allocations.js

dbg = null;
Components.utils.forceGC();

Components.utils.import("resource://gre/modules/devtools/Loader.jsm");
Debugger = devtools.require("Debugger");

dbg = devtools.require("devtools/server/actors/utils/make-debugger")({
  findDebuggees: dbg => dbg.findAllGlobals(),
  shouldAddNewGlobalAsDebuggee: () => true
});
dbg.addDebuggees();

console.log(dbg);

dbg.memory.allocationSamplingProbability = 1;
dbg.memory.trackingAllocationSites = true;

devtools.require("sdk/timers").setTimeout(() => {
  console.log("=====================================================================================");

  console.time("census");
  let census = dbg.memory.takeCensus({
    breakdown: {
      by: "allocationStack",
      then: { by: "count", count: true, bytes: true },
      noStack: { by: "count", count: true, bytes: true }
    },
  });
  dbg.memory.trackingAllocationSites = false;
  console.timeEnd("census");
  console.log(census);

  console.log("=====================================================================================");

  let i = 0;
  var results = [];
  var totalBytes = 0;
  var bytesExplained = 0;
  census.forEach((v, k) => {
    if (k.toString().indexOf('l20n.js') === -1) {
      return;
    }
    totalBytes += v.bytes;
    results.push({stack: k.toString(), value: v});
  });

  results.sort(function(a, b) {
    return b.value.bytes - a.value.bytes;
  });

  results.slice(0, 30).forEach(res => {
    console.log(res.stack)
    console.log(res.value);
    console.log();
    bytesExplained += res.value.bytes;
  });
  console.log('Total bytes: ' + totalBytes);
  console.log('Top 30 allocations explains: ' + bytesExplained + ' bytes');
}, 2000);