* add the StaticInitCloner utility
* remove bridging of `copyStaticInitializer` and `createStaticInitializer`
* add `Context.mangleOutlinedVariable` and `Context.createGlobalVariable`
Introduces a set of protocols useful to perform def-use and use-def
traversals to find uses and definitions of values.
This logic was originally baked into `EscapeInfo` directly.
Here we extract it into general utilities, namely:
- `ValueDefUseWalker`: visit uses of a value walking down value-value projections/constructions.
- `AddressDefUseWalker`: visit uses of an address walking down addr-addr projections/constructions.
- `ValueUseDefWalker`: visit definitions of a value walking up value-value projections/constructions.
- `AddressUseDefWalker`: visit definitions of an address walking up addr-addr projections/constructions.
These utilities can then be used in other passes or to create
new utilities by composing them. For example to find a definition
passing through both address projections and value extractions,
it's enough to implement a visitor conforming to both
`AddressUseDefWalker` and `ValueUseDefWalker`.
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.
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.
