| /* Definition of __INDIRECT_RETURN. x86 version. |
| Copyright (C) 2018-2021 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <https://www.gnu.org/licenses/>. */ |
| |
| #ifndef _UCONTEXT_H |
| # error "Never include <bits/indirect-return.h> directly; use <ucontext.h> instead." |
| #endif |
| |
| /* On x86, swapcontext returns via indirect branch when the shadow stack |
| is enabled. Define __INDIRECT_RETURN to indicate whether swapcontext |
| returns via indirect branch. */ |
| #if defined __CET__ && (__CET__ & 2) != 0 |
| # if __glibc_has_attribute (__indirect_return__) |
| # define __INDIRECT_RETURN __attribute__ ((__indirect_return__)) |
| # else |
| /* Newer compilers provide the indirect_return attribute, but without |
| it we can use returns_twice to affect the optimizer in the same |
| way and avoid unsafe optimizations. */ |
| # define __INDIRECT_RETURN __attribute__ ((__returns_twice__)) |
| # endif |
| #else |
| # define __INDIRECT_RETURN |
| #endif |
