[xen master] build: make FILE symbol paths consistent

[patchbot@xxxxxxx]

commit 5b9bb91abba7c983def3b4bef71ab08ad360a242
Author:     Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
AuthorDate: Wed Feb 15 16:13:49 2023 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Feb 15 16:13:49 2023 +0100

    build: make FILE symbol paths consistent
    
    The FILE symbols in out-of-tree builds may be either a relative path to
    the object dir or an absolute path depending on how the build is
    invoked. Fix the paths for C files so that they are consistent with
    in-tree builds - the path is relative to the "xen" directory (e.g.
    common/irq.c).
    
    This fixes livepatch builds when the original Xen build was out-of-tree
    since livepatch-build always does in-tree builds. Note that this doesn't
    fix the behaviour for Clang < 6 which always embeds full paths.
    
    Fixes: 7115fa562fe7 ("build: adding out-of-tree support to the xen build")
    Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/Rules.mk | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/Rules.mk b/xen/Rules.mk
index 70b7489ea8..d6b7cec0a8 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -228,8 +228,9 @@ quiet_cmd_cc_o_c = CC      $@
 ifeq ($(CONFIG_ENFORCE_UNIQUE_SYMBOLS),y)
     cmd_cc_o_c = $(CC) $(c_flags) -c $< -o $(dot-target).tmp -MQ $@
     ifneq ($(CONFIG_CC_IS_CLANG)$(call clang-ifversion,-lt,600,y),yy)
+        rel-path = $(patsubst $(abs_srctree)/%,%,$(call realpath,$(1)))
         cmd_objcopy_fix_sym = \
-           $(OBJCOPY) --redefine-sym $(<F)=$< $(dot-target).tmp $@ && rm -f 
$(dot-target).tmp
+           $(OBJCOPY) --redefine-sym $(<F)=$(call rel-path,$<) 
$(dot-target).tmp $@ && rm -f $(dot-target).tmp
     else
         cmd_objcopy_fix_sym = mv -f $(dot-target).tmp $@
     endif
--
generated by git-patchbot for /home/xen/git/xen.git#master