RFA (varpool): PATCH to add forward-compatibility aliases for C++ ABI bugs

[Richard Guenther]

On Thu, Feb 25, 2010 at 10:58 PM, Jason Merrill <jason@redhat.com> wrote:
> The attached patch addresses some binary compatibility issues with bugs in
> our current implementation of the C++ ABI by emitting aliases with
> ABI-compliant mangled names in addition to the names generated normally.
>
> I need review of the cgraph.h and varpool.c hunks.  They basically add the
> same capability to the varpool code that Jakub added to cgraph with the
> cgraph_same_body_alias code.  This code is much simpler, but it seems to me
> like it's enough given the relative simplicity of varpool.
>
> Tested x86_64-pc-linux-gnu.  OK for 4.5?

Apart from being cleaner does it offer any functional advantage
over using the existing alias machinery (the vector of alias_pairs
emitted via finish_aliases_*)?

In fact you probably need to adjust the LTO streamer and symtab
merger for your change (while it should handle alias_pairs already).

In principle I like the varpool change but like to see alias_pairs gone
as they look redundant after this change.

Thanks,
Richard.