importer/v8/codemap.js

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

'use strict';

base.require('tracing.importer.v8.splaytree');

/**
 * @fileoverview Map addresses to dynamically created functions.
 */

base.exportTo('tracing.importer.v8', function() {
  /**
   * Constructs a mapper that maps addresses into code entries.
   *
   * @constructor
   */
  function CodeMap() {
    /**
     * Dynamic code entries. Used for JIT compiled code.
     */
    this.dynamics_ = new tracing.importer.v8.SplayTree();

    /**
     * Name generator for entries having duplicate names.
     */
    this.dynamicsNameGen_ = new tracing.importer.v8.CodeMap.NameGenerator();

    /**
     * Static code entries. Used for statically compiled code.
     */
    this.statics_ = new tracing.importer.v8.SplayTree();

    /**
     * Libraries entries. Used for the whole static code libraries.
     */
    this.libraries_ = new tracing.importer.v8.SplayTree();

    /**
     * Map of memory pages occupied with static code.
     */
    this.pages_ = [];
  };


  /**
   * The number of alignment bits in a page address.
   */
  CodeMap.PAGE_ALIGNMENT = 12;


  /**
   * Page size in bytes.
   */
  CodeMap.PAGE_SIZE =
      1 << CodeMap.PAGE_ALIGNMENT;


  /**
   * Adds a dynamic (i.e. moveable and discardable) code entry.
   *
   * @param {number} start The starting address.
   * @param {CodeMap.CodeEntry} codeEntry Code entry object.
   */
  CodeMap.prototype.addCode = function(start, codeEntry) {
    this.deleteAllCoveredNodes_(this.dynamics_, start, start + codeEntry.size);
    this.dynamics_.insert(start, codeEntry);
  };


  /**
   * Moves a dynamic code entry. Throws an exception if there is no dynamic
   * code entry with the specified starting address.
   *
   * @param {number} from The starting address of the entry being moved.
   * @param {number} to The destination address.
   */
  CodeMap.prototype.moveCode = function(from, to) {
    var removedNode = this.dynamics_.remove(from);
    this.deleteAllCoveredNodes_(this.dynamics_, to,
                                to + removedNode.value.size);
    this.dynamics_.insert(to, removedNode.value);
  };


  /**
   * Discards a dynamic code entry. Throws an exception if there is no dynamic
   * code entry with the specified starting address.
   *
   * @param {number} start The starting address of the entry being deleted.
   */
  CodeMap.prototype.deleteCode = function(start) {
    var removedNode = this.dynamics_.remove(start);
  };


  /**
   * Adds a library entry.
   *
   * @param {number} start The starting address.
   * @param {CodeMap.CodeEntry} codeEntry Code entry object.
   */
  CodeMap.prototype.addLibrary = function(
      start, codeEntry) {
    this.markPages_(start, start + codeEntry.size);
    this.libraries_.insert(start, codeEntry);
  };


  /**
   * Adds a static code entry.
   *
   * @param {number} start The starting address.
   * @param {CodeMap.CodeEntry} codeEntry Code entry object.
   */
  CodeMap.prototype.addStaticCode = function(
      start, codeEntry) {
    this.statics_.insert(start, codeEntry);
  };


  /**
   * @private
   */
  CodeMap.prototype.markPages_ = function(start, end) {
    for (var addr = start; addr <= end;
         addr += CodeMap.PAGE_SIZE) {
      this.pages_[addr >>> CodeMap.PAGE_ALIGNMENT] = 1;
    }
  };


  /**
   * @private
   */
  CodeMap.prototype.deleteAllCoveredNodes_ = function(tree, start, end) {
    var to_delete = [];
    var addr = end - 1;
    while (addr >= start) {
      var node = tree.findGreatestLessThan(addr);
      if (!node) break;
      var start2 = node.key, end2 = start2 + node.value.size;
      if (start2 < end && start < end2) to_delete.push(start2);
      addr = start2 - 1;
    }
    for (var i = 0, l = to_delete.length; i < l; ++i) tree.remove(to_delete[i]);
  };


  /**
   * @private
   */
  CodeMap.prototype.isAddressBelongsTo_ = function(addr, node) {
    return addr >= node.key && addr < (node.key + node.value.size);
  };


  /**
   * @private
   */
  CodeMap.prototype.findInTree_ = function(tree, addr) {
    var node = tree.findGreatestLessThan(addr);
    return node && this.isAddressBelongsTo_(addr, node) ? node.value : null;
  };


  /**
   * Finds a code entry that contains the specified address. Both static and
   * dynamic code entries are considered.
   *
   * @param {number} addr Address.
   */
  CodeMap.prototype.findEntry = function(addr) {
    var pageAddr = addr >>> CodeMap.PAGE_ALIGNMENT;
    if (pageAddr in this.pages_) {
      // Static code entries can contain "holes" of unnamed code.
      // In this case, the whole library is assigned to this address.
      return this.findInTree_(this.statics_, addr) ||
          this.findInTree_(this.libraries_, addr);
    }
    var min = this.dynamics_.findMin();
    var max = this.dynamics_.findMax();
    if (max != null && addr < (max.key + max.value.size) && addr >= min.key) {
      var dynaEntry = this.findInTree_(this.dynamics_, addr);
      if (dynaEntry == null) return null;
      // Dedupe entry name.
      if (!dynaEntry.nameUpdated_) {
        dynaEntry.name = this.dynamicsNameGen_.getName(dynaEntry.name);
        dynaEntry.nameUpdated_ = true;
      }
      return dynaEntry;
    }
    return null;
  };


  /**
   * Returns a dynamic code entry using its starting address.
   *
   * @param {number} addr Address.
   */
  CodeMap.prototype.findDynamicEntryByStartAddress =
      function(addr) {
    var node = this.dynamics_.find(addr);
    return node ? node.value : null;
  };


  /**
   * Returns an array of all dynamic code entries.
   */
  CodeMap.prototype.getAllDynamicEntries = function() {
    return this.dynamics_.exportValues();
  };


  /**
   * Returns an array of pairs of all dynamic code entries and their addresses.
   */
  CodeMap.prototype.getAllDynamicEntriesWithAddresses = function() {
    return this.dynamics_.exportKeysAndValues();
  };


  /**
   * Returns an array of all static code entries.
   */
  CodeMap.prototype.getAllStaticEntries = function() {
    return this.statics_.exportValues();
  };


  /**
   * Returns an array of all libraries entries.
   */
  CodeMap.prototype.getAllLibrariesEntries = function() {
    return this.libraries_.exportValues();
  };


  /**
   * Creates a code entry object.
   *
   * @param {number} size Code entry size in bytes.
   * @param {string=} opt_name Code entry name.
   * @constructor
   */
  CodeMap.CodeEntry = function(size, opt_name) {
    this.size = size;
    this.name = opt_name || '';
    this.nameUpdated_ = false;
  };


  CodeMap.CodeEntry.prototype.getName = function() {
    return this.name;
  };


  CodeMap.CodeEntry.prototype.toString = function() {
    return this.name + ': ' + this.size.toString(16);
  };


  CodeMap.NameGenerator = function() {
    this.knownNames_ = {};
  };


  CodeMap.NameGenerator.prototype.getName = function(name) {
    if (!(name in this.knownNames_)) {
      this.knownNames_[name] = 0;
      return name;
    }
    var count = ++this.knownNames_[name];
    return name + ' {' + count + '}';
  };
  return {
    CodeMap: CodeMap
  };
});