[cfe-dev] C++ Language Support Library

[Sebastian Redl]

Chris Lattner wrote:
> I think that retaining compatibility with libstdc++ would be a very 
> worthwhile goal (as is supporting the apache library, stlport, and/or 
> whatever other ones exist, where reasonable).  What is the cost of 
> doing this?  Does it use crazy GCC extensions that we don't want to 
> implement?
I think it's not only worthwhile, it's absolutely vital. If we don't 
support compiling with libstdc++ (and compile it exactly the way GCC 
does), we don't have binary compatibility for shared objects, where 
standard library types appear in interfaces. This would be bad for us, 
and bad for C++.

libstdc++ doesn't use any special GCC extensions that we don't already 
have, except in the TR1 and C++0x area. But those intrinsics we have to 
implement anyway.
The main problem is that we're playing catch-up, and libstdc++ is a 
moving target. As GCC's support for C++0x grows, so does libstdc++'s 
usage of those features. We'll probably have to be on par with GCC in 
features to compile libstdc++.

Sebastian