Bug 1249123 - Add telemetry for __defineGetter__/__defineSetter__ |this| values. data-review=bsmedberg r=till

js/src/builtin/Object.js

@@ -62,10 +62,13 @@ function Object_toLocaleString() {
 
 function ObjectDefineSetter(name, setter) {
     var object;
-    if (this === null || this === undefined)
+    if (this === null || this === undefined) {
+        AddContentTelemetry(JS_TELEMETRY_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED, 1);
         object = global;
-    else
+    } else {
+        AddContentTelemetry(JS_TELEMETRY_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED, 0);
         object = ToObject(this);
+    }
 
     if (!IsCallable(setter))
         ThrowTypeError(JSMSG_BAD_GETTER_OR_SETTER, "setter");
@@ -84,10 +87,13 @@ function ObjectDefineSetter(name, setter) {
 
 function ObjectDefineGetter(name, getter) {
     var object;
-    if (this === null || this === undefined)
+    if (this === null || this === undefined) {
+        AddContentTelemetry(JS_TELEMETRY_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED, 1);
         object = global;
-    else
+    } else {
+        AddContentTelemetry(JS_TELEMETRY_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED, 0);
         object = ToObject(this);
+    }
 
     if (!IsCallable(getter))
         ThrowTypeError(JSMSG_BAD_GETTER_OR_SETTER, "getter");

js/src/builtin/SelfHostingDefines.h

@@ -63,4 +63,6 @@
 #define JSITER_SYMBOLS    0x20  /* also include symbol property keys */
 #define JSITER_SYMBOLSONLY 0x40 /* exclude string property keys */
 
+#define JS_TELEMETRY_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED 25
+
 #endif

js/src/jscompartment.h

@@ -273,6 +273,14 @@ struct JSCompartment
         performanceMonitoring.unlink();
         isSystem_ = isSystem;
     }
+
+    // Used to approximate non-content code when reporting telemetry.
+    inline bool isProbablySystemOrAddonCode() const {
+        if (creationOptions_.addonIdOrNull())
+            return true;
+
+        return isSystem_;
+    }
   private:
     JSPrincipals*                principals_;
     bool                         isSystem_;

js/src/jsfriendapi.h

@@ -131,9 +131,14 @@ enum {
     JS_TELEMETRY_GC_MINOR_US,
     JS_TELEMETRY_DEPRECATED_LANGUAGE_EXTENSIONS_IN_CONTENT,
     JS_TELEMETRY_DEPRECATED_LANGUAGE_EXTENSIONS_IN_ADDONS,
-    JS_TELEMETRY_ADDON_EXCEPTIONS
+    JS_TELEMETRY_ADDON_EXCEPTIONS,
+    JS_TELEMETRY_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED,
+    JS_TELEMETRY_END
 };
 
+static_assert(JS_TELEMETRY_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED == 25,
+              "This value needs to be kept in sync with SelfHostingDefines.h");
+
 typedef void
 (*JSAccumulateTelemetryDataCallback)(int id, uint32_t sample, const char* key);
 

js/src/vm/SelfHosting.cpp

@@ -1473,6 +1473,23 @@ intrinsic_LocalTZA(JSContext* cx, unsigned argc, Value* vp)
     return true;
 }
 
+static bool
+intrinsic_AddContentTelemetry(JSContext* cx, unsigned argc, Value* vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+    MOZ_ASSERT(args.length() == 2);
+
+    int id = args[0].toInt32();
+    MOZ_ASSERT(id < JS_TELEMETRY_END);
+    MOZ_ASSERT(id >= 0);
+
+    if (!cx->compartment()->isProbablySystemOrAddonCode())
+        cx->runtime()->addTelemetry(id, args[1].toInt32());
+
+    args.rval().setUndefined();
+    return true;
+}
+
 static bool
 intrinsic_ConstructFunction(JSContext* cx, unsigned argc, Value* vp)
 {
@@ -1804,6 +1821,7 @@ static const JSFunctionSpec intrinsic_functions[] = {
     JS_FN("_FinishBoundFunctionInit", intrinsic_FinishBoundFunctionInit, 4,0),
     JS_FN("RuntimeDefaultLocale",    intrinsic_RuntimeDefaultLocale,    0,0),
     JS_FN("LocalTZA",                intrinsic_LocalTZA,                0,0),
+    JS_FN("AddContentTelemetry",     intrinsic_AddContentTelemetry,     2,0),
 
     JS_INLINABLE_FN("_IsConstructing", intrinsic_IsConstructing,        0,0,
                     IntrinsicIsConstructing),

js/xpconnect/src/XPCJSRuntime.cpp

@@ -3207,6 +3207,10 @@ AccumulateTelemetryCallback(int id, uint32_t sample, const char* key)
       case JS_TELEMETRY_ADDON_EXCEPTIONS:
         Telemetry::Accumulate(Telemetry::JS_TELEMETRY_ADDON_EXCEPTIONS, nsDependentCString(key), sample);
         break;
+      case JS_TELEMETRY_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED:
+        MOZ_ASSERT(sample == 0 || sample == 1);
+        Telemetry::Accumulate(Telemetry::JS_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED, sample);
+        break;
       default:
         MOZ_ASSERT_UNREACHABLE("Unexpected JS_TELEMETRY id");
     }

toolkit/components/telemetry/Histograms.json

@@ -524,6 +524,14 @@
     "n_values": 10,
     "description": "Use of SpiderMonkey's deprecated language extensions in add-ons: ForEach=0, DestructuringForIn=1 (obsolete), LegacyGenerator=2, ExpressionClosure=3, LetBlock=4 (obsolete), LetExpression=5 (obsolete), NoSuchMethod=6 (obsolete), FlagsArgument=7, RegExpSourceProp=8 (obsolete), RestoredRegExpStatics=9 (obsolete), BlockScopeFunRedecl=10"
   },
+  "JS_DEFINE_GETTER_SETTER_THIS_NULL_UNDEFINED": {
+    "alert_emails": ["jdemooij@mozilla.com"],
+    "bug_numbers": [1249123],
+    "expires_in_version": "55",
+    "kind": "boolean",
+    "releaseChannelCollection": "opt-out",
+    "description": "__defineGetter__ or __defineSetter__ invoked with 1 = null/undefined or 0 = everything else as |this| value"
+  },
   "XUL_CACHE_DISABLED": {
     "expires_in_version": "default",
     "kind": "flag",