[Bug c++/105512] New: compilation with -fmodules-ts and std=c++20 leads to segfault

[Bug c++/105512] New: compilation with -fmodules-ts and std=c++20 leads to segfault

[deco33000 at yandex dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105512

            Bug ID: 105512
           Summary: compilation with -fmodules-ts and std=c++20 leads to
                    segfault
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: deco33000 at yandex dot com
  Target Milestone: ---

Hi,

compiling with -fmodules-ts and -std=c++20 leads to a segfault. With c++17 no
errors. Without std= switch, no segfault.
But c++20 is required in my code, hence the report.

Here is the reduced code:

----- main.cpp
import hello;

int main ( void ){

        X::greeter("ok");
        return 0;
}

-----mod.cxx
module;

#include <iostream>
#include <string_view>
#include <string>

export module hello;
import sub_mod;

namespace X {

                void greeter2 ( std::string_view const &name ){
                        std::string h = "exported greeter";

                        std::cout << "Bye " << name << "!" << h << "\n";
                        Y::g();

                }

        }

export {

        namespace X {

                void greeter ( std::string_view const &name ){
                        std::string h = "exported greeter";

                        std::cout << "Hello " << name << "!" << h << "\n";

                        greeter2("ff");
                }

        }
}

-----mod_sub.cxx
module;

#include <iostream>
export module sub_mod;

export {
        namespace Y {

                auto g (){

                        std::cout << "in out " << std::endl;

                }

        }
}

The following works with c++17 and c++20 flags (no issue):

----- mod_sub.cxx corrected (no global fragment):
export module sub_mod;

export {
        namespace Y {

                auto g ()-> int{

                        //std::cout << "in out " << std::endl;
                        return 54;

                }

        }
}

and

----- mod.cxx corrected (prints g() directly):
module;

#include <iostream>
#include <string_view>
#include <string>

export module hello;
import sub_mod;

namespace X {

                void greeter2 ( std::string_view const &name ){
                        std::string h = "exported greeter";

                        std::cout << "Bye " << name << "!" << h << " " <<
Y::g() <<"\n";


                }

        }

export {

        namespace X {

                void greeter ( std::string_view const &name ){
                        std::string h = "exported greeter";

                        std::cout << "Hello " << name << "!" << h << "\n";

                        greeter2("ff");
                }

        }
}

Thanks,

[Bug c++/105512] compilation with -fmodules-ts and std=c++20 leads to segfault

[gnu.w2nnu at simplelogin dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105512

David Truby <gnu.w2nnu at simplelogin dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gnu.w2nnu at simplelogin dot com

--- Comment #1 from David Truby <gnu.w2nnu at simplelogin dot com> ---
I also see this issue and have a reproducer here:
---- main.cpp
#include <iostream>
#include <string>
import test;

int main() {
        std::cout << tester();
}

---- test.cpp
module; 
#include <string>
export module test;

export std::string tester() {
        return "hello world\n";
}

----

Interestingly the issue also goes away if -D_GLIBCXX_USE_CXX11_ABI=0 is passed
to both TUs so I suspect there's an issue with the module file not exporting
the correct ABI for `std::string`

[Bug c++/105512] compilation with -fmodules-ts and std=c++20 leads to segfault

[mail@gerrit-albrecht.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105512

Gerrit Albrecht <mail@gerrit-albrecht.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mail@gerrit-albrecht.de

--- Comment #2 from Gerrit Albrecht <mail@gerrit-albrecht.de> ---
Hi. I can confirm both reports. Tried it with "g++.exe (Rev2, Built by MSYS2
project) 13.2.0" MinGW64 compiler; both -std=c++23 and -std=c++20 segfault
together with -fmodules-ts. It works without -std option and with
D_GLIBCXX_USE_CXX11_ABI=0. Thanks.

[Bug c++/105512] compilation with -fmodules-ts and std=c++20 leads to segfault

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105512

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-03-06
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=110730
             Status|UNCONFIRMED                 |ASSIGNED
                 CC|                            |ppalka at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot gnu.org

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
(In reply to David Truby from comment #1)
> Interestingly the issue also goes away if -D_GLIBCXX_USE_CXX11_ABI=0 is
> passed to both TUs so I suspect there's an issue with the module file not
> exporting the correct ABI for `std::string`

Good catch, so this is the same underlying issue as in PR110730.

[Bug c++/105512] compilation with -fmodules-ts and std=c++20 leads to segfault

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105512

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:0552560f6d2eaa1ae6df5c80660b489de1d5c772

commit r14-9372-g0552560f6d2eaa1ae6df5c80660b489de1d5c772
Author: Patrick Palka <ppalka@redhat.com>
Date:   Thu Mar 7 16:23:22 2024 -0500

    c++/modules: inline namespace abi_tag streaming [PR110730]

    The unreduced testcase from PR110730 crashes at runtime ultimately
    because we don't stream the abi_tag attribute on inline namespaces and
    so the filesystem::current_path() call resolves to the non-C++11 ABI
    version even though the C++11 ABI is active, leading to a crash when
    destroying the path temporary (which contains an std::string member).
    Similar story for the PR105512 testcase.

    While we do stream the DECL_ATTRIBUTES of all decls that go through
    the generic tree streaming routines, it seems namespaces are streamed
    separately from other decls and we don't use the generic routines for
    them.  So this patch makes us stream the abi_tag manually for (inline)
    namespaces.

            PR c++/110730
            PR c++/105512

    gcc/cp/ChangeLog:

            * module.cc (module_state::write_namespaces): Stream the
            abi_tag attribute of an inline namespace.
            (module_state::read_namespaces): Likewise.

    gcc/testsuite/ChangeLog:

            * g++.dg/modules/hello-2_a.C: New test.
            * g++.dg/modules/hello-2_b.C: New test.
            * g++.dg/modules/namespace-6_a.H: New test.
            * g++.dg/modules/namespace-6_b.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>

[Bug c++/105512] compilation with -fmodules-ts and std=c++20 leads to segfault

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105512

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|---                         |14.0
         Resolution|---                         |FIXED

--- Comment #5 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 14, thanks for the bug reports.