Repository: jlfwong/speedscope
Pull request #458 (2023-12-26 19:40:15)

Add hermes-specific support for the trace event format
Profiles that are transformed into the hermes trace event format are guaranteed to have specific arguments that supply metadata that is useful for debugging - namely the filename, line + col number that the function call originated from, with sourcemaps applied. This PR adds specific support for this information to the trace event importer. This means that we can have the Frame name be just the name of the function, since we know all the information we want to be displayed in the UI is captured in the frame info, which makes the traces cleaner to look at.

| Before | After |
|-----|-----|
| <img width="1728" alt="Screenshot 2023-12-26 at 2 40 01 PM" src="https://github.com/jlfwong/speedscope/assets/9957046/f9dff608-5df3-4098-b1f8-91a69185d906"> | <img width="1726" alt="Screenshot 2023-12-26 at 2 39 13 PM" src="https://github.com/jlfwong/speedscope/assets/9957046/b8ff360e-a316-4bef-8ebc-620c9ff1a998"> |
| <img width="1728" alt="Screenshot 2023-12-26 at 2 41 03 PM" src="https://github.com/jlfwong/speedscope/assets/9957046/127a49b5-458e-4ac8-934a-202e565cb20f"> | <img width="1728" alt="Screenshot 2023-12-26 at 2 41 29 PM" src="https://github.com/jlfwong/speedscope/assets/9957046/ebb285ce-6b33-4535-8e45-b9ada4e4d97f"> |

coveralls: 
[![Coverage Status](https://coveralls.io/builds/64764707/badge)](https://coveralls.io/builds/64764707)

coverage: 43.502% (+0.1%) from 43.39%
when pulling **82c741a1392dbf3038d2c8174c60edb761c52f6b on zacharyfmarion:zac/hermes-specfic-changes**
into **88f4fe610598d9dd51a97c21b632bfca58a6cd15 on jlfwong:main**.

zacharyfmarion: @jlfwong thanks for the feedback, pushed up some fixes!

Patch:
diff --git a/sample/profiles/trace-event/simple-hermes.json b/sample/profiles/trace-event/simple-hermes.json
new file mode 100644
index 0000000..628cad6
--- /dev/null
+++ b/sample/profiles/trace-event/simple-hermes.json
@@ -0,0 +1,76 @@
+[
+    {
+      "pid": 0,
+      "tid": 0,
+      "ph": "B",
+      "name": "[root]",
+      "ts": 0,
+      "args": {
+        "name": "[root]",
+        "category": "root",
+        "url": null,
+        "line": null,
+        "column": null,
+        "params": null,
+        "allocatedCategory": "root",
+        "allocatedName": "[root]"
+      }
+    },
+    {
+      "pid": 0,
+      "tid": 0,
+      "ph": "B",
+      "name": "beta",
+      "ts": 1,
+      "args": {
+        "line": 54,
+        "column": 12,
+        "funcLine": "1",
+        "funcColumn": "1",
+        "name": "beta",
+        "category": "JavaScript",
+        "parent": 1,
+        "url": "/Users/example/test_project/node_modules/metro-runtime/src/polyfills/require.js",
+        "params": null,
+        "allocatedCategory": "JavaScript",
+        "allocatedName": "beta"
+      }
+    },
+    {
+      "pid": 0,
+      "tid": 0,
+      "ph": "E",
+      "name": "beta",
+      "ts": 13,
+      "args": {
+        "line": 54,
+        "column": 12,
+        "funcLine": "1",
+        "funcColumn": "1",
+        "name": "beta",
+        "category": "JavaScript",
+        "parent": 1,
+        "url": "/Users/example/test_project/node_modules/metro-runtime/src/polyfills/require.js",
+        "params": null,
+        "allocatedCategory": "JavaScript",
+        "allocatedName": "beta"
+      }
+    },
+    {
+      "pid": 0,
+      "tid": 0,
+      "ph": "E",
+      "name": "[root]",
+      "ts": 14,
+      "args": {
+        "name": "[root]",
+        "category": "root",
+        "url": null,
+        "line": null,
+        "column": null,
+        "params": null,
+        "allocatedCategory": "root",
+        "allocatedName": "[root]"
+      }
+    }
+  ]
\ No newline at end of file
diff --git a/src/import/trace-event.ts b/src/import/trace-event.ts
index c568fd4..43b05f2 100644
--- a/src/import/trace-event.ts
+++ b/src/import/trace-event.ts
@@ -48,12 +48,46 @@ interface TraceEvent {
   cat?: string
 
   // Any arguments provided for the event. Some of the event types have required argument fields, otherwise, you can put any information you wish in here. The arguments are displayed in Trace Viewer when you view an event in the analysis section.
-  args: any
+  args?: any
 
   // A fixed color name to associate with the event. If provided, cname must be one of the names listed in trace-viewer's base color scheme's reserved color names list
   cname?: string
 }
 
+enum ExporterSource {
+  HERMES = 'HERMES',
+  UNKNOWN = 'UNKNOWN',
+}
+
+interface HermesTraceEventArgs {
+  line: number | null
+  column: number | null
+  funcLine?: string | null
+  funcColumn?: string | null
+  name: string
+  category: string
+  parent?: number
+  url: string | null
+  params: string | null
+  allocatedCategory: string
+  allocatedName: string
+}
+
+const requiredHermesArguments: Array<keyof HermesTraceEventArgs> = [
+  'line',
+  'column',
+  'name',
+  'category',
+  'url',
+  'params',
+  'allocatedCategory',
+  'allocatedName',
+]
+
+type HermesTraceEvent = TraceEvent & {
+  args: HermesTraceEventArgs
+}
+
 interface BTraceEvent extends TraceEvent {
   ph: 'B'
 }
@@ -151,7 +185,7 @@ function selectQueueToTakeFromNext(
   // to ensure it opens before we try to close it.
   //
   // Otherwise, process the 'E' queue first.
-  return frameInfoForEvent(bFront).key === frameInfoForEvent(eFront).key ? 'B' : 'E'
+  return keyForEvent(bFront) === keyForEvent(eFront) ? 'B' : 'E'
 }
 
 function convertToEventQueues(events: ImportableTraceEvent[]): [BTraceEvent[], ETraceEvent[]] {
@@ -271,16 +305,36 @@ function getThreadNamesByPidTid(events: TraceEvent[]): Map<string, string> {
   return threadNameByPidTid
 }
 
+function getEventName(event: TraceEvent): string {
+  return `${event.name || '(unnamed)'}`
+}
+
 function keyForEvent(event: TraceEvent): string {
-  let name = `${event.name || '(unnamed)'}`
+  let key = getEventName(event)
   if (event.args) {
-    name += ` ${JSON.stringify(event.args)}`
+    key += ` ${JSON.stringify(event.args)}`
   }
-  return name
+  return key
 }
 
-function frameInfoForEvent(event: TraceEvent): FrameInfo {
+function frameInfoForEvent(
+  event: TraceEvent,
+  exporterSource: ExporterSource = ExporterSource.UNKNOWN,
+): FrameInfo {
   const key = keyForEvent(event)
+
+  // In Hermes profiles we have additional guaranteed metadata we can use to
+  // more accurately populate profiles with info such as line + col number
+  if (exporterSource === ExporterSource.HERMES) {
+    return {
+      name: getEventName(event),
+      key: key,
+      file: event.args.url,
+      line: event.args.line,
+      col: event.args.column,
+    }
+  }
+
   return {
     name: key,
     key: key,
@@ -329,7 +383,11 @@ function getProfileNameByPidTid(
   return profileNamesByPidTid
 }
 
-function eventListToProfile(importableEvents: ImportableTraceEvent[], name: string): Profile {
+function eventListToProfile(
+  importableEvents: ImportableTraceEvent[],
+  name: string,
+  exporterSource: ExporterSource = ExporterSource.UNKNOWN,
+): Profile {
   // The trace event format is hard to deal with because it specifically
   // allows events to be recorded out of order, *but* event ordering is still
   // important for events with the same timestamp. Because of this, rather
@@ -355,7 +413,7 @@ function eventListToProfile(importableEvents: ImportableTraceEvent[], name: stri
   const frameStack: BTraceEvent[] = []
   const enterFrame = (b: BTraceEvent) => {
     frameStack.push(b)
-    profileBuilder.enterFrame(frameInfoForEvent(b), b.ts)
+    profileBuilder.enterFrame(frameInfoForEvent(b, exporterSource), b.ts)
   }
 
   const tryToLeaveFrame = (e: ETraceEvent) => {
@@ -364,14 +422,14 @@ function eventListToProfile(importableEvents: ImportableTraceEvent[], name: stri
     if (b == null) {
       console.warn(
         `Tried to end frame "${
-          frameInfoForEvent(e).key
+          frameInfoForEvent(e, exporterSource).key
         }", but the stack was empty. Doing nothing instead.`,
       )
       return
     }
 
-    const eFrameInfo = frameInfoForEvent(e)
-    const bFrameInfo = frameInfoForEvent(b)
+    const eFrameInfo = frameInfoForEvent(e, exporterSource)
+    const bFrameInfo = frameInfoForEvent(b, exporterSource)
 
     if (e.name !== b.name) {
       console.warn(
@@ -404,7 +462,7 @@ function eventListToProfile(importableEvents: ImportableTraceEvent[], name: stri
         // match.
         const stackTop = lastOf(frameStack)
         if (stackTop != null) {
-          const bFrameInfo = frameInfoForEvent(stackTop)
+          const bFrameInfo = frameInfoForEvent(stackTop, exporterSource)
 
           let swapped: boolean = false
 
@@ -415,7 +473,7 @@ function eventListToProfile(importableEvents: ImportableTraceEvent[], name: stri
               break
             }
 
-            const eFrameInfo = frameInfoForEvent(eEvent)
+            const eFrameInfo = frameInfoForEvent(eEvent, exporterSource)
             if (bFrameInfo.key === eFrameInfo.key) {
               // We have a match! Process this one first.
               const temp = eEventQueue[0]
@@ -463,7 +521,7 @@ function eventListToProfile(importableEvents: ImportableTraceEvent[], name: stri
   }
 
   for (let i = frameStack.length - 1; i >= 0; i--) {
-    const frame = frameInfoForEvent(frameStack[i])
+    const frame = frameInfoForEvent(frameStack[i], exporterSource)
     console.warn(`Frame "${frame.key}" was still open at end of profile. Closing automatically.`)
     profileBuilder.leaveFrame(frame, profileBuilder.getTotalWeight())
   }
@@ -544,7 +602,10 @@ function sampleListToProfile(contents: TraceWithSamples, samples: Sample[], name
   return profileBuilder.build()
 }
 
-function eventListToProfileGroup(events: TraceEvent[]): ProfileGroup {
+function eventListToProfileGroup(
+  events: TraceEvent[],
+  exporterSource: ExporterSource = ExporterSource.UNKNOWN,
+): ProfileGroup {
   const importableEvents = filterIgnoredEventTypes(events)
   const partitionedTraceEvents = partitionByPidTid(importableEvents)
   const profileNamesByPidTid = getProfileNameByPidTid(events, partitionedTraceEvents)
@@ -558,7 +619,10 @@ function eventListToProfileGroup(events: TraceEvent[]): ProfileGroup {
       throw new Error(`Could not find events for key: ${importableEventsForPidTid}`)
     }
 
-    profilePairs.push([profileKey, eventListToProfile(importableEventsForPidTid, name)])
+    profilePairs.push([
+      profileKey,
+      eventListToProfile(importableEventsForPidTid, name, exporterSource),
+    ])
   })
 
   // For now, we just sort processes by pid & tid.
@@ -641,6 +705,23 @@ function isTraceEventList(maybeEventList: any): maybeEventList is TraceEvent[] {
   return true
 }
 
+function isHermesTraceEvent(traceEventArgs: any): traceEventArgs is HermesTraceEventArgs {
+  if (!traceEventArgs) {
+    return false
+  }
+
+  return requiredHermesArguments.every(prop => prop in traceEventArgs)
+}
+
+function isHermesTraceEventList(maybeEventList: any): maybeEventList is HermesTraceEvent[] {
+  if (!isTraceEventList(maybeEventList)) return false
+
+  // We just check the first element to avoid iterating over all trace events,
+  // and asumme that if the first one is formatted like a hermes profile then
+  // all events will be
+  return isHermesTraceEvent(maybeEventList[0].args)
+}
+
 function isTraceEventObject(maybeTraceEventObject: any): maybeTraceEventObject is TraceEventObject {
   if (!('traceEvents' in maybeTraceEventObject)) return false
   return isTraceEventList(maybeTraceEventObject['traceEvents'])
@@ -669,6 +750,8 @@ export function importTraceEvents(rawProfile: Trace): ProfileGroup {
     return sampleListToProfileGroup(rawProfile)
   } else if (isTraceEventObject(rawProfile)) {
     return eventListToProfileGroup(rawProfile.traceEvents)
+  } else if (isHermesTraceEventList(rawProfile)) {
+    return eventListToProfileGroup(rawProfile, ExporterSource.HERMES)
   } else if (isTraceEventList(rawProfile)) {
     return eventListToProfileGroup(rawProfile)
   } else {


Test patch:
diff --git a/src/import/__snapshots__/trace-event.test.ts.snap b/src/import/__snapshots__/trace-event.test.ts.snap
index e135030..c416b4f 100644
--- a/src/import/__snapshots__/trace-event.test.ts.snap
+++ b/src/import/__snapshots__/trace-event.test.ts.snap
@@ -1315,6 +1315,41 @@ Object {
 }
 `;
 
+exports[`importTraceEvents simple hermes profile 1`] = `
+Object {
+  "frames": Array [
+    Frame {
+      "col": null,
+      "file": null,
+      "key": "[root] {\\"name\\":\\"[root]\\",\\"category\\":\\"root\\",\\"url\\":null,\\"line\\":null,\\"column\\":null,\\"params\\":null,\\"allocatedCategory\\":\\"root\\",\\"allocatedName\\":\\"[root]\\"}",
+      "line": null,
+      "name": "[root]",
+      "selfWeight": 2,
+      "totalWeight": 14,
+    },
+    Frame {
+      "col": 12,
+      "file": "/Users/example/test_project/node_modules/metro-runtime/src/polyfills/require.js",
+      "key": "beta {\\"line\\":54,\\"column\\":12,\\"funcLine\\":\\"1\\",\\"funcColumn\\":\\"1\\",\\"name\\":\\"beta\\",\\"category\\":\\"JavaScript\\",\\"parent\\":1,\\"url\\":\\"/Users/example/test_project/node_modules/metro-runtime/src/polyfills/require.js\\",\\"params\\":null,\\"allocatedCategory\\":\\"JavaScript\\",\\"allocatedName\\":\\"beta\\"}",
+      "line": 54,
+      "name": "beta",
+      "selfWeight": 12,
+      "totalWeight": 12,
+    },
+  ],
+  "name": "pid 0, tid 0",
+  "stacks": Array [
+    "[root] 1.00µs",
+    "[root];beta 12.00µs",
+    "[root] 1.00µs",
+  ],
+}
+`;
+
+exports[`importTraceEvents simple hermes profile: indexToView 1`] = `0`;
+
+exports[`importTraceEvents simple hermes profile: profileGroup.name 1`] = `"simple-hermes.json"`;
+
 exports[`importTraceEvents simple object 1`] = `
 Object {
   "frames": Array [
diff --git a/src/import/trace-event.test.ts b/src/import/trace-event.test.ts
index 75fe547..cc6eddf 100644
--- a/src/import/trace-event.test.ts
+++ b/src/import/trace-event.test.ts
@@ -123,6 +123,10 @@ test('importTraceEvents event reordering name match', async () => {
   await checkProfileSnapshot('./sample/profiles/trace-event/event-reordering-name-match.json')
 })
 
+test('importTraceEvents simple hermes profile', async () => {
+  await checkProfileSnapshot('./sample/profiles/trace-event/simple-hermes.json')
+})
+
 test('importTraceEvents simple profile with samples', async () => {
   await checkProfileSnapshot('./sample/profiles/trace-event/simple-with-samples.json')
 })