https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123326
--- Comment #18 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <[email protected]>: https://gcc.gnu.org/g:f8c32184b85ce71c154fa96cd5ca700aab902656 commit r16-6547-gf8c32184b85ce71c154fa96cd5ca700aab902656 Author: Jakub Jelinek <[email protected]> Date: Wed Jan 7 15:00:50 2026 +0100 libstdc++: Use gnu_inline attribute on constexpr exception methods [PR123183] As mentioned in https://gcc.gnu.org/pipermail/gcc-patches/2026-January/704712.html in the gnu::constexpr_only thread, gnu::gnu_inline attribute actually seems to work for most of what we need for C++26 constexpr exceptions (i.e. when we want out of line bodies for C++ < 26 and need to use constexpr for C++26, yet don't want for reasons mentioned in those two PRs the bodies of those constexpr methods to be emitted inline). Unfortunately clang++ doesn't handle it 100% properly and requires the redundant inline keyword to make it work (even when the methods are constexpr and thus implicilty inline), g++ doesn't require that, so the patch adds also the redundant inline keywords and not just the [[__gnu__::__gnu_inline__]] attribute. This way if something wants to inline those functions it can, but if their address is taken, we just rely on libstdc++.{so,a} to provide those (which it does as before because those TUs are compiled with older -std= modes). The earlier r16-6477-gd5743234731 commit made sure gnu::gnu_inline constexpr virtual methods can be key methods, so vtables and rtti can be emitted only in the TU defining non-gnu_inline versions of those. 2026-01-07 Jakub Jelinek <[email protected]> PR libstdc++/123183 PR libstdc++/123326 * libsupc++/exception (std::bad_exception::~bad_exception(), std::bad_exception::what()): Add inline keyword and [[__gnu__::__gnu_inline__]] attribute to the C++26 constexpr exceptions definitions. * libsupc++/exception.h (std::exception::~exception(), std::exception::what()): Likewise. * libsupc++/exception_ptr.h (std::exception_ptr::exception_ptr(void*)): Likewise. * libsupc++/nested_exception.h (std::nested_exception::~nested_exception()): Likewise. * libsupc++/typeinfo (std::bad_cast::~bad_cast(), std::bad_cast::what(), std::bad_typeid::~bad_typeid(), std::bad_typeid::what()): Likewise. * include/bits/new_except.h (std::bad_alloc::~bad_alloc(), std::bad_alloc::what(), std::bad_array_new_length::~bad_array_new_length(), std::bad_array_new_length::what()): Likewise. * include/bits/stdexcept_except.h (std::logic_error::logic_error(const string&), std::logic_error::logic_error(const char*), std::logic_error::~logic_error(), std::logic_error::what(), std::domain_error::domain_error(const string&), std::domain_error::domain_error(const char*), std::invalid_argument::invalid_argument(const string&), std::invalid_argument::invalid_argument(const char*), std::length_error::length_error(const string&), std::length_error::length_error(const char*), std::out_of_range::out_of_range(const string&), std::out_of_range::out_of_range(const char*), std::runtime_error::runtime_error(const string&), std::runtime_error::runtime_error(const char*), std::runtime_error::~runtime_error(), std::runtime_error::what(), std::overflow_error::overflow_error(const string&), std::overflow_error::overflow_error(const char*), std::overflow_error::~overflow_error(), std::underflow_error::underflow_error(const string&), std::underflow_error::underflow_error(const char*), std::underflow_error::~underflow_error()): Likewise. (std::domain_error::~domain_error(), std::invalid_argument::~invalid_argument(), std::length_error::~length_error(), std::out_of_range::~out_of_range()): Likewise. Also change _GLIBCXX_NOTHROW to noexcept on those definitions.
