Dart VM: Simplify code generation for equality operators.

tests/standalone/debugger/step_in_equals_test.dart

Index: tests/standalone/debugger/step_in_equals_test.dart
===================================================================
--- tests/standalone/debugger/step_in_equals_test.dart	(revision 0)
+++ tests/standalone/debugger/step_in_equals_test.dart	(revision 0)
@@ -0,0 +1,42 @@
+// Copyright (c) 2013, 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 "debug_lib.dart";
+
+class MyClass {
+  operator ==(other) {
+    print(other);
+    return true;  // Breakpoint #3.
+  }
+}
+
+main() {
+  if (RunScript(testScript)) return;
+  var a = new MyClass();
+  var b = null;
+  var x = a == b;  // Breakpoint #1.

[hausner, 2013/09/25 16:36:11]

I think the case of comparing to null explicitly is handled through a different
code path in the compiler. Please add a test similar to:

if (x == null) {  // make sure you can break on this line.
  ...
}

[Florian Schneider, 2013/09/26 11:34:21]

Done. Appended (x == null) and (null == x) to the test.

+  print(x);
+  b = 123;
+  a == b;  // Breakpoint #2.
+  print("ok");
+}
+
+var testScript = [
+  MatchFrames(["main"]),
+  SetBreakpoint(18),
+  SetBreakpoint(21),
+  SetBreakpoint(10),
+  Resume(),
+  MatchFrames(["main"]),  // At breakpoint #1.
+  StepInto(),
+  MatchFrames(["main"]),  // Don't step into == method because of null.
+  Resume(),
+  MatchFrames(["main"]), // At breakpoint #2.
+  StepInto(),
+  StepInto(),
+  MatchFrames(["MyClass.==", "main"]),  // At MyClass.== entry.
+  Resume(),
+  MatchFrames(["MyClass.==", "main"]),  // At breakpoint #3.
+  Resume()
+];