On Tue, Mar 04, 2025 at 11:33:44AM +0000, Alex Bennée wrote: > Daniel P. Berrangé <berra...@redhat.com> writes: > > > On Mon, Mar 03, 2025 at 10:17:03PM +0000, Alex Bennée wrote: > >> This option is supported by both gcc (since 4.7) and clang (since > >> 7.0). Not only does this make the linkers job easier by reducing the > >> amount of ELF it needs to parse it also reduces the total build size > >> quite considerably. In my case a default build went from 5.8G to 3.9G. > > > > I've not come across this option before, but the docs say > > > > ‘-gsplit-dwarf’ > > If DWARF debugging information is enabled, separate as much > > debugging information as possible into a separate output file with > > the extension ‘.dwo’. This option allows the build system to avoid > > linking files with debug information. To be useful, this option > > requires a debugger capable of reading ‘.dwo’ files. > > > > In Fedora and RHEL we build QEMU will full debug enabled, and then a feature > > of the distro RPM build config will post-process all ELF files to extract > > the debug info into files that we store under /usr/lib/debug. eg for > > /usr/bin/qemu-system-x86_64, we get a separate > > /usr/lib/debug/bin/qemu-system-x86_64-9.1.3-1.fc41.x86_64.debug, and > > tools like GDB, etc know to look for these separate files. > > A modern gdb can certainly handle fetching the debug out of the .dwo > files when debugging.
See this response from one of the upstream GCC maintainers pretty much recommending against (on by default) use of -gsplit-dwarf: https://lists.fedoraproject.org/archives/list/de...@lists.fedoraproject.org/thread/RXA55BTO62NWWHCTUFYGEVHJKZPL5EKE/ With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
