[GR-77163] Safely publish object type id cache.#14006
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failing: Multi type state with single type.
It happened in bytecode-sensitive subtraction. That code builds result object arrays using a cached int[] of object type IDs from ContextSensitiveMultiTypeState.getObjectTypeIds(). The cache was lazily initialized and stored in a plain field. In parallel analysis, another worker thread could observe the array reference without a proper publication edge, so it was not guaranteed to see the filled array contents.
If stale/default type IDs were read, subtraction could keep/remove the wrong objects, then try to construct a MultiTypeState even though the resulting bitset had only one type, triggering the assertion.
Implemented change
I changed ContextSensitiveMultiTypeState.objectTypeIds to volatile.
That makes the lazy cache safely published: the thread that fills the array writes all elements first, then publishes the reference through a volatile write. Other threads reading the non-null volatile reference are guaranteed to see the initialized contents. No synchronization is needed because duplicate initialization is harmless and the array is not mutated after publication.
backport
This needs to be backported to 25.0.