PR libstdc++/53984 handle exceptions in basic_istream::sentry

	PR libstdc++/53984
	* include/bits/basic_ios.h (basic_ios::_M_setstate): Adjust comment.
	* include/bits/istream.tcc (basic_istream::sentry): Handle exceptions
	during construction.
	* include/std/istream: Adjust comments for formatted input functions
	and unformatted input functions.
	* testsuite/27_io/basic_fstream/53984.cc: New.
	* testsuite/27_io/basic_istream/sentry/char/53984.cc: New.

From-SVN: r250545

libstdc++-v3/ChangeLog

 2017-07-25  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/53984
+	* include/bits/basic_ios.h (basic_ios::_M_setstate): Adjust comment.
+	* include/bits/istream.tcc (basic_istream::sentry): Handle exceptions
+	during construction.
+	* include/std/istream: Adjust comments for formatted input functions
+	and unformatted input functions.
+	* testsuite/27_io/basic_fstream/53984.cc: New.
+	* testsuite/27_io/basic_istream/sentry/char/53984.cc: New.
+
 	* include/bits/ios_base.h (ios_base::io_state, ios_base::open_mode)
 	(ios_base::seek_dir): Remove for C++17.
 	* include/std/streambuf (basic_streambuf::stossc): Remove for C++17.

libstdc++-v3/include/bits/basic_ios.h

@@ -157,8 +157,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       setstate(iostate __state)
       { this->clear(this->rdstate() | __state); }
 
-      // Flip the internal state on for the proper state bits, then re
-      // throws the propagated exception if bit also set in
+      // Flip the internal state on for the proper state bits, then
+      // rethrows the propagated exception if bit also set in
       // exceptions().
       void
       _M_setstate(iostate __state)

libstdc++-v3/include/bits/istream.tcc

@@ -48,28 +48,36 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
       ios_base::iostate __err = ios_base::goodbit;
       if (__in.good())
-	{
-	  if (__in.tie())
-	    __in.tie()->flush();
-	  if (!__noskip && bool(__in.flags() & ios_base::skipws))
-	    {
-	      const __int_type __eof = traits_type::eof();
-	      __streambuf_type* __sb = __in.rdbuf();
-	      __int_type __c = __sb->sgetc();
-
-	      const __ctype_type& __ct = __check_facet(__in._M_ctype);
-	      while (!traits_type::eq_int_type(__c, __eof)
-		     && __ct.is(ctype_base::space, 
-				traits_type::to_char_type(__c)))
-		__c = __sb->snextc();
+	__try
+	  {
+	    if (__in.tie())
+	      __in.tie()->flush();
+	    if (!__noskip && bool(__in.flags() & ios_base::skipws))
+	      {
+		const __int_type __eof = traits_type::eof();
+		__streambuf_type* __sb = __in.rdbuf();
+		__int_type __c = __sb->sgetc();
+
+		const __ctype_type& __ct = __check_facet(__in._M_ctype);
+		while (!traits_type::eq_int_type(__c, __eof)
+		       && __ct.is(ctype_base::space,
+				  traits_type::to_char_type(__c)))
+		  __c = __sb->snextc();
 
-	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
-	      // 195. Should basic_istream::sentry's constructor ever
-	      // set eofbit?
-	      if (traits_type::eq_int_type(__c, __eof))
-		__err |= ios_base::eofbit;
-	    }
-	}
+		// _GLIBCXX_RESOLVE_LIB_DEFECTS
+		// 195. Should basic_istream::sentry's constructor ever
+		// set eofbit?
+		if (traits_type::eq_int_type(__c, __eof))
+		  __err |= ios_base::eofbit;
+	      }
+	  }
+	__catch(__cxxabiv1::__forced_unwind&)
+	  {
+	    __in._M_setstate(ios_base::badbit);
+	    __throw_exception_again;
+	  }
+	__catch(...)
+	  { __in._M_setstate(ios_base::badbit); }
 
       if (__in.good() && __err == ios_base::goodbit)
 	_M_ok = true;

libstdc++-v3/include/std/istream

@@ -150,9 +150,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *  whatever data is appropriate for the type of the argument.
        *
        *  If an exception is thrown during extraction, ios_base::badbit
-       *  will be turned on in the stream's error state without causing an
-       *  ios_base::failure to be thrown.  The original exception will then
-       *  be rethrown.
+       *  will be turned on in the stream's error state (without causing an
+       *  ios_base::failure to be thrown) and the original exception will
+       *  be rethrown if badbit is set in the exceptions mask.
       */
 
       //@{
@@ -286,9 +286,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        *  by gcount().
        *
        *  If an exception is thrown during extraction, ios_base::badbit
-       *  will be turned on in the stream's error state without causing an
-       *  ios_base::failure to be thrown.  The original exception will then
-       *  be rethrown.
+       *  will be turned on in the stream's error state (without causing an
+       *  ios_base::failure to be thrown) and the original exception will
+       *  be rethrown if badbit is set in the exceptions mask.
       */
 
       /**

libstdc++-v3/testsuite/27_io/basic_fstream/53984.cc

+// Copyright (C) 2017 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-require-file-io "" }
+
+#include <fstream>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  std::fstream in(".");
+  int x;
+  in >> x;
+  VERIFY( in.bad() );
+}
+
+int
+main()
+{
+  test01();
+}

libstdc++-v3/testsuite/27_io/basic_istream/sentry/char/53984.cc

+// Copyright (C) 2017 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/>.
+
+#include <streambuf>
+#include <istream>
+#include <testsuite_hooks.h>
+
+struct SB : std::streambuf
+{
+  virtual int_type underflow() { throw 1; }
+};
+
+void
+test01()
+{
+  SB sb;
+  std::istream is(&sb);
+  int i;
+  is >> i;
+  VERIFY( is.bad() );
+}
+
+int
+main()
+{
+  test01();
+}