Collects files from `package:async_helper` and `tests/language`
that are generally useful, so that all test-related helpers are
in `package:expect`.
Moves the two libraries from `package:async_helper` into `package:expect`,
and the `tests/language/static_type_helper.dart` file too.
Deprecates `async_minitest.dart`, to follow `minitest.dart`,
expecting the Flutter use of it to have been fixed to not break
on deprecation (I believe Flutter no longer breaks builds on deprecations at all).
Patch 1 is the actual change.
Patch 2+4+8 is changing all existing references to the files.
Patch 6 ignores deprecation in files still using `async_minitest.dart`.
3+5+7+9 are updating this text to make the numbers match.
Then it's just test-expectations and small tweaks from there.
Change-Id: I1b665135b5fef9b9a0c3b340ffe9daf874d0174c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/373120
Reviewed-by: Nate Bosch <nbosch@google.com>
Reviewed-by: Devon Carew <devoncarew@google.com>
Commit-Queue: Lasse Nielsen <lrn@google.com>
This reverts commit cd2c566bcf.
Reason for revert: Updating to not remove field used by Flutter engine.
Original change's description:
> Revert "Tweak `expect.dart` library."
>
> This reverts commit ff5f391c0a.
>
> Reason for revert: The expect library is used by Flutter engine, and some of its tests use assertStatementsEnabled. There should be a migration path that doesn't require an atomic change, like adding the replacement api before removing the old one.
>
> Original change's description:
> > Tweak `expect.dart` library.
> >
> > Make API more consistent for a few methods.
> > Reduce the number of language features used in tests:
> > * Never iterating an iterable, always converting it
> > using `.toList()` first and iterating using indices
> > (fx `setEquals`).
> > Also require a `List` in places where an `Iterable`
> > wasn't necessary.
> > * Avoid doing complicated computations that are also
> > used for the error message. Do simple check first,
> > then recompute to get better error messages
> > (fx `allDistinct`).
> >
> > Renamed some rarely used members for consistency
> > (`stringContainsInOrder`->`containsInOrder`,
> > where other string-contains functions just start
> > with `contains`, and `containsOneOf` -> `containsAny`
> > to match `Iterable.any` phrasing, and also it accepts
> > if containing at least one, not precisely one.)
> >
> > Removed a function that wasn't used anywhere.
> >
> > Moved `assertStatementsEnabled` to `variations.dart` as `asserts`.
> > Removed `typeAssertionsEnabled` and `checkedModeEnabled`. The former used in one place, where it was replaced with `checkedImplicitDowncasts` from `variations.dart`, the latter wasn't used anywhere.
> >
> > Deprecates `package:expect/minitest.dart`. It was never intended
> > to be used for new tests, only as a help to convert existing tests
> > written against `package:unit_test`.
> > All existing imports marked as `// ignore: deprecated_member_use`.
> >
> > Change-Id: I07e21d4c0f3ccf11b82ee34af2668fdbb22264d2
> > Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/352360
> > Reviewed-by: Slava Egorov <vegorov@google.com>
> > Reviewed-by: Ömer Ağacan <omersa@google.com>
> > Reviewed-by: Nate Bosch <nbosch@google.com>
> > Reviewed-by: Stephen Adams <sra@google.com>
> > Commit-Queue: Lasse Nielsen <lrn@google.com>
>
> Change-Id: I360b4347470a0bb2b63c3108e2b83ee2a771bf3f
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/362020
> Reviewed-by: Nate Bosch <nbosch@google.com>
> Reviewed-by: Ömer Ağacan <omersa@google.com>
> Reviewed-by: Stephen Adams <sra@google.com>
> Reviewed-by: Leaf Petersen <leafp@google.com>
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Commit-Queue: William Hesse <whesse@google.com>
CoreLibraryReviewExempt: Reland
Change-Id: I53db40edc0733842a008839c3913d51c885e39ab
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/362502
Reviewed-by: Alexander Thomas <athom@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Reviewed-by: Ömer Ağacan <omersa@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Reviewed-by: William Hesse <whesse@google.com>
Commit-Queue: Lasse Nielsen <lrn@google.com>
This reverts commit ff5f391c0a.
Reason for revert: The expect library is used by Flutter engine, and some of its tests use assertStatementsEnabled. There should be a migration path that doesn't require an atomic change, like adding the replacement api before removing the old one.
Original change's description:
> Tweak `expect.dart` library.
>
> Make API more consistent for a few methods.
> Reduce the number of language features used in tests:
> * Never iterating an iterable, always converting it
> using `.toList()` first and iterating using indices
> (fx `setEquals`).
> Also require a `List` in places where an `Iterable`
> wasn't necessary.
> * Avoid doing complicated computations that are also
> used for the error message. Do simple check first,
> then recompute to get better error messages
> (fx `allDistinct`).
>
> Renamed some rarely used members for consistency
> (`stringContainsInOrder`->`containsInOrder`,
> where other string-contains functions just start
> with `contains`, and `containsOneOf` -> `containsAny`
> to match `Iterable.any` phrasing, and also it accepts
> if containing at least one, not precisely one.)
>
> Removed a function that wasn't used anywhere.
>
> Moved `assertStatementsEnabled` to `variations.dart` as `asserts`.
> Removed `typeAssertionsEnabled` and `checkedModeEnabled`. The former used in one place, where it was replaced with `checkedImplicitDowncasts` from `variations.dart`, the latter wasn't used anywhere.
>
> Deprecates `package:expect/minitest.dart`. It was never intended
> to be used for new tests, only as a help to convert existing tests
> written against `package:unit_test`.
> All existing imports marked as `// ignore: deprecated_member_use`.
>
> Change-Id: I07e21d4c0f3ccf11b82ee34af2668fdbb22264d2
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/352360
> Reviewed-by: Slava Egorov <vegorov@google.com>
> Reviewed-by: Ömer Ağacan <omersa@google.com>
> Reviewed-by: Nate Bosch <nbosch@google.com>
> Reviewed-by: Stephen Adams <sra@google.com>
> Commit-Queue: Lasse Nielsen <lrn@google.com>
Change-Id: I360b4347470a0bb2b63c3108e2b83ee2a771bf3f
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/362020
Reviewed-by: Nate Bosch <nbosch@google.com>
Reviewed-by: Ömer Ağacan <omersa@google.com>
Reviewed-by: Stephen Adams <sra@google.com>
Reviewed-by: Leaf Petersen <leafp@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: William Hesse <whesse@google.com>
Make API more consistent for a few methods.
Reduce the number of language features used in tests:
* Never iterating an iterable, always converting it
using `.toList()` first and iterating using indices
(fx `setEquals`).
Also require a `List` in places where an `Iterable`
wasn't necessary.
* Avoid doing complicated computations that are also
used for the error message. Do simple check first,
then recompute to get better error messages
(fx `allDistinct`).
Renamed some rarely used members for consistency
(`stringContainsInOrder`->`containsInOrder`,
where other string-contains functions just start
with `contains`, and `containsOneOf` -> `containsAny`
to match `Iterable.any` phrasing, and also it accepts
if containing at least one, not precisely one.)
Removed a function that wasn't used anywhere.
Moved `assertStatementsEnabled` to `variations.dart` as `asserts`.
Removed `typeAssertionsEnabled` and `checkedModeEnabled`. The former used in one place, where it was replaced with `checkedImplicitDowncasts` from `variations.dart`, the latter wasn't used anywhere.
Deprecates `package:expect/minitest.dart`. It was never intended
to be used for new tests, only as a help to convert existing tests
written against `package:unit_test`.
All existing imports marked as `// ignore: deprecated_member_use`.
Change-Id: I07e21d4c0f3ccf11b82ee34af2668fdbb22264d2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/352360
Reviewed-by: Slava Egorov <vegorov@google.com>
Reviewed-by: Ömer Ağacan <omersa@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Reviewed-by: Stephen Adams <sra@google.com>
Commit-Queue: Lasse Nielsen <lrn@google.com>
This CL introduces a way to mark all instances of a class as deeply
immutable.
In order to statically verify that all instances of a deeply immutable
class are immutable, a deeply immutable classes must have the following
properties:
1. All instance fields must
1. have a deeply immutable type,
2. be final, and
3. be non-late.
2. The class must be `final` or `sealed`. This ensures no
non-deeply-immutable subtypes are added by external code.
3. All subtypes must be deeply immutable. This ensures 1.1 can be
trusted.
4. The super type must be deeply immutable (except for Object).
Note that instances of some classes in the VM are deeply immutable
while their class cannot be marked immutable.
* SendPort, Capability, RegExp, and StackTrace are not `final` and
can be implemented by external code.
* UnmodifiableTypedDataViews do not have a public type. (It was
recently deprecated.)
See runtime/docs/deeply_immutable.md for more details.
Use case:
This enables attaching a `Dart_FinalizableHandle` to a deeply immutable
object and the deeply immutable object with other isolates in the same
isolate group.
(Note that `NativeFinalizer`s live in an isolate, and not an isolate
group. So this should currently _not_ be used with `NativeFinalizer`s.
See https://github.com/dart-lang/sdk/issues/55062 for making a
`NativeFinalizer.shared(` that would live in an isolate group instead
of in an isolate.)
Implementation details:
Before this CL, the `ImmutableBit` in the object header was only ever
set to true for predefined class ids (and for const objects). After
this CL, the bit can also be set to true for non const instances of
user-defined classes. The object allocation and initialization code has
been changed to deal with this new case. The immutability of a class is
saved in the class state bits. On object allocation and initialization
the immutability bit is read from the class for non-predefined class
ids.
TEST=runtime/tests/vm/dart/isolates/fast_object_copy2_test.dart
TEST=runtime/vm/isolate_reload_test.cc
TEST=tests/lib/isolate/deeply_immutable_*
Bug: https://github.com/dart-lang/sdk/issues/55120
Bug: https://github.com/dart-lang/sdk/issues/54885
Change-Id: Ib97fe589cb4f81673cb928c93e3093838d82132d
Cq-Include-Trybots: luci.dart.try:vm-aot-android-release-arm64c-try,vm-aot-android-release-arm_x64-try,vm-aot-linux-debug-x64-try,vm-aot-linux-debug-x64c-try,vm-aot-mac-release-arm64-try,vm-aot-mac-release-x64-try,vm-aot-obfuscate-linux-release-x64-try,vm-aot-optimization-level-linux-release-x64-try,vm-appjit-linux-debug-x64-try,vm-asan-linux-release-x64-try,vm-checked-mac-release-arm64-try,vm-eager-optimization-linux-release-ia32-try,vm-eager-optimization-linux-release-x64-try,vm-ffi-android-debug-arm-try,vm-ffi-android-debug-arm64c-try,vm-ffi-qemu-linux-release-arm-try,vm-ffi-qemu-linux-release-riscv64-try,vm-fuchsia-release-x64-try,vm-kernel-linux-debug-x64-try,vm-kernel-precomp-linux-release-x64-try,vm-linux-debug-ia32-try,vm-linux-debug-x64-try,vm-linux-debug-x64c-try,vm-mac-debug-arm64-try,vm-mac-debug-x64-try,vm-msan-linux-release-x64-try,vm-reload-linux-debug-x64-try,vm-reload-rollback-linux-debug-x64-try,vm-ubsan-linux-release-x64-try
Cq-Include-Trybots: dart-internal/g3.dart-internal.try:g3-cbuild-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/354902
Commit-Queue: Daco Harkes <dacoharkes@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Decorate Zone, Future, Completer, Timer and Stream with newly-introduced pragma to make sure that message verification stops earlier, produces shorter retaining path for the user.
BUG=https://github.com/dart-lang/sdk/issues/51722
TEST=send_unsupported_objects_test,isolate_exit_unsendable_test.dart
CoreLibraryReviewExempt: vm-specific pragmas
Change-Id: I499eea542d228ac9cf0797a682664f93f360dc80
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/289027
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Mark tests that contain errors about using a class as a mixin to use
language version 2.19 where that's not an error.
This may not fix all of the tests because it's the language version of
the library where the class is declared that matters, not where the
class is used as a mixin. But most tests have all of their declarations
in the same library, so this should fix most.
Change-Id: I910439ebd2f10f731418dc588b7e4619a0841c16
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/285923
Reviewed-by: Jake Macdonald <jakemac@google.com>
Commit-Queue: Jake Macdonald <jakemac@google.com>
- Flip flag to make strong null safety the default
- Remove code that auto detects null safety mode from source files,
it is necessary to specify --no-strong-null-safety to opt out.
- Retains sniffing of AOT/JIT snapshots and kernel files to determine
null safety mode, the opt out has to be done when generating these
file.
TEST=ci
Change-Id: If2c9608eedb7c46d9c3cd85e261ee9640e0d28eb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/261140
Reviewed-by: Alexander Thomas <athom@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Siva Annamalai <asiva@google.com>
Reviewed-by: Sigmund Cherem <sigmund@google.com>
The current VM closure serialization makes this function a foot-gun.
Revert until the supporting features are improved, so as to not give
users a bad experience.
Change-Id: I83b6b453ce5ab00d49ffbf36a5763119a6435352
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/237940
Reviewed-by: Michael Thomsen <mit@google.com>
Commit-Queue: Lasse Nielsen <lrn@google.com>
Right now the implementation of `Isolate.spawnUri(<uri>, ...)` in
the standalone embedder is to ignore `<uri>` and make the spawnned
isolate from the same AOT snapshot as the main isolate.
This is very confusing and very incorrect.
Instead `Isolate.spawnUri()` should work if-and-only-if the given
`<uri>` points to a valid and compatible AOT snapshot. If not, it should
throw an appropriate exception.
Fixes https://github.com/dart-lang/sdk/issues/48375
Fixes https://github.com/dart-lang/sdk/issues/48326
TEST=vm/dart{,_2}/spawn_uri_aot_test
Change-Id: I279ace08ac1b9a9eed3ae03ebe5d9e2336c1e5c9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/232603
Reviewed-by: Tess Strickland <sstrickl@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
This CL implements `WeakReference` in the VM.
* This reduces the size of weak references from 2 objects using 8 words
to 1 object using 4 words.
* This makes loads of weak reference targets a single load instead of
two.
* This avoids the fix-point in the GC and message object copying for
weak references. (N.b. Weak references need to be processed _after_
the fix-point for weak properties.)
The semantics of weak references in messages is that their target gets
set to `null` if the target is not included in the message by a strong
reference.
The tests take particular care to exercise the case where a weak
reference's target is only kept alive because a weak property key is
alive and it refers to the target in its value. This exercises the fact
that weak references need to be processed last.
Does not add support for weak references in the app snapshot. It would
be dead code until we start using weak references in for example the
CFE.
This CL does not try to unify weak references and weak properties in
the GC or messaging (as proposed in go/dart-vm-weakreference), because
their semantics differ enough.
Closes: https://github.com/dart-lang/sdk/issues/48162
TEST=runtime/tests/vm/dart/finalizer/weak_reference_run_gc_test.dart
TEST=runtime/tests/vm/dart/isolates/fast_object_copy_test.dart
TEST=runtime/vm/object_test.cc
TEST=tests/lib/isolate/weak_reference_message_1_test.dart
TEST=tests/lib/isolate/weak_reference_message_2_test.dart
Change-Id: I3810e919a5866f3ae8a95bd9aa23a880a0b0921c
Cq-Include-Trybots: luci.dart.try:app-kernel-linux-debug-x64-try,dart-sdk-mac-arm64-try,vm-canary-linux-debug-try,vm-fuchsia-release-x64-try,vm-kernel-gcc-linux-try,vm-kernel-asan-linux-release-x64-try,vm-kernel-linux-debug-x64c-try,vm-kernel-linux-debug-x64-try,vm-kernel-linux-debug-simriscv64-try,vm-kernel-mac-debug-x64-try,vm-kernel-nnbd-linux-debug-x64-try,vm-kernel-nnbd-linux-release-ia32-try,vm-kernel-nnbd-linux-release-simarm64-try,vm-kernel-nnbd-linux-release-simarm-try,vm-kernel-nnbd-mac-debug-arm64-try,vm-kernel-nnbd-mac-debug-x64-try,vm-kernel-nnbd-win-release-ia32-try,vm-kernel-nnbd-win-release-x64-try,vm-kernel-optcounter-threshold-linux-release-x64-try,vm-kernel-precomp-android-release-arm_x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-debug-x64c-try,vm-kernel-precomp-win-debug-x64c-try,vm-kernel-reload-rollback-linux-debug-x64-try,vm-kernel-reload-linux-debug-x64-try,vm-kernel-win-debug-ia32-try,vm-kernel-win-debug-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/232087
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Daco Harkes <dacoharkes@google.com>
This is a preparation CL to remove the --enable-isolate-groups flag in
the VM.
The following tests were only running in --no-enable-isolate-groups and
are therefore obsolete now:
- runtime/tests/vm/dart/regress_47468_test.dart
- runtime/tests/vm/dart_2/regress_47468_test.dart
- tests/lib/isolate/illegal_msg_function_test.dart
- tests/lib_2/isolate/illegal_msg_function_test.dart
TEST=Changes tests only.
Change-Id: I6257cb667eebca66a649614d3010139dd2cdd3ab
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/219100
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
The existing lib/isolate/stacktrace_message_test was failing and also
incorrectly written due to "!" in front of the expected stringification
of the stacktrace.
Issue https://github.com/dart-lang/sdk/issues/46623
TEST=vm/dart{,_2}/isolates/fast_object_copy2_test, lib{,_2}/isolate/stacktrace_message_test
Change-Id: I169d8fd7a7c3cb3b8c57e00287565e3a5c622acf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/216041
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
Add missing checks for FFI types disallowed in isolate messages.
Align error messages with the other serializer and test expectations.
TEST=ci
Change-Id: I3813dd8f26e5122524bdf41f9ce6e0785fdd260b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/209840
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
The transitive copy algorithm was missing support for [WeakProperty]s,
thereby ensuring that we only copy the values if the keys are reachable.
Furthermore we might need to re-hash [Expando]s - since the copied
objects start with no identity hash codes.
The CL also makes us avoid calling to Dart for each [Expando]
separately and instead use a list - just as we do in the re-hashing of
maps/sets.
We also move the C++ code to invoke rehashing logic into
DartLibraryCalls::*.
Issue https://github.com/dart-lang/sdk/issues/36097
TEST=vm/dart{,_2}/isolates/fast_object_copy{,2}_test
Change-Id: I836745feef8a6d7573faa94e29a19c1eca0c39f2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/209106
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
This CL
* Removes conditional Skip markers in status files
* Removes some outdated TODOs in the code
* Deletes tests/lib_2/isolate/isolate_stress_test
=> It's skipped everywhere, we no longer support isolates on web
* Fixes standalone{,_2}/io/directory_list_sync_test:
=> Instead of relying on the Platform.script which could be an ELF
file lying somewhere else, use Platform.executable instead
* Fixes standalone{,_2}/io/unix_socket_test:
=> The server used `sub.cancel()` to close it's reading end while
the client tried to write to it. This is racy.
If the server goes first, the write on client will throw (since
no error listener was installed on socket.done)
Avoid the race by coordinating client/server.
Issue https://github.com/dart-lang/sdk/issues/36097
TEST=Enables more tests.
Change-Id: I0464f81f540f2eda23ef4199cc536e53e6a809b9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/207120
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
We use message passing as comunication mechanism between isolates.
The transitive closure of an object to be sent is currently serialized
into a snapshot form and deserialized on the receiver side. Furthermore
the receiver side will re-hash any linked hashmaps in that graph.
If isolate gropus are enabled we have all isolates in a group work on
the same heap. That removes the need to use an intermediate
serialization format. It also removes the need for an O(n) step on the
receiver side.
This CL implements a fast transitive object copy implementation and
makes use of it a message that is to be passed to another isolate stays
within the same isolate group.
In the common case the object graph will fit into new space. So the
copy algorithm will try to take advantage of it by having a fast path
and a fallback path. Both of them effectively copy the graph in BFS
order.
The algorithm works effectively like a scavenge operation, but instead
of first copying the from-object to the to-space and then re-writing the
object in to-space to forward the pointers (which requires us writing to
the to-space memory twice), we only reserve space for to-objects and
then initialize the to-objects to it's final contents, including
forwarded pointers (i.e. write the to-space object only once).
Compared with a scavenge operation (which stores forwarding pointers in
the objects themselves), we use a [WeakTable] to store them. This is the
only remaining expensive part of the algorithm and could be further
optimized. To avoid relying on iterating the to-space, we'll remember
[from, to] addresses.
=> All of this works inside a [NoSafepointOperationScope] and avoids
usages of handles as well as write barriers.
While doing the transitive object copy, we'll share any object we can
safely share (canonical objects, strings, sendports, ...) instead of
copying it.
If the fast path fails (due to allocation failure or hitting) we'll
handlify any raw pointers and continue almost the same algorithm in a
safe way, where GC is possible at every object allocation site and
normal barriers are used for any stores of object pointers.
The copy algorithm uses templates to share the copy logic between the
fast and slow case (same copy routines can work on raw pointers as well
as handles).
There's a few special things to take into consideration:
* If we copy a view on external typed data we need to know the
external typed data address to compute the inner pointer of the
view, so we'll eagerly initialize external typed data.
* All external typed data needs to get a finalizer attached
(irrespective if the object copy suceeds or not) to ensure the
`malloc()`ed data is freed again.
* Transferables will only be transferred on successful transitive
copies. Also they need to attach finalizers to objects (which
requires all objects be in handles).
* We copy linked hashmaps as they are - instead of compressing the
data by removing deleted entries. We may need to re-hash those
hashmaps on the receiver side (similar to the snapshot-based copy
approach) since new object graph will have no identity hash codes
assigned to them. Though if the hashmaps only has sharable objects
as keys (very common, e.g. json) there is no need for re-hashing.
It changes the SendPort.* benchmarks as follows:
```
Benchmark | default | IG | IG + FOC
----------------------------------------------------------------------------------------------------------------------------
SendPort.Send.Nop(RunTimeRaw): | 0.25 us (1 x) | 0.26 us (0.96 x) | 0.25 us (1.00 x)
SendPort.Send.Json.400B(RunTimeRaw): | 4.15 us (1 x) | 1.45 us (2.86 x) | 1.05 us (3.95 x)
SendPort.Send.Json.5KB(RunTimeRaw): | 82.16 us (1 x) | 27.17 us (3.02 x) | 18.32 us (4.48 x)
SendPort.Send.Json.50KB(RunTimeRaw): | 784.70 us (1 x) | 242.10 us (3.24 x) | 165.50 us (4.74 x)
SendPort.Send.Json.500KB(RunTimeRaw): | 8510.4 us (1 x) | 3083.80 us (2.76 x) | 2311.29 us (3.68 x)
SendPort.Send.Json.5MB(RunTimeRaw): | 122381.33 us (1 x) | 62959.40 us (1.94 x) | 55492.10 us (2.21 x)
SendPort.Send.BinaryTree.2(RunTimeRaw): | 1.91 us (1 x) | 0.92 us (2.08 x) | 0.72 us (2.65 x)
SendPort.Send.BinaryTree.4(RunTimeRaw): | 6.32 us (1 x) | 2.70 us (2.34 x) | 2.10 us (3.01 x)
SendPort.Send.BinaryTree.6(RunTimeRaw): | 25.24 us (1 x) | 10.47 us (2.41 x) | 8.61 us (2.93 x)
SendPort.Send.BinaryTree.8(RunTimeRaw): | 104.08 us (1 x) | 41.08 us (2.53 x) | 33.51 us (3.11 x)
SendPort.Send.BinaryTree.10(RunTimeRaw): | 373.39 us (1 x) | 174.11 us (2.14 x) | 134.75 us (2.77 x)
SendPort.Send.BinaryTree.12(RunTimeRaw): | 1588.64 us (1 x) | 893.18 us (1.78 x) | 532.05 us (2.99 x)
SendPort.Send.BinaryTree.14(RunTimeRaw): | 6849.55 us (1 x) | 3705.19 us (1.85 x) | 2507.90 us (2.73 x)
SendPort.Receive.Nop(RunTimeRaw): | 0.67 us (1 x) | 0.69 us (0.97 x) | 0.68 us (0.99 x)
SendPort.Receive.Json.400B(RunTimeRaw): | 4.37 us (1 x) | 0.78 us (5.60 x) | 0.77 us (5.68 x)
SendPort.Receive.Json.5KB(RunTimeRaw): | 45.67 us (1 x) | 0.90 us (50.74 x) | 0.87 us (52.49 x)
SendPort.Receive.Json.50KB(RunTimeRaw): | 498.81 us (1 x) | 1.24 us (402.27 x) | 1.06 us (470.58 x)
SendPort.Receive.Json.500KB(RunTimeRaw): | 5366.02 us (1 x) | 4.22 us (1271.57 x) | 4.65 us (1153.98 x)
SendPort.Receive.Json.5MB(RunTimeRaw): | 101050.88 us (1 x) | 20.81 us (4855.88 x) | 21.0 us (4811.95 x)
SendPort.Receive.BinaryTree.2(RunTimeRaw): | 3.91 us (1 x) | 0.76 us (5.14 x) | 0.74 us (5.28 x)
SendPort.Receive.BinaryTree.4(RunTimeRaw): | 9.90 us (1 x) | 0.79 us (12.53 x) | 0.76 us (13.03 x)
SendPort.Receive.BinaryTree.6(RunTimeRaw): | 33.09 us (1 x) | 0.87 us (38.03 x) | 0.84 us (39.39 x)
SendPort.Receive.BinaryTree.8(RunTimeRaw): | 126.77 us (1 x) | 0.92 us (137.79 x) | 0.88 us (144.06 x)
SendPort.Receive.BinaryTree.10(RunTimeRaw): | 533.09 us (1 x) | 0.94 us (567.12 x) | 0.92 us (579.45 x)
SendPort.Receive.BinaryTree.12(RunTimeRaw): | 2223.23 us (1 x) | 3.03 us (733.74 x) | 3.04 us (731.33 x)
SendPort.Receive.BinaryTree.14(RunTimeRaw): | 8945.66 us (1 x) | 4.03 us (2219.77 x) | 4.30 us (2080.39 x)
```
Issue https://github.com/dart-lang/sdk/issues/36097
TEST=vm/dart{,_2}/isolates/fast_object_copy{,2}_test
Change-Id: I835c59dab573d365b8a4b9d7c5359a6ea8d8b0a7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/203776
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
Lasse R.H. Nielsen