Re: -fnew-abi and branching

[Gabriel Dos Reis <Gabriel dot Dos-Reis at cmla dot ens-cachan dot fr>]

Mark Mitchell <mark@codesourcery.com> writes:

[...]

|     Benjamin> concerns me, and I suspect that it is not going to be
|     Benjamin> affected. Since -fnew-abi turns on a bunch of things,
|     Benjamin> perhaps you can elaborate on what flags will and will
|     Benjamin> not work (ie, I suspect -fvtable-thunks will break, but
|     Benjamin> that -fsquangle will not really change due to the new
|     Benjamin> ABI).
|  
| Right.  Although the new ABI will specify a mangling scheme.  I
| suspect that we'll just implement it "from scratch" since the current
| mangling code is a disaster.  We really want to get the mangling
| "right" according to the spec.  That means we can decide later whether
| to support mangling, squangling, and the new scheme -- or just some
| some subset of the three.
| 
| In the short run, location of vtbl pointers will change.  Location of
| base classes will change.  Vtable layout will change.  Virtual base
| pointers will be eliminated.
| 
| Then, some run-time library changes will occur -- but in the part of
| the library that comes with EGCS.  Things like RTTI and
| exception-handling.

OK with me.

Please, when you think that some "major" changes will affect some
run-time library (especially as far as v3 is concerned) could you ping
the libstdc++-v3 list?  This is for documentation purpose...

Thanks,

-- Gaby