Re: [XEN PATCH v7 10/51] build,arm: move LDFLAGS change to arch.mk

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Tue, Aug 24, 2021 at 01:50:33PM +0100, Julien Grall wrote:
> Hi Anthony,
> 
> Can you explain why this is moved?

Well, it was in the wrong place, it is best to avoid making changes to
XEN_CFLAGS or XEN_LDFLAGS in Makefile in subdirectories as those are
exported variable and may not work as expected. They may or may not
change *flags in subdirectories, or in the case of arch/*/Makefile, they
might changes *flags in the other directories or not depending on
whether one try to build "xen" or just "common/".

But more importantly, with patch
    build: set ALL_OBJS to main Makefile; move prelink.o to main Makefile
make isn't going to load arch/*/Makefile before building the rest of
xen, and thus changes to XEN_LDFLAGS will only apply to arch/*/Makefile
rather than for all objects. (XEN_LDFLAGS is used with all built_in.o
and few other places like for libfdt-temp.o)

If you want an explanation in the commit message, maybe this one will
do:
    Changes to XEN_LDFLAGS may or may not apply to targets in for
    example "common/" depending on whether one runs `make` or `make
    common/`.

    But arch.mk is loaded before doing any build, so changes to LDFLAGS
    there mean that the value of XEN_LDFLAGS won't depends on the
    initial target.

Thanks,

-- 
Anthony PERARD