SILGen: Fix setting variables with property wrappers marked objc dynamic

[aschwaighofer]

rdar://54181647

[aschwaighofer]

@swift-ci Please test

[slavapestov]

Can the setter be a class method or a witness method also

[aschwaighofer]

I don't think so, this code is for property wrapped vars.

This:

class SomeWrapperTests {
@SomeWrapper var someWrapper: Int = 0

will just emit a function ref.

I am guessing we treat this like stored properties.

[jrose-apple]

Property-wrapped vars should definitely be overridable in subclasses.

[aschwaighofer]

Hmm, then the code before this patch is broken:

 @propertyWrapper
 public struct SomeWrapper {
   private var value: Int

 
    public init(wrappedValue: Int) {
     value = wrappedValue
   }

 
    public var wrappedValue: Int {
     get { value }
     set { value = newValue }
   }
 }

SILGen will emit a direct function_ref and not a class_method call for the setter in the example below:

  class SomeWrapperTests {
   @SomeWrapper var someWrapper: Int = 0
   func testAssignment() {
     someWrapper = 1000
   }
 }

sil hidden [ossa] @$s7Wrapper04SomeA5TestsC14testAssignmentyyF : $@convention(method) (@guaranteed SomeWrapperTests) -> () {
// %0                                             // users: %12, %6, %1
bb0(%0 : @guaranteed $SomeWrapperTests):
  ...
  %9 = function_ref @$s7Wrapper04SomeA0V12wrappedValueACSi_tcfCTc : $@convention(thin) (@thin SomeWrapper.Type) -> @owned @callee_guaranteed (Int) -> SomeWrapper
  %10 = apply %9(%8) : $@convention(thin) (@thin SomeWrapper.Type) -> @owned @callee_guaranteed (Int) -> SomeWrapper
  // function_ref SomeWrapperTests.someWrapper.setter
  %11 = function_ref @$s7Wrapper04SomeA5TestsC04someA0Sivs : $@convention(method) (Int, @guaranteed SomeWrapperTests) -> ()
  %12 = copy_value %0 : $SomeWrapperTests
  %13 = partial_apply [callee_guaranteed] %11(%12) : $@convention(method) (Int, @guaranteed SomeWrapperTests) -> ()
  assign_by_wrapper %5 : $Int to %7 : $*SomeWrapper, init %10 : $@callee_guaranteed (Int) -> SomeWrapper, set %13 : $@callee_guaranteed (Int) -> ()
  end_access %7 : $*SomeWrapper 
 

[jrose-apple]

Yikes! We should fix that too, then. :-) I guess I'll file a separate Radar.

[jrose-apple]

Filed SR-11571, soon to be cloned.