[array] Add megamorphic Array.p.sort benchmark

This CL adds a benchmark where the array to sort undergoes
multiple element kind transitions before it is sorted.

R=jgruber@chromium.org

Bug: v8:7382
Change-Id: I5196a33139a5f3b833719c2a111dc9a521bdb37c
Reviewed-on: https://chromium-review.googlesource.com/1066012
Commit-Queue: Simon Zünd <szuend@google.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53283}

test/js-perf-test/ArraySort/sort-base.js

@@ -124,3 +124,5 @@ function cmp_smaller(a, b) {
   if (b < a) return 1;
   return 0;
 }
+
+function cmp_greater(a, b) { return cmp_smaller(b, a); }

test/js-perf-test/ArraySort/sort-cmpfn.js

@@ -4,8 +4,6 @@
 
 load('sort-base.js');
 
-function cmp_greater(a, b) { return cmp_smaller(b, a); }
-
 // Each benchmark calls sort with multiple different comparison functions
 // to create polyomorphic call sites. Most/all of the
 // other sort benchmarks have monomorphic call sites.

test/js-perf-test/ArraySort/sort-megamorphic.js

+// Copyright 2018 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+load('sort-base.js');
+
+function SetupMegamorphic() {
+  CreatePackedSmiArray();
+
+  Array.prototype.sort.call([1.1]);
+  Array.prototype.sort.call(['a']);
+  Array.prototype.sort.call([2,,3]);
+  Array.prototype.sort.call([0.2,,0.1]);
+  Array.prototype.sort.call(['b',,'a']);
+  Array.prototype.sort.call({});
+}
+
+benchy('Base', Sort, SetupMegamorphic);
+benchy('MultipleCompareFns', CreateSortFn([cmp_smaller, cmp_greater]),
+       SetupMegamorphic);

test/js-perf-test/JSTests.json

@@ -775,6 +775,21 @@
         {"name": "PackedSmiPreSortedReversed"}
       ]
     },
+    {
+      "name": "ArraySortMegamorphic",
+      "path": ["ArraySort"],
+      "main": "run.js",
+      "resources": ["sort-base.js", "sort-megamorphic.js"],
+      "test_flags": ["sort-megamorphic"],
+      "results_regexp": "^%s\\-ArraySort\\(Score\\): (.+)$",
+      "flags": [
+        "--allow-natives-syntax"
+      ],
+      "tests": [
+        {"name": "Base"},
+        {"name": "MultipleCompareFns"}
+      ]
+    },
     {
       "name": "ForLoops",
       "path": ["ForLoops"],