import of libc++ 6.0.0

11 files changed, 753 insertions, 41 deletions

diff --git a/lib/libcxx/docs/BuildingLibcxx.rst b/lib/libcxx/docs/BuildingLibcxx.rst
index 36866b13ef7..3dae2f41c27 100644
--- a/lib/libcxx/docs/BuildingLibcxx.rst
+++ b/lib/libcxx/docs/BuildingLibcxx.rst
@@ -49,7 +49,7 @@ The basic steps needed to build libc++ are:
    For more information about configuring libc++ see :ref:`CMake Options`.
 
    * ``make cxx`` --- will build libc++ and libc++abi.
-   * ``make check-libcxx check-libcxxabi`` --- will run the test suites.
+   * ``make check-cxx check-cxxabi`` --- will run the test suites.
 
    Shared libraries for libc++ and libc++ abi should now be present in llvm/build/lib.
    See :ref:`using an alternate libc++ installation <alternate libcxx>`
@@ -60,7 +60,7 @@ The basic steps needed to build libc++ are:
    careful not to replace it. Remember Use the CMake option ``CMAKE_INSTALL_PREFIX`` to
    select a safe place to install libc++.
 
-   * ``make install-libcxx install-libcxxabi`` --- Will install the libraries and the headers
+   * ``make install-cxx install-cxxabi`` --- Will install the libraries and the headers
 
    .. warning::
      * Replacing your systems libc++ installation could render the system non-functional.
@@ -92,6 +92,57 @@ build would look like this:
   $ make check-libcxx # optional
 
 
+Experimental Support for Windows
+--------------------------------
+
+The Windows support requires building with clang-cl as cl does not support one
+required extension: `#include_next`.  Furthermore, VS 2015 or newer (19.00) is
+required.  In the case of clang-cl, we need to specify the "MS Compatibility
+Version" as it defaults to 2014 (18.00).
+
+CMake + Visual Studio
+~~~~~~~~~~~~~~~~~~~~~
+
+Building with Visual Studio currently does not permit running tests. However,
+it is the simplest way to build.
+
+.. code-block:: batch
+
+  > cmake -G "Visual Studio 14 2015"              ^
+          -T "LLVM-vs2014"                        ^
+          -DLIBCXX_ENABLE_SHARED=YES              ^
+          -DLIBCXX_ENABLE_STATIC=NO               ^
+          -DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY=NO ^
+          \path\to\libcxx
+  > cmake --build .
+
+CMake + ninja
+~~~~~~~~~~~~~
+
+Building with ninja is required for development to enable tests.
+Unfortunately, doing so requires additional configuration as we cannot
+just specify a toolset.
+
+.. code-block:: batch
+
+  > cmake -G Ninja                                                                    ^
+          -DCMAKE_MAKE_PROGRAM=/path/to/ninja                                         ^
+          -DCMAKE_SYSTEM_NAME=Windows                                                 ^
+          -DCMAKE_C_COMPILER=clang-cl                                                 ^
+          -DCMAKE_C_FLAGS="-fms-compatibility-version=19.00 --target=i686--windows"   ^
+          -DCMAKE_CXX_COMPILER=clang-cl                                                ^
+          -DCMAKE_CXX_FLAGS="-fms-compatibility-version=19.00 --target=i686--windows" ^
+          -DLLVM_PATH=/path/to/llvm/tree                                              ^
+          -DLIBCXX_ENABLE_SHARED=YES                                                  ^
+          -DLIBCXX_ENABLE_STATIC=NO                                                   ^
+          -DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY=NO                                     ^
+          \path\to\libcxx
+  > /path/to/ninja cxx
+  > /path/to/ninja check-cxx
+
+Note that the paths specified with backward slashes must use the `\\` as the
+directory separator as clang-cl may otherwise parse the path as an argument.
+
 .. _`libc++abi`: http://libcxxabi.llvm.org/
 
 
@@ -144,20 +195,32 @@ libc++ specific options
 
   **Default**: ``OFF``
 
-  Build libc++ as a 32 bit library. Also see :option:`LLVM_BUILD_32_BITS`.
+  Build libc++ as a 32 bit library. Also see `LLVM_BUILD_32_BITS`.
 
 .. option:: LIBCXX_ENABLE_SHARED:BOOL
 
   **Default**: ``ON``
 
-  Build libc++ as a shared library. If ``OFF`` is specified then libc++ is
-  built as a static library.
+  Build libc++ as a shared library. Either `LIBCXX_ENABLE_SHARED` or
+  `LIBCXX_ENABLE_STATIC` has to be enabled.
+
+.. option:: LIBCXX_ENABLE_STATIC:BOOL
+
+  **Default**: ``ON``
+
+  Build libc++ as a static library. Either `LIBCXX_ENABLE_SHARED` or
+  `LIBCXX_ENABLE_STATIC` has to be enabled.
 
 .. option:: LIBCXX_LIBDIR_SUFFIX:STRING
 
   Extra suffix to append to the directory where libraries are to be installed.
-  This option overrides :option:`LLVM_LIBDIR_SUFFIX`.
+  This option overrides `LLVM_LIBDIR_SUFFIX`.
+
+.. option:: LIBCXX_INSTALL_PREFIX:STRING
 
+  **Default**: ``""``
+
+  Define libc++ destination prefix.
 
 .. _libc++experimental options:
 
@@ -172,7 +235,7 @@ libc++experimental Specific Options
 
 .. option:: LIBCXX_INSTALL_EXPERIMENTAL_LIBRARY:BOOL
 
-  **Default**: ``OFF``
+  **Default**: ``LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY AND LIBCXX_INSTALL_LIBRARY``
 
   Install libc++experimental.a alongside libc++.
 
@@ -227,7 +290,7 @@ ABI Library Specific Options
   libc++abi is the C++ ABI library used.
 
 
-libc++ Feature options
+libc++ Feature Options
 ----------------------
 
 .. option:: LIBCXX_ENABLE_EXCEPTIONS:BOOL
@@ -242,9 +305,32 @@ libc++ Feature options
 
   Build libc++ with run time type information.
 
+.. option:: LIBCXX_INCLUDE_BENCHMARKS:BOOL
 
-libc++ Feature options
-----------------------
+  **Default**: ``ON``
+
+  Build the libc++ benchmark tests and the Google Benchmark library needed
+  to support them.
+
+.. option:: LIBCXX_BENCHMARK_NATIVE_STDLIB:STRING
+
+  **Default**:: ``""``
+
+  **Values**:: ``libc++``, ``libstdc++``
+
+  Build the libc++ benchmark tests and Google Benchmark library against the
+  specified standard library on the platform. On linux this can be used to
+  compare libc++ to libstdc++ by building the benchmark tests against both
+  standard libraries.
+
+.. option:: LIBCXX_BENCHMARK_NATIVE_GCC_TOOLCHAIN:STRING
+
+  Use the specified GCC toolchain and standard library when building the native
+  stdlib benchmark tests.
+
+
+libc++ ABI Feature Options
+--------------------------
 
 The following options allow building libc++ for a different ABI version.
 
@@ -261,6 +347,13 @@ The following options allow building libc++ for a different ABI version.
   Build the "unstable" ABI version of libc++. Includes all ABI changing features
   on top of the current stable version.
 
+.. option:: LIBCXX_ABI_DEFINES:STRING
+
+  **Default**: ``""``
+
+  A semicolon-separated list of ABI macros to persist in the site config header.
+  See ``include/__config`` for the list of ABI macros.
+
 .. _LLVM-specific variables:
 
 LLVM-specific options
diff --git a/lib/libcxx/docs/CMakeLists.txt b/lib/libcxx/docs/CMakeLists.txt
index f63ee00a5a0..d679761a5ad 100644
--- a/lib/libcxx/docs/CMakeLists.txt
+++ b/lib/libcxx/docs/CMakeLists.txt
@@ -1,9 +1,9 @@
 
 if (LLVM_ENABLE_SPHINX)
+  include(AddSphinxTarget)
   if (SPHINX_FOUND)
-    include(AddSphinxTarget)
     if (${SPHINX_OUTPUT_HTML})
       add_sphinx_target(html libcxx)
     endif()
   endif()
-endif()
\ No newline at end of file
+endif()
diff --git a/lib/libcxx/docs/DesignDocs/AvailabilityMarkup.rst b/lib/libcxx/docs/DesignDocs/AvailabilityMarkup.rst
new file mode 100644
index 00000000000..4a85c698f23
--- /dev/null
+++ b/lib/libcxx/docs/DesignDocs/AvailabilityMarkup.rst
@@ -0,0 +1,114 @@
+===================
+Availability Markup
+===================
+
+.. contents::
+   :local:
+
+Overview
+========
+
+Libc++ is used as a system library on macOS and iOS (amongst others). In order
+for users to be able to compile a binary that is intended to be deployed to an
+older version of the platform, clang provides the
+`availability attribute <https://clang.llvm.org/docs/AttributeReference.html#availability>`_
+that can be placed on declarations to describe the lifecycle of a symbol in the
+library.
+
+Design
+======
+
+When a new feature is introduced that requires dylib support, a macro should be
+created in include/__config to mark this feature as unavailable for all the
+systems. For example::
+
+    // Define availability macros.
+    #if defined(_LIBCPP_USE_AVAILABILITY_APPLE)
+    #define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS __attribute__((unavailable))
+    #else  if defined(_LIBCPP_USE_AVAILABILITY_SOME_OTHER_VENDOR)
+    #define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS __attribute__((unavailable))
+	#else
+    #define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS
+    #endif
+
+When the library is updated by the platform vendor, the markup can be updated.
+For example::
+
+    #define _LIBCPP_AVAILABILITY_SHARED_MUTEX                                  \
+      __attribute__((availability(macosx,strict,introduced=10.12)))            \
+      __attribute__((availability(ios,strict,introduced=10.0)))                \
+      __attribute__((availability(tvos,strict,introduced=10.0)))               \
+      __attribute__((availability(watchos,strict,introduced=3.0)))
+
+In the source code, the macro can be added on a class if the full class requires
+type info from the library for example::
+
+	_LIBCPP_BEGIN_NAMESPACE_EXPERIMENTAL
+	class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS bad_optional_access
+	    : public std::logic_error {
+
+or on a particular symbol:
+
+    _LIBCPP_OVERRIDABLE_FUNC_VIS _LIBCPP_AVAILABILITY_SIZED_NEW_DELETE void  operator delete(void* __p, std::size_t __sz) _NOEXCEPT;
+
+
+Testing
+=======
+
+Some parameters can be passed to lit to run the test-suite and exercising the
+availability.
+
+* The `platform` parameter controls the deployement target. For example lit can
+  be invoked with `--param=platform=macosx10.8`. Default is the current host.
+* The `use_system_cxx_lib` parameter indicates to use another library than the
+  just built one. Invoking lit with `--param=use_system_cxx_lib=true` will run
+  the test-suite against the host system library. Alternatively a path to the
+  directory containing a specific prebuilt libc++ can be used, for example:
+  `--param=use_system_cxx_lib=/path/to/macOS/10.8/`.
+* The `with_availability` boolean parameter enables the availability markup.
+
+Tests can be marked as XFAIL based on multiple features made available by lit:
+
+
+* if either `use_system_cxx_lib` or  `with_availability` is passed to lit,
+  assuming `--param=platform=macosx10.8` is passed as well the following
+  features will be available:
+
+  - availability
+  - availability=x86_64
+  - availability=macosx
+  - availability=x86_64-macosx
+  - availability=x86_64-apple-macosx10.8
+  - availability=macosx10.8
+
+  This feature is used to XFAIL a test that *is* using a class of a method marked
+  as unavailable *and* that is expected to *fail* if deployed on an older system.
+
+* if `use_system_cxx_lib` is passed to lit, the following features will also
+  be available:
+
+  - with_system_cxx_lib
+  - with_system_cxx_lib=x86_64
+  - with_system_cxx_lib=macosx
+  - with_system_cxx_lib=x86_64-macosx
+  - with_system_cxx_lib=x86_64-apple-macosx10.8
+  - with_system_cxx_lib=macosx10.8
+
+  This feature is used to XFAIL a test that is *not* using a class of a method
+  marked as unavailable *but* that is expected to fail if deployed on an older
+  system. For example if we know that it exhibits a but in the libc on a
+  particular system version.
+
+* if `with_availability` is passed to lit, the following features will also
+  be available:
+
+  - availability_markup
+  - availability_markup=x86_64
+  - availability_markup=macosx
+  - availability_markup=x86_64-macosx
+  - availability_markup=x86_64-apple-macosx10.8
+  - availability_markup=macosx10.8
+
+  This feature is used to XFAIL a test that *is* using a class of a method
+  marked as unavailable *but* that is expected to *pass* if deployed on an older
+  system. For example if it is using a symbol in a statically evaluated context.
diff --git a/lib/libcxx/docs/DesignDocs/DebugMode.rst b/lib/libcxx/docs/DesignDocs/DebugMode.rst
new file mode 100644
index 00000000000..3b997d44607
--- /dev/null
+++ b/lib/libcxx/docs/DesignDocs/DebugMode.rst
@@ -0,0 +1,100 @@
+==========
+Debug Mode
+==========
+
+.. contents::
+   :local:
+
+.. _using-debug-mode:
+
+Using Debug Mode
+================
+
+Libc++ provides a debug mode that enables assertions meant to detect incorrect
+usage of the standard library. By default these assertions are disabled but
+they can be enabled using the ``_LIBCPP_DEBUG`` macro.
+
+**_LIBCPP_DEBUG** Macro
+-----------------------
+
+**_LIBCPP_DEBUG**:
+  This macro is used to enable assertions and iterator debugging checks within
+  libc++. By default it is undefined.
+
+  **Values**: ``0``, ``1``
+
+  Defining ``_LIBCPP_DEBUG`` to ``0`` or greater enables most of libc++'s
+  assertions. Defining ``_LIBCPP_DEBUG`` to ``1`` enables "iterator debugging"
+  which provides additional assertions about the validity of iterators used by
+  the program.
+
+  Note that this option has no effect on libc++'s ABI
+
+**_LIBCPP_DEBUG_USE_EXCEPTIONS**:
+  When this macro is defined ``_LIBCPP_ASSERT`` failures throw
+  ``__libcpp_debug_exception`` instead of aborting. Additionally this macro
+  disables exception specifications on functions containing ``_LIBCPP_ASSERT``
+  checks. This allows assertion failures to correctly throw through these
+  functions.
+
+Handling Assertion Failures
+---------------------------
+
+When a debug assertion fails the assertion handler is called via the
+``std::__libcpp_debug_function`` function pointer. It is possible to override
+this function pointer using a different handler function. Libc++ provides two
+different assertion handlers, the default handler
+``std::__libcpp_abort_debug_handler`` which aborts the program, and
+``std::__libcpp_throw_debug_handler`` which throws an instance of
+``std::__libcpp_debug_exception``. Libc++ can be changed to use the throwing
+assertion handler as follows:
+
+.. code-block:: cpp
+
+  #define _LIBCPP_DEBUG 1
+  #include <string>
+  int main() {
+    std::__libcpp_debug_function = std::__libcpp_throw_debug_function;
+    try {
+      std::string::iterator bad_it;
+      std::string str("hello world");
+      str.insert(bad_it, '!'); // causes debug assertion
+    } catch (std::__libcpp_debug_exception const&) {
+      return EXIT_SUCCESS;
+    }
+    return EXIT_FAILURE;
+  }
+
+Debug Mode Checks
+=================
+
+Libc++'s debug mode offers two levels of checking. The first enables various
+precondition checks throughout libc++. The second additionally enables
+"iterator debugging" which checks the validity of iterators used by the program.
+
+Basic Checks
+============
+
+These checks are enabled when ``_LIBCPP_DEBUG`` is defined to either 0 or 1.
+
+The following checks are enabled by ``_LIBCPP_DEBUG``:
+
+  * FIXME: Update this list
+
+Iterator Debugging Checks
+=========================
+
+These checks are enabled when ``_LIBCPP_DEBUG`` is defined to 1.
+
+The following containers and STL classes support iterator debugging:
+
+  * ``std::string``
+  * ``std::vector<T>`` (``T != bool``)
+  * ``std::list``
+  * ``std::unordered_map``
+  * ``std::unordered_multimap``
+  * ``std::unordered_set``
+  * ``std::unordered_multiset``
+
+The remaining containers do not currently support iterator debugging.
+Patches welcome.
diff --git a/lib/libcxx/docs/DesignDocs/ThreadingSupportAPI.rst b/lib/libcxx/docs/DesignDocs/ThreadingSupportAPI.rst
new file mode 100644
index 00000000000..556c45b7e1f
--- /dev/null
+++ b/lib/libcxx/docs/DesignDocs/ThreadingSupportAPI.rst
@@ -0,0 +1,79 @@
+=====================
+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_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.
diff --git a/lib/libcxx/docs/DesignDocs/VisibilityMacros.rst b/lib/libcxx/docs/DesignDocs/VisibilityMacros.rst
new file mode 100644
index 00000000000..993ce2cca5f
--- /dev/null
+++ b/lib/libcxx/docs/DesignDocs/VisibilityMacros.rst
@@ -0,0 +1,163 @@
+========================
+Symbol Visibility Macros
+========================
+
+.. contents::
+   :local:
+
+Overview
+========
+
+Libc++ uses various "visibility" macros in order to provide a stable ABI in
+both the library and the headers. These macros work by changing the
+visibility and inlining characteristics of the symbols they are applied to.
+
+Visibility Macros
+=================
+
+**_LIBCPP_HIDDEN**
+  Mark a symbol as hidden so it will not be exported from shared libraries.
+
+**_LIBCPP_FUNC_VIS**
+  Mark a symbol as being exported by the libc++ library. This attribute must
+  be applied to the declaration of all functions exported by the libc++ dylib.
+
+**_LIBCPP_EXTERN_VIS**
+  Mark a symbol as being exported by the libc++ library. This attribute may
+  only be applied to objects defined in the libc++ library. On Windows this
+  macro applies `dllimport`/`dllexport` to the symbol. On all other platforms
+  this macro has no effect.
+
+**_LIBCPP_OVERRIDABLE_FUNC_VIS**
+  Mark a symbol as being exported by the libc++ library, but allow it to be
+  overridden locally. On non-Windows, this is equivalent to `_LIBCPP_FUNC_VIS`.
+  This macro is applied to all `operator new` and `operator delete` overloads.
+
+  **Windows Behavior**: Any symbol marked `dllimport` cannot be overridden
+  locally, since `dllimport` indicates the symbol should be bound to a separate
+  DLL. All `operator new` and `operator delete` overloads are required to be
+  locally overridable, and therefore must not be marked `dllimport`. On Windows,
+  this macro therefore expands to `__declspec(dllexport)` when building the
+  library and has an empty definition otherwise.
+
+**_LIBCPP_INLINE_VISIBILITY**
+  Mark a function as hidden and force inlining whenever possible.
+
+**_LIBCPP_ALWAYS_INLINE**
+  A synonym for `_LIBCPP_INLINE_VISIBILITY`
+
+**_LIBCPP_TYPE_VIS**
+  Mark a type's typeinfo, vtable and members as having default visibility.
+  This attribute cannot be used on class templates.
+
+**_LIBCPP_TEMPLATE_VIS**
+  Mark a type's typeinfo and vtable as having default visibility.
+  This macro has no effect on the visibility of the type's member functions.
+
+  **GCC Behavior**: GCC does not support Clang's `type_visibility(...)`
+  attribute. With GCC the `visibility(...)` attribute is used and member
+  functions are affected.
+
+  **Windows Behavior**: DLLs do not support dllimport/export on class templates.
+  The macro has an empty definition on this platform.
+
+
+**_LIBCPP_ENUM_VIS**
+  Mark the typeinfo of an enum as having default visibility. This attribute
+  should be applied to all enum declarations.
+
+  **Windows Behavior**: DLLs do not support importing or exporting enumeration
+  typeinfo. The macro has an empty definition on this platform.
+
+  **GCC Behavior**: GCC un-hides the typeinfo for enumerations by default, even
+  if `-fvisibility=hidden` is specified. Additionally applying a visibility
+  attribute to an enum class results in a warning. The macro has an empty
+  definition with GCC.
+
+**_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS**
+  Mark the member functions, typeinfo, and vtable of the type named in
+  a `_LIBCPP_EXTERN_TEMPLATE` declaration as being exported by the libc++ library.
+  This attribute must be specified on all extern class template declarations.
+
+  This macro is used to override the `_LIBCPP_TEMPLATE_VIS` attribute
+  specified on the primary template and to export the member functions produced
+  by the explicit instantiation in the dylib.
+
+  **GCC Behavior**: GCC ignores visibility attributes applied the type in
+  extern template declarations and applying an attribute results in a warning.
+  However since `_LIBCPP_TEMPLATE_VIS` is the same as
+  `__attribute__((visibility("default"))` the visibility is already correct.
+  The macro has an empty definition with GCC.
+
+  **Windows Behavior**: `extern template` and `dllexport` are fundamentally
+  incompatible *on a class template* on Windows; the former suppresses
+  instantiation, while the latter forces it. Specifying both on the same
+  declaration makes the class template be instantiated, which is not desirable
+  inside headers. This macro therefore expands to `dllimport` outside of libc++
+  but nothing inside of it (rather than expanding to `dllexport`); instead, the
+  explicit instantiations themselves are marked as exported. Note that this
+  applies *only* to extern *class* templates. Extern *function* templates obey
+  regular import/export semantics, and applying `dllexport` directly to the
+  extern template declaration (i.e. using `_LIBCPP_FUNC_VIS`) is the correct
+  thing to do for them.
+
+**_LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS**
+  Mark the member functions, typeinfo, and vtable of an explicit instantiation
+  of a class template as being exported by the libc++ library. This attribute
+  must be specified on all class template explicit instantiations.
+
+  It is only necessary to mark the explicit instantiation itself (as opposed to
+  the extern template declaration) as exported on Windows, as discussed above.
+  On all other platforms, this macro has an empty definition.
+
+**_LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS**
+  Mark a symbol as hidden so it will not be exported from shared libraries. This
+  is intended specifically for method templates of either classes marked with
+  `_LIBCPP_TYPE_VIS` or classes with an extern template instantiation
+  declaration marked with `_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS`.
+
+  When building libc++ with hidden visibility, we want explicit template
+  instantiations to export members, which is consistent with existing Windows
+  behavior. We also want classes annotated with `_LIBCPP_TYPE_VIS` to export
+  their members, which is again consistent with existing Windows behavior.
+  Both these changes are necessary for clients to be able to link against a
+  libc++ DSO built with hidden visibility without encountering missing symbols.
+
+  An unfortunate side effect, however, is that method templates of classes
+  either marked `_LIBCPP_TYPE_VIS` or with extern template instantiation
+  declarations marked with `_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS` also get default
+  visibility when instantiated. These methods are often implicitly instantiated
+  inside other libraries which use the libc++ headers, and will therefore end up
+  being exported from those libraries, since those implicit instantiations will
+  receive default visibility. This is not acceptable for libraries that wish to
+  control their visibility, and led to PR30642.
+
+  Consequently, all such problematic method templates are explicitly marked
+  either hidden (via this macro) or inline, so that they don't leak into client
+  libraries. The problematic methods were found by running
+  `bad-visibility-finder <https://github.com/smeenai/bad-visibility-finder>`_
+  against the libc++ headers after making `_LIBCPP_TYPE_VIS` and
+  `_LIBCPP_EXTERN_TEMPLATE_TYPE_VIS` expand to default visibility.
+
+**_LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY**
+  Mark a member function of a class template as visible and always inline. This
+  macro should only be applied to member functions of class templates that are
+  externally instantiated. It is important that these symbols are not marked
+  as hidden as that will prevent the dylib definition from being found.
+
+  This macro is used to maintain ABI compatibility for symbols that have been
+  historically exported by the libc++ library but are now marked inline.
+
+**_LIBCPP_EXCEPTION_ABI**
+  Mark the member functions, typeinfo, and vtable of the type as being exported
+  by the libc++ library. This macro must be applied to all *exception types*.
+  Exception types should be defined directly in namespace `std` and not the
+  versioning namespace. This allows throwing and catching some exception types
+  between libc++ and libstdc++.
+
+Links
+=====
+
+* `[cfe-dev] Visibility in libc++ - 1 <http://lists.llvm.org/pipermail/cfe-dev/2013-July/030610.html>`_
+* `[cfe-dev] Visibility in libc++ - 2 <http://lists.llvm.org/pipermail/cfe-dev/2013-August/031195.html>`_
+* `[libcxx] Visibility fixes for Windows <http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20130805/085461.html>`_
diff --git a/lib/libcxx/docs/Makefile.sphinx b/lib/libcxx/docs/Makefile.sphinx
index 2ca1e4d3faf..ae37a34b54e 100644
--- a/lib/libcxx/docs/Makefile.sphinx
+++ b/lib/libcxx/docs/Makefile.sphinx
@@ -5,7 +5,7 @@
 # out-of-tree builds.
 
 # You can set these variables from the command line.
-SPHINXOPTS    =
+SPHINXOPTS    = -n -W
 SPHINXBUILD   = sphinx-build
 PAPER         =
 BUILDDIR      = _build
diff --git a/lib/libcxx/docs/TestingLibcxx.rst b/lib/libcxx/docs/TestingLibcxx.rst
index 9226ae17023..43c0684dc7d 100644
--- a/lib/libcxx/docs/TestingLibcxx.rst
+++ b/lib/libcxx/docs/TestingLibcxx.rst
@@ -98,56 +98,64 @@ configuration. Passing the option on the command line will override the default.
 
 .. program:: lit
 
-.. option:: --cxx_under_test=<path/to/compiler>
+.. option:: cxx_under_test=<path/to/compiler>
 
   Specify the compiler used to build the tests.
 
+.. option:: cxx_stdlib_under_test=<stdlib name>
+
+  **Values**: libc++, libstdc++
+
+  Specify the C++ standard library being tested. Unless otherwise specified
+  libc++ is used. This option is intended to allow running the libc++ test
+  suite against other standard library implementations.
+
 .. option:: std=<standard version>
 
-  **Values**: c++98, c++03, c++11, c++14, c++1z
+  **Values**: c++98, c++03, c++11, c++14, c++17, c++2a
 
   Change the standard version used when building the tests.
 
-.. option:: --libcxx_site_config=<path/to/lit.site.cfg>
+.. option:: libcxx_site_config=<path/to/lit.site.cfg>
 
   Specify the site configuration to use when running the tests.  This option
-  overrides the enviroment variable LIBCXX_SITE_CONFIG.
+  overrides the environment variable LIBCXX_SITE_CONFIG.
 
-.. option:: --libcxx_headers=<path/to/headers>
+.. option:: cxx_headers=<path/to/headers>
 
-  Specify the libc++ headers that are tested. By default the headers in the
-  source tree are used.
+  Specify the c++ standard library headers that are tested. By default the
+  headers in the source tree are used.
 
-.. option:: --cxx_library_root=<path/to/lib/>
+.. option:: cxx_library_root=<path/to/lib/>
 
   Specify the directory of the libc++ library to be tested. By default the
   library folder of the build directory is used. This option cannot be used
-  when use_system_lib is provided.
+  when use_system_cxx_lib is provided.
 
 
-.. option:: --cxx_runtime_root=<path/to/lib/>
+.. option:: cxx_runtime_root=<path/to/lib/>
 
   Specify the directory of the libc++ library to use at runtime. This directory
   is not added to the linkers search path. This can be used to compile tests
   against one version of libc++ and run them using another. The default value
   for this option is `cxx_library_root`. This option cannot be used
-  when use_system_lib is provided.
+  when use_system_cxx_lib is provided.
 
-.. option:: --use_system_lib=<bool>
+.. option:: use_system_cxx_lib=<bool>
 
   **Default**: False
 
   Enable or disable testing against the installed version of libc++ library.
   Note: This does not use the installed headers.
 
-.. option:: --use_lit_shell=<bool>
+.. option:: use_lit_shell=<bool>
 
   Enable or disable the use of LIT's internal shell in ShTests. If the
   environment variable LIT_USE_INTERNAL_SHELL is present then that is used as
   the default value. Otherwise the default value is True on Windows and False
   on every other platform.
 
-.. option:: --no_default_flags=<bool>
+.. option:: no_default_flags=<bool>
 
   **Default**: False
 
@@ -155,16 +163,16 @@ configuration. Passing the option on the command line will override the default.
   option is used only flags specified using the compile_flags and link_flags
   will be used.
 
-.. option:: --compile_flags="<list-of-args>"
+.. option:: compile_flags="<list-of-args>"
 
   Specify additional compile flags as a space delimited string.
   Note: This options should not be used to change the standard version used.
 
-.. option:: --link_flags="<list-of-args>"
+.. option:: link_flags="<list-of-args>"
 
   Specify additional link flags as a space delimited string.
 
-.. option:: --debug_level=<level>
+.. option:: debug_level=<level>
 
   **Values**: 0, 1
 
@@ -191,10 +199,68 @@ Environment Variables
 .. envvar:: LIBCXX_SITE_CONFIG=<path/to/lit.site.cfg>
 
   Specify the site configuration to use when running the tests.
-  Also see :option:`libcxx_site_config`.
+  Also see `libcxx_site_config`.
 
 .. envvar:: LIBCXX_COLOR_DIAGNOSTICS
 
   If ``LIBCXX_COLOR_DIAGNOSTICS`` is defined then the test suite will attempt
   to use color diagnostic outputs from the compiler.
-  Also see :option:`color_diagnostics`.
+  Also see `color_diagnostics`.
+
+Benchmarks
+==========
+
+Libc++ contains benchmark tests separately from the test of the test suite.
+The benchmarks are written using the `Google Benchmark`_ library, a copy of which
+is stored in the libc++ repository.
+
+For more information about using the Google Benchmark library see the
+`official documentation <https://github.com/google/benchmark>`_.
+
+.. _`Google Benchmark`: https://github.com/google/benchmark
+
+Building Benchmarks
+-------------------
+
+The benchmark tests are not built by default. The benchmarks can be built using
+the ``cxx-benchmarks`` target.
+
+An example build would look like:
+
+.. code-block:: bash
+
+  $ cd build
+  $ cmake [options] <path to libcxx sources>
+  $ make cxx-benchmarks
+
+This will build all of the benchmarks under ``<libcxx-src>/benchmarks`` to be
+built against the just-built libc++. The compiled tests are output into
+``build/benchmarks``.
+
+The benchmarks can also be built against the platforms native standard library
+using the ``-DLIBCXX_BUILD_BENCHMARKS_NATIVE_STDLIB=ON`` CMake option. This
+is useful for comparing the performance of libc++ to other standard libraries.
+The compiled benchmarks are named ``<test>.libcxx.out`` if they test libc++ and
+``<test>.native.out`` otherwise.
+
+Also See:
+
+  * :ref:`Building Libc++ <build instructions>`
+  * :ref:`CMake Options`
+
+Running Benchmarks
+------------------
+
+The benchmarks must be run manually by the user. Currently there is no way
+to run them as part of the build.
+
+For example:
+
+.. code-block:: bash
+
+  $ cd build/benchmarks
+  $ make cxx-benchmarks
+  $ ./algorithms.libcxx.out # Runs all the benchmarks
+  $ ./algorithms.libcxx.out --benchmark_filter=BM_Sort.* # Only runs the sort benchmarks
+
+For more information about running benchmarks see `Google Benchmark`_.
diff --git a/lib/libcxx/docs/UsingLibcxx.rst b/lib/libcxx/docs/UsingLibcxx.rst
index 514ed14b746..f54234d6aa3 100644
--- a/lib/libcxx/docs/UsingLibcxx.rst
+++ b/lib/libcxx/docs/UsingLibcxx.rst
@@ -123,3 +123,97 @@ supported by libc++ they may be useful to users.
 Known 3rd Party Implementations Include:
 
 * `Koutheir's libc++ pretty-printers <https://github.com/koutheir/libcxx-pretty-printers>`_.
+
+
+Libc++ Configuration Macros
+===========================
+
+Libc++ provides a number of configuration macros which can be used to enable
+or disable extended libc++ behavior, including enabling "debug mode" or
+thread safety annotations.
+
+**_LIBCPP_DEBUG**:
+  See :ref:`using-debug-mode` for more information.
+
+**_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS**:
+  This macro is used to enable -Wthread-safety annotations on libc++'s
+  ``std::mutex`` and ``std::lock_guard``. By default these annotations are
+  disabled and must be manually enabled by the user.
+
+**_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS**:
+  This macro is used to disable all visibility annotations inside libc++.
+  Defining this macro and then building libc++ with hidden visibility gives a
+  build of libc++ which does not export any symbols, which can be useful when
+  building statically for inclusion into another library.
+
+**_LIBCPP_DISABLE_EXTERN_TEMPLATE**:
+  This macro is used to disable extern template declarations in the libc++
+  headers. The intended use case is for clients who wish to use the libc++
+  headers without taking a dependency on the libc++ library itself.
+
+**_LIBCPP_ENABLE_TUPLE_IMPLICIT_REDUCED_ARITY_EXTENSION**:
+  This macro is used to re-enable an extension in `std::tuple` which allowed
+  it to be implicitly constructed from fewer initializers than contained
+  elements. Elements without an initializer are default constructed. For example:
+
+  .. code-block:: cpp
+
+    std::tuple<std::string, int, std::error_code> foo() {
+      return {"hello world", 42}; // default constructs error_code
+    }
+
+
+  Since libc++ 4.0 this extension has been disabled by default. This macro
+  may be defined to re-enable it in order to support existing code that depends
+  on the extension. New use of this extension should be discouraged.
+  See `PR 27374 <http://llvm.org/PR27374>`_ for more information.
+
+  Note: The "reduced-arity-initialization" extension is still offered but only
+  for explicit conversions. Example:
+
+  .. code-block:: cpp
+
+    auto foo() {
+      using Tup = std::tuple<std::string, int, std::error_code>;
+      return Tup{"hello world", 42}; // explicit constructor called. OK.
+    }
+
+**_LIBCPP_DISABLE_ADDITIONAL_DIAGNOSTICS**:
+  This macro disables the additional diagnostics generated by libc++ using the
+  `diagnose_if` attribute. These additional diagnostics include checks for:
+
+    * Giving `set`, `map`, `multiset`, `multimap` a comparator which is not
+      const callable.
+
+**_LIBCPP_NO_VCRUNTIME**:
+  Microsoft's C and C++ headers are fairly entangled, and some of their C++
+  headers are fairly hard to avoid. In particular, `vcruntime_new.h` gets pulled
+  in from a lot of other headers and provides definitions which clash with
+  libc++ headers, such as `nothrow_t` (note that `nothrow_t` is a struct, so
+  there's no way for libc++ to provide a compatible definition, since you can't
+  have multiple definitions).
+
+  By default, libc++ solves this problem by deferring to Microsoft's vcruntime
+  headers where needed. However, it may be undesirable to depend on vcruntime
+  headers, since they may not always be available in cross-compilation setups,
+  or they may clash with other headers. The `_LIBCPP_NO_VCRUNTIME` macro
+  prevents libc++ from depending on vcruntime headers. Consequently, it also
+  prevents libc++ headers from being interoperable with vcruntime headers (from
+  the aforementioned clashes), so users of this macro are promising to not
+  attempt to combine libc++ headers with the problematic vcruntime headers. This
+  macro also currently prevents certain `operator new`/`operator delete`
+  replacement scenarios from working, e.g. replacing `operator new` and
+  expecting a non-replaced `operator new[]` to call the replaced `operator new`.
+
+C++17 Specific Configuration Macros
+-----------------------------------
+**_LIBCPP_ENABLE_CXX17_REMOVED_FEATURES**:
+  This macro is used to re-enable all the features removed in C++17. The effect
+  is equivalent to manually defining each macro listed below.
+
+**_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS**:
+  This macro is used to re-enable the `set_unexpected`, `get_unexpected`, and
+  `unexpected` functions, which were removed in C++17.
+
+**_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR**:
+  This macro is used to re-enable `std::auto_ptr` in C++17.
diff --git a/lib/libcxx/docs/conf.py b/lib/libcxx/docs/conf.py
index e385406b992..bb231ac3e35 100644
--- a/lib/libcxx/docs/conf.py
+++ b/lib/libcxx/docs/conf.py
@@ -40,16 +40,16 @@ master_doc = 'index'
 
 # General information about the project.
 project = u'libc++'
-copyright = u'2011-2016, LLVM Project'
+copyright = u'2011-2017, LLVM Project'
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.
 #
 # The short X.Y version.
-version = '3.9'
+version = '6.0'
 # The full version, including alpha/beta/rc tags.
-release = '3.9'
+release = '6.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
diff --git a/lib/libcxx/docs/index.rst b/lib/libcxx/docs/index.rst
index b0c8b813f57..3526b47210f 100644
--- a/lib/libcxx/docs/index.rst
+++ b/lib/libcxx/docs/index.rst
@@ -7,7 +7,8 @@
 Overview
 ========
 
-libc++ is a new implementation of the C++ standard library, targeting C++11.
+libc++ is a new implementation of the C++ standard library, targeting C++11 and
+above.
 
 * Features and Goals
 
@@ -119,7 +120,7 @@ This list contains known issues with libc++
 
 A full list of currently open libc++ bugs can be `found here`__.
 
-.. __:  https://llvm.org/bugs/buglist.cgi?component=All%20Bugs&product=libc%2B%2B&query_format=advanced&resolution=---&order=changeddate%20DESC%2Cassigned_to%20DESC%2Cbug_status%2Cpriority%2Cbug_id&list_id=74184
+.. __:  https://bugs.llvm.org/buglist.cgi?component=All%20Bugs&product=libc%2B%2B&query_format=advanced&resolution=---&order=changeddate%20DESC%2Cassigned_to%20DESC%2Cbug_status%2Cpriority%2Cbug_id&list_id=74184
 
 Design Documents
 ----------------
@@ -127,13 +128,15 @@ Design Documents
 .. toctree::
    :maxdepth: 1
 
+   DesignDocs/AvailabilityMarkup
+   DesignDocs/DebugMode
    DesignDocs/CapturingConfigInfo
    DesignDocs/ABIVersioning
-
+   DesignDocs/VisibilityMacros
+   DesignDocs/ThreadingSupportAPI
 
 * `<atomic> design <http://libcxx.llvm.org/atomic_design.html>`_
 * `<type_traits> design <http://libcxx.llvm.org/type_traits_design.html>`_
-* `Status of debug mode <http://libcxx.llvm.org/debug_mode.html>`_
 * `Notes by Marshall Clow`__
 
 .. __: https://cplusplusmusings.wordpress.com/2012/07/05/clang-and-standard-libraries-on-mac-os-x/
@@ -143,7 +146,7 @@ Build Bots and Test Coverage
 
 * `LLVM Buildbot Builders <http://lab.llvm.org:8011/console>`_
 * `Apple Jenkins Builders <http://lab.llvm.org:8080/green/view/Libcxx/>`_
-* `EricWF's Nightly Builders <http://ds2.efcs.ca:8080/console>`_
+* `Windows Appveyor Builders <https://ci.appveyor.com/project/llvm-mirror/libcxx>`_
 * `Code Coverage Results <http://efcs.ca/libcxx-coverage>`_
 
 Getting Involved
@@ -178,7 +181,7 @@ Quick Links
 ===========
 * `LLVM Homepage <http://llvm.org/>`_
 * `libc++abi Homepage <http://libcxxabi.llvm.org/>`_
-* `LLVM Bugzilla <http://llvm.org/bugs/>`_
+* `LLVM Bugzilla <https://bugs.llvm.org/>`_
 * `cfe-commits Mailing List`_
 * `cfe-dev Mailing List`_
 * `Browse libc++ -- SVN <http://llvm.org/svn/llvm-project/libcxx/trunk/>`_