On Wed, Apr 21, 2021 at 12:32:42PM +0200, Jan Beulich wrote: > On 21.04.2021 10:52, Roger Pau Monné wrote: > > On Thu, Apr 01, 2021 at 11:44:45AM +0200, Jan Beulich wrote: > >> PE binaries specify section addresses by (32-bit) RVA. GNU ld up to at > >> least 2.36 would silently truncate the (negative) difference when a > >> section is placed below the image base. Such sections would also be > >> wrongly placed ahead of all "normal" ones. Since, for the time being, > >> we build xen.efi with --strip-debug anyway, .stab* can't appear. And > >> .comment has an entry in /DISCARD/ already anyway in the EFI case. > >> > >> Because of their unclear origin, keep the directives for the ELF case > >> though. > > > > It's my understadng thonse sections are only there for debug purposes, > > and never part of the final xen binary as they are stripped? > > > > Could we maybe remove the section load address of 0 and instead just > > use the (NOLOAD) directive? > > (NOLOAD) is meaningless for PE. > > > Does it really matter to place them at address 0? > > That's the convention for ELF, and also what ld defaults to for debugging > sections. > > > I also wonder, is this change fixing some existing bug, or it's just a > > cleanup change? > > If there were sections at 0, the resulting PE binary would end up broken. > Prior to binutils 2.37 this brokenness is silent, i.e. the linker doesn't > issue any form of diagnostic. The change therefore is addressing a latent > issue - if any such section started being non-empty, we'd be in trouble. > > > I also only see the .comment section in my binary output, so maybe > > it's fine to just remove them from the script? > > Which binary are you referring to - ELF or PE? In the former case, yes, > that's what the statement is for. In the latter case I can't see how this > would be, with .comment being explicitly part of /DISCARD/ in that case.
So from a bit of searching I just did it seems like stab sections where used during the 90s with ELF, but that this has long been superseded by DWARF 2 becoming the default in the late 90s, hence I think it would be fine to just remove those sections even in the ELF case? Thanks, Roger.
