VM: Fix source location in stack trace of async code.

VM: Fix source location in stack trace of async code.

This eliminates an invalid source position and allows async code
to work with the stack_traces package to a get full async stack chain.

Frames with an invalid location (file.dart:1:1) are now printed without
line/column information (file.dart)

BUG=dartbug.com/22009
R=iposva@google.com

Committed: https://code.google.com/p/dart/source/detail?r=43497

[Florian Schneider, 2015-02-04 17:19:47]

fschneider@google.com changed reviewers:
+ iposva@google.com, zerny@google.com

[Ivan Posva, 2015-02-04 18:13:29]

LGTM -ip

[hausner, 2015-02-04 18:34:12]

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

[hausner, 2015-02-04 18:34:13]

DBC

https://codereview.chromium.org/904443002/diff/40001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/904443002/diff/40001/runtime/vm/object.cc#new...
runtime/vm/object.cc:20152: } else if (line >= 0) {
I believe line is always >= 0 (> 0 actually). GetTokenLocation() gets called for
even for token_pos == Scanner::kNoSourcePos (== 0) and sets the line number to
at least 1.

[Ivan Posva, 2015-02-04 21:15:29]

Missed this one earlier. -ip

https://codereview.chromium.org/904443002/diff/40001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/904443002/diff/40001/runtime/vm/object.cc#new...
runtime/vm/object.cc:20134: if (token_pos >= 0) {
(token_pos > 0)

[Florian Schneider, 2015-02-05 09:55:19]

New patchsets have been uploaded after l-g-t-m from iposva@google.com

[Florian Schneider, 2015-02-05 09:55:43]

https://codereview.chromium.org/904443002/diff/40001/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/904443002/diff/40001/runtime/vm/object.cc#new...
runtime/vm/object.cc:20134: if (token_pos >= 0) {
On 2015/02/04 21:15:29, Ivan Posva wrote:
> (token_pos > 0)

Done.

https://codereview.chromium.org/904443002/diff/40001/runtime/vm/object.cc#new...
runtime/vm/object.cc:20152: } else if (line >= 0) {
On 2015/02/04 18:34:13, hausner wrote:
> I believe line is always >= 0 (> 0 actually). GetTokenLocation() gets called
for
> even for token_pos == Scanner::kNoSourcePos (== 0) and sets the line number to
> at least 1.

Oh yes, forgot to check that token_pos > 0 above.

[Florian Schneider, 2015-02-05 10:26:32]

Committed patchset #5 (id:80001) manually as r43497 (presubmit successful).