[cfe-dev] Trouble building libc++

[Howard Hinnant]

On May 11, 2010, at 10:11 PM, Peter O'Gorman wrote:

> On 05/11/2010 08:59 PM, Chris Lattner wrote:
>> Internally, we have factored that code out of libstdc++ (this is
>> largely code that lives in "libsup++") into a library currently
>> called libc++abi.dylib.
> 
> What's the harm in putting that source in llvm svn also?

For the current time, Apple is going to maintain ABI compatibility of some low-level bits between libstdc++ and libc++.  This is so that clients can create applications that link to disparate dynamic libraries, some which use libstdc++, some which use libc++, and still be able to function with exceptions being thrown across dylib boundaries and one somebody replacing operator new.

With this in mind, it makes sense for us to separate out the ABI stable bits into a 3rd lib which serves an ABI (but not necessarily an API) to both libstdc++ and libc++.  As Chris mentioned, this is essentially gcc's libsup++.

-Howard