[libcxx-commits] [libcxx] [libc++] Impelement P2545R4 Read-Copy Update (RCU) (PR #175451)

[Louis Dionne via libcxx-commits]

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@@ -0,0 +1,284 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RCU_RCU_DOMAIN_H
+#define _LIBCPP___RCU_RCU_DOMAIN_H
+
+#include <__config>
+
+#include <__atomic/atomic.h>
+#include <__rcu/rcu_list.h>
+
+// todo replace with internal headers
+#include <atomic>
+#include <cstdint>
+#include <map>
+#include <mutex>
+#include <vector>
+
+// todo debug
+#include <cstdio>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 26 && _LIBCPP_HAS_THREADS && _LIBCPP_HAS_EXPERIMENTAL_RCU
+
+template <class _ThreadLocal>
+class __thread_local_owner {
+  // todo put globals in experimental dylib
+  inline static thread_local map<const __thread_local_owner*, _ThreadLocal> __thread_local_instances;
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ldionne wrote:

I'm not certain what we want to use, but `<map>` is unlikely to be the right choice. I think we need to first figure out whether we're ever going to have to support multiple domains. If not, it makes no sense to use a map.

https://github.com/llvm/llvm-project/pull/175451