[wasm] explicitly mark off unlinked wasm module instances

[wasm] explicitly mark off unlinked wasm module instances

This fixes a gc stress bug. We cannot rely on an ordering of
clearing of the weak cells, so we explicitly reset the weak
link to the owning instance, when finalizing a compiled
module. In turn, this serves as a reliable signal when GCs
happen while instantiating, allowing us to correctly link the
new instance.

BUG=chromium:652425
Committed: https://crrev.com/c938f0df224b49d805503bbad98c4180f014e11a
Cr-Commit-Position: refs/heads/master@{#39964}

[Mircea Trofin, 2016-10-04 16:20:54]

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

[commit-bot: I haz the power, 2016-10-04 16:20:57]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-04 16:24:47]

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

[commit-bot: I haz the power, 2016-10-04 16:24:48]

Dry run: Try jobs failed on following builders:
  v8_linux64_gyp_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_gyp_rel_ng/build...)
  v8_linux_mipsel_compile_rel on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_mipsel_compile_rel...)

[Mircea Trofin, 2016-10-04 19:20:14]

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

[commit-bot: I haz the power, 2016-10-04 19:20:22]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Mircea Trofin, 2016-10-04 19:21:22]

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

[commit-bot: I haz the power, 2016-10-04 19:21:30]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Mircea Trofin, 2016-10-04 19:35:03]

Patchset #1 (id:1) has been deleted

[Mircea Trofin, 2016-10-04 19:35:45]

Description was changed from

==========
[wasm] explicitly mark off unlinked wasm module instances

This fixes a gc stress bug. In addition, the CL introduces a simple
tracing mechanism for wasm instantiation and finalization, and a
debug-time unique instance identifier.

BUG=chromium:652425
==========

to

==========
[wasm] explicitly mark off unlinked wasm module instances

This fixes a gc stress bug. In addition, the CL introduces a simple
tracing mechanism for wasm instantiation and finalization, and a
debug-time unique instance identifier.

BUG=chromium:652425
==========

[Mircea Trofin, 2016-10-04 19:35:45]

mtrofin@chromium.org changed reviewers:
+ bradnelson@chromium.org

[commit-bot: I haz the power, 2016-10-04 19:55:43]

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

[commit-bot: I haz the power, 2016-10-04 19:55:44]

Dry run: This issue passed the CQ dry run.

[Mircea Trofin, 2016-10-04 20:11:00]

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

[commit-bot: I haz the power, 2016-10-04 20:11:07]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Mircea Trofin, 2016-10-04 20:15:48]

Description was changed from

==========
[wasm] explicitly mark off unlinked wasm module instances

This fixes a gc stress bug. In addition, the CL introduces a simple
tracing mechanism for wasm instantiation and finalization, and a
debug-time unique instance identifier.

BUG=chromium:652425
==========

to

==========
[wasm] explicitly mark off unlinked wasm module instances

This fixes a gc stress bug. We cannot rely on an ordering of
clearing of the weak cells, so we explicitly reset the weak
link to the owning instance, when finalizing a compiled 
module. In turn, this serves as a reliable signal when GCs
happen while instantiating, allowing us to correctly link the
new instance.

BUG=chromium:652425
==========

[commit-bot: I haz the power, 2016-10-04 20:23:17]

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

[commit-bot: I haz the power, 2016-10-04 20:23:18]

Dry run: Try jobs failed on following builders:
  v8_linux64_asan_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_asan_rel_ng/buil...)
  v8_linux64_asan_rel_ng_triggered on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_asan_rel_ng_trig...)

[Mircea Trofin, 2016-10-04 20:52:26]

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

[commit-bot: I haz the power, 2016-10-04 20:52:34]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-04 21:18:04]

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

[commit-bot: I haz the power, 2016-10-04 21:18:05]

Dry run: This issue passed the CQ dry run.

[bradnelson, 2016-10-04 21:18:36]

The CQ bit was checked by bradnelson@chromium.org

[bradnelson, 2016-10-04 21:18:36]

lgtm

[commit-bot: I haz the power, 2016-10-04 21:18:45]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-04 21:23:10]

Description was changed from

==========
[wasm] explicitly mark off unlinked wasm module instances

This fixes a gc stress bug. We cannot rely on an ordering of
clearing of the weak cells, so we explicitly reset the weak
link to the owning instance, when finalizing a compiled 
module. In turn, this serves as a reliable signal when GCs
happen while instantiating, allowing us to correctly link the
new instance.

BUG=chromium:652425
==========

to

==========
[wasm] explicitly mark off unlinked wasm module instances

This fixes a gc stress bug. We cannot rely on an ordering of
clearing of the weak cells, so we explicitly reset the weak
link to the owning instance, when finalizing a compiled 
module. In turn, this serves as a reliable signal when GCs
happen while instantiating, allowing us to correctly link the
new instance.

BUG=chromium:652425
==========

[commit-bot: I haz the power, 2016-10-04 21:23:11]

Committed patchset #4 (id:80001)

[commit-bot: I haz the power, 2016-10-04 21:23:30]

Description was changed from

==========
[wasm] explicitly mark off unlinked wasm module instances

This fixes a gc stress bug. We cannot rely on an ordering of
clearing of the weak cells, so we explicitly reset the weak
link to the owning instance, when finalizing a compiled 
module. In turn, this serves as a reliable signal when GCs
happen while instantiating, allowing us to correctly link the
new instance.

BUG=chromium:652425
==========

to

==========
[wasm] explicitly mark off unlinked wasm module instances

This fixes a gc stress bug. We cannot rely on an ordering of
clearing of the weak cells, so we explicitly reset the weak
link to the owning instance, when finalizing a compiled
module. In turn, this serves as a reliable signal when GCs
happen while instantiating, allowing us to correctly link the
new instance.

BUG=chromium:652425

Committed: https://crrev.com/c938f0df224b49d805503bbad98c4180f014e11a
Cr-Commit-Position: refs/heads/master@{#39964}
==========

[commit-bot: I haz the power, 2016-10-04 21:23:31]

Patchset 4 (id:??) landed as
https://crrev.com/c938f0df224b49d805503bbad98c4180f014e11a
Cr-Commit-Position: refs/heads/master@{#39964}