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| author | H.J. Lu <hjl.tools@gmail.com> | 2017-06-05 08:28:01 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2017-06-05 08:28:13 -0700 |
| commit | 9cd30491dd6d9d4c5e9372d7a5c75f78f3a11260 (patch) | |
| tree | 9bdc9658b03a2c6038871f6b19eff9838379c382 /sysdeps | |
| parent | 30cb625a21bc7ad450fdc45d1f682e2b27c353de (diff) | |
| download | glibc-9cd30491dd6d9d4c5e9372d7a5c75f78f3a11260.tar glibc-9cd30491dd6d9d4c5e9372d7a5c75f78f3a11260.tar.gz glibc-9cd30491dd6d9d4c5e9372d7a5c75f78f3a11260.tar.bz2 glibc-9cd30491dd6d9d4c5e9372d7a5c75f78f3a11260.zip | |
x86: Add macros to implement ifunce selection in C
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:
__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 ());
* sysdeps/x86/init-arch.h (PASTER1): New.
(EVALUATOR1): Likewise.
(PASTER2): Likewise.
(EVALUATOR2): Likewise.
(REDIRECT_NAME): Likewise.
(OPTIMIZE): Likewise.
(IFUNC_SELECTOR): Likewise.
Diffstat (limited to 'sysdeps')
| -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 |