[PATCH] elf: Check multiple definition when defining hidden version

[H.J. Lu]

On Thu, Dec 3, 2020 at 4:22 PM Alan Modra <amodra@gmail.com> wrote:
>
> On Thu, Dec 03, 2020 at 05:10:51AM -0800, H.J. Lu wrote:
> > What your patch does are
> >
> > 1. Hide the weak foo@@v1.
> > 2. Change the non-weak, hidden foo@v1 to the default foo@@v1.
>
> Yes, and that is what gold does currently too.
>
> > It is the opposite of what @@ and @ are supposed to do.  I believe we
> > should reject such inputs.
>
> It would seem that you and I have a slightly different idea of what @@
> and @ mean.  I expect we'd agree on most of the normal use of symbol
> versioning, but I don't see any reason to consider the result of my ld
> fix the "opposite of what @@ and @ are supposed to do".  The mere fact
> that you claim that makes me suspect you haven't spent much time
> thinking about the problem.

My comments are based on my work with symbol versioning in glibc.

> So I'm going to commit my patch for this PR.

Instead of refusing to accept dubious inputs, ld now may generate incorrect
outputs which may be hard to track down.

FWIW, I will revert this patch in my own linker.

> PS: For anyone reading this mailing list and wondering about versioned
> symbols, I recommend Ian's excellent blog posts.  Searching
> "site:airs.com symbol version" will give you more than one article
> worth reading.
>
> --
> Alan Modra
> Australia Development Lab, IBM



-- 
H.J.