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RE: [PATCH, MIPS] Support shared library debug with MIPS PIE (glibc)
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Matthew Fortune <Matthew dot Fortune at imgtec dot com>
- Cc: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>
- Date: Tue, 23 Jun 2015 15:27:54 +0000
- Subject: RE: [PATCH, MIPS] Support shared library debug with MIPS PIE (glibc)
- Authentication-results: sourceware.org; auth=none
- References: <6D39441BF12EF246A7ABCE6654B0235321175F69 at LEMAIL01 dot le dot imgtec dot org> <alpine dot DEB dot 2 dot 10 dot 1506231512570 dot 4489 at digraph dot polyomino dot org dot uk> <6D39441BF12EF246A7ABCE6654B02353211760CF at LEMAIL01 dot le dot imgtec dot org>
On Tue, 23 Jun 2015, Matthew Fortune wrote:
> > What if there are both DT_MIPS_RLD_MAP2 and DT_MIPS_RLD_MAP? Will that
> > never happen?
>
> That will happen for executables much like MIPS has an unused DT_DEBUG
> entry. I figured it would be better to add DT_MIPS_RLD_MAP2 to all
> executables allowing this to be the only tag supported by dynamic linkers
> that may not care about compatibility with pre-existing executables.
>
> Are you thinking there should be a consistency check that the two tags
> lead to the same address? I guess there would be no harm in that but
> equally it may not be of much value. What do you think?
Are you saying that glibc never needs to handle both because if both are
present they will point to the same address and so new glibc, looking only
at DT_MIPS_RLD_MAP2, will work fine (for non-PIE) with old GDB?
If so, the patch is OK if the binutils patch is approved.
--
Joseph S. Myers
joseph@codesourcery.com