Inline native String.charCodeAt in optimized code.

tests/language/optimized_constant_array_string_access.dart

+// 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.
+
+// Test optimized constant string and constant array access.
+
+int testConstantStringAndIndexCharCodeAt() {
+  int test(b) {
+    if (b) return "hest".charCodeAt(400);
+    return "hest".charCodeAt(2);
+  }
+
+  Expect.throws(() => test(true));
+  for (int i = 0; i < 10000; i++) test(false);
+  Expect.throws(() => test(true));
+}
+
+
+int testConstantArrayAndIndexAt() {
+  int test(b) {
+    var a = const [1,2,3,4];
+    if (b) return a[400];
+    return a[2];
+  }
+
+  Expect.throws(() => test(true));
+  for (int i = 0; i < 10000; i++) test(false);
+  Expect.throws(() => test(true));
+}
+
+
+foo(a) {
+  if (a == 1) { return 2; }
+  var aa = const [1, 2];
+  return aa[2.3];
+}
+
+
+int testNonSmiIndex() {
+  for (int i = 0; i < 10000; i++) { foo(1); }
+  Expect.throws(() => foo(2));
+}
+
+
+main() {
+  testConstantStringAndIndexCharCodeAt();
+  testConstantArrayAndIndexAt();
+  testNonSmiIndex();
+}