Update libcxx and libcxxabi to LLVM 19.1.4 (#22994)

This updates libcxx and libcxxabi to LLVM 19.1.4:
https://github.com/llvm/llvm-project/releases/tag/llvmorg-19.1.4

The initial update was done using `update_libcxx.py` and
`update_libcxxabi.py`, and subsequent fixes were made in indidual
commits. The commit history here is kind of messy because of CI testing
so not all individual commits are noteworthy.

Additional changes:

- Build libcxx and libcxxabi with C++23:
8b0bfdf

https://github.com/llvm/llvm-project/blob/aadaa00de76ed0c4987b97450dd638f63a385bed/libcxx/src/expected.cpp
was added in llvm/llvm-project#87390 and this
file assumes C++23 to be compiled. Apparently libc++ sources are always
built with C++23 so they don't guard things against it in `src/`:
llvm/llvm-project#87390 (comment)
This commit also builds libc++abi with C++23 because it doesn't seem
there's any downside to it.

- Exclude newly added `compiler_rt_shims.cpp`:
5bbcbf0
We have excluded files in
https://github.com/emscripten-core/emscripten/tree/main/system/lib/libcxx/src/support/win32.
This is a new file added in this directory in
llvm/llvm-project#83575.

- Disable time zone support:
a5f2cbe
We disabled C++20 time zone support in LLVM 18 update (#21638):
df9af64
The list of source files related to time zone support has changed in
llvm/llvm-project#74928, so this commit reflects
it.

- Re-add + update `__assertion_handler` from
`default_assertion_handler.in`:
41f8037
This file was added as a part of LLVM 18 update (#21638) in
8d51927
and mistakenly deleted when I ran `update_libcxx.py`. This file was
copied from
https://github.com/llvm/llvm-project/blob/aadaa00de76ed0c4987b97450dd638f63a385bed/libcxx/vendor/llvm/default_assertion_handler.in,
so this also updates the file with the newest
`default_assertion_handler.in`.

- `_LIBCPP_PSTL_CPU_BACKEND_SERIAL` -> `_LIBCPP_PSTL_BACKEND_SERIAL`:
4b969c3
The name changed in this update, so reflecting it on our
`__config_site`.

- Directly include `pthread.h` from `emscripten/val.h`:
a5a76c3
  Due to file rearrangements happened, this was necessary.

---

Other things to note:

- `std::basic_string<unsigned_char>` is not supported anymore
The support for `std::basic_string<unsigned_char>`, which was being used
by embind, is removed in this version.#23070 removes the uses from
embind.

- libcxxabi uses `__FILE__` in more places
llvm/llvm-project#80689 started to use
`_LIBCXXABI_ASSERT`, which
[uses](https://github.com/llvm/llvm-project/blob/aadaa00de76ed0c4987b97450dd638f63a385bed/libcxxabi/src/abort_message.h#L22)
`__FILE__`, in `private_typeinfo.cpp`.
`__FILE__` macro produces different paths depending on the local
directory names and how the file is given to clang in the command line,
and this file is included in the result of one of our code size tests,
`other.test_minimal_runtime_code_size_hello_embind`, which caused the
result of the test to vary depending on the CI bots and how the library
is built (e.g., whether by embuilder, ninja, or neither).
Even though this was brought to surface during this LLVM 19 update,
`__FILE__` macro could be a problem for producing reproducible builds
anyway. We discussed this problem in #23195, and the fixes landed in
#23222, #23225, and #23256.

Author: aheejin

ChangeLog.md

@@ -20,7 +20,8 @@ See docs/process.md for more on how version tagging works.
 
 3.1.75 (in development)
 -----------------------
-- compiler-rt was updated to LLVM 19.1.4. (#22937)
+- compiler-rt, libcxx, and libcxxabi were updated to LLVM 19.1.4. (#22937 and
+  #22994)
 - The Wasm nontrapping-fptoint feature has been enabled by default. clang will
   generate nontrapping (saturating) float-to-int conversion instructions for
   C typecasts. This should have no effect on programs that do not have

system/include/emscripten/val.h

@@ -18,6 +18,7 @@
 #include <cstdint> // uintptr_t
 #include <vector>
 #include <type_traits>
+#include <pthread.h>
 #if __cplusplus >= 202002L
 #include <coroutine>
 #include <variant>

system/lib/libcxx/include/__algorithm/adjacent_find.h

@@ -26,7 +26,7 @@ _LIBCPP_PUSH_MACROS
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _Iter, class _Sent, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter
+_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter
 __adjacent_find(_Iter __first, _Sent __last, _BinaryPredicate&& __pred) {
   if (__first == __last)
     return __first;
@@ -40,13 +40,13 @@ __adjacent_find(_Iter __first, _Sent __last, _BinaryPredicate&& __pred) {
 }
 
 template <class _ForwardIterator, class _BinaryPredicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
 adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred) {
   return std::__adjacent_find(std::move(__first), std::move(__last), __pred);
 }
 
 template <class _ForwardIterator>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
 adjacent_find(_ForwardIterator __first, _ForwardIterator __last) {
   return std::adjacent_find(std::move(__first), std::move(__last), __equal_to());
 }

system/lib/libcxx/include/__algorithm/all_of.h

@@ -19,7 +19,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIterator, class _Predicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
   for (; __first != __last; ++__first)
     if (!__pred(*__first))

system/lib/libcxx/include/__algorithm/any_of.h

@@ -19,7 +19,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _InputIterator, class _Predicate>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
   for (; __first != __last; ++__first)
     if (__pred(*__first))

system/lib/libcxx/include/__algorithm/binary_search.h

@@ -22,14 +22,14 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 template <class _ForwardIterator, class _Tp, class _Compare>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
   __first = std::lower_bound<_ForwardIterator, _Tp, __comp_ref_type<_Compare> >(__first, __last, __value, __comp);
   return __first != __last && !__comp(__value, *__first);
 }
 
 template <class _ForwardIterator, class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
 binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
   return std::binary_search(__first, __last, __value, __less<>());
 }

system/lib/libcxx/include/__algorithm/clamp.h

@@ -21,7 +21,7 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 #if _LIBCPP_STD_VER >= 17
 template <class _Tp, class _Compare>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI constexpr const _Tp&
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI constexpr const _Tp&
 clamp(_LIBCPP_LIFETIMEBOUND const _Tp& __v,
       _LIBCPP_LIFETIMEBOUND const _Tp& __lo,
       _LIBCPP_LIFETIMEBOUND const _Tp& __hi,
@@ -31,7 +31,7 @@ clamp(_LIBCPP_LIFETIMEBOUND const _Tp& __v,
 }
 
 template <class _Tp>
-_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI constexpr const _Tp&
+[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI constexpr const _Tp&
 clamp(_LIBCPP_LIFETIMEBOUND const _Tp& __v,
       _LIBCPP_LIFETIMEBOUND const _Tp& __lo,
       _LIBCPP_LIFETIMEBOUND const _Tp& __hi) {

system/lib/libcxx/include/__algorithm/comp.h

@@ -10,8 +10,7 @@
 #define _LIBCPP___ALGORITHM_COMP_H
 
 #include <__config>
-#include <__type_traits/integral_constant.h>
-#include <__type_traits/operation_traits.h>
+#include <__type_traits/desugars_to.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
@@ -27,7 +26,7 @@ struct __equal_to {
 };
 
 template <class _Tp, class _Up>
-struct __desugars_to<__equal_tag, __equal_to, _Tp, _Up> : true_type {};
+inline const bool __desugars_to_v<__equal_tag, __equal_to, _Tp, _Up> = true;
 
 // The definition is required because __less is part of the ABI, but it's empty
 // because all comparisons should be transparent.
@@ -42,6 +41,9 @@ struct __less<void, void> {
   }
 };
 
+template <class _Tp>
+inline const bool __desugars_to_v<__less_tag, __less<>, _Tp, _Tp> = true;
+
 _LIBCPP_END_NAMESPACE_STD
 
 #endif // _LIBCPP___ALGORITHM_COMP_H

system/lib/libcxx/include/__algorithm/comp_ref_type.h

@@ -41,9 +41,9 @@ struct __debug_less {
   }
 
   template <class _LHS, class _RHS>
-  _LIBCPP_CONSTEXPR_SINCE_CXX14 inline _LIBCPP_HIDE_FROM_ABI decltype((void)std::declval<_Compare&>()(
-      std::declval<_LHS&>(), std::declval<_RHS&>()))
-  __do_compare_assert(int, _LHS& __l, _RHS& __r) {
+  _LIBCPP_CONSTEXPR_SINCE_CXX14 inline
+      _LIBCPP_HIDE_FROM_ABI decltype((void)std::declval<_Compare&>()(std::declval<_LHS&>(), std::declval<_RHS&>()))
+      __do_compare_assert(int, _LHS& __l, _RHS& __r) {
     _LIBCPP_ASSERT_SEMANTIC_REQUIREMENT(!__comp_(__l, __r), "Comparator does not induce a strict weak ordering");
     (void)__l;
     (void)__r;

system/lib/libcxx/include/__algorithm/copy.h

@@ -32,7 +32,7 @@ template <class, class _InIter, class _Sent, class _OutIter>
 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter> __copy(_InIter, _Sent, _OutIter);
 
 template <class _AlgPolicy>
-struct __copy_loop {
+struct __copy_impl {
   template <class _InIter, class _Sent, class _OutIter>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
   operator()(_InIter __first, _Sent __last, _OutIter __result) const {
@@ -94,9 +94,7 @@ struct __copy_loop {
       __local_first = _Traits::__begin(++__segment_iterator);
     }
   }
-};
 
-struct __copy_trivial {
   // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
   template <class _In, class _Out, __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
@@ -108,7 +106,7 @@ struct __copy_trivial {
 template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
 pair<_InIter, _OutIter> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
 __copy(_InIter __first, _Sent __last, _OutIter __result) {
-  return std::__dispatch_copy_or_move<_AlgPolicy, __copy_loop<_AlgPolicy>, __copy_trivial>(
+  return std::__copy_move_unwrap_iters<__copy_impl<_AlgPolicy> >(
       std::move(__first), std::move(__last), std::move(__result));
 }