Implemented Profile object that processes profiling events and calculates profiling data.

Review URL: http://codereview.chromium.org/77014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1739 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/mjsunit/tools/profile.js

+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Load source code files from <project root>/tools.
+// Files: tools/splaytree.js tools/codemap.js tools/profile.js
+
+
+function stackToString(stack) {
+  return stack.join(' -> ');
+};
+
+
+function assertPathExists(root, path, opt_message) {
+  var message = opt_message ? ' (' + opt_message + ')' : '';
+  assertNotNull(root.descendToChild(path, function(node, pos) {
+    assertNotNull(node,
+      stackToString(path.slice(0, pos)) + ' has no child ' +
+                    path[pos] + message);
+  }), opt_message);
+};
+
+
+function assertNoPathExists(root, path, opt_message) {
+  var message = opt_message ? ' (' + opt_message + ')' : '';
+  assertNull(root.descendToChild(path), opt_message);
+};
+
+
+function countNodes(profile, traverseFunc) {
+  var count = 0;
+  traverseFunc.call(profile, function () { count++; });
+  return count;
+};
+
+
+function ProfileTestDriver() {
+  this.profile = new devtools.profiler.Profile();
+  this.stack_ = [];
+  this.addFunctions_();
+};
+
+
+// Addresses inside functions.
+ProfileTestDriver.prototype.funcAddrs_ = {
+    'lib1-f1': 0x11110, 'lib1-f2': 0x11210,
+    'lib2-f1': 0x21110, 'lib2-f2': 0x21210,
+    'T: F1': 0x50110, 'T: F2': 0x50210, 'T: F3': 0x50410 };
+
+
+ProfileTestDriver.prototype.addFunctions_ = function() {
+  this.profile.addStaticCode('lib1', 0x11000, 0x12000);
+  this.profile.addStaticCode('lib1-f1', 0x11100, 0x11900);
+  this.profile.addStaticCode('lib1-f2', 0x11200, 0x11500);
+  this.profile.addStaticCode('lib2', 0x21000, 0x22000);
+  this.profile.addStaticCode('lib2-f1', 0x21100, 0x21900);
+  this.profile.addStaticCode('lib2-f2', 0x21200, 0x21500);
+  this.profile.addCode('T', 'F1', 0x50100, 0x100);
+  this.profile.addCode('T', 'F2', 0x50200, 0x100);
+  this.profile.addCode('T', 'F3', 0x50400, 0x100);
+};
+
+
+ProfileTestDriver.prototype.enter = function(funcName) {
+  // Stack looks like this: [pc, caller, ..., main].
+  // Therefore, we are adding entries at the beginning.
+  this.stack_.unshift(this.funcAddrs_[funcName]);
+  this.profile.recordTick(this.stack_);
+};
+
+
+ProfileTestDriver.prototype.stay = function() {
+  this.profile.recordTick(this.stack_);
+};
+
+
+ProfileTestDriver.prototype.leave = function() {
+  this.stack_.shift();
+};
+
+
+ProfileTestDriver.prototype.execute = function() {
+  this.enter('lib1-f1');
+    this.enter('lib1-f2');
+      this.enter('T: F1');
+        this.enter('T: F2');
+        this.leave();
+      this.stay();
+        this.enter('lib2-f1');
+          this.enter('lib2-f1');
+          this.leave();
+        this.stay();
+        this.leave();
+        this.enter('T: F3');
+          this.enter('T: F3');
+            this.enter('T: F3');
+            this.leave();
+            this.enter('T: F2');
+            this.stay();
+            this.leave();
+          this.leave();
+        this.leave();
+      this.leave();
+    this.stay();
+  this.leave();
+};
+
+
+function Inherits(childCtor, parentCtor) {
+  function tempCtor() {};
+  tempCtor.prototype = parentCtor.prototype;
+  childCtor.superClass_ = parentCtor.prototype;
+  childCtor.prototype = new tempCtor();
+  childCtor.prototype.constructor = childCtor;
+};
+
+
+(function testCallTreeBuilding() {
+  function Driver() {
+    ProfileTestDriver.call(this);
+    this.namesTopDown = [];
+    this.namesBottomUp = [];
+  };
+  Inherits(Driver, ProfileTestDriver);
+
+  Driver.prototype.enter = function(func) {
+    this.namesTopDown.push(func);
+    this.namesBottomUp.unshift(func);
+    assertNoPathExists(this.profile.getTopDownTreeRoot(), this.namesTopDown,
+        'pre enter/topDown');
+    assertNoPathExists(this.profile.getBottomUpTreeRoot(), this.namesBottomUp,
+        'pre enter/bottomUp');
+    Driver.superClass_.enter.call(this, func);
+    assertPathExists(this.profile.getTopDownTreeRoot(), this.namesTopDown,
+        'post enter/topDown');
+    assertPathExists(this.profile.getBottomUpTreeRoot(), this.namesBottomUp,
+        'post enter/bottomUp');
+  };
+
+  Driver.prototype.stay = function() {
+    var preTopDownNodes = countNodes(this.profile, this.profile.traverseTopDownTree);
+    var preBottomUpNodes = countNodes(this.profile, this.profile.traverseBottomUpTree);
+    Driver.superClass_.stay.call(this);
+    var postTopDownNodes = countNodes(this.profile, this.profile.traverseTopDownTree);
+    var postBottomUpNodes = countNodes(this.profile, this.profile.traverseBottomUpTree);
+    // Must be no changes in tree layout.
+    assertEquals(preTopDownNodes, postTopDownNodes, 'stay/topDown');
+    assertEquals(preBottomUpNodes, postBottomUpNodes, 'stay/bottomUp');
+  };
+
+  Driver.prototype.leave = function() {
+    Driver.superClass_.leave.call(this);
+    this.namesTopDown.pop();
+    this.namesBottomUp.shift();
+  };
+
+  var testDriver = new Driver();
+  testDriver.execute();
+})();
+
+
+function assertNodeWeights(root, path, selfTicks, totalTicks) {
+  var node = root.descendToChild(path);
+  var stack = stackToString(path);
+  assertNotNull(node, 'node not found: ' + stack);
+  assertEquals(selfTicks, node.selfWeight, 'self of ' + stack);
+  assertEquals(totalTicks, node.totalWeight, 'total of ' + stack);
+};
+
+
+(function testTopDownRootProfileTicks() {
+  var testDriver = new ProfileTestDriver();
+  testDriver.execute();
+
+  var pathWeights = [
+    [['lib1-f1'], 1, 14],
+    [['lib1-f1', 'lib1-f2'], 2, 13],
+    [['lib1-f1', 'lib1-f2', 'T: F1'], 2, 11],
+    [['lib1-f1', 'lib1-f2', 'T: F1', 'T: F2'], 1, 1],
+    [['lib1-f1', 'lib1-f2', 'T: F1', 'lib2-f1'], 2, 3],
+    [['lib1-f1', 'lib1-f2', 'T: F1', 'lib2-f1', 'lib2-f1'], 1, 1],
+    [['lib1-f1', 'lib1-f2', 'T: F1', 'T: F3'], 1, 5],
+    [['lib1-f1', 'lib1-f2', 'T: F1', 'T: F3', 'T: F3'], 1, 4],
+    [['lib1-f1', 'lib1-f2', 'T: F1', 'T: F3', 'T: F3', 'T: F3'], 1, 1],
+    [['lib1-f1', 'lib1-f2', 'T: F1', 'T: F3', 'T: F3', 'T: F2'], 2, 2]
+  ];
+
+  var root = testDriver.profile.getTopDownTreeRoot();
+  for (var i = 0; i < pathWeights.length; ++i) {
+    var data = pathWeights[i];
+    assertNodeWeights(root, data[0], data[1], data[2]);
+  }
+})();
+
+
+(function testRootFlatProfileTicks() {
+  function Driver() {
+    ProfileTestDriver.call(this);
+    this.namesTopDown = [''];
+    this.counters = {};
+  };
+  Inherits(Driver, ProfileTestDriver);
+
+  Driver.prototype.increment = function(func, self, total) {
+    if (!(func in this.counters)) {
+      this.counters[func] = { self: 0, total: 0 };
+    }
+    this.counters[func].self += self;
+    this.counters[func].total += total;
+  };
+
+  Driver.prototype.incrementTotals = function() {
+    // Only count each function in the stack once.
+    var met = {};
+    for (var i = 0; i < this.namesTopDown.length; ++i) {
+      var name = this.namesTopDown[i];
+      if (!(name in met)) {
+        this.increment(name, 0, 1);
+      }
+      met[name] = true;
+    }
+  };
+
+  Driver.prototype.enter = function(func) {
+    Driver.superClass_.enter.call(this, func);
+    this.namesTopDown.push(func);
+    this.increment(func, 1, 0);
+    this.incrementTotals();
+  };
+
+  Driver.prototype.stay = function() {
+    Driver.superClass_.stay.call(this);
+    this.increment(this.namesTopDown[this.namesTopDown.length - 1], 1, 0);
+    this.incrementTotals();
+  };
+
+  Driver.prototype.leave = function() {
+    Driver.superClass_.leave.call(this);
+    this.namesTopDown.pop();
+  };
+
+  var testDriver = new Driver();
+  testDriver.execute();
+
+  var counted = 0;
+  for (var c in testDriver.counters) {
+    counted++;
+  }
+
+  var flatProfile = testDriver.profile.getFlatProfile();
+  assertEquals(counted, flatProfile.length, 'counted vs. flatProfile');
+  for (var i = 0; i < flatProfile.length; ++i) {
+    var rec = flatProfile[i];
+    assertTrue(rec.label in testDriver.counters, 'uncounted: ' + rec.label);
+    var reference = testDriver.counters[rec.label];
+    assertEquals(reference.self, rec.selfWeight, 'self of ' + rec.label);
+    assertEquals(reference.total, rec.totalWeight, 'total of ' + rec.label);
+  }
+
+})();

tools/codemap.js

@@ -200,6 +200,11 @@ devtools.profiler.CodeMap.CodeEntry = function(size, opt_name) {
 };
 
 
+devtools.profiler.CodeMap.CodeEntry.prototype.getName = function() {
+  return this.name;
+};
+
+    
 devtools.profiler.CodeMap.CodeEntry.prototype.toString = function() {
   return this.name + ': ' + this.size.toString(16);
 };

tools/profile.js

+// Copyright 2009 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Initlialize namespaces
+var devtools = devtools || {};
+devtools.profiler = devtools.profiler || {};
+
+
+/**
+ * Creates a profile object for processing profiling-related events
+ * and calculating function execution times.
+ *
+ * @constructor
+ */
+devtools.profiler.Profile = function() {
+  this.codeMap_ = new devtools.profiler.CodeMap();
+  this.topDownTree_ = new devtools.profiler.CallTree();
+  this.bottomUpTree_ = new devtools.profiler.CallTree();
+};
+
+
+/**
+ * Returns whether a function with the specified name must be skipped.
+ * Should be overriden by subclasses.
+ *
+ * @param {string} name Function name.
+ */
+devtools.profiler.Profile.prototype.skipThisFunction = function(name) {
+  return false;
+};
+
+
+/**
+ * Called whenever the specified operation has failed finding a function
+ * containing the specified address. Should be overriden by subclasses.
+ * Operation is one of the following: 'move', 'delete', 'tick'.
+ *
+ * @param {string} operation Operation name.
+ * @param {number} addr Address of the unknown code.
+ */
+devtools.profiler.Profile.prototype.handleUnknownCode = function(
+    operation, addr) {
+};
+
+
+/**
+ * Registers static (library) code entry.
+ *
+ * @param {string} name Code entry name.
+ * @param {number} startAddr Starting address.
+ * @param {number} endAddr Ending address.
+ */
+devtools.profiler.Profile.prototype.addStaticCode = function(
+    name, startAddr, endAddr) {
+  this.codeMap_.addStaticCode(startAddr,
+      new devtools.profiler.CodeMap.CodeEntry(endAddr - startAddr, name));
+};
+
+
+/**
+ * Registers dynamic (JIT-compiled) code entry.
+ *
+ * @param {string} type Code entry type.
+ * @param {string} name Code entry name.
+ * @param {number} start Starting address.
+ * @param {number} size Code entry size.
+ */
+devtools.profiler.Profile.prototype.addCode = function(
+    type, name, start, size) {
+  this.codeMap_.addCode(start,
+      new devtools.profiler.Profile.DynamicCodeEntry(size, type, name));
+};
+
+
+/**
+ * Reports about moving of a dynamic code entry.
+ *
+ * @param {number} from Current code entry address.
+ * @param {number} to New code entry address.
+ */
+devtools.profiler.Profile.prototype.moveCode = function(from, to) {
+  try {
+    this.codeMap_.moveCode(from, to);
+  } catch (e) {
+    this.handleUnknownCode('move', from);
+  }
+};
+
+
+/**
+ * Reports about deletion of a dynamic code entry.
+ *
+ * @param {number} start Starting address.
+ */
+devtools.profiler.Profile.prototype.deleteCode = function(start) {
+  try {
+    this.codeMap_.deleteCode(start);
+  } catch (e) {
+    this.handleUnknownCode('delete', start);
+  }
+};
+
+
+/**
+ * Records a tick event. Stack must contain a sequence of
+ * addresses starting with the program counter value.
+ *
+ * @param {Array<number>} stack Stack sample.
+ */
+devtools.profiler.Profile.prototype.recordTick = function(stack) {
+  var processedStack = this.resolveAndFilterFuncs_(stack);
+  this.bottomUpTree_.addPath(processedStack);
+  processedStack.reverse();
+  this.topDownTree_.addPath(processedStack);
+};
+
+
+/**
+ * Translates addresses into function names and filters unneeded
+ * functions.
+ *
+ * @param {Array<number>} stack Stack sample.
+ */
+devtools.profiler.Profile.prototype.resolveAndFilterFuncs_ = function(stack) {
+  var result = [];
+  for (var i = 0; i < stack.length; ++i) {
+    var entry = this.codeMap_.findEntry(stack[i]);
+    if (entry) {
+      var name = entry.getName();
+      if (!this.skipThisFunction(name)) {
+        result.push(name);
+      }
+    } else {
+      this.handleUnknownCode('tick', stack[i]);
+    }
+  }
+  return result;
+};
+
+
+/**
+ * Returns the root of the top down call graph.
+ */
+devtools.profiler.Profile.prototype.getTopDownTreeRoot = function() {
+  this.topDownTree_.computeTotalWeights();
+  return this.topDownTree_.root_;
+};
+
+
+/**
+ * Returns the root of the bottom up call graph.
+ */
+devtools.profiler.Profile.prototype.getBottomUpTreeRoot = function() {
+  this.bottomUpTree_.computeTotalWeights();
+  return this.bottomUpTree_.root_;
+};
+
+
+/**
+ * Traverses the top down call graph in preorder.
+ *
+ * @param {function(devtools.profiler.CallTree.Node)} f Visitor function.
+ */
+devtools.profiler.Profile.prototype.traverseTopDownTree = function(f) {
+  this.topDownTree_.traverse(f);
+};
+
+
+/**
+ * Traverses the bottom up call graph in preorder.
+ *
+ * @param {function(devtools.profiler.CallTree.Node)} f Visitor function.
+ */
+devtools.profiler.Profile.prototype.traverseBottomUpTree = function(f) {
+  this.bottomUpTree_.traverse(f);
+};
+
+
+/**
+ * Calculates a flat profile of callees starting from the specified node.
+ *
+ * @param {devtools.profiler.CallTree.Node} opt_root Starting node.
+ */
+devtools.profiler.Profile.prototype.getFlatProfile = function(opt_root) {
+  var counters = new devtools.profiler.CallTree.Node('');
+  var precs = {};
+  this.topDownTree_.computeTotalWeights();
+  this.topDownTree_.traverseInDepth(
+    function onEnter(node) {
+      if (!(node.label in precs)) {
+        precs[node.label] = 0;
+      }
+      var rec = counters.findOrAddChild(node.label);
+      rec.selfWeight += node.selfWeight;
+      if (precs[node.label] == 0) {
+        rec.totalWeight += node.totalWeight;
+      }
+      precs[node.label]++;
+    },
+    function onExit(node) {
+      precs[node.label]--;
+    },
+    opt_root);
+  return counters.exportChildren();
+};
+
+
+/**
+ * Creates a dynamic code entry.
+ *
+ * @param {number} size Code size.
+ * @param {string} type Code type.
+ * @param {string} name Function name.
+ * @constructor
+ */
+devtools.profiler.Profile.DynamicCodeEntry = function(size, type, name) {
+  devtools.profiler.CodeMap.CodeEntry.call(this, size, name);
+  this.type = type;
+};
+
+
+/**
+ * Returns node name.
+ */
+devtools.profiler.Profile.DynamicCodeEntry.prototype.getName = function() {
+  var name = this.name;
+  if (name.length == 0) {
+    name = '<anonymous>';
+  } else if (name.charAt(0) == ' ') {
+    // An anonymous function with location: " aaa.js:10".
+    name = '<anonymous>' + name;
+  }
+  return this.type + ': ' + name;
+};
+
+
+/**
+ * Constructs a call graph.
+ *
+ * @constructor
+ */
+devtools.profiler.CallTree = function() {
+  this.root_ = new devtools.profiler.CallTree.Node('');
+};
+
+
+/**
+ * @private
+ */
+devtools.profiler.CallTree.prototype.totalsComputed_ = false;
+
+
+/**
+ * Adds the specified call path, constructing nodes as necessary.
+ *
+ * @param {Array<string>} path Call path.
+ */
+devtools.profiler.CallTree.prototype.addPath = function(path) {
+  if (path.length == 0) {
+    return;
+  }
+  var curr = this.root_;
+  for (var i = 0; i < path.length; ++i) {
+    curr = curr.findOrAddChild(path[i]);
+  }
+  curr.selfWeight++;
+  this.totalsComputed_ = false;
+};
+
+
+/**
+ * Computes total weights in the call graph.
+ */
+devtools.profiler.CallTree.prototype.computeTotalWeights = function() {
+  if (this.totalsComputed_) {
+    return;
+  }
+  this.root_.computeTotalWeight();
+  this.totalsComputed_ = true;
+};
+
+
+/**
+ * Traverses the call graph in preorder.
+ *
+ * @param {function(devtools.profiler.CallTree.Node)} f Visitor function.
+ * @param {devtools.profiler.CallTree.Node} opt_start Starting node.
+ */
+devtools.profiler.CallTree.prototype.traverse = function(f, opt_start) {
+  var nodesToVisit = [opt_start || this.root_];
+  while (nodesToVisit.length > 0) {
+    var node = nodesToVisit.shift();
+    f(node);
+    nodesToVisit = nodesToVisit.concat(node.exportChildren());
+  }
+};
+
+
+/**
+ * Performs an indepth call graph traversal.
+ *
+ * @param {function(devtools.profiler.CallTree.Node)} enter A function called
+ *     prior to visiting node's children.
+ * @param {function(devtools.profiler.CallTree.Node)} exit A function called
+ *     after visiting node's children.
+ * @param {devtools.profiler.CallTree.Node} opt_start Starting node.
+ */
+devtools.profiler.CallTree.prototype.traverseInDepth = function(
+    enter, exit, opt_start) {
+  function traverse(node) {
+    enter(node);
+    node.forEachChild(traverse);
+    exit(node);
+  }
+  traverse(opt_start || this.root_);
+};
+
+
+/**
+ * Constructs a call graph node.
+ *
+ * @param {string} label Node label.
+ * @param {devtools.profiler.CallTree.Node} opt_parent Node parent.
+ */
+devtools.profiler.CallTree.Node = function(label, opt_parent) {
+  this.label = label;
+  this.parent = opt_parent;
+  this.children = {};
+};
+
+
+/**
+ * Node self weight (how many times this node was the last node in
+ * a call path).
+ * @type {number}
+ */
+devtools.profiler.CallTree.Node.prototype.selfWeight = 0;
+
+
+/**
+ * Node total weight (includes weights of all children).
+ * @type {number}
+ */
+devtools.profiler.CallTree.Node.prototype.totalWeight = 0;
+
+
+/**
+ * Adds a child node.
+ *
+ * @param {string} label Child node label.
+ */
+devtools.profiler.CallTree.Node.prototype.addChild = function(label) {
+  var child = new devtools.profiler.CallTree.Node(label, this);
+  this.children[label] = child;
+  return child;
+};
+
+
+/**
+ * Computes node's total weight.
+ */
+devtools.profiler.CallTree.Node.prototype.computeTotalWeight =
+    function() {
+  var totalWeight = this.selfWeight;
+  this.forEachChild(function(child) {
+      totalWeight += child.computeTotalWeight(); });
+  return this.totalWeight = totalWeight;
+};
+
+
+/**
+ * Returns all node's children as an array.
+ */
+devtools.profiler.CallTree.Node.prototype.exportChildren = function() {
+  var result = [];
+  this.forEachChild(function (node) { result.push(node); });
+  return result;
+};
+
+
+/**
+ * Finds an immediate child with the specified label.
+ *
+ * @param {string} label Child node label.
+ */
+devtools.profiler.CallTree.Node.prototype.findChild = function(label) {
+  return this.children[label] || null;
+};
+
+
+/**
+ * Finds an immediate child with the specified label, creates a child
+ * node if necessary.
+ *
+ * @param {string} label Child node label.
+ */
+devtools.profiler.CallTree.Node.prototype.findOrAddChild = function(
+    label) {
+  return this.findChild(label) || this.addChild(label);
+};
+
+
+/**
+ * Calls the specified function for every child.
+ *
+ * @param {function(devtools.profiler.CallTree.Node)} f Visitor function.
+ */
+devtools.profiler.CallTree.Node.prototype.forEachChild = function(f) {
+  for (var c in this.children) {
+    f(this.children[c]);
+  }
+};
+
+
+/**
+ * Walks up from the current node up to the call tree root.
+ *
+ * @param {function(devtools.profiler.CallTree.Node)} f Visitor function.
+ */
+devtools.profiler.CallTree.Node.prototype.walkUpToRoot = function(f) {
+  for (var curr = this; curr != null; curr = curr.parent) {
+    f(curr);
+  }
+};
+
+
+/**
+ * Tries to find a node with the specified path.
+ *
+ * @param {Array<string>} labels The path.
+ * @param {function(devtools.profiler.CallTree.Node)} opt_f Visitor function.
+ */
+devtools.profiler.CallTree.Node.prototype.descendToChild = function(
+    labels, opt_f) {
+  for (var pos = 0, curr = this; pos < labels.length && curr != null; pos++) {
+    var child = curr.findChild(labels[pos]);
+    if (opt_f) {
+      opt_f(child, pos);
+    }
+    curr = child;
+  }
+  return curr;
+};