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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /devtools/shared/heapsnapshot/CensusUtils.js | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'devtools/shared/heapsnapshot/CensusUtils.js')
-rw-r--r-- | devtools/shared/heapsnapshot/CensusUtils.js | 489 |
1 files changed, 489 insertions, 0 deletions
diff --git a/devtools/shared/heapsnapshot/CensusUtils.js b/devtools/shared/heapsnapshot/CensusUtils.js new file mode 100644 index 000000000..36bdd2d82 --- /dev/null +++ b/devtools/shared/heapsnapshot/CensusUtils.js @@ -0,0 +1,489 @@ +/* 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/. */ +"use strict"; + +const { flatten } = require("resource://devtools/shared/ThreadSafeDevToolsUtils.js"); + +/** * Visitor ****************************************************************/ + +/** + * A Visitor visits each node and edge of a census report tree as the census + * report is being traversed by `walk`. + */ +function Visitor() { } +exports.Visitor = Visitor; + +/** + * The `enter` method is called when a new sub-report is entered in traversal. + * + * @param {Object} breakdown + * The breakdown for the sub-report that is being entered by traversal. + * + * @param {Object} report + * The report generated by the given breakdown. + * + * @param {any} edge + * The edge leading to this sub-report. The edge is null if (but not iff! + * eg, null allocation stack edges) we are entering the root report. + */ +Visitor.prototype.enter = function (breakdown, report, edge) { }; + +/** + * The `exit` method is called when traversal of a sub-report has finished. + * + * @param {Object} breakdown + * The breakdown for the sub-report whose traversal has finished. + * + * @param {Object} report + * The report generated by the given breakdown. + * + * @param {any} edge + * The edge leading to this sub-report. The edge is null if (but not iff! + * eg, null allocation stack edges) we are entering the root report. + */ +Visitor.prototype.exit = function (breakdown, report, edge) { }; + +/** + * The `count` method is called when leaf nodes (reports whose breakdown is + * by: "count") in the report tree are encountered. + * + * @param {Object} breakdown + * The count breakdown for this report. + * + * @param {Object} report + * The report generated by a breakdown by "count". + * + * @param {any|null} edge + * The edge leading to this count report. The edge is null if we are + * entering the root report. + */ +Visitor.prototype.count = function (breakdown, report, edge) { }; + +/** * getReportEdges *********************************************************/ + +const EDGES = Object.create(null); + +EDGES.count = function (breakdown, report) { + return []; +}; + +EDGES.bucket = function (breakdown, report) { + return []; +}; + +EDGES.internalType = function (breakdown, report) { + return Object.keys(report).map(key => ({ + edge: key, + referent: report[key], + breakdown: breakdown.then + })); +}; + +EDGES.objectClass = function (breakdown, report) { + return Object.keys(report).map(key => ({ + edge: key, + referent: report[key], + breakdown: key === "other" ? breakdown.other : breakdown.then + })); +}; + +EDGES.coarseType = function (breakdown, report) { + return [ + { edge: "objects", referent: report.objects, breakdown: breakdown.objects }, + { edge: "scripts", referent: report.scripts, breakdown: breakdown.scripts }, + { edge: "strings", referent: report.strings, breakdown: breakdown.strings }, + { edge: "other", referent: report.other, breakdown: breakdown.other }, + ]; +}; + +EDGES.allocationStack = function (breakdown, report) { + const edges = []; + report.forEach((value, key) => { + edges.push({ + edge: key, + referent: value, + breakdown: key === "noStack" ? breakdown.noStack : breakdown.then + }); + }); + return edges; +}; + +EDGES.filename = function (breakdown, report) { + return Object.keys(report).map(key => ({ + edge: key, + referent: report[key], + breakdown: key === "noFilename" ? breakdown.noFilename : breakdown.then + })); +}; + +/** + * Get the set of outgoing edges from `report` as specified by the given + * breakdown. + * + * @param {Object} breakdown + * The census breakdown. + * + * @param {Object} report + * The census report. + */ +function getReportEdges(breakdown, report) { + return EDGES[breakdown.by](breakdown, report); +} +exports.getReportEdges = getReportEdges; + +/** * walk *******************************************************************/ + +function recursiveWalk(breakdown, edge, report, visitor) { + if (breakdown.by === "count") { + visitor.enter(breakdown, report, edge); + visitor.count(breakdown, report, edge); + visitor.exit(breakdown, report, edge); + } else { + visitor.enter(breakdown, report, edge); + for (let { edge, referent, breakdown: subBreakdown } of getReportEdges(breakdown, report)) { + recursiveWalk(subBreakdown, edge, referent, visitor); + } + visitor.exit(breakdown, report, edge); + } +} + +/** + * Walk the given `report` that was generated by taking a census with the + * specified `breakdown`. + * + * @param {Object} breakdown + * The census breakdown. + * + * @param {Object} report + * The census report. + * + * @param {Visitor} visitor + * The Visitor instance to call into while traversing. + */ +function walk(breakdown, report, visitor) { + recursiveWalk(breakdown, null, report, visitor); +} +exports.walk = walk; + +/** * diff *******************************************************************/ + +/** + * Return true if the object is a Map, false otherwise. Works with Map objects + * from other globals, unlike `instanceof`. + * + * @returns {Boolean} + */ +function isMap(obj) { + return Object.prototype.toString.call(obj) === "[object Map]"; +} + +/** + * A Visitor for computing the difference between the census report being + * traversed and the given other census. + * + * @param {Object} otherCensus + * The other census report. + */ +function DiffVisitor(otherCensus) { + // The other census we are comparing against. + this._otherCensus = otherCensus; + + // The total bytes and count of the basis census we are traversing. + this._totalBytes = 0; + this._totalCount = 0; + + // Stack maintaining the current corresponding sub-report for the other + // census we are comparing against. + this._otherCensusStack = []; + + // Stack maintaining the set of edges visited at each sub-report. + this._edgesVisited = [new Set()]; + + // The final delta census. Valid only after traversal. + this._results = null; + + // Stack maintaining the results corresponding to each sub-report we are + // currently traversing. + this._resultsStack = []; +} + +DiffVisitor.prototype = Object.create(Visitor.prototype); + +/** + * Given a report and an outgoing edge, get the edge's referent. + */ +DiffVisitor.prototype._get = function (report, edge) { + if (!report) { + return undefined; + } + return isMap(report) ? report.get(edge) : report[edge]; +}; + +/** + * Given a report, an outgoing edge, and a value, set the edge's referent to + * the given value. + */ +DiffVisitor.prototype._set = function (report, edge, val) { + if (isMap(report)) { + report.set(edge, val); + } else { + report[edge] = val; + } +}; + +/** + * @overrides Visitor.prototype.enter + */ +DiffVisitor.prototype.enter = function (breakdown, report, edge) { + const isFirstTimeEntering = this._results === null; + + const newResults = breakdown.by === "allocationStack" ? new Map() : {}; + let newOther; + + if (!this._results) { + // This is the first time we have entered a sub-report. + this._results = newResults; + newOther = this._otherCensus; + } else { + const topResults = this._resultsStack[this._resultsStack.length - 1]; + this._set(topResults, edge, newResults); + + const topOther = this._otherCensusStack[this._otherCensusStack.length - 1]; + newOther = this._get(topOther, edge); + } + + this._resultsStack.push(newResults); + this._otherCensusStack.push(newOther); + + const visited = this._edgesVisited[this._edgesVisited.length - 1]; + visited.add(edge); + this._edgesVisited.push(new Set()); +}; + +/** + * @overrides Visitor.prototype.exit + */ +DiffVisitor.prototype.exit = function (breakdown, report, edge) { + // Find all the edges in the other census report that were not traversed and + // add them to the results directly. + const other = this._otherCensusStack[this._otherCensusStack.length - 1]; + if (other) { + const visited = this._edgesVisited[this._edgesVisited.length - 1]; + const unvisited = getReportEdges(breakdown, other) + .map(e => e.edge) + .filter(e => !visited.has(e)); + const results = this._resultsStack[this._resultsStack.length - 1]; + for (let edge of unvisited) { + this._set(results, edge, this._get(other, edge)); + } + } + + this._otherCensusStack.pop(); + this._resultsStack.pop(); + this._edgesVisited.pop(); +}; + +/** + * @overrides Visitor.prototype.count + */ +DiffVisitor.prototype.count = function (breakdown, report, edge) { + const other = this._otherCensusStack[this._otherCensusStack.length - 1]; + const results = this._resultsStack[this._resultsStack.length - 1]; + + if (breakdown.count) { + this._totalCount += report.count; + } + if (breakdown.bytes) { + this._totalBytes += report.bytes; + } + + if (other) { + if (breakdown.count) { + results.count = other.count - report.count; + } + if (breakdown.bytes) { + results.bytes = other.bytes - report.bytes; + } + } else { + if (breakdown.count) { + results.count = -report.count; + } + if (breakdown.bytes) { + results.bytes = -report.bytes; + } + } +}; + +const basisTotalBytes = exports.basisTotalBytes = Symbol("basisTotalBytes"); +const basisTotalCount = exports.basisTotalCount = Symbol("basisTotalCount"); + +/** + * Get the resulting report of the difference between the traversed census + * report and the other census report. + * + * @returns {Object} + * The delta census report. + */ +DiffVisitor.prototype.results = function () { + if (!this._results) { + throw new Error("Attempt to get results before computing diff!"); + } + + if (this._resultsStack.length) { + throw new Error("Attempt to get results while still computing diff!"); + } + + this._results[basisTotalBytes] = this._totalBytes; + this._results[basisTotalCount] = this._totalCount; + + return this._results; +}; + +/** + * Take the difference between two censuses. The resulting delta report + * contains the number/size of things that are in the `endCensus` that are not + * in the `startCensus`. + * + * @param {Object} breakdown + * The breakdown used to generate both census reports. + * + * @param {Object} startCensus + * The first census report. + * + * @param {Object} endCensus + * The second census report. + * + * @returns {Object} + * A delta report mirroring the structure of the two census reports (as + * specified by the given breakdown). Has two additional properties: + * - {Number} basisTotalBytes: the total number of bytes in the start + * census. + * - {Number} basisTotalCount: the total count in the start census. + */ +function diff(breakdown, startCensus, endCensus) { + const visitor = new DiffVisitor(endCensus); + walk(breakdown, startCensus, visitor); + return visitor.results(); +} +exports.diff = diff; + +/** + * Creates a hash map mapping node IDs to its parent node. + * + * @param {CensusTreeNode} node + * @param {Object<number, TreeNode>} aggregator + * + * @return {Object<number, TreeNode>} + */ +const createParentMap = exports.createParentMap = function (node, + getId = node => node.id, + aggregator = Object.create(null)) { + if (node.children) { + for (let i = 0, length = node.children.length; i < length; i++) { + const child = node.children[i]; + aggregator[getId(child)] = node; + createParentMap(child, getId, aggregator); + } + } + + return aggregator; +}; + +const BUCKET = Object.freeze({ by: "bucket" }); + +/** + * Convert a breakdown whose leaves are { by: "count" } to an identical + * breakdown, except with { by: "bucket" } leaves. + * + * @param {Object} breakdown + * @returns {Object} + */ +exports.countToBucketBreakdown = function (breakdown) { + if (typeof breakdown !== "object" || !breakdown) { + return breakdown; + } + + if (breakdown.by === "count") { + return BUCKET; + } + + const keys = Object.keys(breakdown); + const vals = keys.reduce((vs, k) => { + vs.push(exports.countToBucketBreakdown(breakdown[k])); + return vs; + }, []); + + const result = {}; + for (let i = 0, length = keys.length; i < length; i++) { + result[keys[i]] = vals[i]; + } + + return Object.freeze(result); +}; + +/** + * A Visitor for finding report leaves by their DFS index. + */ +function GetLeavesVisitor(targetIndices) { + this._index = -1; + this._targetIndices = targetIndices; + this._leaves = []; +} + +GetLeavesVisitor.prototype = Object.create(Visitor.prototype); + +/** + * @overrides Visitor.prototype.enter + */ +GetLeavesVisitor.prototype.enter = function (breakdown, report, edge) { + this._index++; + if (this._targetIndices.has(this._index)) { + this._leaves.push(report); + } +}; + +/** + * Get the accumulated report leaves after traversal. + */ +GetLeavesVisitor.prototype.leaves = function () { + if (this._index === -1) { + throw new Error("Attempt to call `leaves` before traversing report!"); + } + return this._leaves; +}; + +/** + * Given a set of indices of leaves in a pre-order depth-first traversal of the + * given census report, return the leaves. + * + * @param {Set<Number>} indices + * @param {Object} breakdown + * @param {Object} report + * + * @returns {Array<Object>} + */ +exports.getReportLeaves = function (indices, breakdown, report) { + const visitor = new GetLeavesVisitor(indices); + walk(breakdown, report, visitor); + return visitor.leaves(); +}; + +/** + * Get a list of the individual node IDs that belong to the census report leaves + * of the given indices. + * + * @param {Set<Number>} indices + * @param {Object} breakdown + * @param {HeapSnapshot} snapshot + * + * @returns {Array<NodeId>} + */ +exports.getCensusIndividuals = function (indices, countBreakdown, snapshot) { + const bucketBreakdown = exports.countToBucketBreakdown(countBreakdown); + const bucketReport = snapshot.takeCensus({ breakdown: bucketBreakdown }); + const buckets = exports.getReportLeaves(indices, + bucketBreakdown, + bucketReport); + return flatten(buckets); +}; |