PATCH: Share the dwarf2 unwind code between glibc and gcc 3.0

[Geoff Keating]

"H . J . Lu" <hjl@lucon.org> writes:

> Here is my gcc patch to share the dwarf2 unwind code between glibc and
> gcc. I will send patches for gcc 2.95/2.96 to do the same. Combine them
> together in glibc, glibc can support mixed v2 and v3 unwind frames,
> independent of the gcc version used to compile glibc.

Before this patch is approved, I want to see an English explanation of
the resulting design, not just uncommented code spread across two
projects.  I recommend documenting this in the GCC and glibc manuals.
I am willing to help write the documentation if you can explain the
new design to me.  I will VIOLENTLY OBJECT to this patch being
committed without proper documentation!!!!

Why does GCC need this patch?  Shouldn't the patch be against glibc?

I don't understand what you mean by "share the dwarf2 unwind code".
There should be only one copy on a system at a time.  Either that copy
is from GCC or from glibc, but if there is only one of it, the copy
cannot come from two places.  

I would recommend putting the code in glibc.  glibc needs to be
compatible with many compiler versions, but GCC 3.0 does not need to
be compatible with pre-GCC-3.0 compilers, especially on non-Linux
systems.

>From a user's point of view, if this code is updated, it should not be
necessary to rebuild both GCC and glibc.  One or the other, but not
both.

I would also suggest having the documentation written and approved
first, before the patch goes in.  This will save the trouble of
backing the patch out later if it turns out the design could be
improved.

-- 
- Geoffrey Keating <geoffk@geoffk.org>