Fix duplication of the megamorphic miss function when running a JIT app snapshot.

Fix duplication of the megamorphic miss function when running a JIT app snapshot.

1a41627eccfea79cb440924e25a6601e003e56d7 caused isolate start up to incorrectly create a second megamorphic miss function when running from a JIT app snapshot. These caused the code for the one from the snapshot to be collected, and the parser to fail attempting to recompile it.

Fixes #28200

R=asiva@google.com

Committed: https://github.com/dart-lang/sdk/commit/9c1702d38a396779045f33a14bea11431b4034cd

[rmacnak, 2017-01-05 22:55:45]

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

[siva, 2017-01-05 23:10:47]

lgtm with one comment.

https://codereview.chromium.org/2616763003/diff/1/runtime/vm/dart.cc
File runtime/vm/dart.cc (right):

https://codereview.chromium.org/2616763003/diff/1/runtime/vm/dart.cc#newcode585
runtime/vm/dart.cc:585: // snapshot.
The comment here also probably needs an update
(precompiled and running from an application snapshot) ?

https://codereview.chromium.org/2616763003/diff/1/runtime/vm/dart.cc#newcode589
runtime/vm/dart.cc:589: #endif
Should this be set up as

#if defined(DART_PRECOMPILED_RUNTIME)
   // When running precompiled, the megamorphic mi.....
   ASSERT(I->object_store()->megamorphic_miss_function() != Function::null());
#else
   // When running from an application snapshot ....
   if (I->object_store()->megamorphic_miss_function() == Function...) {
      ....
    }
#endif  // defined(DART_PRECOMPILED_RUNTIME)

[rmacnak, 2017-01-05 23:32:44]

https://codereview.chromium.org/2616763003/diff/1/runtime/vm/dart.cc
File runtime/vm/dart.cc (right):

https://codereview.chromium.org/2616763003/diff/1/runtime/vm/dart.cc#newcode585
runtime/vm/dart.cc:585: // snapshot.
On 2017/01/05 23:10:47, siva wrote:
> The comment here also probably needs an update
> (precompiled and running from an application snapshot) ?

Done.

https://codereview.chromium.org/2616763003/diff/1/runtime/vm/dart.cc#newcode589
runtime/vm/dart.cc:589: #endif
On 2017/01/05 23:10:47, siva wrote:
> Should this be set up as
> 
> #if defined(DART_PRECOMPILED_RUNTIME)
>    // When running precompiled, the megamorphic mi.....
>    ASSERT(I->object_store()->megamorphic_miss_function() != Function::null());
> #else
>    // When running from an application snapshot ....
>    if (I->object_store()->megamorphic_miss_function() == Function...) {
>       ....
>     }
> #endif  // defined(DART_PRECOMPILED_RUNTIME)

Done.

[rmacnak, 2017-01-05 23:34:09]

Description was changed from

==========
Fix duplication of the megamorphic miss function when running a JIT app
snapshot.

1a41627eccfea79cb440924e25a6601e003e56d7 caused isolate start up to incorrectly
create a second megamorphic miss function when running from a JIT app snapshot.
These caused the code for the one from the snapshot to be collected, and the
parser to fail attempting to recompile it.

Fixes #28200
==========

to

==========
Fix duplication of the megamorphic miss function when running a JIT app
snapshot.

1a41627eccfea79cb440924e25a6601e003e56d7 caused isolate start up to incorrectly
create a second megamorphic miss function when running from a JIT app snapshot.
These caused the code for the one from the snapshot to be collected, and the
parser to fail attempting to recompile it.

Fixes #28200

R=asiva@google.com

Committed:
https://github.com/dart-lang/sdk/commit/9c1702d38a396779045f33a14bea11431b4034cd
==========

[rmacnak, 2017-01-05 23:34:10]

Committed patchset #2 (id:20001) manually as
9c1702d38a396779045f33a14bea11431b4034cd (presubmit successful).