743865 - Allow HashMaps with non-default-constructible keys

Status: NEW

(Core :: JavaScript Engine, defect)

Description

[Jason Orendorff [:jorendorff]]

Currently js::HashMap<K, V, ...> requires K and V to be default-constructible, but I think this is only because js::detail::HashTableEntry contains these methods:

    void setFree()                { keyHash = sFreeKey; t = T(); }
    void setRemoved()             { keyHash = sRemovedKey; t = T(); }

HashTableEntry would have to be rewritten to call t's destructor
when changing state from live to free or removed.

As a prerequisite, we would need to JS_ASSERT(found()) in these methods of HashTable::Ptr:

        T &operator*() const                  { return entry->t; }
        T *operator->() const                 { return &entry->t; }