Support argument definition test in constructors.

Support argument definition test in constructors.
Committed: https://code.google.com/p/dart/source/detail?r=14251

[ngeoffray, 2012-10-28 18:14:31]

Fixes issue 6225.

[floitsch, 2012-10-29 10:32:30]

LGTM.
This is better than before, but as discussed, it's not yet completely right.
For example we cannot use optional arguments in the super initializers:
class A {
  var foo;
  A([x]) : foo = x { print(?x); }
}

class B extends A {
  B() : super();
}
main() {
  print(new C().foo);
}

[ngeoffray, 2012-10-29 17:35:10]

PTAL, I am now passing the parameter checks as extra parameters, like Florian
and I discussed. This is necessary to correctly implement:

A([a]) : field = ?a, otherField = a++ {
  print(?a);
  print(a);
}

[floitsch, 2012-10-29 21:45:45]

LGTM.

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
File lib/compiler/implementation/ssa/builder.dart (right):

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/builder.dart:1377: // If parameters are checked,
we pass what we already computed
If parameters are checked, we pass the already computed boolean to the
constructor body.

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/builder.dart:1412: HInstruction check;
Keep the declaration at the use-point. No need to move it outside the if's. It
actually makes the method one line longer...

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/builder.dart:1417: // parameter was passed in
extra parameters.
A generative constructor body receives extra parameters that indicate if a
parameter was passed to the factory.

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/builder.dart:1420: } else {
You could avoid the else (and the indentation) by just returning in the special
case. But I'm fine the way it is.

[ngeoffray, 2012-10-30 09:34:46]

Thanks Florian

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
File lib/compiler/implementation/ssa/builder.dart (right):

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/builder.dart:1377: // If parameters are checked,
we pass what we already computed
On 2012/10/29 21:45:45, floitsch wrote:
> If parameters are checked, we pass the already computed boolean to the
> constructor body.

Done.

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/builder.dart:1412: HInstruction check;
On 2012/10/29 21:45:45, floitsch wrote:
> Keep the declaration at the use-point. No need to move it outside the if's. It
> actually makes the method one line longer...

The variable is used outside the if/else (line 1462), so I'm keeping the
declaration here.

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/builder.dart:1417: // parameter was passed in
extra parameters.
On 2012/10/29 21:45:45, floitsch wrote:
> A generative constructor body receives extra parameters that indicate if a
> parameter was passed to the factory.

Done.

https://codereview.chromium.org/11346002/diff/8001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/builder.dart:1420: } else {
On 2012/10/29 21:45:45, floitsch wrote:
> You could avoid the else (and the indentation) by just returning in the
special
> case. But I'm fine the way it is.

No, there's a shared updateLocal call line 1462.