swift234

SILGen: Implement recursive local function references.

Instead of immediately creating closures for local function declarations and treating them directly as capturable values, break function captures down and transitively capture the storage necessary to invoke the captured functions. Change the way SILGen emits calls to closures and local functions so that it treats the capture list as the first curry level of an invocation, so that full applications of closure literals or nested functions don't require a partial apply at all. This allows references among local functions with captures to work within the existing confines of partial_apply, and also has the nice benefit that circular references would work without creating reference cycles (though Sema unfortunately rejects them; something we arguably ought to fix.)

This fixes rdar://problem/11266246 and improves codegen of local functions. Full applications of functions, or immediate applications of closure literals like { }(), now never need to allocate a closure.

Swift SVN r28112