Re: [PATCH 1/3] libstdc++: Improve output of default contract violation handler [PR107792]

[Jonathan Wakely <jwakely.gcc@gmail.com>]

On Thu, 22 Dec 2022 at 21:41, Jason Merrill via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> On 12/22/22 06:03, Arsen Arsenović wrote:
> > From: Jonathan Wakely <jwakely@redhat.com>
> >
> > Make the output more readable. Don't output anything unless verbose
> > termination is enabled at configure-time.
>
> LGTM if Jonathan agrees.  The testsuite changes should be applied in the
> same commit.

Yup, Arsen and I have been discussing this patch over IRC, I'm happy with it.

>
> > libstdc++-v3/ChangeLog:
> >
> >       PR libstdc++/107792
> >       PR libstdc++/107778
> >       * src/experimental/contract.cc (handle_contract_violation): Make
> >       output more readable.
> > ---
> > Heh, wouldn't be me if I forgot nothing.  Sorry about that.
> >
> > How's this?
> >
> >   libstdc++-v3/src/experimental/contract.cc | 50 ++++++++++++++++++-----
> >   1 file changed, 39 insertions(+), 11 deletions(-)
> >
> > diff --git a/libstdc++-v3/src/experimental/contract.cc b/libstdc++-v3/src/experimental/contract.cc
> > index c8d2697eddc..2d41a6326cf 100644
> > --- a/libstdc++-v3/src/experimental/contract.cc
> > +++ b/libstdc++-v3/src/experimental/contract.cc
> > @@ -1,4 +1,5 @@
> >   // -*- C++ -*- std::experimental::contract_violation and friends
> > +
> >   // Copyright (C) 2019-2022 Free Software Foundation, Inc.
> >   //
> >   // This file is part of GCC.
> > @@ -23,19 +24,46 @@
> >   // <http://www.gnu.org/licenses/>.
> >
> >   #include <experimental/contract>
> > -#include <iostream>
> > +#if _GLIBCXX_HOSTED && _GLIBCXX_VERBOSE
> > +# include <iostream>
> > +#endif
> >
> >   __attribute__ ((weak)) void
> >   handle_contract_violation (const std::experimental::contract_violation &violation)
> >   {
> > -  std::cerr << "default std::handle_contract_violation called: \n"
> > -    << " " << violation.file_name()
> > -    << " " << violation.line_number()
> > -    << " " << violation.function_name()
> > -    << " " << violation.comment()
> > -    << " " << violation.assertion_level()
> > -    << " " << violation.assertion_role()
> > -    << " " << (int)violation.continuation_mode()
> > -    << std::endl;
> > +#if _GLIBCXX_HOSTED && _GLIBCXX_VERBOSE
> > +  bool level_default_p = violation.assertion_level() == "default";
> > +  bool role_default_p = violation.assertion_role() == "default";
> > +  bool cont_mode_default_p = violation.continuation_mode()
> > +    == std::experimental::contract_violation_continuation_mode::never_continue;
> > +
> > +  const char* modes[]{ "off", "on" }; // Must match enumerators in header.
> > +  std::cerr << "contract violation in function " << violation.function_name()
> > +    << " at " << violation.file_name() << ':' << violation.line_number()
> > +    << ": " << violation.comment();
> > +
> > +  const char* delimiter = "\n[";
> > +
> > +  if (!level_default_p)
> > +    {
> > +      std::cerr << delimiter << "level:" << violation.assertion_level();
> > +      delimiter = ", ";
> > +    }
> > +  if (!role_default_p)
> > +    {
> > +      std::cerr << delimiter << "role:" << violation.assertion_role();
> > +      delimiter = ", ";
> > +    }
> > +  if (!cont_mode_default_p)
> > +    {
> > +      std::cerr << delimiter << "continue:"
> > +             << modes[(int)violation.continuation_mode() & 1];
> > +      delimiter = ", ";
> > +    }
> > +
> > +  if (delimiter[0] == ',')
> > +    std::cerr << ']';
> > +
> > +  std::cerr << std::endl;
> > +#endif
> >   }
> > -
>