Bug 1633625 - move performance.mozMemory -> performance.mozMemory.gc to match the JS shell, and because performance.mozMemory.mallocBytes is deceptive when it only refers to GC-controlled malloc bytes r=jonco,smaug

Differential Revision: https://phabricator.services.mozilla.com/D74447

dom/performance/PerformanceMainThread.cpp

@@ -86,10 +86,17 @@ PerformanceMainThread::~PerformanceMainThread() {
 void PerformanceMainThread::GetMozMemory(JSContext* aCx,
                                          JS::MutableHandle<JSObject*> aObj) {
   if (!mMozMemory) {
-    mMozMemory = js::gc::NewMemoryInfoObject(aCx);
-    if (mMozMemory) {
-      mozilla::HoldJSObjects(this);
+    JS::Rooted<JSObject*> mozMemoryObj(aCx, JS_NewPlainObject(aCx));
+    JS::Rooted<JSObject*> gcMemoryObj(aCx, js::gc::NewMemoryInfoObject(aCx));
+    if (!mozMemoryObj || !gcMemoryObj) {
+      MOZ_CRASH("out of memory creating performance.mozMemory");
     }
+    if (!JS_DefineProperty(aCx, mozMemoryObj, "gc", gcMemoryObj,
+                           JSPROP_ENUMERATE)) {
+      MOZ_CRASH("out of memory creating performance.mozMemory");
+    }
+    mMozMemory = mozMemoryObj;
+    mozilla::HoldJSObjects(this);
   }
 
   aObj.set(mMozMemory);

js/src/devtools/gc-ubench/perf.js

@@ -125,12 +125,12 @@ class FrameHistory {
       var idx = sampleIndex % this._numSamples;
       this.delays[idx] = delay;
       if (features.trackingSizes) {
-        this.gcBytes[idx] = performance.mozMemory.gcBytes;
+        this.gcBytes[idx] = performance.mozMemory.gc.gcBytes;
       }
       if (features.showingGCs) {
-        this.gcs[idx] = performance.mozMemory.gcNumber;
-        this.minorGCs[idx] = performance.mozMemory.minorGCCount;
-        this.majorGCs[idx] = performance.mozMemory.majorGCCount;
+        this.gcs[idx] = performance.mozMemory.gc.gcNumber;
+        this.minorGCs[idx] = performance.mozMemory.gc.minorGCCount;
+        this.majorGCs[idx] = performance.mozMemory.gc.majorGCCount;
 
         // Previous versions lacking sliceCount will fall back to
         // assuming any GC activity was a major GC slice, even though
@@ -139,7 +139,7 @@ class FrameHistory {
         // field, it is common to load the gc-ubench index.html with
         // different browser versions.
         this.slices[idx] =
-          performance.mozMemory.sliceCount || performance.mozMemory.gcNumber;
+          performance.mozMemory.gc.sliceCount || performance.mozMemory.gc.gcNumber;
       }
     }
 

js/src/devtools/gc-ubench/ui.js

@@ -245,10 +245,10 @@ LatencyGraph.prototype.draw = function() {
 
 function MemoryGraph(ctx) {
   Graph.call(this, ctx);
-  this.worstEver = this.bestEver = performance.mozMemory.zone.gcBytes;
+  this.worstEver = this.bestEver = performance.mozMemory.gc.zone.gcBytes;
   this.limit = Math.max(
     this.worstEver,
-    performance.mozMemory.zone.gcAllocTrigger
+    performance.mozMemory.gc.zone.gcAllocTrigger
   );
 }
 
@@ -311,7 +311,7 @@ MemoryGraph.prototype.draw = function() {
     this.worstEver = worst;
     this.limit = Math.max(
       this.worstEver,
-      performance.mozMemory.zone.gcAllocTrigger
+      performance.mozMemory.gc.zone.gcAllocTrigger
     );
   }
 
@@ -322,8 +322,8 @@ MemoryGraph.prototype.draw = function() {
     "#cc1111"
   );
   this.drawHBar(
-    performance.mozMemory.zone.gcAllocTrigger,
-    `${format_bytes(performance.mozMemory.zone.gcAllocTrigger)} trigger`,
+    performance.mozMemory.gc.zone.gcAllocTrigger,
+    `${format_bytes(performance.mozMemory.gc.zone.gcAllocTrigger)} trigger`,
     "#cc11cc"
   );
 
@@ -500,7 +500,7 @@ function onload() {
   var canvas = document.getElementById("graph");
   latencyGraph = new LatencyGraph(canvas.getContext("2d"));
 
-  if (!performance.mozMemory) {
+  if (!performance.mozMemory || !performance.mozMemory.gc) {
     document.getElementById("memgraph-disabled").style.display = "block";
     document.getElementById("track-sizes-div").style.display = "none";
   }