20190321-pstl-integration.patch.bz2
Description: pstl integration patch
Jonathan Wakely writes:
> On 20/03/19 14:05 -0700, Thomas Rodgers wrote:
>
>>
>>Fixed a failing test.
>
> Thanks. Apart from the changelog issue I mentioned on IRC, the only
> other required change I see is in include/Makefile.am:
>
> @@ -1480,7 +1512,9 @@ install-headers:
> $(mkinstalldirs) $(DESTDIR)${host_installdir}/../ext
> for file in ${ext_host_headers}; do \
> $(INSTALL_DATA) $${file} $(DESTDIR)${host_installdir}/../ext; done
> -
> + $(mkinstalldirs) ($DESTDIR)${gxx_include_dir}/${pstl_builddir}
>
> This needs to be $(DESTDIR) not ($DESTDIR).
>
> ***
>
> I also see a couple of things that we probably can't fix for now, but
> I'll mention them anyway for later consideration.
>
> In <bits/glue_execution_defs.h> there's a local include using ""
> instead of <> (see PR libstdc++/88066 for a similar case I changed
> recently):
>
> #include "execution_defs.h"
>
> We could fix that one, but then *all* the relative includes in
> include/pstl/* use "" too. Do you think upstream would change to use
> #include <pstl/blah.h> instead of #include "blah.h" ? It looks like
> upstream uses <pstl/include/...> instead so maybe that's something to
> change in your script to import the upstream code.
>
> Even if we fix it, TBB headers use "" instead of <>. And it might not
> be a problem for any compiler except GCC, because only we support the
> silly -I- option that makes this matter.
>
>
> I also noticed that simply including <execution> (even if you don't
> use anything from it) will cause a link-time dependency on TBB:
>
> /usr/bin/ld: /tmp/ccd7w5Oo.o: in function
> `tbb::interface7::task_arena::current_thread_index()':
> /usr/include/tbb/task_arena.h:358: undefined reference to
> `tbb::interface7::internal::task_arena_base::internal_current_slot()'
> collect2: error: ld returned 1 exit status
>
> This dependency comes from <tbb/partioner.h> which is included by
> <tbb/parallel_scan.h> which is included by <bits/execution_defs.h>.
>
> I think that's OK for now, as no existing code using GCC includes the
> <execution> header (because it doesn't exist yet). It would be good if
> we can find a way to solve that eventually though. Maybe the eventual
> solution will just be a non-TBB backend using OpenMP.
>
> Exporting something like this from libstdc++.so would work, but is
> disgusting (and presumably "tbb::interface7" changes from release to
> release?"):
>
> extern "C" [[__gnu__::__weak__]]
> int
> _ZN3tbb10interface78internal15task_arena_base21internal_current_slotEv()
> { return -1; }