Andrew Trick f6624e355a Add EscapeAnalysis::findObjectKind to mitigate deinit side effects ...

Deinitializer side effects severely handicap the connection-graph
based EscapeAnalysis. Because it's not flow-sensitive, this approach
falls apart whenever an object is released in the current function,
which makes it seem to have escaped everywhere (it generally doesn't
matter if it doesn't escape until the release point, but the analysis
can't discern that).

This can be slightly mitigated by realizing that releasing an object
can only cause things it points to to escape if the object itself has
references or pointers.

Fix: Don't create a escaping content node when releasing an object
that can't contain any references or pointers.  The previous commit,
"Fix EscapeAnalysis::mayReleaseContent" would defeat release-hoisting
in important cases without doing anything else. Adding this extra
precision to the connection graph avoids some regressions.

2021-02-19 12:35:11 -08:00

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