swift234

In -enable-top-level-definite-init mode, emit a "mark_function_escape" instruction
for func decls that capture globals defined in the current file.  For example, for:

var x : Int

func foo() {
  print(x)
}

x = 15

We now silgen to:

sil internal @top_level_code : $() -> () {
bb0:
  %0 = global_addr #x : $*Int64                   // user: %1
  %1 = mark_uninitialized %0 : $*Int64            // users: %7, %2
  mark_function_escape %1 : $*Int64
  // function_ref swift.Int64._convertFromBuiltinIntegerLiteral (swift.Int64.metatype)(val : Builtin.Int128) -> swift.Int64
  %3 = function_ref @_TSi33_convertFromBuiltinIntegerLiteralfMSiFT3valBi128__Si : $[thin] ((val : Builtin.Int128), Int64.metatype) -> Int64 // user: %6
  %4 = metatype $Int64.metatype                   // user: %6
  %5 = integer_literal $Builtin.Int128, 15        // user: %6
  %6 = apply [transparent] %3(%5, %4) : $[thin] ((val : Builtin.Int128), Int64.metatype) -> Int64 // user: %7
  assign %6 to %1 : $*Int64
  %8 = tuple ()                                   // user: %9
  return %8 : $()
}

which will allow definite initialization to diagnose the error.

Note that we don't currently handle uses in constructors, like:

class frank {
  constructor() {
    print(x)
  }
}

... because the capture list is only stored for FuncDecls, not for AbstractFunction's.  It should be hoisted up at some point.




Swift SVN r8188