| Message ID | 20200213113824.32309-1-adhemerval.zanella@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [COMMITTED] alpha: Fix static gettimeofday symbol | expand |
* Adhemerval Zanella: > By undef strong_alias on alpha implementation, the > default_symbol_version macro becomes an empty macro on static build. > It fixes the issue introduced at c953219420. Aren't we using a different mechanism for this in other cases? Like defining macros for the alias targets? In any case, SET_VERSION for this macro isn't very descriptive. Thanks, Florian
On 13/02/2020 09:04, Florian Weimer wrote: > * Adhemerval Zanella: > >> By undef strong_alias on alpha implementation, the >> default_symbol_version macro becomes an empty macro on static build. >> It fixes the issue introduced at c953219420. > > Aren't we using a different mechanism for this in other cases? > Like defining macros for the alias targets? > > In any case, SET_VERSION for this macro isn't very descriptive. I don't have a strong opinion here, on some ifunc variant definitions some implementation undef/redefine the alias macros. The problems with this approach are: 1. once you have composed macros (such as default_symbol_version). 2. if you want to use the same macro you need to undef after the common case inclusion. On both cases you will need to redefined it using libc-symbol.h internals which defeats the usage of such macros imho (for instance the usage of _weak_alias or any other internal macros). So I start to see that just avoid messing with macro undef/def usually is a cleaner solution.
* Adhemerval Zanella: > On 13/02/2020 09:04, Florian Weimer wrote: >> * Adhemerval Zanella: >> >>> By undef strong_alias on alpha implementation, the >>> default_symbol_version macro becomes an empty macro on static build. >>> It fixes the issue introduced at c953219420. >> >> Aren't we using a different mechanism for this in other cases? >> Like defining macros for the alias targets? >> >> In any case, SET_VERSION for this macro isn't very descriptive. > > I don't have a strong opinion here, on some ifunc variant definitions > some implementation undef/redefine the alias macros. The problems with > this approach are: > > 1. once you have composed macros (such as default_symbol_version). > > 2. if you want to use the same macro you need to undef after the > common case inclusion. > > On both cases you will need to redefined it using libc-symbol.h > internals which defeats the usage of such macros imho (for instance > the usage of _weak_alias or any other internal macros). I thought we had cases where we redefined the *target* identifiers of these aliases, but maybe I'm wrong about that. But I'm sure we have cases somewhere where we have a -common.c file which contains the code, without the aliases. Thanks, Florian
On 13/02/2020 09:37, Florian Weimer wrote: > * Adhemerval Zanella: > >> On 13/02/2020 09:04, Florian Weimer wrote: >>> * Adhemerval Zanella: >>> >>>> By undef strong_alias on alpha implementation, the >>>> default_symbol_version macro becomes an empty macro on static build. >>>> It fixes the issue introduced at c953219420. >>> >>> Aren't we using a different mechanism for this in other cases? >>> Like defining macros for the alias targets? >>> >>> In any case, SET_VERSION for this macro isn't very descriptive. >> >> I don't have a strong opinion here, on some ifunc variant definitions >> some implementation undef/redefine the alias macros. The problems with >> this approach are: >> >> 1. once you have composed macros (such as default_symbol_version). >> >> 2. if you want to use the same macro you need to undef after the >> common case inclusion. >> >> On both cases you will need to redefined it using libc-symbol.h >> internals which defeats the usage of such macros imho (for instance >> the usage of _weak_alias or any other internal macros). > > I thought we had cases where we redefined the *target* identifiers of > these aliases, but maybe I'm wrong about that. > > But I'm sure we have cases somewhere where we have a -common.c file > which contains the code, without the aliases. It might be a better option, I will prepare a patch.
On 13/02/2020 09:37, Florian Weimer wrote: > * Adhemerval Zanella: > >> On 13/02/2020 09:04, Florian Weimer wrote: >>> * Adhemerval Zanella: >>> >>>> By undef strong_alias on alpha implementation, the >>>> default_symbol_version macro becomes an empty macro on static build. >>>> It fixes the issue introduced at c953219420. >>> >>> Aren't we using a different mechanism for this in other cases? >>> Like defining macros for the alias targets? >>> >>> In any case, SET_VERSION for this macro isn't very descriptive. >> >> I don't have a strong opinion here, on some ifunc variant definitions >> some implementation undef/redefine the alias macros. The problems with >> this approach are: >> >> 1. once you have composed macros (such as default_symbol_version). >> >> 2. if you want to use the same macro you need to undef after the >> common case inclusion. >> >> On both cases you will need to redefined it using libc-symbol.h >> internals which defeats the usage of such macros imho (for instance >> the usage of _weak_alias or any other internal macros). > > I thought we had cases where we redefined the *target* identifiers of > these aliases, but maybe I'm wrong about that. It works if the generic alias match the expected override code, once you need to remove/redefine some alias (such as the gettimeofday code) it becomes quite complex to handle it.
diff --git a/sysdeps/unix/sysv/linux/alpha/gettimeofday.c b/sysdeps/unix/sysv/linux/alpha/gettimeofday.c index 7ad3c6a412..25e86410fd 100644 --- a/sysdeps/unix/sysv/linux/alpha/gettimeofday.c +++ b/sysdeps/unix/sysv/linux/alpha/gettimeofday.c @@ -18,12 +18,9 @@ /* We can use the generic implementation, but we have to override its default symbol version. */ -#undef weak_alias -#define weak_alias(a,b) -#undef strong_alias -#define strong_alias(a, b) +#define SET_VERSION #include <time/gettimeofday.c> -_weak_alias (___gettimeofday, __wgettimeofday); +weak_alias (___gettimeofday, __wgettimeofday); default_symbol_version (___gettimeofday, __gettimeofday, GLIBC_2.1); default_symbol_version (__wgettimeofday, gettimeofday, GLIBC_2.1); diff --git a/time/gettimeofday.c b/time/gettimeofday.c index 07c6e10d12..e4671edd13 100644 --- a/time/gettimeofday.c +++ b/time/gettimeofday.c @@ -35,6 +35,8 @@ ___gettimeofday (struct timeval *restrict tv, void *restrict tz) TIMESPEC_TO_TIMEVAL (tv, &ts); return 0; } - +/* Define to override default symbol version. */ +#ifndef SET_VERSION strong_alias (___gettimeofday, __gettimeofday) weak_alias (___gettimeofday, gettimeofday) +#endif