Add bailouts to dart backend.

Add bailouts to dart backend.

R=ahe@google.com,smok@google.com

Committed: https://code.google.com/p/dart/source/detail?r=9175

[ahe, 2012-06-27 10:52:33]

LGTM, but you shouldn't keep this approach long.

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/backend.dart (right):

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:40: // TODO(antonm):
eventually bailouts will be  proper errors.
Not a proper sentence (eventually -> Eventually).

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:41: bailout(String reason)
{
Type on argument, so please provide a return type.

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:42: throw new
BailoutException(reason);
Our experience from the type checker is that throwing exceptions is extremely
slow. I wouldn't use this approach if I were you.

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:52: bailout_reason =
"${e.reason}";
You should escape " and \

[Anton Muhin, 2012-06-27 15:59:46]

Thanks a lot for review, submitting.

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/backend.dart (right):

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:40: // TODO(antonm):
eventually bailouts will be  proper errors.
On 2012/06/27 10:52:33, ahe wrote:
> Not a proper sentence (eventually -> Eventually).

Done.

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:41: bailout(String reason)
{
On 2012/06/27 10:52:33, ahe wrote:
> Type on argument, so please provide a return type.

Done.

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:42: throw new
BailoutException(reason);
Thanks a lot for a tip.  I'll leave it for now as I hope it won't stay long, but
if it'll, I'll change it to something speedier.

On 2012/06/27 10:52:33, ahe wrote:
> Our experience from the type checker is that throwing exceptions is extremely
> slow. I wouldn't use this approach if I were you.

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:52: bailout_reason =
"${e.reason}";
On 2012/06/27 10:52:33, ahe wrote:
> You should escape " and \

Sorry, why?

[ahe, 2012-06-27 20:34:08]

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/backend.dart (right):

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:52: bailout_reason =
"${e.reason}";
What if e.reason is: 'cannot find "foo"'

On 2012/06/27 15:59:46, antonmuhin wrote:
> On 2012/06/27 10:52:33, ahe wrote:
> > You should escape " and \
> 
> Sorry, why?

[Anton Muhin, 2012-06-28 14:19:05]

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/backend.dart (right):

https://chromiumcodereview.appspot.com/10662055/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:52: bailout_reason =
"${e.reason}";
Yes, that may happen, but I hope bailouts will go out soon, so let's solve it if
it shows up.

On 2012/06/27 20:34:08, ahe wrote:
> What if e.reason is: 'cannot find "foo"'
> 
> On 2012/06/27 15:59:46, antonmuhin wrote:
> > On 2012/06/27 10:52:33, ahe wrote:
> > > You should escape " and \
> > 
> > Sorry, why?
>