Reviewed by Darin Adler.
https://bugs.webkit.org/show_bug.cgi?id=34150
WebKit needs a mechanism to catch stale HashMap entries
It is very difficult to catch stale pointers that are HashMap keys - since a pointer's hash
is just its value, it is very unlikely that any observable problem is reproducible.
This extends hash table consistency checks to check that pointers are referencing allocated
memory blocks, and makes it possible to invoke the checks explicitly (it is not feasible
to enable CHECK_HASHTABLE_CONSISTENCY by default, because that affects performance too much).
* wtf/HashMap.h: (WTF::::checkConsistency): Call through to HashTable implementation. We can
add similar calls to HashSet and HashCountedSet, but I haven't seen hard to debug problems
with those yet.
* wtf/HashSet.h: (WTF::::remove): The version of checkTableConsistency that's guarded by
CHECK_HASHTABLE_CONSISTENCY is now called internalCheckTableConsistency().
* wtf/HashTable.h:
(WTF::HashTable::internalCheckTableConsistency):
(WTF::HashTable::internalCheckTableConsistencyExceptSize):
(WTF::HashTable::checkTableConsistencyExceptSize):
Expose checkTableConsistency() even if CHECK_HASHTABLE_CONSISTENCY is off.
(WTF::::add): Updated for checkTableConsistency renaming.
(WTF::::addPassingHashCode): Ditto.
(WTF::::removeAndInvalidate): Ditto.
(WTF::::remove): Ditto.
(WTF::::rehash): Ditto.
(WTF::::checkTableConsistency): The assertion for !shouldExpand() was not correct - this
function returns true for tables with m_table == 0.
(WTF::::checkTableConsistencyExceptSize): Call checkValueConsistency for key. Potentially,
we could do the same for values.
* wtf/HashTraits.h:
(WTF::GenericHashTraits::checkValueConsistency): An empty function that can be overridden
to add checks. Currently, the only override is for pointer hashes.
* wtf/RefPtrHashMap.h: (WTF::::remove): Updated for checkTableConsistency renaming.
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@53957 268f45cc-cd09-0410-ab3c-d52691b4dbfc
20 files changed
