Add option for outputting a deferred loading mapping.

Add option for outputting a deferred loading mapping.

With the option --deferred-map=<file> dart2js will output a json-file
describing which files will get loaded for a given deferred import.

The output looks like:
{
  "_comment": "This mapping shows which compiled `.js` files are needed for a given deferred library import.",
  "main.dart": {
    "name": "mainLibrary",
    "imports": {
      "lib1": [
        "out.js_2.part.js",
        "out.js_1.part.js"
      ],
      "lib2": [
        "out.js_2.part.js",
        "out.js_3.part.js"
      ],
      "lib3": [
        "out.js_5.part.js"
      ],
      "lib4": [
        "out.js_6.part.js"
      ]
    }
  },
  "lib1.dart": {
    "name": "<unnamed>",
    "imports": {
      "convert": [
        "out.js_4.part.js"
      ]
    }
  }
}
BUG=dartbug.com/21869
R=floitsch@google.com

Committed: https://code.google.com/p/dart/source/detail?r=42727

[sigurdm, 2015-01-05 13:59:51]

sigurdm@google.com changed reviewers:
+ floitsch@google.com, johnniwinther@google.com

[floitsch, 2015-01-05 14:10:39]

LGTM.
I think this information should also be part of --dump-info. Another CL?

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/def...
File pkg/compiler/lib/src/deferred_load.dart (right):

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:778: Map deferredMap() {
has a getter name.
Either make it a getter, or change the name.

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:784: Map a =
mapping.putIfAbsent(description.importingUri, () => {});
what's "a" ?
Type the map (both static and dynamic).

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:788: return
backend.emitter.oldEmitter.deferredPartFileName(outputUnit);
Don't go through "oldEmitter".
The best is probably currently to add a "emitter.deferredPartFileName" to the
emitter task. That said, it could be shared code. (Currently it is duplicated by
copy/paste).

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/js_...
File pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart (right):

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/js_...
pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart:2278: Map mapping = new
Map();
types.

[sigurdm, 2015-01-05 15:23:08]

Yes, I planned to add it to dump-info in a second CL.

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/def...
File pkg/compiler/lib/src/deferred_load.dart (right):

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:778: Map deferredMap() {
On 2015/01/05 14:10:38, floitsch wrote:
> has a getter name.
> Either make it a getter, or change the name.

Done.

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:784: Map a =
mapping.putIfAbsent(description.importingUri, () => {});
On 2015/01/05 14:10:38, floitsch wrote:
> what's "a" ?
Fixed the name.
> Type the map (both static and dynamic).

Done.

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:788: return
backend.emitter.oldEmitter.deferredPartFileName(outputUnit);
On 2015/01/05 14:10:38, floitsch wrote:
> Don't go through "oldEmitter".
> The best is probably currently to add a "emitter.deferredPartFileName" to the
> emitter task. That said, it could be shared code. (Currently it is duplicated
by
> copy/paste).
Moved it to backend.

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/js_...
File pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart (right):

https://codereview.chromium.org/785303003/diff/40001/pkg/compiler/lib/src/js_...
pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart:2278: Map mapping = new
Map();
On 2015/01/05 14:10:38, floitsch wrote:
> types.

I changed it to Map<String, dynamic> If we want the comment to stay, then it
cannot get more precise.

[sigurdm, 2015-01-05 15:24:08]

PTAL

[floitsch, 2015-01-05 15:46:19]

LGTM.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
File pkg/compiler/lib/src/deferred_load.dart (right):

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:777: /// given deferred import.
Add comment what the keys and values are.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:778: Map<String, Map<String,
List<String>>> getDeferredMap() {
'getX' doesn't say why this is not a getter.
computeDeferredMap is not much better, but makes it clear that the call we
create the map.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:780: Map<String, Map<String,
List<String>>> mapping =
Now I understand why you didn't add the types...

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:791: return
backend.outputFileName("${outputUnit.name}.part.js");
Don't add the extension here.
Ask for the deferredPartFileName on backend.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
File pkg/compiler/lib/src/js_backend/backend.dart (right):

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
pkg/compiler/lib/src/js_backend/backend.dart:2311: /// Returns a name composed
of the main output file name and [name].
Not your comment, but:
That describes what it does, but not how it should be used.
I also don't think that it needs to do that.

Maybe:
Returns a unique filename for [name].

The given [name] should have an extension (if necessary).


That said: I guess it would be nice, if it took an optional extension argument.
(if that's how the function is used most often).

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
File pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart (right):

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart:2084:
uris.add(backend.outputFileName("${outputUnit.name}.part.js"));
no. backend.deferredPartFileName(...)

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart:2263: Map<String,
dynamic> mapping = new Map();
new Map<String, dynamic>

[sigurdm, 2015-01-06 09:02:20]

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
File pkg/compiler/lib/src/deferred_load.dart (right):

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:777: /// given deferred import.
On 2015/01/05 15:46:19, floitsch wrote:
> Add comment what the keys and values are.

Done.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:778: Map<String, Map<String,
List<String>>> getDeferredMap() {
On 2015/01/05 15:46:19, floitsch wrote:
> 'getX' doesn't say why this is not a getter.
> computeDeferredMap is not much better, but makes it clear that the call we
> create the map.

Done.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:780: Map<String, Map<String,
List<String>>> mapping =
On 2015/01/05 15:46:19, floitsch wrote:
> Now I understand why you didn't add the types...

First the map had a different structure that could not be typed. Then I forgot
to add them back.
But they are indeed horrid.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/def...
pkg/compiler/lib/src/deferred_load.dart:791: return
backend.outputFileName("${outputUnit.name}.part.js");
On 2015/01/05 15:46:19, floitsch wrote:
> Don't add the extension here.
> Ask for the deferredPartFileName on backend.

Done.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
File pkg/compiler/lib/src/js_backend/backend.dart (right):

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
pkg/compiler/lib/src/js_backend/backend.dart:2311: /// Returns a name composed
of the main output file name and [name].
On 2015/01/05 15:46:19, floitsch wrote:
> Not your comment, but:
> That describes what it does, but not how it should be used.
> I also don't think that it needs to do that.
> 
> Maybe:
> Returns a unique filename for [name].
> 
> The given [name] should have an extension (if necessary).
> 
> 
> That said: I guess it would be nice, if it took an optional extension
argument.
> (if that's how the function is used most often).

Done.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
File pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart (right):

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart:2084:
uris.add(backend.outputFileName("${outputUnit.name}.part.js"));
On 2015/01/05 15:46:19, floitsch wrote:
> no. backend.deferredPartFileName(...)

Done.

https://codereview.chromium.org/785303003/diff/60001/pkg/compiler/lib/src/js_...
pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart:2263: Map<String,
dynamic> mapping = new Map();
On 2015/01/05 15:46:19, floitsch wrote:
> new Map<String, dynamic>

Done.

[sigurdm, 2015-01-08 12:38:42]

I updated the format.
PTAL

[floitsch, 2015-01-08 13:41:08]

LGTM.

https://codereview.chromium.org/785303003/diff/100001/pkg/compiler/lib/src/de...
File pkg/compiler/lib/src/deferred_load.dart (right):

https://codereview.chromium.org/785303003/diff/100001/pkg/compiler/lib/src/de...
pkg/compiler/lib/src/deferred_load.dart:780: /// Where
Please check if this goes nicely in markdown. (maybe you need new lines
somewhere).

https://codereview.chromium.org/785303003/diff/100001/pkg/compiler/lib/src/js...
File pkg/compiler/lib/src/js_backend/backend.dart (right):

https://codereview.chromium.org/785303003/diff/100001/pkg/compiler/lib/src/js...
pkg/compiler/lib/src/js_backend/backend.dart:2312: /// The filename is of the
form "<main output file>_<name>.part.js".
Probably needs a new line before.

Ok. But now it is fixed (which might not be bad).

[sigurdm, 2015-01-09 10:16:55]

https://codereview.chromium.org/785303003/diff/100001/pkg/compiler/lib/src/de...
File pkg/compiler/lib/src/deferred_load.dart (right):

https://codereview.chromium.org/785303003/diff/100001/pkg/compiler/lib/src/de...
pkg/compiler/lib/src/deferred_load.dart:780: /// Where
On 2015/01/08 13:41:07, floitsch wrote:
> Please check if this goes nicely in markdown. (maybe you need new lines
> somewhere).

Done. Inserted a newline

https://codereview.chromium.org/785303003/diff/100001/pkg/compiler/lib/src/js...
File pkg/compiler/lib/src/js_backend/backend.dart (right):

https://codereview.chromium.org/785303003/diff/100001/pkg/compiler/lib/src/js...
pkg/compiler/lib/src/js_backend/backend.dart:2312: /// The filename is of the
form "<main output file>_<name>.part.js".
On 2015/01/08 13:41:07, floitsch wrote:
> Probably needs a new line before.
> 
> Ok. But now it is fixed (which might not be bad).

Done.

[sigurdm, 2015-01-09 10:37:15]

Committed patchset #8 (id:140001) manually as 42727 (presubmit successful).