[PATCH 2/2] tools/perf: Add perf binary dependent rule for shellcheck log in Makefile.perf

[Athira Rajeev <atrajeev@linux.vnet.ibm.com>]

Add rule in new Makefile "tests/Makefile.tests" for running
shellcheck on shell test scripts. This automates below shellcheck
into the build.

	$ for F in $(find tests/shell/ -perm -o=x -name '*.sh'); do shellcheck -S warning $F; done

CONFIG_SHELLCHECK check is added to avoid build breakage in
the absence of shellcheck binary. Update Makefile.perf to contain
new rule for "SHELLCHECK_TEST" which is for making shellcheck
test as a dependency on perf binary. Added "tests/Makefile.tests"
to run shellcheck on shellscripts in tests/shell. The make rule
"SHLLCHECK_RUN" ensures that, every time during make, shellcheck
will be run only on modified files during subsequent invocations.
By this, if any newly added shell scripts or fixes in existing
scripts breaks coding/formatting style, it will get captured
during the perf build.

Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
---
 tools/perf/Makefile.perf        | 12 +++++++++++-
 tools/perf/tests/Makefile.tests | 24 ++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 tools/perf/tests/Makefile.tests

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index f6fdc2d5a92f..c27f54771e90 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -667,7 +667,16 @@ $(PERF_IN): prepare FORCE
 $(PMU_EVENTS_IN): FORCE prepare
 	$(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=pmu-events obj=pmu-events
 
-$(OUTPUT)perf: $(PERFLIBS) $(PERF_IN) $(PMU_EVENTS_IN)
+# Runs shellcheck on perf test shell scripts
+ifeq ($(CONFIG_SHELLCHECK),y)
+SHELLCHECK_TEST: FORCE prepare
+	$(Q)$(MAKE) -f $(srctree)/tools/perf/tests/Makefile.tests
+else
+SHELLCHECK_TEST:
+	@:
+endif
+
+$(OUTPUT)perf: $(PERFLIBS) $(PERF_IN) $(PMU_EVENTS_IN) SHELLCHECK_TEST
 	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) \
 		$(PERF_IN) $(PMU_EVENTS_IN) $(LIBS) -o $@
 
@@ -1129,6 +1138,7 @@ bpf-skel-clean:
 	$(call QUIET_CLEAN, bpf-skel) $(RM) -r $(SKEL_TMP_OUT) $(SKELETONS)
 
 clean:: $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clean $(LIBSYMBOL)-clean $(LIBPERF)-clean fixdep-clean python-clean bpf-skel-clean tests-coresight-targets-clean
+	$(Q)$(MAKE) -f $(srctree)/tools/perf/tests/Makefile.tests clean
 	$(call QUIET_CLEAN, core-objs)  $(RM) $(LIBPERF_A) $(OUTPUT)perf-archive $(OUTPUT)perf-iostat $(LANG_BINDINGS)
 	$(Q)find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
 	$(Q)$(RM) $(OUTPUT).config-detected
diff --git a/tools/perf/tests/Makefile.tests b/tools/perf/tests/Makefile.tests
new file mode 100644
index 000000000000..e74575559e83
--- /dev/null
+++ b/tools/perf/tests/Makefile.tests
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: GPL-2.0
+# Athira Rajeev <atrajeev@linux.vnet.ibm.com>, 2023
+-include $(OUTPUT).config-detected
+
+log_file = $(OUTPUT)shellcheck_test.log
+PROGS = $(subst ./,,$(shell find tests/shell -perm -o=x -type f -name '*.sh'))
+DEPS = $(addprefix output/,$(addsuffix .dep,$(basename $(PROGS))))
+DIRS = $(shell echo $(dir $(DEPS)) | xargs -n1 | sort -u | xargs)
+
+.PHONY: all
+all: SHELLCHECK_RUN
+	@:
+
+SHELLCHECK_RUN: $(DEPS) $(DIRS)
+
+output/%.dep: %.sh | $(DIRS)
+	$(call rule_mkdir)
+	$(Q)$(call frecho-cmd,test)@touch $@
+	$(Q)$(call frecho-cmd,test)@shellcheck -S warning $(subst output/,./,$(patsubst %.dep, %.sh, $@)) 1> ${log_file} && ([[ ! -s ${log_file} ]])
+$(DIRS):
+	@mkdir -p $@
+
+clean:
+	@rm -rf $(log_file) output
-- 
2.31.1