[PATCH v5 15/15] perf jevents: Run metric_test.py at compile-time

[Ian Rogers]

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.
---
 tools/perf/pmu-events/Build          | 13 +++++++++++--
 tools/perf/pmu-events/metric_test.py |  1 +
 2 files changed, 12 insertions(+), 2 deletions(-)
 mode change 100644 => 100755 tools/perf/pmu-events/metric_test.py

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
old mode 100644
new mode 100755
index e4c792428277..40a3c7d8b2bc
--- 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
-- 
2.39.1.456.gfc5497dd1b-goog