Reland "Recognize and optimize a.runtimeType == b.runtimeType pattern."

Reland "Recognize and optimize a.runtimeType == b.runtimeType pattern."

This relands commit f4ec20abac2286604565e9d5a6d1d744849c964d.

BUG=
R=rmacnak@google.com

Committed: https://github.com/dart-lang/sdk/commit/0635b57d43add7decece07b67b67fb12cfe167aa

[Vyacheslav Egorov (Google), 2016-10-31 18:44:06]

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

[Vyacheslav Egorov (Google), 2016-10-31 18:44:06]

This is an attempt to reland the same CL with the following changes:

- DBC intrinsic now matches all other intrinsics.
- object_store is moved to the place in the Isolate where it's offset does not
change when I precompile for ARM devices on Intel.

Please take a look.

[rmacnak, 2016-10-31 20:23:30]

lgtm

https://codereview.chromium.org/2465793003/diff/1/runtime/vm/isolate.h
File runtime/vm/isolate.h (right):

https://codereview.chromium.org/2465793003/diff/1/runtime/vm/isolate.h#newcod...
runtime/vm/isolate.h:741: // Note: ClassTable has different size between PRODUCT
and non-product builds.
We don't care if product/release/debug have different field offsets. For this
and other reasons, snapshots generated in one of these modes can only run on a
VM of the same mode. The snapshot reader checks they match and issues a specific
error message.

We do care that SIMARM and XARM agree on the field offsets, which I suspect is
what you encountered. Probably from all the bool fields that were above
object_store, which ARM prefers to word align and Intel prefers to pack.

Please add Isolate::object_store_offset() to CheckOffsets in dart.cc

[Vyacheslav Egorov (Google), 2016-11-01 15:49:05]

Description was changed from

==========
Reland "Recognize and optimize a.runtimeType == b.runtimeType pattern."

This relands commit f4ec20abac2286604565e9d5a6d1d744849c964d.

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

to

==========
Reland "Recognize and optimize a.runtimeType == b.runtimeType pattern."

This relands commit f4ec20abac2286604565e9d5a6d1d744849c964d.

BUG=
R=rmacnak@google.com

Committed:
https://github.com/dart-lang/sdk/commit/0635b57d43add7decece07b67b67fb12cfe167aa
==========

[Vyacheslav Egorov (Google), 2016-11-01 15:49:06]

Committed patchset #2 (id:20001) manually as
0635b57d43add7decece07b67b67fb12cfe167aa (presubmit successful).