[PATCH 2/2] elf: Add GNU_PROPERTY_1_NEEDED check

[H.J. Lu]

On Mon, Jun 21, 2021 at 5:06 PM Alan Modra <amodra@gmail.com> wrote:
>
> On Mon, Jun 21, 2021 at 03:34:38PM -0700, Fangrui Song wrote:
> > clang -fno-pic -fno-direct-access-extern-data  works with clang>=12.0.0 today.
>
> -fno-direct-access-extern-data or variations on that also seem good to
> me.  -fpic-extern would also work.  I liked -fprotected-abi because
> it shows the intent of correcting abi issues related to protected
> visibility.  (Yes, it affects code for all undefined symbols because
> the compiler clearly isn't seeing the entire program if there are
> undefined symbols.)

I need an option which can be turned on and off.   How about
-fextern-access=direct and -fextern-access=indirect?  It will cover
both data and function?

> The main thing that struck me about -fsingle-global-definition is that
> the option doesn't do what it says.  You can still have multiple
> global definitions of a given symbol, one in the executable and one in
> each of the shared libraries making up the complete program.  Which of
> course is no different to code without -fsingle-global-definition.


-- 
H.J.