1 files changed, 84 insertions, 0 deletions
diff --git a/browser/app/winlauncher/test/TestSafeThreadLocal.cpp b/browser/app/winlauncher/test/TestSafeThreadLocal.cpp
new file mode 100644
index 0000000000..31af93c375
--- /dev/null
+++ b/browser/app/winlauncher/test/TestSafeThreadLocal.cpp
@@ -0,0 +1,84 @@
+/* -*- 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 https://mozilla.org/MPL/2.0/. */
+
+#define MOZ_USE_LAUNCHER_ERROR
+
+#include "freestanding/SafeThreadLocal.h"
+
+#include "mozilla/NativeNt.h"
+#include "nsWindowsHelpers.h"
+
+#include <process.h>
+#include <stdio.h>
+
+// Need a non-inline function to bypass compiler optimization that the thread
+// local storage pointer is cached in a register before accessing a thread-local
+// variable.
+MOZ_NEVER_INLINE PVOID SwapThreadLocalStoragePointer(PVOID aNewValue) {
+  auto oldValue = mozilla::nt::RtlGetThreadLocalStoragePointer();
+  mozilla::nt::RtlSetThreadLocalStoragePointerForTestingOnly(aNewValue);
+  return oldValue;
+}
+
+static mozilla::freestanding::SafeThreadLocal<int*> gTheStorage;
+
+// Need non-inline functions to bypass compiler optimization that the thread
+// local storage pointer is cached in a register before accessing a thread-local
+// variable. See bug 1803322 for a motivating example.
+MOZ_NEVER_INLINE int* getTheStorage() { return gTheStorage.get(); }
+MOZ_NEVER_INLINE void setTheStorage(int* p) { gTheStorage.set(p); }
+
+static unsigned int __stdcall TestNonMainThread(void* aArg) {
+  for (int i = 0; i < 100; ++i) {
+    setTheStorage(&i);
+    if (getTheStorage() != &i) {
+      printf(
+          "TEST-FAILED | TestSafeThreadLocal | "
+          "A value is not correctly stored in the thread-local storage.\n");
+      return 1;
+    }
+  }
+  return 0;
+}
+
+extern "C" int wmain(int argc, wchar_t* argv[]) {
+  int dummy = 0x1234;
+
+  auto origHead = SwapThreadLocalStoragePointer(nullptr);
+  // Setting gTheStorage when TLS is null.
+  setTheStorage(&dummy);
+  SwapThreadLocalStoragePointer(origHead);
+
+  nsAutoHandle handles[8];
+  for (auto& handle : handles) {
+    handle.own(reinterpret_cast<HANDLE>(
+        ::_beginthreadex(nullptr, 0, TestNonMainThread, nullptr, 0, nullptr)));
+  }
+
+  for (int i = 0; i < 100; ++i) {
+    if (getTheStorage() != &dummy) {
+      printf(
+          "TEST-FAILED | TestSafeThreadLocal | "
+          "A value is not correctly stored in the global scope.\n");
+      return 1;
+    }
+  }
+
+  for (auto& handle : handles) {
+    ::WaitForSingleObject(handle, INFINITE);
+
+#if !defined(MOZ_ASAN)
+    // ASAN builds under Windows 11 can have unexpected thread exit codes.
+    // See bug 1798796
+    DWORD exitCode;
+    if (!::GetExitCodeThread(handle, &exitCode) || exitCode) {
+      return 1;
+    }
+#endif  // !defined(MOZ_ASAN)
+  }
+
+  return 0;
+}