Add atomic references.

backend.native/tests/build.gradle

@@ -673,7 +673,7 @@ task freeze2(type: RunKonanTest) {
 
 task atomic0(type: RunKonanTest) {
     disabled = (project.testTarget == 'wasm32') // Workers need pthreads.
-    goldValue = "35\n" + "0\n1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12\n13\n14\n15\n16\n17\n18\n19\n20\n"
+    goldValue = "35\n" + "20\n"
     source = "runtime/workers/atomic0.kt"
 }
 

backend.native/tests/runtime/workers/atomic0.kt

@@ -19,17 +19,57 @@ fun test1(workers: Array<Worker>) {
 
 fun test2(workers: Array<Worker>) {
     val atomic = AtomicInt(0)
+    val counter = AtomicInt(0)
     val futures = Array(workers.size, { workerIndex ->
-        workers[workerIndex].schedule(TransferMode.CHECKED, { atomic to workerIndex }) {
-            (place, index) ->
+        workers[workerIndex].schedule(TransferMode.CHECKED, { Triple(atomic, workerIndex, counter) }) {
+            (place, index, result) ->
             while (place.compareAndSwap(index, index + 1) != index) {}
-            println(index)
+            result.increment() == index + 1
+        }
+    })
+    futures.forEach {
+        assertEquals(it.result(), true)
+    }
+    println(counter.get())
+}
+
+data class Data(val value: Int)
+
+fun test3(workers: Array<Worker>) {
+    val common = AtomicReference<Data>()
+    val futures = Array(workers.size, { workerIndex ->
+        workers[workerIndex].schedule(TransferMode.CHECKED, { Pair(common, workerIndex) }) {
+            (place, index) ->
+            val mine = Data(index).freeze()
+            // Try to publish our own data, until successful, in a tight loop.
+            while (place.compareAndSwap(null, mine) != null) {}
         }
     })
+    val seen = mutableSetOf<Data>()
+    for (i in 0 until workers.size) {
+        do {
+            val current = common.get()
+            if (current != null && !seen.contains(current)) {
+                seen += current
+                // Let others publish.
+                assertEquals(common.compareAndSwap(current, null), current)
+                break
+            }
+        } while (true)
+    }
     futures.forEach {
         it.result()
     }
-    println(atomic.get())
+    assertEquals(seen.size, workers.size)
+}
+
+fun test4() {
+    assertFailsWith<InvalidMutabilityException> {
+        AtomicReference(Data(1))
+    }
+    assertFailsWith<InvalidMutabilityException> {
+        AtomicReference<Data>().compareAndSwap(null, Data(2))
+    }
 }
 
 @Test fun runTest() {
@@ -38,4 +78,6 @@ fun test2(workers: Array<Worker>) {
 
     test1(workers)
     test2(workers)
+    test3(workers)
+    test4()
 }

runtime/src/main/cpp/Atomic.cpp

@@ -15,6 +15,7 @@
  */
 
 #include "Atomic.h"
+#include "Common.h"
 #include "Types.h"
 
 namespace {
@@ -33,6 +34,8 @@ template <typename T> T compareAndSwapImpl(KRef thiz, T expectedValue, T newValu
 
 extern "C" {
 
+RUNTIME_NORETURN void ThrowInvalidMutabilityException();
+
 KInt Kotlin_AtomicInt_addAndGet(KRef thiz, KInt delta) {
     return addAndGetImpl(thiz, delta);
 }
@@ -53,4 +56,15 @@ KNativePtr Kotlin_AtomicNativePtr_compareAndSwap(KRef thiz, KNativePtr expectedV
     return compareAndSwapImpl(thiz, expectedValue, newValue);
 }
 
+void Kotlin_AtomicReference_checkIfFrozen(KRef value) {
+    if (value != nullptr && !value->container()->permanentOrFrozen()) {
+        ThrowInvalidMutabilityException();
+    }
+}
+
+KRef Kotlin_AtomicReference_compareAndSwap(KRef thiz, KRef expectedValue, KRef newValue) {
+    Kotlin_AtomicReference_checkIfFrozen(newValue);
+    return compareAndSwapImpl(thiz, expectedValue, newValue);
+}
+
 }  // extern "C"

runtime/src/main/kotlin/konan/worker/Atomics.kt

@@ -178,4 +178,32 @@ class AtomicNativePtr(private var value: NativePtr) {
      * Returns the current value.
      */
     fun get(): NativePtr = value
+}
+
+@SymbolName("Kotlin_AtomicReference_checkIfFrozen")
+external private fun checkIfFrozen(ref: Any?)
+
+@Frozen
+class AtomicReference<T>(private var value: T? = null) {
+    /**
+     * Creates a new atomic reference pointing to given [ref]. If reference is not frozen,
+     * @InvalidMutabilityException is thrown.
+     */
+    init {
+        checkIfFrozen(value)
+    }
+
+    /**
+     * Compares value with [expected] and replaces it with [new] value if values matches.
+     * If [new] value is not null, it must be frozen or permanent object, otherwise an
+     * @InvalidMutabilityException is thrown.
+     * Returns the old value.
+     */
+    @SymbolName("Kotlin_AtomicReference_compareAndSwap")
+    external fun compareAndSwap(expected: T?, new: T?): T?
+
+    /**
+     * Returns the current value.
+     */
+    public fun get(): T? = value
 }