tor-browser

The Tor Browser
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getelem-getter-megamorphic.js (2159B)

      1 // Test for inlined getters for jsop_getelem accesses, where the getter is a
      2 // property on the prototype and a megamorphic IC is attached.
      3 
      4 function makeObjects(name) {
      5    class Base {
      6        constructor(v) {
      7            this._prop = v;
      8        }
      9        get [name]() {
     10            return this._prop;
     11        }
     12    }
     13 
     14    // When we hit |TYPE_FLAG_OBJECT_COUNT_LIMIT|, the objects are marked as
     15    // |TYPE_FLAG_ANYOBJECT|. That means less than |TYPE_FLAG_OBJECT_COUNT_LIMIT|
     16    // objects need to be created to have no unknown objects in the type set.
     17    const TYPE_FLAG_OBJECT_COUNT_LIMIT = 7;
     18 
     19    // |ICState::ICState::MaxOptimizedStubs| defines the maximum number of
     20    // optimized stubs, so as soon as we hit the maximum number, the megamorphic
     21    // state is entered.
     22    const ICState_MaxOptimizedStubs = 6;
     23 
     24    // Create enough classes to enter megamorphic state, but not too much to
     25    // have |TYPE_FLAG_ANYOBJECT| in the TypeSet.
     26    const OBJECT_COUNT = Math.min(ICState_MaxOptimizedStubs, TYPE_FLAG_OBJECT_COUNT_LIMIT);
     27 
     28    var objects = [];
     29    for (var i = 0; i < OBJECT_COUNT; ++i) {
     30        objects.push(new class extends Base {}(1));
     31    }
     32 
     33    return objects;
     34 }
     35 
     36 // Defined outside of the test functions to ensure they're recognised as
     37 // constants in Ion.
     38 var atom = "prop";
     39 var symbol = Symbol();
     40 
     41 function testAtom() {
     42    var objects = makeObjects(atom);
     43 
     44    function f() {
     45        var actual = 0;
     46        var expected = 0;
     47        for (var i = 0; i < 1000; i++) {
     48            var obj = objects[i % objects.length];
     49            actual += obj[atom];
     50            expected += obj._prop;
     51        }
     52        assertEq(actual, expected);
     53    }
     54 
     55    for (var i = 0; i < 2; ++i) {
     56        f();
     57    }
     58 }
     59 testAtom();
     60 
     61 function testSymbol() {
     62    var objects = makeObjects(symbol);
     63 
     64    function f() {
     65        var actual = 0;
     66        var expected = 0;
     67        for (var i = 0; i < 1000; i++) {
     68            var obj = objects[i % objects.length];
     69            actual += obj[symbol];
     70            expected += obj._prop;
     71        }
     72        assertEq(actual, expected);
     73    }
     74 
     75    for (var i = 0; i < 2; ++i) {
     76        f();
     77    }
     78 }
     79 testSymbol();