Add js-perf-test benchmark for generators.

test/js-perf-test/Generators/generators.js

+// Copyright 2016 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('Generators', [1000], [
+  new Benchmark('Basic', false, false, 0, Basic),
+  new Benchmark('Loop', false, false, 0, Loop),
+  new Benchmark('Input', false, false, 0, Input),
+  new Benchmark('YieldStar', false, false, 0, YieldStar),
+]);
+
+
+// ----------------------------------------------------------------------------
+// Benchmark: Basic
+// ----------------------------------------------------------------------------
+
+function* five() {
+  yield 1;
+  yield 2;
+  yield 3;
+  yield 4;
+  yield 5;
+}
+
+function Basic() {
+  let g = five();
+  let sum = 0;
+  sum += g.next().value;
+  sum += g.next().value;
+  sum += g.next().value;
+  sum += g.next().value;
+  sum += g.next().value;
+  if (sum != 15 || !g.next().done) throw "wrong";
+}
+
+
+// ----------------------------------------------------------------------------
+// Benchmark: Loop
+// ----------------------------------------------------------------------------
+
+function* fibonacci() {
+  let x = 0;
+  let y = 1;
+  yield x;
+  while (true) {
+    yield y;
+    let tmp = x;
+    x = y;
+    y += tmp;
+  }
+}
+
+function Loop() {
+  let n = 0;
+  let x;
+  for (x of fibonacci()) {
+    if (++n === 42) break;
+  }
+  if (x != 165580141) throw "wrong";
+}
+
+
+
+// ----------------------------------------------------------------------------
+// Benchmark: Input
+// ----------------------------------------------------------------------------
+
+function* multiples(x) {
+  let skip = function.sent || 0;
+  let next = 0;
+  while (true) {
+    if (skip === 0) {
+      skip = yield next;
+    } else {
+      skip--;
+    }
+    next += x;
+  }
+}
+
+function Input() {
+  let g = multiples(3);
+  results = [g.next(2), g.next(0), g.next(5), g.next(10)];
+  if (results.slice(-1)[0].value != 60) throw "wrong";
+}
+
+
+// ----------------------------------------------------------------------------
+// Benchmark: YieldStar
+// ----------------------------------------------------------------------------
+
+function* infix(node) {
+  if (node) {
+    yield* infix(node.left);
+    yield node.label;
+    yield* infix(node.right);
+  }
+}
+
+class Node {
+  constructor(label, left, right) {
+    this.label = label;
+    this.left = left;
+    this.right = right;
+  }
+}
+
+function YieldStar() {
+  let tree = new Node(1,
+      new Node(2,
+          new Node(3,
+              new Node(4,
+                  new Node(16,
+                      new Node(5,
+                          new Node(23,
+                              new Node(0),
+                              new Node(17)),
+                          new Node(44, new Node(20)))),
+                  new Node(7,
+                      undefined,
+                      new Node(23,
+                          new Node(0),
+                          new Node(41, undefined, new Node(11))))),
+              new Node(8)),
+          new Node(5)),
+      new Node(6, undefined, new Node(7)));
+  let labels = [...(infix(tree))];
+  // 0,23,17,5,20,44,16,4,7,0,23,41,11,3,8,2,5,1,6,7
+  if (labels[0] != 0) throw "wrong";
+}