Re: [PATCH] Fail if dwz fails.

[Mark Wielaard <mark@klomp.org>]

Hi Martin,

On Fri, May 14, 2021 at 12:46:15PM +0200, Martin Liška wrote:
> On 5/13/21 4:07 PM, Mark Wielaard wrote:
> > > On 4/22/21 1:11 PM, Martin Liška wrote:
> > > > Right now, dwz return code is 0 or a small integer value (<= 3)
> > > > for situations like:
> > > > 
> > > > - dwz: Too few files for multifile optimization
> > > > - dwz: Multi-file optimization not allowed for different pointer sizes or endianity
> > > > 
> > > > These are not fatal errors and the script should continue. On the other
> > > > hand abort or segfault error values should cause failure of the script.
> > > > 
> > > > Let's reserve values 1-16 for a recoverable dwz exit codes.
> > 
> > With "recoverable" you mean that dwz did do compression, but could not
> > deliver optimal compression?
> 
> No, I speak about cases, where compression cannot be done
> (different endianess, ptr sizes, not beneficial, any other reason).

I think we are talking about somewhat the same thing. In those cases
dwz does something. The result is just not optimal.

> > It would be good to have an ack from the dwz developers that 1 to 16
> > are "recoverable" errors (I added dwz@sourceware.org to CC).
> 
> Yes. That's why I CCed Tom.
> 
> > 
> > Would it be possible to tweak the find-debuginfo.sh script to avoid
> > them? e.g. Could we see how many arguments we have so that we only use
> > -m when there are 1+ debug files? And/Or detect debug files using
> > different endianess and ptr sizes so they are processed in different
> > batches?
> 
> No, I would leave it to dwz. There may be other reasons.

But for the reasons we do know about we could improve
find-debuginfo.sh to do the right thing (not use -m if there is only
one file, sort files by endianess/ptrsize). Ideally you call
find-debuginfo.sh and it does the right thing even if you only have
one ELF file or a mix of ELF files.

> > Ideally an error code from dwz means something went terribly wrong and
> > we abort find-debuginfo.sh. IMHO.
> 
> I would allow the mentioned "soft" error codes.

Couldn't optimize is an "soft" error indeed. I don't know about the
others.

Cheers,

Mark