Import libc++ 8.0.0.

11 files changed, 465 insertions, 77 deletions

diff --git a/lib/libcxx/docs/BuildingLibcxx.rst b/lib/libcxx/docs/BuildingLibcxx.rst
index daf9229a0d0..a498c0027bd 100644
--- a/lib/libcxx/docs/BuildingLibcxx.rst
+++ b/lib/libcxx/docs/BuildingLibcxx.rst
@@ -222,6 +222,15 @@ libc++ specific options
 
   Define libc++ destination prefix.
 
+.. option:: LIBCXX_HERMETIC_STATIC_LIBRARY:BOOL
+
+  **Default**: ``OFF``
+
+  Do not export any symbols from the static libc++ library. This is useful when
+  This is useful when the static libc++ library is being linked into shared
+  libraries that may be used in with other shared libraries that use different
+  C++ library. We want to avoid avoid exporting any libc++ symbols in that case.
+
 .. _libc++experimental options:
 
 libc++experimental Specific Options
@@ -316,6 +325,15 @@ libc++ Feature Options
   Build the libc++ benchmark tests and the Google Benchmark library needed
   to support them.
 
+.. option:: LIBCXX_BENCHMARK_TEST_ARGS:STRING
+
+  **Default**: ``--benchmark_min_time=0.01``
+
+  A semicolon list of arguments to pass when running the libc++ benchmarks using the
+  ``check-cxx-benchmarks`` rule. By default we run the benchmarks for a very short amount of time,
+  since the primary use of ``check-cxx-benchmarks`` is to get test and sanitizer coverage, not to
+  get accurate measurements.
+
 .. option:: LIBCXX_BENCHMARK_NATIVE_STDLIB:STRING
 
   **Default**:: ``""``
@@ -360,6 +378,20 @@ 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_NAMESPACE:STRING
+
+  **Default**: ``__n`` where ``n`` is the current ABI version.
+
+  This option defines the name of the inline ABI versioning namespace. It can be used for building
+  custom versions of libc++ with unique symbol names in order to prevent conflicts or ODR issues
+  with other libc++ versions.
+
+  .. warning::
+    When providing a custom namespace, it's the users responsibility to ensure the name won't cause
+    conflicts with other names defined by libc++, both now and in the future. In particular, inline
+    namespaces of the form ``__[0-9]+`` are strictly reserved by libc++ and may not be used by users.
+    Doing otherwise could cause conflicts and hinder libc++ ABI evolution.
+
 .. option:: LIBCXX_ABI_DEFINES:STRING
 
   **Default**: ``""``
diff --git a/lib/libcxx/docs/DesignDocs/AvailabilityMarkup.rst b/lib/libcxx/docs/DesignDocs/AvailabilityMarkup.rst
index b8b44509790..4e6d80b50bf 100644
--- a/lib/libcxx/docs/DesignDocs/AvailabilityMarkup.rst
+++ b/lib/libcxx/docs/DesignDocs/AvailabilityMarkup.rst
@@ -24,11 +24,11 @@ systems. For example::
 
     // Define availability macros.
     #if defined(_LIBCPP_USE_AVAILABILITY_APPLE)
-    #define _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS __attribute__((unavailable))
+    # 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
+    # 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.
@@ -43,9 +43,9 @@ For example::
 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 {
+    _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:
 
@@ -55,7 +55,7 @@ or on a particular symbol:
 Testing
 =======
 
-Some parameters can be passed to lit to run the test-suite and exercising the
+Some parameters can be passed to lit to run the test-suite and exercise the
 availability.
 
 * The `platform` parameter controls the deployment target. For example lit can
@@ -65,14 +65,11 @@ availability.
   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:
+* if `--param=platform=macosx10.8` is passed, the following features will be available:
 
   - availability
   - availability=x86_64
@@ -81,11 +78,11 @@ Tests can be marked as XFAIL based on multiple features made available by lit:
   - 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
+  This feature is used to XFAIL a test that *is* using a class or 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:
+* if `use_system_cxx_lib` and `--param=platform=macosx10.8` are passed to lit,
+  the following features will also be available:
 
   - with_system_cxx_lib
   - with_system_cxx_lib=x86_64
@@ -94,21 +91,9 @@ Tests can be marked as XFAIL based on multiple features made available by lit:
   - 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
+  This feature is used to XFAIL a test that is *not* using a class or 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.
+  system. For example, if the test exhibits a bug in the libc on a particular
+  system version, or if the test uses a symbol that is not available on an
+  older version of the dylib (but for which there is no availability markup,
+  otherwise the XFAIL should use `availability` above).
diff --git a/lib/libcxx/docs/DesignDocs/CapturingConfigInfo.rst b/lib/libcxx/docs/DesignDocs/CapturingConfigInfo.rst
index 88102251d93..29156bff8bc 100644
--- a/lib/libcxx/docs/DesignDocs/CapturingConfigInfo.rst
+++ b/lib/libcxx/docs/DesignDocs/CapturingConfigInfo.rst
@@ -28,7 +28,7 @@ Design Goals
   It makes developers lives harder if they have to regenerate the libc++ headers
   every time they are modified.
 
-* The solution should not make any of the libc++ headers dependant on
+* The solution should not make any of the libc++ headers dependent on
   files generated by the build system. The headers should be able to compile
   out of the box without any modification.
 
diff --git a/lib/libcxx/docs/DesignDocs/FeatureTestMacros.rst b/lib/libcxx/docs/DesignDocs/FeatureTestMacros.rst
new file mode 100644
index 00000000000..d55af96c674
--- /dev/null
+++ b/lib/libcxx/docs/DesignDocs/FeatureTestMacros.rst
@@ -0,0 +1,44 @@
+===================
+Feature Test Macros
+===================
+
+.. contents::
+   :local:
+
+Overview
+========
+
+Libc++ implements the C++ feature test macros as specified in the C++2a standard,
+and before that in non-normative guiding documents (`See cppreference <https://en.cppreference.com/w/User:D41D8CD98F/feature_testing_macros>`)
+
+Design
+======
+
+Feature test macros are tricky to track, implement, test, and document correctly.
+They must be available from a list of headers, they may have different values in
+different dialects, and they may or may not be implemented by libc++. In order to
+track all of these conditions correctly and easily, we want a Single Source of
+Truth (SSoT) that defines each feature test macro, its values, the headers it
+lives in, and whether or not is is implemented by libc++. From this SSoA we
+have enough information to automatically generate the `<version>` header,
+the tests, and the documentation.
+
+Therefore we maintain a SSoA in
+`libcxx/test/std/language.support/support.limits/support.limits.general/generate_feature_test_macro_components.py`
+which doubles as a script to generate the following components:
+
+* The `<version>` header.
+* The version tests under `support.limits.general`.
+* Documentation of libc++'s implementation of each macro.
+
+Usage
+=====
+
+The `generate_feature_test_macro_components.py` script is used to track and
+update feature test macros in libc++.
+
+Whenever a feature test macro is added or changed, the table should be updated
+and the script should be re-ran. The script will clobber the existing test files
+and the documentation and it will generate a new `<version>` header as a
+temporary file. The generated `<version>` header should be merged with the
+existing one.
\ No newline at end of file
diff --git a/lib/libcxx/docs/DesignDocs/VisibilityMacros.rst b/lib/libcxx/docs/DesignDocs/VisibilityMacros.rst
index ab577df1364..d0d4f0adb22 100644
--- a/lib/libcxx/docs/DesignDocs/VisibilityMacros.rst
+++ b/lib/libcxx/docs/DesignDocs/VisibilityMacros.rst
@@ -22,11 +22,11 @@ Visibility Macros
   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**
+**_LIBCPP_EXPORTED_FROM_ABI**
   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.
+  only be applied to objects defined in the libc++ runtime library. On Windows,
+  this macro applies `dllimport`/`dllexport` to the symbol, and on other
+  platforms it gives the symbol default visibility.
 
 **_LIBCPP_OVERRIDABLE_FUNC_VIS**
   Mark a symbol as being exported by the libc++ library, but allow it to be
@@ -44,6 +44,21 @@ Visibility Macros
   Mark a function as not being part of the ABI of any final linked image that
   uses it.
 
+**_LIBCPP_HIDE_FROM_ABI_AFTER_V1**
+  Mark a function as being hidden from the ABI (per `_LIBCPP_HIDE_FROM_ABI`)
+  when libc++ is built with an ABI version after ABI v1. This macro is used to
+  maintain ABI compatibility for symbols that have been historically exported
+  by libc++ in v1 of the ABI, but that we don't want to export in the future.
+
+  This macro works as follows. When we build libc++, we either hide the symbol
+  from the ABI (if the symbol is not part of the ABI in the version we're
+  building), or we leave it included. From user code (i.e. when we're not
+  building libc++), the macro always marks symbols as internal so that programs
+  built using new libc++ headers stop relying on symbols that are removed from
+  the ABI in a future version. Each time we release a new stable version of the
+  ABI, we should create a new _LIBCPP_HIDE_FROM_ABI_AFTER_XXX macro, and we can
+  use it to start removing symbols from the ABI after that stable version.
+
 **_LIBCPP_HIDE_FROM_ABI_PER_TU**
   This macro controls whether symbols hidden from the ABI with `_LIBCPP_HIDE_FROM_ABI`
   are local to each translation unit in addition to being local to each final
@@ -67,9 +82,9 @@ Visibility Macros
 **_LIBCPP_HIDE_FROM_ABI_PER_TU_BY_DEFAULT**
   This macro controls the default value for `_LIBCPP_HIDE_FROM_ABI_PER_TU`.
   When the macro is defined, per TU ABI insulation is enabled by default, and
-  `_LIBCPP_HIDE_FROM_ABI_PER_TU` is defined to 1 unless overriden by users.
+  `_LIBCPP_HIDE_FROM_ABI_PER_TU` is defined to 1 unless overridden by users.
   Otherwise, per TU ABI insulation is disabled by default, and
-  `_LIBCPP_HIDE_FROM_ABI_PER_TU` is defined to 0 unless overriden by users.
+  `_LIBCPP_HIDE_FROM_ABI_PER_TU` is defined to 0 unless overridden by users.
 
   This macro is intended for vendors to control whether they want to ship
   libc++ with per TU ABI insulation enabled by default. Users can always
@@ -77,7 +92,7 @@ Visibility Macros
   appropriately.
 
   By default, this macro is not defined, which means that per TU ABI insulation
-  is not provided unless explicitly overriden by users.
+  is not provided unless explicitly overridden by users.
 
 **_LIBCPP_TYPE_VIS**
   Mark a type's typeinfo, vtable and members as having default visibility.
@@ -172,15 +187,6 @@ Visibility Macros
   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*.
diff --git a/lib/libcxx/docs/FeatureTestMacroTable.rst b/lib/libcxx/docs/FeatureTestMacroTable.rst
new file mode 100644
index 00000000000..d900497eba7
--- /dev/null
+++ b/lib/libcxx/docs/FeatureTestMacroTable.rst
@@ -0,0 +1,200 @@
+.. _FeatureTestMacroTable:
+
+==========================
+Feature Test Macro Support
+==========================
+
+.. contents::
+   :local:
+
+Overview
+========
+
+This file documents the feature test macros currently supported by libc++.
+
+.. _feature-status:
+
+Status
+======
+
+.. table:: Current Status
+     :name: feature-status-table
+     :widths: auto
+     
+    ================================================= =================
+    Macro Name                                        Value            
+    ================================================= =================
+    **C++ 14**                                                         
+    -------------------------------------------------------------------
+    ``__cpp_lib_chrono_udls``                         ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_complex_udls``                        ``201309L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_exchange_function``                   ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_generic_associative_lookup``          ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_integer_sequence``                    ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_integral_constant_callable``          ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_is_final``                            ``201402L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_is_null_pointer``                     ``201309L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_make_reverse_iterator``               ``201402L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_make_unique``                         ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_null_iterators``                      ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_quoted_string_io``                    ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_result_of_sfinae``                    ``201210L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_robust_nonmodifying_seq_ops``         ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_shared_timed_mutex``                  ``201402L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_string_udls``                         ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_transformation_trait_aliases``        ``201304L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_transparent_operators``               ``201210L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_tuple_element_t``                     ``201402L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_tuples_by_type``                      ``201304L``      
+    ------------------------------------------------- -----------------
+    **C++ 17**                                                         
+    -------------------------------------------------------------------
+    ``__cpp_lib_addressof_constexpr``                 ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_allocator_traits_is_always_equal``    ``201411L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_any``                                 ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_apply``                               ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_array_constexpr``                     ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_as_const``                            ``201510L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_atomic_is_always_lock_free``          ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_bool_constant``                       ``201505L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_boyer_moore_searcher``                *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_byte``                                ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_chrono``                              ``201611L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_clamp``                               ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_enable_shared_from_this``             ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_execution``                           *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_filesystem``                          ``201703L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_gcd_lcm``                             ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_hardware_interference_size``          ``201703L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_has_unique_object_representations``   ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_hypot``                               ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_incomplete_container_elements``       ``201505L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_invoke``                              ``201411L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_is_aggregate``                        ``201703L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_is_invocable``                        ``201703L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_is_swappable``                        ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_launder``                             ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_logical_traits``                      ``201510L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_make_from_tuple``                     ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_map_try_emplace``                     ``201411L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_math_special_functions``              *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_memory_resource``                     *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_node_extract``                        ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_nonmember_container_access``          ``201411L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_not_fn``                              ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_optional``                            ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_parallel_algorithm``                  *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_raw_memory_algorithms``               ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_sample``                              ``201603L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_scoped_lock``                         ``201703L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_shared_mutex``                        ``201505L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_shared_ptr_arrays``                   *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_shared_ptr_weak_type``                ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_string_view``                         ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_to_chars``                            *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_transparent_operators``               ``201510L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_type_trait_variable_templates``       ``201510L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_uncaught_exceptions``                 ``201411L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_unordered_map_try_emplace``           ``201411L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_variant``                             ``201606L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_void_t``                              ``201411L``      
+    ------------------------------------------------- -----------------
+    **C++ 2a**                                                         
+    -------------------------------------------------------------------
+    ``__cpp_lib_atomic_ref``                          *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_bind_front``                          *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_bit_cast``                            *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_char8_t``                             ``201811L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_concepts``                            *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_constexpr_misc``                      *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_constexpr_swap_algorithms``           *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_destroying_delete``                   *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_erase_if``                            ``201811L``      
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_generic_unordered_lookup``            *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_is_constant_evaluated``               *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_list_remove_return_type``             *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_ranges``                              *unimplemented*  
+    ------------------------------------------------- -----------------
+    ``__cpp_lib_three_way_comparison``                *unimplemented*  
+    ================================================= =================
+
+
diff --git a/lib/libcxx/docs/ReleaseNotes.rst b/lib/libcxx/docs/ReleaseNotes.rst
new file mode 100644
index 00000000000..ca5a534ae84
--- /dev/null
+++ b/lib/libcxx/docs/ReleaseNotes.rst
@@ -0,0 +1,48 @@
+==========================
+Libc++ 8.0.0 Release Notes
+==========================
+
+.. contents::
+   :local:
+   :depth: 2
+
+Written by the `Libc++ Team <https://libcxx.llvm.org>`_
+
+Introduction
+============
+
+This document contains the release notes for the libc++ C++ Standard Library,
+part of the LLVM Compiler Infrastructure, release 8.0.0. Here we describe the
+status of libc++ in some detail, including major improvements from the previous
+release and new feature work. For the general LLVM release notes, see `the LLVM
+documentation <https://llvm.org/docs/ReleaseNotes.html>`_. All LLVM releases may
+be downloaded from the `LLVM releases web site <https://releases.llvm.org/>`_.
+
+For more information about libc++, please see the `Libc++ Web Site
+<https://libcxx.llvm.org>`_ or the `LLVM Web Site <https://llvm.org>`_.
+
+What's New in Libc++ 8.0.0?
+===========================
+
+API Changes
+-----------
+- Building libc++ for Mac OSX 10.6 is not supported anymore.
+- Starting with LLVM 8.0.0, users that wish to link together translation units
+  built with different versions of libc++'s headers into the same final linked
+  image MUST define the _LIBCPP_HIDE_FROM_ABI_PER_TU macro to 1 when building
+  those translation units. Not defining _LIBCPP_HIDE_FROM_ABI_PER_TU to 1 and
+  linking translation units built with different versions of libc++'s headers
+  together may lead to ODR violations and ABI issues. On the flipside, code
+  size improvements should be expected for everyone not defining the macro.
+- Starting with LLVM 8.0.0, std::dynarray has been removed from the library.
+  std::dynarray was a feature proposed for C++14 that was pulled from the
+  Standard at the last minute and was never standardized. Since there are no
+  plans to standardize this facility it is being removed.
+- Starting with LLVM 8.0.0, std::bad_array_length has been removed from the
+  library. std::bad_array_length was a feature proposed for C++14 alongside
+  std::dynarray, but it never actually made it into the C++ Standard. There
+  are no plans to standardize this feature at this time. Formally speaking,
+  this removal constitutes an ABI break because the symbols were shipped in
+  the shared library. However, on macOS systems, the feature was not usable
+  because it was hidden behind availability annotations. We do not expect
+  any actual breakage to happen from this change.
diff --git a/lib/libcxx/docs/TestingLibcxx.rst b/lib/libcxx/docs/TestingLibcxx.rst
index 43c0684dc7d..ebbbf628ac0 100644
--- a/lib/libcxx/docs/TestingLibcxx.rst
+++ b/lib/libcxx/docs/TestingLibcxx.rst
@@ -138,8 +138,7 @@ configuration. Passing the option on the command line will override the default.
   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_cxx_lib is provided.
+  for this option is `cxx_library_root`.
 
 .. option:: use_system_cxx_lib=<bool>
 
@@ -155,14 +154,6 @@ configuration. Passing the option on the command line will override the default.
   the default value. Otherwise the default value is True on Windows and False
   on every other platform.
 
-.. option:: no_default_flags=<bool>
-
-  **Default**: False
-
-  Disable all default compile and link flags from being added. When this
-  option is used only flags specified using the compile_flags and link_flags
-  will be used.
-
 .. option:: compile_flags="<list-of-args>"
 
   Specify additional compile flags as a space delimited string.
diff --git a/lib/libcxx/docs/UsingLibcxx.rst b/lib/libcxx/docs/UsingLibcxx.rst
index e10a27c598a..899656cca1d 100644
--- a/lib/libcxx/docs/UsingLibcxx.rst
+++ b/lib/libcxx/docs/UsingLibcxx.rst
@@ -203,8 +203,10 @@ thread safety annotations.
   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.
+    * Giving `set`, `map`, `multiset`, `multimap` and their `unordered_`
+      counterparts a comparator which is not const callable.
+    * Giving an unordered associative container a hasher that is not const
+      callable.
 
 **_LIBCPP_NO_VCRUNTIME**:
   Microsoft's C and C++ headers are fairly entangled, and some of their C++
@@ -226,6 +228,26 @@ thread safety annotations.
   replacement scenarios from working, e.g. replacing `operator new` and
   expecting a non-replaced `operator new[]` to call the replaced `operator new`.
 
+**_LIBCPP_ENABLE_NODISCARD**:
+  Allow the library to add ``[[nodiscard]]`` attributes to entities not specified
+  as ``[[nodiscard]]`` by the current language dialect. This includes
+  backporting applications of ``[[nodiscard]]`` from newer dialects and
+  additional extended applications at the discretion of the library. All
+  additional applications of ``[[nodiscard]]`` are disabled by default.
+  See :ref:`Extended Applications of [[nodiscard]] <nodiscard extension>` for
+  more information.
+
+**_LIBCPP_DISABLE_NODISCARD_EXT**:
+  This macro prevents the library from applying ``[[nodiscard]]`` to entities
+  purely as an extension. See :ref:`Extended Applications of [[nodiscard]] <nodiscard extension>`
+  for more information.
+
+**_LIBCPP_ENABLE_DEPRECATION_WARNINGS**:
+  This macro enables warnings when using deprecated components. For example,
+  when compiling in C++11 mode, using `std::auto_ptr` with the macro defined
+  will trigger a warning saying that `std::auto_ptr` is deprecated. By default,
+  this macro is not defined.
+
 C++17 Specific Configuration Macros
 -----------------------------------
 **_LIBCPP_ENABLE_CXX17_REMOVED_FEATURES**:
@@ -238,3 +260,58 @@ C++17 Specific Configuration Macros
 
 **_LIBCPP_ENABLE_CXX17_REMOVED_AUTO_PTR**:
   This macro is used to re-enable `std::auto_ptr` in C++17.
+
+C++2a Specific Configuration Macros:
+------------------------------------
+**_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17**:
+  This macro can be used to disable diagnostics emitted from functions marked
+  ``[[nodiscard]]`` in dialects after C++17.  See :ref:`Extended Applications of [[nodiscard]] <nodiscard extension>`
+  for more information.
+
+
+Libc++ Extensions
+=================
+
+This section documents various extensions provided by libc++, how they're
+provided, and any information regarding how to use them.
+
+.. _nodiscard extension:
+
+Extended applications of ``[[nodiscard]]``
+------------------------------------------
+
+The ``[[nodiscard]]`` attribute is intended to help users find bugs where
+function return values are ignored when they shouldn't be. After C++17 the
+C++ standard has started to declared such library functions as ``[[nodiscard]]``.
+However, this application is limited and applies only to dialects after C++17.
+Users who want help diagnosing misuses of STL functions may desire a more
+liberal application of ``[[nodiscard]]``.
+
+For this reason libc++ provides an extension that does just that! The
+extension must be enabled by defining ``_LIBCPP_ENABLE_NODISCARD``. The extended
+applications of ``[[nodiscard]]`` takes two forms:
+
+1. Backporting ``[[nodiscard]]`` to entities declared as such by the
+   standard in newer dialects, but not in the present one.
+
+2. Extended applications of ``[[nodiscard]]``, at the libraries discretion,
+   applied to entities never declared as such by the standard.
+
+Users may also opt-out of additional applications ``[[nodiscard]]`` using
+additional macros.
+
+Applications of the first form, which backport ``[[nodiscard]]`` from a newer
+dialect may be disabled using macros specific to the dialect it was added. For
+example ``_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17``.
+
+Applications of the second form, which are pure extensions, may be disabled
+by defining ``_LIBCPP_DISABLE_NODISCARD_EXT``.
+
+
+Entities declared with ``_LIBCPP_NODISCARD_EXT``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This section lists all extended applications of ``[[nodiscard]]`` to entities
+which no dialect declares as such (See the second form described above).
+
+* ``get_temporary_buffer``
diff --git a/lib/libcxx/docs/conf.py b/lib/libcxx/docs/conf.py
index 4c1ea3653cd..50b372cf84e 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'2011-2017, LLVM Project'
+copyright = u'2011-2018, 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 = '7.0'
+version = '8.0'
 # The full version, including alpha/beta/rc tags.
-release = '7.0'
+release = '8.0'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -241,7 +241,7 @@ texinfo_documents = [
 #texinfo_show_urls = 'footnote'
 
 
-# FIXME: Define intersphinx configration.
+# FIXME: Define intersphinx configuration.
 intersphinx_mapping = {}
 
 
diff --git a/lib/libcxx/docs/index.rst b/lib/libcxx/docs/index.rst
index e4b3a879da9..fddf74b66a9 100644
--- a/lib/libcxx/docs/index.rst
+++ b/lib/libcxx/docs/index.rst
@@ -34,11 +34,17 @@ Getting Started with libc++
 .. toctree::
    :maxdepth: 2
 
+   ReleaseNotes
    UsingLibcxx
    BuildingLibcxx
    TestingLibcxx
 
 
+.. toctree::
+    :hidden:
+
+    FeatureTestMacroTable
+
 Current Status
 --------------
 
@@ -79,8 +85,8 @@ reasons, but some of the major ones are:
 Platform and Compiler Support
 -----------------------------
 
-libc++ is known to work on the following platforms, using gcc-4.2 and
-clang  (lack of C++11 language support disables some functionality).
+libc++ is known to work on the following platforms, using gcc and
+clang.
 Note that functionality provided by ``<atomic>`` is only functional with clang
 and GCC.
 
@@ -104,8 +110,9 @@ C++ Dialect Support
 
 * C++11 - Complete
 * `C++14 - Complete <http://libcxx.llvm.org/cxx1y_status.html>`__
-* `C++1z - In Progress <http://libcxx.llvm.org/cxx1z_status.html>`__
+* `C++17 - In Progress <http://libcxx.llvm.org/cxx1z_status.html>`__
 * `Post C++14 Technical Specifications - In Progress <http://libcxx.llvm.org/ts1z_status.html>`__
+* :ref:`C++ Feature Test Macro Status <feature-status>`
 
 Notes and Known Issues
 ----------------------
@@ -135,6 +142,7 @@ Design Documents
    DesignDocs/VisibilityMacros
    DesignDocs/ThreadingSupportAPI
    DesignDocs/FileTimeType
+   DesignDocs/FeatureTestMacros
 
 * `<atomic> design <http://libcxx.llvm.org/atomic_design.html>`_
 * `<type_traits> design <http://libcxx.llvm.org/type_traits_design.html>`_
@@ -160,21 +168,18 @@ and `Getting started with LLVM <http://llvm.org/docs/GettingStarted.html>`__.
 
 If you think you've found a bug in libc++, please report it using
 the `LLVM Bugzilla`_. If you're not sure, you
-can post a message to the `cfe-dev mailing list`_ or on IRC.
-Please include "libc++" in your subject.
+can post a message to the `libcxx-dev mailing list`_ or on IRC.
 
 **Patches**
 
 If you want to contribute a patch to libc++, the best place for that is
-`Phabricator <http://llvm.org/docs/Phabricator.html>`_. Please include [libcxx] in the subject and
-add `cfe-commits` as a subscriber. Also make sure you are subscribed to the
-`cfe-commits mailing list <http://lists.llvm.org/mailman/listinfo/cfe-commits>`_.
+`Phabricator <http://llvm.org/docs/Phabricator.html>`_. Please add `libcxx-commits` as a subscriber.
+Also make sure you are subscribed to the `libcxx-commits mailing list <http://lists.llvm.org/mailman/listinfo/libcxx-commits>`_.
 
 **Discussion and Questions**
 
 Send discussions and questions to the
-`cfe-dev mailing list <http://lists.llvm.org/mailman/listinfo/cfe-dev>`_.
-Please include [libcxx] in the subject.
+`libcxx-dev mailing list <http://lists.llvm.org/mailman/listinfo/libcxx-dev>`_.
 
 
 
@@ -183,7 +188,7 @@ Quick Links
 * `LLVM Homepage <http://llvm.org/>`_
 * `libc++abi Homepage <http://libcxxabi.llvm.org/>`_
 * `LLVM Bugzilla <https://bugs.llvm.org/>`_
-* `cfe-commits Mailing List`_
-* `cfe-dev Mailing List`_
+* `libcxx-commits Mailing List`_
+* `libcxx-dev Mailing List`_
 * `Browse libc++ -- SVN <http://llvm.org/svn/llvm-project/libcxx/trunk/>`_
 * `Browse libc++ -- ViewVC <http://llvm.org/viewvc/llvm-project/libcxx/trunk/>`_