Fix crash in SSA builder for receiver-less calls. Not sure this is correct.

Don't intercept receiver-less calls.

Committed: https://code.google.com/p/dart/source/detail?r=4438

[floitsch, 2012-02-20 12:11:03]

FYI.

https://chromiumcodereview.appspot.com/9423040/diff/1/dart/frog/leg/ssa/build...
File dart/frog/leg/ssa/builder.dart (right):

https://chromiumcodereview.appspot.com/9423040/diff/1/dart/frog/leg/ssa/build...
dart/frog/leg/ssa/builder.dart:1499: if (methodInterceptionEnabled) {
&& receiver !== null

This should be more correct and more efficient.
If we have a 'this' (and that's when we don't have a receiver) then we know that
the Dart object exists and that we don't need to intercept.

[ahe, 2012-02-20 12:33:22]

https://chromiumcodereview.appspot.com/9423040/diff/1/dart/frog/leg/ssa/build...
File dart/frog/leg/ssa/builder.dart (right):

https://chromiumcodereview.appspot.com/9423040/diff/1/dart/frog/leg/ssa/build...
dart/frog/leg/ssa/builder.dart:1499: if (methodInterceptionEnabled) {
On 2012/02/20 12:11:03, floitsch wrote:
> && receiver !== null
> 
> This should be more correct and more efficient.
> If we have a 'this' (and that's when we don't have a receiver) then we know
that
> the Dart object exists and that we don't need to intercept.

Thank you, Florian. That makes sense. I assume you mean:

&& node.receiver !== null.

[floitsch, 2012-02-20 12:56:51]

and with that change LGTM.

https://chromiumcodereview.appspot.com/9423040/diff/1/dart/frog/leg/ssa/build...
File dart/frog/leg/ssa/builder.dart (right):

https://chromiumcodereview.appspot.com/9423040/diff/1/dart/frog/leg/ssa/build...
dart/frog/leg/ssa/builder.dart:1499: if (methodInterceptionEnabled) {
On 2012/02/20 12:33:22, ahe wrote:
> On 2012/02/20 12:11:03, floitsch wrote:
> > && receiver !== null
> > 
> > This should be more correct and more efficient.
> > If we have a 'this' (and that's when we don't have a receiver) then we know
> that
> > the Dart object exists and that we don't need to intercept.
> 
> Thank you, Florian. That makes sense. I assume you mean:
> 
> && node.receiver !== null.

correct.

[ngeoffray, 2012-02-20 17:14:08]

LGTM!

https://chromiumcodereview.appspot.com/9423040/diff/5001/dart/frog/leg/lib/js...
File dart/frog/leg/lib/js_helper.dart (right):

https://chromiumcodereview.appspot.com/9423040/diff/5001/dart/frog/leg/lib/js...
dart/frog/leg/lib/js_helper.dart:572: var length = JS("num", @"$0.length",
receiver);
You could consider just using Dart code here, and let our optimizers handle the
rest.

https://chromiumcodereview.appspot.com/9423040/diff/5001/dart/frog/leg/ssa/bu...
File dart/frog/leg/ssa/builder.dart (right):

https://chromiumcodereview.appspot.com/9423040/diff/5001/dart/frog/leg/ssa/bu...
dart/frog/leg/ssa/builder.dart:1499: if (methodInterceptionEnabled &&
node.receiver !== null) {
Maybe it would be clearer to check if you actually have an element for that
call. If you have an element, you know it should not be intercepted.

Also, whatever solution, this fix deserves a comment.

[ahe, 2012-02-22 09:12:57]

Hi Florian and Nicolas,

Thank you for taking a look. I'll follow up on your comments in another CL.

Cheers,
Peter