[libc++] Fix libc++ in C++03 mode on Clang ToT

[ldionne]

Summary

This is an attempt to fix libc++ in C++03 mode after http://llvm.org/D104500,
which removed implicit move as an extension in C++03.

[ldionne]

Force the use of Clang ToT

[ldionne]

CC => clang-tot instead of clang++-tot

[ldionne]

Fix more instances

[ldionne]

Fix more places

[• Quuxplusone]

FWIW, IMO it's better to just wait for @mizvekov to fix trunk. There is certainly no intention of letting Clang trunk remain in this state for long, and certainly not to ship like this. So if you land D105712, at least please set a reminder to revert it in ~48 hours.

[ldionne]

In D105712#2867593, @Quuxplusone wrote:

FWIW, IMO it's better to just wait for @mizvekov to fix trunk. There is certainly no intention of letting Clang trunk remain in this state for long, and certainly not to ship like this. So if you land D105712, at least please set a reminder to revert it in ~48 hours.

Agreed.

libcxx/include/__hash_table

__hash_table<_Tp, _Hash, _Equal, _Alloc>::__construct_node_hash(
     __node_allocator& __na = __node_alloc();
     __node_holder __h(__node_traits::allocate(__na, 1), _Dp(__na));
     __node_traits::construct(__na, _NodeTypes::__get_ptr(__h->__value_),
                              _VSTD::forward<_First>(__f),
                              _VSTD::forward<_Rest>(__rest)...);
     __h.get_deleter().__value_constructed = true;
     __h->__hash_ = __hash;
     __h->__next_ = nullptr;
+#if defined(_LIBCPP_CXX03_LANG)
+    return _VSTD::move(__h);
+#else
     return __h;
+#endif
 }
 
 template <class _Tp, class _Hash, class _Equal, class _Alloc>
 typename __hash_table<_Tp, _Hash, _Equal, _Alloc>::iterator
 __hash_table<_Tp, _Hash, _Equal, _Alloc>::erase(const_iterator __p)
 {
     __next_pointer __np = __p.__node_;
 #if _LIBCPP_DEBUG_LEVEL == 2

libcxx/utils/ci/run-buildbot

check-generated-output)
     ! grep -q '^--- a' ${BUILD_DIR}/generated_output.patch || false
     # Reject patches that introduce non-ASCII characters or hard tabs.
     # Depends on LC_COLLATE set at the top of this script.
     ! grep -rn '[^ -~]' libcxx/include/ || false
     # Check that no dependency cycles have been introduced.
     python3 libcxx/utils/graph_header_deps.py >/dev/null
 ;;
 generic-cxx03)
-    # TODO: Switch to compiling with Clang ToT once issues with https://reviews.llvm.org/D104500 are resolved.
-    export CC=clang-12
-    export CXX=clang++-12
+    export CC=clang++-tot
+    export CXX=clang++-tot
     clean
     generate-cmake -C "${MONOREPO_ROOT}/libcxx/cmake/caches/Generic-cxx03.cmake" \
                    -DLIBCXX_TEST_CONFIG="${MONOREPO_ROOT}/libcxx/test/configs/libcxx-trunk-shared.cfg.in"
     check-cxx-cxxabi
     check-abi-list
 ;;
 generic-cxx11)
     clean