In the profile format, store a shared stringArray for all threads (#5481)

This implements the next incremental step for #3918.

The shared `stringArray` is stored at `profile.shared.stringArray`.

Sharing the string table is an easy first step - at least easier than
sharing other tables - because there are no string indexes in the URL,
so we don't need a URL upgrader for this modification.

I've also folded some basic "compacting" into this PR: Before upload, we
will remove any unused strings from the shared stringArray.

Author: mstange

docs-developer/CHANGELOG-formats.md

@@ -6,6 +6,10 @@ Note that this is not an exhaustive list. Processed profile format upgraders can
 
 ## Processed profile format
 
+### Version 56
+
+The `stringArray` is now shared across threads. The shared array is stored at `profile.shared.stringArray`.
+
 ### Version 55
 
 Changes to the `MarkerSchema` type which is used for the elements of the array at `profile.meta.markerSchema`:

src/actions/receive-profile.js

@@ -398,7 +398,7 @@ export function finalizeFullProfileView(
         const thread = profile.threads[threadIndex];
         const { samples, jsAllocations, nativeAllocations } = thread;
         hasSamples = [samples, jsAllocations, nativeAllocations].some((table) =>
-          hasUsefulSamples(table?.stack, thread)
+          hasUsefulSamples(table?.stack, thread, profile.shared)
         );
         if (hasSamples) {
           break;
@@ -799,7 +799,7 @@ export function bulkProcessSymbolicationSteps(
   symbolicationStepsPerThread: Map<ThreadIndex, SymbolicationStepInfo[]>
 ): ThunkAction<void> {
   return (dispatch, getState) => {
-    const { threads } = getProfile(getState());
+    const { threads, shared } = getProfile(getState());
     const oldFuncToNewFuncsMaps: Map<ThreadIndex, FuncToFuncsMap> = new Map();
     const symbolicatedThreads = threads.map((oldThread, threadIndex) => {
       const symbolicationSteps = symbolicationStepsPerThread.get(threadIndex);
@@ -808,6 +808,7 @@ export function bulkProcessSymbolicationSteps(
       }
       const { thread, oldFuncToNewFuncsMap } = applySymbolicationSteps(
         oldThread,
+        shared,
         symbolicationSteps
       );
       oldFuncToNewFuncsMaps.set(threadIndex, oldFuncToNewFuncsMap);
@@ -1903,7 +1904,7 @@ export function changeTabFilter(tabID: TabID | null): ThunkAction<void> {
         const thread = profile.threads[threadIndex];
         const { samples, jsAllocations, nativeAllocations } = thread;
         hasSamples = [samples, jsAllocations, nativeAllocations].some((table) =>
-          hasUsefulSamples(table?.stack, thread)
+          hasUsefulSamples(table?.stack, thread, profile.shared)
         );
         if (hasSamples) {
           break;

src/app-logic/constants.js

@@ -14,7 +14,7 @@ export const GECKO_PROFILE_VERSION = 31;
 // The current version of the "processed" profile format.
 // Please don't forget to update the processed profile format changelog in
 // `docs-developer/CHANGELOG-formats.md`.
-export const PROCESSED_PROFILE_VERSION = 55;
+export const PROCESSED_PROFILE_VERSION = 56;
 
 // The following are the margin sizes for the left and right of the timeline. Independent
 // components need to share these values.

src/components/js-tracer/Chart.js

@@ -15,6 +15,7 @@ import { JsTracerCanvas } from './Canvas';
 import {
   getCommittedRange,
   getPreviewSelection,
+  getStringTable,
 } from 'firefox-profiler/selectors/profile';
 import { selectedThreadSelectors } from 'firefox-profiler/selectors/per-thread';
 import { getSelectedThreadsKey } from 'firefox-profiler/selectors/url-state';
@@ -136,7 +137,7 @@ const JsTracerExpensiveChart = explicitConnect<
 >({
   mapStateToProps: (state, ownProps) => ({
     timeRange: getCommittedRange(state),
-    stringTable: selectedThreadSelectors.getStringTable(state),
+    stringTable: getStringTable(state),
     threadsKey: getSelectedThreadsKey(state),
     previewSelection: getPreviewSelection(state),
     jsTracerTimingRows: ensureExists(

src/profile-logic/active-tab.js

@@ -67,15 +67,20 @@ export function computeActiveTabTracks(
   const screenshots = [];
   const topmostInnerWindowIDs = getTopmostInnerWindowIDs(relevantPages);
   const innerWindowIDToPageMap = _getInnerWindowIDToPageMap(relevantPages);
+  const { stringArray } = profile.shared;
+  const stringTable = StringTable.withBackingArray(stringArray);
+
+  const screenshotNameIndex = stringTable.indexForString(
+    'CompositorScreenshot'
+  );
 
   for (
     let threadIndex = 0;
     threadIndex < profile.threads.length;
     threadIndex++
   ) {
     const thread = profile.threads[threadIndex];
-    const { markers, stringArray } = thread;
-    const stringTable = StringTable.withBackingArray(stringArray);
+    const { markers } = thread;
 
     if (thread.isMainThread) {
       // This is a main thread, there is a possibility that it can be a global
@@ -120,9 +125,6 @@ export function computeActiveTabTracks(
 
     // Check for screenshots.
     const windowIDs: Set<string> = new Set();
-    const screenshotNameIndex = stringTable.indexForString(
-      'CompositorScreenshot'
-    );
     if (screenshotNameIndex !== -1) {
       for (let markerIndex = 0; markerIndex < markers.length; markerIndex++) {
         if (markers.name[markerIndex] === screenshotNameIndex) {

src/profile-logic/data-structures.js

@@ -397,7 +397,6 @@ export function getEmptyThread(overrides?: $Shape<RawThread>): RawThread {
     markers: getEmptyRawMarkerTable(),
     stackTable: getEmptyRawStackTable(),
     frameTable: getEmptyFrameTable(),
-    stringArray: [],
     funcTable: getEmptyFuncTable(),
     resourceTable: getEmptyResourceTable(),
     nativeSymbols: getEmptyNativeSymbolTable(),
@@ -436,6 +435,9 @@ export function getEmptyProfile(): Profile {
     },
     libs: [],
     pages: [],
+    shared: {
+      stringArray: [],
+    },
     threads: [],
   };
 }

src/profile-logic/import/chrome.js

@@ -512,6 +512,8 @@ async function processTracingEvents(
   // new samples on our target interval of 500us.
   profile.meta.interval = 0.5;
 
+  const stringTable = StringTable.withBackingArray(profile.shared.stringArray);
+
   let profileEvents: (ProfileEvent | CpuProfileEvent)[] =
     (eventsByName.get('Profile'): any) || [];
 
@@ -577,13 +579,10 @@ async function processTracingEvents(
         funcTable,
         frameTable,
         stackTable,
-        stringArray,
         samples: samplesTable,
         resourceTable,
       } = thread;
 
-      const stringTable = StringTable.withBackingArray(stringArray);
-
       if (nodes) {
         const parentMap = new Map();
         for (const node of nodes) {
@@ -839,7 +838,7 @@ async function extractScreenshots(
     screenshots[0]
   );
 
-  const stringTable = StringTable.withBackingArray(thread.stringArray);
+  const stringTable = StringTable.withBackingArray(profile.shared.stringArray);
 
   const graphicsIndex = ensureExists(profile.meta.categories).findIndex(
     (category) => category.name === 'Graphics'
@@ -930,6 +929,8 @@ function extractMarkers(
     throw new Error('No "Other" category in empty profile category list');
   }
 
+  const stringTable = StringTable.withBackingArray(profile.shared.stringArray);
+
   profile.meta.markerSchema = [
     {
       name: 'EventDispatch',
@@ -996,8 +997,7 @@ function extractMarkers(
           event
         );
         const { thread } = threadInfo;
-        const { markers, stringArray } = thread;
-        const stringTable = StringTable.withBackingArray(stringArray);
+        const { markers } = thread;
         let argData: MixedObject | null = null;
         if (event.args && typeof event.args === 'object') {
           argData = (event.args: any).data || null;

src/profile-logic/import/dhat.js

@@ -180,10 +180,10 @@ export function attemptToConvertDhat(json: mixed): Profile | null {
   const profile = getEmptyProfile();
   profile.meta.product = dhat.cmd + ' (dhat)';
   profile.meta.importedFrom = `dhat`;
+  const stringTable = StringTable.withBackingArray(profile.shared.stringArray);
 
   const allocationsTable = getEmptyUnbalancedNativeAllocationsTable();
-  const { funcTable, stringArray, stackTable, frameTable } = getEmptyThread();
-  const stringTable = StringTable.withBackingArray(stringArray);
+  const { funcTable, stackTable, frameTable } = getEmptyThread();
 
   const funcKeyToFuncIndex = new Map<string, IndexIntoFuncTable>();
 
@@ -371,7 +371,6 @@ export function attemptToConvertDhat(json: mixed): Profile | null {
     thread.pid = dhat.pid;
     thread.tid = i;
     thread.name = name;
-    thread.stringArray = stringTable.getBackingArray();
 
     thread.funcTable.name = funcTable.name.slice();
     thread.funcTable.isJS = funcTable.isJS.slice();

src/profile-logic/import/simpleperf.js

@@ -223,24 +223,30 @@ class FirefoxThread {
   tid: number;
   pid: number;
 
-  stringArray = [];
-  strings = StringTable.withBackingArray(this.stringArray);
+  strings: StringTable;
 
   sampleTable: RawSamplesTable = getEmptySamplesTable();
 
-  stackTable: FirefoxSampleTable = new FirefoxSampleTable(this.strings);
-  frameTable: FirefoxFrameTable = new FirefoxFrameTable(this.strings);
-  funcTable: FirefoxFuncTable = new FirefoxFuncTable(this.strings);
-  resourceTable: FirefoxResourceTable = new FirefoxResourceTable(this.strings);
+  stackTable: FirefoxSampleTable;
+  frameTable: FirefoxFrameTable;
+  funcTable: FirefoxFuncTable;
+  resourceTable: FirefoxResourceTable;
 
   cpuClockEventId: number = -1;
 
-  constructor(thread: report.IThread) {
+  constructor(thread: report.IThread, stringTable: StringTable) {
     this.tid = thread.threadId;
     this.pid = thread.processId;
 
     this.isMainThread = thread.threadId === thread.processId;
     this.name = thread.threadName ?? '';
+
+    this.strings = stringTable;
+
+    this.stackTable = new FirefoxSampleTable(this.strings);
+    this.frameTable = new FirefoxFrameTable(this.strings);
+    this.funcTable = new FirefoxFuncTable(this.strings);
+    this.resourceTable = new FirefoxResourceTable(this.strings);
   }
 
   toJson(): RawThread {
@@ -259,7 +265,6 @@ class FirefoxThread {
       markers: getEmptyRawMarkerTable(),
       stackTable: this.stackTable.toJson(),
       frameTable: this.frameTable.toJson(),
-      stringArray: this.stringArray,
       funcTable: this.funcTable.toJson(),
       resourceTable: this.resourceTable.toJson(),
       nativeSymbols: getEmptyNativeSymbolTable(),
@@ -358,10 +363,16 @@ class FirefoxProfile {
   sampleCount: number = 0;
   lostCount: number = 0;
 
+  stringArray = [];
+  stringTable = StringTable.withBackingArray(this.stringArray);
+
   toJson(): Profile {
     return {
       meta: this.getProfileMeta(),
       libs: [],
+      shared: {
+        stringArray: this.stringArray,
+      },
       threads: this.threads.map((thread) => thread.toJson()),
     };
   }
@@ -439,7 +450,7 @@ class FirefoxProfile {
   }
 
   addThread(thread: report.IThread) {
-    const firefoxThread = new FirefoxThread(thread);
+    const firefoxThread = new FirefoxThread(thread, this.stringTable);
     this.threads.push(firefoxThread);
     this.threadMap.set(thread.threadId, firefoxThread);
   }

src/profile-logic/js-tracer.js

@@ -738,10 +738,10 @@ export function getJsTracerFixed(jsTracer: JsTracerTable): JsTracerFixed {
 export function convertJsTracerToThread(
   fromThread: RawThread,
   jsTracer: JsTracerTable,
-  categories: CategoryList
+  categories: CategoryList,
+  stringTable: StringTable
 ): RawThread {
   const jsTracerFixed = getJsTracerFixed(jsTracer);
-  const stringTable = StringTable.withBackingArray(fromThread.stringArray);
   const { thread, stackMap } = convertJsTracerToThreadWithoutSamples(
     fromThread,
     stringTable,