On Mon, Oct 18, 2021 at 11:02:20AM +0200, Jan Beulich wrote: > On 15.10.2021 18:58, Anthony PERARD wrote: > > On Thu, Oct 14, 2021 at 12:14:29PM +0200, Jan Beulich wrote: > >> On 24.08.2021 12:50, Anthony PERARD wrote: > >>> --- a/xen/Rules.mk > >>> +++ b/xen/Rules.mk > >>> @@ -38,7 +38,7 @@ SPECIAL_DATA_SECTIONS := rodata $(foreach a,1 2 4 8 16, > >>> \ > >>> $(foreach r,rel rel.ro,data.$(r).local) > >>> > >>> # The filename build.mk has precedence over Makefile > >>> -mk-dir := $(src) > >>> +mk-dir := $(srctree)/$(src) > >>> include $(if $(wildcard > >>> $(mk-dir)/build.mk),$(mk-dir)/build.mk,$(mk-dir)/Makefile) > >> > >> Perhaps already when it was changed to $(src) the name has become > >> slightly misleading, at least imo: I would rather expect a variable > >> with this name to refer to the build dir/tree. Maybe "srcdir" or > >> even shorted "sd" right from the start? (Reaching here I can finally > >> see why having a shorthand is helpful.) > > > > I have to think about that. I've made some further progress in order to > > be able to build the Xen pvhshim without a link farm and notice that > > nearly every source file needs to use "$(srctree)/$(src)" > > Oh, now I'm curious as to the why here. I thought use of $(srctree) > ought to be the exception.
In Linux, the use of $(srctree) is indeed the exception. This is because we have VPATH=$(srctree), so when `make` look for a prerequisite or a target it will look first in the current directory and then in $(srctree). That works fine as long as the source tree only have sources and no built files. But if we want to be able to build the pv-shim without the linkfarm and thus using out-of-tree build, we are going to need the ability to build from a non-clean source tree. I don't think another way is possible. This can be done by teaching make to only look for source file in $(srctree), and to look for generated/built file only in $(objtree). That's mostly done by not using VPATH and making few other adjustments. I hope my description of where I'm going isn't too convoluted. > > and I'm not > > sure "$(src)" could be use alone. So having a single variable which have > > both would be useful. > > > > "srcdir" might be to close to "srctree" and one might mistake it for the > > other, so "sd" might be better. > > While I did suggest "sd" as an option, already when writing this I > wasn't convinced this would be descriptive enough. Personally I think > "dir" and "tree" are sufficiently different names. I would suggest > "srcroot" for what is now "srctree", but that would have the > disadvantage of getting us out of sync with Linux. Ok, I guess "srcdir" is good. Thanks. -- Anthony PERARD
