d8 Worker test of SharedArrayBuffer transferring

test/mjsunit/d8-worker-sharedarraybuffer.js

Index: test/mjsunit/d8-worker-sharedarraybuffer.js
diff --git a/test/mjsunit/d8-worker-spawn-worker.js b/test/mjsunit/d8-worker-sharedarraybuffer.js
similarity index 63%
copy from test/mjsunit/d8-worker-spawn-worker.js
copy to test/mjsunit/d8-worker-sharedarraybuffer.js
index b9d7f9ade4fd116837c275a73867eeda26076e5a..e10e738bf2bb05cec920721d640baabe2675c7ca 100644
--- a/test/mjsunit/d8-worker-spawn-worker.js
+++ b/test/mjsunit/d8-worker-sharedarraybuffer.js
@@ -25,22 +25,47 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+// Flags: --harmony-sharedarraybuffer --harmony-atomics
+
+function f() {
+  onmessage = function(m) {
+    var sab = m;
+    var ta = new Uint32Array(sab);
+    if (sab.byteLength !== 16) {
+      throw new Error("SharedArrayBuffer transfer byteLength");
+    }
+
+    for (var i = 0; i < 4; ++i) {
+      if (ta[i] !== i) {
+        throw new Error("SharedArrayBuffer transfer value " + i);
+      }
+    }
+
+    // Atomically update ta[0]
+    Atomics.store(ta, 0, 100);
+  };
+}
+
 if (this.Worker) {
-  function f() {
-    var g = function () {
-      postMessage(42);
-    };
-
-    var w = new Worker(g);
-
-    onmessage = function(parentMsg) {
-      w.postMessage(parentMsg);
-      var childMsg = w.getMessage();
-      postMessage(childMsg);
-    };
+  var w = new Worker(f);
+
+  var sab = new SharedArrayBuffer(16);
+  var ta = new Uint32Array(sab);
+  for (var i = 0; i < 4; ++i) {
+    ta[i] = i;
   }
 
-  var w = new Worker(f);
-  w.postMessage(9);
-  assertEquals(42, w.getMessage());
+  // Transfer SharedArrayBuffer
+  w.postMessage(sab, [sab]);
+  assertEquals(16, sab.byteLength);  // ArrayBuffer should not be neutered.
+
+  // Spinwait for the worker to update ta[0]
+  var ta0;
+  while ((ta0 = Atomics.load(ta, 0)) == 0) {}
+
+  assertEquals(100, ta0);
+
+  w.terminate();
+
+  assertEquals(16, sab.byteLength);  // Still not neutered.
 }