-fnew-abi and branching

[Gabriel Dos Reis]

Mark Mitchell <mark@codesourcery.com> writes:

| Folks --
| 
|   In private email, Jason suggested that doing the -fnew-abi
| development (i.e., the parts that belong to the compiler, not the bits
| we discussed regarding libio) need not be done on a branch.
|  
|   In particular, Jason opined that it would be fine to leave the
| compiler and libio out of sync on the mainline -- provided that only
| without -fnew-abi everything continued to move smoothly.
| 
|   So, his suggestion was:
| 
|   o Leave libio alone.
|   o Do -fnew-abi development on the mainline.
| 
| This will leave the mainline -fnew-abi compiler "broken" in that
| programs using libio won't work correctly, but it will avoid
| divergence in the compiler.  And, since -fnew-abi is an unsupported
| option, there's really nothing for anyone to complain about.
| 
|   Are there any objections to this proposal? 
| 
|   (It's possible that Jeff suggested this in one of his emails as
| well; it wasn't clear to me at the time.)
| 
|   If I don't hear objections in the next day or so, I'll merge the
| changes from the branch into the mainline.

On libstdc++-v3, we recommend testing '-fnew-abi' and we're planning to
make it the default.  Unless I'm mistaken, the new ABI experiment means
"official libio" and "EGCS libio" would go out of sync.  Am I right?
If so, I'd like we come up with a solution that makes it possible for
us (on libstdc++-v3) to continue to test -fnew-abi on v-3 without
breaking everything. 

Thanks,

-- Gaby