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Diffstat (limited to 'include/o3tl/unreachable.hxx')
| -rw-r--r-- | include/o3tl/unreachable.hxx | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/include/o3tl/unreachable.hxx b/include/o3tl/unreachable.hxx new file mode 100644 index 000000000..bc33d34b5 --- /dev/null +++ b/include/o3tl/unreachable.hxx @@ -0,0 +1,39 @@ +/* -*- 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> + +// A better replacement for assert(false) to indicate a place in the code that should not be +// reachable. This should improve on the sometimes poor false-positive warnings emitted by +// compilers when they cannot detect that some condition flagged by assert(false) cannot occur, +// either because assert is reduced to a no-op by NDEBUG or because assert is not marked as noreturn +// in the MSVC headers. This 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 + +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |