1 files changed, 0 insertions, 83 deletions
diff --git a/lib/libcxx/docs/DesignDocs/ThreadingSupportAPI.rst b/lib/libcxx/docs/DesignDocs/ThreadingSupportAPI.rst
deleted file mode 100644
index 330ce74cf77..00000000000
--- a/lib/libcxx/docs/DesignDocs/ThreadingSupportAPI.rst
+++ /dev/null
@@ -1,83 +0,0 @@
-=====================
-Threading Support API
-=====================
-
-.. contents::
-   :local:
-
-Overview
-========
-
-Libc++ supports using multiple different threading models and configurations
-to implement the threading parts of libc++, including ``<thread>`` and ``<mutex>``.
-These different models provide entirely different interfaces from each
-other. To address this libc++ wraps the underlying threading API in a new and
-consistent API, which it uses internally to implement threading primitives.
-
-The ``<__threading_support>`` header is where libc++ defines its internal
-threading interface. It contains forward declarations of the internal threading
-interface as well as definitions for the interface.
-
-External Threading API and the ``<__external_threading>`` header
-================================================================
-
-In order to support vendors with custom threading API's libc++ allows the
-entire internal threading interface to be provided by an external,
-vendor provided, header.
-
-When ``_LIBCPP_HAS_THREAD_API_EXTERNAL`` is defined the ``<__threading_support>``
-header simply forwards to the ``<__external_threading>`` header (which must exist).
-It is expected that the ``<__external_threading>`` header provide the exact
-interface normally provided by ``<__threading_support>``.
-
-External Threading Library
-==========================
-
-libc++ can be compiled with its internal threading API delegating to an external
-library. Such a configuration is useful for library vendors who wish to
-distribute a thread-agnostic libc++ library, where the users of the library are
-expected to provide the implementation of the libc++ internal threading API.
-
-On a production setting, this would be achieved through a custom
-``<__external_threading>`` header, which declares the libc++ internal threading
-API but leaves out the implementation.
-
-The ``-DLIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY`` option allows building libc++ in
-such a configuration while allowing it to be tested on a platform that supports
-any of the threading systems (e.g. pthread) supported in ``__threading_support``
-header. Therefore, the main purpose of this option is to allow testing of this
-particular configuration of the library without being tied to a vendor-specific
-threading system. This option is only meant to be used by libc++ library
-developers.
-
-Threading Configuration Macros
-==============================
-
-**_LIBCPP_HAS_NO_THREADS**
-  This macro is defined when libc++ is built without threading support. It
-  should not be manually defined by the user.
-
-**_LIBCPP_HAS_THREAD_API_EXTERNAL**
-  This macro is defined when libc++ should use the ``<__external_threading>``
-  header to provide the internal threading API. This macro overrides
-  ``_LIBCPP_HAS_THREAD_API_PTHREAD``.
-
-**_LIBCPP_HAS_THREAD_API_PTHREAD**
-  This macro is defined when libc++ should use POSIX threads to implement the
-  internal threading API.
-
-**_LIBCPP_HAS_THREAD_API_WIN32**
-  This macro is defined when libc++ should use Win32 threads to implement the
-  internal threading API.
-
-**_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL**
-  This macro is defined when libc++ expects the definitions of the internal
-  threading API to be provided by an external library. When defined
-  ``<__threading_support>`` will only provide the forward declarations and
-  typedefs for the internal threading API.
-
-**_LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL**
-  This macro is used to build an external threading library using the
-  ``<__threading_support>``. Specifically it exposes the threading API
-  definitions in ``<__threading_support>`` as non-inline definitions meant to
-  be compiled into a library.