[TypeFeedbackVector] Root feedback vectors at function literal site.

test/mjsunit/strong-rooted-literals.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.
+
+// Flags: --allow-natives-syntax --expose-gc --turbo
+
+// Make sure literals are strongly rooted and safe from weak-code deopts.
+
+(function() {
+  function foo() {
+    var a = {y: 0};
+    a.y = 1;
+    return a;
+  }
+
+  foo();
+  foo();
+  % OptimizeFunctionOnNextCall(foo);
+  foo();
+  gc();
+  assertOptimized(foo);
+})();
+
+(function() {
+  function hot(o) {
+    return o.x + o.y;
+  }
+  function mapPlus(a, y) {
+    return a.map(x => hot({x, y}));
+  }
+
+  var a = [1, 2, 3];
+  print(mapPlus(a, 1));
+  print(mapPlus(a, 2));
+  % OptimizeFunctionOnNextCall(hot);
+  print(mapPlus(a, 3));
+  gc();  // BOOOM!
+  assertOptimized(hot);
+  print(mapPlus(a, 4));
+})();
+
+// Verify that we can handle the creation of a new script, where the
+// code is cached and the feedback vector has to be re-created.
+(function() {
+  var sopen = 'function wrapper() {  ';
+  var s1 = 'function foo() { return bar(5); } ';
+  var s2 = 'foo(); foo(); %OptimizeFunctionOnNextCall(foo); foo(); ';
+  var sclose = '}  wrapper(); ';
+  var s = sopen + s1 + s2 + sclose;
+  function bar(i){return i + 3};
+
+  for (var i = 0; i < 4; i++) {
+    eval(s);
+  }
+})();