[PATCH 1/9] build: use if_changed more consistently (and correctly) for prelink*.o

[Jan Beulich <jbeulich@xxxxxxxx>]

Switch to $(call if_changed,ld) where possible; presumably not doing so
in e321576f4047 ("xen/build: start using if_changed") right away was an
oversight, as it did for Arm in (just) one case. It failed to add
prelink.o to $(targets), though, causing - judging from the observed
behavior on x86 - undue rebuilds of the final binary (because of
prelink.o getting rebuild for $(cmd_prelink.o) being empty, in turn
because of .prelink.o.cmd not getting read) during "make install-xen".

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/arm/Makefile |  4 +++-
 xen/arch/x86/Makefile | 18 ++++++++++--------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 51173d97127e..296c5e68bbc3 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -95,12 +95,14 @@ prelink_lto.o: $(ALL_OBJS)
 
 # Link it with all the binary objects
 prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o
-       $(LD) $(XEN_LDFLAGS) -r -o $@ $^
+       $(call if_changed,ld)
 else
 prelink.o: $(ALL_OBJS) FORCE
        $(call if_changed,ld)
 endif
 
+targets += prelink.o
+
 $(TARGET)-syms: prelink.o xen.lds
        $(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o \
            $(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 74152f2a0dad..9b368632fb43 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -136,19 +136,21 @@ prelink_lto.o: $(ALL_OBJS)
        $(LD_LTO) -r -o $@ $^
 
 # Link it with all the binary objects
-prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o 
$(EFI_OBJS-y)
-       $(LD) $(XEN_LDFLAGS) -r -o $@ $^
+prelink.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) prelink_lto.o 
$(EFI_OBJS-y) FORCE
+       $(call if_changed,ld)
 
-prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) 
prelink_lto.o
-       $(LD) $(XEN_LDFLAGS) -r -o $@ $^
+prelink-efi.o: $(patsubst %/built_in.o,%/built_in_bin.o,$(ALL_OBJS)) 
prelink_lto.o FORCE
+       $(call if_changed,ld)
 else
-prelink.o: $(ALL_OBJS) $(EFI_OBJS-y)
-       $(LD) $(XEN_LDFLAGS) -r -o $@ $^
+prelink.o: $(ALL_OBJS) $(EFI_OBJS-y) FORCE
+       $(call if_changed,ld)
 
-prelink-efi.o: $(ALL_OBJS)
-       $(LD) $(XEN_LDFLAGS) -r -o $@ $^
+prelink-efi.o: $(ALL_OBJS) FORCE
+       $(call if_changed,ld)
 endif
 
+targets += prelink.o prelink-efi.o
+
 $(TARGET)-syms: prelink.o xen.lds
        $(LD) $(XEN_LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
            $(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
-- 
2.22.0