[committed] Add first_dup macro

[Tom de Vries <tdevries@suse.de>]

Hi,

Committed to trunk.

Thanks,
- Tom

Add first_dup macro

2019-04-09  Tom de Vries  <tdevries@suse.de>

	* dwz.c (first_dup): New macro.

---
 dwz.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/dwz.c b/dwz.c
index eb97feb..8ea7c4d 100644
--- a/dwz.c
+++ b/dwz.c
@@ -794,6 +794,15 @@ die_cu (dw_die_ref die)
   return (dw_cu_ref) die->die_parent;
 }
 
+/* Given a toplevel die DIE, return the first (that is, the reference die) in
+   the duplicate chain.  */
+#define first_dup(die)				\
+  (die->die_dup					\
+   ? die->die_dup				\
+   : (die->die_nextdup				\
+      ? die					\
+      : NULL))
+
 /* Safe variant that check die_toplevel.  Can't be used on LHS.  */
 #define die_safe_dup(die) \
   ((die)->die_toplevel ? (die)->die_dup : (dw_die_ref) NULL)