[async-iteration] implement Async-from-Sync Iterator

test/cctest/interpreter/test-bytecode-generator.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <fstream>
 
 #include "src/v8.h"
 
 #include "src/interpreter/bytecode-array-iterator.h"
 #include "src/interpreter/bytecode-generator.h"
@@ skipping 2353 matching lines @@
       "class A { constructor(...args) { this.args = args; } }\n"
       "new A(0, ...[1, 2, 3]);\n",
 
       "class A { constructor(...args) { this.args = args; } }\n"
       "new A(0, ...[1, 2, 3], 4);\n"};
 
   CHECK(CompareTexts(BuildActual(printer, snippets),
                      LoadGolden("NewAndSpread.golden")));
 }
 
+TEST(ForAwaitOf) {
+  bool old_flag = i::FLAG_harmony_async_iteration;
+  i::FLAG_harmony_async_iteration = true;
+  InitializedIgnitionHandleScope scope;
+  BytecodeExpectationsPrinter printer(CcTest::isolate());
+  printer.set_wrap(false);
+  printer.set_test_function_name("f");
+
+  const char* snippets[] = {
+      "async function f() {\n"
+      "  for await (let x of [1, 2, 3]) {}\n"
+      "}\n"
+      "f();\n",
+
+      "async function f() {\n"
+      "  for await (let x of [1, 2, 3]) { return x; }\n"
+      "}\n"
+      "f();\n",
+
+      "async function f() {\n"
+      "  for await (let x of [10, 20, 30]) {\n"
+      "    if (x == 10) continue;\n"
+      "    if (x == 20) break;\n"
+      "  }\n"
+      "}\n"
+      "f();\n",
+
+      "async function f() {\n"
+      "  var x = { 'a': 1, 'b': 2 };\n"
+      "  for (x['a'] of [1,2,3]) { return x['a']; }\n"
+      "}\n"
+      "f();\n"};
+
+  CHECK(CompareTexts(BuildActual(printer, snippets),
+                     LoadGolden("ForAwaitOf.golden")));
+
+  i::FLAG_harmony_async_iteration = old_flag;
+}
+
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8