[cfe-dev] [LLVMdev] [3.5 Release] Release Candidate 4 Now Available

[Dan Albert]

libc++abi can only be compiled by clang. __sync_swap() is a clang builtin.
I believe the conclusion of the discussion about replacing those calls with
std::atomic ended with deciding we couldn't do it, though I don't remember
why.

Looking at the source, I think the warning about uncaught exception
congress from libc++ not being able to find the libc++abi headers.

I should also mention that LLVM 3.5 has been released, and you should be
using that instead of the release candidate.
On Sep 14, 2014 6:09 AM, "Larry Evans" <cppljevans at suddenlink.net> wrote:

> On 08/28/2014 02:07 PM, Bill Wendling wrote:
> > We had to roll a release candidate 4 for the 3.5 release. It’s up at the
> normal place:
> >
> >       http://llvm.org/pre-releases/3.5
> >
> > Please test it and report any major bugs you may find.
> >
> > Thanks!
> > -bw
> >
> I tried to use libcxxabi, as downloaded from:
>
> http://llvm.org/pre-releases/3.5/rc4/libcxxabi-3.5.0rc4.src.tar.xz
>
> However, on my system:
>
> ~/dwnlds/llvm/3.5/rc4 $ uname -a
> Linux lje-OptiPlex-9020 3.13.0-35-generic #62-Ubuntu SMP Fri Aug 15
> 01:58:42 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
>
> after doing cmake then make, getting some error about missing __sync_swap:
>
>
> [ 11%] make[3]: Leaving directory
> `/home/evansl/dwnlds/llvm/3.5/rc4/build-variants/Release/cmake-build'
> Building C object
>
> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-x86_64.dir/absvti2.c.o
> make[3]: Entering directory
> `/home/evansl/dwnlds/llvm/3.5/rc4/build-variants/Release/cmake-build'
>
> /home/evansl/dwnlds/llvm/3.5/rc4/sources/llvm-3.5.0rc4.src/projects/libcxxabi/src/cxa_default_handlers.cpp:
> In function ‘void (* std::set_unexpected(std::unexpected_handler))()’:
>
> /home/evansl/dwnlds/llvm/3.5/rc4/sources/llvm-3.5.0rc4.src/projects/libcxxabi/src/cxa_default_handlers.cpp:106:52:
> error: ‘__sync_swap’ was not declared in this scope
>   return __sync_swap(&__cxa_unexpected_handler, func);
>                                                     ^
> Also, later getting warning about exception_ptr:
>
> [ 13%] Building CXX object
> projects/libcxx/lib/CMakeFiles/cxx.dir/__/src/exception.cpp.o
> [ 13%] Building C object
>
> projects/compiler-rt/lib/builtins/CMakeFiles/clang_rt.builtins-x86_64.dir/ffsdi2.c.o
>
> /home/evansl/dwnlds/llvm/3.5/rc4/sources/llvm-3.5.0rc4.src/projects/libcxx/src/exception.cpp:118:9:
> warning: #warning is a GCC extension [enabled by default]
>  #       warning uncaught_exception not yet implemented
>          ^
>
> /home/evansl/dwnlds/llvm/3.5/rc4/sources/llvm-3.5.0rc4.src/projects/libcxx/src/exception.cpp:118:9:
> warning: #warning uncaught_exception not yet implemented [-Wcpp]
>
>
> Is the __sync_swap error related to the subject of this post:
>
> http://lists.cs.uiuc.edu/pipermail/cfe-dev/2014-May/036861.html
>
> , and therefore, should the code in the downloaded
> libcxxabi-3.5.0rc4.src.tar.xz be updated?  Also, should I worry
> about the warnings?
>
> TIA.
>
> -regards,
> Larry
>
>
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