Fix Arm32 atomics

kotlin-native/konan/konan.properties

@@ -770,7 +770,7 @@ clangNooptFlags.android_arm32 = -O1
 targetSysRoot.android_arm32 = target-sysroot-1-android_ndk
 linkerKonanFlags.android_arm32 = -lm -lc++_static -lc++abi -landroid -llog -latomic
 runtimeDefinitions.android_arm32 = __ANDROID__ USE_GCC_UNWIND=1 USE_ELF_SYMBOLS=1 ELFSIZE=32 \
-  KONAN_ANDROID=1 KONAN_ARM32=1 KONAN_NO_UNALIGNED_ACCESS=1
+  KONAN_ANDROID=1 KONAN_ARM32=1 KONAN_NO_UNALIGNED_ACCESS=1 KONAN_NO_64BIT_ATOMIC=1
 
 # Android ARM64, based on NDK.
 targetToolchain.macos_x64-android_arm64 = target-toolchain-2-osx-android_ndk

kotlin-native/runtime/src/main/cpp/Atomic.cpp

@@ -92,14 +92,25 @@ KInt Kotlin_AtomicInt_get(KRef thiz) {
     return getImpl<KInt>(thiz);
 }
 
-KLong Kotlin_AtomicLong_addAndGet(KRef thiz, KLong delta) {
-    return addAndGetImpl(thiz, delta);
-}
-
 #if KONAN_NO_64BIT_ATOMIC
 static int lock64 = 0;
 #endif
 
+KLong Kotlin_AtomicLong_addAndGet(KRef thiz, KLong delta) {
+#if KONAN_NO_64BIT_ATOMIC
+    // Potentially huge performance penalty, but correct.
+    while (compareAndSwap(&lock64, 0, 1) != 0);
+    volatile KLong* address = getValueLocation<KLong>(thiz);
+    KLong old = *address;
+    KLong newValue = old + delta;
+    *address = newValue;
+    compareAndSwap(&lock64, 1, 0);
+    return newValue;
+#else
+    return addAndGetImpl(thiz, delta);
+#endif
+}
+
 KLong Kotlin_AtomicLong_compareAndSwap(KRef thiz, KLong expectedValue, KLong newValue) {
 #if KONAN_NO_64BIT_ATOMIC
     // Potentially huge performance penalty, but correct.