PT_NOTE alignment, NT_GNU_PROPERTY_TYPE_0, glibc and gold

[Mark Wielaard]

On Thu, Aug 16, 2018 at 04:21:05PM +0200, Florian Weimer wrote:
> On 08/16/2018 03:39 PM, H.J. Lu wrote:
> > glibc only discards 4-byte aligned NT_GNU_PROPERTY_TYPE_0 note
> > since NT_GNU_PROPERTY_TYPE_0 note follows gABI.  If gold
> > generates 4 byte alignment, it is a gold bug.
> 
> I filed: https://sourceware.org/bugzilla/show_bug.cgi?id=23535

I don't think this is a bug in gold, but one in ld:
https://sourceware.org/bugzilla/show_bug.cgi?id=22749

In the GNU abi all ELF Notes are arrays of 32bit words
(and so 4-byte aligned). This is the same for most other
ELF systems. Making the ELF Notes fields 64bit words (and
so 8-byte aligned) in ELFCLASS64 would indeed be what gabi
literally says, but not what GNU systems, and others, follow.

Having a mix of 4-byte words and 8-byte words ELF Notes
in the same ELF file seems unnecessarily confusing and
introduces extra segments and sections.

Cheers,

Mark