perf jevents: Run metric_test.py at compile-time

Add a target that generates a log file for running metric_test.py and
make this a dependency on generating pmu-events.c. The log output is
displayed if the test fails like (the test was modified to make it
fail):

```
  TEST    /tmp/perf/pmu-events/metric_test.log
F......
======================================================================
FAIL: test_Brackets (__main__.TestMetricExpressions)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "tools/perf/pmu-events/metric_test.py", line 33, in test_Brackets
    self.assertEqual((a * b + c).ToPerfJson(), 'a * b + d')
AssertionError: 'a * b + c' != 'a * b + d'
- a * b + c
?         ^
+ a * b + d
?         ^

----------------------------------------------------------------------
Ran 7 tests in 0.004s

FAILED (failures=1)
make[3]: *** [pmu-events/Build:32: /tmp/perf/pmu-events/metric_test.log] Error 1
```

However, normal execution will just show the TEST line.

This is roughly modeled on fortify testing in the kernel lib directory.

Modify metric_test.py so that it is executable. This is necessary when
PYTHON isn't specified in the build, the normal case.

Use variables to make the paths to files clearer and more consistent.

Committer notes:

Add pmu-events/metric_test.log to tools/perf/.gitignore and to the
'clean' target on tools/perf/Makefile.perf.

Reviewed-by: Kajol Jain <[email protected]>
Signed-off-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Caleb Biggers <[email protected]>
Cc: Florian Fischer <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jing Zhang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Kang Minchul <[email protected]>
Cc: Kim Phillips <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Perry Taylor <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Sandipan Das <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Xing Zhengjun <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

4 files changed, 14 insertions, 2 deletions

diff --git a/tools/perf/.gitignore b/tools/perf/.gitignore
index 05806ecfc33c..f533e76fb480 100644
--- a/tools/perf/.gitignore
+++ b/tools/perf/.gitignore
@@ -38,6 +38,7 @@ arch/*/include/generated/
 trace/beauty/generated/
 pmu-events/pmu-events.c
 pmu-events/jevents
+pmu-events/metric_test.log
 feature/
 libapi/
 libbpf/
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index b7d9c4206230..bac9272682b7 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -1103,6 +1103,7 @@ clean:: $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clean $(LIBSYMBOL)-clean $(
 		$(OUTPUT)util/intel-pt-decoder/inat-tables.c \
 		$(OUTPUT)tests/llvm-src-{base,kbuild,prologue,relocation}.c \
 		$(OUTPUT)pmu-events/pmu-events.c \
+		$(OUTPUT)pmu-events/metric_test.log \
 		$(OUTPUT)$(fadvise_advice_array) \
 		$(OUTPUT)$(fsconfig_arrays) \
 		$(OUTPUT)$(fsmount_arrays) \
diff --git a/tools/perf/pmu-events/Build b/tools/perf/pmu-events/Build
index a14de24ecb69..150765f2baee 100644
--- a/tools/perf/pmu-events/Build
+++ b/tools/perf/pmu-events/Build
@@ -6,6 +6,11 @@ JDIR_TEST	=  pmu-events/arch/test
 JSON_TEST	=  $(shell [ -d $(JDIR_TEST) ] &&			\
 			find $(JDIR_TEST) -name '*.json')
 JEVENTS_PY	=  pmu-events/jevents.py
+METRIC_PY	=  pmu-events/metric.py
+METRIC_TEST_PY	=  pmu-events/metric_test.py
+EMPTY_PMU_EVENTS_C = pmu-events/empty-pmu-events.c
+PMU_EVENTS_C	=  $(OUTPUT)pmu-events/pmu-events.c
+METRIC_TEST_LOG	=  $(OUTPUT)pmu-events/metric_test.log
 
 ifeq ($(JEVENTS_ARCH),)
 JEVENTS_ARCH=$(SRCARCH)
@@ -18,11 +23,15 @@ JEVENTS_MODEL ?= all
 #
 
 ifeq ($(NO_JEVENTS),1)
-$(OUTPUT)pmu-events/pmu-events.c: pmu-events/empty-pmu-events.c
+$(PMU_EVENTS_C): $(EMPTY_PMU_EVENTS_C)
 	$(call rule_mkdir)
 	$(Q)$(call echo-cmd,gen)cp $< $@
 else
-$(OUTPUT)pmu-events/pmu-events.c: $(JSON) $(JSON_TEST) $(JEVENTS_PY) pmu-events/metric.py
+$(METRIC_TEST_LOG): $(METRIC_TEST_PY) $(METRIC_PY)
+	$(call rule_mkdir)
+	$(Q)$(call echo-cmd,test)$(PYTHON) $< 2> $@ || (cat $@ && false)
+
+$(PMU_EVENTS_C): $(JSON) $(JSON_TEST) $(JEVENTS_PY) $(METRIC_PY) $(METRIC_TEST_LOG)
 	$(call rule_mkdir)
 	$(Q)$(call echo-cmd,gen)$(PYTHON) $(JEVENTS_PY) $(JEVENTS_ARCH) $(JEVENTS_MODEL) pmu-events/arch $@
 endif
diff --git a/tools/perf/pmu-events/metric_test.py b/tools/perf/pmu-events/metric_test.py
index e4c792428277..40a3c7d8b2bc 100644..100755
--- a/tools/perf/pmu-events/metric_test.py
+++ b/tools/perf/pmu-events/metric_test.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
 import unittest
 from metric import Constant