Bug 1061653 - Remote profiler doesn't work with old geckos, r=pbrosset

browser/devtools/profiler/profiler.js

@@ -24,6 +24,8 @@ devtools.lazyRequireGetter(this, "CATEGORIES",
   "devtools/profiler/global", true);
 devtools.lazyRequireGetter(this, "CATEGORY_MAPPINGS",
   "devtools/profiler/global", true);
+devtools.lazyRequireGetter(this, "CATEGORY_OTHER",
+  "devtools/profiler/global", true);
 devtools.lazyRequireGetter(this, "ThreadNode",
   "devtools/profiler/tree-model", true);
 devtools.lazyRequireGetter(this, "CallView",

browser/devtools/profiler/ui-profile.js

@@ -382,6 +382,7 @@ let ProfileView = {
     if (oldGraph) {
       oldGraph.destroy();
     }
+
     // Don't create a graph if there's not enough data to show.
     if (!framerateData || framerateData.length < 2) {
       return null;
@@ -620,15 +621,28 @@ let RecordingUtils = {
       if (!time || time < beginAt || time > endAt) continue;
       let blocks = [];
 
-      for (let { category } of frames) {
-        if (!category) continue;
-        let ordinal = CATEGORY_MAPPINGS[category].ordinal;
+      for (let { category: bitmask } of frames) {
+        if (!bitmask) continue;
+        let category = CATEGORY_MAPPINGS[bitmask];
 
-        if (!blocks[ordinal]) {
-          blocks[ordinal] = 1;
-        } else {
-          blocks[ordinal]++;
+        // Guard against categories that aren't found in the frontend mappings.
+        // This usually means that a new category was added in the platform,
+        // but browser/devtools/profiler/utils/global.js wasn't updated yet.
+        if (!category) {
+          category = CATEGORY_MAPPINGS[CATEGORY_OTHER];
         }
+
+        if (!blocks[category.ordinal]) {
+          blocks[category.ordinal] = 1;
+        } else {
+          blocks[category.ordinal]++;
+        }
+      }
+
+      // If no categories were found in the frames, default to using a
+      // single block using the stack depth as height.
+      if (blocks.length == 0) {
+        blocks[CATEGORY_MAPPINGS[CATEGORY_OTHER].ordinal] = frames.length;
       }
 
       categoriesData.push({
@@ -654,6 +668,12 @@ let RecordingUtils = {
    *         A data source useful for a LineGraphWidget.
    */
   plotFramerateFor: function(ticksData, beginAt, endAt) {
+    // Older Gecko versions don't have a framerate actor implementation,
+    // in which case the returned ticks data is null.
+    if (ticksData == null) {
+      return [];
+    }
+
     let framerateData = this._frameratePlotsCache.get(ticksData);
     if (framerateData == null) {
       framerateData = FramerateFront.plotFPS(ticksData, FRAMERATE_CALC_INTERVAL);

browser/devtools/profiler/utils/global.js

@@ -44,6 +44,11 @@ const CATEGORY_MAPPINGS = {
   "2048": CATEGORIES[7], // js::ProfileEntry::Category::EVENTS
 };
 
+// Human-readable "other" category bitmask. Older Geckos don't have all the
+// necessary instrumentation in the sampling profiler backend for creating
+// a categories graph, in which case we default to the "other" category.
+const CATEGORY_OTHER = 8;
+
 // Human-readable JIT category bitmask. Certain pseudo-frames in a sample,
 // like "EnterJIT", don't have any associated `cateogry` information.
 const CATEGORY_JIT = 32;
@@ -52,4 +57,5 @@ const CATEGORY_JIT = 32;
 exports.L10N = L10N;
 exports.CATEGORIES = CATEGORIES;
 exports.CATEGORY_MAPPINGS = CATEGORY_MAPPINGS;
+exports.CATEGORY_OTHER = CATEGORY_OTHER;
 exports.CATEGORY_JIT = CATEGORY_JIT;

browser/devtools/profiler/utils/shared.js

@@ -96,7 +96,7 @@ ProfilerConnection.prototype = {
     }
     // Check if we already have a grip to the `listTabs` response object
     // and, if we do, use it to get to the profiler actor.
-    else if (this._target.root) {
+    else if (this._target.root && this._target.root.profilerActor) {
       this._profiler = this._target.root.profilerActor;
       yield this._registerEventNotifications();
     }
@@ -117,7 +117,20 @@ ProfilerConnection.prototype = {
    * used in tandem with the profiler actor.
    */
   _connectMiscActors: function() {
+    // Only initialize the framerate front if the respective actor is available.
+    // Older Gecko versions don't have an existing implementation, in which case
+    // all the methods we need can be easily mocked.
+    if (this._target.form && this._target.form.framerateActor) {
     this._framerate = new FramerateFront(this._target.client, this._target.form);
+    } else {
+      this._framerate = {
+        startRecording: () => {},
+        stopRecording: () => {},
+        cancelRecording: () => {},
+        isRecording: () => false,
+        getPendingTicks: () => null
+      };
+    }
   },
 
   /**
@@ -146,11 +159,11 @@ ProfilerConnection.prototype = {
 
     // Handle requests to the framerate actor.
     if (actor == "framerate") {
+      switch (method) {
       // Only stop recording framerate if there are no other pending consumers.
       // Otherwise, for example, the next time `console.profileEnd` is called
       // there won't be any framerate data available, since we're reusing the
       // same actor for multiple overlapping recordings.
-      switch (method) {
         case "startRecording":
           this._pendingFramerateConsumers++;
           break;
@@ -158,6 +171,12 @@ ProfilerConnection.prototype = {
         case "cancelRecording":
           if (--this._pendingFramerateConsumers > 0) return;
           break;
+        // Some versions of the framerate actor don't have a 'getPendingTicks'
+        // method available, in which case it's impossible to get all the
+        // accumulated framerate data without stopping the recording. Bail out.
+        case "getPendingTicks":
+          if (method in this._framerate) break;
+          return null;
       }
       checkPendingFramerateConsumers(this);
       return this._framerate[method].apply(this._framerate, args);
@@ -387,9 +406,13 @@ ProfilerFront.prototype = {
    * Overrides the options sent to the built-in profiler module when activating,
    * such as the maximum entries count, the sampling interval etc.
    *
-   * Used in tests.
+   * Used in tests and for older backend implementations.
    */
-  _options: undefined
+  _customProfilerOptions: {
+    entries: 1000000,
+    interval: 1,
+    features: ["js"]
+  }
 };
 
 /**