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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 Kamiński <tkaminsk@redhat.com>
78 lines
2.5 KiB
C++
78 lines
2.5 KiB
C++
// Debugging support -*- C++ -*-
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// Copyright The GNU Toolchain Authors.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file include/debugging
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* This is a Standard C++ Library header.
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*/
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#ifndef _GLIBCXX_DEBUGGING
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#define _GLIBCXX_DEBUGGING 1
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#define __glibcxx_want_debugging
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#include <bits/version.h>
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#if __cpp_lib_debugging // C++ >= 26
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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// N.B. _GLIBCXX_BEGIN_NAMESPACE_VERSION is not used here.
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/** Try to determine if the program is running under control of a debugger.
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*
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* On GNU/Linux systems this function will only return true if the program
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* is being traced by another program which is known to be a debugger.
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* This is determined by checking the command name of the tracing program
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* against a list of known debuggers, such as "gdb".
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*
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* On other POSIX-based systems, this function will return true if the
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* program is being traced by any other process, which means it can return
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* true for non-debugger utilities that use the ptrace system call.
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*
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* @since C++26
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*/
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bool
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is_debugger_present() noexcept;
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/** Stop the program with a breakpoint or debug trap.
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*
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* The details of how a breakpoint is implemented are platform-specific.
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* Some systems provide a special instruction, such as `int3` in x86.
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* When no more appropriate mechanism is available, this will stop the
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* program using `__builtin_trap()`. It might not be possible for the
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* program to continue after such a breakpoint.
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*
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* @since C++26
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*/
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void
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breakpoint() noexcept;
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/** Stop the program if it is running under control of a debugger.
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*
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* @since C++26
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*/
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void
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breakpoint_if_debugging() noexcept;
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} // namespace std
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#endif
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#endif // _GLIBCXX_DEBUGGING
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