[Bug libstdc++/66145] New: std::ios_base::failure objects thrown from libstdc++.so use old ABI

[Bug libstdc++/66145] New: std::ios_base::failure objects thrown from libstdc++.so use old ABI

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145

            Bug ID: 66145
           Summary: std::ios_base::failure objects thrown from
                    libstdc++.so use old ABI
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Keywords: ABI
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
                CC: doko at gcc dot gnu.org
  Target Milestone: ---

Using the new cxx11 ABI in GCC5 (and trunk) the exception here isn't caught:

#define _GLIBCXX_USE_CXX11_ABI 1
#include <fstream>
#include <limits>

int main()
{
  std::fstream f;
  f.exceptions(std::ios::badbit);
  try {
    f.pword(std::numeric_limits<int>::max());
  } catch (const std::ios_base::failure&) {
    return 0;
  }
  throw 1;
}


terminate called after throwing an instance of 'std::ios_base::failure'
  what():  ios_base::_M_grow_words is not valid
Aborted (core dumped)

This is because src/c++11/functexcept.cc has:

// We don't want to change the type thrown by __throw_ios_failure (yet?)
#define _GLIBCXX_USE_CXX11_ABI 0

I actually planned to change it for GCC5 but missed it. If we change the ABI
used to compile functexcept.cc then the code above would fail when using the
old ABI instead.

One option to make both forms work would be to hack the EH runtime to make
handlers for std::ios_base::failure able to catch
std::ios_base::failure[abi:cxx11] objects, and vice versa, creating an object
of the other type on the fly.

[Bug libstdc++/66145] [5/6 Regression] std::ios_base::failure objects thrown from libstdc++.so use old ABI

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-05-20
      Known to work|                            |4.8.4, 4.9.2
            Summary|std::ios_base::failure      |[5/6 Regression]
                   |objects thrown from         |std::ios_base::failure
                   |libstdc++.so use old ABI    |objects thrown from
                   |                            |libstdc++.so use old ABI
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Let's call this a regression, since the testcase used to catch the exception,
but now doesn't with the default build settings.

[Bug libstdc++/66145] [5/6 Regression] std::ios_base::failure objects thrown from libstdc++.so use old ABI

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |costamagnagianfranco@yahoo.
                   |                            |it

--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
*** Bug 66262 has been marked as a duplicate of this bug. ***

[Bug libstdc++/66145] [5/6 Regression] std::ios_base::failure objects thrown from libstdc++.so use old ABI

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
           Priority|P3                          |P2
   Target Milestone|---                         |5.3

[Bug libstdc++/66145] [5/6 Regression] std::ios_base::failure objects thrown from libstdc++.so use old ABI

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Reduced from testcase at  https://bugzilla.redhat.com/show_bug.cgi?id=1269290

#include <iostream>
#include <fstream>
#include <system_error>
#include <exception>


int main() {

  try {
    std::ifstream input("notafile");
    input.exceptions(std::ifstream::failbit | std::ifstream::badbit);
    input.get();
  } catch(const std::ios::failure &e) {
    std::cout << "caught a failure " << e.what()
      << '\n';
  } catch(const std::system_error &e) {
    std::cout << "caught a system_error " << e.what()
      << '\n';
  } catch(const std::runtime_error &e) {
    std::cout << "caught a runtime_error " << e.what()
      << '\n';
  } catch(const std::exception &e) {
    std::cout << "caught an exception " << e.what()
      << '\n';
  }
}

The last handler matches, but it should have matched earlier.

[Bug libstdc++/66145] [5/6 Regression] std::ios_base::failure objects thrown from libstdc++.so use old ABI

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #4)
> The last handler matches, but it should have matched earlier.

Doh, this is expected, because the C++03 ios::failure doesn't derive from
runtime_error.