gecko-dev/tools/profiler/tests/head_profiler.js

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

var {Services} = ChromeUtils.import("resource://gre/modules/Services.jsm");
var {AppConstants} = ChromeUtils.import("resource://gre/modules/AppConstants.jsm");

function getInflatedStackLocations(thread, sample) {
  let stackTable = thread.stackTable;
  let frameTable = thread.frameTable;
  let stringTable = thread.stringTable;
  let SAMPLE_STACK_SLOT = thread.samples.schema.stack;
  let STACK_PREFIX_SLOT = stackTable.schema.prefix;
  let STACK_FRAME_SLOT = stackTable.schema.frame;
  let FRAME_LOCATION_SLOT = frameTable.schema.location;

  // Build the stack from the raw data and accumulate the locations in
  // an array.
  let stackIndex = sample[SAMPLE_STACK_SLOT];
  let locations = [];
  while (stackIndex !== null) {
    let stackEntry = stackTable.data[stackIndex];
    let frame = frameTable.data[stackEntry[STACK_FRAME_SLOT]];
    locations.push(stringTable[frame[FRAME_LOCATION_SLOT]]);
    stackIndex = stackEntry[STACK_PREFIX_SLOT];
  }

  // The profiler tree is inverted, so reverse the array.
  return locations.reverse();
}