void ArrayAllocationProfile::updateIndexingType()
{
// This is awkwardly racy but totally sound even when executed concurrently. The
// worst cases go something like this:
//
// - Two threads race to execute this code; one of them succeeds in updating the
// m_currentIndexingType and the other either updates it again, or sees a null
// m_lastArray; if it updates it again then at worst it will cause the profile
// to "forget" some array. That's still sound, since we don't promise that
// this profile is a reflection of any kind of truth.
//
// - A concurrent thread reads m_lastArray, but that array is now dead. While
// it's possible for that array to no longer be reachable, it cannot actually
// be freed, since we require the GC to wait until all concurrent JITing
// finishes.
JSArray* lastArray = m_lastArray;
if (!lastArray)
return;
m_currentIndexingType = leastUpperBoundOfIndexingTypes(m_currentIndexingType, lastArray->structure()->indexingType());
m_lastArray = 0;
}
IndexingType leastUpperBoundOfIndexingTypeAndValue(IndexingType indexingType, JSValue value)
{
return leastUpperBoundOfIndexingTypes(indexingType, indexingTypeForValue(value) | (indexingType & IsArray));
}
