Use dart.tearoff helper at tearoff sites

Use dart.tearoff helper at tearoff sites.

When we tear off a method, replace the obj.foo.bind(obj) pattern with dart.tearoff(obj, 'foo'), and the dart.bind(exp, 'foo') pattern with dart.tearoff(exp, 'foo').  This helper does both the bind and attaches rtti.

This CL also stops binding of static methods when they are town off, since I think this is unnecessary.

BUG=
R=vsm@google.com

Committed: https://github.com/dart-lang/dev_compiler/commit/3f47a80af77a37420e5e5907685a2497cb23c996

[Leaf, 2015-05-19 23:58:57]

leafp@google.com changed reviewers:
+ jmesserly@google.com, vsm@google.com

[vsm, 2015-05-20 15:01:49]

lgtm

[Jennifer Messerly, 2015-05-20 16:05:17]

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
File lib/src/codegen/js_codegen.dart (left):

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
lib/src/codegen/js_codegen.dart:1998: return js.call('#.#.bind(#)',
[_visit(target), name, _visit(target)]);
this makes me a little sad, as we never generate "normal" JavaScript code
anymore. I guess we can bring it back with the --no-rtti compiler option, at
some point in the future?

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
File lib/src/codegen/js_codegen.dart (right):

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
lib/src/codegen/js_codegen.dart:1118: var code = (tearOff) ? 'dart.tearoff(this,
#)' : 'this.#';
I don't think we should call this "tearoff" in generated code. Inside the Dart
team we've used this name in discussions, but it's not a broader term. I chose
"bind" because that's the name JavaScript uses for this concept, and a search
for "javascript bind" or "function bind" finds the right concept.

[Leaf, 2015-05-20 16:35:17]

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
File lib/src/codegen/js_codegen.dart (left):

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
lib/src/codegen/js_codegen.dart:1998: return js.call('#.#.bind(#)',
[_visit(target), name, _visit(target)]);
On 2015/05/20 16:05:17, John Messerly wrote:
> this makes me a little sad, as we never generate "normal" JavaScript code
> anymore. I guess we can bring it back with the --no-rtti compiler option, at
> some point in the future?

Hmm.  I actually kind of felt like it was often an improvement in the generated
code - maybe it's a tradeoff between being idiomatic and being brief?  Can bind
be overridden?  If so then maybe I could work it out so that the original
pattern worked.

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
File lib/src/codegen/js_codegen.dart (right):

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
lib/src/codegen/js_codegen.dart:1118: var code = (tearOff) ? 'dart.tearoff(this,
#)' : 'this.#';
On 2015/05/20 16:05:17, John Messerly wrote:
> I don't think we should call this "tearoff" in generated code. Inside the Dart
> team we've used this name in discussions, but it's not a broader term. I chose
> "bind" because that's the name JavaScript uses for this concept, and a search
> for "javascript bind" or "function bind" finds the right concept.

So you're saying change dart.bind to both bind the function and add rtti and
then just use that?  That's fine by me.

[Jennifer Messerly, 2015-05-20 16:50:30]

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
File lib/src/codegen/js_codegen.dart (left):

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
lib/src/codegen/js_codegen.dart:1998: return js.call('#.#.bind(#)',
[_visit(target), name, _visit(target)]);
On 2015/05/20 16:35:17, leafp wrote:
> On 2015/05/20 16:05:17, John Messerly wrote:
> > this makes me a little sad, as we never generate "normal" JavaScript code
> > anymore. I guess we can bring it back with the --no-rtti compiler option, at
> > some point in the future?
> 
> Hmm.  I actually kind of felt like it was often an improvement in the
generated
> code - maybe it's a tradeoff between being idiomatic and being brief?

yeah, exactly ... in JS it's not something you'd typically call a helper for,
because it's so easy to `.bind(this)`. Then again, if we could turn our
dart_runtime.js more into a general "ES6 with types" library, I think that would
make me feel better about having those runtime helpers and using them so much.

But yeah, no worries, this particular one isn't a big deal in the grand scheme.
My concerns are a bit higher level. Maybe we'll get time at some point for a
coherent readability/design review of the JS we're generating.

>  Can bind
> be overridden?  If so then maybe I could work it out so that the original
> pattern worked.

Kind of. We could alter "Function.prototype.bind". But probably not worth just
for this.

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
File lib/src/codegen/js_codegen.dart (right):

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
lib/src/codegen/js_codegen.dart:1118: var code = (tearOff) ? 'dart.tearoff(this,
#)' : 'this.#';
On 2015/05/20 16:35:17, leafp wrote:
> On 2015/05/20 16:05:17, John Messerly wrote:
> > I don't think we should call this "tearoff" in generated code. Inside the
Dart
> > team we've used this name in discussions, but it's not a broader term. I
chose
> > "bind" because that's the name JavaScript uses for this concept, and a
search
> > for "javascript bind" or "function bind" finds the right concept.
> 
> So you're saying change dart.bind to both bind the function and add rtti and
> then just use that?  That's fine by me.  

err, I think so :). What do we still use "dart.bind" for after your CL?

[Leaf, 2015-05-20 17:05:56]

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
File lib/src/codegen/js_codegen.dart (right):

https://codereview.chromium.org/1142293002/diff/20001/lib/src/codegen/js_code...
lib/src/codegen/js_codegen.dart:1118: var code = (tearOff) ? 'dart.tearoff(this,
#)' : 'this.#';
On 2015/05/20 16:50:30, John Messerly wrote:
> On 2015/05/20 16:35:17, leafp wrote:
> > On 2015/05/20 16:05:17, John Messerly wrote:
> > > I don't think we should call this "tearoff" in generated code. Inside the
> Dart
> > > team we've used this name in discussions, but it's not a broader term. I
> chose
> > > "bind" because that's the name JavaScript uses for this concept, and a
> search
> > > for "javascript bind" or "function bind" finds the right concept.
> > 
> > So you're saying change dart.bind to both bind the function and add rtti and
> > then just use that?  That's fine by me.  
> 
> err, I think so :). What do we still use "dart.bind" for after your CL?

Apparently nothing.  Made the switch.

[Leaf, 2015-05-20 18:13:42]

Committed patchset #3 (id:40001) manually as
3f47a80af77a37420e5e5907685a2497cb23c996 (presubmit successful).