[PATCH 4/4] libstdc++: Initialize all members of hashtable local iterators

[Jonathan Wakely]

Currently the _M_bucket members are left uninitialized for
default-initialized local iterators, and then copy construction copies
indeterminate values. We should just ensure they're initialized on
construction.

Setting them to zero makes default-initialization consistent with
value-initialization and avoids indeterminate values.

For the _Local_iterator_base<..., false> specialization we preserve the
existing behaviour of setting _M_bucket_count to -1 in the default
constructor, as a sentinel value to indicate there's no hash object
present.

libstdc++-v3/ChangeLog:

        * include/bits/hashtable_policy.h (_Local_iterator_base): Use
        default member-initializers.
---

Tested x86_64-linux.

 libstdc++-v3/include/bits/hashtable_policy.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/libstdc++-v3/include/bits/hashtable_policy.h 
b/libstdc++-v3/include/bits/hashtable_policy.h
index b7788eb5bd7..6f46a5796ba 100644
--- a/libstdc++-v3/include/bits/hashtable_policy.h
+++ b/libstdc++-v3/include/bits/hashtable_policy.h
@@ -1156,8 +1156,8 @@ namespace __detail
          }
       }
 
-      size_t _M_bucket;
-      size_t _M_bucket_count;
+      size_t _M_bucket = 0;
+      size_t _M_bucket_count = 0;
 
     public:
       size_t
@@ -1194,7 +1194,7 @@ namespace __detail
       using __hash_obj_storage = _Hash_obj_storage<_Hash>;
       using __node_iter_base = _Node_iterator_base<_Value, false>;
 
-      _Local_iterator_base() : _M_bucket_count(-1) { }
+      _Local_iterator_base() = default;
 
       _Local_iterator_base(const __hash_code_base& __base,
                           _Hash_node<_Value, false>* __p,
@@ -1242,8 +1242,8 @@ namespace __detail
          }
       }
 
-      size_t _M_bucket;
-      size_t _M_bucket_count;
+      size_t _M_bucket = 0;
+      size_t _M_bucket_count = -1;
 
       void
       _M_init(const _Hash& __h)
-- 
2.47.1