[tests] add microbenchmark for %TypedArray%.prototype.copyWithin

Add a simple microbenchmark for calling copyWithin on a moderately large
Float64Array with 10,000 elements.

BUG=v8:5925, v8:5929, v8:4648
R=cbruni@chromium.org, adamk@chromium.org, littledan@chromium.org

Review-Url: https://codereview.chromium.org/2676193002
Cr-Commit-Position: refs/heads/master@{#42944}

test/js-perf-test/JSTests.json

@@ -274,6 +274,18 @@
         {"name": "Object.hasOwnProperty--el-str"},
         {"name": "Object.hasOwnProperty--NE-el"}
       ]
+    },
+    {
+      "name": "TypedArrays",
+      "path": ["TypedArrays"],
+      "main": "run.js",
+      "resources": [
+        "typedarrays.js"
+      ],
+      "results_regexp": "^TypedArrays\\-%s\\(Scope\\): (.+)$",
+      "tests": [
+        {"name": "CopyWithin"}
+      ]
     }
   ]
 }

test/js-perf-test/TypedArrays/run.js

+// Copyright 2014 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('../base.js');
+load('typedarrays.js');
+
+
+var success = true;
+
+function PrintResult(name, result) {
+  print(`TypedArrays-${name}(Score): ${result}`);
+}
+
+
+function PrintError(name, error) {
+  PrintResult(name, error);
+  success = false;
+}
+
+
+BenchmarkSuite.config.doWarmup = undefined;
+BenchmarkSuite.config.doDeterministic = undefined;
+
+BenchmarkSuite.RunSuites({ NotifyResult: PrintResult,
+                           NotifyError: PrintError });

test/js-perf-test/TypedArrays/typedarrays.js

+// Copyright 2017 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.
+
+new BenchmarkSuite('CopyWithin', [1000], [
+  new Benchmark('CopyWithin-Large', false, false, 0,
+                CopyWithinLarge, CopyWithinLargeSetup, CopyWithinLargeTearDown),
+]);
+
+var initialLargeFloat64Array = new Array(10000);
+for (var i = 0; i < 5000; ++i) {
+  initialLargeFloat64Array[i] = i;
+}
+initialLargeFloat64Array = new Float64Array(initialLargeFloat64Array);
+var largeFloat64Array;
+
+function CopyWithinLarge() {
+  largeFloat64Array.copyWithin(5000);
+}
+
+function CopyWithinLargeSetup() {
+  largeFloat64Array = new Float64Array(initialLargeFloat64Array);
+}
+
+function CopyWithinLargeTearDown() {
+  for (var i = 0; i < 5000; ++i) {
+    if (largeFloat64Array[i + 5000] !== i) {
+      throw new TypeError("Unexpected result!\n" + largeFloat64Array);
+    }
+  }
+  largeFloat64Array = void 0;
+}