JVM_IR: optimize delegation by property references

E.g. a statement like

    var x by ::y

is semantically equivalent to

    var x
      get() = y
      set(value) { y = value }

and thus does not need a full property reference object, or even a field
if the receiver is not bound.

 #KT-39054 Fixed
 #KT-47102 Fixed
This commit is contained in:
pyos
2021-06-16 13:22:32 +02:00
committed by Alexander Udalov
parent 66e052b9b3
commit e49410e07b
17 changed files with 286 additions and 2 deletions
@@ -0,0 +1,26 @@
// TARGET_BACKEND: JVM
// v-- fir2ir produces an IrFunctionReference of type KProperty0 instead of an IrPropertyReference
// IGNORE_BACKEND_FIR: JVM_IR
// WITH_REFLECT
// WITH_RUNTIME
// FILE: J.java
public interface J<T> {
public T getValue();
}
// FILE: box.kt
class Impl(val x: String) : J<String> {
override fun getValue() = x
}
val j1: J<String> = Impl("O")
// Note that taking a reference to `J<T>::value` is not permitted by the frontend
// in any context except as a direct argument to `by`; e.g. `val x by run { j1::value }`
// would produce an error.
val x by j1::value
fun box(): String {
val j2: J<String> = Impl("K")
val y by j2::value
return x + y
}