diff -r 000000000000 -r 6474c204b198 js/src/jsapi-tests/testGCStoreBufferRemoval.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jsapi-tests/testGCStoreBufferRemoval.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,125 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+* vim: set ts=8 sts=4 et sw=4 tw=99:
+*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifdef JSGC_GENERATIONAL
+
+#include "gc/Barrier.h"
+#include "jsapi-tests/tests.h"
+
+using namespace JS;
+using namespace js;
+
+struct AutoIgnoreRootingHazards {
+    // Force a nontrivial destructor so the compiler sees the whole RAII scope
+    static volatile int depth;
+    AutoIgnoreRootingHazards() { depth++; }
+    ~AutoIgnoreRootingHazards() { depth--; }
+};
+volatile int AutoIgnoreRootingHazards::depth = 0;
+
+BEGIN_TEST(testGCStoreBufferRemoval)
+{
+    // Sanity check - objects start in the nursery and then become tenured.
+    JS_GC(cx->runtime());
+    JS::RootedObject obj(cx, NurseryObject());
+    CHECK(js::gc::IsInsideNursery(rt, obj.get()));
+    JS_GC(cx->runtime());
+    CHECK(!js::gc::IsInsideNursery(rt, obj.get()));
+    JS::RootedObject tenuredObject(cx, obj);
+
+    // Hide the horrors herein from the static rooting analysis.
+    AutoIgnoreRootingHazards ignore;
+
+    // Test removal of store buffer entries added by RelocatablePtr<T>.
+    {
+        JSObject *badObject = reinterpret_cast<JSObject*>(1);
+        JSObject *punnedPtr = nullptr;
+        RelocatablePtrObject* relocPtr =
+            reinterpret_cast<RelocatablePtrObject*>(&punnedPtr);
+        new (relocPtr) RelocatablePtrObject;
+        *relocPtr = NurseryObject();
+        relocPtr->~RelocatablePtrObject();
+        punnedPtr = badObject;
+        JS_GC(cx->runtime());
+
+        new (relocPtr) RelocatablePtrObject;
+        *relocPtr = NurseryObject();
+        *relocPtr = tenuredObject;
+        relocPtr->~RelocatablePtrObject();
+        punnedPtr = badObject;
+        JS_GC(cx->runtime());
+
+        new (relocPtr) RelocatablePtrObject;
+        *relocPtr = NurseryObject();
+        *relocPtr = nullptr;
+        relocPtr->~RelocatablePtrObject();
+        punnedPtr = badObject;
+        JS_GC(cx->runtime());
+    }
+
+    // Test removal of store buffer entries added by RelocatableValue.
+    {
+        Value punnedValue;
+        RelocatableValue *relocValue = reinterpret_cast<RelocatableValue*>(&punnedValue);
+        new (relocValue) RelocatableValue;
+        *relocValue = ObjectValue(*NurseryObject());
+        relocValue->~RelocatableValue();
+        punnedValue = ObjectValueCrashOnTouch();
+        JS_GC(cx->runtime());
+
+        new (relocValue) RelocatableValue;
+        *relocValue = ObjectValue(*NurseryObject());
+        *relocValue = ObjectValue(*tenuredObject);
+        relocValue->~RelocatableValue();
+        punnedValue = ObjectValueCrashOnTouch();
+        JS_GC(cx->runtime());
+
+        new (relocValue) RelocatableValue;
+        *relocValue = ObjectValue(*NurseryObject());
+        *relocValue = NullValue();
+        relocValue->~RelocatableValue();
+        punnedValue = ObjectValueCrashOnTouch();
+        JS_GC(cx->runtime());
+    }
+
+    // Test removal of store buffer entries added by Heap<T>.
+    {
+        JSObject *badObject = reinterpret_cast<JSObject*>(1);
+        JSObject *punnedPtr = nullptr;
+        Heap<JSObject*>* heapPtr =
+            reinterpret_cast<Heap<JSObject*>*>(&punnedPtr);
+        new (heapPtr) Heap<JSObject*>;
+        *heapPtr = NurseryObject();
+        heapPtr->~Heap<JSObject*>();
+        punnedPtr = badObject;
+        JS_GC(cx->runtime());
+
+        new (heapPtr) Heap<JSObject*>;
+        *heapPtr = NurseryObject();
+        *heapPtr = tenuredObject;
+        heapPtr->~Heap<JSObject*>();
+        punnedPtr = badObject;
+        JS_GC(cx->runtime());
+
+        new (heapPtr) Heap<JSObject*>;
+        *heapPtr = NurseryObject();
+        *heapPtr = nullptr;
+        heapPtr->~Heap<JSObject*>();
+        punnedPtr = badObject;
+        JS_GC(cx->runtime());
+    }
+
+    return true;
+}
+
+JSObject *NurseryObject()
+{
+    return JS_NewObject(cx, nullptr, JS::NullPtr(), JS::NullPtr());
+}
+END_TEST(testGCStoreBufferRemoval)
+
+#endif