[PATCH] i386: Add GLIBC_ABI_GNU_TLS version [BZ #33221]

[Sam James]

"H.J. Lu" <hjl.tools@gmail.com> writes:

> On i386, programs and shared libraries with __thread usage may fail
> silently at run-time against glibc without the TLS run-time fix for:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=32996
>
> Add GLIBC_ABI_GNU_TLS version to indicate that glibc has the working
> GNU TLS run-time.  Linker can add the GLIBC_ABI_GNU_TLS version to
> binaries which depend on the working TLS run-time so that such programs
> and shared libraries will fail to load and run at run-time against
> libc.so without the GLIBC_ABI_GNU_TLS version, instead of fail silently
> at random.
>
> This fixes BZ #33221.
>

LGTM. Thanks.

Reviewed-by: Sam James <sam@gentoo.org>

> Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
> ---
>  sysdeps/i386/Makefile | 9 +++++++++
>  sysdeps/i386/Versions | 5 +++++
>  2 files changed, 14 insertions(+)
>
> diff --git a/sysdeps/i386/Makefile b/sysdeps/i386/Makefile
> index ee6470d78e..c0c017b899 100644
> --- a/sysdeps/i386/Makefile
> +++ b/sysdeps/i386/Makefile
> @@ -60,6 +60,15 @@ $(objpfx)tst-ld-sse-use.out: ../sysdeps/i386/tst-ld-sse-use.sh $(objpfx)ld.so
>  	@echo "Checking ld.so for SSE register use.  This will take a few seconds..."
>  	$(BASH) $< $(objpfx) '$(NM)' '$(OBJDUMP)' '$(READELF)' > $@; \
>  	$(evaluate-test)
> +
> +tests-special += $(objpfx)check-gnu-tls.out
> +
> +$(objpfx)check-gnu-tls.out: $(common-objpfx)libc.so
> +	LC_ALL=C $(READELF) -V -W $< \
> +		| sed -ne '/.gnu.version_d/, /.gnu.version_r/ p' \
> +		| grep GLIBC_ABI_GNU_TLS > $@; \
> +	$(evaluate-test)
> +generated += check-gnu-tls.out
>  else
>  CFLAGS-.os += $(if $(filter rtld-%.os,$(@F)), $(rtld-CFLAGS))
>  endif
> diff --git a/sysdeps/i386/Versions b/sysdeps/i386/Versions
> index 36e23b466a..9c84c8ef04 100644
> --- a/sysdeps/i386/Versions
> +++ b/sysdeps/i386/Versions
> @@ -28,6 +28,11 @@ libc {
>    GLIBC_2.13 {
>      __fentry__;
>    }
> +  GLIBC_ABI_GNU_TLS {
> +    # This symbol is used only for empty version map and will be removed
> +    # by scripts/versions.awk.
> +    __placeholder_only_for_empty_version_map;
> +  }
>  }
>  libm {
>    GLIBC_2.1 {