Make type canonicalization thread safe

Make type canonicalization thread safe

BUG=
R=asiva@google.com

Committed: https://github.com/dart-lang/sdk/commit/88acc8ab01207764b9c8cf2f18524e27be75e1bb

[srdjan, 2016-03-01 00:47:52]

srdjan@google.com changed reviewers:
+ asiva@google.com

[siva, 2016-03-01 16:57:40]

lgtm

https://codereview.chromium.org/1747073002/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/1747073002/diff/1/runtime/vm/object.cc#newcod...
runtime/vm/object.cc:4160: }
Should we hoist the while loop as a helper method 
RawType* LookupType(const Array& canonical_types);

and then we could do

canonical_types ^= this->canonical_types();
type^ = LookupType(canonical_types);
if (!type.IsNull()) {
  return type.raw();
}
{
 Lock...
 ....
 canonical_types ^= ...;
 type ^= LookupType(canonical_types);
 if (!type.IsNull()) {
   return type.raw();
 }
 lookup_type.SetCanonical();
 ...
 ...
}

[srdjan, 2016-03-01 19:28:13]

https://codereview.chromium.org/1747073002/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/1747073002/diff/1/runtime/vm/object.cc#newcod...
runtime/vm/object.cc:4160: }
On 2016/03/01 16:57:40, siva wrote:
> Should we hoist the while loop as a helper method 
> RawType* LookupType(const Array& canonical_types);
> 
> and then we could do
> 
> canonical_types ^= this->canonical_types();
> type^ = LookupType(canonical_types);
> if (!type.IsNull()) {
>   return type.raw();
> }
> {
>  Lock...
>  ....
>  canonical_types ^= ...;
>  type ^= LookupType(canonical_types);
>  if (!type.IsNull()) {
>    return type.raw();
>  }
>  lookup_type.SetCanonical();
>  ...
>  ...
> }

Done.

[srdjan, 2016-03-01 20:12:20]

Description was changed from

==========
Make type canonicalization thread safe

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

to

==========
Make type canonicalization thread safe

BUG=
R=asiva@google.com

Committed:
https://github.com/dart-lang/sdk/commit/88acc8ab01207764b9c8cf2f18524e27be75e1bb
==========

[srdjan, 2016-03-01 20:12:23]

Committed patchset #2 (id:20001) manually as
88acc8ab01207764b9c8cf2f18524e27be75e1bb (presubmit successful).