libcxxrt seems to lack some features that are present in libc++abi

[David Chisnall]

On 29 Jul 2017, at 17:55, Dimitry Andric <dim at FreeBSD.org> wrote:
> 
> The demangler in libcxxrt is indeed rather old, and we should replace it
> with something newer.  I'm not sure if the demangler of libc++abi is the
> right one yet, since upstream seems to still be discussing which of
> their three (or thereabouts) demanglers should be *the* LLVM demangler.
> 
> Ed, IIRC you had some looks at this before, do you have any preference?

I spoke to the ELF Toolchain maintainer a little while ago and pointed out that the demangler that we got from there lacked some features.  Maybe we can persuade him to add support for r-value references?

Ideally, I’d like to make the one in libcxxrt a weak symbol and ship the LLVM one in a separate library - it’s very big, so linking it into things like devd would be silly, but anything that’s dynamically linking libc++ would probably not notice the increase in code size.

David