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Diffstat (limited to '')
| -rw-r--r-- | include/o3tl/unreachable.hxx | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/include/o3tl/unreachable.hxx b/include/o3tl/unreachable.hxx new file mode 100644 index 0000000000..604f7a2f77 --- /dev/null +++ b/include/o3tl/unreachable.hxx @@ -0,0 +1,48 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#ifndef INCLUDED_O3TL_UNREACHABLE_HXX +#define INCLUDED_O3TL_UNREACHABLE_HXX + +#include <sal/config.h> + +#include <cassert> +#include <utility> + +// An approximation of C++23 std::unreachable +// (<http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p0627r6.pdf> "Function to mark +// unreachable code"). + +#if defined __cpp_lib_unreachable + +#define O3TL_UNREACHABLE (::std::unreachable()) + +#else + +// This fallback implementation is inspired by LLVM's LLVM_BUILTIN_UNREACHABLE +// (llvm/include/llvm/Support/Compiler.h). + +#if defined _MSC_VER +#define O3TL_UNREACHABLE_detail __assume(false) +#else // assuming Clang or GCC with support for: +#define O3TL_UNREACHABLE_detail __builtin_unreachable() +#endif + +#define O3TL_UNREACHABLE \ + do \ + { \ + assert(false); \ + O3TL_UNREACHABLE_detail; \ + } while (false) + +#endif + +#endif + +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |