Reland "[test] Keep the order of variants"

This is a reland of 8f4407fb.

Original change's description:
> [test] Keep the order of variants
> 
> Bug: v8:6917
> Change-Id: I7e04255649f62a28f0ed07ccb4fbaf4825498bf6
> Reviewed-on: https://chromium-review.googlesource.com/886841
> Commit-Queue: Michał Majewski <majeski@google.com>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#50874}

Bug: v8:6917
Change-Id: I9d4c617ccec6db8929af3095f2f27d8964c5d6b8
Reviewed-on: https://chromium-review.googlesource.com/888582Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michał Majewski <majeski@google.com>
Cr-Commit-Position: refs/heads/master@{#50901}

test/message/testcfg.py

@@ -58,13 +58,6 @@ class TestSuite(testsuite.TestSuite):
   def _test_class(self):
     return TestCase
 
-  def CreateLegacyVariantsGenerator(self, variants):
-    return super(TestSuite, self).CreateLegacyVariantsGenerator(
-        variants + ["preparser"])
-
-  def create_variant_proc(self, variants):
-    return super(TestSuite, self).create_variant_proc(variants + ['preparser'])
-
 
 class TestCase(testcase.TestCase):
   def __init__(self, *args, **kwargs):

tools/testrunner/local/testsuite.py

@@ -43,7 +43,7 @@ STANDARD_VARIANT = set(["default"])
 class LegacyVariantsGenerator(object):
   def __init__(self, suite, variants):
     self.suite = suite
-    self.all_variants = ALL_VARIANTS & variants
+    self.all_variants = variants
     self.standard_variant = STANDARD_VARIANT & variants
 
   def FilterVariantsByTest(self, test):

tools/testrunner/local/variants.py

@@ -25,4 +25,27 @@ ALL_VARIANT_FLAGS = {
   "wasm_traps": [["--wasm_trap_handler", "--invoke-weak-callbacks", "--wasm-jit-to-native"]],
 }
 
-ALL_VARIANTS = set(ALL_VARIANT_FLAGS.keys())
+SLOW_VARIANTS = set([
+  'stress',
+  'nooptimization',
+])
+
+FAST_VARIANTS = set([
+  'default'
+])
+
+
+def _variant_order_key(v):
+  if v in SLOW_VARIANTS:
+    return 0
+  if v in FAST_VARIANTS:
+    return 100
+  return 50
+
+ALL_VARIANTS = sorted(ALL_VARIANT_FLAGS.keys(),
+                      key=_variant_order_key)
+
+# Check {SLOW,FAST}_VARIANTS entries
+for variants in [SLOW_VARIANTS, FAST_VARIANTS]:
+  for v in variants:
+    assert v in ALL_VARIANT_FLAGS

tools/testrunner/standard_runner.py

@@ -39,14 +39,13 @@ from testrunner.testproc.variant import VariantProc
 
 TIMEOUT_DEFAULT = 60
 
-# Variants ordered by expected runtime (slowest first).
 VARIANTS = ["default"]
 
 MORE_VARIANTS = [
-  "stress",
-  "stress_incremental_marking",
   "nooptimization",
+  "stress",
   "stress_background_compile",
+  "stress_incremental_marking",
   "wasm_traps",
 ]
 
@@ -112,6 +111,7 @@ class StandardTestRunner(base_runner.BaseTestRunner):
         super(StandardTestRunner, self).__init__(*args, **kwargs)
 
         self.sancov_dir = None
+        self._variants = None
 
     def _get_default_suite_names(self):
       return ['default']
@@ -249,8 +249,6 @@ class StandardTestRunner(base_runner.BaseTestRunner):
       return False
 
     def _process_options(self, options):
-      global VARIANTS
-
       if options.sancov_dir:
         self.sancov_dir = options.sancov_dir
         if not os.path.exists(self.sancov_dir):
@@ -315,9 +313,6 @@ class StandardTestRunner(base_runner.BaseTestRunner):
       if options.random_seed_stress_count <= 1 and options.random_seed == 0:
         options.random_seed = self._random_seed()
 
-      # Use developer defaults if no variant was specified.
-      options.variants = options.variants or "dev"
-
       if options.variants == "infra_staging":
         options.variants = "exhaustive"
         options.infra_staging = True
@@ -325,18 +320,7 @@ class StandardTestRunner(base_runner.BaseTestRunner):
       # Use staging on whitelisted masters/builders.
       options.infra_staging = self._use_staging(options)
 
-      # Resolve variant aliases and dedupe.
-      # TODO(machenbach): Don't mutate global variable. Rather pass mutated
-      # version as local variable.
-      VARIANTS = list(set(reduce(
-          list.__add__,
-          (VARIANT_ALIASES.get(v, [v]) for v in options.variants.split(",")),
-          [],
-      )))
-
-      if not set(VARIANTS).issubset(ALL_VARIANTS):
-        print "All variants must be in %s" % str(ALL_VARIANTS)
-        raise base_runner.TestRunnerError()
+      self._variants = self._parse_variants(options.variants)
 
       def CheckTestMode(name, option):  # pragma: no cover
         if not option in ["run", "skip", "dontcare"]:
@@ -350,6 +334,23 @@ class StandardTestRunner(base_runner.BaseTestRunner):
         # TODO(machenbach): uncomment after infra side lands.
         # base_runner.TEST_MAP["d8_default"].remove("intl")
 
+    def _parse_variants(self, aliases_str):
+      # Use developer defaults if no variant was specified.
+      aliases_str = aliases_str or 'dev'
+      aliases = aliases_str.split(',')
+      user_variants = set(reduce(
+          list.__add__, [VARIANT_ALIASES.get(a, [a]) for a in aliases]))
+
+      result = [v for v in ALL_VARIANTS if v in user_variants]
+      if len(result) == len(user_variants):
+        return result
+
+      for v in user_variants:
+        if v not in ALL_VARIANTS:
+          print 'Unknown variant: %s' % v
+          raise base_runner.TestRunnerError()
+      assert False, 'Unreachable'
+
     def _setup_env(self):
       super(StandardTestRunner, self)._setup_env()
 
@@ -481,7 +482,7 @@ class StandardTestRunner(base_runner.BaseTestRunner):
         if options.cat:
           verbose.PrintTestSource(s.tests)
           continue
-        variant_gen = s.CreateLegacyVariantsGenerator(VARIANTS)
+        variant_gen = s.CreateLegacyVariantsGenerator(self._variants)
         variant_tests = [ t.create_variant(v, flags)
                           for t in s.tests
                           for v in variant_gen.FilterVariantsByTest(t)
@@ -597,7 +598,7 @@ class StandardTestRunner(base_runner.BaseTestRunner):
         StatusFileFilterProc(options.slow_tests, options.pass_fail_tests),
         self._create_shard_proc(options),
         tests_counter,
-        VariantProc(VARIANTS),
+        VariantProc(self._variants),
         StatusFileFilterProc(options.slow_tests, options.pass_fail_tests),
       ] + indicators + [
         results,