VM: Fix an app-jit related shutdown race.

VM: Fix an app-jit related shutdown race.

IsolateData contains AppSnapshot which might own some HeapPage-s, so we can't
destroy IsolateData in the Dart_IsolateShutdownCallback, because some thread
running in the isolate (e.g. background compiler) might still touch
thoses pages or objects they host.

We need to delay destruction of AppSnapshot until after the isolate shutdown.

Current API does not allow that, so we introduce a new isolate lifecycle
callback - Dart_IsolateCleanupCallback, which is invoked at the end of the
isolote lifecycle when things like background compiler have been stopped
and no Dart code is supposed to run.

BUG=
R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/a5e1f89583d5986e32b4a60181f04e534179d7d1

[Vyacheslav Egorov (Google), 2017-02-28 15:35:09]

vegorov@google.com changed reviewers:
+ rmacnak@google.com

[Vyacheslav Egorov (Google), 2017-02-28 15:35:09]

Hi Ryan! Please take a look. 

With this CL and the one related to snapshot features we are able to run almost
the whole co19/kernel/language suites through kernel-isolate&app-jit snapshot:

[07:24 | 100% | +12797 | -    3]

(and it is much faster then without appjit snapshot! hooray!)

I am looking at the last failure which seems to be a bug in the optimizer,
because it is triggered with some special options.

[rmacnak, 2017-02-28 17:46:16]

lgtm

This affects app-aot as well, since it potentially touches the released pages
during shutdown. It only affects the standalone embedder because Flutter
currently leaks the snapshot.

[Vyacheslav Egorov (Google), 2017-02-28 20:10:08]

Description was changed from

==========
VM: Fix an app-jit related shutdown race.

IsolateData contains AppSnapshot which might own some HeapPage-s, so we can't
destroy IsolateData in the Dart_IsolateShutdownCallback, because some thread
running in the isolate (e.g. background compiler) might still touch
thoses pages or objects they host.

We need to delay destruction of AppSnapshot until after the isolate shutdown.

Current API does not allow that, so we introduce a new isolate lifecycle
callback - Dart_IsolateCleanupCallback, which is invoked at the end of the
isolote lifecycle when things like background compiler have been stopped
and no Dart code is supposed to run.

BUG=
==========

to

==========
VM: Fix an app-jit related shutdown race.

IsolateData contains AppSnapshot which might own some HeapPage-s, so we can't
destroy IsolateData in the Dart_IsolateShutdownCallback, because some thread
running in the isolate (e.g. background compiler) might still touch
thoses pages or objects they host.

We need to delay destruction of AppSnapshot until after the isolate shutdown.

Current API does not allow that, so we introduce a new isolate lifecycle
callback - Dart_IsolateCleanupCallback, which is invoked at the end of the
isolote lifecycle when things like background compiler have been stopped
and no Dart code is supposed to run.

BUG=
R=rmacnak@google.com

Committed:
https://github.com/dart-lang/sdk/commit/a5e1f89583d5986e32b4a60181f04e534179d7d1
==========

[Vyacheslav Egorov (Google), 2017-02-28 20:10:09]

Committed patchset #1 (id:1) manually as
a5e1f89583d5986e32b4a60181f04e534179d7d1 (presubmit successful).