diff --git a/js/src/builtin/Object.cpp b/js/src/builtin/Object.cpp
index 145f1dff286..8e2689d3e16 100644
--- a/js/src/builtin/Object.cpp
+++ b/js/src/builtin/Object.cpp
@@ -272,8 +272,24 @@ js::ObjectToSource(JSContext *cx, HandleObject obj)
 JSString *
 JS_BasicObjectToString(JSContext *cx, HandleObject obj)
 {
+    // Some classes are really common, don't allocate new strings for them.
+    // The ordering below is based on the measurements in bug 966264.
+    if (obj->is<JSObject>())
+        return cx->names().objectObject;
+    if (obj->is<StringObject>())
+        return cx->names().objectString;
+    if (obj->is<ArrayObject>())
+        return cx->names().objectArray;
+    if (obj->is<JSFunction>())
+        return cx->names().objectFunction;
+    if (obj->is<NumberObject>())
+        return cx->names().objectNumber;
+
     const char *className = JSObject::className(cx, obj);
 
+    if (strcmp(className, "Window") == 0)
+        return cx->names().objectWindow;
+
     StringBuffer sb(cx);
     if (!sb.append("[object ") || !sb.appendInflated(className, strlen(className)) ||
         !sb.append("]"))
diff --git a/js/src/vm/CommonPropertyNames.h b/js/src/vm/CommonPropertyNames.h
index 0ba2d4ee561..01f5e6850a3 100644
--- a/js/src/vm/CommonPropertyNames.h
+++ b/js/src/vm/CommonPropertyNames.h
@@ -129,8 +129,14 @@
     macro(NumberFormat, NumberFormat, "NumberFormat") \
     macro(NumberFormatFormatGet, NumberFormatFormatGet, "Intl_NumberFormat_format_get") \
     macro(numeric, numeric, "numeric") \
+    macro(objectArray, objectArray, "[object Array]") \
+    macro(objectFunction, objectFunction, "[object Function]") \
     macro(objectNull, objectNull, "[object Null]") \
+    macro(objectNumber, objectNumber, "[object Number]") \
+    macro(objectObject, objectObject, "[object Object]") \
+    macro(objectString, objectString, "[object String]") \
     macro(objectUndefined, objectUndefined, "[object Undefined]") \
+    macro(objectWindow, objectWindow, "[object Window]") \
     macro(of, of, "of") \
     macro(offset, offset, "offset") \
     macro(outOfMemory, outOfMemory, "out of memory") \