| /* IFUNC generic definitions. |
| This file is part of the GNU C Library. |
| Copyright (C) 2017-2018 Free Software Foundation, Inc. |
| |
| 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 |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* These macros are used to implement ifunc selection in C. To implement |
| an ifunc function, foo, which returns the address of __foo_impl1 or |
| __foo_impl2: |
| |
| #define foo __redirect_foo |
| #include <foo.h> |
| #undef foo |
| #define SYMBOL_NAME foo |
| #include <ifunc-init.h> |
| |
| extern __typeof (REDIRECT_NAME) OPTIMIZE (impl1) attribute_hidden; |
| extern __typeof (REDIRECT_NAME) OPTIMIZE (impl2) attribute_hidden; |
| |
| static inline void * |
| foo_selector (void) |
| { |
| if (condition) |
| return OPTIMIZE (impl2); |
| |
| return OPTIMIZE (impl1); |
| } |
| |
| libc_ifunc_redirected (__redirect_foo, foo, IFUNC_SELECTOR ()); |
| */ |
| |
| #define PASTER1(x,y) x##_##y |
| #define EVALUATOR1(x,y) PASTER1 (x,y) |
| #define PASTER2(x,y) __##x##_##y |
| #define EVALUATOR2(x,y) PASTER2 (x,y) |
| |
| /* Basically set '__redirect_<symbol>' to use as type definition, |
| '__<symbol>_<variant>' as the optimized implementation and |
| '<symbol>_ifunc_selector' as the IFUNC selector. */ |
| #define REDIRECT_NAME EVALUATOR1 (__redirect, SYMBOL_NAME) |
| #define OPTIMIZE(name) EVALUATOR2 (SYMBOL_NAME, name) |
| #define IFUNC_SELECTOR EVALUATOR1 (SYMBOL_NAME, ifunc_selector) |
