Guard the dereference in the case where the current cursor in the
needle isn't a tombstone in case we're at the end of the
haystack. Example pair:
NEEDLE: 6 x x 4 6
HAYSTACK: 4 6 x x 4
We find the subsequence 6 4, but the needle is not yet at end (missing
6) while the haystack is moved past the end:
NEEDLE: 6 x x 4 6
^
HAYSTACK: 4 6 x x 4
^
If the haystack (super) is exhausted before the needle (sub) we know
it isn't a proper subsequence, so this is the correct behaviour.
This example was in the testsuite and caught by ASAN.
PR gcov-profile/127038
gcc/ChangeLog:
* gcov.cc (tombstone_subsequence_p): Guard iterator
dereference.
---
gcc/gcov.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/gcov.cc b/gcc/gcov.cc
index 87deeadcc75..0ad48eb1b54 100644
--- a/gcc/gcov.cc
+++ b/gcc/gcov.cc
@@ -1015,7 +1015,7 @@ tombstone_subsequence_p (const vector<unsigned>& sub,
if (yitr == yend)
return false;
}
- else if (*yitr != *xitr)
+ else if (yitr == yend || *yitr != *xitr)
return false;
yitr = find_if_not (yitr, yend, tombstone_p);
--
2.47.3
