[K/N] Change AtomicReference for the new MM ^KT-50026

Make AtomicReference behave like FreezableAtomicReference with the new MM: not frozen by default, don't require freezing value unless the ref itself is frozen. The behaviour with the old MM is unchanged.

Merge-request: KT-MR-5155

kotlin-native/runtime/src/main/kotlin/kotlin/native/concurrent/Atomics.kt

@@ -215,7 +215,7 @@ private fun debugString(value: Any?): String {
  * Otherwise memory leak could happen. To detect such leaks [kotlin.native.internal.GC.detectCycles]
  * in debug mode could be helpful.
  */
-@Frozen
+@FrozenLegacyMM
 @LeakDetectorCandidate
 @NoReorderFields
 public class AtomicReference<T> {
@@ -232,7 +232,9 @@ public class AtomicReference<T> {
      * @throws InvalidMutabilityException if reference is not frozen.
      */
     constructor(value: T) {
-        checkIfFrozen(value)
+        if (this.isFrozen) {
+            checkIfFrozen(value)
+        }
         value_ = value
     }
 

kotlin-native/runtime/src/main/kotlin/kotlin/native/internal/Annotations.kt

@@ -48,6 +48,13 @@ public annotation class ExportForCompiler
 @Retention(AnnotationRetention.BINARY)
 internal annotation class Frozen
 
+/**
+ * Similar to `@Frozen`, but works only for legacy MM. On the new MM this has no effect.
+ */
+@Target(AnnotationTarget.CLASS)
+@Retention(AnnotationRetention.BINARY)
+internal annotation class FrozenLegacyMM
+
 /**
  * Fields of annotated class won't be sorted.
  */