Re: [PATCH] configure: disable split_debug on Windows and on non-git builds

["Daniel P. Berrangé" <berrange@redhat.com>]

On Fri, Mar 14, 2025 at 04:44:01PM +0000, Peter Maydell wrote:
> On Fri, 14 Mar 2025 at 15:39, Paolo Bonzini <pbonzini@redhat.com> wrote:
> >
> > -gsplit-dwarf is reported to produce broken binaries on Windows.
> > The linker produces warnings but exits successfully:
> >
> > /usr/lib/gcc/x86_64-w64-mingw32/14.2.0/../../../../x86_64-w64-mingw32/bin/ld:
> > qga/qemu-ga.exe:/4: section below image base
> > /usr/lib/gcc/x86_64-w64-mingw32/14.2.0/../../../../x86_64-w64-mingw32/bin/ld:
> > qga/qemu-ga.exe:/24: section below image base
> >
> > and as a result qemu-ga.exe fails to start.
> >
> > On top of this, also disable -gsplit-dwarf unless building from git.
> > Similar to -Werror, split debug info is probably not the best choice
> > for people that want to build for installing.
> >
> > (Random thoughts: there is a tension here between adding an option
> > that is useful for QEMU developers, and messing things up for everyone
> > else by doing something decidedly non-standard.  For example, distros
> > are starting to create a fake git repository just so that they can
> > use "git am" to apply patches; while some of them, for example Fedora,
> > are wise, or paranoid, enough to pass --disable-XXX for everything and
> > then turn back on what they want, it cannot be expected that everyone
> > does this.  It may be safer to make --enable-split-debug default off
> > for everybody and add it somewhere in docs/.  For now I am keeping it
> > enabled but we could consider doing something different during the hard
> > freeze period).
> >
> > Reported-by: Konstantin Kostiuk <kkostiuk@redhat.com>
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> > ---
> >  configure         | 4 ++++
> >  meson_options.txt | 2 +-
> >  2 files changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/configure b/configure
> > index 02f1dd2311f..9aece67ed08 100755
> > --- a/configure
> > +++ b/configure
> > @@ -1864,6 +1864,10 @@ if test "$skip_meson" = no; then
> >        { test "$host_os" = linux || test "$host_os" = "windows"; }; then
> >        echo 'werror = true' >> $cross
> >    fi
> > +  if test -e "$source_path/.git" && test "$host_os" != "windows"; then
> > +      echo 'split_debug = true' >> $cross
> > +  fi
> 
> Same remark as on the other patch: can we have a comment
> explaining why we disable this on Windows, please, ideally
> with a URL of a bug report against the toolchain ?

Two likely candidates open a long time....

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59474
  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99973


With regards,
Daniel
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