[MacPorts] #52585: libcxxabi -- attempts to add thread-local-storage (TLS) to <10.7 (was: libcxxabi -- attempts to add thread-local-storage (TLS) to <10.9)

[MacPorts]

#52585: libcxxabi -- attempts to add thread-local-storage (TLS) to <10.7
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  Reporter:  ken-cunningham-webuse  |      Owner:  macports-tickets@…
      Type:  defect                 |     Status:  new
  Priority:  Normal                 |  Milestone:
 Component:  ports                  |    Version:  2.3.4
Resolution:                         |   Keywords:
      Port:  libcxxabi              |
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Description changed by kencu:

Old description:

> As per the mailing list discussion, a few ports are requesting TLS which
> is not available on systems prior to 10.9. This functionality is
> implemented in libcxxabi, and there are current efforts to provide a
> fallback mechanism for this detailed on the llvm website's libcxxxabi
> pages. < https://reviews.llvm.org/D21803>.
>
> This ticket hopes to follow the attempts to get this to work.
>
> First thing I notice is that the patches above appear to apply to
> libcxxabi @3.9.0, and we're currently running @3.7.0. I first tried to
> build @3.9.0 by updating the portfile, but ran into some attempts to
> rebuild clang-3.7 which I assume to be the dependency cycle mentioned in
> the libcxxabi portfile. I could drop back to clang-3.4 and try to build
> it, I presume -- but rather than do that, I attempted to backport the
> changes into libcxxabi @3.7.0 instead.
>
> Almost all the changes are in one file, src/cxa_thread_atexit.cpp, which
> is basically completely rewritten. I was unable to apply the patch from
> the website cleanly due to changes in that file from @3.7.0, so I did it
> manually, and hopefully without error. The changes cxa_thread_atexit.cpp
> file is attached.
>
> Sadly, when building the replacement libcxxabi that is supposed to
> provide a fallback for TLS, I now get the error saying to build the file,
> the system requires TLS -- which of course is sort of a catch-22.
>
> So, working on that idea further while I post progress so far.

New description:

 As per the mailing list discussion, a few ports are requesting TLS which
 is not available on systems prior to 10.7. This functionality is
 implemented in libcxxabi, and there are current efforts to provide a
 fallback mechanism for this detailed on the llvm website's libcxxxabi
 pages. < https://reviews.llvm.org/D21803>.

 This ticket hopes to follow the attempts to get this to work.

 First thing I notice is that the patches above appear to apply to
 libcxxabi @3.9.0, and we're currently running @3.7.0. I first tried to
 build @3.9.0 by updating the portfile, but ran into some attempts to
 rebuild clang-3.7 which I assume to be the dependency cycle mentioned in
 the libcxxabi portfile. I could drop back to clang-3.4 and try to build
 it, I presume -- but rather than do that, I attempted to backport the
 changes into libcxxabi @3.7.0 instead.

 Almost all the changes are in one file, src/cxa_thread_atexit.cpp, which
 is basically completely rewritten. I was unable to apply the patch from
 the website cleanly due to changes in that file from @3.7.0, so I did it
 manually, and hopefully without error. The changes cxa_thread_atexit.cpp
 file is attached.

 Sadly, when building the replacement libcxxabi that is supposed to provide
 a fallback for TLS, I now get the error saying to build the file, the
 system requires TLS -- which of course is sort of a catch-22.

 So, working on that idea further while I post progress so far.

--

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Ticket URL: <https://trac.macports.org/ticket/52585#comment:9>
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