[gdb/build] Fix gdbserver build with -fsanitize=thread

  Hi,

When building gdbserver with -fsanitize=thread (added to CFLAGS/CXXFLAGS) we
run into:
...
ld: ../libiberty/libiberty.a(safe-ctype.o): warning: relocation against \
  `__tsan_init' in read-only section `.text'
ld: ../libiberty/libiberty.a(safe-ctype.o): relocation R_X86_64_PC32 \
  against symbol `__tsan_init' can not be used when making a shared object; \
  recompile with -fPIC
ld: final link failed: bad value
collect2: error: ld returned 1 exit status
make[1]: *** [libinproctrace.so] Error 1
...
which looks similar to what is described in commit 78e49486944 ("[gdb/build]
Fix gdbserver build with -fsanitize=address").

The gdbserver component builds a shared library libinproctrace.so, which uses
libiberty and therefore requires the pic variant.  The gdbserver Makefile is
setup to use this variant, if available, but it's not there.

Fix this by listing gdbserver in the toplevel configure alongside libcc1, as a
component that needs the libiberty pic variant, setting:
...
extra_host_libiberty_configure_flags=--enable-shared
...

Tested on x86_64-linux.

OK for trunk gcc?

Thanks,
- Tom

[gdb/build] Fix gdbserver build with -fsanitize=thread

---
 configure    | 2 +-
 configure.ac | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
  

On Sat, Jun 25, 2022 at 11:09 AM Tom de Vries via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi,
>
> When building gdbserver with -fsanitize=thread (added to CFLAGS/CXXFLAGS) we
> run into:
> ...
> ld: ../libiberty/libiberty.a(safe-ctype.o): warning: relocation against \
>   `__tsan_init' in read-only section `.text'
> ld: ../libiberty/libiberty.a(safe-ctype.o): relocation R_X86_64_PC32 \
>   against symbol `__tsan_init' can not be used when making a shared object; \
>   recompile with -fPIC
> ld: final link failed: bad value
> collect2: error: ld returned 1 exit status
> make[1]: *** [libinproctrace.so] Error 1
> ...
> which looks similar to what is described in commit 78e49486944 ("[gdb/build]
> Fix gdbserver build with -fsanitize=address").
>
> The gdbserver component builds a shared library libinproctrace.so, which uses
> libiberty and therefore requires the pic variant.  The gdbserver Makefile is
> setup to use this variant, if available, but it's not there.
>
> Fix this by listing gdbserver in the toplevel configure alongside libcc1, as a
> component that needs the libiberty pic variant, setting:
> ...
> extra_host_libiberty_configure_flags=--enable-shared
> ...
>
> Tested on x86_64-linux.
>
> OK for trunk gcc?

OK

> Thanks,
> - Tom
>
> [gdb/build] Fix gdbserver build with -fsanitize=thread
>
> ---
>  configure    | 2 +-
>  configure.ac | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/configure b/configure
> index 1badcb314f8..aac80b88d70 100755
> --- a/configure
> +++ b/configure
> @@ -6964,7 +6964,7 @@ fi
>  extra_host_libiberty_configure_flags=
>  extra_host_zlib_configure_flags=
>  case " $configdirs " in
> -  *" lto-plugin "* | *" libcc1 "*)
> +  *" lto-plugin "* | *" libcc1 "* | *" gdbserver "*)
>      # When these are to be built as shared libraries, the same applies to
>      # libiberty.
>      extra_host_libiberty_configure_flags=--enable-shared
> diff --git a/configure.ac b/configure.ac
> index 5b6e2048514..29f74d10b5a 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -2344,7 +2344,7 @@ fi
>  extra_host_libiberty_configure_flags=
>  extra_host_zlib_configure_flags=
>  case " $configdirs " in
> -  *" lto-plugin "* | *" libcc1 "*)
> +  *" lto-plugin "* | *" libcc1 "* | *" gdbserver "*)
>      # When these are to be built as shared libraries, the same applies to
>      # libiberty.
>      extra_host_libiberty_configure_flags=--enable-shared