8b00ab..4f9ef624ba70d33aacff7031346db8ce1128a98a 100644 (file)
--- a/tools/perf/pmu-events/Build
+++ b/tools/perf/pmu-events/Build
@@ -1,5 +1,6 @@
 pmu-events-y   += pmu-events.o
 JSON           =  $(shell find pmu-events/arch -name '*.json' -o -name '*.csv')
+JSON_DIRS      =  $(shell find pmu-events/arch -type d)
 JDIR_TEST      =  pmu-events/arch/test
 JSON_TEST      =  $(shell [ -d $(JDIR_TEST) ] &&                       \
                        find $(JDIR_TEST) -name '*.json')
@@ -31,16 +32,23 @@ $(PMU_EVENTS_C): $(EMPTY_PMU_EVENTS_C)
 else
 # Copy checked-in json to OUTPUT for generation if it's an out of source build
 ifneq ($(OUTPUT),)
-$(OUTPUT)pmu-events/arch/%: pmu-events/arch/%
+# Remove all output directories when any source directory timestamp changes
+# so there are no stale deleted files
+JSON_DIRS_ROOT = $(OUTPUT)pmu-events/arch/
+$(JSON_DIRS_ROOT): $(JSON_DIRS)
+       $(Q)$(call echo-cmd,gen)rm -rf $@
+       $(Q)mkdir -p $@
+
+$(OUTPUT)pmu-events/arch/%: pmu-events/arch/% $(JSON_DIRS_ROOT)
        $(call rule_mkdir)
        $(Q)$(call echo-cmd,gen)cp $< $@
 endif
 
-$(LEGACY_CACHE_JSON): $(LEGACY_CACHE_PY)
+$(LEGACY_CACHE_JSON): $(LEGACY_CACHE_PY) $(JSON_DIRS_ROOT)
        $(call rule_mkdir)
        $(Q)$(call echo-cmd,gen)$(PYTHON) $(LEGACY_CACHE_PY) > $@
 
-GEN_JSON = $(patsubst %,$(OUTPUT)%,$(JSON)) $(LEGACY_CACHE_JSON)
+GEN_JSON = $(patsubst %,$(OUTPUT)%,$(JSON)) $(LEGACY_CACHE_JSON) $(JSON_DIRS)
 
 $(METRIC_TEST_LOG): $(METRIC_TEST_PY) $(METRIC_PY)
        $(call rule_mkdir)