Test for preservation of exception order with code motion

tests/compiler/dart2js_extra/code_motion_exception_test.dart

+// Copyright (c) 2011, 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.
+
+import "package:expect/expect.dart";
+
+// Test for correct order of exceptions in code with checks that could be moved
+// merged from successors into a dominator.
+
+get never => new DateTime.now().millisecondsSinceEpoch == 42;
+get always => new DateTime.now().millisecondsSinceEpoch > 42;
+
+// gA and gB have type [null|num], so they compile to a receiver check, and
+// argument check and then the operation.
+var gA;  // [null|num]
+var gB;  // [null|num]
+
+foo1(a, b) {
+  // The checks on a and b are not equivalent, so can't be merged.
+  if (never) {
+    return a ^ b;
+  } else {
+    return b ^ a;
+  }
+}
+
+call1() { return foo1(gA, gB); }
+
+test1() {
+  gA = 1;
+  gB = 2;
+  Expect.equals(3, call1());
+
+  gA = null;
+  gB = null;
+  Expect.throws(call1, (e) => e is NoSuchMethodError, 'foo1($gA, $gB) NSME');
+
+  gA = 1;
+  gB = null;
+  Expect.throws(call1, (e) => e is NoSuchMethodError, 'foo1($gA, $gB) NSME');
+
+  gA = null;
+  gB = 2;
+  Expect.throws(call1, (e) => e is ArgumentError,  'foo1($gA, $gB) AE');
+}
+
+
+foo2a(a, b) {
+  // The common receiver check on [a] cannot be merged because the operation
+  // (selector) is different.
+  // The common argument check on [b] cannot be merged because it must happen
+  // after the receiver check.
+  if (never) {
+    return a ^ b;
+  } else {
+    return a & b;
+  }
+}
+
+foo2b(a, b) {
+  // Same a foo2a except which branch dynamically taken.
+  if (always) {
+    return a ^ b;
+  } else {
+    return a & b;
+  }
+}
+
+call2a() { return foo2a(gA, gB); }
+call2b() { return foo2b(gA, gB); }
+
+checkNSME(text) {
+  return (e) {
+    Expect.isTrue(e is NoSuchMethodError,
+        'expecting NoSuchMethodError, got "${e.runtimeType}"');
+    Expect.isTrue('$e'.contains(text),  '"$e".contains("$text")');
+    return e is NoSuchMethodError;
+  };
+}
+
+test2() {
+  gA = 1;
+  gB = 2;
+  Expect.equals(0, call2a());
+  Expect.equals(3, call2b());
+
+  gA = null;
+  gB = null;
+  Expect.throws(call2a, checkNSME(r'$and'), 'foo2($gA, $gB) NSME');
+  Expect.throws(call2b, checkNSME(r'$xor'), 'foo2($gA, $gB) NSME');
+
+  gA = 1;
+  gB = null;
+  Expect.throws(call2a, (e) => e is ArgumentError, 'foo2($gA, $gB) AE');
+  Expect.throws(call2b, (e) => e is ArgumentError, 'foo2($gA, $gB) AE');
+
+  gA = null;
+  gB = 2;
+  Expect.throws(call2a, checkNSME(r'$and'),  'foo2($gA, $gB) NSME');
+  Expect.throws(call2b, checkNSME(r'$xor'),  'foo2($gA, $gB) NSME');
+}
+
+main() {
+  test1();
+  test2();
+}