[cfe-dev] libc++abi on linux

[Ben Pope]

On Tuesday, July 10, 2012 12:16 AM, Chris Lattner wrote:
>> I think it's a real shame that this is not documented for linux, I
>> suspect it is preventing the uptake of libc++ with clang on linux and
>
> I completely agree.  I really don't care for the distracting pushes towards the pathscale libraries.

OK, so on Linux, we need some kind of unwind, it seems we have options 
(I haven't tested them all):

1) libc++abi and LLVM writes (or acquires) its own unwind
2) libc++abi with http://www.nongnu.org/libunwind/
3) libc++abi with unwind.h from GCC and libgcc_s
4) Pathscale libunwind/libcxxrt

I very much doubt that list is complete.

If libc++abi, libsupc++ and libcxxrt are "equivalent" we have a few 
hybrid options, that I definitely would not suggest!

It looks like the second and third options are in common use, 2, if you 
want to be UoI (LLVM) compatible (libunwind is MIT licence) and 3, which 
is likely to "better" when linking with GCC built code.

So... Shall I just throw together some instructions on installing your 
distributions libunwind7 (or now, libunwind8) and compiling libc++ and 
libc++abi against it?  Obviously I'll make sure it works first!

I found a backport of clang-3.1 for Ubuntu 12.04 from 12.10, that seems 
to be option 3.

I guess it would be nice if there was an option to specify this in the 
build system for clang (well for libc++), which I could also look into 
making a patch for.

Chandler, would you like to make a comment on this, since you are 
messing with the CMake system?

Ben