[debug] implement intuitive semantics for stepping over await call.

[debug] implement intuitive semantics for stepping over await call.

R=*bmeurer@chromium.org, caitpotter88@gmail.com, *littledan@chromium.org, *ulan@chromium.org
BUG=v8:4483
Committed: https://crrev.com/8d90210a1e68b141b1b2345b7b898f6920df3a3d
Cr-Commit-Position: refs/heads/master@{#36718}

[Yang, 2016-06-03 09:23:52]

Please take a look.

I'll write platform ports once this is otherwise ready.

[Benedikt Meurer, 2016-06-03 09:26:59]

LGTM from my side.

[ulan, 2016-06-03 09:33:50]

heap lgtm.

https://codereview.chromium.org/2033223003/diff/1/src/debug/debug.cc
File src/debug/debug.cc (right):

https://codereview.chromium.org/2033223003/diff/1/src/debug/debug.cc#newcode505
src/debug/debug.cc:505: v->VisitPointer(&thread_local_.suspended_generator_);
Please guard it with
if (thread_local_.suspended_generator_ != nullptr)

to make it explicit when the pointer is valid and to not implicitly rely on
nullptr == Smi(0).

[Yang, 2016-06-03 11:48:11]

https://codereview.chromium.org/2033223003/diff/1/src/debug/debug.cc
File src/debug/debug.cc (right):

https://codereview.chromium.org/2033223003/diff/1/src/debug/debug.cc#newcode505
src/debug/debug.cc:505: v->VisitPointer(&thread_local_.suspended_generator_);
On 2016/06/03 09:33:50, ulan wrote:
> Please guard it with
> if (thread_local_.suspended_generator_ != nullptr)
> 
> to make it explicit when the pointer is valid and to not implicitly rely on
> nullptr == Smi(0).

Done.

[Yang, 2016-06-03 11:48:17]

The CQ bit was checked by yangguo@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-06-03 11:48:22]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2033223003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2033223003/40001

[Yang, 2016-06-03 11:48:29]

Platform ports are done.

[commit-bot: I haz the power, 2016-06-03 12:27:52]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-06-03 12:27:53]

Dry run: Try jobs failed on following builders:
  v8_linux_arm64_rel_ng on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel_ng/build...)
  v8_linux_arm64_rel_ng_triggered on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel_ng_trigg...)

[Dan Ehrenberg, 2016-06-03 12:56:16]

lgtm

Parser changes lgtm

https://codereview.chromium.org/2033223003/diff/40001/src/parsing/parser.cc
File src/parsing/parser.cc (right):

https://codereview.chromium.org/2033223003/diff/40001/src/parsing/parser.cc#n...
src/parsing/parser.cc:5623: zone());
To confirm my understanding, you needed to put this in a do expression in order
to get a breakpoint, right? Even though the assignment has a position, that is
not enough?

[Yang, 2016-06-03 15:01:10]

https://codereview.chromium.org/2033223003/diff/40001/src/parsing/parser.cc
File src/parsing/parser.cc (right):

https://codereview.chromium.org/2033223003/diff/40001/src/parsing/parser.cc#n...
src/parsing/parser.cc:5623: zone());
On 2016/06/03 12:56:16, Dan Ehrenberg wrote:
> To confirm my understanding, you needed to put this in a do expression in
order
> to get a breakpoint, right? Even though the assignment has a position, that is
> not enough?

The assignment is just an expression, not a statement. What I need however is
for it to be a statement so that it includes a break location. The assignment
also has to be done before the yield expression, which is not the case if the
value expression is an argument to async_function_await, which is an argument to
yield.

The alternative to this is to add a flag to the yield expression and emit
statement positions based on that in the code generator. But that's messy and
will need to be ported to every platform (including interpreter bytecode).

[Yang, 2016-06-03 15:01:53]

The CQ bit was checked by yangguo@chromium.org

[Yang, 2016-06-03 15:01:54]

The patchset sent to the CQ was uploaded after l-g-t-m from
bmeurer@chromium.org, ulan@chromium.org, littledan@chromium.org
Link to the patchset: https://codereview.chromium.org/2033223003/#ps60001
(title: "fix arm64")

[commit-bot: I haz the power, 2016-06-03 15:02:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2033223003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2033223003/60001

[commit-bot: I haz the power, 2016-06-03 15:30:52]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-06-03 15:32:01]

Description was changed from

==========
[debug] implement intuitive semantics for stepping over await call.

R=*bmeurer@chromium.org, caitpotter88@gmail.com, *littledan@chromium.org,
*ulan@chromium.org
BUG=v8:4483
==========

to

==========
[debug] implement intuitive semantics for stepping over await call.

R=*bmeurer@chromium.org, caitpotter88@gmail.com, *littledan@chromium.org,
*ulan@chromium.org
BUG=v8:4483

Committed: https://crrev.com/8d90210a1e68b141b1b2345b7b898f6920df3a3d
Cr-Commit-Position: refs/heads/master@{#36718}
==========

[commit-bot: I haz the power, 2016-06-03 15:32:02]

Patchset 4 (id:??) landed as
https://crrev.com/8d90210a1e68b141b1b2345b7b898f6920df3a3d
Cr-Commit-Position: refs/heads/master@{#36718}