[PATCH] elf: Don't load archive element after dynamic definition

[H.J. Lu]

On Wed, Sep 2, 2020 at 7:29 AM Alan Modra <amodra@gmail.com> wrote:
>
> On Wed, Sep 02, 2020 at 06:22:08AM -0700, H.J. Lu wrote:
> > > It's reasonably obvious that we need to load archive elements when
> > > they define IR referenced symbols, because the archive element might
> > > be an LTO object.  What's not so obvious is whether loading of shared
> > > libraries should follow the same rule.  I think they should, in order
> > > for LTO to get symbol resolution correct in corner cases.  Basically
> > > LTO needs to know what shared libraries are loaded before
> > > recompilation.  See commit a896df97b952 log comments.
> >
> > There is dynamic_def for this purpose.
>
> Your patch doesn't make changes to ld/plugin.c to inform LTO of the
> availability of these symbols.  And if you did, then how does the
> linker work out whether or not the LTO recompilation depended on those
> symbols?  If it did change LTO recompilation then you had better
> ensure the library really is loaded.  By the time you work all of that
> out, if it is even possible, your patch will likely be very
> complicated indeed.

A testcase?


-- 
H.J.