Added a run state field to Isolate

Added a run state field to Isolate, to show when it is executing code.

Committed: https://code.google.com/p/dart/source/detail?r=21561

[Ivan Posva, 2013-04-12 21:23:03]

First round of comments.

-Ivan

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h
File runtime/vm/isolate.h (right):

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:276: enum {
Please name this enum.

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:277: kIsolateWaiting = 0x1,       // The isolate is waiting
for code to execute.
= 0

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:278: kIsolateRunning = 0x2,       // The isolate is
executing code.
We do not necessarily care about this absolute value, so just let it sit empty.

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:293: uword running_state() const { return running_state_; }
Once the enum is name we do not have to pass uwords for the state.

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:502: bool is_runnable_;
What is the difference to this field? Shouldn't they be combined?

[Tom Ball, 2013-04-12 21:56:46]

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h
File runtime/vm/isolate.h (right):

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:276: enum {
On 2013/04/12 21:23:03, Ivan Posva wrote:
> Please name this enum.

Done.

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:277: kIsolateWaiting = 0x1,       // The isolate is waiting
for code to execute.
On 2013/04/12 21:23:03, Ivan Posva wrote:
> = 0

Done.

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:278: kIsolateRunning = 0x2,       // The isolate is
executing code.
On 2013/04/12 21:23:03, Ivan Posva wrote:
> We do not necessarily care about this absolute value, so just let it sit
empty.

Done.

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:293: uword running_state() const { return running_state_; }
On 2013/04/12 21:23:03, Ivan Posva wrote:
> Once the enum is name we do not have to pass uwords for the state.

Done.

https://codereview.chromium.org/13932024/diff/5001/runtime/vm/isolate.h#newco...
runtime/vm/isolate.h:502: bool is_runnable_;
On 2013/04/12 21:23:03, Ivan Posva wrote:
> What is the difference to this field? Shouldn't they be combined?

I found that a client can invoke multiple functions in a single isolate, so I
thought it clearer for runnable to mean that it is valid to invoke a function in
an isolate, and run_state_ to indicate whether it's currently executing a
function. I can combine the two fields if you'd rather, though.

[Ivan Posva, 2013-04-16 17:29:34]

As long as we consider this as a hint to other areas of the VM, this is fine. It
is never going to be a 100% correct value due to concurrent access.

Apart from that LGTM.

-Ivan

[Tom Ball, 2013-04-16 17:50:30]

Committed patchset #3 manually as r21561 (presubmit successful).