Reland "Simplify static initializer test"

This reverts commit 239e5b82.

> The old sizes.py perf test used to check for a whole set of performance
> regressions. This is now handled elsewhere with the exception of the SI
> check. The SI check is fairly simple, however, and doesn't require all
> of the the perf_expectations infrastructure which is now obsolete.
>
> This CL removes the obsolete perf_expectations, hard codes the expected
> number of SIs in the script, and removes the windows and android code
> as it doesn't actually do anything.
>
> Bug: 572393

CQ_INCLUDE_TRYBOTS=luci.chromium.try:linux_chromium_archive_rel_ng;luci.chromium.try:mac_chromium_archive_rel_ng;luci.chromium.try:win_archive;luci.chromium.try:win_x64_archive;master.tryserver.chromium.android:android_archive_rel_ng
TBR=dpranke

Bug: 572393
Change-Id: Iad25e02aba593632f167bb534be95ba6a5691446
Reviewed-on: https://chromium-review.googlesource.com/1241935Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594389}

docs/static_initializers.md

@@ -9,7 +9,7 @@ http://neugierig.org/software/chromium/notes/2011/08/static-initializers.html
 # How Static Initializers are Checked
 
 * For Linux and Mac:
-  * The expected count is stored in [//tools/perf_expectations/perf_expectations.json](https://cs.chromium.org/chromium/src/tools/perf_expectations/perf_expectations.json)
+  * The expected count is stored in [//infra/scripts/legacy/scripts/slave/chromium/sizes.py](https://cs.chromium.org/chromium/src/infra/scripts/legacy/scripts/slave/chromium/sizes.py)
 * For Android:
   * The expected count is stored in the build target [//chrome/android:monochrome_static_initializers](https://cs.chromium.org/chromium/src/chrome/android/BUILD.gn)
 

testing/scripts/sizes.py

@@ -50,45 +50,13 @@ def main_run(script_args):
       sizes_cmd.extend(['--platform', args.platform])
     rc = common.run_runtest(script_args, runtest_args + sizes_cmd)
     with open(tempfile_path) as f:
-      results = json.load(f)
-
-  with open(os.path.join(common.SRC_DIR, 'tools', 'perf_expectations',
-                         'perf_expectations.json')) as f:
-    perf_expectations = json.load(f)
-
-  valid = (rc == 0)
-  failures = []
-
-  for name, result in results.iteritems():
-    fqtn = '%s/%s/%s' % (args.prefix, name, result['identifier'])
-    if fqtn not in perf_expectations:
-      continue
-
-    if perf_expectations[fqtn]['type'] != 'absolute':
-      print 'ERROR: perf expectation %r is not yet supported' % fqtn
-      valid = False
-      continue
-
-    actual = result['value']
-    expected = perf_expectations[fqtn]['regress']
-    better = perf_expectations[fqtn]['better']
-    check_result = ((actual <= expected) if better == 'lower'
-                    else (actual >= expected))
-
-    if not check_result:
-      failures.append(fqtn)
-      print 'FAILED %s: actual %s, expected %s, better %s' % (
-          fqtn, actual, expected, better)
+      failures = json.load(f)
 
   json.dump({
-      'valid': valid,
+      'valid': rc == 0,
       'failures': failures,
   }, script_args.output)
 
-  # sizes.py itself doesn't fail on regressions.
-  if failures and rc == 0:
-    rc = 1
-
   return rc
 
 

tools/linux/dump-static-initializers.py

@@ -38,8 +38,10 @@ NOTES = {
 IS_GIT_WORKSPACE = (subprocess.Popen(
     ['git', 'rev-parse'], stderr=subprocess.PIPE).wait() == 0)
 
+
 class Demangler(object):
   """A wrapper around c++filt to provide a function to demangle symbols."""
+
   def __init__(self, toolchain):
     self.cppfilt = subprocess.Popen([toolchain + 'c++filt'],
                                     stdin=subprocess.PIPE,
@@ -50,6 +52,7 @@ class Demangler(object):
     self.cppfilt.stdin.write(sym + '\n')
     return self.cppfilt.stdout.readline().strip()
 
+
 # Matches for example: "cert_logger.pb.cc", capturing "cert_logger".
 protobuf_filename_re = re.compile(r'(.*)\.pb\.cc$')
 def QualifyFilenameAsProto(filename):
@@ -72,6 +75,7 @@ def QualifyFilenameAsProto(filename):
     candidate = line.strip()
   return candidate
 
+
 # Regex matching the substring of a symbol's demangled text representation most
 # likely to appear in a source file.
 # Example: "v8::internal::Builtins::InitBuiltinFunctionTable()" becomes
@@ -99,6 +103,7 @@ def QualifyFilename(filename, symbol):
     candidate = line.strip()
   return candidate
 
+
 # Regex matching nm output for the symbols we're interested in.
 # See test_ParseNmLine for examples.
 nm_re = re.compile(r'(\S+) (\S+) t (?:_ZN12)?_GLOBAL__(?:sub_)?I_(.*)')
@@ -123,6 +128,7 @@ def test_ParseNmLine():
     '_GLOBAL__sub_I_extension_specifics.pb.cc')
   assert parse == ('extension_specifics.pb.cc', 40607408, 36), parse
 
+
 # Just always run the test; it is fast enough.
 test_ParseNmLine()
 
@@ -136,6 +142,7 @@ def ParseNm(toolchain, binary):
     if parse:
       yield parse
 
+
 # Regex matching objdump output for the symbols we're interested in.
 # Example line:
 #     12354ab:  (disassembly, including <FunctionReference>)
@@ -158,13 +165,14 @@ def ExtractSymbolReferences(toolchain, binary, start, end):
       if ref.startswith('.LC') or ref.startswith('_DYNAMIC'):
         # Ignore these, they are uninformative.
         continue
-      if ref.startswith('_GLOBAL__I_'):
+      if re.match('_GLOBAL__(?:sub_)?I_', ref):
         # Probably a relative jump within this function.
         continue
       refs.add(ref)
 
   return sorted(refs)
 
+
 def main():
   parser = optparse.OptionParser(usage='%prog [option] filename')
   parser.add_option('-d', '--diffable', dest='diffable',
@@ -236,5 +244,6 @@ def main():
 
   return 0
 
+
 if '__main__' == __name__:
   sys.exit(main())

tools/perf_expectations/OWNERS

-jochen@chromium.org
-thakis@chromium.org
-thestig@chromium.org

tools/perf_expectations/PRESUBMIT.py

-# Copyright (c) 2011 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-"""Presubmit script for perf_expectations.
-
-See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts for
-details on the presubmit API built into depot_tools.
-"""
-
-PERF_EXPECTATIONS = 'tools/perf_expectations/perf_expectations.json'
-CONFIG_FILE = 'tools/perf_expectations/chromium_perf_expectations.cfg'
-
-def CheckChangeOnUpload(input_api, output_api):
-  run_tests = False
-  for path in input_api.LocalPaths():
-    path = path.replace('\\', '/')
-    if (PERF_EXPECTATIONS == path or CONFIG_FILE == path):
-      run_tests = True
-
-  output = []
-  if run_tests:
-    whitelist = [r'.+_unittest\.py$']
-    output.extend(input_api.canned_checks.RunUnitTestsInDirectory(
-        input_api, output_api, 'tests', whitelist))
-  return output
-
-
-def CheckChangeOnCommit(input_api, output_api):
-  run_tests = False
-  for path in input_api.LocalPaths():
-    path = path.replace('\\', '/')
-    if (PERF_EXPECTATIONS == path or CONFIG_FILE == path):
-      run_tests = True
-
-  output = []
-  if run_tests:
-    whitelist = [r'.+_unittest\.py$']
-    output.extend(input_api.canned_checks.RunUnitTestsInDirectory(
-        input_api, output_api, 'tests', whitelist))
-
-  output.extend(input_api.canned_checks.CheckDoNotSubmit(input_api,
-                                                         output_api))
-  return output

tools/perf_expectations/README.txt

-This is where old perf machinery used to live, keeping track of binary sizes,
-etc. Now that lives elsewhere and has a team to support it (see
-https://www.chromium.org/developers/tree-sheriffs/perf-sheriffs). This code
-remains to ensure that no static initializers get into Chromium.
-
-Because this code has this history, it's far more complicated than it needs to
-be. TODO(dpranke): Simplify it. https://crbug.com/572393
-
-In the meanwhile, if you're trying to update perf_expectations.json, there are
-no instructions for doing so, and the tools that you used to use don't work
-because they rely on data files that were last updated at the end of 2015. So
-here's what to do to reset the expected static initializer count value.
-
-The expected static initializer count value is in the "regress" field for the
-platform. In addition, each platform has a checksum in the "sha1" field to
-ensure that you properly used the magic tools. Since the magic tools don't work
-anymore, dpranke added a bypass to the verification. If you run:
-
-> tools/perf_expectations/make_expectations.py --checksum --verbose
-
-the script will tell you what the checksum *should* be. Alter the "sha1" field
-to be that value, and you can commit changes to that file.
-
-Please see https://crbug.com/572393 for more information.

tools/perf_expectations/chromium_perf_expectations.cfg

-{
-  "base_url": "http://build.chromium.org/f/chromium/perf",
-  "perf_file": "perf_expectations.json"
-}

tools/perf_expectations/perf_expectations.json

-{"linux-release-64/sizes/chrome-si/initializers": {"reva": 480969, "revb": 480969, "type": "absolute", "better": "lower", "improve": 8, "regress": 8, "tolerance": 0, "sha1": "3c815259"},
- "linux-release-64/sizes/nacl_helper-si/initializers": {"reva": 480969, "revb": 480969, "type": "absolute", "better": "lower", "improve": 6, "regress": 8, "sha1": "8416f450"},
- "linux-release-64/sizes/nacl_helper_bootstrap-si/initializers": {"reva": 114822, "revb": 115019, "type": "absolute", "better": "lower", "improve": 0, "regress": 0, "sha1": "228221af"},
- "linux-release/sizes/chrome-si/initializers": {"reva": 480969, "revb": 480969, "type": "absolute", "better": "lower", "improve": 9, "regress": 9, "tolerance": 0, "sha1": "03dc3cfd"},
- "linux-release/sizes/nacl_helper-si/initializers": {"reva": 480969, "revb": 480969, "type": "absolute", "better": "lower", "improve": 7, "regress": 9, "sha1": "1a3c5b2b"},
- "linux-release/sizes/nacl_helper_bootstrap-si/initializers": {"reva": 114822, "revb": 115019, "type": "absolute", "better": "lower", "improve": 0, "regress": 0, "sha1": "dd908f29"},
- "mac-release/sizes/chrome-si/initializers": {"reva": 281731, "revb": 281731, "type": "absolute", "better": "lower", "improve": 0, "regress": 0, "tolerance": 0, "sha1": "01759b7f"},
- "load": true
-}

tools/perf_expectations/sample_test_cases.json

-{"linux-release/media_tests_av_perf/audio_latency/latency": {"reva": 180005, "revb": 180520, "type": "absolute", "better": "lower", "improve": 190, "regress": 222, "sha1": "fc9815d5"},
-"linux-release/media_tests_av_perf/dropped_fps/tulip2.wav": {"reva": 181131, "revb": 181572, "type": "absolute", "better": "lower", "improve": 0, "regress": 0, "sha1": "fb8157f9"},
-"linux-release/media_tests_av_perf/dropped_fps/tulip2.webm": {"reva": 181131, "revb": 181572, "type": "absolute", "better": "lower", "improve": 0, "regress": 0, "sha1": "c0fb3421"},
-"linux-release/media_tests_av_perf/dropped_frames/crowd1080.webm": {"reva": 181131, "revb": 181572, "type": "absolute", "better": "lower", "improve": 0, "regress": 0, "sha1": "fa9582d3"},
-"linux-release/media_tests_av_perf/dropped_frames/crowd2160.webm": {"reva": 181131, "revb": 181572, "type": "absolute", "better": "lower", "improve": 166, "regress": 231, "sha1": "ca3a7a47"},
-"linux-release/media_tests_av_perf/fps/tulip2.m4a": {"reva": 34239, "revb": 1298213, "type": "absolute", "better": "higher", "improve": 0, "regress": 0},
-"linux-release/media_tests_av_perf/fps/tulip2.mp3": {"reva": 34239, "revb": 1298213, "type": "absolute", "better": "higher", "improve": 0, "regress": 0},
-"linux-release/media_tests_av_perf/fps/tulip2.mp4": {"reva": 34239, "revb": 1298213, "type": "absolute", "better": "higher", "improve": 32, "regress": 28},
-"linux-release/media_tests_av_perf/fps/tulip2.ogg": {"reva": 34239, "revb": 1298213, "type": "absolute", "better": "higher", "improve": 0, "regress": 0},
-"linux-release/media_tests_av_perf/fps/tulip2.ogv": {"reva": 34239, "revb": 1298213, "type": "absolute", "better": "higher", "improve": 32, "regress": 28},
-"linux-release/media_tests_av_perf/fps/tulip2.wav": {"reva": 34239, "revb": 1298213, "type": "absolute", "better": "higher", "improve": 0, "regress": 0},
-"win-release/media_tests_av_perf/dropped_fps/tulip2.wav": {"reva": 181131, "revb": 181572, "type": "absolute", "better": "lower", "improve": 0, "regress": 0, "sha1": "646c02f2"},
-"win-release/media_tests_av_perf/dropped_fps/tulip2.webm": {"reva": 181131, "revb": 181572, "type": "absolute", "better": "lower", "improve": 0, "regress": 0, "sha1": "46c97b57"},
-"win-release/media_tests_av_perf/dropped_frames/crowd1080.webm": {"reva": 181131, "revb": 181572, "type": "absolute", "better": "lower", "improve": 0, "regress": 0, "sha1": "9b709aab"},
-"win-release/media_tests_av_perf/dropped_frames/crowd2160.webm": {"reva": 181131, "revb": 181572, "type": "absolute", "better": "lower", "improve": 174, "regress": 204, "sha1": "4c0270a6"},
-"win-release/media_tests_av_perf/fps/crowd1080.webm": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 53, "regress": 43, "sha1": "7ad49461"},
-"win-release/media_tests_av_perf/fps/crowd2160.webm": {"reva": 176330, "revb": 176978, "type": "absolute", "better": "higher", "improve": 26.0399945997, "regress": 25.9062437562, "sha1": "700526a9"},
-"win-release/media_tests_av_perf/fps/crowd360.webm": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 51, "regress": 47, "sha1": "7f8ef21c"},
-"win-release/media_tests_av_perf/fps/crowd480.webm": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 50, "regress": 47, "sha1": "5dc96881"},
-"win-release/media_tests_av_perf/fps/crowd720.webm": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 52, "regress": 47, "sha1": "4fcfb653"},
-"win-release/media_tests_av_perf/fps/tulip2.m4a": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 0, "regress": 0, "sha1": "54d94538"},
-"win-release/media_tests_av_perf/fps/tulip2.mp3": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 0, "regress": 0, "sha1": "113aef17"},
-"win-release/media_tests_av_perf/fps/tulip2.mp4": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 30, "regress": 28, "sha1": "a22847d0"},
-"win-release/media_tests_av_perf/fps/tulip2.ogg": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 0, "regress": 0, "sha1": "6ee2e716"},
-"win-release/media_tests_av_perf/fps/tulip2.ogv": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 32, "regress": 26, "sha1": "dfadb872"},
-"win-release/media_tests_av_perf/fps/tulip2.wav": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 0, "regress": 0, "sha1": "530c5bf5"},
-"win-release/media_tests_av_perf/fps/tulip2.webm": {"reva": 163299, "revb": 164141, "type": "absolute", "better": "higher", "improve": 30, "regress": 28, "sha1": "35b91c8e"}
-}
\ No newline at end of file

tools/perf_expectations/tests/perf_expectations_unittest.py

-#!/usr/bin/env python
-# Copyright (c) 2012 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-"""Verify perf_expectations.json can be loaded using simplejson.
-
-perf_expectations.json is a JSON-formatted file.  This script verifies
-that simplejson can load it correctly.  It should catch most common
-formatting problems.
-"""
-
-import subprocess
-import sys
-import os
-import unittest
-import re
-
-simplejson = None
-
-def OnTestsLoad():
-  old_path = sys.path
-  script_path = os.path.dirname(sys.argv[0])
-  load_path = None
-  global simplejson
-
-  # This test script should be stored in src/tools/perf_expectations/.  That
-  # directory will most commonly live in 2 locations:
-  #
-  #   - a regular Chromium checkout, in which case src/third_party
-  #     is where to look for simplejson
-  #
-  #   - a buildbot checkout, in which case .../pylibs is where
-  #     to look for simplejson
-  #
-  # Locate and install the correct path based on what we can find.
-  #
-  for path in ('../../../third_party', '../../../../../pylibs'):
-    path = os.path.join(script_path, path)
-    if os.path.exists(path) and os.path.isdir(path):
-      load_path = os.path.abspath(path)
-      break
-
-  if load_path is None:
-    msg = "%s expects to live within a Chromium checkout" % sys.argv[0]
-    raise Exception, "Error locating simplejson load path (%s)" % msg
-
-  # Try importing simplejson once.  If this succeeds, we found it and will
-  # load it again later properly.  Fail if we cannot load it.
-  sys.path.append(load_path)
-  try:
-    import simplejson as Simplejson
-    simplejson = Simplejson
-  except ImportError, e:
-    msg = "%s expects to live within a Chromium checkout" % sys.argv[0]
-    raise Exception, "Error trying to import simplejson from %s (%s)" % \
-                     (load_path, msg)
-  finally:
-    sys.path = old_path
-  return True
-
-def LoadJsonFile(filename):
-  f = open(filename, 'r')
-  try:
-    data = simplejson.load(f)
-  except ValueError, e:
-    f.seek(0)
-    print "Error reading %s:\n%s" % (filename,
-                                     f.read()[:50]+'...')
-    raise e
-  f.close()
-  return data
-
-OnTestsLoad()
-
-CONFIG_JSON = os.path.join(os.path.dirname(sys.argv[0]),
-                           '../chromium_perf_expectations.cfg')
-MAKE_EXPECTATIONS = os.path.join(os.path.dirname(sys.argv[0]),
-                                 '../make_expectations.py')
-PERF_EXPECTATIONS = os.path.join(os.path.dirname(sys.argv[0]),
-                                 '../perf_expectations.json')
-
-
-class PerfExpectationsUnittest(unittest.TestCase):
-  def testPerfExpectations(self):
-    # Test data is dictionary.
-    perf_data = LoadJsonFile(PERF_EXPECTATIONS)
-    if not isinstance(perf_data, dict):
-      raise Exception('perf expectations is not a dict')
-
-    # Test the 'load' key.
-    if not 'load' in perf_data:
-      raise Exception("perf expectations is missing a load key")
-    if not isinstance(perf_data['load'], bool):
-      raise Exception("perf expectations load key has non-bool value")
-
-    # Test all key values are dictionaries.
-    bad_keys = []
-    for key in perf_data:
-      if key == 'load':
-        continue
-      if not isinstance(perf_data[key], dict):
-        bad_keys.append(key)
-    if len(bad_keys) > 0:
-      msg = "perf expectations keys have non-dict values"
-      raise Exception("%s: %s" % (msg, bad_keys))
-
-    # Test all key values have delta and var keys.
-    for key in perf_data:
-      if key == 'load':
-        continue
-
-      # First check if regress/improve is in the key's data.
-      if 'regress' in perf_data[key]:
-        if 'improve' not in perf_data[key]:
-          bad_keys.append(key)
-        if (not isinstance(perf_data[key]['regress'], int) and
-            not isinstance(perf_data[key]['regress'], float)):
-          bad_keys.append(key)
-        if (not isinstance(perf_data[key]['improve'], int) and
-            not isinstance(perf_data[key]['improve'], float)):
-          bad_keys.append(key)
-      else:
-        # Otherwise check if delta/var is in the key's data.
-        if 'delta' not in perf_data[key] or 'var' not in perf_data[key]:
-          bad_keys.append(key)
-        if (not isinstance(perf_data[key]['delta'], int) and
-            not isinstance(perf_data[key]['delta'], float)):
-          bad_keys.append(key)
-        if (not isinstance(perf_data[key]['var'], int) and
-            not isinstance(perf_data[key]['var'], float)):
-          bad_keys.append(key)
-
-    if len(bad_keys) > 0:
-      msg = "perf expectations key values missing or invalid delta/var"
-      raise Exception("%s: %s" % (msg, bad_keys))
-
-    # Test all keys have the correct format.
-    for key in perf_data:
-      if key == 'load':
-        continue
-      # tools/buildbot/scripts/master/log_parser.py should have a matching
-      # regular expression.
-      if not re.match(r"^([\w\.-]+)/([\w\.-]+)/([\w\.-]+)/([\w\.-]+)$", key):
-        bad_keys.append(key)
-    if len(bad_keys) > 0:
-      msg = "perf expectations keys in bad format, expected a/b/c/d"
-      raise Exception("%s: %s" % (msg, bad_keys))
-
-  def testNoUpdatesNeeded(self):
-    p = subprocess.Popen([MAKE_EXPECTATIONS, '-s'], stdout=subprocess.PIPE)
-    p.wait();
-    self.assertEqual(p.returncode, 0,
-        msg='Update expectations first by running ./make_expectations.py')
-
-  def testConfigFile(self):
-    # Test that the config file can be parsed as JSON.
-    config = LoadJsonFile(CONFIG_JSON)
-    # Require the following keys.
-    if 'base_url' not in config:
-      raise Exception('base_url not specified in config file')
-    if 'perf_file' not in config:
-      raise Exception('perf_file not specified in config file')
-
-
-if __name__ == '__main__':
-  unittest.main()

tools/perf_expectations/update_perf_expectations.py

-#!/usr/bin/env python
-# Copyright (c) 2013 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-"""Prepare tests that require re-baselining for input to make_expectations.py.
-
-The regularly running perf-AV tests require re-baselineing of expectations
-about once a week. The steps involved in rebaselining are:
-
-1.) Identify the tests to update, based off reported e-mail results.
-2.) Figure out reva and revb values, which is the starting and ending revision
- numbers for the range that we should use to obtain new thresholds.
-3.) Modify lines in perf_expectations.json referring to the tests to be updated,
- so that they may be used as input to make_expectations.py.
-
-This script automates the last step above.
-
-Here's a sample line from perf_expectations.json:
-
-"win-release/media_tests_av_perf/fps/tulip2.m4a": {"reva": 163299, \
-"revb": 164141, "type": "absolute", "better": "higher", "improve": 0, \
-"regress": 0, "sha1": "54d94538"},
-
-To get the above test ready for input to make_expectations.py, it should become:
-
-"win-release/media_tests_av_perf/fps/tulip2.m4a": {"reva": <new reva>, \
-"revb": <new revb>, "type": "absolute", "better": "higher", "improve": 0, \
-"regress": 0},
-
-Examples:
-
-1.) To update the test specified above and get baseline
-values using the revision range 12345 and 23456, run this script with a command
-line like this:
-  python update_perf_expectations.py -f \
-  win-release/media_tests_av_perf/fps/tulip2.m4a --reva 12345 --revb 23456
-Or, using an input file,
-where the input file contains a single line with text
-  win-release/media_tests_av_perf/fps/tulip2.m4a
-run with this command line:
-  python update_perf_expectations.py -i input.txt --reva 12345 --revb 23456
-
-2.) Let's say you want to update all seek tests on windows, and get baseline
-values using the revision range 12345 and 23456.
-Run this script with this command line:
-  python update_perf_expectations.py -f win-release/media_tests_av_perf/seek/ \
-   --reva 12345 --revb 23456
-Or:
-  python update_perf_expectations.py -f win-release/.*/seek/ --reva 12345 \
-  --revb 23456
-
-Or, using an input file,
-where the input file contains a single line with text win-release/.*/seek/:
-  python update_perf_expectations.py -i input.txt --reva 12345 --revb 23456
-
-3.) Similarly, if you want to update seek tests on all platforms
-  python update_perf_expectations.py -f .*-release/.*/seek/ --reva 12345 \
-  --revb 23456
-
-"""
-
-import logging
-from optparse import OptionParser
-import os
-import re
-
-import make_expectations as perf_ex_lib
-
-# Default logging is INFO. Use --verbose to enable DEBUG logging.
-_DEFAULT_LOG_LEVEL = logging.INFO
-
-
-def GetTestsToUpdate(contents, all_test_keys):
-  """Parses input contents and obtains tests to be re-baselined.
-
-  Args:
-    contents: string containing contents of input file.
-    all_test_keys: list of keys of test dictionary.
-  Returns:
-    A list of keys for tests that should be updated.
-  """
-  # Each line of the input file specifies a test case to update.
-  tests_list = []
-  for test_case_filter in contents.splitlines():
-    # Skip any empty lines.
-    if test_case_filter:
-      # Sample expected line:
-      # win-release/media_tests_av_perf/seek/\
-      # CACHED_BUFFERED_SEEK_NoConstraints_crowd1080.ogv
-      # Or, if reg-ex, then sample line:
-      # win-release/media-tests_av_perf/seek*
-      # Skip any leading spaces if they exist in the input file.
-      logging.debug('Trying to match %s', test_case_filter)
-      tests_list.extend(GetMatchingTests(test_case_filter.strip(),
-                                         all_test_keys))
-  return tests_list
-
-
-def GetMatchingTests(tests_to_update, all_test_keys):
-  """Parses input reg-ex filter and obtains tests to be re-baselined.
-
-  Args:
-    tests_to_update: reg-ex string specifying tests to be updated.
-    all_test_keys: list of keys of tests dictionary.
-  Returns:
-    A list of keys for tests that should be updated.
-  """
-  tests_list = []
-  search_string = re.compile(tests_to_update)
-  # Get matching tests from the dictionary of tests
-  for test_key in all_test_keys:
-    if search_string.match(test_key):
-      tests_list.append(test_key)
-      logging.debug('%s will be updated', test_key)
-  logging.info('%s tests found matching reg-ex: %s', len(tests_list),
-               tests_to_update)
-  return tests_list
-
-
-def PrepareTestsForUpdate(tests_to_update, all_tests, reva, revb):
-  """Modifies value of tests that are to re-baselined:
-     Set reva and revb values to specified new values. Remove sha1.
-
-  Args:
-    tests_to_update: list of tests to be updated.
-    all_tests: dictionary of all tests.
-    reva: oldest revision in range to use for new values.
-    revb: newest revision in range to use for new values.
-  Raises:
-    ValueError: If reva or revb are not valid ints, or if either
-    of them are negative.
-  """
-  reva = int(reva)
-  revb = int(revb)
-
-  if reva < 0 or revb < 0:
-    raise ValueError('Revision values should be positive.')
-  # Ensure reva is less than revb.
-  # (this is similar to the check done in make_expectations.py)
-  if revb < reva:
-    temp = revb
-    revb = reva
-    reva = temp
-  for test_key in tests_to_update:
-    # Get original test from the dictionary of tests
-    test_value = all_tests[test_key]
-    if test_value:
-      # Sample line in perf_expectations.json:
-      #  "linux-release/media_tests _av_perf/dropped_frames/crowd360.webm":\
-      # {"reva": 155180, "revb": 155280, "type": "absolute", \
-      # "better": "lower", "improve": 0, "regress": 3, "sha1": "276ba29c"},
-      # Set new revision range
-      test_value['reva'] = reva
-      test_value['revb'] = revb
-      # Remove sha1 to indicate this test requires an update
-      # Check first to make sure it exist.
-      if 'sha1' in test_value:
-        del test_value['sha1']
-    else:
-      logging.warning('%s does not exist.', test_key)
-  logging.info('Done preparing tests for update.')
-
-
-def GetCommandLineOptions():
-  """Parse command line arguments.
-
-  Returns:
-    An options object containing command line arguments and their values.
-  """
-  parser = OptionParser()
-
-  parser.add_option('--reva', dest='reva', type='int',
-                    help='Starting revision of new range.',
-                    metavar='START_REVISION')
-  parser.add_option('--revb', dest='revb', type='int',
-                    help='Ending revision of new range.',
-                    metavar='END_REVISION')
-  parser.add_option('-f', dest='tests_filter',
-                    help='Regex to use for filtering tests to be updated. '
-                    'At least one of -filter or -input_file must be provided. '
-                    'If both are provided, then input-file is used.',
-                    metavar='FILTER', default='')
-  parser.add_option('-i', dest='input_file',
-                    help='Optional path to file with reg-exes for tests to'
-                    ' update. If provided, it overrides the filter argument.',
-                    metavar='INPUT_FILE', default='')
-  parser.add_option('--config', dest='config_file',
-                    default=perf_ex_lib.DEFAULT_CONFIG_FILE,
-                    help='Set the config file to FILE.', metavar='FILE')
-  parser.add_option('-v', dest='verbose', action='store_true', default=False,
-                    help='Enable verbose output.')
-  options = parser.parse_args()[0]
-  return options
-
-
-def Main():
-  """Main driver function."""
-  options = GetCommandLineOptions()
-
-  _SetLogger(options.verbose)
-  # Do some command-line validation
-  if not options.input_file and not options.tests_filter:
-    logging.error('At least one of input-file or test-filter must be provided.')
-    exit(1)
-  if options.input_file and options.tests_filter:
-    logging.error('Specify only one of input file or test-filter.')
-    exit(1)
-  if not options.reva or not options.revb:
-    logging.error('Start and end revision of range must be specified.')
-    exit(1)
-
-  # Load config.
-  config = perf_ex_lib.ConvertJsonIntoDict(
-      perf_ex_lib.ReadFile(options.config_file))
-
-  # Obtain the perf expectations file from the config file.
-  perf_file = os.path.join(
-      os.path.dirname(options.config_file), config['perf_file'])
-
-  # We should have all the information we require now.
-  # On to the real thang.
-  # First, get all the existing tests from the original perf_expectations file.
-  all_tests = perf_ex_lib.ConvertJsonIntoDict(
-      perf_ex_lib.ReadFile(perf_file))
-  all_test_keys = all_tests.keys()
-  # Remove the load key, because we don't want to modify it.
-  all_test_keys.remove('load')
-  # Keep tests sorted, like in the original file.
-  all_test_keys.sort()
-
-  # Next, get all tests that have been identified for an update.
-  tests_to_update = []
-  if options.input_file:
-    # Tests to update have been specified in an input_file.
-    # Get contents of file.
-    tests_filter = perf_ex_lib.ReadFile(options.input_file)
-  elif options.tests_filter:
-    # Tests to update have been specified as a reg-ex filter.
-    tests_filter = options.tests_filter
-
-  # Get tests to update based on filter specified.
-  tests_to_update = GetTestsToUpdate(tests_filter, all_test_keys)
-  logging.info('Done obtaining matching tests.')
-
-  # Now, prepare tests for update.
-  PrepareTestsForUpdate(tests_to_update, all_tests, options.reva, options.revb)
-
-  # Finally, write modified tests back to perf_expectations file.
-  perf_ex_lib.WriteJson(perf_file, all_tests, all_test_keys,
-                        calculate_sha1=False)
-  logging.info('Done writing tests for update to %s.', perf_file)
-
-
-def _SetLogger(verbose):
-  log_level = _DEFAULT_LOG_LEVEL
-  if verbose:
-    log_level = logging.DEBUG
-  logging.basicConfig(level=log_level, format='%(message)s')
-
-
-if __name__ == '__main__':
-  Main()