swift

9dc3bd6e - Swift Optimizer: add `EscapeInfo`, a new utility for escape analysis

Swift Optimizer: add `EscapeInfo`, a new utility for escape analysis It’s a replacement for the old `EscapeAnalysis`, implemented in Swift (instead of C++) and with a much simple design and implementation. While the old EscapeAnalysis builds a connection graph, the new EscapeInfo just performs a simple def-use and use-def walk in the SIL. The EscapeInfo does not need to analyze the whole function (like the EscapeAnalysis does), but just the relevant value which is inspected. Therefore EscapeInfo is not an `Analysis` which caches its result across optimization passes - it’s not needed.