[RPP] Speed up updateSourceMapEntities

When tracing gemini.google.com, it takes the Performance panel ~22.0 s
to execute updateSourceMapEntities (via resolveMappingsForProfileNodes).
With this CL, it takes ~8.7 s.

* getZeroIndexedStackTraceInEventPayload was a hot function, and it
  performed an expensive switch statement on strings for each call
  frame. That switch statement was done in a `.map`, but it is invariant
  to the mapped element, so I moved the switch statement up.
* updateSourceMapEntities actually only needs the top frame (as do many
  other callers). So I added getStackTraceTopCallFrameInEventPayload to
  perform much less work.

Bug: 444483828
Change-Id: I4bdfcc5bc9e53942a010c03822816f318ec03240
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6941582
Reviewed-by: Paul Irish <[email protected]>
Commit-Queue: Connor Clark <[email protected]>
Commit-Queue: Paul Irish <[email protected]>
Auto-Submit: Connor Clark <[email protected]>

Author: Connor Clark

front_end/models/ai_assistance/data_formatters/PerformanceTraceFormatter.ts

@@ -147,9 +147,11 @@ export class PerformanceTraceFormatter {
     function nodeToText(this: PerformanceTraceFormatter, node: Trace.Extras.TraceTree.Node): string {
       const event = node.event;
 
-      let frame = Trace.Helpers.Trace.getZeroIndexedStackTraceInEventPayload(event)?.[0];
+      let frame;
       if (Trace.Types.Events.isProfileCall(event)) {
         frame = event.callFrame;
+      } else {
+        frame = Trace.Helpers.Trace.getStackTraceTopCallFrameInEventPayload(event);
       }
 
       let source = TimelineUtils.EntryName.nameForEntry(event);

front_end/models/trace/handlers/NetworkRequestsHandler.ts

@@ -555,7 +555,7 @@ export async function finalize(): Promise<void> {
 
     // Establish initiator relationships
     const initiatorUrl = networkEvent.args.data.initiator?.url ||
-        Helpers.Trace.getZeroIndexedStackTraceInEventPayload(networkEvent)?.at(0)?.url;
+        Helpers.Trace.getStackTraceTopCallFrameInEventPayload(networkEvent)?.url;
     if (initiatorUrl) {
       const events = networkRequestEventByInitiatorUrl.get(initiatorUrl) ?? [];
       events.push(networkEvent);

front_end/models/trace/helpers/Trace.ts

@@ -471,23 +471,52 @@ export function getZeroIndexedStackTraceInEventPayload(event: Types.Events.Event
   if (!stack) {
     return null;
   }
-  return stack.map(callFrame => {
-    switch (event.name) {
-      case Types.Events.Name.SCHEDULE_STYLE_RECALCULATION:
-      case Types.Events.Name.INVALIDATE_LAYOUT:
-      case Types.Events.Name.FUNCTION_CALL:
-      case Types.Events.Name.LAYOUT:
-      case Types.Events.Name.UPDATE_LAYOUT_TREE: {
-        return makeZeroBasedCallFrame(callFrame);
+
+  switch (event.name) {
+    case Types.Events.Name.SCHEDULE_STYLE_RECALCULATION:
+    case Types.Events.Name.INVALIDATE_LAYOUT:
+    case Types.Events.Name.FUNCTION_CALL:
+    case Types.Events.Name.LAYOUT:
+    case Types.Events.Name.UPDATE_LAYOUT_TREE: {
+      return stack.map(makeZeroBasedCallFrame);
+    }
+
+    default: {
+      if (Types.Events.isUserTiming(event) || Types.Extensions.isSyntheticExtensionEntry(event)) {
+        return stack.map(makeZeroBasedCallFrame);
       }
-      default: {
-        if (Types.Events.isUserTiming(event) || Types.Extensions.isSyntheticExtensionEntry(event)) {
-          return makeZeroBasedCallFrame(callFrame);
-        }
+
+      return stack;
+    }
+  }
+}
+
+/**
+ * Same as getZeroIndexedStackTraceInEventPayload, but only returns the top call frame.
+ */
+export function getStackTraceTopCallFrameInEventPayload(event: Types.Events.Event): Types.Events.CallFrame|null {
+  const stack = stackTraceInEvent(event);
+  if (!stack || stack.length === 0) {
+    return null;
+  }
+
+  switch (event.name) {
+    case Types.Events.Name.SCHEDULE_STYLE_RECALCULATION:
+    case Types.Events.Name.INVALIDATE_LAYOUT:
+    case Types.Events.Name.FUNCTION_CALL:
+    case Types.Events.Name.LAYOUT:
+    case Types.Events.Name.UPDATE_LAYOUT_TREE: {
+      return makeZeroBasedCallFrame(stack[0]);
+    }
+
+    default: {
+      if (Types.Events.isUserTiming(event) || Types.Extensions.isSyntheticExtensionEntry(event)) {
+        return makeZeroBasedCallFrame(stack[0]);
       }
+
+      return stack[0];
     }
-    return callFrame;
-  });
+  }
 }
 
 /**

front_end/models/trace/insights/ForcedReflow.ts

@@ -153,9 +153,9 @@ function finalize(partialModel: PartialInsightModel<ForcedReflowInsightModel>):
 function getBottomCallFrameForEvent(event: Types.Events.Event, traceParsedData: Handlers.Types.HandlerData):
     Types.Events.CallFrame|Protocol.Runtime.CallFrame|null {
   const profileStackTrace = Extras.StackTraceForEvent.get(event, traceParsedData);
-  const eventStackTrace = Helpers.Trace.getZeroIndexedStackTraceInEventPayload(event);
+  const eventTopCallFrame = Helpers.Trace.getStackTraceTopCallFrameInEventPayload(event);
 
-  return profileStackTrace?.callFrames[0] ?? eventStackTrace?.[0] ?? null;
+  return profileStackTrace?.callFrames[0] ?? eventTopCallFrame ?? null;
 }
 
 export function isForcedReflowInsight(model: InsightModel): model is ForcedReflowInsightModel {

front_end/models/trace/insights/NetworkDependencyTree.ts

@@ -205,7 +205,7 @@ function isCritical(request: Types.Events.SyntheticNetworkRequest, context: Insi
   // Requests that have no initiatorRequest are typically ambiguous late-load assets.
   // Even on the off chance they were important, we don't have any parent to display for them.
   const initiatorUrl =
-      request.args.data.initiator?.url || Helpers.Trace.getZeroIndexedStackTraceInEventPayload(request)?.at(0)?.url;
+      request.args.data.initiator?.url || Helpers.Trace.getStackTraceTopCallFrameInEventPayload(request)?.url;
   if (!initiatorUrl) {
     return false;
   }

front_end/panels/timeline/TimelineUIUtils.ts

@@ -1510,9 +1510,9 @@ export class TimelineUIUtils {
       }
     }
 
-    const stackTrace = Trace.Helpers.Trace.getZeroIndexedStackTraceInEventPayload(event);
+    const hasStackTrace = Boolean(Trace.Helpers.Trace.getStackTraceTopCallFrameInEventPayload(event));
     if (Trace.Types.Events.isUserTiming(event) || Trace.Types.Extensions.isSyntheticExtensionEntry(event) ||
-        Trace.Types.Events.isProfileCall(event) || initiator || initiatorFor || stackTrace ||
+        Trace.Types.Events.isProfileCall(event) || initiator || initiatorFor || hasStackTrace ||
         parsedTrace?.data.Invalidations.invalidationsForEvent.get(event)) {
       await TimelineUIUtils.generateCauses(event, contentHelper, parsedTrace);
     }

front_end/panels/timeline/components/NetworkRequestDetails.ts

@@ -445,7 +445,7 @@ function renderInitiatedBy(
   };
   // If we have a stack trace, that is the most reliable way to get the initiator data and display a link to the source.
   if (hasStackTrace) {
-    const topFrame = Trace.Helpers.Trace.getZeroIndexedStackTraceInEventPayload(request)?.at(0) ?? null;
+    const topFrame = Trace.Helpers.Trace.getStackTraceTopCallFrameInEventPayload(request) ?? null;
     if (topFrame) {
       link = linkifier.maybeLinkifyConsoleCallFrame(target, topFrame, options);
     }

front_end/panels/timeline/utils/EntityMapper.ts

@@ -103,8 +103,7 @@ export class EntityMapper {
     // The events that don't match the source location, but that we should keep mapped to its current entity.
     const unrelatedEvents: Trace.Types.Events.Event[] = [];
     currentEntityEvents?.forEach(e => {
-      const stackTrace = Trace.Helpers.Trace.getZeroIndexedStackTraceInEventPayload(e);
-      const cf = stackTrace?.at(0);
+      const cf = Trace.Helpers.Trace.getStackTraceTopCallFrameInEventPayload(e);
 
       const matchesCallFrame = cf && Trace.Helpers.Trace.isMatchingCallFrame(cf, callFrame);
       if (matchesCallFrame) {

front_end/panels/timeline/utils/SourceMapsResolver.ts

@@ -78,11 +78,11 @@ export class SourceMapsResolver extends EventTarget {
     if (Trace.Types.Events.isProfileCall(entry)) {
       callFrame = entry.callFrame;
     } else {
-      const stackTrace = Trace.Helpers.Trace.getZeroIndexedStackTraceInEventPayload(entry);
-      if (stackTrace === null || stackTrace.length < 1) {
+      const topCallFrame = Trace.Helpers.Trace.getStackTraceTopCallFrameInEventPayload(entry);
+      if (!topCallFrame) {
         return null;
       }
-      callFrame = stackTrace[0];
+      callFrame = topCallFrame;
     }
     return SourceMapsResolver.resolvedCodeLocationForCallFrame(callFrame as Protocol.Runtime.CallFrame);
   }