[12/13] hash set: reject attempts to add empty values

[Alexandre Oliva via Gcc-patches]

Check, after adding a key to a hash set, that the entry does not look
empty.

Regstrapped on x86_64-linux-gnu.  Ok to install?


for  gcc/ChangeLog

        * hash-set.h (add): Check that the inserted entry does not
        look empty.
---
 gcc/hash-set.h |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gcc/hash-set.h b/gcc/hash-set.h
index 76fa7f394561e..a98121a060eed 100644
--- a/gcc/hash-set.h
+++ b/gcc/hash-set.h
@@ -58,7 +58,11 @@ public:
       Key *e = m_table.find_slot_with_hash (k, Traits::hash (k), INSERT);
       bool existed = !Traits::is_empty (*e);
       if (!existed)
-       new (e) Key (k);
+       {
+         new (e) Key (k);
+         // Catch attempts to insert e.g. a NULL pointer.
+         gcc_checking_assert (!Traits::is_empty (*e));
+       }
 
       return existed;
     }

-- 
Alexandre Oliva, happy hacker                https://FSFLA.org/blogs/lxo/
   Free Software Activist                       GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts.  Ask me about <https://stallmansupport.org>