diff options
Diffstat (limited to 'sysdeps/x86/init-arch.h')
| -rw-r--r-- | sysdeps/x86/init-arch.h | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/sysdeps/x86/init-arch.h b/sysdeps/x86/init-arch.h index 6cbc16b7f6..15d3f0975d 100644 --- a/sysdeps/x86/init-arch.h +++ b/sysdeps/x86/init-arch.h @@ -21,6 +21,46 @@ # include <ldsodefs.h> #endif +/* These macros are used to implement ifunc selection in C. To implement + an ifunc function, foo, which returns the address of __foo_sse2 or + __foo_avx2: + + #define foo __redirect_foo + #define __foo __redirect___foo + #include <foo.h> + #undef foo + #undef __foo + #define SYMBOL_NAME foo + #include <init-arch.h> + + extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden; + extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden; + + static inline void * + foo_selector (void) + { + if (use AVX2) + return OPTIMIZE (avx2); + + return OPTIMIZE (sse2); + } + + libc_ifunc_redirected (__redirect_foo, foo, foo_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) + #ifndef __x86_64__ /* Due to the reordering and the other nifty extensions in i686, it is not really good to use heavily i586 optimized code on an i686. It's |