test_HeapSnapshot_takeCensus_02.js

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/* Any copyright is dedicated to the Public Domain.

   http://creativecommons.org/publicdomain/zero/1.0/ */

"use strict";

// HeapSnapshot.prototype.takeCensus behaves plausibly as we allocate objects.

//

// Exact object counts vary in ways we can't predict. For example,

// BaselineScripts can hold onto "template objects", which exist only to hold

// the shape and type for newly created objects. When BaselineScripts are

// discarded, these template objects go with them.

//

// So instead of expecting precise counts, we expect counts that are at least as

// many as we would expect given the object graph we've built.

//

// Ported from js/src/jit-tests/debug/Memory-takeCensus-02.js

function run_test() {

  // A Debugger with no debuggees had better not find anything.

  const dbg = new Debugger();

  const census0 = saveHeapSnapshotAndTakeCensus(dbg);

  Census.walkCensus(census0, "census0", Census.assertAllZeros);

  function newGlobalWithDefs() {

    const g = newGlobal();

    g.eval(`

           function times(n, fn) {

             var a=[];

             for (var i = 0; i<n; i++)

               a.push(fn());

             return a;

`);

    return g;

  // Allocate a large number of various types of objects, and check that census

  // finds them.

  const g = newGlobalWithDefs();

  dbg.addDebuggee(g);

  g.eval("var objs = times(100, () => ({}));");

  g.eval("var rxs  = times(200, () => /foo/);");

  g.eval("var ars  = times(400, () => []);");

  g.eval("var fns  = times(800, () => () => {});");

  const census1 = dbg.memory.takeCensus(dbg);

  Census.walkCensus(

    census1,

    "census1",

    Census.assertAllNotLessThan({

      objects: {

        Object: { count: 100 },

        RegExp: { count: 200 },

        Array: { count: 400 },

        Function: { count: 800 },

},

})

);

  do_test_finished();