[test-suite][AIX] Enable profiling via hpmcount on AIX

[lkail]

Summary

Add --param=profile=hpmcount option to lit thus support profiling via hpmcount on AIX.

Each test will run under hpmcount and output data of hpmcount will be stored in Output directory. It's best run it after bindprocessor and use -j1.

[lkail]

Ping

[jsji]

LGTM, please hold a few days in case some comments from other reviewers. Thanks.

lit.cfg

 # Pass on some options to context object:
 config.perf_profile_events = "cycles,cache-misses,branch-misses,instructions"
 if lit_config.params.get('perf_profile_events'):
     config.perf_profile_events = lit_config.params.get('perf_profile_events')
 
 # Find and initialize lit modules.
 if lit_config.params.get('profile') == 'perf':
     config.test_modules += ['perf']
+
+if lit_config.params.get('profile') == 'hpmcount':
+    config.test_modules += ['hpmcount']

litsupport/modules/hpmcount.py

+"""Test Module to perform an extra execution of the benchmark in the AIX
+hpmcount tool."""
+from litsupport import shellcommand
+from litsupport import testplan
+from litsupport.modules import run_under
+
+import os
+
+
+def _mutateCommandLine(context, commandline):
+    context.profilefile = context.tmpBase + ".hpmcount_data"
+    # Storing profile file in context allows other modules to be aware of it.
+    cmd = shellcommand.parse(commandline)
+    cmd.wrap('hpmcount', ['-o', context.profilefile])
+    if cmd.stdout is None:
+        cmd.stdout = os.devnull
+    else:
+        cmd.stdout += ".hpmcount"
+    if cmd.stderr is None:
+        cmd.stderr = os.devnull
+    else:
+        cmd.stderr += ".hpmcount"
+    return cmd.toCommandline()
+
+
+def mutatePlan(context, plan):
+    script = context.parsed_runscript
+    if context.config.run_under:
+        script = testplan.mutateScript(context, script,
+                                       run_under.mutateCommandLine)
+    script = testplan.mutateScript(context, script, _mutateCommandLine)
+    plan.profilescript += script
+    plan.metric_collectors.append(
+        lambda context: {'profile': context.profilefile})