[strong] Implement revised strong class semantics

test/mjsunit/strong/class-literals.js

+// Copyright 2015 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: --strong-mode --allow-natives-syntax
+
+'use strict';
+
+function assertWeakClassWeakInstances(x) {
+  assertFalse(%IsStrong(x));
+  assertFalse(%IsStrong(x.prototype));
+  assertFalse(%IsStrong(new x));
+}
+
+function assertWeakClassStrongInstances(x) {
+  assertFalse(%IsStrong(x));
+  assertFalse(%IsStrong(x.prototype));
+  assertTrue(%IsStrong(new x));
+}
+
+function assertStrongClassWeakInstances(x) {
+  assertTrue(%IsStrong(x));
+  assertTrue(%IsStrong(x.prototype));
+  assertFalse(%IsStrong(new x));
+}
+
+function assertStrongClassStrongInstances(x) {
+  assertTrue(%IsStrong(x));
+  assertTrue(%IsStrong(x.prototype));
+  assertTrue(%IsStrong(new x));
+}
+
+function getWeakClass() {
+  return (class {});
+}
+
+function getWeakClassExtends(x) {
+  return (class extends x {});
+}
+
+function getStrongClass() {
+  "use strong";
+  return (class {});
+}
+
+function getStrongClassExtends(x) {
+  "use strong";
+  return (class extends x {});
+}
+
+(function SimpleWeakClassLiterals() {
+  class C {};
+  class D extends C {};
+  class E extends Object {};
+
+  assertWeakClassWeakInstances(C);
+  assertWeakClassWeakInstances(D);
+  assertWeakClassWeakInstances(E);
+
+  assertWeakClassWeakInstances(class {});
+  assertWeakClassWeakInstances(class extends Object {});
+  assertWeakClassWeakInstances(class extends C {});
+  assertWeakClassWeakInstances(class extends class {} {});
+})();
+
+(function SimpleStrongClassLiterals() {
+  'use strong';
+  class C {};
+  class D extends C {};
+
+  assertStrongClassStrongInstances(C);
+  assertStrongClassStrongInstances(D);
+
+  assertStrongClassStrongInstances(class {});
+  assertStrongClassStrongInstances(class extends C {});
+  assertStrongClassStrongInstances(class extends class {} {});
+})();
+
+(function MixedWeakClassLiterals() {
+  class C extends getStrongClass() {};
+  class D extends getStrongClassExtends((class {})) {};
+  class E extends getStrongClassExtends(C) {};
+
+  assertWeakClassStrongInstances(C);
+  assertWeakClassStrongInstances(class extends getStrongClass() {});
+
+  assertWeakClassWeakInstances(D);
+  assertWeakClassWeakInstances(
+    class extends getStrongClassExtends((class {})) {});
+
+  assertWeakClassStrongInstances(E);
+  assertWeakClassStrongInstances(
+    class extends getStrongClassExtends(class extends getStrongClass() {}) {});
+})();
+
+(function MixedStrongClassLiterals() {
+  'use strong';
+  class C extends getWeakClass() {};
+  class D extends getWeakClassExtends((class {})) {};
+  class E extends getWeakClassExtends(C) {};
+  class F extends Object {};
+
+  assertStrongClassWeakInstances(C);
+  assertStrongClassWeakInstances(class extends getWeakClass() {});
+
+  assertStrongClassStrongInstances(D);
+  assertStrongClassStrongInstances(
+    class extends getWeakClassExtends((class {})) {});
+
+  assertStrongClassWeakInstances(E);
+  assertStrongClassWeakInstances(
+    class extends getWeakClassExtends(class extends getWeakClass() {}) {});
+
+  assertStrongClassWeakInstances(F);
+  assertStrongClassWeakInstances(class extends Object {});
+})();
+
+(function WeakMonkeyPatchedClassLiterals() {
+  class C {};
+  assertWeakClassWeakInstances(C);
+  C.__proto__ = getStrongClass();
+  // C's default constructor doesn't call super.
+  assertWeakClassWeakInstances(C);
+
+  class D extends Object {};
+  assertWeakClassWeakInstances(D);
+  D.__proto__ = getStrongClass();
+  // D is a derived class, so its default constructor calls super.
+  assertWeakClassStrongInstances(D);
+
+  class E extends (class {}) {};
+  E.__proto__ = C;
+  assertWeakClassWeakInstances(E);
+
+  class F extends (class {}) {};
+  F.__proto__ = D;
+  assertWeakClassStrongInstances(F);
+
+  class G extends getStrongClass() {};
+  G.__proto__ = getWeakClass();
+  assertWeakClassWeakInstances(G);
+})();
+
+(function StrongMonkeyPatchedClassLiterals() {
+  let C = getStrongClassExtends(getWeakClassExtends(getStrongClass()));
+  let D = getStrongClassExtends(getWeakClassExtends(getWeakClass()));
+
+  assertStrongClassStrongInstances(C);
+  C.__proto__.__proto__ = getWeakClass();
+  assertStrongClassWeakInstances(C);
+  C.__proto__.__proto__ = getStrongClass();
+  assertStrongClassStrongInstances(C);
+
+  assertStrongClassWeakInstances(D);
+  D.__proto__.__proto__ = getStrongClass();
+  assertStrongClassStrongInstances(D);
+  D.__proto__.__proto__ = getWeakClass();
+  assertStrongClassWeakInstances(D);
+})();