Re: [PATCH v1 2/2] Strip build path directories in tools, xen and xen/arch/x86

["Anthony PERARD" <anthony.perard@vates.tech>]

On Thu, Mar 20, 2025 at 02:59:04PM +0100, Marek Marczykowski-Górecki wrote:
> On Thu, Mar 20, 2025 at 02:49:27PM +0100, Jan Beulich wrote:
> > On 20.03.2025 13:51, Marek Marczykowski-Górecki wrote:
> > > On Thu, Mar 20, 2025 at 10:18:28AM +0000, Anthony PERARD wrote:
> > >> On Wed, Mar 19, 2025 at 02:40:33PM +0100, Marek Marczykowski-Górecki wrote:
> > >>> There are clearly some build path embedding left. And
> > >>> -ffile-prefix-map=/-fdebug-prefix-map= doesn't work correctly with
> > >>> XEN_ROOT having xen/.. at the end.
> > >>> BTW, would it be acceptable to have this?
> > >>>
> > >>>     $(call cc-option-add,CFLAGS,CC,-fdebug-prefix-map=$(realpath $(XEN_ROOT))=.)
> > >>
> > >> Hi,
> > >>
> > >> Could you avoid using $(XEN_ROOT) in hypervisor build system? (It's fine
> > >> in "tools/"). In "xen/", there's a few variables you can use if they are
> > >> needed: $(abs_objtree) $(abs_srctree) for absolutes path, and $(srctree)
> > >> $(objtree) for relative path. That also should avoid the need to use
> > >> $(realpath ).
> > >
> > > XEN_ROOT is literally "$(abs_srctree)/..". And I need to resolve it to
> > > not have /.. for prefix-map to work correctly. Would it be better to use
> > > literal $(realpath $(abs_srctree)/..)? Or use just $(abs_srctree) and
> > > have paths in debug symbols relative to hypervisor source dir, instead
> > > of xen repo root? I'm not sure if that wouldn't confuse some tools...
> >
> > abs_srctree being computed using realpath, can't we replace
> >
> > export XEN_ROOT := $(abs_srctree)/..
> >
> > by something as simpl{e,istic} as
> >
> > export XEN_ROOT := $(patsubst %/xen,%,$(abs_srctree))
> >
> > ?
>
> That works too. It's slightly less robust, but I don't expect "xen"
> directory to be renamed, so shouldn't be an issue. I'll leave also a
> comment there why not /.. .

I don't think $(XEN_ROOT) is present in the binaries produce by the
hypervisor's build system. There's only a few use if that variable: to
load some makefile, to execute makefile that build xsm policy and to
generate cpuid-autogen.h. Otherwise I don't think the compile have this
path in the command line. What is going to be in the binary is
$(abs_srctree), which you can replace by "./xen" if you want; which mean
it doesn't matter if the directory is renamed or not. You might want to
also take care of $(abs_objtree) which seems to also be in `xen-syms`
when doing out-of-tree build.

Cheers,

--

Anthony Perard | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech