Do not use guarded cid on externalizable cid-s (one and two byte strings).

runtime/vm/dart_api_impl_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "bin/builtin.h"
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 #include "platform/assert.h"
 #include "platform/json.h"
@@ skipping 7098 matching lines @@
   Dart_ExitScope();
 }
 
 
 static Dart_NativeFunction ExternalStringDeoptimize_native_lookup(
     Dart_Handle name, int argument_count) {
   return reinterpret_cast<Dart_NativeFunction>(&A_change_str_native);
 }
 
 
+// Do not use guarding mechanism on externalizable classes, since their class
+// can change on the fly,
+TEST_CASE(GuardExternalizedString) {
+  const char* kScriptChars =
+      "main() {\n"
+      "  var a = new A('hello');\n"
+      "  var res = runOne(a);\n"
+      "  if (res != 10640000) return -1;\n"
+      "  change_str(a.f);\n"
+      "  res = runOne(a);\n"
+      "  return res;\n"
+      "}\n"
+      "runOne(a) {\n"
+      "  var sum = 0;\n"
+      "  for (int i = 0; i < 20000; i++) {\n"
+      "    for (int j = 0; j < a.f.length; j++) {\n"
+      "      sum += a.f.codeUnitAt(j);\n"
+      "    }\n"
+      "  }\n"
+      "  return sum;\n"
+      "}\n"
+      "class A {\n"
+      "  var f;\n"
+      "  A(this.f);\n"
+      "}\n"
+      "change_str(String s) native 'A_change_str';\n"
+      "";
+  Dart_Handle lib =
+      TestCase::LoadTestScript(kScriptChars,
+                               &ExternalStringDeoptimize_native_lookup);
+  Dart_Handle result = Dart_Invoke(lib,
+                                   NewString("main"),
+                                   0,
+                                   NULL);
+  int64_t value = 0;
+  result = Dart_IntegerToInt64(result, &value);
+  EXPECT_VALID(result);
+  EXPECT_EQ(10640000, value);
+}
+
+
 TEST_CASE(ExternalStringDeoptimize) {
   const char* kScriptChars =
       "String str = 'A';\n"
       "class A {\n"
       "  static change_str(String s) native 'A_change_str';\n"
       "}\n"
       "sum_chars(String s, bool b) {\n"
       "  var result = 0;\n"
       "  for (var i = 0; i < s.length; i++) {\n"
       "    if (b && i == 0) A.change_str(str);\n"
@@ skipping 73 matching lines @@
                                    NewString("main"),
                                    0,
                                    NULL);
   int64_t value = 0;
   result = Dart_IntegerToInt64(result, &value);
   EXPECT_VALID(result);
   EXPECT_EQ(8, value);
 }
 
 }  // namespace dart