An optimization pass that annotates array acceses so that the validating rewriter can skip checks

Implements an optimization pass between ConsolidateCode and
ValidateJavascript that folds converts foo[bar] to foo[+bar] when bar
is provably a publicly accessible array member regardless of what foo
is.

This was derived from http://codereview.appspot.com/8703/ and depends
on Jasvir's recent work to make negative array indices on function and
arguments instances inaccessible.


Submitted @ r4313

[Jasvir, 2010-10-07 21:05:11]

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/parser/quasi...
File src/com/google/caja/parser/quasiliteral/opt/ArrayIndexOptimization.java
(right):

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/parser/quasi...
src/com/google/caja/parser/quasiliteral/opt/ArrayIndexOptimization.java:40: *
<p>The CajitaRewriter will optimize reads of properties where the index
Update to reference ES53 (which also does this)

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/plugin/Pipel...
File src/com/google/caja/plugin/PipelineMaker.java (right):

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/plugin/Pipel...
src/com/google/caja/plugin/PipelineMaker.java:236: out.add(new
OptimizeJavascriptStage());
Can we get no-optimize as an option?

http://codereview.appspot.com/2241042/diff/1/tests/com/google/caja/parser/qua...
File
tests/com/google/caja/parser/quasiliteral/opt/ArrayIndexOptimizationTest.java
(right):

http://codereview.appspot.com/2241042/diff/1/tests/com/google/caja/parser/qua...
tests/com/google/caja/parser/quasiliteral/opt/ArrayIndexOptimizationTest.java:138:
+ "function map(f, arr) {\n"
I don't get it - how could this possibly be the optimization of the reference
example?

[Jasvir, 2010-10-07 21:05:51]

http://codereview.appspot.com/2241042/diff/1/tests/com/google/caja/parser/qua...
File
tests/com/google/caja/parser/quasiliteral/opt/ArrayIndexOptimizationTest.java
(right):

http://codereview.appspot.com/2241042/diff/1/tests/com/google/caja/parser/qua...
tests/com/google/caja/parser/quasiliteral/opt/ArrayIndexOptimizationTest.java:138:
+ "function map(f, arr) {\n"
Ah ah ah - this is a copy and paste error.  Please snapshot after running the
tests.

On 2010/10/07 21:05:11, jasvir wrote:
> I don't get it - how could this possibly be the optimization of the reference
> example?

[MikeSamuel, 2010-10-26 00:01:59]

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/parser/quasi...
File src/com/google/caja/parser/quasiliteral/opt/ArrayIndexOptimization.java
(right):

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/parser/quasi...
src/com/google/caja/parser/quasiliteral/opt/ArrayIndexOptimization.java:40: *
<p>The CajitaRewriter will optimize reads of properties where the index
On 2010/10/07 21:05:11, jasvir wrote:
> Update to reference ES53 (which also does this)

Done.

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/plugin/Pipel...
File src/com/google/caja/plugin/PipelineMaker.java (right):

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/plugin/Pipel...
src/com/google/caja/plugin/PipelineMaker.java:236: out.add(new
OptimizeJavascriptStage());
On 2010/10/07 21:05:11, jasvir wrote:
> Can we get no-optimize as an option?

How would that work?
And who would be a client of this?
It doesn't seem like there is any identifiable property of the input JS that we
would hinge this on.

[Jasvir, 2010-10-26 18:15:33]

LGTM

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/plugin/Pipel...
File src/com/google/caja/plugin/PipelineMaker.java (right):

http://codereview.appspot.com/2241042/diff/1/src/com/google/caja/plugin/Pipel...
src/com/google/caja/plugin/PipelineMaker.java:236: out.add(new
OptimizeJavascriptStage());
.given(JS).produces(CAJOLED_MODULE_UNOPTIMIZED)?

Else any client that requests CAJOLED_MODULE given JS always gets optimized
javascript.  Given that the only optimization currently available is array
optimization which produces code that is as understandable as the original, its
not critical.