On Thu, 31 Aug 2023 at 16:26, Christophe Lyon
<christophe.lyon@linaro.org> wrote:
>
> As discussed in PR104167 (comments #8 and below), and PR111238, using
> -Wl,-gc-sections in the libstdc++ testsuite for arm-eabi
> (cross-toolchain) avoids link failures for a few tests:
>
> 27_io/filesystem/path/108636.cc

I think this one probably just needs { dg-require-filesystem-ts "" }
because there's no point testing that we can link to the
std::filesystem definitions if some of those definitions are unusable
on the target.

// { dg-additional-options "-Wl,--gc-sections" { target gc_sections } }

For the rest of them, does the attached patch help? If arm-eabi
doesn't define _GLIBCXX_HAVE_READLINK then there's no point even
trying to call filesystem::read_symlink. We can avoid a useless
dependency on it by reusing the same preprocessor condition that
filesystem::read_symlink uses.

> std/time/clock/gps/1.cc
> std/time/clock/gps/io.cc
> std/time/clock/tai/1.cc
> std/time/clock/tai/io.cc
> std/time/clock/utc/1.cc
> std/time/clock/utc/io.cc
> std/time/clock/utc/leap_second_info.cc
> std/time/exceptions.cc
> std/time/format.cc
> std/time/time_zone/get_info_local.cc
> std/time/time_zone/get_info_sys.cc
> std/time/tzdb/1.cc
> std/time/tzdb/leap_seconds.cc
> std/time/tzdb_list/1.cc
> std/time/zoned_time/1.cc
> std/time/zoned_time/custom.cc
> std/time/zoned_time/io.cc
> std/time/zoned_traits.cc
>
> This patch achieves this by calling GLIBCXX_CHECK_LINKER_FEATURES in
> cross-build cases, like we already do for native builds. We keep not
> doing so in Canadian-cross builds.
>
> However, this would hide the fact that libstdc++ somehow forces the
> user to use -Wl,-gc-sections to avoid undefined references to chdir,
> mkdir, chmod, pathconf, ... so maybe it's better to keep the status
> quo and not apply this patch?

I'm undecided about this for now, but let's wait for HP's cris-elf
testing anyway.