[libc++][RFC] Always define internal feature test macros (#89178)

Currently, the library-internal feature test macros are only defined if
the feature is not available, and always have the prefix
`_LIBCPP_HAS_NO_`. This patch changes that, so that they are always
defined and have the prefix `_LIBCPP_HAS_` instead. This changes the
canonical use of these macros to `#if _LIBCPP_HAS_FEATURE`, which means
that using an undefined macro (e.g. due to a missing include) is
diagnosed now. While this is rather unlikely currently, a similar change
in `<__configuration/availability.h>` caught a few bugs. This also
improves readability, since it removes the double-negation of `#ifndef
_LIBCPP_HAS_NO_FEATURE`.

The current patch only touches the macros defined in `<__config>`. If
people are happy with this approach, I'll make a follow-up PR to also
change the macros defined in `<__config_site>`.

17 files changed, 64 insertions, 64 deletions

diff --git a/libcxx/src/condition_variable_destructor.cpp b/libcxx/src/condition_variable_destructor.cpp
index 59811ed..f6ffe33 100644
--- a/libcxx/src/condition_variable_destructor.cpp
+++ b/libcxx/src/condition_variable_destructor.cpp
@@ -14,7 +14,7 @@
 #include <__config>
 #include <__thread/support.h>
 
-#if _LIBCPP_ABI_VERSION == 1 || !defined(_LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION)
+#if _LIBCPP_ABI_VERSION == 1 || !_LIBCPP_HAS_TRIVIAL_CONDVAR_DESTRUCTION
 #  define NEEDS_CONDVAR_DESTRUCTOR
 #endif
 
diff --git a/libcxx/src/filesystem/error.h b/libcxx/src/filesystem/error.h
index 09020fb..07ba7fc 100644
--- a/libcxx/src/filesystem/error.h
+++ b/libcxx/src/filesystem/error.h
@@ -186,16 +186,16 @@ struct ErrorHandler {
   T report(const error_code& ec, const char* msg, ...) const {
     va_list ap;
     va_start(ap, msg);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
     try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
       report_impl(ec, msg, ap);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
     } catch (...) {
       va_end(ap);
       throw;
     }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
     va_end(ap);
     return error_value<T>();
   }
@@ -206,16 +206,16 @@ struct ErrorHandler {
   T report(errc const& err, const char* msg, ...) const {
     va_list ap;
     va_start(ap, msg);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
     try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
       report_impl(make_error_code(err), msg, ap);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
     } catch (...) {
       va_end(ap);
       throw;
     }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
     va_end(ap);
     return error_value<T>();
   }
diff --git a/libcxx/src/filesystem/format_string.h b/libcxx/src/filesystem/format_string.h
index 81c5a95..ad6c575 100644
--- a/libcxx/src/filesystem/format_string.h
+++ b/libcxx/src/filesystem/format_string.h
@@ -56,16 +56,16 @@ inline _LIBCPP_ATTRIBUTE_FORMAT(__printf__, 1, 2) string format_string(const cha
   string ret;
   va_list ap;
   va_start(ap, msg);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
     ret = detail::vformat_string(msg, ap);
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   } catch (...) {
     va_end(ap);
     throw;
   }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
   va_end(ap);
   return ret;
 }
diff --git a/libcxx/src/filesystem/int128_builtins.cpp b/libcxx/src/filesystem/int128_builtins.cpp
index 72b7cb4..da6f39e 100644
--- a/libcxx/src/filesystem/int128_builtins.cpp
+++ b/libcxx/src/filesystem/int128_builtins.cpp
@@ -16,7 +16,7 @@
 #include <__config>
 #include <climits>
 
-#if !defined(_LIBCPP_HAS_NO_INT128)
+#if _LIBCPP_HAS_INT128
 
 extern "C" __attribute__((no_sanitize("undefined"))) _LIBCPP_EXPORTED_FROM_ABI __int128_t
 __muloti4(__int128_t a, __int128_t b, int* overflow) {
diff --git a/libcxx/src/future.cpp b/libcxx/src/future.cpp
index e2c14c8..04e6fb8 100644
--- a/libcxx/src/future.cpp
+++ b/libcxx/src/future.cpp
@@ -142,10 +142,10 @@ promise<void>::promise() : __state_(new __assoc_sub_state) {}
 
 promise<void>::~promise() {
   if (__state_) {
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
     if (!__state_->__has_value() && __state_->use_count() > 1)
       __state_->set_exception(make_exception_ptr(future_error(future_errc::broken_promise)));
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
     __state_->__release_shared();
   }
 }
diff --git a/libcxx/src/ios.cpp b/libcxx/src/ios.cpp
index a727855..74d33b4 100644
--- a/libcxx/src/ios.cpp
+++ b/libcxx/src/ios.cpp
@@ -361,18 +361,18 @@ void ios_base::swap(ios_base& rhs) noexcept {
 
 void ios_base::__set_badbit_and_consider_rethrow() {
   __rdstate_ |= badbit;
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   if (__exceptions_ & badbit)
     throw;
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
 }
 
 void ios_base::__set_failbit_and_consider_rethrow() {
   __rdstate_ |= failbit;
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   if (__exceptions_ & failbit)
     throw;
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
 }
 
 bool ios_base::sync_with_stdio(bool sync) {
diff --git a/libcxx/src/locale.cpp b/libcxx/src/locale.cpp
index 484963d..99a2d50 100644
--- a/libcxx/src/locale.cpp
+++ b/libcxx/src/locale.cpp
@@ -174,7 +174,7 @@ locale::__imp::__imp(size_t refs) : facet(refs), facets_(N), name_("C") {
   install(&make<codecvt<char16_t, char, mbstate_t> >(1u));
   install(&make<codecvt<char32_t, char, mbstate_t> >(1u));
   _LIBCPP_SUPPRESS_DEPRECATED_POP
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
+#if _LIBCPP_HAS_CHAR8_T
   install(&make<codecvt<char16_t, char8_t, mbstate_t> >(1u));
   install(&make<codecvt<char32_t, char8_t, mbstate_t> >(1u));
 #endif
@@ -219,9 +219,9 @@ locale::__imp::__imp(size_t refs) : facet(refs), facets_(N), name_("C") {
 }
 
 locale::__imp::__imp(const string& name, size_t refs) : facet(refs), facets_(N), name_(name) {
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
     facets_ = locale::classic().__locale_->facets_;
     for (unsigned i = 0; i < facets_.size(); ++i)
       if (facets_[i])
@@ -242,7 +242,7 @@ locale::__imp::__imp(const string& name, size_t refs) : facet(refs), facets_(N),
     install(new codecvt_byname<char16_t, char, mbstate_t>(name_));
     install(new codecvt_byname<char32_t, char, mbstate_t>(name_));
     _LIBCPP_SUPPRESS_DEPRECATED_POP
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
+#if _LIBCPP_HAS_CHAR8_T
     install(new codecvt_byname<char16_t, char8_t, mbstate_t>(name_));
     install(new codecvt_byname<char32_t, char8_t, mbstate_t>(name_));
 #endif
@@ -268,14 +268,14 @@ locale::__imp::__imp(const string& name, size_t refs) : facet(refs), facets_(N),
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
     install(new messages_byname<wchar_t>(name_));
 #endif
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   } catch (...) {
     for (unsigned i = 0; i < facets_.size(); ++i)
       if (facets_[i])
         facets_[i]->__release_shared();
     throw;
   }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
 }
 
 locale::__imp::__imp(const __imp& other) : facets_(max<size_t>(N, other.facets_.size())), name_(other.name_) {
@@ -291,9 +291,9 @@ locale::__imp::__imp(const __imp& other, const string& name, locale::category c)
   for (unsigned i = 0; i < facets_.size(); ++i)
     if (facets_[i])
       facets_[i]->__add_shared();
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
     if (c & locale::collate) {
       install(new collate_byname<char>(name));
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
@@ -313,7 +313,7 @@ locale::__imp::__imp(const __imp& other, const string& name, locale::category c)
       install(new codecvt_byname<char16_t, char, mbstate_t>(name));
       install(new codecvt_byname<char32_t, char, mbstate_t>(name));
       _LIBCPP_SUPPRESS_DEPRECATED_POP
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
+#if _LIBCPP_HAS_CHAR8_T
       install(new codecvt_byname<char16_t, char8_t, mbstate_t>(name));
       install(new codecvt_byname<char32_t, char8_t, mbstate_t>(name));
 #endif
@@ -348,14 +348,14 @@ locale::__imp::__imp(const __imp& other, const string& name, locale::category c)
       install(new messages_byname<wchar_t>(name));
 #endif
     }
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   } catch (...) {
     for (unsigned i = 0; i < facets_.size(); ++i)
       if (facets_[i])
         facets_[i]->__release_shared();
     throw;
   }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
 }
 
 template <class F>
@@ -370,9 +370,9 @@ locale::__imp::__imp(const __imp& other, const __imp& one, locale::category c)
   for (unsigned i = 0; i < facets_.size(); ++i)
     if (facets_[i])
       facets_[i]->__add_shared();
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
     if (c & locale::collate) {
       install_from<std::collate<char> >(one);
 #ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
@@ -389,7 +389,7 @@ locale::__imp::__imp(const __imp& other, const __imp& one, locale::category c)
       install_from<std::codecvt<char16_t, char, mbstate_t> >(one);
       install_from<std::codecvt<char32_t, char, mbstate_t> >(one);
       _LIBCPP_SUPPRESS_DEPRECATED_POP
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
+#if _LIBCPP_HAS_CHAR8_T
       install_from<std::codecvt<char16_t, char8_t, mbstate_t> >(one);
       install_from<std::codecvt<char32_t, char8_t, mbstate_t> >(one);
 #endif
@@ -443,14 +443,14 @@ locale::__imp::__imp(const __imp& other, const __imp& one, locale::category c)
       install_from<std::messages<wchar_t> >(one);
 #endif
     }
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   } catch (...) {
     for (unsigned i = 0; i < facets_.size(); ++i)
       if (facets_[i])
         facets_[i]->__release_shared();
     throw;
   }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
 }
 
 locale::__imp::__imp(const __imp& other, facet* f, long id)
@@ -2815,7 +2815,7 @@ int codecvt<char16_t, char, mbstate_t>::do_length(
 
 int codecvt<char16_t, char, mbstate_t>::do_max_length() const noexcept { return 4; }
 
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
+#if _LIBCPP_HAS_CHAR8_T
 
 // template <> class codecvt<char16_t, char8_t, mbstate_t>
 
@@ -2949,7 +2949,7 @@ int codecvt<char32_t, char, mbstate_t>::do_length(
 
 int codecvt<char32_t, char, mbstate_t>::do_max_length() const noexcept { return 4; }
 
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
+#if _LIBCPP_HAS_CHAR8_T
 
 // template <> class codecvt<char32_t, char8_t, mbstate_t>
 
@@ -5707,7 +5707,7 @@ template class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_
     codecvt_byname<char16_t, char, mbstate_t>;
 template class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
     codecvt_byname<char32_t, char, mbstate_t>;
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
+#if _LIBCPP_HAS_CHAR8_T
 template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char16_t, char8_t, mbstate_t>;
 template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char32_t, char8_t, mbstate_t>;
 #endif
diff --git a/libcxx/src/memory_resource.cpp b/libcxx/src/memory_resource.cpp
index d2ff350..299f810 100644
--- a/libcxx/src/memory_resource.cpp
+++ b/libcxx/src/memory_resource.cpp
@@ -9,7 +9,7 @@
 #include <memory>
 #include <memory_resource>
 
-#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
+#if _LIBCPP_HAS_ATOMIC_HEADER
 #  include <atomic>
 #elif !defined(_LIBCPP_HAS_NO_THREADS)
 #  include <mutex>
@@ -28,7 +28,7 @@ memory_resource::~memory_resource() = default;
 
 // new_delete_resource()
 
-#ifdef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+#if !_LIBCPP_HAS_ALIGNED_ALLOCATION
 static bool is_aligned_to(void* ptr, size_t align) {
   void* p2     = ptr;
   size_t space = 1;
@@ -39,7 +39,7 @@ static bool is_aligned_to(void* ptr, size_t align) {
 
 class _LIBCPP_EXPORTED_FROM_ABI __new_delete_memory_resource_imp : public memory_resource {
   void* do_allocate(size_t bytes, size_t align) override {
-#ifndef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+#if _LIBCPP_HAS_ALIGNED_ALLOCATION
     return std::__libcpp_allocate(bytes, align);
 #else
     if (bytes == 0)
@@ -91,7 +91,7 @@ memory_resource* null_memory_resource() noexcept { return &res_init.resources.nu
 // default_memory_resource()
 
 static memory_resource* __default_memory_resource(bool set = false, memory_resource* new_res = nullptr) noexcept {
-#ifndef _LIBCPP_HAS_NO_ATOMIC_HEADER
+#if _LIBCPP_HAS_ATOMIC_HEADER
   static constinit atomic<memory_resource*> __res{&res_init.resources.new_delete_res};
   if (set) {
     new_res = new_res ? new_res : new_delete_resource();
diff --git a/libcxx/src/mutex_destructor.cpp b/libcxx/src/mutex_destructor.cpp
index a6ceaaa..9f99172 100644
--- a/libcxx/src/mutex_destructor.cpp
+++ b/libcxx/src/mutex_destructor.cpp
@@ -19,7 +19,7 @@
 #include <__config>
 #include <__thread/support.h>
 
-#if _LIBCPP_ABI_VERSION == 1 || !defined(_LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION)
+#if _LIBCPP_ABI_VERSION == 1 || !_LIBCPP_HAS_TRIVIAL_MUTEX_DESTRUCTION
 #  define NEEDS_MUTEX_DESTRUCTOR
 #endif
 
diff --git a/libcxx/src/new.cpp b/libcxx/src/new.cpp
index b0c7316..e010fe4 100644
--- a/libcxx/src/new.cpp
+++ b/libcxx/src/new.cpp
@@ -51,7 +51,7 @@ _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)),
@@ -79,7 +79,7 @@ _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[])),
@@ -114,7 +114,7 @@ _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)
@@ -145,7 +145,7 @@ 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)),
@@ -174,7 +174,7 @@ 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[])),
@@ -220,7 +220,7 @@ _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 ------------------
 
 #endif // !__GLIBCXX__ && !_LIBCPP_ABI_VCRUNTIME
diff --git a/libcxx/src/new_helpers.cpp b/libcxx/src/new_helpers.cpp
index 6560d01..2119d82 100644
--- a/libcxx/src/new_helpers.cpp
+++ b/libcxx/src/new_helpers.cpp
@@ -18,7 +18,7 @@ const nothrow_t nothrow{};
 #ifndef LIBSTDCXX
 
 void __throw_bad_alloc() {
-#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#  if _LIBCPP_HAS_EXCEPTIONS
   throw bad_alloc();
 #  else
   _LIBCPP_VERBOSE_ABORT("bad_alloc was thrown in -fno-exceptions mode");
diff --git a/libcxx/src/ostream.cpp b/libcxx/src/ostream.cpp
index e1a9a4b..f036aaf 100644
--- a/libcxx/src/ostream.cpp
+++ b/libcxx/src/ostream.cpp
@@ -24,7 +24,7 @@ _LIBCPP_EXPORTED_FROM_ABI FILE* __get_ostream_file(ostream& __os) {
   // Returning a nullptr means the stream is not considered a terminal and the
   // special terminal handling is not done. The terminal handling is mainly of
   // importance on Windows.
-#ifndef _LIBCPP_HAS_NO_RTTI
+#if _LIBCPP_HAS_RTTI
   auto* __rdbuf = __os.rdbuf();
 #  ifndef _LIBCPP_HAS_NO_FILESYSTEM
   if (auto* __buffer = dynamic_cast<filebuf*>(__rdbuf))
@@ -33,7 +33,7 @@ _LIBCPP_EXPORTED_FROM_ABI FILE* __get_ostream_file(ostream& __os) {
 
   if (auto* __buffer = dynamic_cast<__stdoutbuf<char>*>(__rdbuf))
     return __buffer->__file_;
-#endif // _LIBCPP_HAS_NO_RTTI
+#endif // _LIBCPP_HAS_RTTI
 
   return nullptr;
 }
diff --git a/libcxx/src/ryu/d2s.cpp b/libcxx/src/ryu/d2s.cpp
index 32d617c..5b80ed8 100644
--- a/libcxx/src/ryu/d2s.cpp
+++ b/libcxx/src/ryu/d2s.cpp
@@ -478,7 +478,7 @@ struct __floating_decimal_64 {
           36893488u, 7378697u, 1475739u, 295147u, 59029u, 11805u, 2361u, 472u, 94u, 18u, 3u };
 
         unsigned long _Trailing_zero_bits;
-#ifdef _LIBCPP_HAS_BITSCAN64
+#if _LIBCPP_HAS_BITSCAN64
         (void) _BitScanForward64(&_Trailing_zero_bits, __v.__mantissa); // __v.__mantissa is guaranteed nonzero
 #else // ^^^ 64-bit ^^^ / vvv 32-bit vvv
         const uint32_t _Low_mantissa = static_cast<uint32_t>(__v.__mantissa);
diff --git a/libcxx/src/stdexcept.cpp b/libcxx/src/stdexcept.cpp
index 134d28e..0ee438b 100644
--- a/libcxx/src/stdexcept.cpp
+++ b/libcxx/src/stdexcept.cpp
@@ -20,7 +20,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 void __throw_runtime_error(const char* msg) {
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   throw runtime_error(msg);
 #else
   _LIBCPP_VERBOSE_ABORT("runtime_error was thrown in -fno-exceptions mode with message \"%s\"", msg);
diff --git a/libcxx/src/support/runtime/exception_fallback.ipp b/libcxx/src/support/runtime/exception_fallback.ipp
index bedb16e..ba283ae 100644
--- a/libcxx/src/support/runtime/exception_fallback.ipp
+++ b/libcxx/src/support/runtime/exception_fallback.ipp
@@ -34,18 +34,18 @@ terminate_handler set_terminate(terminate_handler func) noexcept {
 terminate_handler get_terminate() noexcept { return __libcpp_atomic_load(&__terminate_handler); }
 
 [[noreturn]] void terminate() noexcept {
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
     (*get_terminate())();
     // handler should not return
     __libcpp_verbose_abort("terminate_handler unexpectedly returned\n");
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   } catch (...) {
     // handler should not throw exception
     __libcpp_verbose_abort("terminate_handler unexpectedly threw an exception\n");
   }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
 }
 
 bool uncaught_exception() noexcept { return uncaught_exceptions() > 0; }
diff --git a/libcxx/src/support/runtime/exception_msvc.ipp b/libcxx/src/support/runtime/exception_msvc.ipp
index 869b64d..2ae004b 100644
--- a/libcxx/src/support/runtime/exception_msvc.ipp
+++ b/libcxx/src/support/runtime/exception_msvc.ipp
@@ -42,18 +42,18 @@ terminate_handler set_terminate(terminate_handler func) noexcept { return ::set_
 terminate_handler get_terminate() noexcept { return ::_get_terminate(); }
 
 [[noreturn]] void terminate() noexcept {
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   try {
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
     (*get_terminate())();
     // handler should not return
     __libcpp_verbose_abort("terminate_handler unexpectedly returned\n");
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   } catch (...) {
     // handler should not throw exception
     __libcpp_verbose_abort("terminate_handler unexpectedly threw an exception\n");
   }
-#endif // _LIBCPP_HAS_NO_EXCEPTIONS
+#endif // _LIBCPP_HAS_EXCEPTIONS
 }
 
 bool uncaught_exception() noexcept { return uncaught_exceptions() > 0; }
diff --git a/libcxx/src/system_error.cpp b/libcxx/src/system_error.cpp
index 3367bd5..4767293 100644
--- a/libcxx/src/system_error.cpp
+++ b/libcxx/src/system_error.cpp
@@ -211,7 +211,7 @@ system_error::system_error(int ev, const error_category& ecat)
 system_error::~system_error() noexcept {}
 
 void __throw_system_error(int ev, const char* what_arg) {
-#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
+#if _LIBCPP_HAS_EXCEPTIONS
   std::__throw_system_error(error_code(ev, system_category()), what_arg);
 #else
   // The above could also handle the no-exception case, but for size, avoid referencing system_category() unnecessarily.