[libc++][hardening] Implement support for assertion semantics.

[var-const]

No description provided.

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff HEAD~1 HEAD --extensions ,h,cpp -- libcxx/include/__log_hardening_failure libcxx/include/__verbose_trap libcxx/src/log_hardening_failure.cpp libcxxabi/src/log_error_and_continue.cpp libcxxabi/src/log_error_and_continue.h libcxx/include/__config libcxx/include/__configuration/availability.h libcxx/test/support/check_assertion.h libcxxabi/src/demangle/DemangleConfig.h

View the diff from clang-format here.

diff --git a/libcxx/include/__config b/libcxx/include/__config
index c6e90d3a5..2223d466c 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -519,7 +519,7 @@ typedef __char32_t char32_t;
 #  ifndef _LIBCPP_NO_ABI_TAG
 #    define _LIBCPP_HIDE_FROM_ABI                                                                                      \
       _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION                                                       \
-          __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_ODR_SIGNATURE))))
+      __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_ODR_SIGNATURE))))
 #  else
 #    define _LIBCPP_HIDE_FROM_ABI _LIBCPP_HIDDEN _LIBCPP_EXCLUDE_FROM_EXPLICIT_INSTANTIATION
 #  endif
diff --git a/libcxx/include/__verbose_trap b/libcxx/include/__verbose_trap
index db77b29e6..13ea72773 100644
--- a/libcxx/include/__verbose_trap
+++ b/libcxx/include/__verbose_trap
@@ -18,19 +18,18 @@
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
-#  if __has_builtin(__builtin_verbose_trap)
+#if __has_builtin(__builtin_verbose_trap)
 // AppleClang shipped a slightly different version of __builtin_verbose_trap from the upstream
 // version before upstream Clang actually got the builtin.
 // TODO: Remove once AppleClang supports the two-arguments version of the builtin.
-#    if defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1700
-#      define _LIBCPP_VERBOSE_TRAP(message) __builtin_verbose_trap(message)
-#    else
-#      define _LIBCPP_VERBOSE_TRAP(message) __builtin_verbose_trap("libc++", message)
-#    endif
+#  if defined(_LIBCPP_APPLE_CLANG_VER) && _LIBCPP_APPLE_CLANG_VER < 1700
+#    define _LIBCPP_VERBOSE_TRAP(message) __builtin_verbose_trap(message)
 #  else
-#    define _LIBCPP_VERBOSE_TRAP(message) ((void)message, __builtin_trap())
+#    define _LIBCPP_VERBOSE_TRAP(message) __builtin_verbose_trap("libc++", message)
 #  endif
-
+#else
+#  define _LIBCPP_VERBOSE_TRAP(message) ((void)message, __builtin_trap())
+#endif
 
 _LIBCPP_END_NAMESPACE_STD
 
diff --git a/libcxxabi/src/log_error_and_continue.cpp b/libcxxabi/src/log_error_and_continue.cpp
index 51088cd11..51cee6d56 100644
--- a/libcxxabi/src/log_error_and_continue.cpp
+++ b/libcxxabi/src/log_error_and_continue.cpp
@@ -18,11 +18,10 @@ extern "C" void android_set_abort_message(const char* msg);
 
 #if defined(__APPLE__) && __has_include(<os/reason_private.h>)
 #  include <os/reason_private.h>
-#   define _LIBCXXABI_USE_OS_FAULT
+#  define _LIBCXXABI_USE_OS_FAULT
 #endif
 
-void __log_error_and_continue(const char* message)
-{
+void __log_error_and_continue(const char* message) {
   // On Apple platforms, use the `os_fault_with_payload` OS function that simulates a crash.
 #if defined(_LIBCXXABI_USE_OS_FAULT)
   os_fault_with_payload(

[ldionne]

I think that is incorrect. We do evaluate the assertion, but then we do nothing with that. Let's make this documentation accurate.

That being said, let's also file a Github issue to later go back and fix this: we should mirror what the actual C++26 contracts do, and not evaluate the assertion. Since that's going to require a rework of our assertion machinery, let's not do that right now.