Implement a native identical function in the VM.

Implement a native identical function in the VM.

Returns true if objects are the same instance.
Adds an identical closure test (disabled for dart2js pending https://chromiumcodereview.appspot.com/11612022/). 

BUG=7378
Committed: https://code.google.com/p/dart/source/detail?r=16461

[srdjan, 2012-12-17 19:42:47]

https://codereview.chromium.org/11613003/diff/2001/runtime/lib/identical.cc
File runtime/lib/identical.cc (right):

https://codereview.chromium.org/11613003/diff/2001/runtime/lib/identical.cc#n...
runtime/lib/identical.cc:16: return Bool::Get(a.Equals(b));
YOu need to do the same for Doubles, Mints and Bigints

https://codereview.chromium.org/11613003/diff/2001/tests/language/identical_c...
File tests/language/identical_closure_test.dart (right):

https://codereview.chromium.org/11613003/diff/2001/tests/language/identical_c...
tests/language/identical_closure_test.dart:23: Expect.isTrue(myIdentical(a, b));
Add tests for doubles, mints and bigints.

[Max Heinritz (Google), 2012-12-17 21:15:23]

https://codereview.chromium.org/11613003/diff/2001/runtime/lib/identical.cc
File runtime/lib/identical.cc (right):

https://codereview.chromium.org/11613003/diff/2001/runtime/lib/identical.cc#n...
runtime/lib/identical.cc:16: return Bool::Get(a.Equals(b));
On 2012/12/17 19:42:47, srdjan wrote:
> YOu need to do the same for Doubles, Mints and Bigints

Done.

https://codereview.chromium.org/11613003/diff/2001/tests/language/identical_c...
File tests/language/identical_closure_test.dart (right):

https://codereview.chromium.org/11613003/diff/2001/tests/language/identical_c...
tests/language/identical_closure_test.dart:23: Expect.isTrue(myIdentical(a, b));
On 2012/12/17 19:42:47, srdjan wrote:
> Add tests for doubles, mints and bigints.

Done.

[srdjan, 2012-12-17 22:10:19]

https://codereview.chromium.org/11613003/diff/11001/runtime/lib/identical.cc
File runtime/lib/identical.cc (right):

https://codereview.chromium.org/11613003/diff/11001/runtime/lib/identical.cc#...
runtime/lib/identical.cc:11: Instance, a, arguments->NativeArgAt(0));
Null can be an argument: identical(null, 2). Please add test.

https://codereview.chromium.org/11613003/diff/11001/runtime/lib/identical.cc#...
runtime/lib/identical.cc:14: // If objects are both numbers of the same type,
compare values.
Suggestion:

if (a.raw() == b.raw()) return Bool::True();
if (a.IsInteger() && b.IsInteger()) {
  return Bool::Get(a.Equals(b));
}
if (a.IsDouble() && b.IsDouble()) {
  if (a.Equals(b)) return Bool::True();
  // Check for NaN
  Double a_double = Double::Cast(a);
  Double b_double = Double::Cast(b);
  if (is_nan(a_double.value()) && is_nan(a_double.value())) {
    return Bool::True();
  }
}
return Bool::False;

https://codereview.chromium.org/11613003/diff/11001/tests/language/identical_...
File tests/language/identical_closure_test.dart (right):

https://codereview.chromium.org/11613003/diff/11001/tests/language/identical_...
tests/language/identical_closure_test.dart:45: Expect.isFalse(myIdentical(42,
null));
Add check:

Expect.isTrue(myIdentical(double.NAN, double.NAN()));

[Max Heinritz (Google), 2012-12-17 23:27:57]

https://codereview.chromium.org/11613003/diff/11001/runtime/lib/identical.cc
File runtime/lib/identical.cc (right):

https://codereview.chromium.org/11613003/diff/11001/runtime/lib/identical.cc#...
runtime/lib/identical.cc:11: Instance, a, arguments->NativeArgAt(0));
On 2012/12/17 22:10:19, srdjan wrote:
> Null can be an argument: identical(null, 2). Please add test.

Done.

https://codereview.chromium.org/11613003/diff/11001/runtime/lib/identical.cc#...
runtime/lib/identical.cc:14: // If objects are both numbers of the same type,
compare values.
On 2012/12/17 22:10:19, srdjan wrote:
> Suggestion:
> 
> if (a.raw() == b.raw()) return Bool::True();
> if (a.IsInteger() && b.IsInteger()) {
>   return Bool::Get(a.Equals(b));
> }
> if (a.IsDouble() && b.IsDouble()) {
>   if (a.Equals(b)) return Bool::True();
>   // Check for NaN
>   Double a_double = Double::Cast(a);
>   Double b_double = Double::Cast(b);
>   if (is_nan(a_double.value()) && is_nan(a_double.value())) {
>     return Bool::True();
>   }
> }
> return Bool::False;

Done.

https://codereview.chromium.org/11613003/diff/11001/tests/language/identical_...
File tests/language/identical_closure_test.dart (right):

https://codereview.chromium.org/11613003/diff/11001/tests/language/identical_...
tests/language/identical_closure_test.dart:45: Expect.isFalse(myIdentical(42,
null));
On 2012/12/17 22:10:19, srdjan wrote:
> Add check:
> 
> Expect.isTrue(myIdentical(double.NAN, double.NAN()));

Done.

[srdjan, 2012-12-17 23:30:20]

LGTM with last comments.

https://codereview.chromium.org/11613003/diff/11002/runtime/lib/identical.cc
File runtime/lib/identical.cc (right):

https://codereview.chromium.org/11613003/diff/11002/runtime/lib/identical.cc#...
runtime/lib/identical.cc:13: Instance, a, arguments->NativeArgAt(0));
Can this fit in one line (80 chars).

https://codereview.chromium.org/11613003/diff/11002/runtime/lib/identical.cc#...
runtime/lib/identical.cc:15: Instance, b, arguments->NativeArgAt(1));
Ditto.

https://codereview.chromium.org/11613003/diff/11002/runtime/lib/identical.cc#...
runtime/lib/identical.cc:22: // Check for NaN
Terminate comment with a period.

[siva, 2012-12-18 01:16:04]

lgtm