[PATCH 2/2] PR libstdc++/86756 Move rest of std::filesystem to libstdc++.so

[Jonathan Wakely]

On 08/01/19 11:13 +0100, Christophe Lyon wrote:
>On Mon, 7 Jan 2019 at 15:14, Christophe Lyon <christophe.lyon@linaro.org> wrote:
>>
>> On Mon, 7 Jan 2019 at 13:39, Jonathan Wakely <jwakely@redhat.com> wrote:
>> >
>> > On 07/01/19 09:48 +0000, Jonathan Wakely wrote:
>> > >On 07/01/19 10:24 +0100, Christophe Lyon wrote:
>> > >>Hi Jonathan
>> > >>
>> > >>On Sun, 6 Jan 2019 at 23:37, Jonathan Wakely <jwakely@redhat.com> wrote:
>> > >>>
>> > >>>Move std::filesystem directory iterators and operations from
>> > >>>libstdc++fs.a to main libstdc++ library. These components have many
>> > >>>dependencies on OS support, which is not available on all targets. Some
>> > >>>additional autoconf checks and conditional compilation is needed to
>> > >>>ensure the files will build for all targets. Previously this code was
>> > >>>not compiled without --enable-libstdcxx-filesystem-ts but the C++17
>> > >>>components should be available for all hosted builds.
>> > >>>
>> > >>>The tests for these components no longer need to link to libstdc++fs.a,
>> > >>>but are not expected to pass on all targets. To avoid numerous failures
>> > >>>on targets which are not expected to pass the tests (due to missing OS
>> > >>>functionality) leave the dg-require-filesystem-ts directives in place
>> > >>>for now. This will ensure the tests only run for builds where the
>> > >>>filesystem-ts library is built, which presumably means some level of OS
>> > >>>support is present.
>> > >>>
>> > >>>
>> > >>>Tested x86_64-linux (old/new string ABIs, 32/64 bit), x86_64-w64-mingw32.
>> > >>>
>> > >>>Committed to trunk.
>> > >>>
>> > >>
>> > >>After this commit (r267616), I've noticed build failures for my
>> > >>newlib-based toolchains:
>> > >>aarch64-elf, arm-eabi:
>> > >>
>> > >>In file included from
>> > >>/tmp/5241593_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/src/c++17/fs_ops.cc:57:
>> > >>/tmp/5241593_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/src/c++17/../filesystem/ops-common.h:142:11:
>> > >>error: '::truncate' has not been declared
>> > >> 142 |   using ::truncate;
>> > >>     |           ^~~~~~~~
>> > >>/tmp/5241593_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/src/c++17/fs_ops.cc:
>> > >>In function 'void std::filesystem::resize_file(const
>> > >>std::filesystem::__cxx11::path&, uintmax_t, std::error_code&)':
>> > >>/tmp/5241593_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/src/c++17/fs_ops.cc:1274:19:
>> > >>error: 'truncate' is not a member of 'posix'
>> > >>1274 |   else if (posix::truncate(p.c_str(), size))
>> > >>     |                   ^~~~~~~~
>> > >>make[5]: *** [fs_ops.lo] Error 1
>> > >>
>> > >>I'm not sure if there's an obvious fix? Note that I'm using a rather
>> > >>old newlib version, if that matters.
>> > >
>> > >That's probably the reason, as I didn't see this in my tests with
>> > >newlib builds.
>> > >
>> > >The fix is to add yet another autoconf check and guard the uses of
>> > >truncate with a _GLIBCXX_USE_TRUNCATE macro. I'll do that now ...
>> >
>> >
>> > Should be fixed with this patch, committed to trunk as r267647.
>> >
>>
>> Yes, it works. Thanks!
>>
>
>Hi Jonathan,
>
>So... this was a confirmation that the GCC build succeeded, not that
>the tests pass :)
>
>And there are actually a couple new errors with my newlib-based toolchains:
>FAIL: 27_io/filesystem/operations/all.cc (test for excess errors)
>FAIL: 27_io/filesystem/operations/resize_file.cc (test for excess errors)
>FAIL: 27_io/filesystem/path/generation/normal2.cc (test for excess errors)
>which are also UNRESOLVED, because of link-time undefined reference to `chdir',
>chmod, mkdir, pathconf and getcwd.

Ah, I was assuming if <unistd.h> is present, then those basic
functions will be present. More autoconf checks needed, I guess.
That isn't hard to do, just tedious.

>On aarch64, I'm seeing an addtional:
>FAIL: 27_io/filesystem/path/compare/strings.cc execution test
>because:
>/libstdc++-v3/testsuite/27_io/filesystem/path/compare/strings.cc:39:
>void test01(): Assertion 'p.compare(p0) == p.compare(s0)' failed.

Odd, I don't know why that would be target-specific. It's probably
just latent on other targets. I'll try to reproduce it on my aarch64
system, but it will take a while to build current trunk.

If you have time, could you please apply this patch, re-run that test
(cd $target/libstdc++-v3 && make check
RUNTESTFLAGS=conformance.exp=*/path/compare/strings/cc) and send me
the output from the $target/libstdc++-v3/testsuite/libstdc++.log file?

On x86_64 I get:

Comparing  as path:-1 as string:-1
Comparing / as path:-1 as string:-1
Comparing // as path:-1 as string:-1
Comparing /. as path:-51 as string:-51
Comparing /./ as path:-51 as string:-51
Comparing /a as path:-2 as string:-2
Comparing /a/ as path:-1 as string:-1
Comparing /a// as path:-1 as string:-1
Comparing /a/b/c/d as path:1 as string:1
Comparing /a//b as path:1 as string:1
Comparing a as path:-1 as string:-1
Comparing a/b as path:-1 as string:-1
Comparing a/b/ as path:-1 as string:-1
Comparing a/b/c as path:-1 as string:-1
Comparing a/b/c.d as path:-1 as string:-1
Comparing a/b/.. as path:-1 as string:-1
Comparing a/b/c. as path:-1 as string:-1
Comparing a/b/.c as path:-1 as string:-1
PASS: 27_io/filesystem/path/compare/strings.cc execution test