swift234

SILGen: Lower some builtins to SIL.

The value semantics primitives load/move/assign/init/destroy lower trivially to SIL value semantics operators, and the bridge casting operations introduce r/r semantics that should be visible to the ARC optimizer, so move the lowering for these builtins up to SILGen. Add a BUILTIN_SIL_OPERATION metaprogramming macro to Builtins.def, and add a facility similar to IRGen's former SpecializedCallEmission so we can handle builtin call emissions as special cases.

This also sets up the framework for eventually reintroducing special-case handling of known functions like &&, ||, Bool.getLogicValue, Int.convertFromIntegerLiteral, etc. in SILGen.

Swift SVN r4862