x86/mm: override stored file names for multiply built sources

To make it possible to tell apart the static symbols therein, use their
object file names instead of their source ones.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/mm/guest_walk.c
+++ b/xen/arch/x86/mm/guest_walk.c
@@ -29,6 +29,8 @@
 #include <asm/page.h>
 #include <asm/guest_pt.h>
 
+/* Allow uniquely identifying static symbols in the 3 generated objects. */
+asm(".file \"guest_walk_" __stringify(GUEST_PAGING_LEVELS) ".o\"");
 
 /* Flags that are needed in a pagetable entry, with the sense of NX inverted */
 static uint32_t mandatory_flags(struct vcpu *v, uint32_t pfec) 
--- a/xen/arch/x86/mm/hap/guest_walk.c
+++ b/xen/arch/x86/mm/hap/guest_walk.c
@@ -38,6 +38,9 @@
 #include <asm/guest_pt.h>
 #include <asm/p2m.h>
 
+/* Allow uniquely identifying static symbols in the 3 generated objects. */
+asm(".file \"guest_walk_" __stringify(GUEST_PAGING_LEVELS) "level.o\"");
+
 unsigned long hap_gva_to_gfn(GUEST_PAGING_LEVELS)(
     struct vcpu *v, struct p2m_domain *p2m, unsigned long gva, uint32_t *pfec)
 {
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -41,6 +41,9 @@
 #include "private.h"
 #include "types.h"
 
+/* Allow uniquely identifying static symbols in the 3 generated objects. */
+asm(".file \"guest_" __stringify(GUEST_PAGING_LEVELS) ".o\"");
+
 /* THINGS TO DO LATER:
  *
  * TEARDOWN HEURISTICS