[kernel] Fix getter, run service tests in debug mode

[kernel] Fix getter, run service tests in debug mode

Don't create getters for uninitialized static fields.
This fixes two assert hits that was hit when running service tests in debug mode via kernel. These can thus now be enabled.

BUG=
R=kmillikin@google.com

Committed: https://github.com/dart-lang/sdk/commit/dc566e137b7e1765f6615410a07e120230eaccf4

[jensj, 2017-03-22 11:49:01]

jensj@google.com changed reviewers:
+ kmillikin@google.com

[jensj, 2017-03-22 11:49:01]

2 tests fail in debug mode without removing the assert.
Can easily reproduce by hand:
```dart
var global;

void warmup() {
  global = [42];
}

void main() {
  warmup();
  print(global);
}
```
debug build, run with kernel, debug with observatory, breakpoint on print line,
type "p global" and enter in the "command box thingy", and it will crash,
hitting the assert.

Alternatively we can leave the assert and update the status file to allow the 2
service tests developer_service_get_isolate_id_test and get_instances_rpc_test
to fail in kernel debug mode...

[Kevin Millikin (Google), 2017-03-22 13:09:38]

https://codereview.chromium.org/2771443003/diff/1/runtime/vm/kernel_to_il.cc
File runtime/vm/kernel_to_il.cc (left):

https://codereview.chromium.org/2771443003/diff/1/runtime/vm/kernel_to_il.cc#...
runtime/vm/kernel_to_il.cc:3554: ASSERT(field.has_initializer());
I think the ASSERT is indicating that something is not behaving the way we
expect.

The fix is probably to add this at the beginning of
KernelReader::GenerateFieldAccessors:

  if (kernel_field->IsStatic() && kernel_field->initializer() == NULL) {
    field.SetStaticValue(Instance::Handle(Z), true);
    return;
  }

[jensj, 2017-03-22 13:22:45]

Yep, that works.

[Kevin Millikin (Google), 2017-03-22 14:11:26]

LGTM but add a comment explaining why we intend the early return in that case.

https://codereview.chromium.org/2771443003/diff/20001/runtime/vm/kernel_reade...
File runtime/vm/kernel_reader.cc (right):

https://codereview.chromium.org/2771443003/diff/20001/runtime/vm/kernel_reade...
runtime/vm/kernel_reader.cc:566: field.SetStaticValue(Instance::Handle(Z),
true);
Comment:

// Static fields without an initializer are implicitly initialized to null.  We
do not need a getter.

[jensj, 2017-03-23 07:25:43]

Description was changed from

==========
[kernel] Remove assert, run service tests in debug mode

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

to

==========
[kernel] Fix getter, run service tests in debug mode

Don't create getters for uninitialized static fields.
This fixes two assert hits that was hit when running service tests in debug mode
via kernel. These can thus now be enabled.

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

[jensj, 2017-03-23 07:26:17]

Description was changed from

==========
[kernel] Fix getter, run service tests in debug mode

Don't create getters for uninitialized static fields.
This fixes two assert hits that was hit when running service tests in debug mode
via kernel. These can thus now be enabled.

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

to

==========
[kernel] Fix getter, run service tests in debug mode

Don't create getters for uninitialized static fields.
This fixes two assert hits that was hit when running service tests in debug mode
via kernel. These can thus now be enabled.

BUG=
R=kmillikin@google.com

Committed:
https://github.com/dart-lang/sdk/commit/dc566e137b7e1765f6615410a07e120230eaccf4
==========

[jensj, 2017-03-23 07:26:18]

Committed patchset #2 (id:20001) manually as
dc566e137b7e1765f6615410a07e120230eaccf4 (presubmit successful).