Re: [PATCH] Incremental merge for ppc-vx6

[Alan Modra <amodra at gmail dot com>]

On Mon, Oct 22, 2018 at 12:09:38PM -0700, Douglas B Rupp wrote:
> 
> This patch implements merging of sections created by -ffunction-sections and
> -fdata-sections on ppc-vx6.

Which means you are breaking ld --gc-sections if you use ld -r in any
intermediate step on the way to link a final executable.  It's bad
enough that ld -r merges sections of like names, let alone merging
.text.* into .text.

> If the sections are not merged, gdb malfunctions when printing the address
> of a runtime symbol.

Presumably you are talking about a gdb problem only when trying to
debug kernel modules or similar objects that haven't undergone a final
link.  If address are a problem, have you considered modifying ld -r
to instead not set section VMAs to zero?  That would mean removing all
${RELOCATING-0} from elf.sc and modifying lang_insert_orphan to not
use "address = exp_intop (0)" for ld -r.  If that cures the vxworks
gdb problem, I'd much rather remove a hack from GNU ld for Solaris
than add a new hack for vxworks.

> The problem can be fixed in gdb (but not easily) for the WTX protocol used
> for older vxworks targets but not for newer vxworks (e.g. vxworks7) because
> the protocol is different and not under gdb control.

I find it hard to believe a host/target communication protocol has any
bearing on this problem.

-- 
Alan Modra
Australia Development Lab, IBM