1 files changed, 66 insertions, 0 deletions
diff --git a/third_party/fuchsia/repo/sdk/lib/stdcompat/include/lib/stdcompat/memory.h b/third_party/fuchsia/repo/sdk/lib/stdcompat/include/lib/stdcompat/memory.h
new file mode 100644
index 000000000..2dc3198a4
--- /dev/null
+++ b/third_party/fuchsia/repo/sdk/lib/stdcompat/include/lib/stdcompat/memory.h
@@ -0,0 +1,66 @@
+// Copyright 2020 The Fuchsia Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef LIB_STDCOMPAT_INCLUDE_LIB_STDCOMPAT_MEMORY_H_
+#define LIB_STDCOMPAT_INCLUDE_LIB_STDCOMPAT_MEMORY_H_
+
+#include <memory>
+
+#include "version.h"
+
+namespace cpp17 {
+
+#if defined(__cpp_lib_addressof_constexpr) && __cpp_lib_addressof_constexpr >= 201603L && \
+    !defined(LIB_STDCOMPAT_USE_POLYFILLS)
+
+using std::addressof;
+
+#else  // Provide constexpr polyfill for addressof.
+
+template <typename T>
+constexpr T* addressof(T& arg) noexcept {
+  return __builtin_addressof(arg);
+}
+
+template <typename T>
+const T* addressof(const T&&) = delete;
+
+#endif  // __cpp_lib_addressof_constexpr >= 201603L && !defined(LIB_STDCOMPAT_USE_POLYFILLS)
+
+}  // namespace cpp17
+
+namespace cpp20 {
+
+#if defined(__cpp_lib_to_address) && __cpp_lib_to_address >= 201711L && \
+    !defined(LIB_STDCOMPAT_USE_POLYFILLS)
+
+using std::to_address;
+
+#else  // Provide to_address polyfill.
+
+template <typename T>
+constexpr T* to_address(T* pointer) noexcept {
+  static_assert(!std::is_function<T>::value, "Cannot pass function pointers to std::to_address()");
+  return pointer;
+}
+
+// TODO(fxbug.dev/70523): This std::pointer_traits stuff is only to be bug-compatible with the
+// standard library implementations; switch back to auto when the linked bug is resolved.
+template <typename T>
+constexpr typename std::pointer_traits<T>::element_type* to_address(const T& pointer) noexcept {
+  static_assert(
+      std::is_same<decltype(pointer.operator->()),
+                   typename std::pointer_traits<T>::element_type*>::value,
+      "For compatibility with libc++ and libstdc++, operator->() must return "
+      "typename std::pointer_traits<T>::element_type*. 'Chaining' operator->() in "
+      "cpp20::to_address() will not be permitted until https://fxbug.dev/70523 is resolved.");
+
+  return to_address(pointer.operator->());
+}
+
+#endif  // __cpp_lib_to_address >= 201711L && !defined(LIB_STDCOMPAT_USE_POLYFILLS)
+
+}  // namespace cpp20
+
+#endif  // LIB_STDCOMPAT_INCLUDE_LIB_STDCOMPAT_MEMORY_H_