[PATCH] libdw: Make __libdw_dieabbrev more robust on failure.

[Mark Wielaard <mark@klomp.org>]

Make sure to always set die->abbrev to DWARF_END_ABBREV on failure.
DWARF_END_ABBREV is also what the function reports on failure. And it
will prevent trying to lookup the abbrev ever again.

Signed-off-by: Mark Wielaard <mark@klomp.org>
---
 libdw/ChangeLog | 5 +++++
 libdw/libdwP.h  | 5 +++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 07a1346b..78321654 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,8 @@
+2018-06-12  Mark Wielaard  <mark@klomp.org>
+
+	* libdw.h (__libdw_dieabbrev): Set die->abbrev to DWARF_END_ABBREV
+	on failure.
+
 2018-06-10  Mark Wielaard  <mark@klomp.org>
 
 	* dwarf_attr_integrate.c (dwarf_attr_integrate): Stop after 16 DIE
diff --git a/libdw/libdwP.h b/libdw/libdwP.h
index 3d8e145a..eebb7d12 100644
--- a/libdw/libdwP.h
+++ b/libdw/libdwP.h
@@ -653,8 +653,9 @@ __libdw_dieabbrev (Dwarf_Die *die, const unsigned char **readp)
       /* Get the abbreviation code.  */
       unsigned int code;
       const unsigned char *addr = die->addr;
-      if (die->cu == NULL || addr >= (const unsigned char *) die->cu->endp)
-	return DWARF_END_ABBREV;
+      if (unlikely (die->cu == NULL
+		    || addr >= (const unsigned char *) die->cu->endp))
+	return die->abbrev = DWARF_END_ABBREV;
       get_uleb128 (code, addr, die->cu->endp);
       if (readp != NULL)
 	*readp = addr;
-- 
2.17.0