[cfe-dev] libc++abi on linux

[Nick Kledzik]

On Jul 9, 2012, at 2:34 PM, Ashok Nalkund wrote:
> On 7/9/2012 2:11 PM, Richard Smith wrote:
>> On Mon, Jul 9, 2012 at 9:44 AM, Ashok Nalkund <ashoknn at qualcomm.com
>> <mailto:ashoknn at qualcomm.com>> wrote:
>>> 
>>    So could you suggest a replacement for unwind? libc++abi + libc++ still
>>    requires unwind.h, and my temporary solution is to pull it from gcc.
>> 
>> 
>> You could pull it from libunwind instead. Ultimately, it seems to me
>> that we should fix Clang's unwind.h to provide all the necessary
>> declarations. Is there any reason not to do so? The current
>> #include_next approach suggests that there might be some Darwin-specific
>> concerns there?
> 
> But is that all, just the unwind.h? The libunwind projects (PathScale or 
> nongnu website) provide more files and require compilation etc.
> 

That is what I don't understand about this thread.  Is the problem that libgcc_s.so (which implements _Unwind_* functions) does not exits on these systems?  Or is the problem that the unwind header is missing?  

I do remember on Darwin that for whatever historical reason, gcc installed libgcc_s in a public location (/usr/lib), but the unwind headers was squirreled away instead the gcc distribution along with other fix-includes headers.  So, unless clang knew where gcc was installed, it could not add the search path pointing into gcc to the standard search path.  

If the problem is just a missing unwind.h when building libc++abi on linux, we could just change libc++abi to carry its own copy unwind.h just for linux??

-Nick