Implement uncaught_exceptions() using the newly added hooks in libc++abi, when available

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@238846 91177308-0d34-0410-b5e6-96231b3b80d8

include/exception

@@ -48,7 +48,8 @@ terminate_handler set_terminate(terminate_handler  f ) noexcept;
 terminate_handler get_terminate() noexcept;
 [[noreturn]] void terminate() noexcept;
 
-bool uncaught_exception() noexcept;
+bool uncaught_exception()  noexcept;
+int  uncaught_exceptions() noexcept;  // C++17
 
 typedef unspecified exception_ptr;
 
@@ -115,6 +116,7 @@ _LIBCPP_FUNC_VIS terminate_handler get_terminate() _NOEXCEPT;
 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void terminate() _NOEXCEPT;
 
 _LIBCPP_FUNC_VIS bool uncaught_exception() _NOEXCEPT;
+_LIBCPP_FUNC_VIS int uncaught_exceptions() _NOEXCEPT;
 
 class _LIBCPP_TYPE_VIS exception_ptr;
 

src/exception.cpp

@@ -105,19 +105,25 @@ terminate() _NOEXCEPT
 #endif // !__EMSCRIPTEN__
 #endif // !defined(LIBCXXRT) && !defined(_LIBCPPABI_VERSION)
 
+bool uncaught_exception() _NOEXCEPT { return uncaught_exceptions() > 0; }
+
 #if !defined(LIBCXXRT) && !defined(__GLIBCXX__) && !defined(__EMSCRIPTEN__)
-bool uncaught_exception() _NOEXCEPT
+int uncaught_exceptions() _NOEXCEPT
 {
 #if defined(__APPLE__) || defined(_LIBCPPABI_VERSION)
-    // on Darwin, there is a helper function so __cxa_get_globals is private
+   // on Darwin, there is a helper function so __cxa_get_globals is private
-    return __cxa_uncaught_exception();
+# if _LIBCPPABI_VERSION > 1101
+    return __cxa_uncaught_exceptions();
+# else
+    return __cxa_uncaught_exception() ? 1 : 0;
+# endif
 #else  // __APPLE__
 #   if defined(_MSC_VER) && ! defined(__clang__)
-        _LIBCPP_WARNING("uncaught_exception not yet implemented")
+        _LIBCPP_WARNING("uncaught_exceptions not yet implemented")
 #   else
 #       warning uncaught_exception not yet implemented
 #   endif
-    fprintf(stderr, "uncaught_exception not yet implemented\n");
+    fprintf(stderr, "uncaught_exceptions not yet implemented\n");
     ::abort();
 #endif  // __APPLE__
 }

test/std/language.support/support.exception/uncaught/uncaught_exceptions.pass.cpp

@@ -0,0 +1,45 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// test uncaught_exceptions
+
+#include <exception>
+#include <cassert>
+
+struct A
+{
+    ~A()
+    {
+        assert(std::uncaught_exceptions() > 0);
+    }
+};
+
+struct B
+{
+    B()
+    {
+        // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#475
+        assert(std::uncaught_exceptions() == 0);
+    }
+};
+
+int main()
+{
+    try
+    {
+        A a;
+        assert(std::uncaught_exceptions() == 0);
+        throw B();
+    }
+    catch (...)
+    {
+        assert(std::uncaught_exception() == 0);
+    }
+    assert(std::uncaught_exceptions() == 0);
+}

www/cxx1z_status.html

@@ -57,7 +57,7 @@
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4169">N4169</a></td><td>LWG</td></td><td>A proposal to add invoke function template</td><td>Urbana</td><td></td><td></td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4190">N4190</a></td></td><td>LWG</td><td>Removing auto_ptr, random_shuffle(), And Old <functional> Stuff.</td><td>Urbana</td><td></td><td></td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4258">N4258</a></td><td>LWG</td></td><td>Cleaning-up noexcept in the Library.</td><td>Urbana</td><td></td><td></td></tr>
-	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4259">N4259</a></td><td>CWG</td></td><td>Wording for std::uncaught_exceptions</td><td>Urbana</td><td></td><td></td></tr>
+	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4259">N4259</a></td><td>CWG</td></td><td>Wording for std::uncaught_exceptions</td><td>Urbana</td><td>Complete</td><td>3.7</td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4277">N4277</a></td><td>LWG</td></td><td>TriviallyCopyable <code>reference_wrapper</code>.</td><td>Urbana</td><td>Complete</td><td>3.2</td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4279">N4279</a></td><td>LWG</td></td><td>Improved insertion interface for unique-key maps.</td><td>Urbana</td><td></td><td></td></tr>
 	<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4280">N4280</a></td><td>LWG</td></td><td>Non-member size() and more</td><td>Urbana</td><td>Complete</td><td>3.6</td></tr>