diff --git a/lib/libcxxabi/include/__cxxabi_config.h b/lib/libcxxabi/include/__cxxabi_config.h
index e8aa37e6d5..759445dac9 100644
--- a/lib/libcxxabi/include/__cxxabi_config.h
+++ b/lib/libcxxabi/include/__cxxabi_config.h
@@ -103,4 +103,10 @@
 #define _LIBCXXABI_DTOR_FUNC
 #endif
 
+#if __cplusplus < 201103L
+#  define _LIBCXXABI_NOEXCEPT throw()
+#else
+#  define _LIBCXXABI_NOEXCEPT noexcept
+#endif
+
 #endif // ____CXXABI_CONFIG_H
diff --git a/lib/libcxxabi/include/cxxabi.h b/lib/libcxxabi/include/cxxabi.h
index 8d1b5c9b55..9ea93680f6 100644
--- a/lib/libcxxabi/include/cxxabi.h
+++ b/lib/libcxxabi/include/cxxabi.h
@@ -43,16 +43,16 @@ extern "C"  {
 
 // 2.4.2 Allocating the Exception Object
 extern _LIBCXXABI_FUNC_VIS void *
-__cxa_allocate_exception(size_t thrown_size) throw();
+__cxa_allocate_exception(size_t thrown_size) _LIBCXXABI_NOEXCEPT;
 extern _LIBCXXABI_FUNC_VIS void
-__cxa_free_exception(void *thrown_exception) throw();
+__cxa_free_exception(void *thrown_exception) _LIBCXXABI_NOEXCEPT;
 // This function is an LLVM extension, which mirrors the same extension in libsupc++ and libcxxrt
 extern _LIBCXXABI_FUNC_VIS __cxa_exception*
 #ifdef __wasm__
 // In Wasm, a destructor returns its argument
-__cxa_init_primary_exception(void* object, std::type_info* tinfo, void*(_LIBCXXABI_DTOR_FUNC* dest)(void*)) throw();
+__cxa_init_primary_exception(void* object, std::type_info* tinfo, void*(_LIBCXXABI_DTOR_FUNC* dest)(void*)) _LIBCXXABI_NOEXCEPT;
 #else
-__cxa_init_primary_exception(void* object, std::type_info* tinfo, void(_LIBCXXABI_DTOR_FUNC* dest)(void*)) throw();
+__cxa_init_primary_exception(void* object, std::type_info* tinfo, void(_LIBCXXABI_DTOR_FUNC* dest)(void*)) _LIBCXXABI_NOEXCEPT;
 #endif
 
 // 2.4.3 Throwing the Exception Object
@@ -66,13 +66,13 @@ __cxa_throw(void *thrown_exception, std::type_info *tinfo,
 
 // 2.5.3 Exception Handlers
 extern _LIBCXXABI_FUNC_VIS void *
-__cxa_get_exception_ptr(void *exceptionObject) throw();
+__cxa_get_exception_ptr(void *exceptionObject) _LIBCXXABI_NOEXCEPT;
 extern _LIBCXXABI_FUNC_VIS void *
-__cxa_begin_catch(void *exceptionObject) throw();
+__cxa_begin_catch(void *exceptionObject) _LIBCXXABI_NOEXCEPT;
 extern _LIBCXXABI_FUNC_VIS void __cxa_end_catch();
 #if defined(_LIBCXXABI_ARM_EHABI)
 extern _LIBCXXABI_FUNC_VIS bool
-__cxa_begin_cleanup(void *exceptionObject) throw();
+__cxa_begin_cleanup(void *exceptionObject) _LIBCXXABI_NOEXCEPT;
 extern _LIBCXXABI_FUNC_VIS void __cxa_end_cleanup();
 #endif
 extern _LIBCXXABI_FUNC_VIS std::type_info *__cxa_current_exception_type();
@@ -80,7 +80,7 @@ extern _LIBCXXABI_FUNC_VIS std::type_info *__cxa_current_exception_type();
 // GNU extension
 // Calls `terminate` with the current exception being caught. This function is used by GCC when a `noexcept` function
 // throws an exception inside a try/catch block and doesn't catch it.
-extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void __cxa_call_terminate(void*) throw();
+extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void __cxa_call_terminate(void*) _LIBCXXABI_NOEXCEPT;
 
 // 2.5.4 Rethrowing Exceptions
 extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void __cxa_rethrow();
@@ -168,23 +168,23 @@ extern _LIBCXXABI_FUNC_VIS char *__cxa_demangle(const char *mangled_name,
 
 // Apple additions to support C++ 0x exception_ptr class
 // These are primitives to wrap a smart pointer around an exception object
-extern _LIBCXXABI_FUNC_VIS void *__cxa_current_primary_exception() throw();
+extern _LIBCXXABI_FUNC_VIS void *__cxa_current_primary_exception() _LIBCXXABI_NOEXCEPT;
 extern _LIBCXXABI_FUNC_VIS void
 __cxa_rethrow_primary_exception(void *primary_exception);
 extern _LIBCXXABI_FUNC_VIS void
-__cxa_increment_exception_refcount(void *primary_exception) throw();
+__cxa_increment_exception_refcount(void *primary_exception) _LIBCXXABI_NOEXCEPT;
 extern _LIBCXXABI_FUNC_VIS void
-__cxa_decrement_exception_refcount(void *primary_exception) throw();
+__cxa_decrement_exception_refcount(void *primary_exception) _LIBCXXABI_NOEXCEPT;
 
 // Apple extension to support std::uncaught_exception()
-extern _LIBCXXABI_FUNC_VIS bool __cxa_uncaught_exception() throw();
-extern _LIBCXXABI_FUNC_VIS unsigned int __cxa_uncaught_exceptions() throw();
+extern _LIBCXXABI_FUNC_VIS bool __cxa_uncaught_exception() _LIBCXXABI_NOEXCEPT;
+extern _LIBCXXABI_FUNC_VIS unsigned int __cxa_uncaught_exceptions() _LIBCXXABI_NOEXCEPT;
 
 #if defined(__linux__) || defined(__Fuchsia__)
 // Linux and Fuchsia TLS support. Not yet an official part of the Itanium ABI.
 // https://sourceware.org/glibc/wiki/Destructor%20support%20for%20thread_local%20variables
 extern _LIBCXXABI_FUNC_VIS int __cxa_thread_atexit(void (*)(void *), void *,
-                                                   void *) throw();
+                                                   void *) _LIBCXXABI_NOEXCEPT;
 #endif
 
 } // extern "C"
diff --git a/lib/libcxxabi/src/abort_message.cpp b/lib/libcxxabi/src/abort_message.cpp
index 859a5031b9..d51d9d87d3 100644
--- a/lib/libcxxabi/src/abort_message.cpp
+++ b/lib/libcxxabi/src/abort_message.cpp
@@ -12,13 +12,8 @@
 #include "abort_message.h"
 
 #ifdef __BIONIC__
-#   include <android/api-level.h>
-#   if __ANDROID_API__ >= 21
-#       include <syslog.h>
-        extern "C" void android_set_abort_message(const char* msg);
-#   else
-#       include <assert.h>
-#   endif // __ANDROID_API__ >= 21
+#  include <syslog.h>
+extern "C" void android_set_abort_message(const char* msg);
 #endif // __BIONIC__
 
 #if defined(__APPLE__) && __has_include(<CrashReporterClient.h>)
@@ -26,7 +21,7 @@
 #   define _LIBCXXABI_USE_CRASHREPORTER_CLIENT
 #endif
 
-void abort_message(const char* format, ...)
+void __abort_message(const char* format, ...)
 {
     // Write message to stderr. We do this before formatting into a
     // variable-size buffer so that we still get some information if
@@ -59,7 +54,6 @@ void abort_message(const char* format, ...)
     vasprintf(&buffer, format, list);
     va_end(list);
 
-#   if __ANDROID_API__ >= 21
     // Show error in tombstone.
     android_set_abort_message(buffer);
 
@@ -67,12 +61,6 @@ void abort_message(const char* format, ...)
     openlog("libc++abi", 0, 0);
     syslog(LOG_CRIT, "%s", buffer);
     closelog();
-#   else
-    // The good error reporting wasn't available in Android until L. Since we're
-    // about to abort anyway, just call __assert2, which will log _somewhere_
-    // (tombstone and/or logcat) in older releases.
-    __assert2(__FILE__, __LINE__, __func__, buffer);
-#   endif // __ANDROID_API__ >= 21
 #endif // __BIONIC__
 
     abort();
diff --git a/lib/libcxxabi/src/abort_message.h b/lib/libcxxabi/src/abort_message.h
index 2cd09db1fb..85d6ba36e2 100644
--- a/lib/libcxxabi/src/abort_message.h
+++ b/lib/libcxxabi/src/abort_message.h
@@ -12,7 +12,7 @@
 #include "cxxabi.h"
 
 extern "C" _LIBCXXABI_HIDDEN _LIBCXXABI_NORETURN void
-abort_message(const char *format, ...) __attribute__((format(printf, 1, 2)));
+__abort_message(const char *format, ...) __attribute__((format(printf, 1, 2)));
 
 #ifndef _LIBCXXABI_ASSERT
 // zig patch: respect NDEBUG. Otherwise the file path makes it into the binary,
@@ -24,7 +24,7 @@ abort_message(const char *format, ...) __attribute__((format(printf, 1, 2)));
     do {                                                                                                               \
       if (!(expr)) {                                                                                                   \
         char const* __msg = (msg);                                                                                     \
-        ::abort_message("%s:%d: %s", __FILE__, __LINE__, __msg);                                                       \
+        ::__abort_message("%s:%d: %s", __FILE__, __LINE__, __msg);                                                     \
       }                                                                                                                \
     } while (false)
 
diff --git a/lib/libcxxabi/src/cxa_default_handlers.cpp b/lib/libcxxabi/src/cxa_default_handlers.cpp
index 7bcfca069f..b029982ea8 100644
--- a/lib/libcxxabi/src/cxa_default_handlers.cpp
+++ b/lib/libcxxabi/src/cxa_default_handlers.cpp
@@ -10,8 +10,7 @@
 //===----------------------------------------------------------------------===//
 
 #include <exception>
-#include <memory>
-#include <stdlib.h>
+#include <new>
 #include "abort_message.h"
 #include "cxxabi.h"
 #include "cxa_handlers.h"
@@ -23,17 +22,7 @@
 
 static constinit const char* cause = "uncaught";
 
-#ifndef _LIBCXXABI_NO_EXCEPTIONS
-// Demangle the given string, or return the string as-is in case of an error.
-static std::unique_ptr<char const, void (*)(char const*)> demangle(char const* str)
-{
-#if !defined(LIBCXXABI_NON_DEMANGLING_TERMINATE)
-    if (const char* result = __cxxabiv1::__cxa_demangle(str, nullptr, nullptr, nullptr))
-        return {result, [](char const* p) { std::free(const_cast<char*>(p)); }};
-#endif
-    return {str, [](char const*) { /* nothing to free */ }};
-}
-
+#  ifndef _LIBCXXABI_NO_EXCEPTIONS
 __attribute__((noreturn))
 static void demangling_terminate_handler()
 {
@@ -42,18 +31,18 @@ static void demangling_terminate_handler()
 
     // If there is no uncaught exception, just note that we're terminating
     if (!globals)
-        abort_message("terminating");
+        __abort_message("terminating");
 
     __cxa_exception* exception_header = globals->caughtExceptions;
     if (!exception_header)
-        abort_message("terminating");
+        __abort_message("terminating");
 
     _Unwind_Exception* unwind_exception =
         reinterpret_cast<_Unwind_Exception*>(exception_header + 1) - 1;
 
     // If we're terminating due to a foreign exception
     if (!__isOurExceptionClass(unwind_exception))
-        abort_message("terminating due to %s foreign exception", cause);
+        __abort_message("terminating due to %s foreign exception", cause);
 
     void* thrown_object =
         __getExceptionClass(unwind_exception) == kOurDependentExceptionClass ?
@@ -61,7 +50,17 @@ static void demangling_terminate_handler()
             exception_header + 1;
     const __shim_type_info* thrown_type =
         static_cast<const __shim_type_info*>(exception_header->exceptionType);
-    auto name = demangle(thrown_type->name());
+
+    auto name = [str = thrown_type->name()] {
+#    ifndef LIBCXXABI_NON_DEMANGLING_TERMINATE
+      if (const char* result = __cxxabiv1::__cxa_demangle(str, nullptr, nullptr, nullptr))
+        // We're about to abort(), this memory can never be freed; so it's fine
+        // to just return a raw pointer
+        return result;
+#    endif
+      return str;
+    }();
+
     // If the uncaught exception can be caught with std::exception&
     const __shim_type_info* catch_type =
         static_cast<const __shim_type_info*>(&typeid(std::exception));
@@ -69,19 +68,19 @@ static void demangling_terminate_handler()
     {
         // Include the what() message from the exception
         const std::exception* e = static_cast<const std::exception*>(thrown_object);
-        abort_message("terminating due to %s exception of type %s: %s", cause, name.get(), e->what());
+        __abort_message("terminating due to %s exception of type %s: %s", cause, name, e->what());
     }
     else
     {
         // Else just note that we're terminating due to an exception
-        abort_message("terminating due to %s exception of type %s", cause, name.get());
+        __abort_message("terminating due to %s exception of type %s", cause, name);
     }
 }
 #else // !_LIBCXXABI_NO_EXCEPTIONS
 __attribute__((noreturn))
 static void demangling_terminate_handler()
 {
-    abort_message("terminating");
+    __abort_message("terminating");
 }
 #endif // !_LIBCXXABI_NO_EXCEPTIONS
 
diff --git a/lib/libcxxabi/src/cxa_demangle.cpp b/lib/libcxxabi/src/cxa_demangle.cpp
index bece33a007..4756d83436 100644
--- a/lib/libcxxabi/src/cxa_demangle.cpp
+++ b/lib/libcxxabi/src/cxa_demangle.cpp
@@ -28,10 +28,6 @@
 
 using namespace itanium_demangle;
 
-constexpr const char *itanium_demangle::FloatData<float>::spec;
-constexpr const char *itanium_demangle::FloatData<double>::spec;
-constexpr const char *itanium_demangle::FloatData<long double>::spec;
-
 // <discriminator> := _ <non-negative number>      # when number < 10
 //                 := __ <non-negative number> _   # when number >= 10
 //  extension      := decimal-digit+               # at the end of string
diff --git a/lib/libcxxabi/src/cxa_exception_storage.cpp b/lib/libcxxabi/src/cxa_exception_storage.cpp
index c842da195a..05da6a48e3 100644
--- a/lib/libcxxabi/src/cxa_exception_storage.cpp
+++ b/lib/libcxxabi/src/cxa_exception_storage.cpp
@@ -56,17 +56,17 @@ extern "C" {
 namespace __cxxabiv1 {
 namespace {
     std::__libcpp_tls_key key_;
-    std::__libcpp_exec_once_flag flag_ = _LIBCPP_EXEC_ONCE_INITIALIZER;
+    constinit std::__libcpp_exec_once_flag flag_ = _LIBCPP_EXEC_ONCE_INITIALIZER;
 
     void _LIBCPP_TLS_DESTRUCTOR_CC destruct_(void *p) {
         __free_with_fallback(p);
         if (0 != std::__libcpp_tls_set(key_, NULL))
-            abort_message("cannot zero out thread value for __cxa_get_globals()");
+            __abort_message("cannot zero out thread value for __cxa_get_globals()");
     }
 
     void construct_() {
         if (0 != std::__libcpp_tls_create(&key_, destruct_))
-            abort_message("cannot create thread specific key for __cxa_get_globals()");
+            __abort_message("cannot create thread specific key for __cxa_get_globals()");
     }
 } // namespace
 
@@ -80,9 +80,9 @@ extern "C" {
             retVal = static_cast<__cxa_eh_globals*>(
                 __calloc_with_fallback(1, sizeof(__cxa_eh_globals)));
             if (NULL == retVal)
-                abort_message("cannot allocate __cxa_eh_globals");
+                __abort_message("cannot allocate __cxa_eh_globals");
             if (0 != std::__libcpp_tls_set(key_, retVal))
-               abort_message("std::__libcpp_tls_set failure in __cxa_get_globals()");
+               __abort_message("std::__libcpp_tls_set failure in __cxa_get_globals()");
         }
         return retVal;
     }
@@ -94,7 +94,7 @@ extern "C" {
     __cxa_eh_globals *__cxa_get_globals_fast() {
         // First time through, create the key.
         if (0 != std::__libcpp_execute_once(&flag_, construct_))
-            abort_message("execute once failure in __cxa_get_globals_fast()");
+            __abort_message("execute once failure in __cxa_get_globals_fast()");
         return static_cast<__cxa_eh_globals*>(std::__libcpp_tls_get(key_));
     }
 } // extern "C"
diff --git a/lib/libcxxabi/src/cxa_guard_impl.h b/lib/libcxxabi/src/cxa_guard_impl.h
index 320501cb85..191a589176 100644
--- a/lib/libcxxabi/src/cxa_guard_impl.h
+++ b/lib/libcxxabi/src/cxa_guard_impl.h
@@ -91,7 +91,7 @@
 // the former.
 #ifdef BUILDING_CXA_GUARD
 #  include "abort_message.h"
-#  define ABORT_WITH_MESSAGE(...) ::abort_message(__VA_ARGS__)
+#  define ABORT_WITH_MESSAGE(...) ::__abort_message(__VA_ARGS__)
 #elif defined(TESTING_CXA_GUARD)
 #  define ABORT_WITH_MESSAGE(...) ::abort()
 #else
@@ -156,12 +156,12 @@ private:
 //                       PlatformGetThreadID
 //===----------------------------------------------------------------------===//
 
-#if defined(__APPLE__) && defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
+#if defined(__APPLE__) && _LIBCPP_HAS_THREAD_API_PTHREAD
 uint32_t PlatformThreadID() {
   static_assert(sizeof(mach_port_t) == sizeof(uint32_t), "");
   return static_cast<uint32_t>(pthread_mach_thread_np(std::__libcpp_thread_get_current_id()));
 }
-#elif defined(SYS_gettid) && defined(_LIBCPP_HAS_THREAD_API_PTHREAD)
+#elif defined(SYS_gettid) && _LIBCPP_HAS_THREAD_API_PTHREAD
 uint32_t PlatformThreadID() {
   static_assert(sizeof(pid_t) == sizeof(uint32_t), "");
   return static_cast<uint32_t>(syscall(SYS_gettid));
@@ -676,8 +676,8 @@ static_assert(CurrentImplementation != Implementation::Futex || PlatformSupports
 
 using SelectedImplementation = SelectImplementation<CurrentImplementation>::type;
 
-} // end namespace
-} // end namespace __cxxabiv1
+} // namespace
+} // namespace __cxxabiv1
 
 #if defined(__clang__)
 #  pragma clang diagnostic pop
diff --git a/lib/libcxxabi/src/cxa_handlers.cpp b/lib/libcxxabi/src/cxa_handlers.cpp
index 344250dde0..f879ff0d8f 100644
--- a/lib/libcxxabi/src/cxa_handlers.cpp
+++ b/lib/libcxxabi/src/cxa_handlers.cpp
@@ -33,7 +33,7 @@ __unexpected(unexpected_handler func)
 {
     func();
     // unexpected handler should not return
-    abort_message("unexpected_handler unexpectedly returned");
+    __abort_message("unexpected_handler unexpectedly returned");
 }
 
 __attribute__((noreturn))
@@ -58,13 +58,13 @@ __terminate(terminate_handler func) noexcept
 #endif // _LIBCXXABI_NO_EXCEPTIONS
         func();
         // handler should not return
-        abort_message("terminate_handler unexpectedly returned");
+        __abort_message("terminate_handler unexpectedly returned");
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
     }
     catch (...)
     {
         // handler should not throw exception
-        abort_message("terminate_handler unexpectedly threw an exception");
+        __abort_message("terminate_handler unexpectedly threw an exception");
     }
 #endif // _LIBCXXABI_NO_EXCEPTIONS
 }
diff --git a/lib/libcxxabi/src/cxa_personality.cpp b/lib/libcxxabi/src/cxa_personality.cpp
index 843a18a4cb..5f6e75c5be 100644
--- a/lib/libcxxabi/src/cxa_personality.cpp
+++ b/lib/libcxxabi/src/cxa_personality.cpp
@@ -167,7 +167,7 @@ uintptr_t readPointerHelper(const uint8_t*& p) {
     return static_cast<uintptr_t>(value);
 }
 
-} // end namespace
+} // namespace
 
 extern "C"
 {
diff --git a/lib/libcxxabi/src/cxa_thread_atexit.cpp b/lib/libcxxabi/src/cxa_thread_atexit.cpp
index c6bd0aa323..8546cfe48c 100644
--- a/lib/libcxxabi/src/cxa_thread_atexit.cpp
+++ b/lib/libcxxabi/src/cxa_thread_atexit.cpp
@@ -89,7 +89,7 @@ namespace {
       // __cxa_thread_atexit() may be called arbitrarily late (for example, from
       // global destructors or atexit() handlers).
       if (std::__libcpp_tls_create(&dtors_key, run_dtors) != 0) {
-        abort_message("std::__libcpp_tls_create() failed in __cxa_thread_atexit()");
+        __abort_message("std::__libcpp_tls_create() failed in __cxa_thread_atexit()");
       }
     }
 
diff --git a/lib/libcxxabi/src/cxa_vector.cpp b/lib/libcxxabi/src/cxa_vector.cpp
index 17d942a6e6..857ee27d06 100644
--- a/lib/libcxxabi/src/cxa_vector.cpp
+++ b/lib/libcxxabi/src/cxa_vector.cpp
@@ -121,7 +121,7 @@ void throw_bad_array_new_length() {
 #ifndef _LIBCXXABI_NO_EXCEPTIONS
   throw std::bad_array_new_length();
 #else
-  abort_message("__cxa_vec_new failed to allocate memory");
+  __abort_message("__cxa_vec_new failed to allocate memory");
 #endif
 }
 
diff --git a/lib/libcxxabi/src/cxa_virtual.cpp b/lib/libcxxabi/src/cxa_virtual.cpp
index c868672e00..8f4fdd0919 100644
--- a/lib/libcxxabi/src/cxa_virtual.cpp
+++ b/lib/libcxxabi/src/cxa_virtual.cpp
@@ -13,12 +13,12 @@ namespace __cxxabiv1 {
 extern "C" {
 _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN
 void __cxa_pure_virtual(void) {
-  abort_message("Pure virtual function called!");
+  __abort_message("Pure virtual function called!");
 }
 
 _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN
 void __cxa_deleted_virtual(void) {
-  abort_message("Deleted virtual function called!");
+  __abort_message("Deleted virtual function called!");
 }
 } // extern "C"
 } // abi
diff --git a/lib/libcxxabi/src/demangle/DemangleConfig.h b/lib/libcxxabi/src/demangle/DemangleConfig.h
index d67d89bdb0..06fd223f55 100644
--- a/lib/libcxxabi/src/demangle/DemangleConfig.h
+++ b/lib/libcxxabi/src/demangle/DemangleConfig.h
@@ -15,7 +15,7 @@
 // build systems to override this value.
 // https://libcxx.llvm.org/UsingLibcxx.html#enabling-the-safe-libc-mode
 #ifndef _LIBCPP_VERBOSE_ABORT
-#define _LIBCPP_VERBOSE_ABORT(...) abort_message(__VA_ARGS__)
+#define _LIBCPP_VERBOSE_ABORT(...) __abort_message(__VA_ARGS__)
 #include "../abort_message.h"
 #endif
 
diff --git a/lib/libcxxabi/src/demangle/ItaniumDemangle.h b/lib/libcxxabi/src/demangle/ItaniumDemangle.h
index 36bf454636..3df41b5f4d 100644
--- a/lib/libcxxabi/src/demangle/ItaniumDemangle.h
+++ b/lib/libcxxabi/src/demangle/ItaniumDemangle.h
@@ -19,7 +19,6 @@
 #include "DemangleConfig.h"
 #include "StringViewExtras.h"
 #include "Utility.h"
-#include <__cxxabi_config.h>
 #include <algorithm>
 #include <cctype>
 #include <cstdio>
@@ -31,7 +30,7 @@
 #include <type_traits>
 #include <utility>
 
-#ifdef _LIBCXXABI_COMPILER_CLANG
+#if defined(__clang__)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wunused-template"
 #endif
@@ -157,6 +156,8 @@ public:
   }
 };
 
+class NodeArray;
+
 // Base class of all AST nodes. The AST is built by the parser, then is
 // traversed by the printLeft/Right functions to produce a demangled string.
 class Node {
@@ -200,8 +201,7 @@ private:
 
   Prec Precedence : 6;
 
-  // FIXME: Make these protected.
-public:
+protected:
   /// Tracks if this node has a component on its right side, in which case we
   /// need to call printRight.
   Cache RHSComponentCache : 2;
@@ -255,6 +255,9 @@ public:
   Kind getKind() const { return K; }
 
   Prec getPrecedence() const { return Precedence; }
+  Cache getRHSComponentCache() const { return RHSComponentCache; }
+  Cache getArrayCache() const { return ArrayCache; }
+  Cache getFunctionCache() const { return FunctionCache; }
 
   virtual bool hasRHSComponentSlow(OutputBuffer &) const { return false; }
   virtual bool hasArraySlow(OutputBuffer &) const { return false; }
@@ -292,6 +295,13 @@ public:
   // implementation.
   virtual void printRight(OutputBuffer &) const {}
 
+  // Print an initializer list of this type. Returns true if we printed a custom
+  // representation, false if nothing has been printed and the default
+  // representation should be used.
+  virtual bool printInitListAsType(OutputBuffer &, const NodeArray &) const {
+    return false;
+  }
+
   virtual std::string_view getBaseName() const { return {}; }
 
   // Silence compiler warnings, this dtor will never be called.
@@ -338,6 +348,10 @@ public:
       FirstElement = false;
     }
   }
+
+  // Print an array of integer literals as a string literal. Returns whether we
+  // could do so.
+  bool printAsString(OutputBuffer &OB) const;
 };
 
 struct NodeArrayNode : Node {
@@ -424,8 +438,8 @@ protected:
 
 public:
   QualType(const Node *Child_, Qualifiers Quals_)
-      : Node(KQualType, Child_->RHSComponentCache,
-             Child_->ArrayCache, Child_->FunctionCache),
+      : Node(KQualType, Child_->getRHSComponentCache(), Child_->getArrayCache(),
+             Child_->getFunctionCache()),
         Quals(Quals_), Child(Child_) {}
 
   Qualifiers getQuals() const { return Quals; }
@@ -554,8 +568,8 @@ struct AbiTagAttr : Node {
   std::string_view Tag;
 
   AbiTagAttr(Node *Base_, std::string_view Tag_)
-      : Node(KAbiTagAttr, Base_->RHSComponentCache, Base_->ArrayCache,
-             Base_->FunctionCache),
+      : Node(KAbiTagAttr, Base_->getRHSComponentCache(), Base_->getArrayCache(),
+             Base_->getFunctionCache()),
         Base(Base_), Tag(Tag_) {}
 
   template<typename Fn> void match(Fn F) const { F(Base, Tag); }
@@ -615,7 +629,7 @@ class PointerType final : public Node {
 
 public:
   PointerType(const Node *Pointee_)
-      : Node(KPointerType, Pointee_->RHSComponentCache),
+      : Node(KPointerType, Pointee_->getRHSComponentCache()),
         Pointee(Pointee_) {}
 
   const Node *getPointee() const { return Pointee; }
@@ -699,7 +713,7 @@ class ReferenceType : public Node {
 
 public:
   ReferenceType(const Node *Pointee_, ReferenceKind RK_)
-      : Node(KReferenceType, Pointee_->RHSComponentCache),
+      : Node(KReferenceType, Pointee_->getRHSComponentCache()),
         Pointee(Pointee_), RK(RK_) {}
 
   template<typename Fn> void match(Fn F) const { F(Pointee, RK); }
@@ -742,7 +756,7 @@ class PointerToMemberType final : public Node {
 
 public:
   PointerToMemberType(const Node *ClassType_, const Node *MemberType_)
-      : Node(KPointerToMemberType, MemberType_->RHSComponentCache),
+      : Node(KPointerToMemberType, MemberType_->getRHSComponentCache()),
         ClassType(ClassType_), MemberType(MemberType_) {}
 
   template<typename Fn> void match(Fn F) const { F(ClassType, MemberType); }
@@ -795,6 +809,15 @@ public:
     OB += "]";
     Base->printRight(OB);
   }
+
+  bool printInitListAsType(OutputBuffer &OB,
+                           const NodeArray &Elements) const override {
+    if (Base->getKind() == KNameType &&
+        static_cast<const NameType *>(Base)->getName() == "char") {
+      return Elements.printAsString(OB);
+    }
+    return false;
+  }
 };
 
 class FunctionType final : public Node {
@@ -1383,16 +1406,14 @@ class ParameterPack final : public Node {
 public:
   ParameterPack(NodeArray Data_) : Node(KParameterPack), Data(Data_) {
     ArrayCache = FunctionCache = RHSComponentCache = Cache::Unknown;
-    if (std::all_of(Data.begin(), Data.end(), [](Node* P) {
-          return P->ArrayCache == Cache::No;
-        }))
+    if (std::all_of(Data.begin(), Data.end(),
+                    [](Node *P) { return P->getArrayCache() == Cache::No; }))
       ArrayCache = Cache::No;
-    if (std::all_of(Data.begin(), Data.end(), [](Node* P) {
-          return P->FunctionCache == Cache::No;
-        }))
+    if (std::all_of(Data.begin(), Data.end(),
+                    [](Node *P) { return P->getFunctionCache() == Cache::No; }))
       FunctionCache = Cache::No;
-    if (std::all_of(Data.begin(), Data.end(), [](Node* P) {
-          return P->RHSComponentCache == Cache::No;
+    if (std::all_of(Data.begin(), Data.end(), [](Node *P) {
+          return P->getRHSComponentCache() == Cache::No;
         }))
       RHSComponentCache = Cache::No;
   }
@@ -2056,17 +2077,23 @@ public:
 class CallExpr : public Node {
   const Node *Callee;
   NodeArray Args;
+  bool IsParen; // (func)(args ...) ?
 
 public:
-  CallExpr(const Node *Callee_, NodeArray Args_, Prec Prec_)
-      : Node(KCallExpr, Prec_), Callee(Callee_), Args(Args_) {}
+  CallExpr(const Node *Callee_, NodeArray Args_, bool IsParen_, Prec Prec_)
+      : Node(KCallExpr, Prec_), Callee(Callee_), Args(Args_),
+        IsParen(IsParen_) {}
 
   template <typename Fn> void match(Fn F) const {
-    F(Callee, Args, getPrecedence());
+    F(Callee, Args, IsParen, getPrecedence());
   }
 
   void printLeft(OutputBuffer &OB) const override {
+    if (IsParen)
+      OB.printOpen();
     Callee->print(OB);
+    if (IsParen)
+      OB.printClose();
     OB.printOpen();
     Args.printWithComma(OB);
     OB.printClose();
@@ -2226,8 +2253,11 @@ public:
   template<typename Fn> void match(Fn F) const { F(Ty, Inits); }
 
   void printLeft(OutputBuffer &OB) const override {
-    if (Ty)
+    if (Ty) {
+      if (Ty->printInitListAsType(OB, Inits))
+        return;
       Ty->print(OB);
+    }
     OB += '{';
     Inits.printWithComma(OB);
     OB += '}';
@@ -2434,6 +2464,8 @@ public:
     if (Type.size() <= 3)
       OB += Type;
   }
+
+  std::string_view value() const { return Value; }
 };
 
 class RequiresExpr : public Node {
@@ -2605,6 +2637,94 @@ template<typename NodeT> struct NodeKind;
   };
 #include "ItaniumNodes.def"
 
+inline bool NodeArray::printAsString(OutputBuffer &OB) const {
+  auto StartPos = OB.getCurrentPosition();
+  auto Fail = [&OB, StartPos] {
+    OB.setCurrentPosition(StartPos);
+    return false;
+  };
+
+  OB += '"';
+  bool LastWasNumericEscape = false;
+  for (const Node *Element : *this) {
+    if (Element->getKind() != Node::KIntegerLiteral)
+      return Fail();
+    int integer_value = 0;
+    for (char c : static_cast<const IntegerLiteral *>(Element)->value()) {
+      if (c < '0' || c > '9' || integer_value > 25)
+        return Fail();
+      integer_value *= 10;
+      integer_value += c - '0';
+    }
+    if (integer_value > 255)
+      return Fail();
+
+    // Insert a `""` to avoid accidentally extending a numeric escape.
+    if (LastWasNumericEscape) {
+      if ((integer_value >= '0' && integer_value <= '9') ||
+          (integer_value >= 'a' && integer_value <= 'f') ||
+          (integer_value >= 'A' && integer_value <= 'F')) {
+        OB += "\"\"";
+      }
+    }
+
+    LastWasNumericEscape = false;
+
+    // Determine how to print this character.
+    switch (integer_value) {
+    case '\a':
+      OB += "\\a";
+      break;
+    case '\b':
+      OB += "\\b";
+      break;
+    case '\f':
+      OB += "\\f";
+      break;
+    case '\n':
+      OB += "\\n";
+      break;
+    case '\r':
+      OB += "\\r";
+      break;
+    case '\t':
+      OB += "\\t";
+      break;
+    case '\v':
+      OB += "\\v";
+      break;
+
+    case '"':
+      OB += "\\\"";
+      break;
+    case '\\':
+      OB += "\\\\";
+      break;
+
+    default:
+      // We assume that the character is ASCII, and use a numeric escape for all
+      // remaining non-printable ASCII characters.
+      if (integer_value < 32 || integer_value == 127) {
+        constexpr char Hex[] = "0123456789ABCDEF";
+        OB += '\\';
+        if (integer_value > 7)
+          OB += 'x';
+        if (integer_value >= 16)
+          OB += Hex[integer_value >> 4];
+        OB += Hex[integer_value & 0xF];
+        LastWasNumericEscape = true;
+        break;
+      }
+
+      // Assume all remaining characters are directly printable.
+      OB += (char)integer_value;
+      break;
+    }
+  }
+  OB += '"';
+  return true;
+}
+
 template <typename Derived, typename Alloc> struct AbstractManglingParser {
   const char *First;
   const char *Last;
@@ -2678,7 +2798,7 @@ template <typename Derived, typename Alloc> struct AbstractManglingParser {
 
   bool TryToParseTemplateArgs = true;
   bool PermitForwardTemplateReferences = false;
-  bool InConstraintExpr = false;
+  bool HasIncompleteTemplateParameterTracking = false;
   size_t ParsingLambdaParamsAtLevel = (size_t)-1;
 
   unsigned NumSyntheticTemplateParameters[3] = {};
@@ -3240,9 +3360,12 @@ const typename AbstractManglingParser<
      "operator co_await"},
     {"az", OperatorInfo::OfIdOp, /*Type*/ false, Node::Prec::Unary, "alignof "},
     {"cc", OperatorInfo::NamedCast, false, Node::Prec::Postfix, "const_cast"},
-    {"cl", OperatorInfo::Call, false, Node::Prec::Postfix, "operator()"},
+    {"cl", OperatorInfo::Call, /*Paren*/ false, Node::Prec::Postfix,
+     "operator()"},
     {"cm", OperatorInfo::Binary, false, Node::Prec::Comma, "operator,"},
     {"co", OperatorInfo::Prefix, false, Node::Prec::Unary, "operator~"},
+    {"cp", OperatorInfo::Call, /*Paren*/ true, Node::Prec::Postfix,
+     "operator()"},
     {"cv", OperatorInfo::CCast, false, Node::Prec::Cast, "operator"}, // C Cast
     {"dV", OperatorInfo::Binary, false, Node::Prec::Assign, "operator/="},
     {"da", OperatorInfo::Del, /*Ary*/ true, Node::Prec::Unary,
@@ -3319,7 +3442,7 @@ AbstractManglingParser<Derived, Alloc>::parseOperatorEncoding() {
     return nullptr;
 
   // We can't use lower_bound as that can link to symbols in the C++ library,
-  // and this must remain independant of that.
+  // and this must remain independent of that.
   size_t lower = 0u, upper = NumOps - 1; // Inclusive bounds.
   while (upper != lower) {
     size_t middle = (upper + lower) / 2;
@@ -4207,9 +4330,12 @@ Node *AbstractManglingParser<Derived, Alloc>::parseType() {
     case 'h':
       First += 2;
       return make<NameType>("half");
-    //                ::= DF <number> _ # ISO/IEC TS 18661 binary floating point (N bits)
+    //       ::= DF16b         # C++23 std::bfloat16_t
+    //       ::= DF <number> _ # ISO/IEC TS 18661 binary floating point (N bits)
     case 'F': {
       First += 2;
+      if (consumeIf("16b"))
+        return make<NameType>("std::bfloat16_t");
       Node *DimensionNumber = make<NameType>(parseNumber());
       if (!DimensionNumber)
         return nullptr;
@@ -4217,6 +4343,101 @@ Node *AbstractManglingParser<Derived, Alloc>::parseType() {
         return nullptr;
       return make<BinaryFPType>(DimensionNumber);
     }
+    //                ::= [DS] DA  # N1169 fixed-point [_Sat] T _Accum
+    //                ::= [DS] DR  # N1169 fixed-point [_Sat] T _Frac
+    // <fixed-point-size>
+    //                ::= s # short
+    //                ::= t # unsigned short
+    //                ::= i # plain
+    //                ::= j # unsigned
+    //                ::= l # long
+    //                ::= m # unsigned long
+    case 'A': {
+      char c = look(2);
+      First += 3;
+      switch (c) {
+      case 's':
+        return make<NameType>("short _Accum");
+      case 't':
+        return make<NameType>("unsigned short _Accum");
+      case 'i':
+        return make<NameType>("_Accum");
+      case 'j':
+        return make<NameType>("unsigned _Accum");
+      case 'l':
+        return make<NameType>("long _Accum");
+      case 'm':
+        return make<NameType>("unsigned long _Accum");
+      default:
+        return nullptr;
+      }
+    }
+    case 'R': {
+      char c = look(2);
+      First += 3;
+      switch (c) {
+      case 's':
+        return make<NameType>("short _Fract");
+      case 't':
+        return make<NameType>("unsigned short _Fract");
+      case 'i':
+        return make<NameType>("_Fract");
+      case 'j':
+        return make<NameType>("unsigned _Fract");
+      case 'l':
+        return make<NameType>("long _Fract");
+      case 'm':
+        return make<NameType>("unsigned long _Fract");
+      default:
+        return nullptr;
+      }
+    }
+    case 'S': {
+      First += 2;
+      if (look() != 'D')
+        return nullptr;
+      if (look(1) == 'A') {
+        char c = look(2);
+        First += 3;
+        switch (c) {
+        case 's':
+          return make<NameType>("_Sat short _Accum");
+        case 't':
+          return make<NameType>("_Sat unsigned short _Accum");
+        case 'i':
+          return make<NameType>("_Sat _Accum");
+        case 'j':
+          return make<NameType>("_Sat unsigned _Accum");
+        case 'l':
+          return make<NameType>("_Sat long _Accum");
+        case 'm':
+          return make<NameType>("_Sat unsigned long _Accum");
+        default:
+          return nullptr;
+        }
+      }
+      if (look(1) == 'R') {
+        char c = look(2);
+        First += 3;
+        switch (c) {
+        case 's':
+          return make<NameType>("_Sat short _Fract");
+        case 't':
+          return make<NameType>("_Sat unsigned short _Fract");
+        case 'i':
+          return make<NameType>("_Sat _Fract");
+        case 'j':
+          return make<NameType>("_Sat unsigned _Fract");
+        case 'l':
+          return make<NameType>("_Sat long _Fract");
+        case 'm':
+          return make<NameType>("_Sat unsigned long _Fract");
+        default:
+          return nullptr;
+        }
+      }
+      return nullptr;
+    }
     //                ::= DB <number> _                             # C23 signed _BitInt(N)
     //                ::= DB <instantiation-dependent expression> _ # C23 signed _BitInt(N)
     //                ::= DU <number> _                             # C23 unsigned _BitInt(N)
@@ -4337,6 +4558,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseType() {
     // parse them, take the second production.
 
     if (TryToParseTemplateArgs && look() == 'I') {
+      Subs.push_back(Result);
       Node *TA = getDerived().parseTemplateArgs();
       if (TA == nullptr)
         return nullptr;
@@ -4819,7 +5041,8 @@ template <typename Derived, typename Alloc>
 Node *AbstractManglingParser<Derived, Alloc>::parseConstraintExpr() {
   // Within this expression, all enclosing template parameter lists are in
   // scope.
-  ScopedOverride<bool> SaveInConstraintExpr(InConstraintExpr, true);
+  ScopedOverride<bool> SaveIncompleteTemplateParameterTracking(
+      HasIncompleteTemplateParameterTracking, true);
   return getDerived().parseExpr();
 }
 
@@ -4888,6 +5111,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseRequiresExpr() {
 //              ::= <binary operator-name> <expression> <expression>
 //              ::= <ternary operator-name> <expression> <expression> <expression>
 //              ::= cl <expression>+ E                                   # call
+//              ::= cp <base-unresolved-name> <expression>* E            # (name) (expr-list), call that would use argument-dependent lookup but for the parentheses
 //              ::= cv <type> <expression>                               # conversion with one argument
 //              ::= cv <type> _ <expression>* E                          # conversion with a different number of arguments
 //              ::= [gs] nw <expression>* _ <type> E                     # new (expr-list) type
@@ -5023,7 +5247,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseExpr() {
         Names.push_back(E);
       }
       return make<CallExpr>(Callee, popTrailingNodeArray(ExprsBegin),
-                            Op->getPrecedence());
+                            /*IsParen=*/Op->getFlag(), Op->getPrecedence());
     }
     case OperatorInfo::CCast: {
       // C Cast: (type)expr
@@ -5210,7 +5434,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseExpr() {
       }
     }
     return make<CallExpr>(Name, popTrailingNodeArray(ExprsBegin),
-                          Node::Prec::Postfix);
+                          /*IsParen=*/false, Node::Prec::Postfix);
   }
 
   // Only unresolved names remain.
@@ -5677,7 +5901,7 @@ Node *AbstractManglingParser<Derived, Alloc>::parseTemplateParam() {
   // substitute them all within a <constraint-expression>, so print the
   // parameter numbering instead for now.
   // TODO: Track all enclosing template parameters and substitute them here.
-  if (InConstraintExpr) {
+  if (HasIncompleteTemplateParameterTracking) {
     return make<NameType>(std::string_view(Begin, First - 1 - Begin));
   }
 
@@ -5738,6 +5962,12 @@ Node *AbstractManglingParser<Derived, Alloc>::parseTemplateParamDecl(
   }
 
   if (consumeIf("Tk")) {
+    // We don't track enclosing template parameter levels well enough to
+    // reliably demangle template parameter substitutions, so print an arbitrary
+    // string in place of a parameter for now.
+    // TODO: Track all enclosing template parameters and demangle substitutions.
+    ScopedOverride<bool> SaveIncompleteTemplateParameterTrackingExpr(
+        HasIncompleteTemplateParameterTracking, true);
     Node *Constraint = getDerived().parseName();
     if (!Constraint)
       return nullptr;
@@ -5948,7 +6178,7 @@ struct ManglingParser : AbstractManglingParser<ManglingParser<Alloc>, Alloc> {
 
 DEMANGLE_NAMESPACE_END
 
-#ifdef _LIBCXXABI_COMPILER_CLANG
+#if defined(__clang__)
 #pragma clang diagnostic pop
 #endif
 
diff --git a/lib/libcxxabi/src/fallback_malloc.cpp b/lib/libcxxabi/src/fallback_malloc.cpp
index 76bd2e9bcd..75788fe9be 100644
--- a/lib/libcxxabi/src/fallback_malloc.cpp
+++ b/lib/libcxxabi/src/fallback_malloc.cpp
@@ -259,7 +259,7 @@ void* __aligned_malloc_with_fallback(size_t size) {
 #if defined(_WIN32)
   if (void* dest = std::__libcpp_aligned_alloc(alignof(__aligned_type), size))
     return dest;
-#elif defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION)
+#elif !_LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
   if (void* dest = ::malloc(size))
     return dest;
 #else
@@ -286,7 +286,7 @@ void __aligned_free_with_fallback(void* ptr) {
   if (is_fallback_ptr(ptr))
     fallback_free(ptr);
   else {
-#if defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION)
+#if !_LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
     ::free(ptr);
 #else
     std::__libcpp_aligned_free(ptr);
diff --git a/lib/libcxxabi/src/private_typeinfo.cpp b/lib/libcxxabi/src/private_typeinfo.cpp
index 9dba91e198..01a1d2603b 100644
--- a/lib/libcxxabi/src/private_typeinfo.cpp
+++ b/lib/libcxxabi/src/private_typeinfo.cpp
@@ -41,9 +41,11 @@
 // Defining _LIBCXXABI_FORGIVING_DYNAMIC_CAST does not help since can_catch() calls
 // is_equal() with use_strcmp=false so the string names are not compared.
 
-#include <cstdint>
 #include <cassert>
+#include <cstddef>
+#include <cstdint>
 #include <string.h>
+
 #include "abort_message.h"
 
 #ifdef _LIBCXXABI_FORGIVING_DYNAMIC_CAST
@@ -589,10 +591,9 @@ __base_class_type_info::has_unambiguous_public_base(__dynamic_cast_info* info,
     // .. and reset the pointer.
     adjustedPtr = nullptr;
   }
-    __base_type->has_unambiguous_public_base(
-            info,
-            static_cast<char*>(adjustedPtr) + offset_to_base,
-            (__offset_flags & __public_mask) ? path_below : not_public_path);
+  __base_type->has_unambiguous_public_base(
+      info, reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(adjustedPtr) + offset_to_base),
+      (__offset_flags & __public_mask) ? path_below : not_public_path);
 }
 
 void
diff --git a/lib/libcxxabi/src/stdlib_new_delete.cpp b/lib/libcxxabi/src/stdlib_new_delete.cpp
index b802559d47..f386b28f0c 100644
--- a/lib/libcxxabi/src/stdlib_new_delete.cpp
+++ b/lib/libcxxabi/src/stdlib_new_delete.cpp
@@ -24,22 +24,22 @@
 #  error The _LIBCPP_WEAK macro should be already defined by libc++
 #endif
 
-#if defined(_LIBCXXABI_NO_EXCEPTIONS) != defined(_LIBCPP_HAS_NO_EXCEPTIONS)
+#if defined(_LIBCXXABI_NO_EXCEPTIONS) != !_LIBCPP_HAS_EXCEPTIONS
 #  error libc++ and libc++abi seem to disagree on whether exceptions are enabled
 #endif
 
 inline void __throw_bad_alloc_shim() {
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   throw std::bad_alloc();
 #else
-  abort_message("bad_alloc was thrown in -fno-exceptions mode");
+  __abort_message("bad_alloc was thrown in -fno-exceptions mode");
 #endif
 }
 
 #define _LIBCPP_ASSERT_SHIM(expr, str)                                                                                 \
   do {                                                                                                                 \
     if (!expr)                                                                                                         \
-      abort_message(str);                                                                                              \
+      __abort_message(str);                                                                                            \
   } while (false)
 
 // ------------------ BEGIN COPY ------------------
@@ -71,7 +71,7 @@ _LIBCPP_MAKE_OVERRIDABLE_FUNCTION_DETECTABLE _LIBCPP_WEAK void* operator new(std
 }
 
 _LIBCPP_WEAK void* operator new(size_t size, const std::nothrow_t&) noexcept {
-#ifdef _LIBCPP_HAS_NO_EXCEPTIONS
+#if !_LIBCPP_HAS_EXCEPTIONS
 #  if _LIBCPP_CAN_DETECT_OVERRIDDEN_FUNCTION
   _LIBCPP_ASSERT_SHIM(
       !std::__is_function_overridden(static_cast<void* (*)(std::size_t)>(&operator new)),
@@ -99,7 +99,7 @@ _LIBCPP_MAKE_OVERRIDABLE_FUNCTION_DETECTABLE _LIBCPP_WEAK void* operator new[](s
 }
 
 _LIBCPP_WEAK void* operator new[](size_t size, const std::nothrow_t&) noexcept {
-#ifdef _LIBCPP_HAS_NO_EXCEPTIONS
+#if !_LIBCPP_HAS_EXCEPTIONS
 #  if _LIBCPP_CAN_DETECT_OVERRIDDEN_FUNCTION
   _LIBCPP_ASSERT_SHIM(
       !std::__is_function_overridden(static_cast<void* (*)(std::size_t)>(&operator new[])),
@@ -134,7 +134,7 @@ _LIBCPP_WEAK void operator delete[](void* ptr, const std::nothrow_t&) noexcept {
 
 _LIBCPP_WEAK void operator delete[](void* ptr, size_t) noexcept { ::operator delete[](ptr); }
 
-#if !defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION)
+#if _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
 
 static void* operator_new_aligned_impl(std::size_t size, std::align_val_t alignment) {
   if (size == 0)
@@ -165,7 +165,7 @@ operator new(std::size_t size, std::align_val_t alignment) _THROW_BAD_ALLOC {
 }
 
 _LIBCPP_WEAK void* operator new(size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept {
-#  ifdef _LIBCPP_HAS_NO_EXCEPTIONS
+#  if !_LIBCPP_HAS_EXCEPTIONS
 #    if _LIBCPP_CAN_DETECT_OVERRIDDEN_FUNCTION
   _LIBCPP_ASSERT_SHIM(
       !std::__is_function_overridden(static_cast<void* (*)(std::size_t, std::align_val_t)>(&operator new)),
@@ -194,7 +194,7 @@ operator new[](size_t size, std::align_val_t alignment) _THROW_BAD_ALLOC {
 }
 
 _LIBCPP_WEAK void* operator new[](size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept {
-#  ifdef _LIBCPP_HAS_NO_EXCEPTIONS
+#  if !_LIBCPP_HAS_EXCEPTIONS
 #    if _LIBCPP_CAN_DETECT_OVERRIDDEN_FUNCTION
   _LIBCPP_ASSERT_SHIM(
       !std::__is_function_overridden(static_cast<void* (*)(std::size_t, std::align_val_t)>(&operator new[])),
@@ -240,5 +240,5 @@ _LIBCPP_WEAK void operator delete[](void* ptr, size_t, std::align_val_t alignmen
   ::operator delete[](ptr, alignment);
 }
 
-#endif // !_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
+#endif // _LIBCPP_HAS_LIBRARY_ALIGNED_ALLOCATION
 // ------------------ END COPY ------------------