1 files changed, 25 insertions, 0 deletions
diff --git a/js/src/jsapi-tests/hidePointer.cpp b/js/src/jsapi-tests/hidePointer.cpp
new file mode 100644
index 0000000000..144c890359
--- /dev/null
+++ b/js/src/jsapi-tests/hidePointer.cpp
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ */
+/* 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/. */
+
+#include "mozilla/Atomics.h"
+
+// This is an attempt to hide pointer values from the C++ compiler.  This might
+// not stand up in the presence of PGO but that's probably not important.
+
+// g_hidden_pointer is public so that it's limited what the compiler can assume
+// about it, and atomic so that we don't run afoul of the compiler's UB
+// analysis.
+
+mozilla::Atomic<void*> g_hidden_pointer;
+
+// Call this to install a pointer into the global.
+
+MOZ_NEVER_INLINE void setHiddenPointer(void* p) { g_hidden_pointer = p; }
+
+// Call this to retrieve the pointer.
+
+MOZ_NEVER_INLINE void* getHiddenPointer() { return g_hidden_pointer; }