dart2js: compute the currentScript in the preamble for d8 and jsshell.

dart2js: compute the currentScript in the preamble for d8 and jsshell.

This change enables deferred loading for the lazy emitter on d8. Without it the computeThisScript function would be executed within an 'evaled' piece of code, and thus not find the correct URL.

This change also reduces the code of the generated code (by a tiny amount),

R=herhut@google.com

Committed: https://code.google.com/p/dart/source/detail?r=45671

[floitsch, 2015-05-07 21:09:51]

floitsch@google.com changed reviewers:
+ sra@google.com

[floitsch, 2015-05-07 21:09:51]

https://codereview.chromium.org/1130293002/diff/1/sdk/lib/_internal/compiler/...
File sdk/lib/_internal/compiler/js_lib/isolate_helper.dart (right):

https://codereview.chromium.org/1130293002/diff/1/sdk/lib/_internal/compiler/...
sdk/lib/_internal/compiler/js_lib/isolate_helper.dart:761: var currentScript =
JS_EMBEDDED_GLOBAL('', CURRENT_SCRIPT);
The embedded global is set, if `document.currentScript` was found at init-time.

[herhut, 2015-05-08 08:06:27]

herhut@google.com changed reviewers:
+ herhut@google.com

[herhut, 2015-05-08 08:06:27]

lgtm

https://codereview.chromium.org/1130293002/diff/1/sdk/lib/_internal/compiler/...
File sdk/lib/_internal/compiler/js_lib/isolate_helper.dart (left):

https://codereview.chromium.org/1130293002/diff/1/sdk/lib/_internal/compiler/...
sdk/lib/_internal/compiler/js_lib/isolate_helper.dart:764: if (Primitives.isD8)
return computeThisScriptD8();
Do we still need the Primitives.isXX helpers? It would be great to get rid of
them if possible.

[floitsch, 2015-05-09 00:59:31]

Committed patchset #1 (id:1) manually as 45671 (presubmit successful).

[floitsch, 2015-05-09 01:07:54]

https://codereview.chromium.org/1130293002/diff/1/sdk/lib/_internal/compiler/...
File sdk/lib/_internal/compiler/js_lib/isolate_helper.dart (left):

https://codereview.chromium.org/1130293002/diff/1/sdk/lib/_internal/compiler/...
sdk/lib/_internal/compiler/js_lib/isolate_helper.dart:764: if (Primitives.isD8)
return computeThisScriptD8();
On 2015/05/08 08:06:27, herhut wrote:
> Do we still need the Primitives.isXX helpers? It would be great to get rid of
> them if possible.

Removed in https://codereview.chromium.org/1132923002/

[sra1, 2015-05-11 16:35:06]

lgtm.

If the stack trace string format changes, is there a test that fails that makes
it obvious that this is the problem?

[floitsch, 2015-05-12 00:21:46]

On 2015/05/11 16:35:06, sra1 wrote:
> lgtm.
> 
> If the stack trace string format changes, is there a test that fails that
makes
> it obvious that this is the problem?

All deferred library tests would fail (and an additional test would likely
drown).
However, if the format changes, it is also very likely that the regexp wouldn't
match anymore, and that you would get a null-pointer exception in the return:
'return lastMatch[1]'.