Add libc++ and libc++abi to third-party.

third_party/libc++abi/src/cxa_handlers.cpp

+//===------------------------- cxa_handlers.cpp ---------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//
+// This file implements the functionality associated with the terminate_handler,
+//   unexpected_handler, and new_handler.
+//===----------------------------------------------------------------------===//
+
+#include <stdexcept>
+#include <new>
+#include <exception>
+#include "abort_message.h"
+#include "cxxabi.h"
+#include "cxa_handlers.hpp"
+#include "cxa_exception.hpp"
+#include "private_typeinfo.h"
+
+namespace std
+{
+
+unexpected_handler
+get_unexpected() _NOEXCEPT
+{
+    return __sync_fetch_and_add(&__cxa_unexpected_handler, (unexpected_handler)0);
+//  The above is safe but overkill on x86
+//  Using of C++11 atomics this should be rewritten
+//  return __cxa_unexpected_handler.load(memory_order_acq);
+}
+
+__attribute__((visibility("hidden"), noreturn))
+void
+__unexpected(unexpected_handler func)
+{
+    func();
+    // unexpected handler should not return
+    abort_message("unexpected_handler unexpectedly returned");
+}
+
+__attribute__((noreturn))
+void
+unexpected()
+{
+    __unexpected(get_unexpected());
+}
+
+terminate_handler
+get_terminate() _NOEXCEPT
+{
+    return __sync_fetch_and_add(&__cxa_terminate_handler, (terminate_handler)0);
+//  The above is safe but overkill on x86
+//  Using of C++11 atomics this should be rewritten
+//  return __cxa_terminate_handler.load(memory_order_acq);
+}
+
+__attribute__((visibility("hidden"), noreturn))
+void
+__terminate(terminate_handler func) _NOEXCEPT
+{
+#if __has_feature(cxx_exceptions)
+    try
+    {
+#endif  // __has_feature(cxx_exceptions)
+        func();
+        // handler should not return
+        abort_message("terminate_handler unexpectedly returned");
+#if __has_feature(cxx_exceptions)
+    }
+    catch (...)
+    {
+        // handler should not throw exception
+        abort_message("terminate_handler unexpectedly threw an exception");
+    }
+#endif  // #if __has_feature(cxx_exceptions)
+}
+
+__attribute__((noreturn))
+void
+terminate() _NOEXCEPT
+{
+    // If there might be an uncaught exception
+    using namespace __cxxabiv1;
+    __cxa_eh_globals* globals = __cxa_get_globals_fast();
+    if (globals)
+    {
+        __cxa_exception* exception_header = globals->caughtExceptions;
+        if (exception_header)
+        {
+            _Unwind_Exception* unwind_exception =
+                reinterpret_cast<_Unwind_Exception*>(exception_header + 1) - 1;
+            bool native_exception =
+                (unwind_exception->exception_class & get_vendor_and_language) ==
+                               (kOurExceptionClass & get_vendor_and_language);
+            if (native_exception)
+                __terminate(exception_header->terminateHandler);
+        }
+    }
+    __terminate(get_terminate());
+}
+
+extern "C" new_handler __cxa_new_handler = 0;
+// In the future these will become:
+// std::atomic<std::new_handler>  __cxa_new_handler(0);
+
+new_handler
+set_new_handler(new_handler handler) _NOEXCEPT
+{
+    return __sync_swap(&__cxa_new_handler, handler);
+//  Using of C++11 atomics this should be rewritten
+//  return __cxa_new_handler.exchange(handler, memory_order_acq_rel);
+}
+
+new_handler
+get_new_handler() _NOEXCEPT
+{
+    return __sync_fetch_and_add(&__cxa_new_handler, (new_handler)0);
+//  The above is safe but overkill on x86
+//  Using of C++11 atomics this should be rewritten
+//  return __cxa_new_handler.load(memory_order_acq);
+}
+
+}  // std