Mike Ash fbc3f69ebf [RemoteMirror] Fix demangle node corruption caused by excessively eager clearing of the NodeFactory. ...

We clear the NodeFactory to prevent unbounded buildup of allocated memory, but this is done too eagerly. In particular, normalizeReflectionName can end up clearing the factory while the calling code is still using nodes that were allocated from it.

To keep peak memory usage low while avoiding this problem, we introduce a checkpoint mechanism in NodeFactory. A checkpoint can be pushed and then subsequently popped. When a checkpoint is popped, only the nodes allocated since the checkpoint was pushed are invalidated and the memory reclaimed. This allows us to quickly clear short-lived nodes like those created in normalizeReflectionName, while preserving longer-lived nodes used in code calling it. Uses of clearNodeFactory are replaced with this checkpoint mechanism.

rdar://106547092

2023-03-29 16:59:21 -04:00

22 KiB

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