[PATCH v2 2/4] Optimize __libc_tsd_* thread variable access

[Frederic Berat]

Le 20/12/2024 à 07:16, Florian Weimer a écrit :
> These variables are not exported, and libc.so TLS is initial-exec
> anyway.  Declare these variables as hidden and use the initial-exec
> TLS model.

LGTM.

Reviewed-by: Frédéric Bérat <fberat@redhat.com>

> ---
>   include/ctype.h     | 9 ++++++---
>   include/rpc/rpc.h   | 3 ++-
>   locale/localeinfo.h | 3 ++-
>   3 files changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/include/ctype.h b/include/ctype.h
> index e993adc86d..0f6e7fc7ea 100644
> --- a/include/ctype.h
> +++ b/include/ctype.h
> @@ -29,9 +29,12 @@ libc_hidden_proto (toupper)
>   #   define CTYPE_EXTERN_INLINE extern inline
>   #  endif
>   
> -extern __thread const uint16_t * __libc_tsd_CTYPE_B;
> -extern __thread const int32_t * __libc_tsd_CTYPE_TOUPPER;
> -extern __thread const int32_t * __libc_tsd_CTYPE_TOLOWER;
> +extern __thread const uint16_t * __libc_tsd_CTYPE_B
> +  attribute_hidden attribute_tls_model_ie;
> +extern __thread const int32_t * __libc_tsd_CTYPE_TOUPPER
> +  attribute_hidden attribute_tls_model_ie;
> +extern __thread const int32_t * __libc_tsd_CTYPE_TOLOWER
> +  attribute_hidden attribute_tls_model_ie;
>   
>   
>   CTYPE_EXTERN_INLINE const uint16_t ** __attribute__ ((const))
> diff --git a/include/rpc/rpc.h b/include/rpc/rpc.h
> index 936ea3cebb..ba967833ad 100644
> --- a/include/rpc/rpc.h
> +++ b/include/rpc/rpc.h
> @@ -45,7 +45,8 @@ extern void __rpc_thread_key_cleanup (void) attribute_hidden;
>   
>   extern void __rpc_thread_destroy (void) attribute_hidden;
>   
> -extern __thread struct rpc_thread_variables *__libc_tsd_RPC_VARS;
> +extern __thread struct rpc_thread_variables *__libc_tsd_RPC_VARS
> +  attribute_hidden attribute_tls_model_ie;
>   
>   #define RPC_THREAD_VARIABLE(x) (__rpc_thread_variables()->x)
>   
> diff --git a/locale/localeinfo.h b/locale/localeinfo.h
> index bc8e92e4dc..c3249d3715 100644
> --- a/locale/localeinfo.h
> +++ b/locale/localeinfo.h
> @@ -237,7 +237,8 @@ extern struct __locale_struct _nl_global_locale attribute_hidden;
>   /* This fetches the thread-local locale_t pointer, either one set with
>      uselocale or &_nl_global_locale.  */
>   #define _NL_CURRENT_LOCALE	__libc_tsd_LOCALE
> -extern __thread locale_t __libc_tsd_LOCALE;
> +extern __thread locale_t __libc_tsd_LOCALE
> +  attribute_hidden attribute_tls_model_ie;
>   
>   /* For static linking it is desireable to avoid always linking in the code
>      and data for every category when we can tell at link time that they are