[tools] System-analyzer: color source panel marks by event type

Change the background of source position markers based on the events
they link to.

Bug: v8:10644
Change-Id: I108d9f5670acdaf5835905c2b44648c0eaf6dbd0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2604708
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71970}

tools/system-analyzer/index.mjs

@@ -52,6 +52,13 @@ class App {
     this._startupPromise = this.runAsyncInitialize();
   }
 
+  static get allEventTypes() {
+    return new Set([
+      SourcePosition, MapLogEntry, IcLogEntry, ApiLogEntry, CodeLogEntry,
+      DeoptLogEntry
+    ]);
+  }
+
   async runAsyncInitialize() {
     await Promise.all([
       import('./view/list-panel.mjs'),
@@ -118,10 +125,7 @@ class App {
   }
 
   selectEntries(entries) {
-    const missingTypes = new Set([
-      SourcePosition, MapLogEntry, IcLogEntry, ApiLogEntry, CodeLogEntry,
-      DeoptLogEntry
-    ]);
+    const missingTypes = App.allEventTypes;
     groupBy(entries, each => each.constructor, true).forEach(group => {
       this.selectEntriesOfSingleType(group.entries);
       missingTypes.delete(group.key);

tools/system-analyzer/timeline.mjs

@@ -233,6 +233,10 @@ class Chunk {
     return this.items.length;
   }
 
+  get length() {
+    return this.items.length;
+  }
+
   yOffset(event) {
     // items[0]   == oldest event, displayed at the top of the chunk
     // items[n-1] == youngest event, displayed at the bottom of the chunk

tools/system-analyzer/view/helper.mjs

@@ -287,6 +287,23 @@ class LazyTable {
   }
 }
 
+export function gradientStopsFromGroups(
+    totalLength, maxHeight, groups, colorFn) {
+  const kMaxHeight = maxHeight === '%' ? 100 : maxHeight;
+  const kUnit = maxHeight === '%' ? '%' : 'px';
+  let increment = 0;
+  let lastHeight = 0.0;
+  const stops = [];
+  for (let group of groups) {
+    const color = colorFn(group.key);
+    increment += group.count;
+    let height = (increment / totalLength * kMaxHeight) | 0;
+    stops.push(`${color} ${lastHeight}${kUnit} ${height}${kUnit}`)
+    lastHeight = height;
+  }
+  return stops;
+}
+
 export * from '../helper.mjs';
 export {
   DOM,

tools/system-analyzer/view/script-panel.mjs

@@ -2,9 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 import {groupBy} from '../helper.mjs';
+import {App} from '../index.mjs'
 
 import {SelectRelatedEvent, ToolTipEvent} from './events.mjs';
-import {delay, DOM, formatBytes, V8CustomElement} from './helper.mjs';
+import {CSSColor, delay, DOM, formatBytes, gradientStopsFromGroups, V8CustomElement} from './helper.mjs';
 
 DOM.defineCustomElement('view/script-panel',
                         (templateText) =>
@@ -193,6 +194,18 @@ function* lineIterator(source) {
 }
 
 class LineBuilder {
+  static _colorMap = (function() {
+    const map = new Map();
+    let i = 0;
+    for (let type of App.allEventTypes) {
+      map.set(type, CSSColor.at(i++));
+    }
+    return map;
+  })();
+  static get colorMap() {
+    return this._colorMap;
+  }
+
   _script;
   _clickHandler;
   _mouseoverHandler;
@@ -248,6 +261,13 @@ class LineBuilder {
     marker.sourcePosition = sourcePosition;
     marker.onclick = this._clickHandler;
     marker.onmouseover = this._mouseoverHandler;
+
+    const entries = sourcePosition.entries;
+    const stops = gradientStopsFromGroups(
+        entries.length, '%', groupBy(entries, entry => entry.constructor),
+        type => LineBuilder.colorMap.get(type));
+    marker.style.backgroundImage = `linear-gradient(0deg,${stops.join(',')})`
+
     return marker;
   }
 }

tools/system-analyzer/view/timeline/timeline-track.mjs

@@ -5,7 +5,7 @@
 import {kChunkHeight, kChunkWidth} from '../../log/map.mjs';
 import {MapLogEntry} from '../../log/map.mjs';
 import {FocusEvent, SelectionEvent, SelectTimeEvent, SynchronizeSelectionEvent, ToolTipEvent,} from '../events.mjs';
-import {CSSColor, DOM, V8CustomElement} from '../helper.mjs';
+import {CSSColor, DOM, gradientStopsFromGroups, V8CustomElement} from '../helper.mjs';
 
 DOM.defineCustomElement('view/timeline/timeline-track',
                         (templateText) =>
@@ -147,19 +147,9 @@ DOM.defineCustomElement('view/timeline/timeline-track',
   }
 
   _createBackgroundImage(chunk) {
-    // Render the types of transitions as bar charts
-    const kHeight = chunk.height;
-    const total = chunk.size();
-    let increment = 0;
-    let lastHeight = 0.0;
-    const stops = [];
-    for (let group of chunk.getBreakdown(map => map.type)) {
-      const color = this._legend.colorForType(group.key);
-      increment += group.count;
-      let height = (increment / total * kHeight) | 0;
-      stops.push(`${color} ${lastHeight}px ${height}px`)
-      lastHeight = height;
-    }
+    const stops = gradientStopsFromGroups(
+        chunk.length, chunk.height, chunk.getBreakdown(event => event.type),
+        type => this._legend.colorForType(type));
     return `linear-gradient(0deg,${stops.join(',')})`;
   }