Fix library cycle computation in the presence of library handles.

Fix library cycle computation in the presence of library handles.

R=brianwilkerson@google.com

Committed: https://github.com/dart-lang/sdk/commit/da6033a7e2a6099820355caa3aae2c653e67f707

[Paul Berry, 2016-02-25 19:04:48]

paulberry@google.com changed reviewers:
+ brianwilkerson@google.com

[Brian Wilkerson, 2016-02-25 20:47:39]

LGTM

https://codereview.chromium.org/1736013002/diff/1/pkg/analyzer/lib/src/dart/e...
File pkg/analyzer/lib/src/dart/element/element.dart (right):

https://codereview.chromium.org/1736013002/diff/1/pkg/analyzer/lib/src/dart/e...
pkg/analyzer/lib/src/dart/element/element.dart:3273: // as any libraries they
import or export.  Try to find a better way.
Eventually, resynthesis should be lazy, in which case we should only need to
resynthesize the import and export elements. Is that true?

[Paul Berry, 2016-02-25 21:08:30]

https://codereview.chromium.org/1736013002/diff/1/pkg/analyzer/lib/src/dart/e...
File pkg/analyzer/lib/src/dart/element/element.dart (right):

https://codereview.chromium.org/1736013002/diff/1/pkg/analyzer/lib/src/dart/e...
pkg/analyzer/lib/src/dart/element/element.dart:3273: // as any libraries they
import or export.  Try to find a better way.
On 2016/02/25 20:47:39, Brian Wilkerson wrote:
> Eventually, resynthesis should be lazy, in which case we should only need to
> resynthesize the import and export elements. Is that true?

Yes, I hope to do that, but even under the optimistic assumption that we can do
that easily, computing a library cycle will still be more expensive than I'd
like, because it will require visiting the import and export elements of all
libraries in the cycle *and* all libraries imported or exported by those
libraries.  That's a lot of libraries to visit, and many of them are probably
libraries we won't need to resynthesize for any other reason.

An alternative, which I think would be easier and result in an even bigger
savings, would be to compute all the library cycles at summary generation time
and store them in the summary.  Then the only thing we would need to
resynthesize in order to figure out the library cycle for library X would be
library X itself.

[Paul Berry, 2016-02-25 21:12:02]

Description was changed from

==========
Fix library cycle computation in the presence of library handles.
==========

to

==========
Fix library cycle computation in the presence of library handles.

R=brianwilkerson@google.com

Committed:
https://github.com/dart-lang/sdk/commit/da6033a7e2a6099820355caa3aae2c653e67f707
==========

[Paul Berry, 2016-02-25 21:12:03]

Committed patchset #1 (id:1) manually as
da6033a7e2a6099820355caa3aae2c653e67f707 (presubmit successful).