[Bug libstdc++/69191] New: Wrong equality comparison between error_code and error_condition + segfault

[eyenseo at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69191

            Bug ID: 69191
           Summary: Wrong equality comparison between error_code and
                    error_condition + segfault
           Product: gcc
           Version: 4.9.3
            Status: UNCONFIRMED
          Severity: critical
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: eyenseo at gmail dot com
  Target Milestone: ---

Created attachment 37264
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37264&action=edit
Precompiled minimal testcase

Greetings!

This is a bug (maybe two) regarding the comparison of std::error_condition and
std::error_code. An error_code and an error_condition with same value, message
and category name are not identified as same - but they should.

While pinpointing this bug I happened to produce a segmentation fault in
libstdc++ that is most probably part of the comparison bug. Using Clang with
libstdc++ produces the same result (including segfault). Using Clang with
libc++ produces the expected results and there is no segfault.


command line:
g++ --std=c++11 main.cpp && ./a.out

output:
code == con1: 0
code == con2: 1
con1 == con2: 0
con1 == con3: 0
con2 == con3: 0

code: value: 13
  message: Permission denied
  category name: generic
con1: value: 13
  message: Permission denied
  category name: generic
con2: value: 13
  message: Permission denied
  category name: generic
con3: value: 0
  message: Success
  category name: generic

expected:
code == con1: 1
code == con2: 1
con1 == con2: 1
con1 == con3: 1
con2 == con3: 1

code:   value: 13
        message: Permission denied
        category name: generic
con1:   value: 13
        message: Permission denied
        category name: generic
con2:   value: 13
        message: Permission denied
        category name: generic
con3:   value: 13
        message: Permission denied
        category name: generic


Source: main.cpp
#include <system_error>
#include <iostream>

#define equals(a, b) std::cout << #a " == " #b ": " << (a == b) << '\n';
#define print(a)                                                              \
  std::cout << #a ":\tvalue: " << a.value() << "\n\tmessage: " << a.message() \
            << "\n\tcategory name: " << a.category().name() << '\n';

int main(int, char const* []) {
  auto code = std::make_error_code(std::errc::permission_denied);
  auto con1 = std::make_error_condition(std::errc::permission_denied);
  auto con2 = code.category().default_error_condition(code.value());
  auto con3 = code.default_error_condition();

  equals(code, con1);  // This should be true
  equals(code, con2);  // This is true
  // equals(code, con3);  // Segmentation fault
  //                      // std::_V2::error_category::equivalent(int,
  //                      // std::error_condition const&) const () from
  //                      // /usr/lib/x86_64-linux-gnu/libstdc++.so.6
  equals(con1, con2);  // This should be true
  equals(con1, con3);  // This should be true
  equals(con2, con3);  // This should be true

  std::cout << '\n';

  print(code);  // Same as con1 and con2
  print(con1);  // Same as code and con2
  print(con2);  // Same as code and con1
  print(con3);  // This should be the same as code and con1 and con2

  return 0;
}


My system is:
x86_64-linux-gnu

GCC build:
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
4.9.3-8ubuntu2~14.04' --with-bugurl=file:///usr/share/doc/gcc-4.9/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.9 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.9 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-vtable-verify
--enable-plugin --with-system-zlib --disable-browser-plugin
--enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.9-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.9-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --disable-werror --with-arch-32=i686
--with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib
--with-tune=generic --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu