[PATCH V3] tools/perf: Add perf binary dependent rule for shellcheck log in Makefile.perf

[Athira Rajeev]

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

Condition for shellcheck is added in Makefile.perf 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.

Example build failure with present scripts in tests/shell:

	INSTALL libsubcmd_headers
	INSTALL libperf_headers
	INSTALL libapi_headers
	INSTALL libsymbol_headers
	INSTALL libbpf_headers
	make[3]: *** [/root/athira/namhyung/perf-tools-next/tools/perf/tests/Makefile.tests:17: output/tests/shell/record_sideband.dep] Error 1
	make[3]: *** Waiting for unfinished jobs....
	make[3]: *** [/root/athira/namhyung/perf-tools-next/tools/perf/tests/Makefile.tests:17: output/tests/shell/test_arm_coresight.dep] Error 1
	make[3]: *** [/root/athira/namhyung/perf-tools-next/tools/perf/tests/Makefile.tests:17: output/tests/shell/lock_contention.dep] Error 1
	make[2]: *** [Makefile.perf:675: SHELLCHECK_TEST] Error 2
	make[1]: *** [Makefile.perf:238: sub-make] Error 2
	make: *** [Makefile:70: all] Error 2

After this, for testing, changed "tests/shell/record.sh" to
break shellcheck format. In the next make run, it is
also captured:

	make[3]: *** [/root/athira/namhyung/perf-tools-next/tools/perf/tests/Makefile.tests:17: output/tests/shell/record_sideband.dep] Error 1
	make[3]: *** Waiting for unfinished jobs....
	make[3]: *** [/root/athira/namhyung/perf-tools-next/tools/perf/tests/Makefile.tests:17: output/tests/shell/record.dep] Error 1
	make[3]: *** [/root/athira/namhyung/perf-tools-next/tools/perf/tests/Makefile.tests:17: output/tests/shell/test_arm_coresight.dep] Error 1
	make[3]: *** [/root/athira/namhyung/perf-tools-next/tools/perf/tests/Makefile.tests:17: output/tests/shell/lock_contention.dep] Error 1
	make[2]: *** [Makefile.perf:675: SHELLCHECK_TEST] Error 2
	make[1]: *** [Makefile.perf:238: sub-make] Error 2
	make: *** [Makefile:70: all] Error 2

The exact failure log can be found in:
output/tests/shell/record.dep.log file

This is reported at build time. To be able to go ahead with
the build or disable shellcheck even though it is known that
some test is broken, add a "NO_SHELLCHECK" option. Example:

  make NO_LIBTRACEEVENT=1 NO_SHELLCHECK=1

  INSTALL libsubcmd_headers
  INSTALL libsymbol_headers
  INSTALL libperf_headers
  INSTALL libapi_headers
  INSTALL libbpf_headers
  PERF_VERSION = 6.6.rc1.g7108a40e02ae
  GEN     perf-iostat
  GEN     perf-archive
  CC      util/header.o
  LD      util/perf-in.o
  LD      perf-in.o
  LINK    perf

Signed-off-by: Athira Rajeev <atrajeev at linux.vnet.ibm.com>
---
changelog:
 v2 -> v3:
 Add option "NO_SHELLCHECK". This will allow to go ahead
 with the build or disable shellcheck even though it is
 known that some test is broken

 v1 -> v2:
 Version1 had shellcheck in feature check which is not
 required since shellcheck is already a binary. Presence
 of binary can be checked using:
 $(shell command -v shellcheck)
 Addressed these changes as suggested by Namhyung in V2
 Feature test logic is removed in V2. Also added example
 for build breakage when shellcheck fails in commit message

 tools/perf/Makefile.perf        | 20 +++++++++++++++++++-
 tools/perf/tests/Makefile.tests | 24 ++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 tools/perf/tests/Makefile.tests

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 456872ac410d..bb49eb8b0d43 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -134,6 +134,8 @@ include ../scripts/utilities.mak
 #	x86 instruction decoder - new instructions test
 #
 # Define GEN_VMLINUX_H to generate vmlinux.h from the BTF.
+#
+# Define NO_SHELLCHECK if you do not want to run shellcheck during build
 
 # As per kernel Makefile, avoid funny character set dependencies
 unexport LC_ALL
@@ -671,7 +673,22 @@ $(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
+
+SHELLCHECK := $(shell command -v shellcheck)
+ifeq ($(NO_SHELLCHECK),1)
+SHELLCHECK :=
+endif
+
+ifneq ($(SHELLCHECK),)
+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 $@
 
@@ -1134,6 +1151,7 @@ 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..8011e99768a3
--- /dev/null
+++ b/tools/perf/tests/Makefile.tests
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: GPL-2.0
+# Athira Rajeev <atrajeev at linux.vnet.ibm.com>, 2023
+
+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)
+	$(eval input_file := $(subst output/,./,$(patsubst %.dep, %.sh, $@)))
+	$(Q)$(call frecho-cmd,test)@shellcheck -S warning ${input_file} 1> $@.log && ([[ ! -s $@.log ]])
+	$(Q)$(call frecho-cmd,test)@touch $@
+	$(Q)$(call frecho-cmd,test)@rm -rf $@.log
+$(DIRS):
+	@mkdir -p $@
+
+clean:
+	@rm -rf output
-- 
2.31.1