This is the mail archive of the
mailing list for the glibc project.
Re: RFC: PATCHES: Properly handle reference to protected data on x86
- From: Alan Modra <amodra at gmail dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, GNU C Library <libc-alpha at sourceware dot org>, Binutils <binutils at sourceware dot org>
- Date: Sat, 7 Mar 2015 10:45:49 +1030
- Subject: Re: RFC: PATCHES: Properly handle reference to protected data on x86
- Authentication-results: sourceware.org; auth=none
- References: <CAMe9rOoKS4BwBSd2T+bcchYOykZ7Gzh2jCMC5J6r0qyEX1u0_Q at mail dot gmail dot com> <20150306041931 dot GE25172 at bubble dot grove dot modra dot org> <CAMe9rOqjWSWgiaGKrQjkAMymFFETF-uSwnWUWOxwJpS58arzEg at mail dot gmail dot com>
On Fri, Mar 06, 2015 at 05:04:56AM -0800, H.J. Lu wrote:
> On Thu, Mar 5, 2015 at 8:19 PM, Alan Modra <email@example.com> wrote:
> > On Wed, Mar 04, 2015 at 03:26:10PM -0800, H.J. Lu wrote:
> >> Protected symbol means that it can't be pre-emptied. It
> >> doesn't mean its address won't be external. This is true
> >> for pointer to protected function. With copy relocation,
> >> address of protected data defined in the shared library may
> >> also be external. We only know that for sure at run-time.
> >> Here are patches for glibc, binutils and GCC to handle it
> >> properly.
> >> Any comments?
> > I'd like to see this pass some more tests. For example
> > reference in non-PIC exe to var x
> > protected visibility definition of x in libA
> > protected visibility definition of x in libB
> > I suspect you don't have this case correct, but congratulations if you
> > do! Assuming libA is first on the breadth first search for libraries,
> > then exe and libA ought to use the same x, but libB have its own x.
> I believe my new testcases on hjl/pr17711 branch at
> covers those and they work correctly.
The test that I see in commit 9ea148bb does not. Please notice that
I'm asking you about two protected definitions in the libraries, not
one protected and one with default visibility.
Australia Development Lab, IBM