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Re: PATCH: Share the dwarf2 unwind code between glibc and gcc 3.0
>>>>> "Mark" == Mark Kettenis <kettenis@science.uva.nl> writes:
> Jason Merrill <jason_merrill@redhat.com> writes:
>> I thought this was why we created libgcc_s.so--so that we wouldn't have to
>> worry about keeping the copy of libgcc in glibc up to date. Why can't
>> glibc just link against the shared libgcc?
> __frame_state_for is part of the libc.so ABI, and is no longer part of
> libgcc_s.so (and libgcc.a). We either have to roll our own version
> for glibc, or it has to be reimplemented in GCC and added back to
> libgcc.
I think it makes sense to provide it in glibc for backwards compatibility.
But it should be a wrapper around the new libgcc APIs if possible.
> Apart from that, plain linking libc.so against libgcc_s.so would
> effectively make the libgcc_s.so ABI part of the libc.so ABI. That might
> be undesirable. Then it might not... I don't have a really strong
> opinion about that.
It seems to me that including the functions in glibc itself does the same
thing, only worse. If glibc uses the libgcc interface rather than
copying it, libgcc can be updated for new gcc releases without requiring
a new glibc release as well.
We have only committed to backards compatibility for the libgcc ABI.
Extensions are still possible, even likely.
Jason