Commit Graph

32 Commits

Author SHA1 Message Date
Martin Kustermann 92af830255 [vm/concurrency] Move background compiler related state from Isolate to IsolateGroup
As part of making the compiler independent of `Isolate` we have to move
various state from `Isolate` to `IsolateGroup`. This CL moves background
compiler and related state.

One background compiler will be shared for all isolates within a group.

Issue https://github.com/dart-lang/sdk/issues/36097
Fixes https://github.com/dart-lang/sdk/issues/44938

TEST=Mainly refactoring, stress tests for --enable-isolate-groups with JIT will come in the future.

Change-Id: I66e863651d0b37c431ce1864e505b5413850cbde
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/183401
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
2021-02-12 03:40:14 +00:00
Martin Kustermann 75e0837f3e [vm/concurrency] Simplify logic around background compiler, allow concurrent disabling
The logic for background compiler can be simplified due to:

  * we only have one bg compiler
  * it always optimizes
  * it is allocated at isolate startup and freed on isolate shutdown
  * an existing check in the compiler for whether the BG compiler is
    disabled is racy and therefore not helpful
  * when a mutator communicates with BG compiler it will use
    SafepointMutexLocker instead of MutexLocker

This CL also ecapsulates disabling the BG compiler via a
NoBackgroundCompilerScope object. It allows nested disabling and guards
against races.

Issue https://github.com/dart-lang/sdk/issues/36097

TEST=Refactoring of existing code.

Change-Id: I36ed6592c9a8b91e94181698b7de662b4ee984e9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/183400
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
2021-02-10 19:42:55 +00:00
Ryan Macnak b1c09ecd8f [vm] Make naming more consistent when converting between handles, tagged and untagged pointers.
Currently we have things called XPtr which are not what you get from ptr().

Old world:
handle->raw() returns RawObject* (tagged)
raw_obj->ptr() returns RawObject* (untagged)

After 6fe15f6df9:
handle->raw() returns ObjectPtr
obj_ptr->ptr() returns ObjectLayout*

New world:
handle->ptr() returns ObjectPtr
obj_ptr->untag() returns UntaggedObject*

TEST=ci
Change-Id: I6c7f34014cf20737607caaf84979838300d12df2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149367
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2021-01-15 23:32:02 +00:00
Alexander Markov 7588ed86de Remove bytecode mode from the VM
Change-Id: Ief167b7ffc128105a03cc225ab750234c9a6a7a0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/169147
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2020-10-28 17:42:35 +00:00
Ryan Macnak 6fe15f6df9 [vm] Represent tagged pointers as C++ value types instead of C++ pointer types.
This works around bugs in UndefinedBehaviorSanitizer and Clang.

Bug: b/28638298
Change-Id: I6be595f9664516019d28017d24559583a1ae3a21
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/144354
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2020-04-25 05:21:27 +00:00
Vyacheslav Egorov a41a1dc917 [vm/compiler] Split compiler sources out of normal VM sources.
Make them form its own source set (libdart_compiler) and completely exclude
them from AOT runtime targets.

Previously we had some inconsistencies, with some files were using
DART_PRECOMPILED_RUNTIME to fully or partially exclude either contents
from their headers or from implementation, while other files did nothing
and relied on linker to throw their contents away.

This change tries to address this inconsistency.

A follow up change would include a check in most compiler headers which
would prohibit to use them while building AOT runtime.

Change-Id: Ief11b11cbc518b301d3e93fce80580a31bbad151
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/142993
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
2020-04-16 22:59:03 +00:00
Clement Skau 84644e20d6 [SDK] Adds IndirectGoto implementation of sync-yield.
Sets a threshold of five continuations determining if the old
if-else or the new igoto-based implementation will be used.
Informal benchmarking on x64 and arm_x64 point towards the overhead
of the igoto-based impl. dropping off around this point.

Benchmarks of this CL (threshold=5) show drastic improvement in
Calls.IterableManualIterablePolymorphicManyYields of about ~35-65%
across {dart,dart-aot}-{ia32,x64,armv7hf,armv8}.

Note: This is a second revision of a CL landed and reverted from:
https://dart-review.googlesource.com/c/sdk/+/133586
The fix for the previous revert was swapping the parameters to
BuildIndirectEntry(int, int) in kernel_binary_flowgraph.cc.

Bug: https://github.com/dart-lang/sdk/issues/37754
Change-Id: If035235ce8aa660af2ea7f8cfbc8066cde6329b7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/136126
Commit-Queue: Clement Skau <cskau@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
2020-02-18 13:24:09 +00:00
Clement Skau 82f3f81fc8 Revert "[SDK] Adds IndirectGoto implementation of sync-yield."
This reverts commit 7ed1690b4e.

Reason for revert: Crashes precomp.

Original change's description:
> [SDK] Adds IndirectGoto implementation of sync-yield.
> 
> Sets a threshold of five continuations determining if the old
> if-else or the new igoto-based implementation will be used.
> Informal benchmarking on x64 and arm_x64 point towards the overhead
> of the igoto-based impl. dropping off around this point.
> 
> Benchmarks of this CL (threshold=5) show drastic improvement in
> Calls.IterableManualIterablePolymorphicManyYields of about ~35-65%
> across {dart,dart-aot}-{ia32,x64,armv7hf,armv8}.
> 
> Bug: https://github.com/dart-lang/sdk/issues/37754
> Change-Id: I6e113f1f98e9ab0f994cf93004227d616e9e4d07
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/133586
> Commit-Queue: Clement Skau <cskau@google.com>
> Reviewed-by: Martin Kustermann <kustermann@google.com>

TBR=kustermann@google.com,cskau@google.com

Change-Id: Ie212fae88bc1977e34e4d791c644b77783a8deb1
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: https://github.com/dart-lang/sdk/issues/37754
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/136125
Reviewed-by: Clement Skau <cskau@google.com>
Commit-Queue: Clement Skau <cskau@google.com>
2020-02-17 12:17:25 +00:00
Clement Skau 7ed1690b4e [SDK] Adds IndirectGoto implementation of sync-yield.
Sets a threshold of five continuations determining if the old
if-else or the new igoto-based implementation will be used.
Informal benchmarking on x64 and arm_x64 point towards the overhead
of the igoto-based impl. dropping off around this point.

Benchmarks of this CL (threshold=5) show drastic improvement in
Calls.IterableManualIterablePolymorphicManyYields of about ~35-65%
across {dart,dart-aot}-{ia32,x64,armv7hf,armv8}.

Bug: https://github.com/dart-lang/sdk/issues/37754
Change-Id: I6e113f1f98e9ab0f994cf93004227d616e9e4d07
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/133586
Commit-Queue: Clement Skau <cskau@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
2020-02-17 09:59:25 +00:00
Martin Kustermann aceeba7567 [vm/async] Encode the yield index -> token position in PcDescriptors.
Right now `Script::yield_positions()` is an array mapping function start
token positions to arrays. Those arrays contain token positions and are
indexed by yield index.
  => This `Script::yield_positions()` is not available in AOT mode.

The fast async stack implementation will need to be able to find out
where an async closure was suspended. It does so by looking at the
":await_jump_var", which contains the yield index. It then needs to
associate the yield index to token position of the yield.

This CL adds an entry into the PcDescriptors for every yield in a
async/async* function and removes `Script::yield_positions()`.
The entry will associate the yield index with the token position.

Flutter gallery total size impact for flutter-release:

  - armv7: +0.016%
  - armv8: +0.045%

Issue https://github.com/dart-lang/sdk/issues/37668

Change-Id: I0b2ce41e85d8f5d590201bf2fb091578d7379890
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/125408
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Clement Skau <cskau@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
2019-11-18 11:50:13 +00:00
Zichang Guo 59bcc4ea1e [vm/kernel] record yield positions at streaming flow graph builder
Collect yield positions inside StreamFlowGraphBuilder. BuildGraph() when yield_positions() are required. All yield positions will be stored into script as a hashmap. Key of hashmap is the starting token position of function, value is an array containing all yield positions.

Bug: https://github.com/dart-lang/sdk/issues/37635
Change-Id: I6d301d1cb0f74c432f855c9dbc20ac2c13acb07f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/116743
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
Commit-Queue: Zichang Guo <zichangguo@google.com>
2019-09-12 16:37:16 +00:00
Alexander Markov 1eb1520702 [vm/bytecode] Prevent triggering optimizing compilation from interpreter
Previously, in rare cases it was possible that interpreter would trigger
optimizing compilation (if function usage counter reached threshold
in the interpreter once again after unoptimized compilation finished).

This results in producing optimized code without any feedback (as
unoptimized code hasn't executed).

Change-Id: Ibd52b7dfe3a808ade97c02e743b40aa466b1e3c2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/108687
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
2019-07-11 17:45:49 +00:00
Ryan Macnak 2be92b08c2 [vm] Remove more of the Dart 1 compiler.
Change-Id: Ib00e040f44275b9437e7fc622bf285607f4e4124
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/105681
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2019-06-12 01:00:29 +00:00
Matthew Dempsky 6d5f763952 [vm] Eliminate Mutex/Monitor indirection where possible
In many cases, the Mutexes and Monitors have to be marked "mutable"
because they're used to synchronize const accessor methods.

Small text segment improvement for Product builds:

$ size dart.{arm,x64}.{before,after}
   text	   data	    bss	    dec	    hex	filename
19726069	 409960	 392332	20528361	1393ce9	dart.arm.before
19725525	 409960	 392332	20527817	1393ac9	dart.arm.after
22576021	 600376	1782824	24959221	17cd8f5	dart.x64.before
22574821	 600376	1782824	24958021	17cd445	dart.x64.after

Change-Id: I68f5cd5ad452044df8bfebd160910496036a3e6b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/101745
Commit-Queue: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2019-05-13 21:17:51 +00:00
asiva dc9370a07d [vm/runtime] Create separate background compilation queues for optimized and unoptimized compilations.
- create separate compilation queues for optimized and compilation
queues
- remove option FLAG_background_compilation_stop_alot doesn't seem to be used in any format testing
- remove some class finalization checks before starting the background compiler

Change-Id: I98f1773987e33a43e7b43ace4c383d17bd0a1710
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98453
Reviewed-by: Zach Anderson <zra@google.com>
2019-04-03 00:58:43 +00:00
Siva Annamalai 057497e57b Revert "[vm/runtime] Create separate background compilation queues for optimized and unoptimized compilations."
This reverts commit bcb6df13b9.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> [vm/runtime] Create separate background compilation queues for optimized and unoptimized compilations.
> 
> - create separate compilation queues for optimized and compilation
> queues
> - remove option FLAG_background_compilation_stop_alot doesn't seem to be used in any format testing
> - remove some class finalization checks before starting the background compiler
> 
> Change-Id: I09feb500c2a5cc9c6e93347f63bfca41b83b35cf
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98301
> Reviewed-by: Zach Anderson <zra@google.com>
> Commit-Queue: Siva Annamalai <asiva@google.com>

TBR=zra@google.com,asiva@google.com

Change-Id: I3faf74c95dce7741c75f8836cce30f9dba2e154c
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98448
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Siva Annamalai <asiva@google.com>
2019-04-02 01:17:24 +00:00
asiva bcb6df13b9 [vm/runtime] Create separate background compilation queues for optimized and unoptimized compilations.
- create separate compilation queues for optimized and compilation
queues
- remove option FLAG_background_compilation_stop_alot doesn't seem to be used in any format testing
- remove some class finalization checks before starting the background compiler

Change-Id: I09feb500c2a5cc9c6e93347f63bfca41b83b35cf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/98301
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Siva Annamalai <asiva@google.com>
2019-04-02 00:32:33 +00:00
Ryan Macnak cf32584870 [vm] Support compiling static field initializers and dynamic invocation forwarders from a compilation trace.
Clean up creating static field initializers.

Change-Id: I914263f532be1d1a7216d3b5e35d05c4f0fdf167
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/97547
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
2019-03-28 00:48:30 +00:00
asiva 2427a69e14 [VM/Runtime] Refactoring sources to enable interpreter only builds.
The interpreter only build of the Dart VM should not be including any
sources from the 'compiler' directory.
First part of restructuring sources to enable an interpreter only build
of the VM
- Move CompileClass from compiler.cc file to class_finalizer.cc

Change-Id: I8743c6537ed2d63e6991d78949f858a1ae506121
Reviewed-on: https://dart-review.googlesource.com/c/87987
Commit-Queue: Siva Annamalai <asiva@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
2019-01-07 18:49:17 +00:00
Alexander Markov 4b900fdcc5 [vm] Clarify timeline events for unoptimized background compilation, take 2
Change-Id: Iaeb9fb612e2060a59ba3963402e15ae97e27cb5f
Reviewed-on: https://dart-review.googlesource.com/c/84042
Auto-Submit: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
2018-11-09 18:36:17 +00:00
Alexander Markov f9d93f6d4e Revert "[vm] Clarify timeline events for unoptimized background compilation"
This reverts commit 136c013bea.

Reason for revert: broken dartkb bots

Original change's description:
> [vm] Clarify timeline events for unoptimized background compilation
> 
> Change-Id: I919ef5a5a180b47eba31e74d32da4185fff81df9
> Reviewed-on: https://dart-review.googlesource.com/c/83886
> Commit-Queue: Alexander Markov <alexmarkov@google.com>
> Auto-Submit: Alexander Markov <alexmarkov@google.com>
> Reviewed-by: Ryan Macnak <rmacnak@google.com>

TBR=rmacnak@google.com,alexmarkov@google.com,zra@google.com,asiva@google.com

Change-Id: Ifcdd8778f60c25e7b1363538e0f76064dde09556
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/83921
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
2018-11-09 03:08:07 +00:00
Alexander Markov 136c013bea [vm] Clarify timeline events for unoptimized background compilation
Change-Id: I919ef5a5a180b47eba31e74d32da4185fff81df9
Reviewed-on: https://dart-review.googlesource.com/c/83886
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Auto-Submit: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2018-11-09 01:38:02 +00:00
Ryan Macnak 235a918233 [vm] Remove Dart_LoadScript, Dart_LoadLibrary, Dart_LoadSource, etc.
Change-Id: I9c19625702f1df48c03de2eb3a0f7bb581d2e0b3
Reviewed-on: https://dart-review.googlesource.com/c/79140
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
2018-10-11 00:38:37 +00:00
asiva c9f5c3a79e [VM] Delete access to Dart 1 parser.
- delete access to Dart 1 parser
- Skip codegen unit tests as they use the Dart 1 parser

Change-Id: I24f3986fac9c496e231c723c6eaa0704e6a616f5
Reviewed-on: https://dart-review.googlesource.com/77009
Commit-Queue: Siva Annamalai <asiva@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
2018-09-27 23:08:20 +00:00
Zach Anderson dba8b37d38 [vm] Benchmark for reading kernel bytecode
Change-Id: I07617a553193495fcc4fc0ce4a6382996ee7dc51
Reviewed-on: https://dart-review.googlesource.com/75821
Commit-Queue: Zach Anderson <zra@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
2018-09-24 15:54:49 +00:00
Alexander Markov 46ec629096 [vm/bytecode] Trigger JIT-compilation from interpreter
Performance on Richards benchmark (no bytecode in platform, release build):

Interpreter (--enable-interpreter --compilation-counter-threshold=-1)
Richards(RunTime): 177228.34433333334 us.

Interpreter + bytecode compilation with default threshold 10 (--enable-interpreter)
Richards(RunTime): 930.8050725919032 us.
Varies from run to run, spikes up to 4178.005912317328 (no OSR yet, only background compilation).

Bytecode compilation (--use-bytecode-compiler)
Richards(RunTime): 830.1371626556016 us

Default pipeline:
Richards(RunTime): 880.1557113946327 us.

Numbers on Richards benchmark (platform with bytecode, release build):

Interpreter (--enable-interpreter --compilation-counter-threshold=-1)
Richards(RunTime): 354553.6346666667 us.

Interpreter + compilation with default threshold 10 (--enable-interpreter)
Richards(RunTime): 934.7108855140189 us.

Bytecode compilation (--use-bytecode-compiler)
Richards(RunTime): 822.74178403949 us.


Change-Id: Ic13e9f7c7d98f2930e6de4c4f74bac4d28478249
Reviewed-on: https://dart-review.googlesource.com/75781
Reviewed-by: Zach Anderson <zra@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
2018-09-20 20:57:08 +00:00
Alexander Markov c6c4748185 [vm/bytecode] Bytecode compilation
Change-Id: I09192e4e929a397920c217b605580f8c4880e7c2
Reviewed-on: https://dart-review.googlesource.com/74002
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Régis Crelier <regis@google.com>
2018-09-14 22:02:29 +00:00
Régis Crelier a2fae0125f [VM interpreter] Mark activation frames as interpreted instead of crashing.
This is a first step in supporting bytecode in the debugger.

Change-Id: Ieb06b8b534fcc7f0291457cd6912d772b8ee247a
Reviewed-on: https://dart-review.googlesource.com/74012
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Régis Crelier <regis@google.com>
2018-09-12 00:33:30 +00:00
Vyacheslav Egorov 7558644bd6 [vm/compiler] Move compiler state (CHA, deopt id) from Thread to a special class
Also move deopt id computation logic into a separate class and add a comment
explaining while deopt ids are incremented by 2.

Change-Id: Ife489be7d10c7198a8e7adf9e97e0c516d78ea55
Reviewed-on: https://dart-review.googlesource.com/72685
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
2018-09-03 16:01:24 +00:00
Ryan Macnak 9174a627f5 [vm, gc] Ensure BackgroundCompiler can't be deleted during a safepoint.
Previously, the background compiler was deleted by the thread pool, which could have raced ahead of the mutator clearing its reference. Now it is deleted by the mutator.

Change-Id: Id353a96022f699131ee60fe31156cd0404dfd285
Reviewed-on: https://dart-review.googlesource.com/24342
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
2017-11-30 22:59:51 +00:00
Jens Johansen 54f44f2a18 [kernel] Assert not optimizing when running constant evaluator.
Previously we could hit an assert when for instance "42 ~/ 0"
was being optimized by the background compiler. The reason was
that we assert that we're on the "mutator thread" when allocating
memory (which is done as we're evaluating the code - and we're
trying to evaluate it again because evaluating it gives an error,
and errors aren't cached).

However, to create a test for this it would be better if we could
make it always crash, i.e. use something like
```
--optimization_counter_threshold=5 --no-background-compilation
```
to force an optimization, but still make it crash dispite the
optimization happening in mutator thread (because of
--no-background-compilation).

This CL propagates if we're optimizing to the kernel builder,
and in the constant builder further more asserts that we're not.

Additionally it introduces a test that shows the crash and fixes it.

Change-Id: Ic5412ec8b8a1dbc2ba323f0a02a51103a32fab5c
Reviewed-on: https://dart-review.googlesource.com/11380
Commit-Queue: Jens Johansen <jensj@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2017-10-05 11:48:10 +00:00
Vyacheslav Egorov 8a179fb953 [VM, Compiler] Move compiler to a separate folder.
New folder structure (nested under vm/):

- compiler/
-   jit/         - JIT specific code
-   aot/         - AOT specific code
-   backend/     - all middle-end and back-end code (IL, flow graph)
-   assembler/   - assemblers and disassemblers
-   frontend/    - front ends (AST -> IL, Kernel -> IL)

compiler/README.md would be the documentation root for the compiler
pipeline

Bug: https://github.com/dart-lang/sdk/issues/30575
Change-Id: I2dfd9688793bff737f7632ddc77fca766875ce36
Reviewed-on: https://dart-review.googlesource.com/2940
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
2017-09-04 15:15:18 +00:00