PR libstdc++/51333 Define recursive_init_error constructor non-inline

The recursive_init_error class is defined in a header, with an inline
constructor, but the definition of the vtable and destructor are not
exported from the shared library. With -fkeep-inline-functions the
constructor gets emitted in user code, and requires the (non-exported)
vtable. This fails to link.

As far as I can tell, the recursive_init_error class definition was
moved into <cxxabi.h> so it could be documented with Doxygen, not for
any technical reason. But now it's there (and documented), somebody
could be relying on it, by catching that type and possibly performing
derived-to-base conversions to the std::exception base class. So the
conservative fix is to leave the class definition in the header but make
the constructor non-inline. This still allows the type to be caught and
still defines its base class. User code can no longer construct objects
of that type, but that's not something we need to support.

	PR libstdc++/51333
	* libsupc++/cxxabi.h (__gnu_cxx::recursive_init_error): Do not define
	constructor inline.
	* libsupc++/guard_error.cc (__gnu_cxx::recursive_init_error): Define
	constructor.
	* testsuite/18_support/51333.cc: New test.

From-SVN: r273878

libstdc++-v3/ChangeLog

+2019-07-29  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/51333
+	* libsupc++/cxxabi.h (__gnu_cxx::recursive_init_error): Do not define
+	constructor inline.
+	* libsupc++/guard_error.cc (__gnu_cxx::recursive_init_error): Define
+	constructor.
+	* testsuite/18_support/51333.cc: New test.
+
 2019-07-28  Gerald Pfeifer  <gerald@pfeifer.com>
 
 	* doc/xml/manual/documentation_hacking.xml: Fix broken reference

libstdc++-v3/libsupc++/cxxabi.h

@@ -684,8 +684,9 @@ namespace __gnu_cxx
    *  @brief Exception thrown by __cxa_guard_acquire.
    *  @ingroup exceptions
    *
-   *  6.7[stmt.dcl]/4: If control re-enters the declaration (recursively)
-   *  while the object is being initialized, the behavior is undefined.
+   *  C++ 2011 6.7 [stmt.dcl]/4: If control re-enters the declaration
+   *  recursively while the variable is being initialized, the behavior
+   *  is undefined.
    *
    *  Since we already have a library function to handle locking, we might
    *  as well check for this situation and throw an exception.
@@ -695,8 +696,8 @@ namespace __gnu_cxx
   class recursive_init_error: public std::exception
   {
   public:
-    recursive_init_error() throw() { }
-    virtual ~recursive_init_error() throw ();
+    recursive_init_error() _GLIBCXX_NOTHROW;
+    virtual ~recursive_init_error() _GLIBCXX_NOTHROW;
   };
 }
 #endif // __cplusplus

libstdc++-v3/libsupc++/guard_error.cc

@@ -26,6 +26,6 @@
 
 namespace __gnu_cxx
 {
-  recursive_init_error::~recursive_init_error() throw() { }
+  recursive_init_error::recursive_init_error() noexcept { }
+  recursive_init_error::~recursive_init_error() noexcept { }
 }
-

libstdc++-v3/testsuite/18_support/51333.cc

+// Copyright (C) 2019 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-fkeep-inline-functions" }
+// { dg-do link }
+
+#include <cxxabi.h>
+int main() { } // PR libstdc++/51333