swift234

SILGen: Allow global variable accesses.
If an lvalue DeclRefExpr doesn't have a local VarLocs entry in the current SILGen function, assume it's a global variable and generate a constant_ref to get at its address. Eventually there should be a SILGenModule with which we can check that the global access is valid. Either ConstantRef should be renamed or a new GlobalVarRef instruction should be added as well.

Swift SVN r3319