Re: [PATCH 2/2] xen: Add CONFIG_GC_SECTIONS

[Anthony PERARD <anthony@xenproject.org>]

On Tue, Dec 09, 2025 at 04:47:28PM -0500, Jason Andryuk wrote:
> diff --git a/xen/Makefile b/xen/Makefile
> index e6cf287425..aeb5dcf2ee 100644
> --- a/xen/Makefile
> +++ b/xen/Makefile
> @@ -469,10 +469,13 @@ all-symbols-$(CONFIG_FAST_SYMBOL_LOOKUP) += --sort-by-name
>  
>  include $(srctree)/arch/$(SRCARCH)/arch.mk
>  
> +XEN_FINAL_LDFLAGS-$(CONFIG_GC_SECTIONS) := --gc-sections

Is there a good reason to add this flags after the arch-specific
makefiles? If not, could you move that just before, and right after the
definition of "$(all-symbols)" as it's a variable that is used in the
same phase of the build. (With Jan's other feedback)

>  # define new variables to avoid the ones defined in Config.mk
>  export XEN_CFLAGS := $(CFLAGS)
>  export XEN_AFLAGS := $(AFLAGS)
>  export XEN_LDFLAGS := $(LDFLAGS)
> +export XEN_FINAL_LDFLAGS := $(LDFLAGS) $(XEN_FINAL_LDFLAGS-y)

"FINAL" isn't very descriptive. A completely wrong interpretation might
be that we should use the "final" variable instead of "XEN_LDFLAGS". How
about a name that describe where this set of flags is going to be used,
like "XEN_LDFLAGS_xen_syms" (which unfortunately doesn't exactly fit
with x86 xen.efi target), or maybe suffix it with "_target" or just
"_xen"? (In Linux build system, they use "LDFLAGS_vmlinux", but I don't
know what would be the equivalent of "vmlinux" in our build system.)

The prefix "XEN_" is used as namespace, with one reason described in the
comment.

Also, could you use $(XEN_LDFLAGS) instead of $(LDFLAGS) ?

Cheers,

-- 
Anthony PERARD