[PATCH] libstdc++-v3: Check for TLS support on mingw

[lhmouse]

在 2021-08-31 17:02, Jonathan Wakely 写道:
> It looks like my questions about this patch never got an answer, and
> it never got applied.
> 
> Could somebody say whether TLS is enabled for native *-*-mingw*
> builds? If it is, then we definitely need to add GCC_CHECK_TLS to the
> cross-compiler config too.
> 
> For a linux-hosted x86_64-w64-mingw32 cross compiler I see TLS is not enabled:
> 
> /* Define to 1 if the target supports thread-local storage. */
> /* #undef _GLIBCXX_HAVE_TLS */
> 

I have been disabling it with `--disable-tls` for years, but... I couldn't remember why. Thread-local storage is implemented with emutls, no matter with or without this option.

Does 'thread-local storage' mean to access thread-local objects via the FS or GS register on x86? If so, then it is definitely not supported yet.


-- 
Best regards,
LIU Hao