Use ElementAnnotation as the ConstantEvaluationTarget for annotations.

Use ElementAnnotation as the ConstantEvaluationTarget for annotations.

Previously, we had a special class,
ConstantEvaluationTarget_Annotation, for this purpose.  It held on to
a the AST node for the annotation.  This was bad because it meant that
the presence of any ConstantEvaluationTarget_Annotation referring to a
given compilation unit would keep the entire compilation unit's AST in
memory.

Now we copy just the portions of the AST we need into
ElementAnnotation, just as we do for all other constant evaluation
targets.  In addition to saving memory, this paves the way for
supporting annotations in summaries, by making it possible to compute
the constant value of an annotation without having to consult the full
AST.

Fixes #25285.

R=brianwilkerson@google.com

Committed: https://github.com/dart-lang/sdk/commit/c43622e89727dd08978ab8ce208d2b863f0b07f1

[Paul Berry, 2016-02-04 22:27:15]

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

[Brian Wilkerson, 2016-02-04 22:37:59]

LGTM

[Paul Berry, 2016-02-04 23:22:45]

Description was changed from

==========
Use ElementAnnotation as the ConstantEvaluationTarget for annotations.

Previously, we had a special class,
ConstantEvaluationTarget_Annotation, for this purpose.  It held on to
a the AST node for the annotation.  This was bad because it meant that
the presence of any ConstantEvaluationTarget_Annotation referring to a
given compilation unit would keep the entire compilation unit's AST in
memory.

Now we copy just the portions of the AST we need into
ElementAnnotation, just as we do for all other constant evaluation
targets.  In addition to saving memory, this paves the way for
supporting annotations in summaries, by making it possible to compute
the constant value of an annotation without having to consult the full
AST.

Fixes #25285.
==========

to

==========
Use ElementAnnotation as the ConstantEvaluationTarget for annotations.

Previously, we had a special class,
ConstantEvaluationTarget_Annotation, for this purpose.  It held on to
a the AST node for the annotation.  This was bad because it meant that
the presence of any ConstantEvaluationTarget_Annotation referring to a
given compilation unit would keep the entire compilation unit's AST in
memory.

Now we copy just the portions of the AST we need into
ElementAnnotation, just as we do for all other constant evaluation
targets.  In addition to saving memory, this paves the way for
supporting annotations in summaries, by making it possible to compute
the constant value of an annotation without having to consult the full
AST.

Fixes #25285.

R=brianwilkerson@google.com

Committed:
https://github.com/dart-lang/sdk/commit/c43622e89727dd08978ab8ce208d2b863f0b07f1
==========

[Paul Berry, 2016-02-04 23:22:46]

Committed patchset #1 (id:1) manually as
c43622e89727dd08978ab8ce208d2b863f0b07f1 (presubmit successful).