https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119670
--- Comment #1 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:3c95766e92d6782eb945593c043a16be096707af commit r16-3445-g3c95766e92d6782eb945593c043a16be096707af Author: Jonathan Wakely <jwak...@redhat.com> Date: Thu Apr 10 17:50:59 2025 +0100 libstdc++: Implement C++26 <debugging> features [PR119670] This implements P2546R5 (Debugging Support), including the P2810R4 (is_debugger_present is_replaceable) changes, allowing std::is_debugger_present to be replaced by the program. It would be good to provide a macOS definition of is_debugger_present as per https://developer.apple.com/library/archive/qa/qa1361/_index.html but that isn't included in this change. The src/c++26/debugging.cc file defines a global volatile int which can be set by debuggers to indicate when they are attached and detached from a running process. This allows std::is_debugger_present() to give a reliable answer, and additionally allows a debugger to choose how std::breakpoint() should behave. Setting the global to a positive value will cause std::breakpoint() to use that value as an argument to std::raise, so debuggers that prefer SIGABRT for breakpoints can select that. By default std::breakpoint() will use a platform-specific action such as the INT3 instruction on x86, or GCC's __builtin_trap(). On Linux the std::is_debugger_present() function checks whether the process is being traced by a process named "gdb", "gdbserver" or "lldb-server", to try to avoid interpreting other tracing processes (such as strace) as a debugger. There have been comments suggesting this isn't desirable and that std::is_debugger_present() should just return true for any tracing process (which is the case for non-Linux targets that support the ptrace system call). libstdc++-v3/ChangeLog: PR libstdc++/119670 * acinclude.m4 (GLIBCXX_CHECK_DEBUGGING): Check for facilities needed by <debugging>. * config.h.in: Regenerate. * configure: Regenerate. * configure.ac: Use GLIBCXX_CHECK_DEBUGGING. * include/Makefile.am: Add new header. * include/Makefile.in: Regenerate. * include/bits/version.def (debugging): Add. * include/bits/version.h: Regenerate. * include/precompiled/stdc++.h: Add new header. * src/c++26/Makefile.am: Add new file. * src/c++26/Makefile.in: Regenerate. * include/std/debugging: New file. * src/c++26/debugging.cc: New file. * testsuite/19_diagnostics/debugging/breakpoint.cc: New test. * testsuite/19_diagnostics/debugging/breakpoint_if_debugging.cc: New test. * testsuite/19_diagnostics/debugging/is_debugger_present.cc: New test. * testsuite/19_diagnostics/debugging/is_debugger_present-2.cc: New test. Reviewed-by: Tomasz KamiÅski <tkami...@redhat.com>
